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	2022-12-14: How Can Matter Be BOTH Liquid AND Gas? 00:27: ... fact, there are planets in our solar system completely covered with this stuff, and you’ve often ... 13:42: ... often think of Venus as a rocky planet, but it’s also fair to think of it as an ocean world - an ocean of ... 14:17: But the supercritical layer is an integral part of the structure of the biggest planets in the solar system. 00:27: ... fact, there are planets in our solar system completely covered with this stuff, and you’ve often ... 14:17: But the supercritical layer is an integral part of the structure of the biggest planets in the solar system.
	2022-12-08: How Are Quasiparticles Different From Particles? 15:32: ... ideas – titles like "Other Earths: The Search for Habitable Exoplanets," “Planet Hunting with the James Webb Telescope, or “Killer Asteroid: Defending ...
	2022-11-23: How To See Black Holes By Catching Neutrinos 02:57: In fact, the vast majority pass straight through the entire planet. 06:44: Atmospheric neutrinos are still a problem, because if they’re produced on the other side of the planet they can still reach IceCube. 15:28: But with 8 billion people on the planet, that’s a few every day.
	2022-11-16: Are there Undiscovered Elements Beyond The Periodic Table? 03:36: Those elements eventually find their way into planets, which form from the guts of those stars after they explode as supernovae.
	2022-11-09: What If Humanity Is Among The First Spacefaring Civilizations? 01:30: We are in fact on a typical planet, orbiting a typical star in a typical galaxy. 01:58: ... why it’s not surprising that we’re on a planet at all, rather than floating in a more typical environment: the freezing ... 04:23: In the first couple billion years, the universe didn’t contain enough heavy elements for rocky planets to form. 04:50: Once a habitable star along with its habitable planets have formed, life needs time to evolve. 04:59: We humans only appeared 4 and a bit billion years after our planet formed. 07:04: How long do these habitable planets remain habitable? 07:07: ... the sun will be too hot for liquid water to exist on the surface of the planet. ... 07:23: ... all habitable planets only last this long, then new civilisations would mostly stop appearing ... 07:45: There might be other habitable planets that last a lot longer than the Earth. 07:49: ... live for thousands of times longer than our sun, meaning they could have planets that remain habitable for trillions of ... 08:00: If it’s possible for life to evolve on these planets, then new civilisations could continue to emerge for trillions of years into the future. 08:16: Since they’re very dim, orbiting planets need to be very close to the star in order to have liquid water, which may be necessary for life. 08:23: But planets closer to their star are more likely to be tidally locked. 08:33: The authors of this paper argue that life could well evolve on red dwarf planets. 08:49: So there are two main deciding factors of our birth rank: the number of hard steps and the maximum lifetime of habitable planets. 09:08: Each point represents a choice of hard-step-number and maximum planet lifetime, and the color of that point tells you our birth rank. 09:25: ... only short-lived planets like Earth are habitable and there are few hard steps, then we were born ... 09:47: ... if there are both long-lived habitable planets and many hard steps, then virtually all civilization will result from ... 11:01: The model claims that at some point in the future, all habitable planets will be occupied by rapidly expanding alien civilizations. 11:11: No new life has the chance to evolve, because every planet is already occupied by space-fairing advanced life. 04:59: We humans only appeared 4 and a bit billion years after our planet formed. 09:08: Each point represents a choice of hard-step-number and maximum planet lifetime, and the color of that point tells you our birth rank. 01:30: We are in fact on a typical planet, orbiting a typical star in a typical galaxy. 08:42: But this isn’t the scientific consensus, and notably these researchers are not planetary scientists nor astrobiologists. 04:23: In the first couple billion years, the universe didn’t contain enough heavy elements for rocky planets to form. 04:50: Once a habitable star along with its habitable planets have formed, life needs time to evolve. 07:04: How long do these habitable planets remain habitable? 07:23: ... all habitable planets only last this long, then new civilisations would mostly stop appearing ... 07:45: There might be other habitable planets that last a lot longer than the Earth. 07:49: ... live for thousands of times longer than our sun, meaning they could have planets that remain habitable for trillions of ... 08:00: If it’s possible for life to evolve on these planets, then new civilisations could continue to emerge for trillions of years into the future. 08:16: Since they’re very dim, orbiting planets need to be very close to the star in order to have liquid water, which may be necessary for life. 08:23: But planets closer to their star are more likely to be tidally locked. 08:33: The authors of this paper argue that life could well evolve on red dwarf planets. 08:49: So there are two main deciding factors of our birth rank: the number of hard steps and the maximum lifetime of habitable planets. 09:25: ... only short-lived planets like Earth are habitable and there are few hard steps, then we were born ... 09:47: ... if there are both long-lived habitable planets and many hard steps, then virtually all civilization will result from ... 11:01: The model claims that at some point in the future, all habitable planets will be occupied by rapidly expanding alien civilizations. 08:23: But planets closer to their star are more likely to be tidally locked. 07:04: How long do these habitable planets remain habitable?
	2022-10-26: Why Did Quantum Entanglement Win the Nobel Prize in Physics? 15:49: There was the one about using the Sun’s gravitational field as a lens to take pictures of distant planets. 17:03: Well there’s no real range limit in terms of  what planets will be brought to a focus in the sun’s gravitational focal range. 17:10: In principle you could look at planets in other galaxies. 17:20: ... but not many 1000s of  light years type scales. And  which planets do we do ... 17:37: The report talks about Earth-mass planets around Sun-like stars, of which there are plenty. 15:49: There was the one about using the Sun’s gravitational field as a lens to take pictures of distant planets. 17:03: Well there’s no real range limit in terms of  what planets will be brought to a focus in the sun’s gravitational focal range. 17:10: In principle you could look at planets in other galaxies. 17:20: ... but not many 1000s of  light years type scales. And  which planets do we do ... 17:37: The report talks about Earth-mass planets around Sun-like stars, of which there are plenty.
	2022-10-12: The REAL Possibility of Mapping Alien Planets! 00:33: ... we now know that there are billions of extrasolar   planets - exoplanets - in our galaxy. And we’re learning a ton about them - ... 01:25: ... blurred to the size of the diffraction limit. That’s a problem, because planets are pretty small   when you’re trying to see them from many ... 04:36: ... possible to   even see the thing in the first place. And the planet's surface area would be expanded by a factor of around 100 ... 10:07: ... ring formed from a single tiny patch   on the surface of the planet, only 10km across. In order to see the entire planet it’ll have to ... 12:52: ... colours.   And if we spot bright points of light on the  planet’s night side - aka cities - that would   be pretty compelling ... 01:25: ... surface features. And that’s by sending a spaceship. Not TO the planet - that   would take way too long. In fact, it’s by  sending ... 10:07: ... surface of the planet, only 10km across. In order to see the entire planet it’ll have to move   around the focal column, mapping the surface ... 01:25: ... by bringing together radio signals from telescopes all across the planet,   effectively giving us a planet-sized telescope with a tiny ... 00:33: ... we now know that there are billions of extrasolar   planets - exoplanets - in our galaxy. And we’re learning a ton about them - ... 01:25: ... blurred to the size of the diffraction limit. That’s a problem, because planets are pretty small   when you’re trying to see them from many ... 04:36: ... possible to   even see the thing in the first place. And the planet's surface area would be expanded by a factor of around 100 ... 10:07: ... but also due to the wobble of the Sun as its tugged by the planets of our solar system.   Our telescope is going to execute this ... 12:52: ... colours.   And if we spot bright points of light on the  planet’s night side - aka cities - that would   be pretty compelling ... 00:33: ... we now know that there are billions of extrasolar   planets - exoplanets - in our galaxy. And we’re learning a ton about them - ... 12:52: ... that we build dedicated spacecraft for each of our solar system’s planets - usually more than one of them.   And these little small-sats ... 00:33: ... we now know that there are billions of extrasolar   planets - exoplanets - in our galaxy. And we’re learning a ton about them - for ... 12:52: ... colours.   And if we spot bright points of light on the  planet’s night side - aka cities - that would   be pretty compelling evidence ... 04:36: ... possible to   even see the thing in the first place. And the planet's surface area would be expanded by a factor of around 100 ... 01:25: ... telescopes all across the planet,   effectively giving us a planet-sized telescope with a tiny diffraction limit. We are not yet   ... 00:33: ... mass. Of course if we want to  find life or actually visit these planets   it’d be nice to know a bit more than that. The James Webb Space ...
	2022-09-21: Science of the James Webb Telescope Explained! 00:19: ... now, and has seen some pretty amazing stuff, from colliding galaxies to planets and exoplanet atmospheres to the earliest, most distant galaxies ever ... 04:59: Another key science area is planets. 05:01: IR sensitivity lets us peer into the dusty whirlpools around new stars and watch the formation of planets in action. 05:09: ... also let’s us see the atmospheres of planets in other solar systems, which is an important step towards finding other ... 05:32: ... a coronagraph to block the bright light of a star to better see its planets, to name just a ... 00:19: ... now, and has seen some pretty amazing stuff, from colliding galaxies to planets and exoplanet atmospheres to the earliest, most distant galaxies ever ... 04:59: Another key science area is planets. 05:01: IR sensitivity lets us peer into the dusty whirlpools around new stars and watch the formation of planets in action. 05:09: ... also let’s us see the atmospheres of planets in other solar systems, which is an important step towards finding other ... 05:32: ... a coronagraph to block the bright light of a star to better see its planets, to name just a ...
	2022-08-17: What If Dark Energy is a New Quantum Field? 10:55: ... for why dark energy kicked in at around the same time as stars and planets were able to form. This same “tracker” behavior could also help solve ...
	2022-07-20: What If We Live in a Superdeterministic Universe? 18:30: No Star Trek future unless you can assemble furniture without destroying your planet. 18:07: ... points out, aliens would surely give some tests we could run to not risk planetary destruction.The fact that their designs are cataclysmic if assembled ...
	2022-06-30: Could We Decode Alien Physics? 05:33: ... positrons from electrons,  and hopefully not explode the planet. ... 06:55: ... I dunno,  maybe we create a black hole that eats the   planet. But the definition of handedness  also depends on an arbitrary ... 14:52: ... bake time-reversed antimatter brownies they don't blow up their planet. In fact those things are freaking ... 00:00: ... civilization. Of course  if we get it wrong we might blow up the planet.  How hard can it really be to decode  alien physics and ... 01:25: ... is coming up. But just before  we flip the switch and destroy the planet,   a few cautious scientists take one last look  at the alien ...
	2022-06-22: Is Interstellar Travel Impossible? 00:27: ... a galaxy where billions of planets have had billions of years to spawn technological civilizations, why ... 05:18: These sort of micrometeorites are somewhat common within the solar system - leftovers from the formation of the planetary system. 07:03: Grains larger than this are exceedingly rare outside of planetary system. 13:42: But it turns out there’s nothing in principle stopping us from slowly limping from one planetary system to the next. 05:18: These sort of micrometeorites are somewhat common within the solar system - leftovers from the formation of the planetary system. 07:03: Grains larger than this are exceedingly rare outside of planetary system. 13:42: But it turns out there’s nothing in principle stopping us from slowly limping from one planetary system to the next. 00:27: ... a galaxy where billions of planets have had billions of years to spawn technological civilizations, why ...
	2022-05-25: The Evolution of the Modern Milky Way Galaxy 16:02: ... and such large moons are probably very  rare even if Earth-mass planets are   common. The large moon has been proposed as  an ... 16:41: ... heavy bombardment may have been needed  to seed the surface of the planet with a   high abundance of heavy elements - which was  ... 16:02: ... and such large moons are probably very  rare even if Earth-mass planets are   common. The large moon has been proposed as  an ... 16:41: ... and probably isn’t something experienced by  most terrestrial planets. On the other hand,   some scientists doubt that the late ... 16:02: ... and such large moons are probably very  rare even if Earth-mass planets are   common. The large moon has been proposed as  an important factor in ...
	2022-05-18: What If the Galactic Habitable Zone LIMITS Intelligent Life? 00:24: ... planet has a number of remarkable qualities  that seem to make it ... 03:40: ... Heavier elements clumped together and slowly grew into planets - the smaller ones became terrestrial   planets like the ... 04:32: ... Kepler also revealed that there are around 40  billion Earth-analog planets in the Galaxy,   that means rocky or terrestrial planets in ... 05:52: ... elements. But those elements are critical -  they’re what planets like the Earth are made   out of. So firstly a star needs to ... 07:36: ... which means they couldn’t possibly have formed  planets. No chance for life yet. However these   stars were incredible ... 08:01: ... so for the first time had the chance to build   planets. These stars fell towards the center of  the still-collapsing gas ... 09:08: ... know that having a Jupiter-like  planet or two in the outer solar system   can be useful in protecting ... 10:04: ... stars that they formed - again, not  the most likely places to find planets or ... 00:24: ... significantly less heavy elements it could never have formed a planetary system, but   too much heavy elements and it might host only ... 01:07: ... before. But one possible solution is that the Sun   and its planetary system are really quite unique  in its ability to spawn and nurture ... 04:32: ... there   are several tens of billions of them. Having a  planetary system is also not unusual. The Kepler   mission demonstrated ... 06:56: ... to the formation of the Galaxy   to figure out where habitable planetary systems could have formed in the first place. Our galaxies ... 10:04: ... disk  to seed itself with enough heavy elements to   form planetary systems. In fact, some of  our galaxy still hasn’t had enough ... 11:12: ... we can say a little more about the emergence of  life-friendly planetary systems. And by “we”,   I mean Charlie Lineweaver, Yeshe ... 13:03: ... There is a roadblock in the chain from  forming a habitable planetary system   to sparking simple life to complexifying into ... 00:24: ... significantly less heavy elements it could never have formed a planetary system, but   too much heavy elements and it might host only ... 01:07: ... before. But one possible solution is that the Sun   and its planetary system are really quite unique  in its ability to spawn and nurture ... 04:32: ... there   are several tens of billions of them. Having a  planetary system is also not unusual. The Kepler   mission demonstrated ... 06:56: ... to the formation of the Galaxy   to figure out where habitable planetary systems could have formed in the first place. Our galaxies ... 10:04: ... disk  to seed itself with enough heavy elements to   form planetary systems. In fact, some of  our galaxy still hasn’t had enough ... 11:12: ... we can say a little more about the emergence of  life-friendly planetary systems. And by “we”,   I mean Charlie Lineweaver, Yeshe ... 13:03: ... There is a roadblock in the chain from  forming a habitable planetary system   to sparking simple life to complexifying into ... 10:04: ... disk  to seed itself with enough heavy elements to   form planetary systems. In fact, some of  our galaxy still hasn’t had enough ... 11:12: ... we can say a little more about the emergence of  life-friendly planetary systems. And by “we”,   I mean Charlie Lineweaver, Yeshe Fenner and ... 06:56: ... to the formation of the Galaxy   to figure out where habitable planetary systems could have formed in the first place. Our galaxies started   like ... 11:12: ... estimated the  historical emergence of life-friendly planetary   systems accounting for all the stuff we talked  about. They started ... 13:03: ... about the others.   There is something special about this planetary system, even with our personal bias that we orbit   most important and ... 03:40: ... Heavier elements clumped together and slowly grew into planets - the smaller ones became terrestrial   planets like the ... 04:32: ... Kepler also revealed that there are around 40  billion Earth-analog planets in the Galaxy,   that means rocky or terrestrial planets in ... 05:52: ... elements. But those elements are critical -  they’re what planets like the Earth are made   out of. So firstly a star needs to ... 07:36: ... which means they couldn’t possibly have formed  planets. No chance for life yet. However these   stars were incredible ... 08:01: ... so for the first time had the chance to build   planets. These stars fell towards the center of  the still-collapsing gas ... 09:08: ... but gas giants can also disrupt or destroy  terrestrial planets. A system with multiple   Jupiter-like planets probably ... 10:04: ... stars that they formed - again, not  the most likely places to find planets or ... 03:40: ... Heavier elements clumped together and slowly grew into planets - the smaller ones became terrestrial   planets like the Earth, ... 04:32: ... The Kepler   mission demonstrated that most stars have planets  - at least in the local part of the galaxy.   Kepler also ... 08:01: ... highest in the galaxy,   and high metallicity means too many planets  - in particular, too many giant ... 04:32: ... The Kepler   mission demonstrated that most stars have planets  - at least in the local part of the galaxy.   Kepler also ... 08:01: ... highest in the galaxy,   and high metallicity means too many planets  - in particular, too many giant ... 04:32: ... of light is in the  right range to allow liquid water on the planet’s   surface. So it sounds like the galaxy should  be full of potential ... 11:12: ... and folded in estimates for  the probability of the emergence of planets   based on heavy element abundance; the likelihood  of surviving ... 04:32: ... of light is in the  right range to allow liquid water on the planet’s   surface. So it sounds like the galaxy should  be full of potential starting ...
	2022-05-04: Space DOES NOT Expand Everywhere 01:24: ... in space tend to move around due to nearby gravitational influences - planets orbit stars, stars orbit in the mutual gravity of their galaxies, ...
	2022-03-30: Could The Universe Be Inside A Black Hole? 04:13: ... be the path that the ball would follow if it could pass through the planet, or the path through the ground that could have brought the ball to its ...
	2022-03-23: Where Is The Center of The Universe? 00:25: ... Nicolaus Copernicus shoved us from our pedestal onto a random rocky planet orbiting an ordinary star in the outskirts of an unremarkable ... 14:59: ... asks whether the massive tides that the Proxima planets experience might be ideal for life due to the rich biodiversity of ... 15:41: Tidal squeezing should indeed help keep the planet’s interior hot, just like it does on the volcanic moons of Jupiter and Saturn. 15:48: For a planet that would presumable help drive tectonic activity. 16:22: So in short those tidal forces on those Proxima planets may make it more likely that there's life. 00:25: ... Nicolaus Copernicus shoved us from our pedestal onto a random rocky planet orbiting an ordinary star in the outskirts of an unremarkable ... 14:59: ... asks whether the massive tides that the Proxima planets experience might be ideal for life due to the rich biodiversity of ... 15:41: Tidal squeezing should indeed help keep the planet’s interior hot, just like it does on the volcanic moons of Jupiter and Saturn. 16:22: So in short those tidal forces on those Proxima planets may make it more likely that there's life. 14:59: ... asks whether the massive tides that the Proxima planets experience might be ideal for life due to the rich biodiversity of Earth’s ... 15:41: Tidal squeezing should indeed help keep the planet’s interior hot, just like it does on the volcanic moons of Jupiter and Saturn.
	2022-03-08: Is the Proxima System Our Best Hope For Another Earth? 01:55: Perhaps they also bore planetary systems - and even planets like the Earth. 03:50: In 2016, Spanish astronomer Guillem Anglada-Escudé  and the Pale Red Dot team figured it out: Proxima had a planet. 04:01: Or more technically an exoplanet - for extra-solar planet. 04:05: Planets don’t really orbit stars. 04:15: Planets make stars wobble, and that motion induces something called Doppler shift in the star’s emission lines. 05:07: ... exoplanets has been the transit method,   in which planets are identified by their dimming of their parent star as they cross or ... 08:36: ... there are admittedly much  more tentative detections   of planets around its Sun-like siblings - a Neptunish body may have been imaged ... 09:17: ... to the star means strong tidal forces, which will have forced the planet’s rotation period to be in resonance with its orbital ... 09:27: The simplest case is for the length of the planet’s day to be the same as its year - both 11.2 earth days. 09:34: That would keep the same side of the planet facing the star at all times. 10:14: Or if the planet has significant oceans, these could also distribute heat. 10:20: It’s also possible for a planet to be tidally locked without a perpetual day and night. 10:52: In that case, the dark side might be the only survivable part of the planet, as long as there’s enough atmospheric cycling to keep it warm. 13:19: ... B’s atmosphere, if it has one, or even the light reflected from the planet’s ... 15:04: ... will wonder if the stories are true - that people began there, on a planet around Sol, Alpha-Centauri’s nearest neighbor across ... 09:34: That would keep the same side of the planet facing the star at all times. 01:55: Perhaps they also bore planetary systems - and even planets like the Earth. 04:53: We couldn’t see a planetary system that’s “face-on” - fully in the plane of the sky. 05:20: That restricts the transit method to planetary systems that are almost perfectly edge-on. 05:26: Nonetheless the Kepler mission found 2600+ exoplanets this way, and extrapolating from that revealed that most stars host planetary systems. 08:30: We have a bona fide planetary system in at least one of the stars in the Alpha-Cen system. 11:22: ... - flares - that blast high energy particles and radiation through the planetary ... 11:43: ... sufficiently thick atmosphere and strong planetary magnetic field could in principle protect any surface dwellers, who ... 12:50: ... not crazy, because planetary formation models indicate that there wouldn’t have been enough material ... 01:55: Perhaps they also bore planetary systems - and even planets like the Earth. 04:53: We couldn’t see a planetary system that’s “face-on” - fully in the plane of the sky. 05:20: That restricts the transit method to planetary systems that are almost perfectly edge-on. 05:26: Nonetheless the Kepler mission found 2600+ exoplanets this way, and extrapolating from that revealed that most stars host planetary systems. 08:30: We have a bona fide planetary system in at least one of the stars in the Alpha-Cen system. 11:22: ... - flares - that blast high energy particles and radiation through the planetary ... 11:43: ... sufficiently thick atmosphere and strong planetary magnetic field could in principle protect any surface dwellers, who ... 12:50: ... not crazy, because planetary formation models indicate that there wouldn’t have been enough material ... 11:43: ... sufficiently thick atmosphere and strong planetary magnetic field could in principle protect any surface dwellers, who would then ... 01:55: Perhaps they also bore planetary systems - and even planets like the Earth. 05:20: That restricts the transit method to planetary systems that are almost perfectly edge-on. 05:26: Nonetheless the Kepler mission found 2600+ exoplanets this way, and extrapolating from that revealed that most stars host planetary systems. 01:55: Perhaps they also bore planetary systems - and even planets like the Earth. 04:05: Planets don’t really orbit stars. 04:15: Planets make stars wobble, and that motion induces something called Doppler shift in the star’s emission lines. 05:07: ... exoplanets has been the transit method,   in which planets are identified by their dimming of their parent star as they cross or ... 08:36: ... there are admittedly much  more tentative detections   of planets around its Sun-like siblings - a Neptunish body may have been imaged ... 09:17: ... to the star means strong tidal forces, which will have forced the planet’s rotation period to be in resonance with its orbital ... 09:27: The simplest case is for the length of the planet’s day to be the same as its year - both 11.2 earth days. 13:19: ... B’s atmosphere, if it has one, or even the light reflected from the planet’s ... 09:27: The simplest case is for the length of the planet’s day to be the same as its year - both 11.2 earth days. 04:05: Planets don’t really orbit stars. 09:17: ... to the star means strong tidal forces, which will have forced the planet’s rotation period to be in resonance with its orbital ... 13:19: ... B’s atmosphere, if it has one, or even the light reflected from the planet’s surface. ... 04:08: A planet-star pair mutually orbits its shared center of mass - its barycenter - which is usually deep inside the star. 10:01: ... differential drives powerful  atmospheric convection - planet-wide gales of extraordinary strength that could distribute heat from the ... 14:37: A descendent of humanity stands on the black grassy plains of Proxima B, which sway in the planet-wide gale. 10:01: ... differential drives powerful  atmospheric convection - planet-wide gales of extraordinary strength that could distribute heat from the ... 14:37: A descendent of humanity stands on the black grassy plains of Proxima B, which sway in the planet-wide gale. 10:01: ... differential drives powerful  atmospheric convection - planet-wide gales of extraordinary strength that could distribute heat from the day-side ...
	2022-02-23: Are Cosmic Strings Cracks in the Universe? 07:33: ... amount of energy, which gives it the mass of the planet Mars for every 100 meters of ...
	2022-01-27: How Does Gravity Escape A Black Hole? 13:06: ... exploring how we do simulations of everything from the sizes of planets to the size of the ...
	2022-01-19: How To Build The Universe in a Computer 01:04: We routinely simulate the universe on all of its scales, from planets to large fractions of the cosmos. 08:08: All of these processes are key parts of galaxy evolution and of star and planet formation, and so we’d better be able to simulate this too. 08:45: ... flows of gas in galaxies and around quasars, used to simulate star and planet formation,   and even star and planet destruction  in ... 09:53: We can see how stars form in multitudes from  collapsing gas clouds, and how planets then coalesce in the disks surrounding those stars. 08:45: ... to simulate star and planet formation,   and even star and planet destruction  in collisions or ... 08:08: All of these processes are key parts of galaxy evolution and of star and planet formation, and so we’d better be able to simulate this too. 08:45: ... flows of gas in galaxies and around quasars, used to simulate star and planet formation,   and even star and planet destruction  in collisions or ... 01:04: We routinely simulate the universe on all of its scales, from planets to large fractions of the cosmos. 09:53: We can see how stars form in multitudes from  collapsing gas clouds, and how planets then coalesce in the disks surrounding those stars.
	2022-01-12: How To Simulate The Universe With DFT 00:10: Would it be: a solar system, a planet, a cat? 16:08: But it would need to reach Earth’s surface moving at 10 or so km/s to get stuck in the planet - perhaps after a couple of passes. 19:24: As in the rest masses of entire planets. 16:08: But it would need to reach Earth’s surface moving at 10 or so km/s to get stuck in the planet - perhaps after a couple of passes. 19:24: As in the rest masses of entire planets. 19:55: Basically, this is a planet-sized computer that could run a virtual world supporting our uploaded minds as virtual intelligences.
	2021-12-29: How to Find ALIEN Dyson Spheres 01:00: ... Sun’s light - a billion times more than what we’d get just covering the planet in solar ... 01:38: ... occupy an entire sphere surrounding its home star at the radius of its planet of origin, for the purpose of both habitation and energy ... 04:21: Anything capable of producing that much power at that low a temperature must be huge - the size of a planetary orbit. 05:06: ... disk of gas surrounding a new-born star that will eventually form planetary ... 04:21: Anything capable of producing that much power at that low a temperature must be huge - the size of a planetary orbit. 05:06: ... disk of gas surrounding a new-born star that will eventually form planetary ... 04:21: Anything capable of producing that much power at that low a temperature must be huge - the size of a planetary orbit. 05:06: ... disk of gas surrounding a new-born star that will eventually form planetary systems. ... 04:58: Unfortunately, there are some obvious natural explanations for a planetary-orbit-sized object at a few hundred Kelvin temperature. 02:38: Earth’s biosphere is already a pretty good planet-scale solar collector.
	2021-12-20: What Happens If A Black Hole Hits Earth? 00:29: ... allow for black holes to pass through our solar system - and even the planet - with startling frequency. In fact it may have already ... 05:06: It would punch straight through the planet like a bullet through cotton candy, barely slowing down in the process. 05:13: ... which is tiny for the Earth, and it’s even tiny for that black hole. The planet barely notices the passage. But I do not recommend standing right under ... 07:29: ... shockwave before hitting the ground and tunneling through the planet. ... 08:16: ... the Earth’s atmosphere, and a black hole’s exit on the other side of the planet should have made another. These days standard narrative is that the ... 00:29: ... allow for black holes to pass through our solar system - and even the planet - with startling frequency. In fact it may have already ... 05:13: ... which is tiny for the Earth, and it’s even tiny for that black hole. The planet barely notices the passage. But I do not recommend standing right under a ...
	2021-11-17: Are Black Holes Actually Fuzzballs? 15:05: ... PhD examined Martian Atmospheric Haze and he worked with the most famous planetary scientist of all - Carl ...
	2021-11-02: Is ACTION The Most Fundamental Property in Physics? 05:52: ... of the Action that we can minimize to find Mercury’s orbit. After all, planets trade between potential and kinetic energy as they move around their ...
	2021-09-07: First Detection of Light from Behind a Black Hole 01:38: ... to achieve an image resolution equivalent to a telescope the size of the planet ... 01:59: ... method doesn’t need an international team or a planet-sized telescope - it can be done with a single, ordinary scope, and one ...
	2021-08-18: How Vacuum Decay Would Destroy The Universe 00:21: ... just the right particle properties to allow stars and   planets and people to exist. The habitability of our universe is largely ...
	2021-08-03: How An Extreme New Star Could Change All Cosmology 06:17: That’s true of planets and regular stars, but it’s not true of white dwarfs. 07:24: ... about what happens when you add mass to less weird space-stuff, say a planet or a star. The matter inside is crushed closer together until there’s ... 09:51: ... also explains the intense magnetic fields. Magnetic fields in stars and planets are generated by dynamos - self-sustaining currents of charged ... 15:05: ... universe, exploring how magnetism shapes our cosmos from the scale of planets up to entire galaxies. That magnetic episode .. attracted many ... 15:55: ... field is very weak compared to the magnetic fields of stars, or even planets. Stars don’t respond to that field directly. However gas does respond to ... 06:17: That’s true of planets and regular stars, but it’s not true of white dwarfs. 09:51: ... also explains the intense magnetic fields. Magnetic fields in stars and planets are generated by dynamos - self-sustaining currents of charged ... 15:05: ... universe, exploring how magnetism shapes our cosmos from the scale of planets up to entire galaxies. That magnetic episode .. attracted many ... 15:55: ... field is very weak compared to the magnetic fields of stars, or even planets. Stars don’t respond to that field directly. However gas does respond to ...
	2021-07-21: How Magnetism Shapes The Universe 04:49: This is still the Sun’s magnetic field, which connects here and there to the piddling little fields of the planets.
	2021-05-11: How To Know If It's Aliens 00:24: ... dropped landing craft, which descended to opposite sides of the planet. This was the Viking mission - the first successful Martian landing by ... 11:24: ... recently shown to have a planetary system, including a nearly Earth-mass planet it its habitable zone, where liquid water is possible. Now the ... 15:39: ... trip would become a beam of energy powerful enough to destroy a planet. ... 11:24: ... exciting because Proxima Cen was also recently shown to have a planetary system, including a nearly Earth-mass planet it its habitable zone, ...
	2021-04-13: What If Dark Matter Is Just Black Holes? 00:00: ... of microscopic black holes streaming through the solar system, the planet, even our bodies every ... 07:36: Ok, let’s move up the black hole mass spectrum to masses around that of a planet.
	2021-03-16: The NEW Crisis in Cosmology 17:08: ... fields - star destroyers,   the death star, forest moons, ice planets - must be hard to recalibrate every time. Who knew ...
	2021-02-24: Does Time Cause Gravity? 02:27: OK, now let’s add a second object - something nice and massive … the planet Earth will do.
	2021-02-17: Gravitational Wave Background Discovered? 00:00: ... timing array which combines many of the largest radio telescopes on the planet to monitor around 100 millisecond pulsars nanograv's own pulsar timing ...
	2021-02-10: How Does Gravity Warp the Flow of Time? 00:11: But that tiny difference in flow of time may be what keeps you stuck to this planet at all.
	2021-01-26: Is Dark Matter Made of Particles? 15:25: ... to the traveling twin, as though they were standing on the surface of a planet with the same gravitational ...
	2021-01-12: What Happens During a Quantum Jump? 03:40: ... jumps to that of epicycles—the long dead theory about the motion of the planets in an Earth-centered solar ...
	2020-12-22: Navigating with Quantum Entanglement 03:41: The result is a dipole field, similar to that of a bar magnet: two poles connected by force lines forming a sort of cage around the planet.
	2020-12-15: The Supernova At The End of Time 02:54: On one of those planets - the third one out - a steamship is making its slow journey to a place that the local carbon based lifeforms call “England”. 02:39: ... its extremely brief phase as a bright ball of hydrogen, bathing a young planetary system in the energy produced by its fusion ... 02:54: On one of those planets - the third one out - a steamship is making its slow journey to a place that the local carbon based lifeforms call “England”.
	2020-10-13: Do the Past and Future Exist? 14:03: ... - would it have been easier to kickstart life from scratch on two planets independently, or have a spacefaring bugs propogate after ... 14:36: ... explained in terms of a great filter - something reliably stops planets from spawning space-faring ... 14:03: ... - would it have been easier to kickstart life from scratch on two planets independently, or have a spacefaring bugs propogate after ... 14:36: ... explained in terms of a great filter - something reliably stops planets from spawning space-faring ... 14:03: ... - would it have been easier to kickstart life from scratch on two planets independently, or have a spacefaring bugs propogate after ...
	2020-10-05: Venus May Have Life! 01:55: To the outer solar system - Mars, Enceladus and Europa in particular, and ultimately to planets around other stars. 03:31: ... life is to detect so-called atmospheric biosignatures - chemicals in a planet’s atmosphere that are very hard to explain without the presence of ... 03:44: There are lots of ways to do this - for example seeing the effect on a star’s light as it passes through its own planets atmospheres. 03:51: Another possibility is to look for the absorption of the planet’s own light as it emerges from deep within its atmosphere. 04:31: ... Maxwell telescope - more as a control to help guide their studies of planets beyond our solar system, but not really expecting to see anything so ... 12:58: ... with deep science storytelling to reveal all the things shaping our planet from the 10,000 foot ... 01:05: It’s bright because it’s close and it’s big, at 90% Earth’s diameter, and its our closest planetary neighbor. 12:15: The discovery of alien life in our nearest planetary neighbor would totally change our calculations about the frequency of life in the universe. 01:05: It’s bright because it’s close and it’s big, at 90% Earth’s diameter, and its our closest planetary neighbor. 12:15: The discovery of alien life in our nearest planetary neighbor would totally change our calculations about the frequency of life in the universe. 01:05: It’s bright because it’s close and it’s big, at 90% Earth’s diameter, and its our closest planetary neighbor. 12:15: The discovery of alien life in our nearest planetary neighbor would totally change our calculations about the frequency of life in the universe. 01:55: To the outer solar system - Mars, Enceladus and Europa in particular, and ultimately to planets around other stars. 03:31: ... life is to detect so-called atmospheric biosignatures - chemicals in a planet’s atmosphere that are very hard to explain without the presence of ... 03:44: There are lots of ways to do this - for example seeing the effect on a star’s light as it passes through its own planets atmospheres. 03:51: Another possibility is to look for the absorption of the planet’s own light as it emerges from deep within its atmosphere. 04:31: ... Maxwell telescope - more as a control to help guide their studies of planets beyond our solar system, but not really expecting to see anything so ... 03:31: ... life is to detect so-called atmospheric biosignatures - chemicals in a planet’s atmosphere that are very hard to explain without the presence of ... 03:44: There are lots of ways to do this - for example seeing the effect on a star’s light as it passes through its own planets atmospheres.
	2020-09-08: The Truth About Beauty in Physics 01:07: A prime example is our effort to understand the motion of the planets. 01:12: ... the first effort, by Claudius Ptolemy, the planets orbited the Earth in complicated systems of circles embedded within ... 01:26: Nicholaus Copernicus found more beauty of simplicity by placing the Earth along with all planets in simple circular orbits around the Sun. 01:58: But the planets move in ellipses, not circles - as deduced a century after Copernicus by Johanne Kepler. 02:27: Not only can Kepler’s complicated laws be derived from Newton, but Newtonian gravity makes predictions far beyond the motion of the planets. 05:32: ... circles within circles could describe the motion of anything, from a planet to a particle of air - but it wouldn’t explain that ... 02:04: Kepler’s three laws of planetary motion are arguably much less elegant than Copernicus’ simple model - a touch uglier. 02:19: There IS an extremely simple, elegant law underlying planetary motion - it's Newton’s Law of Universal Gravitation. 02:04: Kepler’s three laws of planetary motion are arguably much less elegant than Copernicus’ simple model - a touch uglier. 02:19: There IS an extremely simple, elegant law underlying planetary motion - it's Newton’s Law of Universal Gravitation. 02:04: Kepler’s three laws of planetary motion are arguably much less elegant than Copernicus’ simple model - a touch uglier. 02:19: There IS an extremely simple, elegant law underlying planetary motion - it's Newton’s Law of Universal Gravitation. 01:07: A prime example is our effort to understand the motion of the planets. 01:12: ... the first effort, by Claudius Ptolemy, the planets orbited the Earth in complicated systems of circles embedded within ... 01:26: Nicholaus Copernicus found more beauty of simplicity by placing the Earth along with all planets in simple circular orbits around the Sun. 01:58: But the planets move in ellipses, not circles - as deduced a century after Copernicus by Johanne Kepler. 02:27: Not only can Kepler’s complicated laws be derived from Newton, but Newtonian gravity makes predictions far beyond the motion of the planets. 01:12: ... the first effort, by Claudius Ptolemy, the planets orbited the Earth in complicated systems of circles embedded within circles - ...
	2020-08-17: How Stars Destroy Each Other 00:44: Ejecting its outer layers, it became a searing hot, planet-sized orb of incredible density - a white dwarf. 01:22: ... storm of fusion ripped around the planet-sized white dwarf, spraying its atmosphere into space and for a couple of ... 00:44: Ejecting its outer layers, it became a searing hot, planet-sized orb of incredible density - a white dwarf. 01:22: ... storm of fusion ripped around the planet-sized white dwarf, spraying its atmosphere into space and for a couple of ... 00:44: Ejecting its outer layers, it became a searing hot, planet-sized orb of incredible density - a white dwarf. 01:22: ... storm of fusion ripped around the planet-sized white dwarf, spraying its atmosphere into space and for a couple of weeks ...
	2020-08-10: Theory of Everything Controversies: Livestream 00:00: ... big collider or you have to build a graviton detector the size of the planet jupiter and put it in orbit around the neutron stars stuff like this ...
	2020-07-28: What is a Theory of Everything: Livestream 00:00: ... a sixth platonic solid it just doesn't exist right the way another planet in our solar system doesn't so that's that the in terms of what you ...
	2020-06-22: Building Black Holes in a Lab 00:16: ... away and on cosmic scales very tiny. It took a telescope the size of the planet to be able to make an image of the nearest gigantic one. Nonetheless, ...
	2020-06-15: What Happens After the Universe Ends? 15:16: In our recent episode we looked at the possibility that viruses can travel between planets.
	2020-06-08: Can Viruses Travel Between Planets? 00:50: That’s right, viruses or their ancestors may have played a role in the origin of life on earth, and may be needed to initiate life on any planet. 04:43: ... frequencies plucked from the starlight due to it passing through that planet’s ... 05:45: ... red planet seems pretty dead these days, but it’s conceivable that an ecosystem of ... 06:49: Can viruses from one planet infect another? 07:26: ... can be lifted to the very edge of an atmosphere with the help of the planet’s magnetic field and then swept into interplanetary or even interstellar ... 06:49: Can viruses from one planet infect another? 00:17: And that’s because it turns out viruses don’t just influence organisms - they’re incredibly important on a planetary scales. 01:37: I want to do this review to highlight the details of viruses that make them important on a planetary, and even interplanetary scales. 10:37: ... that’s the only known way to really spread LOTS of viruses between planetary ... 00:17: And that’s because it turns out viruses don’t just influence organisms - they’re incredibly important on a planetary scales. 01:37: I want to do this review to highlight the details of viruses that make them important on a planetary, and even interplanetary scales. 10:37: ... that’s the only known way to really spread LOTS of viruses between planetary ... 00:17: And that’s because it turns out viruses don’t just influence organisms - they’re incredibly important on a planetary scales. 10:37: ... that’s the only known way to really spread LOTS of viruses between planetary systems. ... 04:43: ... frequencies plucked from the starlight due to it passing through that planet’s ... 07:26: ... can be lifted to the very edge of an atmosphere with the help of the planet’s magnetic field and then swept into interplanetary or even interstellar ... 04:43: ... frequencies plucked from the starlight due to it passing through that planet’s atmosphere. ... 07:26: ... can be lifted to the very edge of an atmosphere with the help of the planet’s magnetic field and then swept into interplanetary or even interstellar space by ...
	2020-05-11: How Luminiferous Aether Led to Relativity 04:06: ... was bunk. He reasoned that if any medium filled the space between the planets, surely it would cause a sort of drag that would impede their apparently ... 08:02: ... But why build a fast-moving lab when you already have a fast-moving planet? Earth hurtles around the Sun at 30 km/s - that’s only one one hundredth ... 04:06: ... was bunk. He reasoned that if any medium filled the space between the planets, surely it would cause a sort of drag that would impede their apparently ...
	2020-04-22: Will Wormholes Allow Fast Interstellar Travel? 16:25: Along with the entire planet. Way to make me feel better about being locked in my apartment, which I now see as a cool spaceship.
	2020-04-07: How We Know The Earth Is Ancient 03:30: ... the Earth for opening scientific eyes to the possibility of an ancient planet, and the idea of what we now call deep ... 04:32: ... space. We’d known since Copernicus and Galileo that earth was just one planet among several in our solar system. Astronomers now swear by the ... 05:50: ... for that formation, but we now know much lower than the true age of the planet. ... 11:02: ... formed at the same time as the Earth - both coallescing after a giant planetary impact in the early solar system. Now the moon is tectonically inactive, ...
	2020-03-31: What’s On The Other Side Of A Black Hole? 00:37: ... the Earth in lines of longitude and latitude so that every point on the planet can be clearly defined with two numbers. Everywhere but at the north and ...
	2020-01-20: Solving the Three Body Problem 03:18: ... most of the three centuries since Newton, predicting the motion of the planets and the moon was critical for nautical navigation. Now it’s essential to ... 04:12: ... example, each planet of our solar system can be thought of as a separate two-body system with ... 04:24: But those orbits eventually shift due to the interactions between the planets. 06:20: ... computers, N-body simulations can accurately predict the motion of the planets into the distant future or solve for millions of objects to simulate the ... 00:20: ... the beauty of Newton’s equations, they lead to a simple solution for planetary motion in only one case - when two and only two bodies orbit each other ... 02:06: ... bodies - be it the parabola of a thrown ball, the circle or ellipse of a planetary orbit, or the hyperbola of an interstellar comet - in general, conic ... 05:01: ... are useful, but ultimately fail to predict perfectly. Even the smallest planetary bodies have some mass, and the solar system as a whole has many massive ... 00:20: ... the beauty of Newton’s equations, they lead to a simple solution for planetary motion in only one case - when two and only two bodies orbit each other ... 02:06: ... bodies - be it the parabola of a thrown ball, the circle or ellipse of a planetary orbit, or the hyperbola of an interstellar comet - in general, conic ... 05:01: ... are useful, but ultimately fail to predict perfectly. Even the smallest planetary bodies have some mass, and the solar system as a whole has many massive ... 00:20: ... the beauty of Newton’s equations, they lead to a simple solution for planetary motion in only one case - when two and only two bodies orbit each other sans ... 02:06: ... that Johanne Kepler figured out much about the elliptical solution for planetary motion 70 years before Newton’s laws were even ... 03:18: ... most of the three centuries since Newton, predicting the motion of the planets and the moon was critical for nautical navigation. Now it’s essential to ... 04:24: But those orbits eventually shift due to the interactions between the planets. 06:20: ... computers, N-body simulations can accurately predict the motion of the planets into the distant future or solve for millions of objects to simulate the ...
	2020-01-13: How To Capture Black Holes 06:15: ... each other. This is really cool, because the process is similar to how planets form. When a massive object is embedded in a rotating disk, it will ... 07:17: ... migrate to these traps, where they can find each other and build into planets. In the case of accretion disks, the “planets” are black holes - captured ... 06:15: ... each other. This is really cool, because the process is similar to how planets form. When a massive object is embedded in a rotating disk, it will ... 07:17: ... migrate to these traps, where they can find each other and build into planets. In the case of accretion disks, the “planets” are black holes - captured ... 06:15: ... each other. This is really cool, because the process is similar to how planets form. When a massive object is embedded in a rotating disk, it will exert a ...
	2019-12-17: Do Black Holes Create New Universes? 09:09: ... massive stars die, they actually mostly produce neutron stars - planet sized balls of neutrons so dense that they teeter on the edge of ... 02:52: The universe that is better at making stars is better at making planetary systems is better at making us.
	2019-12-09: The Doomsday Argument 00:25: ... principle and seen how it can be used to explain the fact that both our planet and our universe seem very finely tuned to allow the development of ... 00:37: ... planet and/or universe can be rare and unlikely as long as there are enough ... 10:42: ... common ways that your current self exists besides evolving on a rare planet in a rare ... 00:37: ... planet and/or universe can be rare and unlikely as long as there are enough other ...
	2019-11-18: Can You Observe a Typical Universe? 00:34: ... from its position at the center of the universe into just one of several planets orbiting the ... 01:55: ... planet and our universe must have at least one non-typical quality - they must ... 02:13: ... we talked about certain observations of the uniqueness both of our planet and of the universe, and how these feed into two versions of the ... 03:01: That means the fundamental constants and initial conditions of the universe must be just right to allow nice habitable planets to form. 03:10: ... an environment capable of producing observers; be that environment a planet within a universe or a universe within a ... 08:48: ... surely don’t need more than one galaxy to spawn a life-bearing planet - so there should be many more observers in small entropy fluctuations ... 11:49: It’s one possible explanation for why our planet and our universe appear to fit us so well, even if they weren’t intentionally made for us. 08:48: ... surely don’t need more than one galaxy to spawn a life-bearing planet - so there should be many more observers in small entropy fluctuations ... 16:26: ... if this were the Goldilocks universe there would be life on almost every planetary body, even in this solar ... 00:34: ... from its position at the center of the universe into just one of several planets orbiting the ... 03:01: That means the fundamental constants and initial conditions of the universe must be just right to allow nice habitable planets to form. 00:34: ... from its position at the center of the universe into just one of several planets orbiting the ...
	2019-11-11: Does Life Need a Multiverse to Exist? 03:13: ... neither version of the anthropic principle explain why life-friendly planets or universes exist; they just say that if such places do exist at all, ... 03:36: ... tuned universes exist as well - in the same way that many uninhabitable planets ... 05:28: Carbon would no longer be abundant on the surfaces of new planets, making the emergence carbon-based life near impossible. 10:55: ... with the right physics for life - just like we’re on one of the few planets with the conditions suitable for ... 13:09: ... the last episode we discussed the Rare Earth Hypothesis - the idea that planets supporting intelligent life may be extremely rare, and how this relates ... 13:40: ... scenario is that some mars-sized planet plowed into early earth, causing a lot of Earth's rocky crust to be ... 13:50: Meanwhile, Earth's iron core would have grown as it absorved the iron core of the smaller planet. 14:04: ... inner solar system during the solar system's formation, disrupting the planets that were forming there before moving back out again to its current ... 14:15: Now, the current inner planets are therefore much smaller than they would have been because they had to form from the leftover material. 14:24: If life requires smaller rocky planets rather than super-earths then this could definitely be a rare-earth property. 14:52: ... do seem to be quite a lot of qualities that are very non-standard for planets, even as we learn more and more about other planetary ... 15:24: ... tuning of the universe is hard to deny - the fine tuning of our planet is less clear, but the weak anthropic principle makes it a totally ... 13:40: ... scenario is that some mars-sized planet plowed into early earth, causing a lot of Earth's rocky crust to be thrown into ... 14:52: ... non-standard for planets, even as we learn more and more about other planetary ... 03:13: ... neither version of the anthropic principle explain why life-friendly planets or universes exist; they just say that if such places do exist at all, ... 03:36: ... tuned universes exist as well - in the same way that many uninhabitable planets ... 05:28: Carbon would no longer be abundant on the surfaces of new planets, making the emergence carbon-based life near impossible. 10:55: ... with the right physics for life - just like we’re on one of the few planets with the conditions suitable for ... 13:09: ... the last episode we discussed the Rare Earth Hypothesis - the idea that planets supporting intelligent life may be extremely rare, and how this relates ... 14:04: ... inner solar system during the solar system's formation, disrupting the planets that were forming there before moving back out again to its current ... 14:15: Now, the current inner planets are therefore much smaller than they would have been because they had to form from the leftover material. 14:24: If life requires smaller rocky planets rather than super-earths then this could definitely be a rare-earth property. 14:52: ... do seem to be quite a lot of qualities that are very non-standard for planets, even as we learn more and more about other planetary ... 03:36: ... tuned universes exist as well - in the same way that many uninhabitable planets exist. ... 05:28: Carbon would no longer be abundant on the surfaces of new planets, making the emergence carbon-based life near impossible. 13:09: ... the last episode we discussed the Rare Earth Hypothesis - the idea that planets supporting intelligent life may be extremely rare, and how this relates to the weak ...
	2019-11-04: Why We Might Be Alone in the Universe 00:30: It shouldn’t be surprising that we live on a planet that can support our existence, in a universe that can produce such planets. 02:33: For example, if there’s only one life-bearing planet in the galaxy, or in the universe, you’re going to be on it. 02:51: This hypothesis was inspired by some striking observations about our home planet, which I’ll get to - but also by one other piece of evidence. 03:22: ... exceedingly rare - and maybe that’s because Earth is an exceedingly rare planet. ... 03:35: ... - extremely difficult or unlikely steps in the development from barren planet to visible technological ... 03:58: ... the Rare Earth hypothesis is a little more optimistic - it states that planets capable of spawning civilizations even at our own level are very ... 04:14: It highlights a series of remarkable qualities of planet Earth that may have been needed for life and intelligence to arise here. 04:29: Earth-like planets are common. 04:31: ... by Earth-like I mean rocky planets about the size of the Earth in orbit around stars very similar to the ... 04:53: ... even if we restrict ourselves to boring old carbon-based water-loving planet ... 05:02: ... billions of planets stewing for billions of years - if only one civilization had a tiny head ... 05:12: Unless Earth has special qualities that mean true Earth-like planets are much rarer. 05:21: If we see that even one other planet has some life-critical quality, then we know that that quality could be relatively common. 05:28: ... still not surprising for us to find ourselves on one of the very few planets with that ... 05:41: We’ll start by comparing planets of our solar system, because our ability to probe extra-solar planets is still in its infancy. 05:48: ... Earth has two qualities not shared by the other rocky planets in our solar system: 1) it has a very dynamic interior and 2) a very ... 07:12: Earth’s moon is ridiculously gigantic - no other rocky planet in our system has anything like it. 07:19: Its size and also its composition and orbit suggest that it formed when a Mars-ish sized planet collided with the Earth right after its formation. 09:14: Our solar system has a huge range of planet properties - from the tiny rocky Mercury to the gigantic gaseous Jupiter and Saturn. 09:23: ... contrast, the planets of most other systems tend to be all around the same size as each other ... 09:40: That planet acts like a gigantic gravitational vacuum cleaner, absorbing a lot of the debris left over from the formation of the solar system. 11:54: It’s very possible that a combination of extremely unlikely factors means it’s extremely rare for planets to spawn intelligence. 09:40: That planet acts like a gigantic gravitational vacuum cleaner, absorbing a lot of the debris left over from the formation of the solar system. 07:19: Its size and also its composition and orbit suggest that it formed when a Mars-ish sized planet collided with the Earth right after its formation. 04:14: It highlights a series of remarkable qualities of planet Earth that may have been needed for life and intelligence to arise here. 04:53: ... even if we restrict ourselves to boring old carbon-based water-loving planet life. ... 09:14: Our solar system has a huge range of planet properties - from the tiny rocky Mercury to the gigantic gaseous Jupiter and Saturn. 01:22: For example, in a planetary biosphere rather than floating in the void between the galaxies. 09:06: Our entire planetary system is pretty weird. 09:09: We’ve only figured this out as the Kepler mission wrapped up its census of other planetary systems. 01:22: For example, in a planetary biosphere rather than floating in the void between the galaxies. 09:06: Our entire planetary system is pretty weird. 09:09: We’ve only figured this out as the Kepler mission wrapped up its census of other planetary systems. 01:22: For example, in a planetary biosphere rather than floating in the void between the galaxies. 09:09: We’ve only figured this out as the Kepler mission wrapped up its census of other planetary systems. 00:30: It shouldn’t be surprising that we live on a planet that can support our existence, in a universe that can produce such planets. 03:58: ... the Rare Earth hypothesis is a little more optimistic - it states that planets capable of spawning civilizations even at our own level are very ... 04:29: Earth-like planets are common. 04:31: ... by Earth-like I mean rocky planets about the size of the Earth in orbit around stars very similar to the ... 05:02: ... billions of planets stewing for billions of years - if only one civilization had a tiny head ... 05:12: Unless Earth has special qualities that mean true Earth-like planets are much rarer. 05:28: ... still not surprising for us to find ourselves on one of the very few planets with that ... 05:41: We’ll start by comparing planets of our solar system, because our ability to probe extra-solar planets is still in its infancy. 05:48: ... Earth has two qualities not shared by the other rocky planets in our solar system: 1) it has a very dynamic interior and 2) a very ... 09:23: ... contrast, the planets of most other systems tend to be all around the same size as each other ... 11:54: It’s very possible that a combination of extremely unlikely factors means it’s extremely rare for planets to spawn intelligence. 03:58: ... the Rare Earth hypothesis is a little more optimistic - it states that planets capable of spawning civilizations even at our own level are very ... 05:02: ... billions of planets stewing for billions of years - if only one civilization had a tiny head start ...
	2019-10-21: Is Time Travel Impossible? 01:34: So the original Planet of the Apes style time travel is possible. 05:59: And in fact we'd need entire planets – perhaps entire stars converted to negative energy to do this.
	2019-10-15: Loop Quantum Gravity Explained 00:16: ... scales of atoms and subatomic particles with that of the vast scales of planets, galaxies, and the entire ...
	2019-09-30: How Many Universes Are There? 14:56: Last time we visited that old argument - Is Pluto a planet? 15:06: And a number of you found the International Astronomy Union's new defition of planet - the one that excluded Pluto - not very scientific at all. 16:01: Here the IAU definition again: "A planet is a sun-orbiting body massive enough to be round and to have cleared it's orbit of debris". 16:42: If Earth formed at 100 times its current distance from the sun it wouldn't have cleared its orbit either, and so wouldn't be considered a planet. 16:55: ... mass and distance from the Sun that determines whether you get called a planet - and that relationship may not relate to any scientifically interesting ... 17:12: Within our solar system it's clear enough which are planets and which aren't by this definition. 17:22: That brings us to the first part of the IAU definition - a planet has to be orbiting our Sun. 17:29: That's right, other stars don't have planets - they have exoplanets. 17:33: The word planet is reserved exclusively for the 8 bodies of our solar system. 17:38: In fact you need this combination of requirements to know absolutely whether something is a planet by the new definition. 17:45: In general, the new definitely of planet avoids ambiguity but at the cost of arbitrariness - and you might also say of scientific usefulness. 15:06: And a number of you found the International Astronomy Union's new defition of planet - the one that excluded Pluto - not very scientific at all. 16:55: ... mass and distance from the Sun that determines whether you get called a planet - and that relationship may not relate to any scientifically interesting ... 17:45: In general, the new definitely of planet avoids ambiguity but at the cost of arbitrariness - and you might also say of scientific usefulness. 15:19: ... special props to Regolith on the spacetime discord, who's a bona fide planetary ... 15:37: ... definition is arbitrary and ambiguous, second that it should have been planetary scientists that made this decision, not ... 16:27: And that's an issue that planetary scientists take. 18:04: ... to change the definition again - perhaps this time with more input from planetary ... 15:19: ... special props to Regolith on the spacetime discord, who's a bona fide planetary ... 15:37: ... definition is arbitrary and ambiguous, second that it should have been planetary scientists that made this decision, not ... 16:27: And that's an issue that planetary scientists take. 18:04: ... to change the definition again - perhaps this time with more input from planetary ... 15:19: ... special props to Regolith on the spacetime discord, who's a bona fide planetary scientist. ... 15:37: ... definition is arbitrary and ambiguous, second that it should have been planetary scientists that made this decision, not ... 16:27: And that's an issue that planetary scientists take. 18:04: ... to change the definition again - perhaps this time with more input from planetary scientists. ... 17:12: Within our solar system it's clear enough which are planets and which aren't by this definition. 17:29: That's right, other stars don't have planets - they have exoplanets.
	2019-09-23: Is Pluto a Planet? 00:00: You know what a planet is, right? 00:15: And perhaps the word planet is too vague to be used as a scientific definition at all. 01:00: ... and how they're oriented, stars based on their color and brightness, and planets by… well, by a set of criteria that has caused more tension and ... 01:19: Because a change in that scheme demoted Pluto from planet to not-planet. 01:26: Today we’re going to settle whether this was reasonable, and whether we should keep the word “planet” at all. 01:32: The definition of “planet” has changed a lot. 01:36: If you were an ancient astronomer like say, Ptolemy, the planets were the asteres planetai, the wandering stars. 01:56: This definition of “planet” was the most sensible classification for thousands of years based on our observations and understanding of the universe. 02:07: ... the center of the universe and the Earth in its proper place among the planets. ... 02:34: The solar system finally made observational and theoretical sense: there were now 6 planets orbiting the sun in perfect mathematical harmony. 03:10: Uranus had been spotted many times throughout history, but was only identified as a planet after William Herschel recorded its movement in 1781. 03:39: Between these two discoveries, four other bodies joined the planets. 03:43: At the beginning of the 1800s Vesta, Juno, Ceres and Pallas were all spotted between the orbits of Mars and Jupiter and classified as planets. 04:05: You might argue that Ceres, Juno, Pallas, and Vesta were unfairly demoted from planet. 04:18: How many asteroids should we then classify as planets? 04:29: ... to evolve as our understanding of the solar system grew, and so the term planet was reserved for the now-familiar 8 - Mercury through Neptune, although ... 04:53: And so began a feverish search for yet another planet to resolve this discrepancy. 05:00: ... search for the so-called Planet X became the grail quest of Percival Lowell, businessman turned ... 05:12: In 1930, 14 years after Lowell’s death, but still powered by his observatory and his family’s fortune, Planet X was finally discovered. 05:37: ... of one of Slipher’s predictions for the location of the mysterious planet ... 05:48: ... were expecting a planet - and one was found roughly where they thought is should be - so perhaps ... 06:02: The orbit of this new object was far more elliptical - stretched out - than any other planet. 06:15: By 1931, astronomers had figured out that there didn’t need to be a ninth planet to account for Uranus’s strange orbit. 06:22: But because Pluto was the only such object yet discovered at that distance, it kept its classification as a planet. 06:30: New astronomy textbooks included distant Pluto and generations of students memorized 9 rather than 8 planets. 06:41: With the advent of giant telescopes and digital cameras, we began to find more and more objects that muddied the definition of “planet”. 06:54: ... their cores like a true star, but still seemed too massive to be called planets. ... 07:04: And yet some brown dwarfs orbit other, more massive stars just like planets do. 07:08: Our overly vague definition of “planet” left these brown dwarfs in taxonomical limbo. 07:41: Big enough to cling to its title of planet. 08:08: It’s 28% more massive than Pluto, which spurred NASA to initially hail it as the tenth planet. 08:28: If we classed them all as planets, schoolchildren would need a novella-length mnemonics to remember them all. 08:42: ... and definitions, met to finally define what it meant to be a planet in our solar ... 09:02: A planet must: One - be in its own orbit around the Sun, not around another planet like a moon. 09:27: Were it a proper planet, it would have collected or scattered all Kuiper belt objects in its orbit. 09:33: “Planet” got redefined to something that Pluto just isn’t. 09:38: ... this same process the IAU created an entire new class of object - dwarf planet - an object which has its own orbit and is spherical-ish, but not ... 09:51: Pluto, Eris, Ceres, Haumea, and Makemake were all promoted to dwarf planet, and many similar objects will no doubt follow. 10:02: While this definition was meant to settle the debate, some still argue that Pluto should be grandfathered in as a planet. 10:08: ... the current NASA Administrator, Jim Bridenstine, is declaring Pluto a planet once more saying “it’s the way I learned it.” Well, political appointees ... 10:37: Sure, we could add a fourth requirement to the definition of planet, like: 4: ignore all of the above if changing things makes people sad. 10:59: The reclassification from planet to dwarf planet DOES seem like a demotion. 11:46: As we’ve peered deeper into our universe, we’ve realized that it’s full of weird, beautiful, and important worlds, some we now call planets, some not. 12:06: And Pluto itself proved far more interesting than “just another planet”. 12:11: ... already knew about planets - but Pluto’s discovery revealed the existence of the Kuiper belt, which ... 12:24: Pluto went from being the least of the planets to one of the greatest of a new class of object. 12:31: And what about the term planet? 12:39: The inner, rocky planets are very different from the outer gaseous planets. 12:56: ... the new IAU definition of a planet, while being more precise, was somewhat tuned to a pre-determined desire ... 13:14: ... eight solar system bodies currently defined as planets certainly share plenty enough in common - similarities in the way they ... 13:33: Maybe at some point in the future, as we learn more about how different worlds form, astronomers will change the definition of planet again. 13:48: And anyway, the word “world” still applies to Pluto - and it's a rather more poetic label for one of the greatest dwarf planets in known spacetime. 14:53: David, in honour of your invaluable help we're naming a dwarf planet after you. 14:58: Dwarf planet David is a frigid, lifeless ball of ice and rock half the mass of Pluto and orbiting at the outer rim of the Kuiper belt. 15:56: ... structures would be much, much smaller than a planet and so presumably easier to protect from radiation and asteroids than ... 05:48: ... were expecting a planet - and one was found roughly where they thought is should be - so perhaps ... 09:38: ... this same process the IAU created an entire new class of object - dwarf planet - an object which has its own orbit and is spherical-ish, but not massive ... 14:58: Dwarf planet David is a frigid, lifeless ball of ice and rock half the mass of Pluto and orbiting at the outer rim of the Kuiper belt. 07:08: Our overly vague definition of “planet” left these brown dwarfs in taxonomical limbo. 01:36: If you were an ancient astronomer like say, Ptolemy, the planets were the asteres planetai, the wandering stars. 00:06: The surprisingly vicious debate over the planetary status of Pluto has given us a fascinating glimpse into what a scientific definition really is. 04:10: After all, Ceres is 20% the diameter of Mercury, so it’s in the planetary ballpark. 00:06: The surprisingly vicious debate over the planetary status of Pluto has given us a fascinating glimpse into what a scientific definition really is. 04:10: After all, Ceres is 20% the diameter of Mercury, so it’s in the planetary ballpark. 00:06: The surprisingly vicious debate over the planetary status of Pluto has given us a fascinating glimpse into what a scientific definition really is. 11:21: ... its own taxonomic status among a few classification-crazy bipeds several planetoids ... 01:00: ... and how they're oriented, stars based on their color and brightness, and planets by… well, by a set of criteria that has caused more tension and ... 01:36: If you were an ancient astronomer like say, Ptolemy, the planets were the asteres planetai, the wandering stars. 02:07: ... the center of the universe and the Earth in its proper place among the planets. ... 02:34: The solar system finally made observational and theoretical sense: there were now 6 planets orbiting the sun in perfect mathematical harmony. 03:39: Between these two discoveries, four other bodies joined the planets. 03:43: At the beginning of the 1800s Vesta, Juno, Ceres and Pallas were all spotted between the orbits of Mars and Jupiter and classified as planets. 04:18: How many asteroids should we then classify as planets? 06:30: New astronomy textbooks included distant Pluto and generations of students memorized 9 rather than 8 planets. 06:54: ... their cores like a true star, but still seemed too massive to be called planets. ... 07:04: And yet some brown dwarfs orbit other, more massive stars just like planets do. 08:28: If we classed them all as planets, schoolchildren would need a novella-length mnemonics to remember them all. 11:46: As we’ve peered deeper into our universe, we’ve realized that it’s full of weird, beautiful, and important worlds, some we now call planets, some not. 12:11: ... already knew about planets - but Pluto’s discovery revealed the existence of the Kuiper belt, which ... 12:24: Pluto went from being the least of the planets to one of the greatest of a new class of object. 12:39: The inner, rocky planets are very different from the outer gaseous planets. 12:56: ... tuned to a pre-determined desire - to eject Pluto and retain the 8 other planets. ... 13:14: ... eight solar system bodies currently defined as planets certainly share plenty enough in common - similarities in the way they ... 13:48: And anyway, the word “world” still applies to Pluto - and it's a rather more poetic label for one of the greatest dwarf planets in known spacetime. 12:11: ... already knew about planets - but Pluto’s discovery revealed the existence of the Kuiper belt, which ... 02:34: The solar system finally made observational and theoretical sense: there were now 6 planets orbiting the sun in perfect mathematical harmony. 08:28: If we classed them all as planets, schoolchildren would need a novella-length mnemonics to remember them all.
	2019-09-16: Could We Terraform Mars? 02:05: But even if the planet were warmer, liquid water would still be impossible in that thin atmosphere – it sublimates directly from ice to gas. 02:34: In the imaginations of sci-fi writers all we need to do is unlock the planet’s latent potential. 02:41: After all, Mars WAS once a warmer, watery planet with a much thicker atmosphere. 02:55: The hope then, is that this water and the atmosphere that once supported it is now all locked in the planet’s crust and ice caps. 03:28: The issue is that the planet is relatively puny. 07:35: So to get 10 tons of CO2 for every square meter on the surface of Mars you’d have to dig down over 10 meters – across the entire planet! 15:48: ... space explorers to imagine what role they can play to get us to the Red Planet. ... 18:06: ... its atmosphere creates an induced magnetic field that does protects the planet. ... 04:23: ... a nice Nature Astronomy article last year, planetary scientists Bruce Jakosky and Christopher Edwards calculate the ... 02:34: In the imaginations of sci-fi writers all we need to do is unlock the planet’s latent potential. 02:55: The hope then, is that this water and the atmosphere that once supported it is now all locked in the planet’s crust and ice caps. 02:34: In the imaginations of sci-fi writers all we need to do is unlock the planet’s latent potential.
	2019-09-03: Is Earth's Magnetic Field Reversing? 00:24: ... of magnetic force, forged by currents in the planet’s molten core, erupt from the surface close to the north south geographic ... 00:57: Not all planets are so lucky. 01:00: Mars, with its solid core, has no such shield – and so the red planet’s atmosphere was stripped away by the solar wind billions of years ago. 12:06: The field also becomes very messy – with mini north and south magnetic poles popping up across the surface of the planet. 00:24: ... of magnetic force, forged by currents in the planet’s molten core, erupt from the surface close to the north south geographic ... 00:57: Not all planets are so lucky. 01:00: Mars, with its solid core, has no such shield – and so the red planet’s atmosphere was stripped away by the solar wind billions of years ago. 00:24: ... of magnetic force, forged by currents in the planet’s molten core, erupt from the surface close to the north south geographic poles, ...
	2019-08-12: Exploring Arecibo in VR 180 00:00: We are somewhere very special for this week's episode. Check it out. It's the planet Earth! 00:13: ... rich biosphere you're seeing actually reads the entire planet including a staggering variety of living organisms Just recently, one ... 01:02: ... Arecibo is also a space radar that can bounce rate of pulses off planets and asteroids as far as Jupiter Or send messages to the stars. Let's ... 03:24: ... secondary antennas the receivers In fact Arecibo found the very first planet beyond our solar system and it's been central to the search for ... 00:00: We are somewhere very special for this week's episode. Check it out. It's the planet Earth! 03:24: ... is currently being planned we spoke to dr bill Mendes director of the planet habitability laboratory about finding exoplanets talking to aliens and Arecibo role ... 00:13: ... rich biosphere you're seeing actually reads the entire planet including a staggering variety of living organisms Just recently, one of those ... 01:02: ... Arecibo is also a space radar that can bounce rate of pulses off planets and asteroids as far as Jupiter Or send messages to the stars. Let's ...
	2019-07-25: Deciphering The Vast Scale of the Universe 00:05: For much of human history, people believed that the planet Earth was the center of the universe. 00:25: That’s a quadrillion stars, and as many planetary systems. 05:20: ... we'll need a little help from the Digital Universe built by the Hayden Planetarium at the American Museum of Natural ... 05:41: We're looking down at the Planetarium from the astrophysics department. 08:46: Knowledge that is revealed here at the Hayden Planetarium. 00:25: That’s a quadrillion stars, and as many planetary systems.
	2019-07-01: Thorium and the Future of Nuclear Energy 17:49: ... NASA isn't dedicating more resources to investigating all West themed planets in elliptical galaxies I don't know, Oppie. I just don't ...
	2019-06-20: The Quasar from The Beginning of Time 00:04: ... are volcanic rock, and this is one of the youngest patches of land on planet Earth, but that same geological event that built this land has provided ... 00:38: This is the tallest volcano on the planet. 01:10: ... like being on another planet. I can already feel the effect of the thinner atmosphere. My natural ... 00:04: ... are volcanic rock, and this is one of the youngest patches of land on planet Earth, but that same geological event that built this land has provided another ...
	2019-06-17: How Black Holes Kill Galaxies 05:24: ... they are 'Red and Dead' not because they contain lots of old west themed planets that's not yet known but rather, its because they appeared to have ...
	2019-05-09: Why Quantum Computing Requires Quantum Cryptography 13:42: We’ll show you how to construct a vast, planet-spanning network of encrypted quantum states real soon.
	2019-05-01: The Real Science of the EHT Black Hole 03:50: ... you build an interferometer that spans the planet Earth the wavelength you need in order to get this resolution is around ...
	2019-04-03: The Edge of an Infinite Universe 17:37: ... going to be an unpleasant period between the destruction of planet sized things and the destruction of atom sized things where you have the ...
	2019-03-28: Could the Universe End by Tearing Apart Every Atom? 10:03: ... enough to overcome Earth's own gravitational binding energy and the planet is disrupted. Moments later at the 10^-19 of a second, before absolute ...
	2019-03-20: Is Dark Energy Getting Stronger? 12:15: ... eventually it could cause the universe to expand inside galaxies, inside planetary systems, and eventually even inside ...
	2019-03-06: The Impossibility of Perpetual Motion Machines 06:36: Like a perfect Carnot engine, or a frictionless wheel – with or without magnets and mercury tubes – or a planet orbiting a star. 12:43: ... date of its close encounter with everyone's favorite Kuiper Belt dwarf planet. ... 06:36: Like a perfect Carnot engine, or a frictionless wheel – with or without magnets and mercury tubes – or a planet orbiting a star.
	2018-12-20: Why String Theory is Wrong 16:28: ... by something fundamental about our universe if DNA forms on another planet is it always right-handed would a parity reflected universe always have ...
	2018-12-12: Quantum Physics in a Mirror Universe 00:02: ... these seeds could be at least somewhat targeted to star systems or even planets depending on assumptions evolving a technological civilization to the ...
	2018-12-06: Did Life on Earth Come from Space? 00:37: ... Luther panspermia basically be attached to a rock that travels between planets now we know that debris from planetary surfaces can be ejected into ...
	2018-11-21: 'Oumuamua Is Not Aliens 14:00: ... high energy neutrinos aren't expected to make it all the way through the planet, hence the surprise at seeing the decay products of a high energy tau ... 14:15: Neutrinos have no trouble passing through the planet whatever their energy. 15:00: So it's not that neutrinos don't make it through the planet. 02:26: ... the stars, probably ejected in the violent early stages of formation of planetary ... 08:44: And by that I mean the expected density of space rocks that are ejected during the planetary formation process. 02:26: ... the stars, probably ejected in the violent early stages of formation of planetary ... 08:44: And by that I mean the expected density of space rocks that are ejected during the planetary formation process. 02:26: ... the stars, probably ejected in the violent early stages of formation of planetary systems. ...
	2018-11-14: Supersymmetric Particle Found? 03:34: Build an accelerator the size of the planet, the solar system, give up and let theorists just tell their stories? 07:13: They should not come from directly below, which would require them to pass through the entire planet. 07:29: ... by a high energy particle passing all the way through the middle of the planet. ... 09:07: A stau particle was produced on the opposite side of the planet by an incoming ultra high energy neutrino plowing into the earth. 11:21: They may have been boring or muon neutrinos that can easily pass through the planet.
	2018-10-25: Will We Ever Find Alien Life? 01:55: This number allows us to figure out the fraction of stars that have planets. 02:01: It also allows us to figure out that there are something like 40 billion habitable planets in the Milky Way. 02:07: By habitable, I mean rocky planets the right distance from their star to have liquid water. 02:14: The Transiting Planet Survey Satellite is now in orbit and taking over from Kepler. 02:20: It'll find something like 20,000 new worlds, telling us once and for all how common earth-like planets really are. 02:26: And how many of these planets have life? 02:48: We can't see this effect on earth-like planets yet, but the James Webb Space Telescope to launch in a year or so will get close to doing so. 08:17: ... found that, as long as the odds of any given habitable planet spawning a technological species is greater than 1 in 60 billion, then ... 09:12: But remember, it's only for the planets not wiped clean by gamma ray burst. 09:44: ... watery planets may be abundant, but maybe there's a step in that slow evolutionary ... 10:28: ... wrap up, let's consider the possibility that lots of planets produce civilizations at around our level and they wipe themselves out ... 12:05: But I should also point out that this same massive access to technology that could kill us may also get humanity off the earth and onto other planets. 08:17: ... found that, as long as the odds of any given habitable planet spawning a technological species is greater than 1 in 60 billion, then humanity ... 02:14: The Transiting Planet Survey Satellite is now in orbit and taking over from Kepler. 12:25: Are we more inclined to acts of self-destruction and planetary sabotage or to acts of preservation and exploration? 01:55: This number allows us to figure out the fraction of stars that have planets. 02:01: It also allows us to figure out that there are something like 40 billion habitable planets in the Milky Way. 02:07: By habitable, I mean rocky planets the right distance from their star to have liquid water. 02:20: It'll find something like 20,000 new worlds, telling us once and for all how common earth-like planets really are. 02:26: And how many of these planets have life? 02:48: We can't see this effect on earth-like planets yet, but the James Webb Space Telescope to launch in a year or so will get close to doing so. 09:12: But remember, it's only for the planets not wiped clean by gamma ray burst. 09:44: ... watery planets may be abundant, but maybe there's a step in that slow evolutionary ... 10:28: ... wrap up, let's consider the possibility that lots of planets produce civilizations at around our level and they wipe themselves out ... 12:05: But I should also point out that this same massive access to technology that could kill us may also get humanity off the earth and onto other planets. 10:28: ... wrap up, let's consider the possibility that lots of planets produce civilizations at around our level and they wipe themselves out with such ...
	2018-09-12: How Much Information is in the Universe? 00:25: ... there's all the stuff that isn't stars-- the dark matter, black holes, planets, and the particles, and radiation in between the stars and galaxies, not ...
	2018-08-30: Is There Life on Mars? 00:43: ... the Red Planet, fourth rock from the sun, it's currently just past its closest approach ... 00:53: This is a planet that, as far as we know, is inhabited entirely by robots. 04:05: ... observed streaks on the surface of the planet that he named "canali." That's Italian for "channels," presumably ... 05:00: ... from the polar ice caps as a last-ditch source of water on a drying planet. ... 05:40: In the 1960s and early '70s the Mariner missions conducted the first Mars flybys, giving us our very first close-ups of the planet. 07:08: ... Mars's gravitational field after another space rock smashed into the planet. ... 08:14: They inspired our continued obsession with the Red Planet, and so many more missions have followed. 09:47: The vast Martian dust storm that has enveloped the planet since early June caused "Opportunity" to enter hibernation mode. 12:53: But the planet was certainly wet and hospitable for long enough. 13:07: ... even one incident of life beginning on another planet would tell us worlds about the likelihood of life in the universe-- kind ... 00:43: ... the Red Planet, fourth rock from the sun, it's currently just past its closest approach to ... 02:53: Nonetheless, the prospect of a watery Mars kicked off centuries of optimism for an inhabited planetary neighborhood. 10:29: Our latest Martian explorer, the "Curiosity" rover, has sampled soil at lower latitudes and confirmed the presence of H2O in the soil planet-wide.
	2018-08-23: How Will the Universe End? 04:49: As stars randomly pass close to each other, planets are flung into the blackness. 05:19: The remnants, mostly black dwarfs but also the diaspora of frozen planets and similar substellar objects, will be flung out of the galaxy. 06:53: That means all of the planets, black dwarfs, space dust, everything. 09:35: But smaller stellar remnants, ancient planets, asteroids, et cetera, could persist. 04:23: Believe it or not, many of those black dwarfs will still have planetary systems from their days as regular stars. 04:40: The next destructive event is that every planetary system in the galaxy will eventually be disrupted by close encounters between stellar remnants. 04:54: It'll take something like 1,000 trillion years, 10 to the power of 15 years, for, essentially, all planetary systems to be obliterated in this way. 04:23: Believe it or not, many of those black dwarfs will still have planetary systems from their days as regular stars. 04:40: The next destructive event is that every planetary system in the galaxy will eventually be disrupted by close encounters between stellar remnants. 04:54: It'll take something like 1,000 trillion years, 10 to the power of 15 years, for, essentially, all planetary systems to be obliterated in this way. 04:23: Believe it or not, many of those black dwarfs will still have planetary systems from their days as regular stars. 04:54: It'll take something like 1,000 trillion years, 10 to the power of 15 years, for, essentially, all planetary systems to be obliterated in this way. 04:49: As stars randomly pass close to each other, planets are flung into the blackness. 05:19: The remnants, mostly black dwarfs but also the diaspora of frozen planets and similar substellar objects, will be flung out of the galaxy. 06:53: That means all of the planets, black dwarfs, space dust, everything. 09:35: But smaller stellar remnants, ancient planets, asteroids, et cetera, could persist. 06:53: That means all of the planets, black dwarfs, space dust, everything.
	2018-08-15: Quantum Theory's Most Incredible Prediction 03:06: ... in circles, for example, a loop of wire with an electric current or the planet Earth with its dynamo ...
	2018-08-01: How Close To The Sun Can Humanity Get? 02:24: Auroras normally only visible near the poles were witnessed across the entire planet. 06:59: But instead of sling-shotting around planets to increase speed, Parker will do multiple flybys of Venus to reduce speed. 07:38: ... Parker will get roughly 10 times closer to the sun than the closest planet. ... 06:59: But instead of sling-shotting around planets to increase speed, Parker will do multiple flybys of Venus to reduce speed.
	2018-06-27: How Asteroid Mining Will Save Earth 02:25: They are the stuff of the terrestrial planets, the building blocks of worlds like the Earth that never managed to pull themselves together. 08:45: It was one of the few missions that had a clear track to massive potential profits and saving the planet from asteroid impact. 00:26: ... the banner of a new company, Planetary Resources, they would mine asteroids for their precious resources and ... 04:40: ... Planetary Resources company estimates that a single 30-meter asteroid may contain ... 07:24: This asteroid prospecting is the current focus of effort for Planetary Resources and its competitors. 07:46: Planetary Resources is developing its Arkyd spacecraft with that initial goal. 00:26: ... the banner of a new company, Planetary Resources, they would mine asteroids for their precious resources and ... 04:40: ... Planetary Resources company estimates that a single 30-meter asteroid may contain ... 07:24: This asteroid prospecting is the current focus of effort for Planetary Resources and its competitors. 07:46: Planetary Resources is developing its Arkyd spacecraft with that initial goal. 00:26: ... the banner of a new company, Planetary Resources, they would mine asteroids for their precious resources and perhaps save ... 04:40: ... Planetary Resources company estimates that a single 30-meter asteroid may contain $30 ... 07:24: This asteroid prospecting is the current focus of effort for Planetary Resources and its competitors. 07:46: Planetary Resources is developing its Arkyd spacecraft with that initial goal. 04:40: ... Planetary Resources company estimates that a single 30-meter asteroid may contain $30 billion in ... 02:25: They are the stuff of the terrestrial planets, the building blocks of worlds like the Earth that never managed to pull themselves together.
	2018-05-23: Why Quantum Information is Never Destroyed 10:33: So it's springtime, at least on this half of the planet, and you know what that means-- spring break.
	2018-05-09: How Gaia Changed Astronomy Forever 06:00: For example, this is the field of stars of the planet hunting, Kepler telescope. 06:14: We can now study the kinematics of stars that have cumulatively, thousands of confirmed planets. 06:27: ... of those stars, and thus, also get better measures of the sizes of the planets around ... 06:46: We can even potentially, detect exoplanets by looking at the star's radial velocities and measuring shifts to a planet tugging on the star. 06:00: For example, this is the field of stars of the planet hunting, Kepler telescope. 06:46: We can even potentially, detect exoplanets by looking at the star's radial velocities and measuring shifts to a planet tugging on the star. 06:38: Based on the new data, we've already been able to confirm a gap in planetary radius size, at around 1.9 Earth radius. 06:14: We can now study the kinematics of stars that have cumulatively, thousands of confirmed planets. 06:27: ... of those stars, and thus, also get better measures of the sizes of the planets around ...
	2018-05-02: The Star at the End of Time 08:20: Those planets will thaw as their star brightens and may enjoy billions of years of stable warmth. 07:32: We know that red dwarfs do have planetary systems. 08:20: Those planets will thaw as their star brightens and may enjoy billions of years of stable warmth.
	2018-04-25: Black Hole Swarms 01:49: Dense elements, like iron, sink to the centers of forming planetary bodies in a process called differentiation.
	2018-04-18: Using Stars to See Gravitational Waves 02:54: Observatories across the planet and in orbit around the planet swiveled to watch the afterglow of this collision.
	2018-04-11: The Physics of Life (ft. It's Okay to be Smart & PBS Eons!) 10:10: ... random possible state, little eddies of order, like galaxies, stars, planets, and life naturally ...
	2018-03-28: The Andromeda-Milky Way Collision 07:13: No, our planetary system will probably survive this encounter.
	2018-03-21: Scientists Have Detected the First Stars 03:31: This is one of the most radio quiet locations on the planet, far from any human-made interference.
	2018-03-07: Should Space be Privatized? 05:01: ... mysteries of our cosmos and keep a watchful eye on our own fragile planet. ... 05:14: We've sent probes to every planet in our solar system and landed on several, but not a single CEO got rich doing it.
	2018-02-21: The Death of the Sun 02:01: But what are the prospects for our little planet after the sun runs out of fuel? 07:42: In that case, the entire planet may have vaporized. 08:32: All the planet's orbits will have expanded, and to the moons of Neptune, Uranus, and even Saturn, may provide brief refuge. 09:18: ... ride on rockets and rent sports cars and, perhaps, safer vessels to the planets and even to the ... 09:57: ... bound into the system, whether the system be an atomic nucleus or a planet, and whatever that type of energy ... 07:02: Explosions of runaway fusion in the double burning shell blast away the outer layers, perhaps creating a beautiful planetary nebula. 08:32: All the planet's orbits will have expanded, and to the moons of Neptune, Uranus, and even Saturn, may provide brief refuge. 09:18: ... ride on rockets and rent sports cars and, perhaps, safer vessels to the planets and even to the ... 08:32: All the planet's orbits will have expanded, and to the moons of Neptune, Uranus, and even Saturn, may provide brief refuge.
	2018-02-14: What is Energy? 12:19: In our recent Space Time journal club, we talked about the discovery of the amazing Chronos, the planet eating star. 12:58: ... points out that 15 Earth masses of terrestrial material is a lot a planet for a star to consume, at least compared to our solar system, which only ... 13:20: The Trappist 1 system has seven planets all close to or larger than the Earth. 13:30: Well, solar system formation models do indicate a scenario in which our sun may have swallowed some early terrestrial planets. 13:45: That could have sent a new generation of planets spiraling into the sun. 13:49: The remaining protoplanetary debris was only just enough to form a few planets that we see today. 12:19: In our recent Space Time journal club, we talked about the discovery of the amazing Chronos, the planet eating star. 13:20: The Trappist 1 system has seven planets all close to or larger than the Earth. 13:30: Well, solar system formation models do indicate a scenario in which our sun may have swallowed some early terrestrial planets. 13:45: That could have sent a new generation of planets spiraling into the sun. 13:49: The remaining protoplanetary debris was only just enough to form a few planets that we see today. 13:45: That could have sent a new generation of planets spiraling into the sun.
	2018-01-31: Kronos: Devourer Of Worlds 00:00: ... recently discovered a star that appears to have consumed its own planets like some sort of infanticidal titan from Greek ... 05:24: The extra elements found in Kronos are pretty much exactly what you'd expect from a star nomming on a bunch of terrestrial planets. 05:32: Terrestrial, or rocky, planets are made of elements with high condensation temperatures. 05:42: Volatiles are less abundant in those inner rocky planets. 05:54: The researchers tested the hypothesis by throwing a bunch of Earth-like planets into a sun-like star-- mathematically, I mean. 07:02: Well, computer simulations of planet formation do show that planets can fall into their home stars. 07:08: ... part of the system, either by migration due to interactions between planets or if the gas giant is perturbed by a passing star into an elliptical ... 07:25: Future Gaia data will be used to search for rampaging outer planets around Kronos. 07:30: And it may also reveal other planet-eating stars, which will shed light on the whole planet formation process. 07:02: Well, computer simulations of planet formation do show that planets can fall into their home stars. 07:30: And it may also reveal other planet-eating stars, which will shed light on the whole planet formation process. 05:10: Just like its mythological namesake, perhaps Kronos ate its children, perhaps the extra elements of the vaporized remains of its own planetary system. 06:01: The Princeton research ethics policies are strict about actual planetary destruction. 06:33: ... sometime well after its formation and after the formation of any planetary ... 05:10: Just like its mythological namesake, perhaps Kronos ate its children, perhaps the extra elements of the vaporized remains of its own planetary system. 06:01: The Princeton research ethics policies are strict about actual planetary destruction. 06:33: ... sometime well after its formation and after the formation of any planetary ... 06:01: The Princeton research ethics policies are strict about actual planetary destruction. 07:30: And it may also reveal other planet-eating stars, which will shed light on the whole planet formation process. 00:00: ... recently discovered a star that appears to have consumed its own planets like some sort of infanticidal titan from Greek ... 05:24: The extra elements found in Kronos are pretty much exactly what you'd expect from a star nomming on a bunch of terrestrial planets. 05:32: Terrestrial, or rocky, planets are made of elements with high condensation temperatures. 05:42: Volatiles are less abundant in those inner rocky planets. 05:54: The researchers tested the hypothesis by throwing a bunch of Earth-like planets into a sun-like star-- mathematically, I mean. 07:02: Well, computer simulations of planet formation do show that planets can fall into their home stars. 07:08: ... part of the system, either by migration due to interactions between planets or if the gas giant is perturbed by a passing star into an elliptical ... 07:25: Future Gaia data will be used to search for rampaging outer planets around Kronos.
	2018-01-24: The End of the Habitable Zone 05:48: But planet surface temperature and the location of the habitable zone depends on the planet's atmosphere as well as the star's brighteners. 06:31: And depending on how our atmosphere evolves, our beautiful blue orb may become a desert planet relatively soon. 05:48: But planet surface temperature and the location of the habitable zone depends on the planet's atmosphere as well as the star's brighteners.
	2018-01-10: What Do Stars Sound Like? 02:34: ... seismic waves are generated by earthquakes and can travel around the planet as longitudinal pressure, or p-waves; transverse shear, or s-waves; and ... 07:39: While Kepler does asteroseismology as a side gig to finding alien planets. 07:45: Future planet hunting satellites, like Tess and Plato, will continue this work with higher precision and for many more stars. 07:39: While Kepler does asteroseismology as a side gig to finding alien planets.
	2017-12-20: Extinction by Gamma-Ray Burst 00:06: The cosmos has so many catastrophes in store for our fragile, little planet. 02:58: Any planet within a few tens of light years of a supernova is in trouble.
	2017-12-13: The Origin of 'Oumuamua, Our First Interstellar Visitor 02:46: Or it could be the flickering exhaust jets of an alien scout ship returning to report a planet ripe for invasion. 06:28: In planet formation models, lots of chunks of matter, and even some planets, get ejected from the relatively violent protoplanetary disk. 02:46: Or it could be the flickering exhaust jets of an alien scout ship returning to report a planet ripe for invasion. 04:50: But perhaps Oumuamua got some sort of gravitational kick from an unknown planetary body. 09:00: In the meantime, it joins its countless interstellar cousins, orphaned planetary debris, stretching across the reaches of space time. 04:50: But perhaps Oumuamua got some sort of gravitational kick from an unknown planetary body. 09:00: In the meantime, it joins its countless interstellar cousins, orphaned planetary debris, stretching across the reaches of space time. 04:50: But perhaps Oumuamua got some sort of gravitational kick from an unknown planetary body. 09:00: In the meantime, it joins its countless interstellar cousins, orphaned planetary debris, stretching across the reaches of space time. 06:28: In planet formation models, lots of chunks of matter, and even some planets, get ejected from the relatively violent protoplanetary disk.
	2017-12-06: Understanding the Uncertainty Principle with Quantum Fourier Series 13:13: ... stars for the characteristic dips in brightness due to transiting alien planets. ...
	2017-11-29: Citizen Science + Zero-Point Challenge Answer 01:38: Shoemaker, in particular, was incredibly active, discovering or co-discovering 32 comets, 377 minor planets, and over 800 asteroids. 03:53: ... supernovae or looking for gravitational wave signals in LIGO and finding planets forming in the debris disks of new solar ... 04:15: The newest Zooniverse project is called Backyard Worlds-- Planet 9. 04:19: ... goal is to search beyond Neptune for the potential ninth planet, as well as looking for brown dwarfs-- cool, faint, failed stars-- that ... 04:30: The project has located nearby brown dwarves, but citizens are still searching for Planet Nine. 04:15: The newest Zooniverse project is called Backyard Worlds-- Planet 9. 01:38: Shoemaker, in particular, was incredibly active, discovering or co-discovering 32 comets, 377 minor planets, and over 800 asteroids. 03:53: ... supernovae or looking for gravitational wave signals in LIGO and finding planets forming in the debris disks of new solar ...
	2017-11-22: Suicide Space Robots 01:48: ... enough to make the first ever transmission from the surface of another planet-- accurate temperature and pressure readings of the atmosphere that killed ... 05:49: ... a sacrifice had to be made by decree of NASA's awesomely named Office of Planetary ... 06:13: The Planetary Protection Agency has issued death sentences in the past. 06:42: Some of the most mysterious entities in our solar system are the comets that dwell in the Kuiper Belt far outside our planetary system. 05:49: ... a sacrifice had to be made by decree of NASA's awesomely named Office of Planetary ... 06:13: The Planetary Protection Agency has issued death sentences in the past. 06:42: Some of the most mysterious entities in our solar system are the comets that dwell in the Kuiper Belt far outside our planetary system. 05:49: ... a sacrifice had to be made by decree of NASA's awesomely named Office of Planetary Protection. ... 06:13: The Planetary Protection Agency has issued death sentences in the past.
	2017-11-02: The Vacuum Catastrophe 03:49: ... density would contain enough energy to boil all of the oceans on the planet, yet even if vacuum energy did have a value this high-- in fact, even if ...
	2017-10-25: The Missing Mass Mystery 02:38: It's the stuff of stars, planets, gas, dust, you, me.
	2017-10-04: When Quasars Collide STJC 03:59: ... the target is observed with radio telescopes on opposite sides of the planet, and phase differences in the incoming radio waves are used to find the ... 00:08: Red giant stars incinerate planetary systems, but neutron stars cannibalize their red giant neighbors.
	2017-09-28: Are the Fundamental Constants Changing? 10:25: ... we find ourselves in a part of the universe conducive to stars, and to planets, and to ...
	2017-09-20: The Future of Space Telescopes 01:14: ... Kepler mission has determined that terrestrial planets-- that is, rocky planets like our Earth-- are extremely common and may ... 01:22: But these planets are extremely difficult to directly image because they are dense and small. 01:27: ... higher temperature than volatiles, like ammonia and water, terrestrial planets tend to form close to their parent ... 01:49: So how can we find a terrestrial planet around a star light years away? 01:58: ... inside a telescope that occludes a star, blocking its light so that any planets can be seen more ... 03:46: The main motivation for building starshades is to suppress the glare of stars enough to see the planets that orbit them. 04:08: There are a couple of thousand stars within that range, and hundreds of sun-like stars, many of which certainly have Earth-like planets. 07:41: ... outwards, it could spot a terrestrial planet at tens of light years distance and even map the cloud structure of a ... 01:14: ... Kepler mission has determined that terrestrial planets-- that is, rocky planets like our Earth-- are extremely common and may ... 01:22: But these planets are extremely difficult to directly image because they are dense and small. 01:27: ... higher temperature than volatiles, like ammonia and water, terrestrial planets tend to form close to their parent ... 01:58: ... inside a telescope that occludes a star, blocking its light so that any planets can be seen more ... 03:46: The main motivation for building starshades is to suppress the glare of stars enough to see the planets that orbit them. 04:08: There are a couple of thousand stars within that range, and hundreds of sun-like stars, many of which certainly have Earth-like planets. 01:27: ... higher temperature than volatiles, like ammonia and water, terrestrial planets tend to form close to their parent ...
	2017-09-13: Neutron Stars Collide in New LIGO Signal? 12:22: ... we've made arrangements for half a planet's worth of gold from the next neutron star merger to be shipped directly ... 14:10: That method is to watch the effect on the parent stars' light as it passes through the planet's atmosphere. 14:16: And for that to happen, the planet needs to pass directly in front of its star from our perspective. 14:30: On the other hand, the TRAPPIST-1 planets are perfectly aligned for this. 14:38: ... which can measure the tiny wobble in a star's motion caused by the planet's gravitational ... 14:22: Only a small fraction of planetary systems are conveniently aligned so as to do that, and the Proxima Cen system isn't one of them. 12:22: ... we've made arrangements for half a planet's worth of gold from the next neutron star merger to be shipped directly ... 14:10: That method is to watch the effect on the parent stars' light as it passes through the planet's atmosphere. 14:30: On the other hand, the TRAPPIST-1 planets are perfectly aligned for this. 14:38: ... which can measure the tiny wobble in a star's motion caused by the planet's gravitational ... 14:10: That method is to watch the effect on the parent stars' light as it passes through the planet's atmosphere. 14:38: ... which can measure the tiny wobble in a star's motion caused by the planet's gravitational ... 12:22: ... we've made arrangements for half a planet's worth of gold from the next neutron star merger to be shipped directly to your ...
	2017-08-24: First Detection of Life 00:12: To detect life on a planet based on measurements by a space probe. 00:22: That planet? 01:35: ... probably the first-- way we'll spot alien life is by its effect on its planet's atmosphere-- in particular, the chemical content of that ... 02:31: While some of these molecules are known to arise from life on Earth, their presence isn't enough to confirm life on another planet. 07:26: To be more precise, we analyze the light of a distant star as it passes through the atmosphere of one of its planets. 07:42: ... a tiny fraction of the star's light passes through the planet's atmosphere when this happens, but by carefully subtracting most of the ... 08:16: However, given the planet's blazing 700 degree Celsius surface, it's unlikely that extraterrestrial life would be found. 08:45: We don't quite have the technology to analyze an Earth-like atmosphere around an Earth-like planet. 08:51: Those planets are just too small and their atmospheres too thin for any current telescope. 09:46: Now, there are other reasons to think that the TRAPPIST-1 planets are not ideal for life, but who knows. 09:57: There are billions and billions of potentially water-bearing Earth-like planets in our galaxy alone. 10:31: Perhaps that answer is already traveling to us in the light of a distant planet's atmosphere calling to us from across spacetime. 00:12: To detect life on a planet based on measurements by a space probe. 07:42: ... the star's light, we're left with a set of absorption features from the planetary atmosphere ... 01:35: ... probably the first-- way we'll spot alien life is by its effect on its planet's atmosphere-- in particular, the chemical content of that ... 07:26: To be more precise, we analyze the light of a distant star as it passes through the atmosphere of one of its planets. 07:42: ... a tiny fraction of the star's light passes through the planet's atmosphere when this happens, but by carefully subtracting most of the ... 08:16: However, given the planet's blazing 700 degree Celsius surface, it's unlikely that extraterrestrial life would be found. 08:51: Those planets are just too small and their atmospheres too thin for any current telescope. 09:46: Now, there are other reasons to think that the TRAPPIST-1 planets are not ideal for life, but who knows. 09:57: There are billions and billions of potentially water-bearing Earth-like planets in our galaxy alone. 10:31: Perhaps that answer is already traveling to us in the light of a distant planet's atmosphere calling to us from across spacetime. 01:35: ... probably the first-- way we'll spot alien life is by its effect on its planet's atmosphere-- in particular, the chemical content of that ... 07:42: ... a tiny fraction of the star's light passes through the planet's atmosphere when this happens, but by carefully subtracting most of the star's ... 10:31: Perhaps that answer is already traveling to us in the light of a distant planet's atmosphere calling to us from across spacetime. 08:16: However, given the planet's blazing 700 degree Celsius surface, it's unlikely that extraterrestrial life would be found.
	2017-08-16: Extraterrestrial Superstorms 00:22: The great vortices of the Jovian planets are true storms, analogous in many ways to Earth's hurricanes. 00:31: For example, these storms are as big as entire planets. 00:34: ... Spot, stretching an incredible two to three times the diameter of the planet ... 04:09: They are most often anti-cyclonic, high-pressure systems and are powered not by the sun, but by the collapse of the planet itself. 04:18: See, the planet's never quite finished forming. 05:29: But on the gas giants, it can extend 100 miles into the planet's murky depths, where pressure forces the gas into a metallic liquid state. 00:34: ... Spot, stretching an incredible two to three times the diameter of the planet Earth. ... 00:06: ... but even the most powerful hurricanes are a breeze compared to the great planet-sized tempests of the gas ... 00:22: The great vortices of the Jovian planets are true storms, analogous in many ways to Earth's hurricanes. 00:31: For example, these storms are as big as entire planets. 04:18: See, the planet's never quite finished forming. 05:29: But on the gas giants, it can extend 100 miles into the planet's murky depths, where pressure forces the gas into a metallic liquid state. 00:06: ... but even the most powerful hurricanes are a breeze compared to the great planet-sized tempests of the gas ...
	2017-08-02: Dark Flow 00:26: Planets orbit stars. 01:57: Actually, when we look at the CMB from our moving platform of planet Earth, we don't see a perfectly even temperature. 00:26: Planets orbit stars.
	2017-07-19: The Real Star Wars 00:50: The United Federation of Planets was just around the corner.
	2017-05-31: The Fate of the First Stars 08:20: They produced the first heavy elements that would someday become dust and new stars and planets and-- well-- us.
	2017-05-17: Martian Evolution 00:19: Human populations on other planets may quickly evolve into things that look nothing like humans as we know them. 00:58: But if those challenges are met, we may reach a time when many generations of humans have lived and died on the red planet. 10:31: ... be the first in a long line of descendent species that spread their way planet to planet, then star to star across the reaches of space ... 00:19: Human populations on other planets may quickly evolve into things that look nothing like humans as we know them.
	2017-05-10: The Great American Eclipse 06:35: A little further away, you'll see the planets Venus, Mars, Jupiter, and the elusive Mercury. 07:34: As totality fades, Leo, Orion, the planets and the corona disappear in midday twilight. 06:35: A little further away, you'll see the planets Venus, Mars, Jupiter, and the elusive Mercury. 07:34: As totality fades, Leo, Orion, the planets and the corona disappear in midday twilight. 06:35: A little further away, you'll see the planets Venus, Mars, Jupiter, and the elusive Mercury.
	2017-05-03: Are We Living in an Ancestor Simulation? ft. Neil deGrasse Tyson 06:40: ... uses Robert Bradbury's estimate-- that a computer the size of a large planet, a so-called Jupiter brain, would be capable of performing 10 to the ... 08:31: We're on a typical planet around a typical star in a typical galaxy, with one exception. 00:29: ... I recently had about this idea with my colleague at the Hayden Planetarium in New York ...
	2017-04-26: Are You a Boltzmann Brain? 05:16: ... by that increase in entropy includes the formation of galaxies, stars, planets, Alan Tudyk-- indeed, the entire process of ... 06:06: ... that we view the universe from the comfy biosphere of a terrestrial planet, even though the volume of all biospheres is minuscule compared to the ... 05:16: ... by that increase in entropy includes the formation of galaxies, stars, planets, Alan Tudyk-- indeed, the entire process of ...
	2017-03-15: Time Crystals! 02:49: Cups of coffee cool down, planets orbit the sun, the universe expands. 02:54: But cups of coffee in the universe are not in equilibrium, and the planets are macroscopic moving objects. 10:45: Solano Felicio asks about the possibility of stable orbits when planets are so close together. 10:55: The planet's orbital periods have evolved so that each pair of planets lines up at regular intervals. 11:07: ... finding this nice resonant configuration, and that probably drove the planets from much larger orbits to their current locations very close to the ... 11:47: That gives you an idea of the average probability of alignment, but not all of those will have planets. 11:54: Yet it's estimated that a system with an Earth-like planet orbiting a Sun-like star has around a 1% chance of transiting from our perspective. 11:18: Matthew Pick asks about the transit method, and wonders how rare it is for a planetary system to be lined up so we actually see the transit. 11:31: The Kepler Space Telescope has so far discovered 2,330 confirmed exoplanets in 578 planetary systems. 11:18: Matthew Pick asks about the transit method, and wonders how rare it is for a planetary system to be lined up so we actually see the transit. 11:31: The Kepler Space Telescope has so far discovered 2,330 confirmed exoplanets in 578 planetary systems. 02:49: Cups of coffee cool down, planets orbit the sun, the universe expands. 02:54: But cups of coffee in the universe are not in equilibrium, and the planets are macroscopic moving objects. 10:45: Solano Felicio asks about the possibility of stable orbits when planets are so close together. 10:55: The planet's orbital periods have evolved so that each pair of planets lines up at regular intervals. 11:07: ... finding this nice resonant configuration, and that probably drove the planets from much larger orbits to their current locations very close to the ... 11:47: That gives you an idea of the average probability of alignment, but not all of those will have planets. 10:55: The planet's orbital periods have evolved so that each pair of planets lines up at regular intervals. 02:49: Cups of coffee cool down, planets orbit the sun, the universe expands. 10:55: The planet's orbital periods have evolved so that each pair of planets lines up at regular intervals.
	2017-03-08: The Race to a Habitable Exoplanet - Time Warp Challenge 02:04: A race to a newly found habitable planet 100 light years away. 02:17: An evil interplanetary corporation is intent on strip mining the planet to oblivion. 02:04: A race to a newly found habitable planet 100 light years away.
	2017-03-01: The Treasures of Trappist-1 00:10: A nearby red dwarf star was discovered to have not one, but seven Earth-like planets, and any of them may be capable of supporting life. 00:19: ... and team and reported in the journal, "Nature." The discovery of three planets in the system was made in 2015, with the Transiting Planets and ... 00:43: Follow up with the Spitzer Space Telescope has now revealed an additional four planets. 00:48: Both telescopes use the transit method, watching for the dimming of the central star as the planets pass in front of it. 00:56: Never before have we seen so many Earth-like planets in one place. 01:26: The seven planets huddle extremely close to this star-- all within one fifth of Mercury's orbit. 01:33: That makes a year on a TRAPPIST-1 planet very short, from a day and a half on the innermost TRAPPIST-1b to three weeks on TRAPPIST-1h. 01:45: The planets live so close together that they all tug on each other gravitationally. 02:13: ... planets have now settled into stable orbital resonances with each other, and ... 02:22: It's also unlikely that enough material resources would have been available for so much planet forming so close to the star. 02:30: ... different chemicals condense at different temperatures, planets' distance from the star during formation largely determines the planet's ... 02:46: Maybe the TRAPPIST-1 planets started out as mixtures of rock and ice. 02:50: However, three of them now occupy their star's habitable zone, where planet's surface temperature would be just right for liquid water. 03:23: But in that densely packed system, it covers three of the planets. 03:29: ... have done some climate modeling, which indicate that the three innermost planets may be more Venusian, so overheated due to a runaway greenhouse ... 03:43: The outermost planet, which orbits past the snow line, should be icy. 03:48: ... and generated by tidal interactions with its star and the other planets could warm it to liquid water temperatures as ... 03:59: In fact, any of the seven planet could host liquid water. 04:27: See, because the planets are so close to the star, they're probably tidally locked, like our moon. 04:33: One side of each planet will always face the star, the other away. 04:47: These planets would be huge in each other's skies. 05:04: Partial eclipses of the central star by sister planets may be common, but there would be no full eclipses. 05:10: ... 5 and 1/2 degrees on the sky if you're standing on the innermost planet, and a degree on the sky for the ... 05:29: On the inner planets' sunny side, the star will provide about as much visible light as our sun. 05:35: Planets further out will receive less light, but the star's infrared intensity provides the heat needed for liquid water. 05:48: Being so close to the central star exposes the planets to stellar activity. 06:01: But within a tenth of an AU of TRAPPIST-1a, CMEs would be dangerous, and tidal locking would weaken the planet's protective magnetospheres. 06:12: The TRAPPIST-1a's winds may have eroded its planet's atmospheres, just as the sun did with Mars. 06:34: We don't yet know much about what those planet's atmospheres are like. 06:50: ... Hubble Space Telescope has confirmed that the a, b, and h planets don't have hydrogen helium atmospheres, which means they aren't gassy ... 07:22: However, tidal forces could pose a serious problem to the inner planets. 07:42: ... is so much more mass in the TRAPPIST-1 star planet system than the Jupiter-Io-Europa system that, while the tides are about ... 08:06: Clearly, not all planets in the habitable zone are created equal. 08:14: Tidal locking, stellar activity, atmospheric composition, and volcanism can all turn an Earth-like planet uninhabitable. 08:23: But this finding tells us that Earth sized planets are probably common around M dwarf stars. 08:29: Remember also that a potentially habitable Earth-like planet was recently found orbiting the very nearby Proxima Centauri. 11:30: Slikrx asks the burning question, is the planet that was found in the Fomalhaut system in the Hobbitable zone? 11:38: No, I'm absolutely "shire" the planet is too far out for Hobbits. 02:22: It's also unlikely that enough material resources would have been available for so much planet forming so close to the star. 08:14: Tidal locking, stellar activity, atmospheric composition, and volcanism can all turn an Earth-like planet uninhabitable. 00:19: ... PLAYING] The TRAPPIST-1 planetary system was discovered by Dr. Michael Gillon and team and reported in the ... 06:27: This planetary system probably had a traumatic youth, which may not have been ideal for starting life. 00:19: ... PLAYING] The TRAPPIST-1 planetary system was discovered by Dr. Michael Gillon and team and reported in the ... 06:27: This planetary system probably had a traumatic youth, which may not have been ideal for starting life. 00:19: ... planets in the system was made in 2015, with the Transiting Planets and Planetesimals Small Telescope, TRAPPIST, at the La Silla Observatory in ... 00:10: A nearby red dwarf star was discovered to have not one, but seven Earth-like planets, and any of them may be capable of supporting life. 00:19: ... and team and reported in the journal, "Nature." The discovery of three planets in the system was made in 2015, with the Transiting Planets and ... 00:43: Follow up with the Spitzer Space Telescope has now revealed an additional four planets. 00:48: Both telescopes use the transit method, watching for the dimming of the central star as the planets pass in front of it. 00:56: Never before have we seen so many Earth-like planets in one place. 01:26: The seven planets huddle extremely close to this star-- all within one fifth of Mercury's orbit. 01:45: The planets live so close together that they all tug on each other gravitationally. 02:13: ... planets have now settled into stable orbital resonances with each other, and ... 02:30: ... different chemicals condense at different temperatures, planets' distance from the star during formation largely determines the planet's ... 02:46: Maybe the TRAPPIST-1 planets started out as mixtures of rock and ice. 02:50: However, three of them now occupy their star's habitable zone, where planet's surface temperature would be just right for liquid water. 03:23: But in that densely packed system, it covers three of the planets. 03:29: ... have done some climate modeling, which indicate that the three innermost planets may be more Venusian, so overheated due to a runaway greenhouse ... 03:48: ... and generated by tidal interactions with its star and the other planets could warm it to liquid water temperatures as ... 04:27: See, because the planets are so close to the star, they're probably tidally locked, like our moon. 04:47: These planets would be huge in each other's skies. 05:04: Partial eclipses of the central star by sister planets may be common, but there would be no full eclipses. 05:29: On the inner planets' sunny side, the star will provide about as much visible light as our sun. 05:35: Planets further out will receive less light, but the star's infrared intensity provides the heat needed for liquid water. 05:48: Being so close to the central star exposes the planets to stellar activity. 06:01: But within a tenth of an AU of TRAPPIST-1a, CMEs would be dangerous, and tidal locking would weaken the planet's protective magnetospheres. 06:12: The TRAPPIST-1a's winds may have eroded its planet's atmospheres, just as the sun did with Mars. 06:34: We don't yet know much about what those planet's atmospheres are like. 06:50: ... Hubble Space Telescope has confirmed that the a, b, and h planets don't have hydrogen helium atmospheres, which means they aren't gassy ... 07:22: However, tidal forces could pose a serious problem to the inner planets. 08:06: Clearly, not all planets in the habitable zone are created equal. 08:23: But this finding tells us that Earth sized planets are probably common around M dwarf stars. 06:12: The TRAPPIST-1a's winds may have eroded its planet's atmospheres, just as the sun did with Mars. 06:34: We don't yet know much about what those planet's atmospheres are like. 02:30: ... planets' distance from the star during formation largely determines the planet's chemical ... 06:50: ... Hubble Space Telescope has confirmed that the a, b, and h planets don't have hydrogen helium atmospheres, which means they aren't gassy planets ... 01:26: The seven planets huddle extremely close to this star-- all within one fifth of Mercury's orbit. 01:45: The planets live so close together that they all tug on each other gravitationally. 00:48: Both telescopes use the transit method, watching for the dimming of the central star as the planets pass in front of it. 06:01: But within a tenth of an AU of TRAPPIST-1a, CMEs would be dangerous, and tidal locking would weaken the planet's protective magnetospheres. 02:46: Maybe the TRAPPIST-1 planets started out as mixtures of rock and ice. 05:29: On the inner planets' sunny side, the star will provide about as much visible light as our sun. 02:50: However, three of them now occupy their star's habitable zone, where planet's surface temperature would be just right for liquid water.
	2017-02-22: The Eye of Sauron Reveals a Forming Solar System! 03:10: ... star in the center disperse this extra gas and dust, revealing whatever planets managed to form from the debris in that ... 03:20: The formation of planets itself is a fascinating process. 03:57: By the time it's at least 10% of the Earth's mass, it will have cleared its orbit of other planetesimals, and will have rounded out into a planet. 04:45: The leading idea is that newly formed planets carved out that ring with their gravity. 04:56: In Fomalhaut's case, it may be shepherd planets, guiding the dust into a well-defined tract. 05:22: So a planet passing along the inside of the dust ring overtakes each grain of dust and tugs them gently forward. 05:37: A planet passing along the outside of the dust ring pulls back on the dust. 05:47: Pushed outwards and inwards by the Shepherd planets, the dust ring boundaries sharpen between them. 05:54: But are there really planets there? 06:07: In fact, it is very possible that we've actually found the planet that carves out the inner edge of that ring. 06:26: It may actually be a much smaller planet, still wreathed in the dust of its formation. 06:37: Or even cooler, it may be a planet with a giant reflective ring system. 07:16: In fact, the entire planet may be a myth. 07:25: But the smart money is on it being a real planet. 07:34: ... far out, there shouldn't really have been enough resources to build a planet even at the lower end of Dagon's mass estimate, at around three earth ... 07:48: ... some critical point, it may have interacted with another massive planet in the system, sending that planet spiraling closer to Fomalhaut to ... 08:01: In fact, a similar model may explain the locations of our four gas giant planets. 09:25: We'll need to figure out if this planet is real and what causes its strange mismatch in visible and infrared light. 05:22: So a planet passing along the inside of the dust ring overtakes each grain of dust and tugs them gently forward. 05:37: A planet passing along the outside of the dust ring pulls back on the dust. 07:48: ... have interacted with another massive planet in the system, sending that planet spiraling closer to Fomalhaut to become a so-called hot Jupiter, while Dagon was ... 01:57: The whirlpool of debris left over after the star formed, and from which a planetary system may now be forming. 03:52: At this point, it's a planetesimal at about a kilometer in diameter. 03:57: By the time it's at least 10% of the Earth's mass, it will have cleared its orbit of other planetesimals, and will have rounded out into a planet. 03:52: At this point, it's a planetesimal at about a kilometer in diameter. 03:57: By the time it's at least 10% of the Earth's mass, it will have cleared its orbit of other planetesimals, and will have rounded out into a planet. 03:10: ... star in the center disperse this extra gas and dust, revealing whatever planets managed to form from the debris in that ... 03:20: The formation of planets itself is a fascinating process. 04:45: The leading idea is that newly formed planets carved out that ring with their gravity. 04:56: In Fomalhaut's case, it may be shepherd planets, guiding the dust into a well-defined tract. 05:47: Pushed outwards and inwards by the Shepherd planets, the dust ring boundaries sharpen between them. 05:54: But are there really planets there? 08:01: In fact, a similar model may explain the locations of our four gas giant planets. 04:45: The leading idea is that newly formed planets carved out that ring with their gravity. 04:56: In Fomalhaut's case, it may be shepherd planets, guiding the dust into a well-defined tract. 03:10: ... star in the center disperse this extra gas and dust, revealing whatever planets managed to form from the debris in that ...
	2017-02-15: Telescopes of Tomorrow 01:50: So planets form around young stars. 07:23: ... and unprecedented sharpness will actually allow to take photographs of planets in other solar systems and even to observe the spectra of the ... 01:50: So planets form around young stars. 07:23: ... and unprecedented sharpness will actually allow to take photographs of planets in other solar systems and even to observe the spectra of the ... 01:50: So planets form around young stars.
	2017-01-11: The EM Drive: Fact or Fantasy? 10:05: Harlan Kempf asks whether a radio interferometer could be built across multiple planets and what would be the effect on resolution.
	2017-01-04: How to See Black Holes + Kugelblitz Challenge Answer 02:59: It's a collaboration of currently nine and eventually 12 or more radio telescopes distributed across the planets.
	2016-12-21: Have They Seen Us? 00:31: ... advanced alien race monitoring our planet, even from the nearest neighboring star, would have seen nothing, radio ... 00:42: ... with wireless transmission, the radio brightness of this small planet would have bloomed into a continuous planet-wide cacophony of TV and ... 01:41: ... observations, that also means thousands of potentially habitable planets, lots of chances for hypothetical civilizations to have learned of our ... 09:02: These emission spikes may also shift back and forth in frequency due to Doppler shift, as the distant technologically advanced planet orbits its star. 01:41: ... observations, that also means thousands of potentially habitable planets, lots of chances for hypothetical civilizations to have learned of our ... 00:42: ... brightness of this small planet would have bloomed into a continuous planet-wide cacophony of TV and radio broadcasts, satellite relays, and radar ...
	2016-12-14: Escape The Kugelblitz Challenge 04:10: Scenario-- a super-advanced alien civilization decides to build a giant black hole that will engulf the planet Earth.
	2016-11-09: Did Dark Energy Just Disappear? 06:35: ... effect of regular energy, and that's mostly dark matter, but also stars, planets, gas, radiation, et ...
	2016-11-02: Quantum Vortices and Superconductivity + Drake Equation Challenge Answers 03:00: ... that tell us about the chance of such a civilization arising on any one planet? ... 03:24: ... -- that's this "A" number -- is equal to the number of habitable planets in that region -- that's "N (sub) ast" for "astrophysical factor" -- ... 04:33: There are a few different ways to get the number of habitable planets within 100 light years. 04:54: The Frank and Woodruff (Sullivan) paper estimates that around 1 in 5 stars has a terrestrial planet in the habitable zone. 05:05: So that means there are around 100 such planets orbiting stars like the sun within 100 light years. 05:11: ... civilization in the neighborhood, and that others could only form on planets similar to the Earth, we get that there's a 1 in 100 chance of this ... 05:52: If you allow that more star types can produce planets with life, then this number just gets smaller. 03:24: ... that a technological civilization will form on any given habitable planet -- that's "f (sub) bt" for "bio-technical factor." And it's that last ... 04:33: There are a few different ways to get the number of habitable planets within 100 light years. 05:05: So that means there are around 100 such planets orbiting stars like the sun within 100 light years. 05:11: ... civilization in the neighborhood, and that others could only form on planets similar to the Earth, we get that there's a 1 in 100 chance of this ... 05:52: If you allow that more star types can produce planets with life, then this number just gets smaller. 05:05: So that means there are around 100 such planets orbiting stars like the sun within 100 light years.
	2016-10-19: The First Humans on Mars 00:06: There's been a lot of talk lately about putting humans on Mars and even colonizing the red planet. 03:47: But with the advent of large-scale 3D printing, it's possible to build these structures on a planet's surface. 06:12: This has been proposed for artificial gravity on long-term space missions, but it's also possible on a planetary surface. 03:47: But with the advent of large-scale 3D printing, it's possible to build these structures on a planet's surface.
	2016-10-12: Black Holes from the Dawn of Time 08:14: If it passed anywhere near the planetary system, the gravitational tug would disrupt the planet's orbits. 08:57: ... a couple hundred kilometers per second, it'd punch straight through the planet, but certainly leave a narrow column a vaporized rock behind ... 09:25: In fact, they may pass through the planet frequently. 09:28: A billion-ton black hole has an event horizon around the size of a proton, so it would pass through the planet as though the Earth were made of air. 09:25: In fact, they may pass through the planet frequently. 08:14: If it passed anywhere near the planetary system, the gravitational tug would disrupt the planet's orbits.
	2016-10-05: Are We Alone? Galactic Civilization Challenge 00:33: ... include the rate of star formation in the Milky Way, the number of planets per star that could support life, the fraction of life bearing planets ... 02:14: We now have a very good idea of how many planets there are in the Milky Way that could potentially support life. 02:20: ... to estimate that our galaxy boasts something like 14 billion terrestrial planets in the Goldilocks zone of their parent ... 02:37: We call these habitable planets, although we have no idea how many are inhabited. 02:43: Around 11 billion of those are Earth-like planets around Sun-like stars. 03:25: ... in the history of the known universe, the chance for each habitable planet to produce such a civilization would need to be less than 2.5 by 10 to ... 03:57: ... there would need to be only a 1 in 60 billion chance for any suitable planet producing something like ... 04:38: ... is the only technological civilization to have arisen on any habitable planet within 100 light years, how low would that probability of technological ... 03:57: ... there would need to be only a 1 in 60 billion chance for any suitable planet producing something like ... 00:33: ... include the rate of star formation in the Milky Way, the number of planets per star that could support life, the fraction of life bearing planets ... 02:14: We now have a very good idea of how many planets there are in the Milky Way that could potentially support life. 02:20: ... to estimate that our galaxy boasts something like 14 billion terrestrial planets in the Goldilocks zone of their parent ... 02:37: We call these habitable planets, although we have no idea how many are inhabited. 02:43: Around 11 billion of those are Earth-like planets around Sun-like stars.
	2016-09-21: Quantum Entanglement and the Great Bohr-Einstein Debate 13:24: That said, other later invaders may have failed to find purchase on this planet once the first had come to dominate. 13:31: But if these artificial panspermianic seeds are common, then we should expect to find them in space and on other planetary surfaces.
	2016-09-14: Self-Replicating Robots and Galactic Domination 07:28: There are, at a minimum, tens of billions of terrestrial planets with liquid water in our galaxy. 07:36: ... least tens, but perhaps hundreds of millions of years earlier on our own planet. ... 07:46: ... life is even remotely common-- say it evolves in one in 1,000 habitable planets-- and another one in 1,000 of these evolve technological species, that ... 11:01: Well, a full Dyson swarm interior to Earth's orbit would, indeed, block sunlight and freeze our planet. 03:50: ... that will be powered by a solar sail-fed ion drive that could harvest planetary resources to build more of itself-- a self-replicating spacecraft, a Von ... 05:55: ... it launches probes to actually explore the planetary system, and stream the data back home, or terraform the system, or build ... 03:50: ... that will be powered by a solar sail-fed ion drive that could harvest planetary resources to build more of itself-- a self-replicating spacecraft, a Von ... 05:55: ... it launches probes to actually explore the planetary system, and stream the data back home, or terraform the system, or build ... 03:50: ... that will be powered by a solar sail-fed ion drive that could harvest planetary resources to build more of itself-- a self-replicating spacecraft, a Von Neumann ... 07:28: There are, at a minimum, tens of billions of terrestrial planets with liquid water in our galaxy. 07:46: ... life is even remotely common-- say it evolves in one in 1,000 habitable planets-- and another one in 1,000 of these evolve technological species, that ...
	2016-08-24: Should We Build a Dyson Sphere? 01:55: ... much more than there is non-hydrogen or helium matter in all of the planets in the solar ... 03:26: We'd have to disassemble entire planets for the raw materials alone. 03:39: The idea is to cannibalize the planet Mercury. 03:45: Mercury is ideal, because it has a gigantic solid iron core, comprising over 40% of the planet's mass. 06:06: Once complete, the Dyson swarm would harvest a good fraction of the sun's energy, so trillions of times the current energy output of the planet. 06:47: Also, we need a mega structure to harvest it, with a raw material requirement close to that of all the terrestrial planets in the solar system. 03:39: The idea is to cannibalize the planet Mercury. 01:38: The plausibility of a solid sphere the size of a planetary orbit is not really in question. 01:55: ... much more than there is non-hydrogen or helium matter in all of the planets in the solar ... 03:26: We'd have to disassemble entire planets for the raw materials alone. 03:45: Mercury is ideal, because it has a gigantic solid iron core, comprising over 40% of the planet's mass. 06:47: Also, we need a mega structure to harvest it, with a raw material requirement close to that of all the terrestrial planets in the solar system. 03:45: Mercury is ideal, because it has a gigantic solid iron core, comprising over 40% of the planet's mass.
	2016-08-10: How the Quantum Eraser Rewrites the Past 11:37: These may have masses similar to planets rather than stars, if they exist. 11:10: ... the solar system, even if nowhere near the Earth, would probably disrupt planetary orbits and either rearrange or scatter our planetary ... 11:37: These may have masses similar to planets rather than stars, if they exist.
	2016-08-03: Can We Survive the Destruction of the Earth? ft. Neal Stephenson 08:40: For example, a huge amount of smoggy nitrogen oxide would blanket the planet, causing a supernova winter. 08:14: But there is one threat that no settlement on any planetary surface or space hotel in the solar system can protect us from-- that's an exploding star. 09:44: No planetary surface or space ark in the solar system would be safe from a supernova or a gamma ray burst. 08:14: But there is one threat that no settlement on any planetary surface or space hotel in the solar system can protect us from-- that's an exploding star. 09:44: No planetary surface or space ark in the solar system would be safe from a supernova or a gamma ray burst. 08:14: But there is one threat that no settlement on any planetary surface or space hotel in the solar system can protect us from-- that's an exploding star. 09:44: No planetary surface or space ark in the solar system would be safe from a supernova or a gamma ray burst.
	2016-07-27: The Quantum Experiment that Broke Reality 12:57: These integer ratios maximize the amount of time that the planets spend in closest proximity.
	2016-07-06: Juno to Reveal Jupiter's Violent Past 00:02: Two days ago on the 4th of July, 2016, the Juno spacecraft entered orbit around the planet, Jupiter after a five-year journey from Earth. 00:14: ... Jupiter is the second most important planet in the universe, at least from our point of view, and it holds the ... 00:37: It may only have 1,000th of the sun's mass, but it weighs more than all the other planets combined, two and 1/2 times more. 00:45: Jupiter's enormous gravity influences the orbit of all the planets in the solar system. 01:04: But first, let's talk about the planet itself. 01:08: Jupiter was probably the first planet to start forming in our system. 01:22: ... the 300-ish Earth masses of hydrogen and helium that make up most of the planet ... 01:36: That solid core now comprises, at most, 15% of the planet's mass. 03:58: At first, there was the gassy, dusty protoplanetary disk, and then a mess of asteroids and planetesimals left over from the formation of the planets. 04:12: A planet can lose angular momentum to the debris, causing its orbit to shrink. 04:17: The planet migrates inwards in a similar way to a satellite falling to the Earth due to dragging against the upper atmosphere. 04:25: The planet can even migrate outwards, stealing angular momentum from the debris. 04:29: Astrophysicists have run many computer simulations to find formation scenarios that lead to the configuration of planets that we see today. 04:39: There's more than one possibility, because we don't know exactly how the formation of planets started. 04:45: ... disk before settling into its current orbit or driving other planets to do the ... 05:46: ... changed the way the planets interacted with the surrounding disk, and, in fact, they would then have ... 06:15: ... of forming Venus and Earth should also have formed another massive planet, at least half of Earth's mass in Mars's ... 06:31: ... clearing it of a lot of the material it needed to build another large planet in Mars's ... 06:43: Another clue is that other real exoplanetary systems tend to have super Earths, rocky planets several times the mass of our own planet. 06:56: ... early rampage into the inner solar system would have sent such planets spiraling into the sun, leaving only a limited amount of material to ... 07:44: The solar system at this point had all its planets-- eight, maybe nine of them-- but also a huge amount of left over junk. 09:01: Oh, and it may also have nearly ejected Planet Nine, which we may have recently found lurking far, far out beyond the Kuiper Belt. 09:13: ... an early obliteration of Earth's surface, and, perhaps, a missing ninth planet. ... 09:45: Answer that, and we can nail down these simulations to truly understand our planet's origin. 13:07: As a physicist, I usually approximate everything as a sphere, including planets, so approximating a tortoise as a turtle is actually pretty good. 00:02: Two days ago on the 4th of July, 2016, the Juno spacecraft entered orbit around the planet, Jupiter after a five-year journey from Earth. 04:17: The planet migrates inwards in a similar way to a satellite falling to the Earth due to dragging against the upper atmosphere. 01:22: ... the 300-ish Earth masses of hydrogen and helium that make up most of the planet today. ... 00:50: In fact, its effect during the first billion years of the solar system's formation defines the positions of all planetary orbits. 05:20: With these first millions of years of planetary life, it was still embedded in the thick protoplanetary disk. 00:50: In fact, its effect during the first billion years of the solar system's formation defines the positions of all planetary orbits. 05:20: With these first millions of years of planetary life, it was still embedded in the thick protoplanetary disk. 00:50: In fact, its effect during the first billion years of the solar system's formation defines the positions of all planetary orbits. 03:58: At first, there was the gassy, dusty protoplanetary disk, and then a mess of asteroids and planetesimals left over from the formation of the planets. 08:13: Beyond Neptune was a vast sea of planetesimals, many thousands of tiny, icy worlds. 08:42: As the three outer gas giants plowed through the great field of planetesimals, they scattered this material through the solar system. 03:58: At first, there was the gassy, dusty protoplanetary disk, and then a mess of asteroids and planetesimals left over from the formation of the planets. 08:13: Beyond Neptune was a vast sea of planetesimals, many thousands of tiny, icy worlds. 08:42: As the three outer gas giants plowed through the great field of planetesimals, they scattered this material through the solar system. 03:58: At first, there was the gassy, dusty protoplanetary disk, and then a mess of asteroids and planetesimals left over from the formation of the planets. 08:13: Beyond Neptune was a vast sea of planetesimals, many thousands of tiny, icy worlds. 08:42: As the three outer gas giants plowed through the great field of planetesimals, they scattered this material through the solar system. 03:58: At first, there was the gassy, dusty protoplanetary disk, and then a mess of asteroids and planetesimals left over from the formation of the planets. 08:13: Beyond Neptune was a vast sea of planetesimals, many thousands of tiny, icy worlds. 00:37: It may only have 1,000th of the sun's mass, but it weighs more than all the other planets combined, two and 1/2 times more. 00:45: Jupiter's enormous gravity influences the orbit of all the planets in the solar system. 01:36: That solid core now comprises, at most, 15% of the planet's mass. 03:58: At first, there was the gassy, dusty protoplanetary disk, and then a mess of asteroids and planetesimals left over from the formation of the planets. 04:29: Astrophysicists have run many computer simulations to find formation scenarios that lead to the configuration of planets that we see today. 04:39: There's more than one possibility, because we don't know exactly how the formation of planets started. 04:45: ... disk before settling into its current orbit or driving other planets to do the ... 05:46: ... changed the way the planets interacted with the surrounding disk, and, in fact, they would then have ... 06:43: Another clue is that other real exoplanetary systems tend to have super Earths, rocky planets several times the mass of our own planet. 06:56: ... early rampage into the inner solar system would have sent such planets spiraling into the sun, leaving only a limited amount of material to ... 07:44: The solar system at this point had all its planets-- eight, maybe nine of them-- but also a huge amount of left over junk. 09:45: Answer that, and we can nail down these simulations to truly understand our planet's origin. 13:07: As a physicist, I usually approximate everything as a sphere, including planets, so approximating a tortoise as a turtle is actually pretty good. 00:37: It may only have 1,000th of the sun's mass, but it weighs more than all the other planets combined, two and 1/2 times more. 05:46: ... changed the way the planets interacted with the surrounding disk, and, in fact, they would then have slowly ... 01:36: That solid core now comprises, at most, 15% of the planet's mass. 09:45: Answer that, and we can nail down these simulations to truly understand our planet's origin. 06:56: ... early rampage into the inner solar system would have sent such planets spiraling into the sun, leaving only a limited amount of material to then build ... 04:39: There's more than one possibility, because we don't know exactly how the formation of planets started.
	2016-05-25: Is an Ice Age Coming? 01:38: You might forgive us for imagining that these relatively summery millennia are normal for this planet. 04:56: We can reconstruct our planet's climate history by digging holes. 06:26: Every time Earth's orbit becomes more circular, the planet warms and the glaciers go away. 04:56: We can reconstruct our planet's climate history by digging holes.
	2016-05-04: Will Starshot's Insterstellar Journey Succeed? 04:51: So less vast alien mega structure slash planet destroyer and more Bond super-villain laser. 05:51: ... launch with camera tech capable of resolving continents and oceans on planets orbiting Alpha Cen, assuming they have ... 06:05: Some type of color spectral sensitivity may even point to life signatures on these planets. 04:51: So less vast alien mega structure slash planet destroyer and more Bond super-villain laser. 05:51: ... launch with camera tech capable of resolving continents and oceans on planets orbiting Alpha Cen, assuming they have ... 06:05: Some type of color spectral sensitivity may even point to life signatures on these planets. 05:51: ... launch with camera tech capable of resolving continents and oceans on planets orbiting Alpha Cen, assuming they have ...
	2016-04-13: Will the Universe Expand Forever? 11:23: ... and then blown into space as the outer layers are blown away into a planetary ...
	2016-04-06: We Are Star Stuff 01:18: ... complexity is what makes it possible for a universe to have things like planets, life, and minds to try to comprehend it all in the first ... 07:11: And collapse it does, taking about a tenth of a second to collapse from around the size of planet Earth to the size of a city. 07:45: And with them, planetary systems and life. 01:18: ... complexity is what makes it possible for a universe to have things like planets, life, and minds to try to comprehend it all in the first ...
	2016-03-16: Why is the Earth Round and the Milky Way Flat? 00:23: It loves building spheres like stars, planets, and moons, and disks like spiral galaxies, solar systems, and some crazy stuff like quasars. 01:43: ... terms of shape, things like planets and stars have spherical symmetry, meaning you can rotate them in three ... 02:53: And this type of dimensional egalitarianism is also shared by another effect, ultimately leading to the ball shapes of stars, planets, and moons. 03:05: Before we talk about what that other effect is, let's talk about planets. 04:15: We can sort of think of the planet as a huge number of these block towers, each one in perfect equilibrium in their up-down forces. 05:28: But that is not the case with our flattened planet. 06:12: This is all assuming a planet made of separate blocks. 06:15: But what about a planet made of completely solid rock? 06:39: So a relatively solid, rocky planet will fracture and reshape itself into a sphere as long as its own gravitational field is strong enough. 08:29: These things are even more massive than single planets or stars. 09:37: ... disks of stuff will clump off and form the star in the center and the planets further out, but the disk structure remains long after all the gas is ... 00:23: It loves building spheres like stars, planets, and moons, and disks like spiral galaxies, solar systems, and some crazy stuff like quasars. 01:43: ... terms of shape, things like planets and stars have spherical symmetry, meaning you can rotate them in three ... 02:53: And this type of dimensional egalitarianism is also shared by another effect, ultimately leading to the ball shapes of stars, planets, and moons. 03:05: Before we talk about what that other effect is, let's talk about planets. 08:29: These things are even more massive than single planets or stars. 09:37: ... disks of stuff will clump off and form the star in the center and the planets further out, but the disk structure remains long after all the gas is ...
	2016-02-17: Planet X Discovered?? + Challenge Winners! 00:00: [MUSIC PLAYING] Have we finally discovered Planet X? 00:16: This is a potential near-Nepture sized planet. 00:22: [MUSIC PLAYING] Caltech planet hunters Mike Brown and Konstantin Batygin have been the trail of something big out there for some time. 00:35: ... as accomplice to the murder of Pluto, which was demoted to dwarf planet partly due to Brown's discovery of Eris, a distant planetary body that's ... 00:55: You see, Brown also found Sedna, a minor planet, whose elongated orbit takes it out way beyond the Kuiper Belt. 01:10: ... was actually competing planet hunters, Chad Trujillo and Scott Sheppard, who first noticed that ... 01:25: They suggested the possibility of a large planet out there, dragging on these objects with its gravitational pull. 01:31: ... and found a single compelling solution, a very, very distant giant planet, with a mass well over 10 times that of the Earth, and a stretched out ... 02:34: Now, people have claimed the discovery of Planet X before. 02:51: But did we really find Planet X this time? 00:22: [MUSIC PLAYING] Caltech planet hunters Mike Brown and Konstantin Batygin have been the trail of something big out there for some time. 01:10: ... was actually competing planet hunters, Chad Trujillo and Scott Sheppard, who first noticed that several Kuiper ... 00:22: [MUSIC PLAYING] Caltech planet hunters Mike Brown and Konstantin Batygin have been the trail of something big out there for some time. 00:35: ... as accomplice to the murder of Pluto, which was demoted to dwarf planet partly due to Brown's discovery of Eris, a distant planetary body that's larger ...
	2016-02-11: LIGO's First Detection of Gravitational Waves! 07:18: ... of Venus versus Mars by looking at some nice ways to die on both planets. ...
	2016-02-03: Will Mars or Venus Kill You First? 00:00: [MUSIC PLAYING] If we want to get to the stars, we don't have to learn how to live on other planets. 00:19: The surface of planet Earth is an unusual place. 00:39: However, in order to do so, we first have to learn to live on other planets. 01:09: However, there are some real problems with this planet. 08:03: ... actually induces something of a protective magnetic sheath around the planet, not as good as Earth, but not as bad as ... 08:54: ... all of that high-energy craziness, then somehow found its way to planet Earth without having spent a lot of time traveling close to the speed of ... 00:19: The surface of planet Earth is an unusual place. 08:54: ... all of that high-energy craziness, then somehow found its way to planet Earth without having spent a lot of time traveling close to the speed of ... 00:00: [MUSIC PLAYING] If we want to get to the stars, we don't have to learn how to live on other planets. 00:39: However, in order to do so, we first have to learn to live on other planets.
	2015-12-09: How to Build a Black Hole 12:35: ... if we want a ring system like Sam's, that has the same ratio of planet mass to ring mass-- of about 1 to 50 billion, then we'd need an object ...
	2015-11-18: 5 Ways to Stop a Killer Asteroid 00:03: It's a scientific fact that the planet Earth will be hit by cataclysmic asteroids in the future. 00:11: ... Space is swarming with lots of really fast moving rocks, like the planet Earth, but also like that 19-meter-wide wide chunk, that blazed across ... 02:21: Much larger than this and the planet is showered in molten rock. 04:09: And speaking of Armageddon, what do we do if we spot an incoming city killer, or for that matter, a planet killer that we somehow missed? 05:17: Now unfortunately, this doesn't work for planet killers, which are at least a million times more massive. 05:38: But for a planet killer, you're going to need a few 50 megaton Tsar bombs. 08:12: Science has given us such incredible power-- among other things, to serve as custodians of the planet Earth. 10:10: Sam Shields asks whether Panspermia is suggesting that life only arose on one planet in the Milky Way before being spread everywhere. 10:30: ... to be very unlikely, and yet have life arise quickly on another planet. ... 00:03: It's a scientific fact that the planet Earth will be hit by cataclysmic asteroids in the future. 00:11: ... Space is swarming with lots of really fast moving rocks, like the planet Earth, but also like that 19-meter-wide wide chunk, that blazed across the sky ... 08:12: Science has given us such incredible power-- among other things, to serve as custodians of the planet Earth. 04:09: And speaking of Armageddon, what do we do if we spot an incoming city killer, or for that matter, a planet killer that we somehow missed? 05:38: But for a planet killer, you're going to need a few 50 megaton Tsar bombs. 05:17: Now unfortunately, this doesn't work for planet killers, which are at least a million times more massive. 08:05: We are a species capable of defending our world from a planet-killing meteor strike.
	2015-11-11: Challenge: Can you save Earth from a Killer Asteroid? 00:14: We're going to use some rocket science to save the planet. 02:39: Good luck saving planet Earth.
	2015-11-05: Why Haven't We Found Alien Life? 00:26: ... has told us there are a couple of hundred billion nice, watery planets in the Milky Way and probably billions of them are Earth-sized planets ... 00:43: ... catastrophe, accidentally making a black hole that swallows the planet, et ... 02:01: ... an observer will always observe a universe that can make observers or a planet that ... 04:20: Basically, Earth was once a giant slimeball planet. 06:10: Look, there's no question that lots of rock gets ejected into space after meteor impacts and can move between planets. 06:42: ... even millions, of years later a single bug winds up on a brand new planet and boom, instant ... 07:27: However, both suggest that the galaxy should be teeming with slimeball planets filled with life. 07:38: These planets will have atmospheres driven by biotic processes. 07:52: Properly fund NASA and its terrestrial planet finder and we could find extraterrestrial life within 20 years. 09:19: ... life is common, then of the billions of Earth-like planets in the galaxy, only a tiny fraction needed to have a small head start on ... 09:33: ... all of the sun-like stars and Earth-like planets that will ever form over the full past and future history of star ... 07:52: Properly fund NASA and its terrestrial planet finder and we could find extraterrestrial life within 20 years. 00:26: ... has told us there are a couple of hundred billion nice, watery planets in the Milky Way and probably billions of them are Earth-sized planets ... 06:10: Look, there's no question that lots of rock gets ejected into space after meteor impacts and can move between planets. 07:27: However, both suggest that the galaxy should be teeming with slimeball planets filled with life. 07:38: These planets will have atmospheres driven by biotic processes. 09:19: ... life is common, then of the billions of Earth-like planets in the galaxy, only a tiny fraction needed to have a small head start on ... 09:33: ... all of the sun-like stars and Earth-like planets that will ever form over the full past and future history of star ... 07:27: However, both suggest that the galaxy should be teeming with slimeball planets filled with life.
	2015-10-15: 5 REAL Possibilities for Interstellar Travel 00:21: Is our galaxy littered with the remains of single planet civilizations as Elon Musk has asked?
	2015-09-30: What Happens At The Edge Of The Universe? 08:25: Shadowmax889 asks why stars and planets aren't filled with dark matter? 08:03: For example, the predictions GR makes for planetary orbits can give us a mass for the Sun. 08:25: Shadowmax889 asks why stars and planets aren't filled with dark matter?
	2015-08-27: Watch THIS! (New Host + Challenge Winners) 00:03: Which of two particles, one orbiting around the outside of a planet and one going straight through the middle, reaches the other side first? 00:15: ... for the gravitational force on the particle that's falling through the planet when it's a distance r from the center of the ... 00:50: ... expression for the period of oscillation of a particle falling through a planet. ... 01:09: ... out an expression for the orbital period of a particle moving under the planet's gravity in a circular orbit right at the ... 01:26: This is kind of a coincidence of the specific situation of a uniformly dense planet and Newtonian mechanics. 01:46: You have to do the algebra in this case, because this is very specific to the situation of a uniformly dense planet. 03:19: ... assuming the collision with Andromeda doesn't disrupt our planetary system, it'll be a white dwarf remnant, and after the sun ejects its ... 01:09: ... out an expression for the orbital period of a particle moving under the planet's gravity in a circular orbit right at the ...
	2015-08-19: Do Events Inside Black Holes Happen? 07:03: ... Newtonian gravity, a projectile on the surface of a planet or a star needs a minimum speed called the escape velocity in order to ... 07:15: If a planet's radius equals the Schwarzschild radius of the equivalent-mass black hole, it turns out that the escape velocity is the speed of light. 06:29: For example, that is an allowed planetary orbit in that region. 07:03: ... in order to get really far and not turn back as it's pulled by the planet's ... 07:15: If a planet's radius equals the Schwarzschild radius of the equivalent-mass black hole, it turns out that the escape velocity is the speed of light. 07:03: ... in order to get really far and not turn back as it's pulled by the planet's gravity. ... 07:15: If a planet's radius equals the Schwarzschild radius of the equivalent-mass black hole, it turns out that the escape velocity is the speed of light.
	2015-08-12: Challenge: Which Particle Wins This Race? 00:40: For simplicity, I'm going to refer to this sphere as a planet, but it could be any other massive body. 00:46: Suppose that a particle is orbiting the planet right at the surface. 00:59: ... orbital speed of this particle in terms of the mass and radius of the planet, or in terms of the density and radius of the ... 01:12: ... mind, and now imagine a second particle that we release from rest at the planet's surface and that we allow to fall through the center of the planet to ... 01:21: You can imagine doing this with a super thin evacuated tunnel along a diameter of the planet. 01:26: But I think it's easier to pretend that the planet is a uniformly dense fluid, and that this particle can pass through that fluid without friction. 01:44: Remember, they're both on the planet's surface. 01:47: Now each of them will eventually arrive at the antipodal point on the planet. 01:56: When the second particle is inside the planet, how do you calculate the gravitational force on it? 02:15: ... any given location inside the planet, the particle will feel only the gravitational force from whatever mass ... 02:26: ... on the particle when it's a distance little r from the center of the planet. ... 02:40: ... for the gravitational force on the second particle when it's inside the planet should algebraically resemble a familiar non-gravitational force that ... 03:04: The answer to which particle wins the race comes out the same regardless of the mass and radius of the planet, or of the masses of the two particles. 04:13: ... depart simultaneously as measured by the clock at one end of the planet, which one arrives first according to the clock at the other end of the ... 04:44: ... out who arrives first according to the clock on the other side of the planet. ... 01:12: ... mind, and now imagine a second particle that we release from rest at the planet's surface and that we allow to fall through the center of the planet to ... 01:44: Remember, they're both on the planet's surface. 01:12: ... mind, and now imagine a second particle that we release from rest at the planet's surface and that we allow to fall through the center of the planet to the other ... 01:44: Remember, they're both on the planet's surface.
	2015-08-05: What Physics Teachers Get Wrong About Tides! 05:33: ... pushes on all the chunks of water added up over half the surface of the planet can produce a pretty decent increase in water ... 05:59: ... the moon is turning the entire ocean into a planet sized hydraulic pump and the ocean is bulging along the Earth/Moon line ... 06:21: See, unlike the oceans, a single lake is not a contiguous, planet sized body of water. 07:03: ... amount, making the change in water level relative to the surface of the planet even less ... 08:47: ... Porscher911, one of our viewers, once asked how Miller's planet in the movie "Interstellar" could've had such a huge waves without the ... 08:59: ... nevertheless, when it comes to liquid on a planet, the squeezing aspect of tidal forces will almost always be more ... 05:59: ... the moon is turning the entire ocean into a planet sized hydraulic pump and the ocean is bulging along the Earth/Moon line in the ... 06:21: See, unlike the oceans, a single lake is not a contiguous, planet sized body of water. 05:59: ... the moon is turning the entire ocean into a planet sized hydraulic pump and the ocean is bulging along the Earth/Moon line in the same way ...
	2015-07-29: General Relativity & Curved Spacetime Explained! 07:50: ... those geodesics into 3D spatial and temporal terms, what you find is planetary orbits or spatially straight, radially inward trajectories along which ...
	2015-06-24: The Calendar, Australia & White Christmas 00:16: ... by approximately 23 and 1/2 degrees, so that different parts of the planet will receive more direct sunlight at different times of ... 05:32: And we end up keeping the current calendar, but just detach it from our home planet. 06:04: ... about different possible ways to signal aliens, including maybe putting planet-sized geometric objects in orbit around the ...
	2015-06-17: How to Signal Aliens 03:28: ... a few years, looking for the tiny dips in starlight that occur when a planet transits in front of its host star along our line of ... 03:45: Now, if Kerbals are doing astronomy-- and that's our target audience-- they're probably also looking for planets. 04:07: What if, instead of a planet, the object that's transiting in front of its star looks like this? 04:14: ... of objects like these could be distinguished from those of round planets. ... 04:30: Now, these objects wouldn't need to be the same mass as a planet. 03:28: ... a few years, looking for the tiny dips in starlight that occur when a planet transits in front of its host star along our line of ... 03:45: Now, if Kerbals are doing astronomy-- and that's our target audience-- they're probably also looking for planets. 04:14: ... of objects like these could be distinguished from those of round planets. ...
	2015-06-03: Is Gravity An Illusion? 05:05: ... from having that car stationary on the surface of some other planet with slightly bigger gravity than Earth and tilted upward by about 30 ... 05:18: ... and his kids know, they're completely at rest, tilted upward on another planet in a perfectly inertial ... 10:25: Primarily, JWST is an infrared telescope that will see exoplanets because, contrary to Earthenfist's comment, planets do glow, in the infrared. 10:32: ... super-Earths maybe that are very close to red dwarfs because only those planets will heat up enough to be bright in the ... 10:46: ... JWST could see dimmer planets if it had enough continuous observation, but that probably won't happen ... 11:08: ... of how proximity to different kinds of stars affects the atmospheres of planets, and so forth-- the prospect for life, ... 11:16: We can't reposition the planets here, so other star systems are the laboratories for these kinds of investigations. 11:08: ... want better understandings of how planetary systems form, of how proximity to different kinds of stars affects the ... 10:25: Primarily, JWST is an infrared telescope that will see exoplanets because, contrary to Earthenfist's comment, planets do glow, in the infrared. 10:32: ... super-Earths maybe that are very close to red dwarfs because only those planets will heat up enough to be bright in the ... 10:46: ... JWST could see dimmer planets if it had enough continuous observation, but that probably won't happen ... 11:08: ... of how proximity to different kinds of stars affects the atmospheres of planets, and so forth-- the prospect for life, ... 11:16: We can't reposition the planets here, so other star systems are the laboratories for these kinds of investigations.
	2015-05-27: Habitable Exoplanets Debunked! 00:08: But how much like Earth are these planets really? 00:25: ... these stories are accompanied by pictures that look a lot like M-class planets from Star Trek, with a solid surface, liquid water, and a surface ... 00:41: In fact, we have no idea whether any of these planets has water or oxygen, let alone whether you could just walk out of a ship and hang out there. 01:04: ... which the energy from starlight would produce the right temperature on a planet's surface for water to remain liquid, provided the planet actually has a ... 01:39: A planet with a super-thick atmosphere, for example, could have surface water in a larger orbit than you'd ordinarily expect. 01:50: Those estimates you hear of an average of one habitable planet per star in the Milky Way are really just statements about this starting point. 02:18: In April 2014, this planet got a lot of press as the first confirmed Earth-sized exoplanet in the habitable zone of its host star. 02:32: It shows the microscopic dip in starlight measured by the Kepler Telescope when the planet moved in front of its star. 02:39: ... and for how long, astronomers were able to infer the radius of the planet and some features of its orbit, like its approximate distance from that ... 02:57: So Basically, it's a planet like Krypton. 03:54: ... analyze a planet's atmosphere, you need to isolate the planet's light from that of its star ... 04:12: ... you combine that information with the planet's mass, radius, and distance from its star, you can use models to get a ... 04:20: So how do you isolate a planet's light? 04:23: ... you can directly image the planet, improving the contrast by blocking out the star's light, kind of like ... 04:32: But this only works for planet that are in very large orbits outside the habitable zone, because closer in, the contrast is still too low. 04:39: The planet just gets washed out by the star's light. 04:47: You take a spectrum of the star when the planet is in front of it. 04:50: This will be the combined spectrum of the planet and star. 04:57: Subtract the two, and you get the spectrum of just the planet. 05:01: ... unfortunately, this method only works for planets that are really close to their stars, because only planets that are ... 05:13: To be in the habitable zone, a planet has to be small enough to be rocky like Earth instead of gaseous like Jupiter. 05:34: ... was a proposal for a terrestrial planet finder, or TPF, a space telescope that could have analyzed the ... 04:23: ... you can directly image the planet, improving the contrast by blocking out the star's light, kind of like putting your ... 02:32: It shows the microscopic dip in starlight measured by the Kepler Telescope when the planet moved in front of its star. 04:44: The second method takes advantage of what are called planetary transits. 00:08: But how much like Earth are these planets really? 00:25: ... these stories are accompanied by pictures that look a lot like M-class planets from Star Trek, with a solid surface, liquid water, and a surface ... 00:41: In fact, we have no idea whether any of these planets has water or oxygen, let alone whether you could just walk out of a ship and hang out there. 01:04: ... which the energy from starlight would produce the right temperature on a planet's surface for water to remain liquid, provided the planet actually has a ... 03:54: ... analyze a planet's atmosphere, you need to isolate the planet's light from that of its star ... 04:12: ... you combine that information with the planet's mass, radius, and distance from its star, you can use models to get a ... 04:20: So how do you isolate a planet's light? 05:01: ... unfortunately, this method only works for planets that are really close to their stars, because only planets that are ... 05:34: ... space telescope that could have analyzed the atmospheres of Earth-sized planets in Earth-like orbits around Sun-like like ... 03:54: ... analyze a planet's atmosphere, you need to isolate the planet's light from that of its star and see how ... 04:20: So how do you isolate a planet's light? 04:12: ... you combine that information with the planet's mass, radius, and distance from its star, you can use models to get a rough ... 01:04: ... which the energy from starlight would produce the right temperature on a planet's surface for water to remain liquid, provided the planet actually has a surface ...
	2015-05-20: The Real Meaning of E=mc² 08:51: Would the total mass of the planet increase, and if so by how much?
	2015-05-06: Should the First Mars Mission Be All Women? 03:45: There's still another argument for preferring women to men on longer space missions-- namely that it costs less to send them to other planets.
	2015-04-29: What's the Most Realistic Artificial Gravity in Sci-Fi? 01:06: You'd need either enormous amounts of mass, so much that you'd basically have a planet and not a starship. 06:43: ... Grazier, a planetary scientists formerly at NASA, who was also the science adviser for ...
	2015-04-08: Could You Fart Your Way to the Moon? 07:44: ... seem to need the moon to orbit around the planet at the same rate that the planet spins on its axis, which I agree is not ...
	2015-04-01: Is the Moon in Majora’s Mask a Black Hole? 00:00: [MUSIC PLAYING] In "The Legend of Zelda: Majora's Mask," Link needs to save Termina from an impending collision with that planet's malevolent moon. 00:25: Link arrives in Termina, a province on a planet whose moon is on a three-day collision course with the surface. 00:31: Now, the planet doesn't seem to have a name, so I'll just refer to the whole place as Termina. 02:00: The same would be true on Termina, no matter what non-absurd radius and mass we assign to that planet. 02:15: The key evidence appears in the scenes just before the moon hits, when loose rocks start flying upward off the surface of the planet. 02:23: ... on the rocks due to the moon exceeds the gravitational pull from the planet itself, but that's not ... 02:30: What has to beat the planet's gravity, in this case, to make the rocks levitate is something called the moon's tidal force. 02:41: But the planet is also being pulled towards the moon, chasing after those rocks. 02:45: ... accelerate towards the moon slightly more quickly than the rest of the planet ... 02:52: Now, on its own, this differential acceleration tends to separate rocks from the planet, even on the side of the planet opposite the moon. 03:00: ... on the far side of the planet accelerate toward the moon even less quickly than the center of the ... 03:09: ... then, the moon's tidal force manifests itself as an outward push off the planet's surface, at least along the planet-moon line, kind of like ... 03:18: Ordinarily, though, that outward push is tiny, so tiny that a planet's own gravity is more than enough to hold things in place. 03:50: And I put some lower limits on the radius of the planet, based on the fact that we don't see its horizon curving in the distance. 04:00: ... as dense as Earth's moon, its tidal force when hovering just above the planet's surface would be 200,000 times smaller than the moon's current measly ... 04:40: After all, the planet also exerts a tidal force on the moon, which would rip Earth's moon apart if it got too close to us. 03:00: ... on the far side of the planet accelerate toward the moon even less quickly than the center of the planet does, so ... 03:50: And I put some lower limits on the radius of the planet, based on the fact that we don't see its horizon curving in the distance. 00:31: Now, the planet doesn't seem to have a name, so I'll just refer to the whole place as Termina. 02:52: Now, on its own, this differential acceleration tends to separate rocks from the planet, even on the side of the planet opposite the moon. 03:09: ... itself as an outward push off the planet's surface, at least along the planet-moon line, kind of like ... 00:00: [MUSIC PLAYING] In "The Legend of Zelda: Majora's Mask," Link needs to save Termina from an impending collision with that planet's malevolent moon. 02:30: What has to beat the planet's gravity, in this case, to make the rocks levitate is something called the moon's tidal force. 03:00: ... of the planet does, so they would also have a tendency to leave the planet's ... 03:09: ... then, the moon's tidal force manifests itself as an outward push off the planet's surface, at least along the planet-moon line, kind of like ... 03:18: Ordinarily, though, that outward push is tiny, so tiny that a planet's own gravity is more than enough to hold things in place. 04:00: ... as dense as Earth's moon, its tidal force when hovering just above the planet's surface would be 200,000 times smaller than the moon's current measly ... 02:30: What has to beat the planet's gravity, in this case, to make the rocks levitate is something called the moon's tidal force. 00:00: [MUSIC PLAYING] In "The Legend of Zelda: Majora's Mask," Link needs to save Termina from an impending collision with that planet's malevolent moon. 03:00: ... of the planet does, so they would also have a tendency to leave the planet's surface. ... 03:09: ... then, the moon's tidal force manifests itself as an outward push off the planet's surface, at least along the planet-moon line, kind of like ... 04:00: ... as dense as Earth's moon, its tidal force when hovering just above the planet's surface would be 200,000 times smaller than the moon's current measly tidal ...
	2015-03-25: Cosmic Microwave Background Explained 03:06: At this temperature, it's too hot for electrons and protons to even coalesce into atoms, let alone stars, planets or galaxies.
	2015-03-18: Can A Starfox Barrel Roll Work In Space? 01:56: ... any rigid spinning object, like a planet, will continue to spin at exactly the same rate, along the same axis, ... 02:30: Now, on a planet, the clockwise and subsequent counter-clockwise torques required to do this are provided by the atmosphere. 07:00: ... episode of "Space Time." Last week, we talked about what might destroy planet Earth, and you guys have a lot to ... 07:41: ... Grey Goo-- the possibility that advanced nanobots might disassembled the planet atom by atom-- and protons decay-- that maybe protons are unstable, and ... 08:42: Likewise, people ask whether rogue planets or rogue black holes, streaking through the Milky Way, could come in and collide with Earth. 09:00: I thought that a dwarf planet and an asteroid designation were mutually exclusive, they appear not to be. 07:41: ... Grey Goo-- the possibility that advanced nanobots might disassembled the planet atom by atom-- and protons decay-- that maybe protons are unstable, and in ... 07:00: ... episode of "Space Time." Last week, we talked about what might destroy planet Earth, and you guys have a lot to ... 00:52: When The Arwing is in a planetary atmosphere, a barrel roll is child's play, it's aerobatics 101. 08:42: Likewise, people ask whether rogue planets or rogue black holes, streaking through the Milky Way, could come in and collide with Earth.
	2015-03-11: What Will Destroy Planet Earth? 00:06: Will anything ever destroy this planet? 00:09: ... PLAYING] The physics of breaking something, including planets, is pretty straightforward-- just add enough energy to the individual ... 00:45: So realistically, could anything deliver that much energy to Earth and end the planet as we know it? 00:56: Could we nuke the planet to bits? 01:17: To wreck the planet, you'd need-- are you ready for this-- over one quadrillion Tsar-Bombs. 01:49: ... is huge but still only one billionth of the energy needed to blow up a planet. ... 02:34: Planets, on the other hand, do-- which brings me to colliding with Mars. 03:19: But in 1%, the inner planet orbits stretch out after about three billion years and Earth starts doing drive-bys of Venus and Mars. 04:09: See, another paper in the description works out that an Earth-like planet in a solar atmosphere would vaporize after a few million years. 05:54: ... galaxies, then inside planetary systems, inside planets themselves until literally, everything in a universe is ripped apart by ... 07:10: Zevin X points out that the real problem might be planetism. 03:19: But in 1%, the inner planet orbits stretch out after about three billion years and Earth starts doing drive-bys of Venus and Mars. 05:54: ... galaxies, then inside planetary systems, inside planets themselves until literally, everything in a ... 07:10: Zevin X points out that the real problem might be planetism. 00:09: ... PLAYING] The physics of breaking something, including planets, is pretty straightforward-- just add enough energy to the individual ... 02:34: Planets, on the other hand, do-- which brings me to colliding with Mars. 05:54: ... galaxies, then inside planetary systems, inside planets themselves until literally, everything in a universe is ripped apart by ...
	2015-03-04: Should We Colonize Venus Instead of Mars? 00:42: And that hurts our sister planet, not just in culture and media but in space policy. 01:42: The planet itself has some significant advantages over Mars. 02:33: ... if we have the technological means to add water to a planet's surface and oxygen to its air, changing the planet's surface gravity is ...
	2015-02-18: Is It Irrational to Believe in Aliens? 00:44: Based on recent analyses of exoplanet data, we can now also estimate, without totally guessing, how common planets are that might support life. 00:50: It looks like it's around one habitable planet per star, on average. 00:54: So 200 billion stars, 200 billion habitable planets. 00:59: ... need to know what percentage of the habitable planets would actually sprout life and then what percentage of those ... 01:08: Multiply these two probabilities by the 200 billion planets and, voila, you know how many Wookies, or Covenant, or Vulcans you should expect. 02:11: The argument says, look, 200 billion inhabitable planets, that's a huge number. 02:39: If the chances of intelligent life evolving are even lower, well, 200 billion is just the number of habitable planets in our galaxy. 02:45: If we sweep nearby galaxies into our planet account, we can add trillions more planets to compensate. 03:07: ... dating back to Copernicus, is rooted in the democratic notion that our planet, our Sun, our galaxy, none of them are ... 04:15: And we are just one species on one planet. 04:37: ... really is inevitable on the billions and billions of habitable planets, then where the ... 05:39: ... intelligent alien life never evolves on the billions of possible planets or that intelligent aliens evolve, none of whom ever spread out in any ... 06:53: I'll report any interesting findings on the next episode of "Space Time." Last week we asked, what planet is Super Mario World? 07:01: D. Moritz found that Sonica Hedgehog lives on a planet with about 5.6 Earth gees, Closer to a planet. 02:45: If we sweep nearby galaxies into our planet account, we can add trillions more planets to compensate. 00:44: Based on recent analyses of exoplanet data, we can now also estimate, without totally guessing, how common planets are that might support life. 00:54: So 200 billion stars, 200 billion habitable planets. 00:59: ... need to know what percentage of the habitable planets would actually sprout life and then what percentage of those ... 01:08: Multiply these two probabilities by the 200 billion planets and, voila, you know how many Wookies, or Covenant, or Vulcans you should expect. 02:11: The argument says, look, 200 billion inhabitable planets, that's a huge number. 02:39: If the chances of intelligent life evolving are even lower, well, 200 billion is just the number of habitable planets in our galaxy. 02:45: If we sweep nearby galaxies into our planet account, we can add trillions more planets to compensate. 04:37: ... really is inevitable on the billions and billions of habitable planets, then where the ... 05:39: ... intelligent alien life never evolves on the billions of possible planets or that intelligent aliens evolve, none of whom ever spread out in any ...
	2015-02-11: What Planet Is Super Mario World? 00:07: And is there any real-life planet where you could jump like Mario? 01:09: Now a planet's surface gravity has a huge effect on how high you can jump on that world. 01:19: ... on any given planet, there's a simple relationship between its g value, the maximum height ... 04:00: On a planet with eight times Earth's surface gravity, your blood is eight times as heavy. 04:17: Do any real-life planets have that large a g? 04:19: Well, g on a given planet is determined by a combination of that planet's mass and its radius. 04:36: ... gas giant planets, like Uranus, Neptune, and Saturn, don't have solid surfaces to stand on, ... 04:52: ... to planets outside the solar system are trickier, because astronomers don't have ... 05:12: Now, though the jury is still out, most models of planet formation also suggest that it's hard to have both a high g and a solid surface. 05:20: So what planet is Super Mario World? 05:23: Well, a planet with a solid surface where Mario could jump exactly the way he does in the game is unlikely to exist, at least in our universe. 05:47: ... and especially if you find a game that mimics the gravity of any actual planet, please let me know in the comments, along with your ... 05:12: Now, though the jury is still out, most models of planet formation also suggest that it's hard to have both a high g and a solid surface. 01:09: Now a planet's surface gravity has a huge effect on how high you can jump on that world. 04:17: Do any real-life planets have that large a g? 04:19: Well, g on a given planet is determined by a combination of that planet's mass and its radius. 04:36: ... gas giant planets, like Uranus, Neptune, and Saturn, don't have solid surfaces to stand on, ... 04:52: ... to planets outside the solar system are trickier, because astronomers don't have ... 04:19: Well, g on a given planet is determined by a combination of that planet's mass and its radius. 01:09: Now a planet's surface gravity has a huge effect on how high you can jump on that world.

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