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	2022-12-14: How Can Matter Be BOTH Liquid AND Gas? 00:03: ... is made of, or at extreme densities we get the nuclear matter of neutron stars. ...
	2022-11-23: How To See Black Holes By Catching Neutrinos 07:49: ... patch of sky in the constellation of cetus includes a lot of Milky Way stars, a lot of very distant galaxies, but there’s only one thing that is a ... 11:35: Supernovae, colliding neutron stars and black holes, tidal disruption events when black holes rip apart stars, you name it. 16:33: ... heavy elements are produced in supernovae or in colliding neutron stars by the R-process - basically bombarding lighter elements with ...
	2022-11-16: Are there Undiscovered Elements Beyond The Periodic Table? 03:28: Well, actually technetium is produced in nature - just like other heavy elements, in the core of massive stars. 03:36: Those elements eventually find their way into planets, which form from the guts of those stars after they explode as supernovae. 03:43: But technetium is so unstable that by the time the Earth pulled itself together from the detritus of dead stars, all the technetium was long gone.
	2022-11-09: What If Humanity Is Among The First Spacefaring Civilizations? 00:38: ... Stars will continue burning for another hundred trillion years, and the heat ... 00:52: At the same time, when we look at the sky we see… stars. 04:16: It turns out that most habitable stars are formed in a pretty short period of cosmic history. 04:29: And around 20 billion years in the future, there won’t be enough interstellar material left to form new stars. 05:51: If there are few hard steps, then civilizations emerge soon after their stars are formed. 07:49: ... stars, also known as red dwarfs, can live for thousands of times longer than ...
	2022-10-26: Why Did Quantum Entanglement Win the Nobel Prize in Physics? 15:43: We hope you find peace among the stars. 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! 01:25: ... a New York sized telescope - at this spot,   we have a star-sized telescope. The result is an amplification of the brightness of the ... 18:29: ... of stars or accretion disks. But perhaps in the cores of neutron stars   could get there. Also some transient phenomena - like supernovae, ... 15:45: ... 1/137 as   the universe cooled. By the time fhe first stars were formed ti was essentially as it is today. Radoslaw Garbacz ask What ...
	2022-09-28: Why Is 1/137 One of the Greatest Unsolved Problems In Physics? 08:22: ... a few percent different, carbon would never have formed  inside stars, making life ...
	2022-09-21: Science of the James Webb Telescope Explained! 04:03: The very first galaxies shone with intense ultraviolet light as the dense, young gas of the early universe collapsed into the first stars. 04:40: ... allows it to see the cool dust and gas that lives between the stars, as well as peer through that dust which normally blocks shorter ... 05:01: IR sensitivity lets us peer into the dusty whirlpools around new stars and watch the formation of planets in action.
	2022-08-17: What If Dark Energy is a New Quantum Field? 10:55: ... explanation 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 ...
	2022-08-03: What Happens Inside a Proton? 19:17: ... can I abuse the rules of reality to  survive past the death of the stars and live   to see the release of half life 3?” The ...
	2022-07-27: How Many States Of Matter Are There? 06:10: However in the very early universe everything was a quark-gluon plasma, and that may also be true in the cores of massive neutron stars. 10:57: Astrophysicists routinely model the galaxies as a sort of fluid of stars, where the interactions are not electromagnetic, but gravitational. 11:05: So, galaxies are fluids of stars which themselves are made of plasmas of hydrogen made of frozen nuggets of quark matter.
	2022-07-20: What If We Live in a Superdeterministic Universe? 12:29: Their first effort used the light from a pair of distant stars as proxies for Alice and Bob. 12:53: ... and Bob’s decisions except in the seemingly implausible scenario of stars talking to each other and conspiring against ...
	2022-06-30: Could We Decode Alien Physics? 15:07: ... speeds through  the dust and gas that lives between the stars. ...
	2022-06-22: Is Interstellar Travel Impossible? 01:31: But none ever manage to populate the galaxy because sending living creatures between the stars is so difficult that it’s just not worth it. 02:19: ... humans to travel the stars, travel time needs to at least be of order a human lifetime, which means ... 03:36: The space between the stars in our galaxy is far from empty. 06:41: This stuff comes from heavy elements that are fused in the cores of massive stars and ejected in supernovae or in the winds from giant stars. 10:30: Moderate shielding is sufficient for nearby stars, and the ability to repair shielding might get us to more distant parts of the galaxy. 15:02: Amy, thanks for helping us reach for the stars. 02:19: ... humans to travel the stars, travel time needs to at least be of order a human lifetime, which means ... 04:38: We’re going to send a starship to the Proxima Centauri with the aim of getting them there in a generation, and hopefully alive. 09:49: So we can minimise the additional weight by making our starship as long and narrow as possible. 10:56: One that could result in our starship reaching its destination perfectly intact, but carrying a dead crew. 13:09: ... accelerate txo relativistic speeds, at least for our early iterations of starship propulsion ... 10:56: One that could result in our starship reaching its destination perfectly intact, but carrying a dead crew. 02:35: ... Breakthrough Starshot program proposes to send a train of tiny craft powered by solar sails, ... 09:56: ... viability of crewed missions, but rather on missions like Breakthrough Starshot where the “spaceship” is a wafer-thin chip for which a millimeter ... 02:35: ... Breakthrough Starshot program proposes to send a train of tiny craft powered by solar sails, which ... 04:02: ... glorious star-spanning future depends on the answer to a rather mundane question: can a ship ...
	2022-06-01: What If Physics IS NOT Describing Reality? 13:41: ... within our galaxy’s gravitational well.   It’ll interact with stars, kicking them up to  higher orbits while its own orbit decays. In ... 15:25: ... Kosa asks about actual collisions between  stars when galaxies merge. Given that most of the   galaxy is empty ... 13:41: ... within our galaxy’s gravitational well.   It’ll interact with stars, kicking them up to  higher orbits while its own orbit decays. In ... 15:25: ... ratio between the stars.   Glancing collisions can result in stars merging,  which increases the mass and also rejuvenates the   star ...
	2022-05-25: The Evolution of the Modern Milky Way Galaxy 01:41: ... tracked the positions and motions of more  than a billion Milky Way stars. We’re now able   to calculate a detailed and dynamical map of ... 02:19: ... arms. It orbits in the same direction as all the   disk stars once every 230 Million years. In the  center we have the bulge ... 03:22: ... early galaxies were messy and mostly small,   and formed stars furiously. These clumps fell  together and spun each other up into ... 04:41: ... reconstruct the   details of such a chaotic process? The stars from  every previous merger are mixed all across the   ... 05:11: ... review the evidence. Item 1: Stars that  join the Milky Way at the same time, like during   ... 05:58: ... on their own aren’t really enough to tell if   two stars came from the same galactic snack. So Evidence item number 2: If ... 06:57: ... to do with the moon of Saturn. Gaia  is able to identify the stars from this merger   because of the satellite’s incredible  ... 07:58: ... gas clouds tend to collapse into thin gas disks, and then produce stars that share that ... 08:29: ... special happened to the Milky   Way to create it. It’s made of stars, not gas,  and these stars orbit just a little faster   on ... 09:11: ... during  the merger with Gaia-Enceladus.   While the stars of Gaia Enceladus got mixed  into the halo, the crazy gravitational ... 10:12: ... easy for astronomers to pick out the little stripe  of stars, like GD-1: a globular cluster that’s in   the process of being ... 11:10: ... Like  beating a drum or plucking a guitar string,   the stars oscillate up and down in the galactic  plane, making a very faint ... 08:29: ... elements. That suggests   they formed before the thin disk stars - around 9  billion years ago, plus or minus a billion ... 10:12: ... biggest, like the Helmi stream,   contain tens of millions of stars and  wrap in a full loop around the Milky ... 04:41: ... reconstruct the   details of such a chaotic process? The stars from  every previous merger are mixed all across the   Milky Way ... 06:57: ... to reconstruct   detailed orbits of Milky Way stars. The stars from  Gaia-Enceladus move in highly elongated orbits in   the inner ... 03:22: ... early galaxies were messy and mostly small,   and formed stars furiously. These clumps fell  together and spun each other up into ... 09:11: ... slamming into each other  kicked up the orbits of many of the stars in   the Milky Way’s original thin disk to create  the thick disk. ... 08:29: ... Way to create it. It’s made of stars, not gas,  and these stars orbit just a little faster   on orbits that are more inclined than ... 11:10: ... Like  beating a drum or plucking a guitar string,   the stars oscillate up and down in the galactic  plane, making a very faint ripple ... 05:11: ... also called metallicity - by looking  for the dips and spikes in a star’s spectrum   that result from specific elements sucking up  or producing light ... 00:00: ... in the southern hemisphere  and you’ll see too: the several billion stars   of the large and small magellanic clouds in  their slow death ... 08:29: ... the Milky Way disk, leading  to the aforementioned thickness. Those stars   are different in other ways - for example, they tend to have fewer ...
	2022-05-18: What If the Galactic Habitable Zone LIMITS Intelligent Life? 01:07: ... mysteries of the universe? In   a galaxy of 200+ billion stars, why don’t we see  any other signs of technological life? This is ... 04:32: ... also not unusual. The Kepler   mission demonstrated that most stars have planets  - at least in the local part of the ... 05:24: ... not so fast. There is another factor to consider.   Stars have habitable zones, but so do galaxies.  There are huge regions ... 05:52: ... Stars are mostly made out of hydrogen  and helium, with trace amounts of ... 06:28: ... of these heavy elements are produced in  massive stars and then spread through the galaxy   in supernova explosions. ... 07:36: ... formed  planets. No chance for life yet. However these   stars were incredible atom factories, rapidly  burning their way up the ... 08:01: ... next generation of stars had some metals, and so for the first time had the chance to ... 09:26: ... the core the worst place in  the galaxy. The extreme density of stars will   have led to frequent close encounters between  ... 10:04: ... gas. Towards the rim we see metal-poor gas and   metal-poor stars that they formed - again, not  the most likely places to find ... 12:04: ... but it’s also not the most typical.   Fewer than 10% of stars formed in the Milky Way  have optimal conditions for the ... 08:01: ... so for the first time had the chance to build   planets. These stars fell towards the center of  the still-collapsing gas cloud like pebbles ... 12:04: ... but it’s also not the most typical.   Fewer than 10% of stars formed in the Milky Way  have optimal conditions for the development ... 06:28: ... the galactic habitable zone   is that enough massive stars have  lived and died in that region.   But while we’re talking ... 12:04: ... down to a percent or two  if we ruled out the erratic red dwarf stars, the   most common star type. That still leaves billions  of possible ... 09:26: ... the core the worst place in  the galaxy. The extreme density of stars will   have led to frequent close encounters between  systems. In our ... 04:32: ... pretty ordinary   G-type main sequence star. Around 5% of the stars  in the Milky Way are G-types, which means there   are several ... 07:36: ... primordial generation of stars  were unpolluted by heavy elements,   which means they couldn’t ... 12:04: ... worse. This team   discovered something unexpected: of all the stars  in the Galaxy that could currently support life,   most of ... 08:01: ... of supernovae. As  Moiya mentioned, having excessive exploding stars   in one’s neighborhood can be a problem. Radiation  may lead to ... 10:04: ... Eventually the disk of  gas converted itself into a disk of stars.   It took some time for the emerging spiral disk  to seed itself with ...
	2022-05-04: Space DOES NOT Expand Everywhere 01:24: ... to move around due to nearby gravitational influences - planets orbit stars, stars orbit in the mutual gravity of their galaxies, galaxies whirl and ... 05:19: ... galaxy growing but overcome by the gravitational attraction between the stars? ... 01:24: ... around due to nearby gravitational influences - planets orbit stars, stars orbit in the mutual gravity of their galaxies, galaxies whirl and collide in ...
	2022-04-20: Does the Universe Create Itself? 17:39: ... hole with the mass of our observable universe - adding together all the stars, dark matter, other black holes, etc - then it’s event horizon is the same ...
	2022-03-30: Could The Universe Be Inside A Black Hole? 08:51: Now real stars don’t look like this.
	2022-03-23: Where Is The Center of The Universe? 18:31: ... found around 60 similar signals that were not clearly associated with stars and had radio frequency spacing similar to Earthly ...
	2022-03-08: Is the Proxima System Our Best Hope For Another Earth? 00:25: A world that would be humanity’s first destination  when we would finally venture to the stars. 01:15: Father Jean Richaud saw two stars instead of one, these days dubbed Rigel Kentaurus and Tolimar, a binary pair bound in an 80 year waltz. 01:28: ... allowing astronomers to watch alpha-cen sway relative to the background stars as Earth orbited the ... 01:47: The two stars were so near and so familiar - both within 10% or so of our own Sun’s mass. 02:10: Forward another century, and a Scotsman named Robert Innes photographed the southern stars from Johannesburg to track their galactic wanderings. 03:22: ... resulting from electron transitions in the atoms and molecules of the star’s ... 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. 04:22: ... the wavelengths of all the star’s light are stretched as the star moves away from us and compressed as it ... 04:42: ... the Doppler effect is only  produced by the component of the star’s velocity that’s either directly towards us or away from us - in the ... 05:26: Nonetheless the Kepler mission found 2600+ exoplanets this way, and extrapolating from that revealed that most stars host planetary systems. 06:18: Such a short orbital period, combined with the star’s mass, gave them an orbital radius for the exoplanet of around 20 times smaller than the Earth’s. 06:37: ... zone of the star - just the right distance for the intensity of the star’s radiation to potentially allow water to exist in liquid ... 07:28: The discovery of this exoplanet - Proxima Centauri B - or Proxima-B - was just the first of this little star’s surprises. 08:30: We have a bona fide planetary system in at least one of the stars in the Alpha-Cen system. 11:22: ... convection through the star’s body generates crazy magnetic storms, which can cause the star to have ... 03:22: ... resulting from electron transitions in the atoms and molecules of the star’s atmosphere. ... 11:22: ... convection through the star’s body generates crazy magnetic storms, which can cause the star to have ... 04:15: Planets make stars wobble, and that motion induces something called Doppler shift in the star’s emission lines. 05:26: Nonetheless the Kepler mission found 2600+ exoplanets this way, and extrapolating from that revealed that most stars host planetary systems. 04:22: ... the wavelengths of all the star’s light are stretched as the star moves away from us and compressed as it moves ... 06:18: Such a short orbital period, combined with the star’s mass, gave them an orbital radius for the exoplanet of around 20 times smaller than the Earth’s. 06:37: ... zone of the star - just the right distance for the intensity of the star’s radiation to potentially allow water to exist in liquid ... 07:28: The discovery of this exoplanet - Proxima Centauri B - or Proxima-B - was just the first of this little star’s surprises. 04:42: ... the Doppler effect is only  produced by the component of the star’s velocity that’s either directly towards us or away from us - in the “radial” ... 04:15: Planets make stars wobble, and that motion induces something called Doppler shift in the star’s emission lines. 13:51: It’s the breakthrough Starshot program - something we’ve discussed previously.
	2022-01-27: How Does Gravity Escape A Black Hole? 02:08: ... that’s been confirmed when gravitational waves from colliding neutron stars reach us at about the same time the corresponding electromagnetic ... 16:14: ... unless they’re close together, then the magnets will obviously form stars and ... 02:08: ... that’s been confirmed when gravitational waves from colliding neutron stars reach us at about the same time the corresponding electromagnetic radiation ...
	2022-01-19: How To Build The Universe in a Computer 00:47: ... chaotic gravitational and  hydrodynamic interactions of countless stars and gas and dark matter particles over billions of future ... 01:40: He arrayed 37 light bulbs on a plane, each one representing billions of stars in a spiral galaxy disk. 02:15: He would then measure light at each bulb, which told him the summed “gravitational” pull on that group of stars. 04:37: But if we want realistic simulations of say, a galaxy with its billions of stars, we need to do a bit better. 07:24: Adaptive particle meshes can be used to add higher resolution where needed - say, where the stars have higher density or structure. 07:57: ... from beyond, where it rides the disk, fragments and collapses into stars, it forms  whirlpools and jets around  new stars and black ... 08:58: SPH can even be used to do galaxy formation,   where the stars themselves are  treated as a type of fluid. 09:22: In your galaxy simulation you might need a separate prescription to describes how stars age and die. 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. 09:22: In your galaxy simulation you might need a separate prescription to describes how stars age and die. 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.
	2021-12-29: How to Find ALIEN Dyson Spheres 03:47: ... has expanded to reprocess a significant fraction of its home star’s light, then not only could we detect that shift with our current ... 05:48: Dyson and Sagan etc’s calculations were for a full Dyson sphere - one that reprocesses all of their star’s light. 05:56: But many civilizations may find it totally adequate to only partially harvest their star’s light. 06:11: Or really any so-called megastructure that intercepts a decent fraction of the star’s light. 06:24: To understand how to spot such a thing, let’s learn a thing or two about stars. 06:30: Stars are surprisingly simple beasts, for the most part ruled by laws of physics that we’ve understood for centuries. 07:41: If we carefully broke up the star’s light with spectrographs spanning a huge wavelength range, we might be able to see two distinct thermal spectra. 07:52: But that’s a lot of work even for a single star, and we probably need to search a huge number of stars to hope to find even a single Dyson sphere. 08:03: Fortunately, even a crude observation of a star’s color and brightness can tell us that something is up. 08:27: I mentioned that most stars show a tight relationship between certain properties. 08:50: ... stars that are in the primes of their lives - those powered by fusing hydrogen ... 09:03: ... Stars drive off the main sequence when they expand into giants at the ends of ... 09:20: At visible wavelengths a star’s color might not change much - it’ll just look dimmer. 09:46: ... years, calculate that a partial sphere that intercepts only 1% of its star's light could shift the visible-to-infrared color by a factor of more than ... 10:01: ... teams have used successively more advanced instruments to look for stars that were both too dim and too infrared, time and again they came up ... 10:28: The team started by looking for stars that were a little too faint for their visible-light color - below the main sequence. 10:39: Then they checked whether these stars had an excess of light in the infrared. 12:12: ... we can't identify a single Dyson sphere's effects around individual stars at distant galaxies. But what if a civilization in one of those has ... 12:44: Now this is a bit tougher, because galaxies aren’t as simple as stars. 08:03: Fortunately, even a crude observation of a star’s color and brightness can tell us that something is up. 09:20: At visible wavelengths a star’s color might not change much - it’ll just look dimmer. 09:03: ... Stars drive off the main sequence when they expand into giants at the ends of their ... 03:47: ... has expanded to reprocess a significant fraction of its home star’s light, then not only could we detect that shift with our current telescopes, it ... 05:48: Dyson and Sagan etc’s calculations were for a full Dyson sphere - one that reprocesses all of their star’s light. 05:56: But many civilizations may find it totally adequate to only partially harvest their star’s light. 06:11: Or really any so-called megastructure that intercepts a decent fraction of the star’s light. 07:41: If we carefully broke up the star’s light with spectrographs spanning a huge wavelength range, we might be able to see two distinct thermal spectra. 09:46: ... years, calculate that a partial sphere that intercepts only 1% of its star's light could shift the visible-to-infrared color by a factor of more than ... 11:33: At this point, our surveys have found no evidence for star-spanning megastructures.
	2021-12-20: What Happens If A Black Hole Hits Earth? 01:23: ... and those little fluctuations in density eventually collapsed into stars and galaxies instead of black ... 01:49: ... at the earliest of times, while still leaving plenty of matter left for stars. ... 02:50: ... these black holes then they’d frequently pass in front of more distant stars, magnifying those stars’ light with gravitational ... 03:25: ... to the masses of large asteroids. Black holes this big don’t devour stars like Cygnus X-1, and they don’t warp the passage of light from distant ... 02:50: ... they’d frequently pass in front of more distant stars, magnifying those stars’ light with gravitational ...
	2021-12-10: 2021 End of Year AMA! 00:02: ... relativity so when you look out there you see you know nearby you see stars okay twinkling those stars are roughly where they appear to be but the ...
	2021-11-17: Are Black Holes Actually Fuzzballs? 09:25: ... as the neutron star’s gravitational field is so intense that atomic nuclei are crushed into a ... 15:45: So it is our honor to honor Ernest H Anderson Jr., who passed away in 2018, and has returned to the stars. 09:25: ... as the neutron star’s gravitational field is so intense that atomic nuclei are crushed into a soup of ...
	2021-11-10: What If Our Understanding of Gravity Is Wrong? 02:11: In most galaxies, stars are somewhat concentrated  towards the centers, which means gravity should weaken towards the outskirts. 02:18: That means the orbital velocities of stars out there should be lower in order to keep them in orbit. 06:47: ... on the dark matter halo  while the luminosity depends on the stars. ... 10:01: ... of matter,   which would, for example, make long-lived stars ... 12:07: ... RelMOND - relativistic MOND - works for galaxy clusters and keeps stars from exploding  - but the authors are ... 10:01: ... of matter,   which would, for example, make long-lived stars impossible. ...
	2021-10-05: Why Magnetic Monopoles SHOULD Exist 16:32: ... it smashes through the degeneracy pressure that supports white dwarf stars and instead produces a black hole or neutron ...
	2021-09-21: How Electron Spin Makes Matter Possible 15:48: ... Gorman says that he imagined that black holes would look more like dim stars rather than, well, black holes because they slingshot light around from ... 16:27: ... times! There was speculation that quasars could be swarms of neutron stars or supernova cascades or even bizarre objects flying at crazy speeds out ...
	2021-09-15: Neutron Stars: The Most Extreme Objects in the Universe 00:25: ... stars are arguably the strangest objects in the universe - if we don’t ... 02:35: ... through the magnetosphere we start to notice that the neutron star’s surface   is a little fuzzy. We’re seeing the star’s  ... 03:07: ... the neutron star’s atmosphere  is not made of atoms, rather it's a plasma,   ... 03:27: ... depending on how you define the edge of   space, the neutron star’s atmosphere is barely a meter thick, with most of the plasma ... 05:48: ... the real journey can begin as we  start to tunnel into the star’s interior.   We enter the outer crust of the star. Density ... 10:06: ... sort of like nuclear pasta mountains buried beneath   the star’s surface. These could be as tall as  10 centimeters. which doesn’t ... 11:29: ... which is probably an essential part of maintaining the neutron star’s enormous magnetic ... 12:23: ... completely into a quark gluon plasma. And we've talked about quark stars before. While these plasmas have been seen in   collider ... 03:27: ... depending on how you define the edge of   space, the neutron star’s atmosphere is barely a meter thick, with most of the plasma confined ... 03:07: ... the neutron star’s atmosphere  is not made of atoms, rather it's a plasma,   in which atoms ... 11:29: ... which is probably an essential part of maintaining the neutron star’s enormous magnetic ... 05:48: ... the real journey can begin as we  start to tunnel into the star’s interior.   We enter the outer crust of the star. Density only increases as we ... 10:06: ... hum at exactly one frequency- twice the  frequency of the neutron star’s rotation-   and gravitational wave astronomers are searching for these signals ... 03:27: ... most of the plasma confined to   a thin shell 10cm above the star’s surface. This is due to the insane gravity at that surface - which I’ll come ... 10:06: ... sort of like nuclear pasta mountains buried beneath   the star’s surface. These could be as tall as  10 centimeters. which doesn’t sound like ... 03:27: ... most of the plasma confined to   a thin shell 10cm above the star’s surface. This is due to the insane gravity at that surface - which I’ll come back to. ... 02:35: ... through the magnetosphere we start to notice that the neutron star’s surface   is a little fuzzy. We’re seeing the star’s  atmosphere. Similar to ... 00:25: ... metronomes of flashing light as these rapidly spinning stars sweep us with their jets as pulsars. And we’ve explored strange processes ... 02:35: ... neutron star’s surface   is a little fuzzy. We’re seeing the star’s  atmosphere. Similar to Earth’s atmosphere,   this layer of ... 00:25: ... count black holes   as actual objects. And honestly, neutron stars are even weirder than black holes in some ways.   We’ve talked ...
	2021-08-18: How Vacuum Decay Would Destroy The Universe 00:21: ... expansion rate, and has just the right particle properties to allow stars and   planets and people to exist. The habitability ... 08:30: ... the masses of the elementary particles.   The ability for stars to form and undergo  nuclear fusion, and the ability for ... 00:21: ... expansion rate, and has just the right particle properties to allow stars and   planets and people to exist. The habitability of our universe is ...
	2021-08-10: How to Communicate Across the Quantum Multiverse 14:53: ... out there, a common envelope binary system is one where the stars are so close together that they share an envelope - you can also ... 16:27: ... Persona asks what happens to the star’s magnetic fields after it goes supernova. And then guesses the correct ...
	2021-08-03: How An Extreme New Star Could Change All Cosmology 01:45: ... - or at least, what we thought we knew. When all but the most massive stars end their lives, they blast off their outer layers in their final fits ... 02:13: ... fast it’s spinning. Now we do expect white dwarfs to rotate. After all, stars rotate and so should their remnant cores. That spin should also increase ... 03:58: ... get an accurate measure of size. Size is hard to measure even for normal stars: most are so far away that even our highest-resolution telescope cameras ... 04:37: ... another factor at play there - how far away the star is. Measure the star’s brightness on the sky, factor in how much that brightness has been ... 05:01: ... is the hardest to measure. The most accurate way to get distances to stars is with stellar parallax. That’s when the motion of the Earth causes a ... 05:24: ... GAIA satellite changed that by measuring parallaxes for a billion stars across the Milky Way, and Zee was one of them. So we have its distance - ... 06:17: That’s true of planets and regular stars, but it’s not true of white dwarfs. 08:29: ... gets packed so close together that one of two things happen. If a dying star’s core exceeds the Chandrasekhar limit then it collapses into a neutron ... 08:48: ... just don’t see these extreme properties in the white dwarfs produced as stars ... 09:18: ... energy. We’ve seen the result of this with black holes and neutron stars when LIGO detected the gravitational waves from the last moment of those ... 09:51: ... it doesn’t just have the angular momentum from its spinning parent stars - it has the angular momentum from the orbits of the parent stars. This ... 15:55: ... asks whether magnetic fields have any measurable effect on the orbits of stars around the galaxy. Not directly. The galactic magnetic field is very ... 16:19: So the locations that stars formed may be influenced by magnetic fields, which in turn affects their orbits. So the answer is yes, sort of. 17:08: ... is no, although magnetic fields do have important effects on scales from stars to galaxies - they’re still much, much weaker than gravity. Some people ... 09:51: ... it doesn’t just have the angular momentum from its spinning parent stars - it has the angular momentum from the orbits of the parent stars. This ... 04:37: ... another factor at play there - how far away the star is. Measure the star’s brightness on the sky, factor in how much that brightness has been dimmed by ... 03:58: ... a function of its temperature, and you can measure temperature from the star’s color. ... 08:29: ... gets packed so close together that one of two things happen. If a dying star’s core exceeds the Chandrasekhar limit then it collapses into a neutron star or ... 08:48: ... just don’t see these extreme properties in the white dwarfs produced as stars die. ... 15:55: ... 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 the galactic ... 16:19: So the locations that stars formed may be influenced by magnetic fields, which in turn affects their orbits. So the answer is yes, sort of. 02:13: ... fast it’s spinning. Now we do expect white dwarfs to rotate. After all, stars rotate and so should their remnant cores. That spin should also increase as the ... 04:37: ... and you have its luminosity. Then luminosity plus temperature gives the star’s size. ... 03:58: ... so far so weird. The next step in the star-sleuth’s playbook is to get an accurate measure of size. Size is hard to measure ...
	2021-07-21: How Magnetism Shapes The Universe 06:00: The interstellar medium - the space between the stars - is scattered with tiny specks of dust produced in past supernova explosions. 10:00: Without that, those clouds would never be able to collapse all the way into stars. 10:05: And magnetic fields also facilitate star formation after stars die. 06:00: The interstellar medium - the space between the stars - is scattered with tiny specks of dust produced in past supernova explosions. 10:05: And magnetic fields also facilitate star formation after stars die.
	2021-05-25: What If (Tiny) Black Holes Are Everywhere? 03:45: ... gives us this nice picture of a far, far distant future in which the stars have gone out and we only have black holes, which one by one vanish in ... 07:22: The only way to make black holes in the modern universe is in the deaths of massive stars.
	2021-05-19: Breaking The Heisenberg Uncertainty Principle 09:13: ... away, and involving lower-mass mergers of black holes and neutron stars. ...
	2021-05-11: How To Know If It's Aliens 09:21: ... that it’s best explained by an alien megastructure eclipsing the star’s light. That claim was on the strength that no known natural phenomenon ...
	2021-04-21: The NEW Warp Drive Possibilities 00:51: And only 15 years after general relativity’s debut, the warp drive was invented, propelling humanity on its first journeys to the stars. 05:11: ... in all the matter in the visible universe to move a moderate-sized starship. ... 06:35: But I guess the dreams of wannabe starship captains are strong - because the work continued, and just recently two papers have claimed breakthroughs. 12:37: They’ll continue to try to “make it so” by exploring Einstein’s theory - hoping to build starship, but in the process learning how our universe works. 12:47: And possibly also building a starship, to propel humanity into the galaxy on waves of warped space time. 06:35: But I guess the dreams of wannabe starship captains are strong - because the work continued, and just recently two papers have claimed breakthroughs.
	2021-04-13: What If Dark Matter Is Just Black Holes? 01:39: ... twice the diameter of the Milky Way’s spiral disk, where most of the stars are ... 03:06: ... rule out black holes from the only reliable astrophysical source - dead stars. ... 03:16: We know black holes form from the remaining cores of the most massive stars, after they explode as supernovae. 03:21: ... maximum possible number of these black holes by estimating the number of stars that formed and died through cosmic ... 03:37: ... in those explosions, but the heavy elements forged in the cores of these stars during their ... 03:57: Also, if dark matter is produced as stars die, you’d expect its influence to increase over time. 04:07: ... gravity of dark matter was pulling matter together long before the first stars ever ... 06:30: I’m talking somewhere between a billion to a billion billion times more of them than there are stars in the universes.. 06:48: For example, they’d puncture white dwarfs and neutron stars on a regular basis. 06:53: ... through a white dwarf, but it would deposit enough heat to allow the stars' ultra dense carbon and oxygen to undergo nuclear ... 07:12: Neutron stars are a bit different. 07:22: But we see too few type 1a supernova and too many neutron stars for this to be a common phenomenon. 08:24: ... best way to search for MACHOs in our galaxy is to monitor the stars in the galactic bulge or in our neighboring galaxies to see if they ... 08:52: ... Clouds are especially good for this - the low level of microlensing of stars in these mini-galaxies has allowed us to rule out MACHOs between roughly ... 10:01: ... trickled to the center by now, and in the process flung less massive stars into higher ... 03:57: Also, if dark matter is produced as stars die, you’d expect its influence to increase over time. 06:53: ... through a white dwarf, but it would deposit enough heat to allow the stars' ultra dense carbon and oxygen to undergo nuclear ...
	2021-03-16: The NEW Crisis in Cosmology 00:22: ... Gaia mission and its unprecedented survey of a billion stars in the Milky Way.   And guess what - the tension is now even ... 02:07: ... to measure distances to nearby stars,   then more distant stars, then nearby  galaxies, then distant galaxies,  ... 03:13: ... variables are great standard candles, but they’re just stars, and are too faint to see   beyond a certain distance. In the ... 07:28: ... can use this same trick to measure the distance to stars. As the earth orbits the   sun over the course of the year, ... 08:03: ... measurements of Cepheids in the   Milky Way to turn these stars into standard candles and so founded our distance ... 07:28: ... the earth orbits the   sun over the course of the year, nearby stars appear to move relative to more distant stars.   That’s stellar ... 02:07: ... in the solar system - then use those to measure distances to nearby stars,   then more distant stars, then nearby  galaxies, then distant ... 07:28: ... of the year, nearby stars appear to move relative to more distant stars.   That’s stellar parallax, and our quest to measure it has been ...
	2021-03-09: How Does Gravity Affect Light? 11:43: ... enabled him to measure the slight offset in the apparent positions of stars around the sun, due to their light rays being “refracted” in the Sun’s ...
	2021-02-17: Gravitational Wave Background Discovered? 00:00: ... have detected 50 similar signals from merging black holes and neutron stars across the universe these sweep past the earth every few days causing ...
	2021-01-26: Is Dark Matter Made of Particles? 00:23: ... see the influence of dark matter in the orbits of stars and galaxies, in way light bends around galaxies and clusters, in the ... 01:13: Now it’s possible that dark matter is not particles - it could be black holes or failed stars or even weirder so-called “compact objects”. 04:21: They might collapse into dark matter galaxies or dark matter stars or dark matter people. 04:34: In fact, galaxies are really just shiny dustings of stars, sprinkled deep in the gravitational wells of massive reservoirs of dark matter.
	2020-12-22: Navigating with Quantum Entanglement 02:04: Across long distances, birds often rely on the sun or even the stars. 14:02: For more detail we would indeed need a whole episode Quantum fields asks what about neutron stars. 14:34: ... other hand if protons DO decay then the small proton content of neutron stars will decay into pions and neutrinos, leaking away some of the mass of ...
	2020-12-15: The Supernova At The End of Time 02:20: But first, there are many questions to be answered - like how do stars including our Sun end up as one of these “iron stars” in the first place? 02:33: Well not quite the very beginning, but on the timescales of iron stars pretty close to it. 02:39: ... a mere 13.7 billion years after the big bang, when one of these iron stars was in its extremely brief phase as a bright ball of hydrogen, bathing a ... 04:22: These faint but searing-hot stars appeared to have densities so high that a single cubic centimeter of their material weighed a literal ton. 05:05: Most eminent physicists of the era were coming to believe that the white dwarf should be the fate of all stars. 05:59: The star’s own electrons would be driven into its nuclei in a process called electron capture. 08:46: The result is an iron star - or an iron black dwarf - the hypothetical fate of all stars whose cores are beneath the Chandrasekhar limit. 09:13: But assuming protons are stable, we’ll reach a point where the universe consists of only iron stars and radiation. 09:20: ... those iron stars are also doomed - they’ll quietly become black holes themselves through ... 09:45: ... published in August this year, has found a way for some of these iron stars to end on a brighter note - as black dwarf ... 10:36: It immediately annihilates with one of those electrons, depleting the star’s supply. 11:12: They’ll leave behind smaller iron cores or a neutron stars. 11:16: ... the largest such stars, you should expect the first explosions to begin in 10^1100 years or so, ... 11:45: ... be at least one more interesting thing to look forward to - Iron stars exploding in unimaginably distant future of space ... 04:22: These faint but searing-hot stars appeared to have densities so high that a single cubic centimeter of their material weighed a literal ton. 11:45: ... be at least one more interesting thing to look forward to - Iron stars exploding in unimaginably distant future of space ... 02:20: But first, there are many questions to be answered - like how do stars including our Sun end up as one of these “iron stars” in the first place? 02:33: Well not quite the very beginning, but on the timescales of iron stars pretty close to it. 10:36: It immediately annihilates with one of those electrons, depleting the star’s supply.
	2020-10-27: How The Penrose Singularity Theorem Predicts The End of Space Time 00:34: ... even light from escaping its surface. Few people took these “dark stars” seriously - especially   when we learned that light didn’t ... 12:11: ... supermassive black hole by monitoring the   crazy orbits of stars in the galactic core. The work of Ghez and Genzel and other ...
	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. 03:44: 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. 03:58: This can be done at far infrared and submillimeter radio wavelengths where the star’s own glare doesn’t kill the signal. 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.
	2020-09-28: Solving Quantum Cryptography 14:24: Last week we talked about a highly speculative idea - lifeforms inside stars, formed from cosmic strings and magnetic monopoles. 15:10: Timescales may be driven by the timescale of the motion of plasma in the stars and by the size of these critters. 14:24: Last week we talked about a highly speculative idea - lifeforms inside stars, formed from cosmic strings and magnetic monopoles.
	2020-09-21: Could Life Evolve Inside Stars? 00:16: Oh, and here’s an extra crazy one - life composed of cosmic strings and magnetic monopoles, evolving in the hearts of stars. 01:03: ... monopoles - may evolve into complex structures, and even life, within stars. ... 06:58: And this is where stars come in. 07:00: Others have speculated that cosmic strings may get trapped inside stars in the process of star formation. 07:13: Depending on the stellar type and region, the insides of stars can be very turbulent places. 09:27: Or perhaps the nuclear reactions in the core proceed faster, hastening the dissipation of the star’s energy through space. 09:40: ... are a few stars in our modern surveys that don’t quite act as they should, however there ... 10:14: So are the stars filled with thriving ecosystems of critters built from fractured quantum fields? 09:27: Or perhaps the nuclear reactions in the core proceed faster, hastening the dissipation of the star’s energy through space. 10:14: So are the stars filled with thriving ecosystems of critters built from fractured quantum fields?
	2020-09-08: The Truth About Beauty in Physics 13:34: So today we're covering our episode on the future circular collider and on how we know the composition of stars. 13:42: In fact let's start with the stars. 14:47: ... of gas hanging out in space like a nebula - it will be illuminated by stars but you're not looking directly AT those stars through the ... 15:05: You won't see absorption unless you look directly through the cloud at one of those stars.
	2020-09-01: How Do We Know What Stars Are Made Of? 00:17: Science has long pondered the mysteries of the stars. 00:28: ... first thing you learn in astronomy is that the sun and the other stars are giant balls of fiery hydrogen and helium, powered by raging nuclear ... 00:51: We didn’t know what stars were made of nor where their energy came from. 01:24: She not only revolutionized our understanding of the stars, but she helped blaze a trail in astronomy and physics for the women who would come after. 02:45: Enough so that she knew what she wanted to research - she wanted to unlock the mysteries of the stars. 02:57: The secret to understanding the stars is not exactly in the light they send to us. 03:26: The colour of a star depends on that temperature - blue for hot stars, red for cooler stars, and sort of greenish-yellow for stars like our Sun. 05:48: ... - was going to take some serious advances in understanding how both stars and atoms work Fortunately help was at ... 06:13: ... that she could use to decode the complex patterns of absorption lines in stars. ... 07:27: Payne realized that it should be possible to translate a star’s absorption line pattern into measures of temperature and composition. 08:36: Cecilia Payne set about analyzing the many spectra of stars that had been observed at Harvard Observatory. 08:43: ... the relative abundances of the elements and found they varied between stars, but were generally similar to what we find on Earth’s surface - but with ... 09:13: Cecilia Payne had discovered what the sun and stars were made of. 09:50: By the way, the whole finding out what stars are made of thing wasn’t even the main point of Payne’s thesis. 09:56: She also developed a way to calculate the temperatures of stars just based on the absorption lines. 10:08: So, yeah, that’s how we know what the stars are made of. 10:13: At around the same time as Ceclia Payne was doing all of this, other scientists were figuring out the rest of the mysteries of the stars. 10:20: ... fusion thing just a few years earlier in 1920, but now knowing what stars are made of, he and others were able to develop a detailed theory of ... 10:33: Stars went from being utterly mysterious to one of the best-understood denizens of the universe. 10:46: ... here’s to the stars - both types - Cecilia Payne-Gaposchkin, star astrophysicist, and also ... 12:17: Mark, we've talked about a lot of stars today, so it’s fitting we end on you, the starriest star of all. 12:24: Thanks for helping us to .... shoot for the stars? 10:46: ... here’s to the stars - both types - Cecilia Payne-Gaposchkin, star astrophysicist, and also the ... 07:27: Payne realized that it should be possible to translate a star’s absorption line pattern into measures of temperature and composition. 03:26: The colour of a star depends on that temperature - blue for hot stars, red for cooler stars, and sort of greenish-yellow for stars like our Sun. 12:17: Mark, we've talked about a lot of stars today, so it’s fitting we end on you, the starriest star of all.
	2020-08-24: Can Future Colliders Break the Standard Model? 14:19: ... parasitic, and generally unhealthy relationships between the stars - from novae to black widow ... 15:53: David Kosa asks how would we describe the interaction of two merging stars of equal mass whose combined mass exceeds the Chandrashekar limit? 16:17: That happens in the cores of massive stars when they die. 14:19: ... parasitic, and generally unhealthy relationships between the stars - from novae to black widow ...
	2020-08-17: How Stars Destroy Each Other 00:02: Forget TMZ - Here on Space Time we have all the latest details on the dysfunctional, explosive relationships between the stars. 00:15: Let me tell you a tale of a pair of star-crossed … well, stars. 00:20: When our galaxy was a little younger there were two ordinary stars - perhaps not unlike our sun, and they danced together in binary orbit. 02:07: ... more than half of all stars existing in binary orbits, it’s inevitable that many stellar remnants ... 02:16: ... the novae produced by white dwarfs, to X-ray binaries created by neutron stars and black holes - and much weirder things ... 05:02: Those are what you get when the most massive stars die. 08:23: The neutron star’s jets sweep it hundreds of times per second, slowly blasting away its gas. 09:25: Finally that core is expected to break up in the neutron star’s tidal field and be scattered into the void. 09:51: Eventually, the core of the white dwarf reaches a temperature of hundred of millions of Kelvin, and the star’s carbon and oxygen can begin to fuse. 10:54: ... that seemed to straddle the mass between black holes and neutron stars, and which will change the way we think about whichever of those it turns ... 12:10: Dead stars aren’t the only way to make black holes. 12:32: ... black holes could be less massive than black holes that come from stars, so might explain this weird teensy possible black ... 13:27: Compared to a black hole or neutron star, regular stars are giant puffed up balls. 00:20: When our galaxy was a little younger there were two ordinary stars - perhaps not unlike our sun, and they danced together in binary orbit. 09:51: Eventually, the core of the white dwarf reaches a temperature of hundred of millions of Kelvin, and the star’s carbon and oxygen can begin to fuse. 05:02: Those are what you get when the most massive stars die. 02:07: ... more than half of all stars existing in binary orbits, it’s inevitable that many stellar remnants will end up ... 08:23: The neutron star’s jets sweep it hundreds of times per second, slowly blasting away its gas. 09:25: Finally that core is expected to break up in the neutron star’s tidal field and be scattered into the void.
	2020-08-10: Theory of Everything Controversies: Livestream 00:00: ... the size of the planet jupiter and put it in orbit around the neutron stars stuff like this so you can make a lot of fun um estimates uh on that ...
	2020-07-28: What is a Theory of Everything: Livestream 00:00: ... gravity you know something like something involving perhaps neutron stars or or something like that how can we get creative anyone who has a ...
	2020-07-20: The Boundary Between Black Holes & Neutron Stars 00:10: And we just did - an object on the boundary between neutron stars and black holes, which promises to reveal the secrets of both. 03:26: Now that’s only been seen once before - with the merger of two neutron stars in 2017 - which we obviously covered back then. 03:34: ... across the electromagnetic spectrum - energy released as the neutron stars tore themselves apart in their collision before they collapsed into a ... 03:47: ... it an enormous amount of information about what happens when neutron stars collide - and we’re going to be using that information in just a ... 04:39: To understand that, we have to understand a bit more about black holes and neutron stars. 04:44: A neutron star is what’s left after some massive stars explode as supernovae. 05:42: ... fact neutron stars are on the verge of being black holes, which by definition have an ... 06:13: But neutron stars are NOT made of normal matter. 07:00: As you increase a neutron star’s mass, its phantom event horizon grows while its actual surface shrinks. 07:49: ... of the state of matter in the neutron star determines how a neuron star’s size changes with mass - and that’s what determines the maximum possible ... 08:43: ... masses come from pulsars - cosmic lighthouses that result from a neutron star’s precessing jets sweeping past the ... 09:47: ... weird that there seems to be a gap in masses between the biggest neuron stars and the smallest black holes, but actually we very much expect ... 09:58: New black holes are formed when the most massive stars die and the core is too big to become a neutron star. 10:04: But you don’t get this smooth transition from neutron stars to black holes. 10:08: Like I said earlier, a neutron star forms when a star’s core collapses, but most of the material rebounds as a supernova explosion. 10:28: Based on our calculations and simulations of how stars die, that minimum black hole mass of 5 Suns seems about right. 10:41: ... be a neutron star then we’re going to have to rework our models of how stars die - or find some other way to make extra-teensie black ... 11:08: Each will be rich in information on the nature of stars, and gravity, and strange quantum states of matter. 03:47: ... it an enormous amount of information about what happens when neutron stars collide - and we’re going to be using that information in just a ... 10:08: Like I said earlier, a neutron star forms when a star’s core collapses, but most of the material rebounds as a supernova explosion. 09:58: New black holes are formed when the most massive stars die and the core is too big to become a neutron star. 10:28: Based on our calculations and simulations of how stars die, that minimum black hole mass of 5 Suns seems about right. 10:41: ... be a neutron star then we’re going to have to rework our models of how stars die - or find some other way to make extra-teensie black ... 04:44: A neutron star is what’s left after some massive stars explode as supernovae. 07:00: As you increase a neutron star’s mass, its phantom event horizon grows while its actual surface shrinks. 08:43: ... masses come from pulsars - cosmic lighthouses that result from a neutron star’s precessing jets sweeping past the ... 07:49: ... of the state of matter in the neutron star determines how a neuron star’s size changes with mass - and that’s what determines the maximum possible ... 03:34: ... across the electromagnetic spectrum - energy released as the neutron stars tore themselves apart in their collision before they collapsed into a black ...
	2020-07-08: Does Antimatter Explain Why There's Something Rather Than Nothing? 06:27: ... thought gas was expensive. So we’re going to wait a while to be powering starships with antimatter engines. Fortunately, you don’t need anything like a ...
	2020-06-22: Building Black Holes in a Lab 00:16: ... one. Nonetheless, the evidence for their reality is overwhelming. Stars orbiting in crazy slingshot orbits around a patch of nothingness in the ... 12:23: ... until we’re able to travel to the stars, or to build - and hopefully control - real black holes in the lab, the ... 00:16: ... one. Nonetheless, the evidence for their reality is overwhelming. Stars orbiting in crazy slingshot orbits around a patch of nothingness in the center of ...
	2020-06-15: What Happens After the Universe Ends? 07:06: ... all stars will die and their remnants will decay - black holes will evaporate by ...
	2020-06-08: Can Viruses Travel Between Planets? 08:01: So yeah, stars sneeze, you might want to maintain 6 light years distance. 10:24: All of that said, radiation from stars is probably our best hope for obliterating space viruses. 14:44: ... cluster where it seems like that the dark matter is separated from the stars and therefore can’t be due to just having the wrong theory of ... 08:01: So yeah, stars sneeze, you might want to maintain 6 light years distance.
	2020-05-04: How We Know The Universe is Ancient 01:35: ... Were they blobs of gas in the Milky Way, or vast, distant groups of stars - other “Milky Ways”, or as Immanuel Kant called them, island universes. ... 07:07: ... the distances to the galaxies wrong. It turns out that Cepheid variable stars come in two types, with two different period-luminosity ... 08:58: ... because it’s based on comparing the expected, true brightnesses of stars with the apparent, distance-dimmed brightness. It seems fair to assume ... 09:39: ... been counting bright clouds of hydrogen gas - so-called HII regions - as stars, which threw their numbers off. It was a young astronomer named Alan ... 01:35: ... Were they blobs of gas in the Milky Way, or vast, distant groups of stars - other “Milky Ways”, or as Immanuel Kant called them, island universes. ... 09:39: ... while we thought we’d found globular clusters - ancient, dense groups of stars - that were 15 billion years old. As bad as finding rocks older than the ... 01:35: ... Hubble figured out the distances to these objects by watching their stars pulse. He located a star type called a Cepheid variable, whose pulsation rate ...
	2020-04-28: Space Time Livestream: Ask Matt Anything 00:00: ... gold we used to think it was forged in the hearts of the most massive stars before they well as they exploded as as they exploded yeah collapsed ...
	2020-04-22: Will Wormholes Allow Fast Interstellar Travel? 15:35: ... Belhaj asks about the interstellar medium - isn't the space between the stars and galaxies an empty void? Actually no. Particularly within a galaxy, ...
	2020-04-14: Was the Milky Way a Quasar? 00:47: ... also swarms with smaller black holes, searing hot clouds of gas, massive stars right on the edge of going supernova, and some of the most energetic ... 04:06: These “cosmic rays” can then collide with nuclei in the gas between the stars - again, mostly the protons of hydrogen. 06:47: ... or close interaction with another galaxy - then that gas can form stars at a really insane rate across the galaxy. We call these events ... 07:09: ... by an enormous number of supernova explosions because the most massive stars produced in the starburst die - rather explosively - very ... 07:43: All of those supernovae would have had to leave remnants behind - neutron stars and black holes. 07:49: The neutron stars should be seen as pulsars, and there just aren’t enough in that region to account for a starburst of the required magnitude. 04:06: These “cosmic rays” can then collide with nuclei in the gas between the stars - again, mostly the protons of hydrogen. 07:09: ... by an enormous number of supernova explosions because the most massive stars produced in the starburst die - rather explosively - very ...
	2020-03-31: What’s On The Other Side Of A Black Hole? 10:35: ... have somewhere to come from. But real black holes form from collapsing stars - there’s no white hole in their past. And within those black holes, any ...
	2020-03-24: How Black Holes Spin Space Time 01:44: ... everything that went into forming it. That includes the rotation of the star’s core that collapsed into the black hole in the first place, and the ...
	2020-02-18: Does Consciousness Influence Quantum Mechanics? 14:26: ... Predmyrskyy also asked about this in the comments: if axions come from stars, would galaxies lose their dark matter and fly apart once the stars ... 14:51: ... axions produced in stars now would be a tiny fraction of the mass we see in dark matter - in fact ... 14:26: ... from stars, would galaxies lose their dark matter and fly apart once the stars died? ...
	2020-01-20: Solving the Three Body Problem 11:21: ... evolution of dense regions of the universe, where three-body systems of stars or black holes may form and then disintegrate very ...
	2020-01-13: How To Capture Black Holes 00:59: ... and astrophysics predicted black hole mergers. When two very massive stars are in binary orbit with each other, they may end their lives to leave a ... 02:50: ... of thousands of stellar-mass black holes. These are the remnants of dead stars, typically a few to a few tens times the mass of the Sun. They rained ... 03:34: ... in such a dense environment. Regular glancing encounters with other stars or black holes can tear binary pairs apart before they can spiral ... 02:50: ... rained down on the galactic center over billions of years as massive stars formed and died in the surrounding galactic core. This has been a theoretical ...
	2020-01-06: How To Detect a Neutrino 07:51: ... 𝘩𝘪𝘨𝘩 𝘴𝘺𝘯𝘵𝘩) ♪ enough to leave a bit of leftover stuff to produce the stars and galaxies and ♪ ♪ particle physicists that we see around us ...
	2019-12-17: Do Black Holes Create New Universes? 00:37: Tweak them too much and life, stars, galaxies, the universe as we know it wouldn’t exist. 02:43: Now by happy chance there’s a correlation between making lots of black holes and making life - both require stars. 02:52: The universe that is better at making stars is better at making planetary systems is better at making us. 05:49: In our modern universe, black holes are made when the most massive stars explode as supernovae. 05:59: So we should expect our universe to be optimized for producing as many of the most massive stars as possible. 06:13: Stars are formed when giant clouds of gas collapse under their own gravity. 06:37: ... elements and molecules allow clouds to cool and stars to form much more quickly, and of these, carbon monoxide is by far the ... 06:48: ... addition, gas needs to be shielded from the heating effect of other stars - and that seems to require the presence of tiny particles of ice and ... 07:00: ... without carbon, oxygen, water, and chemistry in general, far fewer stars and so far fewer black holes would form - and of course these factors ... 07:16: ... given infinite time these will eventually outnumber those produced by stars or stellar black ... 09:09: ... massive stars die, they actually mostly produce neutron stars - planet sized balls of ... 09:20: Black holes only form when the neutron stars is above a certain mass limit. 09:25: Now it may be that in the cores of the most massive neutron stars, some particles can convert into strange quarks. 09:48: That in turn means less massive neutron stars would be able to collapse into black holes. 09:54: ... quark mass should be optimized to make the cutoff between neutron stars and black holes as low as ... 10:14: So, if this universe is optimized for black hole production then there should be no neutron stars more massive than 2 solar masses. 11:13: ... ... but what if it was, I dunno, beryllium and boron that helped stars form - or other elements that were useless to ... 06:48: ... addition, gas needs to be shielded from the heating effect of other stars - and that seems to require the presence of tiny particles of ice and ... 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 ... 05:49: In our modern universe, black holes are made when the most massive stars explode as supernovae. 11:13: ... ... but what if it was, I dunno, beryllium and boron that helped stars form - or other elements that were useless to ... 00:37: Tweak them too much and life, stars, galaxies, the universe as we know it wouldn’t exist.
	2019-12-09: The Doomsday Argument 02:24: But it’s a good thing ours IS low because otherwise our universe would have blown itself up too quickly for stars and life to ever form. 14:57: ... most obvious example is that regular gravitational fields around stars and galaxies can be positively curved patches in a flat or hyperbolic ...
	2019-11-18: Can You Observe a Typical Universe? 00:45: ... we realized that our sun is a typical example out of 100s of billions of stars in the Milky Way, and that the Milky Way is an ordinary galaxy among ... 05:50: ... interesting that's happened since - from the formation of stars and galaxies to the evolution of life - has been powered by the slow ... 06:01: ... life in a state of extreme disorder and high entropy - iron stars, black holes, and a mist of cold elementary particles, not very ...
	2019-11-11: Does Life Need a Multiverse to Exist? 01:44: ... would be vastly different - and probably unable to produce galaxies, or stars, or ... 05:05: The vast majority of carbon in the universe is produced in the cores of massive stars. 05:36: Other slight changes in nuclear fine tuning would also massively reduce the amount of oxygen that stars produce. 06:12: ... if it were stable, this stuff would be like superfuel for stars - meaning all stars in the universe would have burned out before life ... 06:21: ... unstable, eliminating one of the key steps in the fusion process inside stars - so stars like our sun wouldn’t burn at ... 06:42: With weaker gravity, diproton-burning stars could last longer, and with stronger gravity, fusion could skip the deuterium step. 07:05: The stability of atoms and the rate of fusion in stars and in the early universe depends on the balance between electromagnetism and the strong force. 08:25: ... the masses of the elementary particles, is just right for things like stars and complex matter to form in our ... 06:12: ... if it were stable, this stuff would be like superfuel for stars - meaning all stars in the universe would have burned out before life ever ... 06:21: ... unstable, eliminating one of the key steps in the fusion process inside stars - so stars like our sun wouldn’t burn at ... 06:12: ... if it were stable, this stuff would be like superfuel for stars - meaning all stars in the universe would have burned out before life ever got a ... 05:36: Other slight changes in nuclear fine tuning would also massively reduce the amount of oxygen that stars produce.
	2019-11-04: Why We Might Be Alone in the Universe 04:31: ... I mean rocky planets about the size of the Earth in orbit around stars very similar to the Sun at the right distance to sustain liquid water on ...
	2019-10-21: Is Time Travel Impossible? 05:59: And in fact we'd need entire planets – perhaps entire stars converted to negative energy to do this.
	2019-10-07: Black Hole Harmonics 01:00: But real black holes are created in the violent deaths of massive stars, and there’s nothing clean about that. 12:52: We’re seeing many, many mergers of black holes and neutron stars, and we’re learning an awful lot about these objects.
	2019-09-30: How Many Universes Are There? 06:31: ... have restarted its accelerating expansion too quickly for galaxies and stars and life to ever ... 17:20: But what about around other stars? 17:29: That's right, other stars don't have planets - they have exoplanets.
	2019-09-23: Is Pluto a Planet? 01:00: ... shape, black holes based on how they feed and how they're oriented, stars based on their color and brightness, and planets by… well, by a set of ... 01:36: If you were an ancient astronomer like say, Ptolemy, the planets were the asteres planetai, the wandering stars. 01:44: ... and the moon - basically anything that moved relative to the background stars. ... 03:06: New wandering stars were discovered in the centuries following Newton. 07:04: And yet some brown dwarfs orbit other, more massive stars just like planets do. 01:00: ... shape, black holes based on how they feed and how they're oriented, stars based on their color and brightness, and planets by… well, by a set of ...
	2019-08-12: Exploring Arecibo in VR 180 01:02: ... off planets and asteroids as far as Jupiter Or send messages to the stars. Let's check out the dish below We're now directly beneath the dish at ...
	2019-07-25: Deciphering The Vast Scale of the Universe 00:25: That’s a quadrillion stars, and as many planetary systems. 03:07: For example, consider two stars – one bright one dim to our eyes. 03:14: Now, perhaps those stars are identical, and the bright one is just closer to us. 03:25: Now there are some clever ways to measure distances to stars within the Milky Way galaxy. 03:39: ... and dimmed with a repeating period that is mathematically related to the stars’ absolute ... 06:23: ... our solar system behind, we’re zipping past the hundreds of billions of stars of our Milky Way galaxy at a few hundred billion times the speed of ... 06:34: ... we’ve only mapped the locations and velocities of around 1% of those stars, that gives us an incredible understanding of the shape and motion of our ... 06:57: There’s Andromeda, its incredible distance first revealed to Hubble through its pulsing Cepheid variable stars. 08:16: ... well as the earliest galaxies or even black holes or worlds around other stars, Mt. Wilson's Hooker Telescope wouldn't cut ... 03:39: ... and dimmed with a repeating period that is mathematically related to the stars’ absolute ...
	2019-07-01: Thorium and the Future of Nuclear Energy 02:49: ... or natural gas plants or you know on a Lunar or Martian settlement or a starship that same modularity Poses perhaps the biggest risk if small thorium ...
	2019-06-20: The Quasar from The Beginning of Time 03:40: For example, viewed in visible light, the Andromeda galaxy shows us newborn stars. 05:53: Now, that gas collapsed into the very first stars, then the very first galaxies. 05:58: Those stars eventually melted away the remaining hydrogen in a process called reionization, leaving a crystal-clear universe. 06:07: But this quasar shines out from the era of those first stars before they'd finished the job of reionization. 05:58: Those stars eventually melted away the remaining hydrogen in a process called reionization, leaving a crystal-clear universe.
	2019-06-17: How Black Holes Kill Galaxies 00:08: ... even tighter relationship between the Black Hole mass and the speed that stars are moving in their random orbits within galactic bulge the so called, ... 01:35: ... they live in their Gravitational influence should only extend to the stars right at the very centre of the galaxy they definitely aren't directly ... 02:54: ... a ready mass of seed Black Holes formed by the very first generation of stars they would fall to the centres of their local wispy protor galaxy and ... 05:24: ... formation and haven't had any for long time The short-lived hot massive stars that give Spiral galaxies, like the Milky way, their blue-white sheen ... 07:21: ... for star formation in the later case is because hot gas can't form new stars gas has to cool down before the force of gravity can cause it to ... 11:24: ... time we talked about all the cool elements that get made when neutron stars ... 13:12: ... may be that some neutron stars are actually "Strange Stars" whose nuclear material is composed of ... 11:24: ... time we talked about all the cool elements that get made when neutron stars collide. ... 07:21: ... not just in largest galaxies but across the universe after the first stars formed around 150 million years after the big bang the rate of star formation ... 05:24: ... but from what we can tell those giant galaxies should've kept forming stars Giant reservoirs of gas flowed into those clusters from the outside Universe ...
	2019-06-06: The Alchemy of Neutron Star Collisions 00:00: ... our bodies were created in the nuclear furnaces and explosive deaths of stars that lived in the ancient universe in recent years it's become clear ... 00:34: ... produced in onion shells by nuclear fusion in the cores of very massive stars during the last phases of their lives and that elements heavier than ... 02:47: ... spotted the space-time ripples from the merger of a pair of neutron stars many of the world's great telescopes monitored the subsequent ... 00:34: ... following supernova explosion that latter process is well understood the stars dead core collapses and protons are converted to neutrons the surrounding ... 02:47: ... talked about the cosmic dark ages that mysterious time before the first stars formed in our universe let's see what you had to say BloodyAlbatross reasonably ...
	2019-05-16: The Cosmic Dark Ages 00:04: ... in the stelliferous era. Somewhere between 10 and 1000 billion trillion stars fill the observable universe with light. But there was a time before the ... 00:24: ... see the past in motion. In fact we’re able to see some of the first stars and galaxies to ever form. But if we look beyond, both in distance and ... 02:31: ... Stars that formed from that gas would be the next source of light, and those ... 02:52: ... believed that the first stars formed around 150 million years after recombination when tiny ... 03:52: ... galaxies – proto-galaxies – formed stars at a prodigious rate, and around these galaxies bubbles of ionized ... 05:45: ... or emits a radio photon with a wavelength of 21cm. When the first stars ignited they heated the surrounding gas, which caused it to absorb more ... 06:54: ... that first generation of giant stars? They did more than kickstart reionization and produce the first ... 02:52: ... believed that the first stars formed around 150 million years after recombination when tiny fluctuations in ... 05:45: ... universe. The amount of that redshift tells us the when the very first stars formed – because it was those stars that enabled this absorption in the first ...
	2019-04-24: No Dark Matter = Proof of Dark Matter? 00:03: ... as with many of his wiki's predictions like the existence of neutron stars and gravitational lensing this wasn't taken seriously until decades ...
	2019-03-28: Could the Universe End by Tearing Apart Every Atom? 00:05: ... ripped to shreds, Stars obliterated cats and dogs living together and then tragically separated ... 09:26: ... the effect of phantom energy is stronger than the gravity binding the stars ... 09:48: There are some millions of years of fun as we watch those galaxies disassemble and the constellations of stars in the Milky Way fly apart. 12:53: ... - the universe will still end in a long cold heat death in which the stars of our galaxy wink out become black holes and then evaporate over an ... 00:05: ... ripped to shreds, Stars obliterated cats and dogs living together and then tragically separated by the ...
	2019-03-20: Is Dark Energy Getting Stronger? 03:19: ... at the earliest of times when the CMB was released long before the first stars ... 04:02: Type-1a supernovae– which result from exploding white dwarf stars. 03:19: ... at the earliest of times when the CMB was released long before the first stars formed. ...
	2019-03-06: The Impossibility of Perpetual Motion Machines 13:47: ... mostly come from our galaxy - there's a lot from the dust in between the stars, and also from individual electrons either bumping into other charged ...
	2019-02-20: Secrets of the Cosmic Microwave Background 12:34: ... about 5% of the mass and energy that's all of the atoms in all of the stars in all of the galaxies basically everything you can see The remaining ...
	2019-02-07: Sound Waves from the Beginning of Time 00:11: ... the stars, these galaxies form constellations, Hidden patterns that echo the ... 05:01: At 380,000 years, the plasma hit a critical temperature of 3000 Kelvin, around the surface temperature of the coolest red dwarf stars. 06:46: ... matter, hydrogen and helium could begin the long work of collapsing into stars and galaxies work of collapsing into stars and galaxies as the universe ... 13:58: ... to wait 10^(10^25) years for the first quantum tunneling to turn iron stars into black holes, and way, way longer than that for anything ...
	2019-01-24: The Crisis in Cosmology 03:18: ...giant stars, during the last phases of their lives. 04:41: These result when white dwarfs, ancient remnants of dead stars,... 17:07: ...and presumably reassemble itself into the stars, spaceships, monkeys,... that originally fell in.
	2019-01-09: Are Dark Matter And Dark Energy The Same? 01:28: They should scatter their stars into the void.
	2018-12-12: Quantum Physics in a Mirror Universe 00:02: ... with the sort of technology being developed for the breakthrough starshot program so surely alien civilizations with any sort of technological Li ...
	2018-12-06: Did Life on Earth Come from Space? 00:37: ... of the journey one way for a budding microbial astronaut to travel the Stars is via Luther panspermia basically be attached to a rock that travels ...
	2018-11-21: 'Oumuamua Is Not Aliens 00:24: To us, it looked like a faint spot of light moving quickly relative to the fixed stars. 02:26: ... certainly expect there to be a bunch of space junk floating between the stars, probably ejected in the violent early stages of formation of planetary ... 05:37: It may also explain why we saw something at all given that natural space debris the size of Oumuamua should be much rarer between the stars. 08:56: For example, it may be that stars release their Oort Clouds, when they die. 09:22: ... or gravitational interaction into a trajectory that will send it to the stars. ... 08:56: For example, it may be that stars release their Oort Clouds, when they die. 05:27: And the breakthrough starship program is planning to use a lightsail as our first interstellar probe. 10:29: On the other hand, the breakthrough starshot lightsails are aiming at 20% light speed for a 20 year journey to the Alpha Cen system.
	2018-10-31: Are Virtual Particles A New Layer of Reality? 16:52: They were apparently orbiting a center of mass that wasn't even between the stars.
	2018-10-25: Will We Ever Find Alien Life? 00:36: ... short, in a galaxy of hundreds of billions of stars, each of which having billions of years to spawn life and civilization, ... 00:54: If aliens can travel between the stars, why haven't they visited? 01:55: This number allows us to figure out the fraction of stars that have planets. 01:59: Essentially, all stars do. 05:33: A team of astronomers scoured the GAIA data looking for stars that were unusually faint for their stellar type. 05:40: They looked at 8,000 stars and exactly one of those stars had a brightness significantly lower than expected. 05:47: ... star has a binary companion which may have caused a wobble in the star's position and that, in turn, may have messed with the star's parallax ... 06:09: But GAIA's upcoming third data release will expand this study from 8,000 to a million stars. 07:23: ... factors like the rate of star formation and the fraction of these stars that form habitable worlds, biological factors like the frequency of the ... 05:47: ... in the star's position and that, in turn, may have messed with the star's parallax distance determination and the determination of its power output, i.e., ...
	2018-10-10: Computing a Universe Simulation 05:40: ... the size of a picturesque European nation with the mass of the heaviest stars in the universe and with the storage capacity to register every atom in ... 13:41: The gravitational waves start to get strong before the neutron stars even make contact.
	2018-10-03: How to Detect Extra Dimensions 01:07: A pair of neutron stars spiralled together and merged. 01:11: These superdense remnants of dead stars churned the fabric of space and time in their death spiral. 01:22: Unlike merging black holes, which are invisible, merging neutron stars explode spectacularly. 09:58: ... electromagnetic signal from these merging exploding neutron stars allowed us to measure its distance completely independently to the ... 01:11: These superdense remnants of dead stars churned the fabric of space and time in their death spiral. 01:22: Unlike merging black holes, which are invisible, merging neutron stars explode spectacularly. 01:07: A pair of neutron stars spiralled together and merged.
	2018-09-12: How Much Information is in the Universe? 00:19: Hundreds of billions of galaxies, each with hundreds of billions of stars, each with rather a lot of particles in them. 00:25: ... then there's all the stuff that isn't stars-- the dark matter, black holes, planets, and the particles, and radiation ...
	2018-08-23: How Will the Universe End? 00:06: We live in an unusual age, the age when the stars still shine. 00:47: The Era of Stars will be over. 02:13: ... merger with the Andromeda Galaxy, and, finally, to the death of the last stars in the ... 02:32: ... Galaxy comprised of nothing but stellar remnants, the ultradense neutron stars and black holes from long-extinct massive stars, as well as the white ... 02:51: Those white dwarfs will fade to black in only several billion years, far shorter than the several trillion-year lives of those stars. 03:48: So at this point in the universe's future history, the Age of Stars has passed and no starlight will ever shine again. 04:05: But neutron stars and white-- or, by now, black-- dwarfs are made of degenerate matter. 04:23: Believe it or not, many of those black dwarfs will still have planetary systems from their days as regular stars. 04:49: As stars randomly pass close to each other, planets are flung into the blackness. 05:28: Heavier bodies, mostly neutron stars and black holes, sink towards the center. 05:33: ... to an estimate by Freeman Dyson, 90% to 99% of our galaxy's stars will be scattered into the void in something like 10 to the power of 18 ... 07:13: Some will be the remnant black holes of individual stars that were flung from galaxies long ago. 10:11: Black dwarfs decay into iron stars-- still degenerate and insanely dense, but now perfect balls of iron. 10:23: But even iron stars can't last forever. 10:26: The same process of quantum tunneling eventually transport a star's material toward its center. 10:32: Iron stars evolve into neutron stars. 11:27: This same process will nail all of the neutron stars too. 05:33: ... when the universe is a million times older than the age of the last stars' death. ... 10:32: Iron stars evolve into neutron stars. 02:32: ... massive stars, as well as the white dwarfs left from lower-mass stars, including the recently extinguished red ... 10:26: The same process of quantum tunneling eventually transport a star's material toward its center. 04:49: As stars randomly pass close to each other, planets are flung into the blackness.
	2018-06-20: The Black Hole Information Paradox 11:54: They were glimpsed as dark stars in the mathematics of Isaac Newton's law of universal gravitation.
	2018-05-16: Noether's Theorem and The Symmetries of Reality 12:05: Each time, stars will have moved slightly, but they'll have moved in extremely predictable ways. 12:10: ... fitting laws of motion to the stars' five-year trajectory, there's only a very narrow trajectory of extremely ...
	2018-05-09: How Gaia Changed Astronomy Forever 00:34: Its primary goal is to map the stars of the Milky Way with a scale and precision orders of magnitude greater than ever before. 00:42: Gaia's predessecor, Hipparcos, cataloged 120,000 stars. 00:46: Gaia blows this out of the water, with positions, colors, and brightnesses of nearly 1.7 billion stars. 01:04: Gaia can pin down a star's position to the equivalent of a human hairs width at 1,000 kilometers. 01:15: As we'll see, this precision allows Gaia to measure true distances and true velocities for 1.3 billion of its stars. 01:47: As it traverses its orbit, Gaia detects the tiny shifts in the positions of stars due to this motion, a phenomenon called stellar parallax. 02:07: Coupled with its incredible position measurements, this enables Gaia to measure distances to stars as far away as the galactic center. 02:19: For example, combining distance with a star's apparent brightness gives us its true to luminosity. 02:50: Location on this diagram can tell us about a star's mass, size, fusion activity, and even its past and future evolution. 02:58: For example, stars on this diagonal band-- the so-called, main sequence-- are in the primes of their lives, fusing hydrogen into helium. 03:06: After which, lower mass stars will become red giants, before leaving behind white dwarf remnants. 04:04: These are stars near the ends of their lives, now burning helium in their. 04:09: We can even watch variable stars dance along the HR diagram as their brightness' change. 04:28: The stars all move in their own orbits around the galactic core. 04:36: ... but Gaia's incredible astrometry revealed the change in positions of stars over the five years of its ... 04:45: This gives the velocities of the stars in the plane of the sky. 05:00: Combining motion on the sky and Doppler shift, gives the full three-dimensional velocities for these billion stars. 05:22: We can see the rotation of the Milky Way through the red and blue Doppler shift of the stars. 05:53: ... the current velocities and positions of the stars, we can actually wind the clocks backwards and forwards, to see where ... 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. 06:20: We can potentially, trace the origins of these stars, allowing us to find solar systems that came from the same stellar nurseries. 06:27: ... by constraining the distances to stars, we can get better measurements on the sizes of those stars, and thus, ... 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. 07:06: For example, we can study stretched out groups of stars, called stellar streams. 07:11: These dynamically connected flows of stars, once bound together as a globular clusters or dwarf galaxies. 07:34: And on top of all of this, Gaia doesn't only study stars. 08:48: Last week, we talked about the last stars that will shine in our universe-- the humble, red dwarf. 09:21: Red dwarfs are just a very low mass stars. 06:20: We can potentially, trace the origins of these stars, allowing us to find solar systems that came from the same stellar nurseries. 02:19: For example, combining distance with a star's apparent brightness gives us its true to luminosity. 07:06: For example, we can study stretched out groups of stars, called stellar streams. 04:09: We can even watch variable stars dance along the HR diagram as their brightness' change. 02:50: Location on this diagram can tell us about a star's mass, size, fusion activity, and even its past and future evolution. 01:04: Gaia can pin down a star's position to the equivalent of a human hairs width at 1,000 kilometers. 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.
	2018-05-02: The Star at the End of Time 00:10: How long will life persist as the stars begin to die? 00:47: And finally, our heirs or successors find new homes among the stars after the Sun's final death and transformation into a dim white dwarf. 01:20: And the deepest wells of accessible energy in the universe are stars. 01:29: To know the future of life, we must understand the life cycles of the longest-lived stars in the universe. 01:51: Stars generate energy, fusing hydrogen into helium in their cores. 02:21: ... the rate of fusion depends very sensitively on temperature, more massive stars with their hotter cores burn through their fuel much, much more ... 02:31: The most massive stars live only a few million years. 02:36: Stars less massive than the Sun burn through their fuel much more slowly. 02:41: ... so let's get a little crunchy and figure out the lifespan of red dwarf stars, also known as "M dwarfs." We observe that a red dwarf with 10% of the ... 03:04: Actually, wrong-- stars like our Sun can only burn the hydrogen in their cores. 04:20: Just like the Sun, the cores of red dwarf stars shrink and heat up over time. 04:37: An interesting thing about red dwarfs is they don't expand as they brighten, unlike more massive stars. 04:52: This is because the light produced by stars comes from the heat glow of their surfaces. 05:42: But as these stars heat up, their spectrum shifts. 06:26: Well, long before the first red dwarfs approach the ends of their lives, there will be no other living stars left in the galaxy. 06:33: ... new Sun-like stars will be born in the Milky Way/Andromeda collision four billion years ... 07:43: We don't know yet whether life can evolve around red dwarf stars. 08:15: Those stars will have long-frozen worlds in the outer parts of their solar systems. 08:38: ... one last long renaissance of life as we huddle in the warmth of the last stars to burn in the darkening end of space ... 09:34: Yeah, dark matter is expected to be more evenly spread through the galaxy than things like stars and black holes. 10:06: Well, the answer is that we can constrain the size of the Milky Way central black hole, Sagittarius A*, because we can see stars in orbit around it. 01:51: Stars generate energy, fusing hydrogen into helium in their cores. 05:42: But as these stars heat up, their spectrum shifts. 06:26: Well, long before the first red dwarfs approach the ends of their lives, there will be no other living stars left in the galaxy. 02:31: The most massive stars live only a few million years. 04:20: Just like the Sun, the cores of red dwarf stars shrink and heat up over time.
	2018-04-25: Black Hole Swarms 00:24: The stars are so densely packed that the night sky would be 500 times brighter than our own. 00:35: It flings nearby stars into extreme slingshot orbits. 02:11: Black holes form when the most massive stars end their lives in spectacular supernova explosions. 02:37: Even after blowing off most of their mass in a supernova, these black holes are still heavier than most stars. 02:51: As a black hole orbits the galaxy, it tugs on its neighboring stars. 02:55: Those stars are accelerated towards the black hole and can gather behind it in a gravitational wake. 03:07: The black hole can also slingshot stars outwards, losing momentum in that process, too. 03:50: They're like ancient, extremely dense mini-galaxies, containing millions of stars. 05:35: The brightest X-ray binaries are aggressively gobbling up their companion stars, but that ravenous phase probably doesn't last all that long. 10:00: Juxtaposed stars asks whether, theoretically, you could build an engine to extract power from gravitational waves via the sticky bead method? 11:05: I don't know, maybe a cosmic scale wall of neutron stars with two gaps in it? 10:00: Juxtaposed stars asks whether, theoretically, you could build an engine to extract power from gravitational waves via the sticky bead method? 03:07: The black hole can also slingshot stars outwards, losing momentum in that process, too.
	2018-04-18: Using Stars to See Gravitational Waves 01:07: ... if these black holes formed in the deaths of massive stars, which we think they must, then they should weigh in at between 5 and 15 ... 02:59: ... what they tell us about neutron stars, more observations like this should allow us to figure out where the ... 03:35: ... the binary orbits just before merger, which for black holes and neutron stars clocks in at a few to maybe 1,000 orbits per second in the last ... 04:34: ... as the faint hum of thousands of binary pairs of white dwarfs, neutron stars, and black holes long before they ... 05:41: ... pulsars, neutron stars with jets that sweep past the Earth as the star processes, resulting in ... 06:44: Some scientists are even trying to see how gravitational waves should interact with stars. 07:21: ... be able to dump some of their energy into matter, for example, into stars. ... 07:32: Stars oscillate at particular frequencies. 08:03: A similar effect may cause white dwarf stars in binary orbits to explode as they absorb gravitational radiation from their own orbits. 03:35: ... the binary orbits just before merger, which for black holes and neutron stars clocks in at a few to maybe 1,000 orbits per second in the last ... 07:32: Stars oscillate at particular frequencies.
	2018-04-11: The Physics of Life (ft. It's Okay to be Smart & PBS Eons!) 01:04: Stars always burn out. 10:10: ... the most random possible state, little eddies of order, like galaxies, stars, planets, and life naturally ...
	2018-03-28: The Andromeda-Milky Way Collision 00:33: It's two and 1/2 million light years away and host to a trillion stars. 01:35: But being so far away, you can't see individual stars in Andromeda without a good size scope. 02:01: In the mid 1700s, he hypothesized that Andromeda was an island universe, a vast sea of stars distant to our own. 02:27: The first incontrovertible evidence came when Edwin Hubble calculated its distance by watching the pulsation of stars in Andromeda. 04:32: They mapped the locations of thousands of stars in Andromeda between 2002 and 2010 and compared them to background galaxies. 04:40: Then they averaged the observed motion of all of those stars and removed the effects due to the rotation of Andromeda and the motion of the sun. 05:06: They used simulations of the gravitational interactions of millions of particles representing groups of stars and dark matter. 06:09: Gravitational interactions with stars slingshots those stars into larger orbits or even completely out of the galaxy. 06:52: Well, for one thing, we don't expect any collisions between stars. 06:56: The average distance between stars is around 100 billion times greater than the average size of a star. 08:37: ... our dynamical evolving universe, when we have a neighbor whose visible stars revealed its great distance, and whose spiral structure helped us guess ... 09:15: Last week, we talked about a stunning new result in astrophysics, the detection of the first stars to ever form. 09:40: ... the radio signal from the whole sky to measure their signal of the first stars. ... 09:49: ... the sky and so create images of the structures in which those first stars were forming, presumably some sort of proto-galactic ... 02:01: In the mid 1700s, he hypothesized that Andromeda was an island universe, a vast sea of stars distant to our own. 08:37: ... our dynamical evolving universe, when we have a neighbor whose visible stars revealed its great distance, and whose spiral structure helped us guess the shape ... 06:09: Gravitational interactions with stars slingshots those stars into larger orbits or even completely out of the galaxy.
	2018-03-21: Scientists Have Detected the First Stars 00:00: [MUSIC PLAYING] What do the first stars in the universe, dark matter, and superior siege engines have in common? 00:28: That's the case with the recent discovery of the earliest stars in the universe. 00:34: In a nature paper published just a few weeks ago, Judd Bowman and collaborators, report a signal from the very first stars to form in our universe. 02:13: Before long, some of that early hydrogen gas collapsed to form the very first stars, long before the first galaxies formed. 02:20: ... ultraviolet light from those stars shifted the equilibrium so that the electron spin temperature became ... 04:03: That period represents the time between the birth of the very first stars to the onset of very active black hole growth. 02:13: Before long, some of that early hydrogen gas collapsed to form the very first stars, long before the first galaxies formed. 02:20: ... ultraviolet light from those stars shifted the equilibrium so that the electron spin temperature became connected ...
	2018-03-07: Should Space be Privatized? 10:37: Stimuli asked why stars get brighter as they age if their fuel is depleting. 11:02: [INAUDIBLE] wants to know how the least mass of stars, red dwarfs, die. 12:04: ... stars consume their fuel thousands of times more slowly than the sun, which ... 11:02: [INAUDIBLE] wants to know how the least mass of stars, red dwarfs, die. 06:17: Then, there's Russian billionaire Yuri Milner with his breakthrough Starshot Program.
	2018-02-21: The Death of the Sun 00:43: Like living things, stars have a life cycle. 01:09: The most massive stars live only for hundreds of thousands to millions of years, and die in spectacular explosions called supernovae. 03:52: While the stars outer layers of hydrogen are expanding and cooling, the core continues to collapse until it hits a quantum mechanical limit. 09:18: ... sports cars and, perhaps, safer vessels to the planets and even to the stars. ... 01:09: The most massive stars live only for hundreds of thousands to millions of years, and die in spectacular explosions called supernovae. 03:52: While the stars outer layers of hydrogen are expanding and cooling, the core continues to collapse until it hits a quantum mechanical limit.
	2018-01-31: Kronos: Devourer Of Worlds 00:41: It's here that stars are born. 00:45: So in short, essentially all stars form in these stellar nurseries. 00:58: And we have no idea where its sibling stars might be. 01:02: However, if the gravitational connection between a pair of stars is strong enough, they might be ejected from the cluster as a binary pair. 01:12: Around half of all stars are binaries. 01:14: Binary stars typically have the same chemical composition as each other, having formed from the same cloud. 01:49: ... numbers of near-invisible stellar objects like black holes and neutron stars, as well as the distribution of gas and dark ... 02:06: They also allow us to test to what degree stars that formed in the same cloud share a chemical signature. 02:26: They're so, well, widely separated that it's hard to tell if a given pair of stars is actually gravitationally bound. 02:52: They identified plenty of stars that are close enough together that they could be gravitationally bound. 03:10: ... how the team came upon HD240430 and HD240429, Kronos and Krios, two stars nearly two light-years apart from each other, about 326 light-years from ... 03:24: They're both G-type stars like our sun. 03:29: The stars' velocities tell us that they're moving in lockstep together around the galaxy. 03:49: Stellar spectra are thick, with sharp emission and absorption features that result from electron transitions in atoms in the star's atmosphere. 04:04: In astro-speak, they tell us the star's metallicity, although for an astronomer, anything heavier than helium is called a metal. 04:43: These stars definitely formed from the same molecular cloud. 06:18: Lithium gets depleted in the early years of stars like the sun. 06:51: We now know that binary stars can have very different metallicities to each other. 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. 03:49: Stellar spectra are thick, with sharp emission and absorption features that result from electron transitions in atoms in the star's atmosphere. 00:45: So in short, essentially all stars form in these stellar nurseries. 04:04: In astro-speak, they tell us the star's metallicity, although for an astronomer, anything heavier than helium is called a metal. 01:14: Binary stars typically have the same chemical composition as each other, having formed from the same cloud. 03:29: The stars' velocities tell us that they're moving in lockstep together around the galaxy.
	2018-01-24: The End of the Habitable Zone 01:00: All stars brighten as they age and they deplete their fuel. 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. 01:00: All stars brighten as they age and they deplete their fuel. 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.
	2018-01-17: Horizon Radiation 12:28: Last week, we talked about the sounds that stars make-- the wonderful worlds of helio and asteroseismology. 12:38: Loki and Alex ask whether seismic activity in neutron stars can be used to probe their interior properties. 12:46: Neutron stars certainly seem to experience star quakes-- massive releases of energy, as the star's ion crust cracks. 13:11: Several of you asked where the sounds of stars we played at the end of the last episode came from. 13:32: The frequency spectra for resonant oscillations of several stars were shifted to a range audible to human hearing. 13:44: ... Justice, No Peace wonders whether stars may actually be speaking, considering Penrose's quantum brain ... 14:30: Second, stars aren't complex in the sense that Penrose means. 14:45: All that said, I love the idea of stars twinkling meaningfully at each other from across the galaxy. 12:46: Neutron stars certainly seem to experience star quakes-- massive releases of energy, as the star's ion crust cracks. 14:45: All that said, I love the idea of stars twinkling meaningfully at each other from across the galaxy.
	2018-01-10: What Do Stars Sound Like? 00:14: Believe it or not, we can now map the interiors of stars by listening to their harmonies as they vibrate with seismic waves. 00:22: [MUSIC PLAYING] Stars are among the best understood objects in astrophysics. 00:49: ... the core, the way energy flows to the surface, and even the life span of stars. ... 01:00: These models are largely built around what little we can learn from the light we receive directly from the surface of stars. 01:13: Well, we may not see light from beneath the stellar surface, but another type of wave travels freely through stars. 01:23: You see, stars have a dynamical complexity far exceeding the simplest predictions of the equations describing stellar structure. 01:33: ... oscillations, natural resonant frequencies that carry information about stars impenetrable ... 01:44: Stars ring like bells. 01:54: The fast-growing field of asteroseismology uses these oscillations to probe the interiors of the distant stars. 02:03: When we try to understand other stars, we always start with our sun. 02:07: While the distance stars are infinitesimal points of light to even our best telescopes, the surface of the sun can be resolved in incredible detail. 02:46: Stars also support p-waves. 02:53: Because stars are fluid rather than solid, they don't support shear waves. 03:14: In stars, these waves occur below the surface, g-waves, and on the surface, f-waves. 03:24: However, it's the pressure waves-- the p-waves-- that really dominate in stars like the sun. 03:41: They start as traveling waves that can move throughout the stars in a structure. 06:46: Seismological studies of distance stars-- asteroseismology-- is much more difficult. 07:17: ... red giant stars, asteroseismology has been used to determine the fusion activity in their ... 07:45: Future planet hunting satellites, like Tess and Plato, will continue this work with higher precision and for many more stars. 07:52: Most stellar seismology is focused on learning about the average global structure of stars. 08:41: Stars sing. 09:09: Because the science of asteroseismology can now translate the messages of stars twinkling at us from across space time. 11:24: Because there are no stars that could possibly explode that way for hundreds of light years. 11:45: GRBs from exploding stars are estimated to have jets with conical opening angles of between 2 and 20 degrees. 06:46: Seismological studies of distance stars-- asteroseismology-- is much more difficult. 07:17: ... red giant stars, asteroseismology has been used to determine the fusion activity in their dying cores, ... 01:33: ... oscillations, natural resonant frequencies that carry information about stars impenetrable ... 01:44: Stars ring like bells. 08:41: Stars sing. 09:09: Because the science of asteroseismology can now translate the messages of stars twinkling at us from across space time.
	2017-12-20: Extinction by Gamma-Ray Burst 01:01: ... collision with Andromeda, or the final burning out of the last stars, or the evaporation of the last black hole and decay of the last ... 03:25: The observed faint flash of gamma rays from exploding stars can last anywhere from a couple of seconds to a few minutes. 03:34: Short-duration bursts that last less than two seconds are caused by merging neutron stars. 06:50: ... on the rates of GRBs we see in other galaxies and on the population of stars in the Milky Way, it's estimated that every billion years, Earth finds ... 08:26: It's the star's rotational axis that defines the direction of the jet. 08:30: But the orbital axis of a binary system and the rotational axis of its stars are often correlated, so we may have dodged a bullet in this case. 08:53: There are definitely no stars in that range that could explode anytime soon. 12:16: And some stars will be sling-shotted out of the galaxy by the two supermassive black holes of Andromeda and the Milky Way as they fall together. 08:26: It's the star's rotational axis that defines the direction of the jet. 11:53: ... asks whether there's a chance that some stars/solar systems will be ejected from the galaxy when the Milky Way collides with ...
	2017-12-13: The Origin of 'Oumuamua, Our First Interstellar Visitor 05:25: PZ 17 performed more computer simulations to rewind the motion of both Oumuamua and the 3,700 stars within 100 light years of the sun. 06:38: Given how many stars there are, there should be a ton of asteroidal objects floating around in interstellar space.
	2017-12-06: Understanding the Uncertainty Principle with Quantum Fourier Series 13:13: ... kill time during warp journeys by scanning light curves of distant stars for the characteristic dips in brightness due to transiting alien ...
	2017-11-29: Citizen Science + Zero-Point Challenge Answer 01:05: ... sky, spotting things like comets and supernovae or monitoring variable stars. ... 01:52: These exploding stars show up as transient point of light, typically in very distant galaxies. 04:19: ... ninth planet, as well as looking for brown dwarfs-- cool, faint, failed stars-- that live, well, right now in ... 05:15: But there's also Einstein at Home, which searches for LIGO gravitational wave data for signals produced by rotating neutron stars. 05:21: And Milky Way at Home, which generates 3D dynamical models of streams of stars using data from the Sloan Digital Sky Survey.
	2017-11-22: Suicide Space Robots 00:35: But we have few qualms about sending robots on one-way suicide missions to the stars. 09:17: After that, Voyager 1 will meet its very lonely doom, perhaps floating forever in the coldness between the stars.
	2017-10-25: The Missing Mass Mystery 00:18: ... full of hundreds of billions of galaxies, each of them with as many stars. ... 00:33: The shining light of these stars illuminates or is conspicuously absorbed by gas and dust within those galaxies. 01:12: Yet, what if I told you that all of the stars and galaxies and galaxy clusters only comprise 10% of the light sector? 02:38: It's the stuff of stars, planets, gas, dust, you, me. 10:35: As those baryons fall into the dense nexuses of the cosmic web, they'll feed galaxies with material to form new stars. 12:37: TS1336 was expecting last week's episode to be about the discovery of gravitational waves from merging neutron stars. 00:33: The shining light of these stars illuminates or is conspicuously absorbed by gas and dust within those galaxies. 02:38: It's the stuff of stars, planets, gas, dust, you, me.
	2017-10-11: Absolute Cold 09:21: Well, the answer is stars, lots and lots of stars. 09:25: The density of stars in the Milky Way core is around 100 times that of the Milky Way disk. 09:31: ... also expect there to be a good number of stellar remnants, like neutron stars and black holes, that have fallen towards the center from the ... 09:21: Well, the answer is stars, lots and lots of stars.
	2017-10-04: When Quasars Collide STJC 00:08: Red giant stars incinerate planetary systems, but neutron stars cannibalize their red giant neighbors. 00:15: And stellar mass black holes rip neutron stars to shreds. 01:36: Now, we've he talked about the black hole that form in the deaths of massive stars. 01:59: Did they get most of their mass from eating gas and stars from their surrounding galaxy? 07:30: Basically, the black holes slingshot stars outwards through gravitational interactions. 07:51: However, by the time the black holes are only a few light-years apart, there shouldn't be any stars left in between them. 09:54: However, careful observations of the stars in the galaxy can help us figure out the masses of the black holes and look for signs of galaxy mergers. 00:08: Red giant stars incinerate planetary systems, but neutron stars cannibalize their red giant neighbors. 07:51: However, by the time the black holes are only a few light-years apart, there shouldn't be any stars left in between them. 07:30: Basically, the black holes slingshot stars outwards through gravitational interactions.
	2017-09-28: Are the Fundamental Constants Changing? 10:13: The stars themselves would never have formed. 10:16: It might seem lucky that Alpha is fine tuned for a universe with the warmth of stars, and a rich and complex chemistry-- both essential for life. 10:25: ... surprising that 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: ... rocky planets like our Earth-- are extremely common and may orbit most stars in the Milky ... 02:21: This means it's never possible to completely block the star's light. 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. 11:00: ... had detected gravitational waves from the merger of a pair of neutron stars. ... 12:42: ... collapse, when they hit neutron degeneracy pressure, the most massive stars don't manage to stop before the core is smaller than its own event ... 13:14: [INAUDIBLE] wants to confirm that the gold in their ring may have been created in the collision of two neutron stars. 13:25: And if not merging neutron stars, then it was likely a supernova explosion. 12:42: ... collapse, when they hit neutron degeneracy pressure, the most massive stars don't manage to stop before the core is smaller than its own event horizon, ... 02:21: This means it's never possible to completely block the star's light. 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. 02:36: In 2005, Dr. Webster Cash proposed a successor to the coronagraph-- the starshade. 02:50: ... starshade will be up to 50 meters in diameter and hover 80,000 kilometers in front ... 02:59: At that distance, the starshade acts like an artificial eclipse. 03:09: But the starshade goes much further. 03:27: The number and length of pedals optimizes each starshade for a particular wavelength of light. 03:46: The main motivation for building starshades is to suppress the glare of stars enough to see the planets that orbit them. 04:18: With the starshade, we may soon directly observe terrestrial exoplanets with cameras and spectrographs. 04:30: Besides Earth-like exoplanets, the starshade would also be an enormous help in studying quasars and other high-contrast phenomena. 04:39: The first starshade may launch with NASA's WFIRST mission in the 2020s for a budget of around $750 million and a runtime of five years. 05:00: Oh, and one starshade could theoretically serve multiple telescopes. 07:41: ... and even map the cloud structure of a gas giant, especially if you add a starshade to the aragoscope-- because why ... 08:15: So it would be an independent spacecraft, just like the starshade. 09:49: Results probably won't top those of the magnificent starshade and aragoscope, but the orbiting rainbow is cheap. 02:36: In 2005, Dr. Webster Cash proposed a successor to the coronagraph-- the starshade. 02:50: ... starshade will be up to 50 meters in diameter and hover 80,000 kilometers in front ... 02:59: At that distance, the starshade acts like an artificial eclipse. 03:09: But the starshade goes much further. 03:27: The number and length of pedals optimizes each starshade for a particular wavelength of light. 04:18: With the starshade, we may soon directly observe terrestrial exoplanets with cameras and spectrographs. 04:30: Besides Earth-like exoplanets, the starshade would also be an enormous help in studying quasars and other high-contrast phenomena. 04:39: The first starshade may launch with NASA's WFIRST mission in the 2020s for a budget of around $750 million and a runtime of five years. 05:00: Oh, and one starshade could theoretically serve multiple telescopes. 07:41: ... and even map the cloud structure of a gas giant, especially if you add a starshade to the aragoscope-- because why ... 08:15: So it would be an independent spacecraft, just like the starshade. 09:49: Results probably won't top those of the magnificent starshade and aragoscope, but the orbiting rainbow is cheap. 02:59: At that distance, the starshade acts like an artificial eclipse. 03:46: The main motivation for building starshades is to suppress the glare of stars enough to see the planets that orbit them.
	2017-09-13: Neutron Stars Collide in New LIGO Signal? 00:15: ... time spotted gravitational waves from the collision of a pair of neutron stars. ... 01:04: As the data comes in, we're learning a ton about black holes, how they grow, and the stars that produce them. 01:15: LIGO was supposed to also detect some other crazy stuff like certain types of supernova explosion and the merger of binary neutron stars. 01:45: ... about the supposed signal at all, let's refresh our memory on neutron stars. ... 02:00: For the most massive stars, that core will collapse into a black hole. 02:39: ... stars can rotate up to thousands of times per second and have enormous ... 03:01: This was the Hulse-Taylor binary, two neutron stars in orbit around each other, one of which is visible to us as a pulsar. 03:17: And that gravitational radiation sucks energy from the orbiting system, causing the neutron stars to spiral inwards. 03:25: By monitoring the pulses of one of those stars, this inspiral was measured. 03:38: Any neutron stars or black holes in close orbit with each other will eventually collide as they leave gravitational radiation. 03:56: Well, because the universe makes far more neutron stars than black holes. 04:00: See, black holes only form in the deaths of the most massive stars, those over approximately 20 times the Sun's mass. 04:09: But these are also the rarest of stars. 04:12: Neutron stars form from the not quite as rare stars of around 8 to 20 solar masses. 04:18: That means neutron stars should be more common than black holes and neutron star binary systems should merge more often than black whole binaries. 05:37: ... only hit that range in the final second before merger, while neutron stars ring at audible gravitational wave frequencies for at least several ... 07:01: But around 30% of them, the short-lived ones which last for less than 2 seconds, are believed to come from merging neutron stars. 08:03: We rarely see supernovae from this galaxy type because their most massive stars have long since exploded to leave neutron stars and black holes. 09:02: But it turns out that merging neutron stars can do this too. 09:07: As these stars coalesce, most of their material goes into forming a new black hole. 09:12: But the neutron stars' thin iron crust is likely bombarded with neutrons and blasted outwards, spraying a ton of r-process elements into the galaxy. 09:32: Seeing a gravitational wave signal from merging neutron stars would allow us to determine pretty exactly how much mass is lost in the merger. 10:06: But colliding neutron stars are bright across the electromagnetic spectrum. 12:59: Well, the answer is no, thank the stars. 14:10: That method is to watch the effect on the parent stars' light as it passes through the planet's atmosphere. 14:38: ... found by the Doppler method, which can measure the tiny wobble in a star's motion caused by the planet's gravitational ... 09:07: As these stars coalesce, most of their material goes into forming a new black hole. 04:12: Neutron stars form from the not quite as rare stars of around 8 to 20 solar masses. 14:10: That method is to watch the effect on the parent stars' light as it passes through the planet's atmosphere. 14:38: ... found by the Doppler method, which can measure the tiny wobble in a star's motion caused by the planet's gravitational ... 05:37: ... only hit that range in the final second before merger, while neutron stars ring at audible gravitational wave frequencies for at least several ...
	2017-08-30: White Holes 03:49: Now, a real black hole forms from the gravitational collapse of a massive star's core.
	2017-08-24: First Detection of Life 07:42: ... a tiny fraction of the star's light passes through the planet's atmosphere when this happens, but by ... 07:03: Programs like Breakthrough Starshot, as discussed in this video, promise the first close-up observations of a new world in several decades time.
	2017-08-02: Dark Flow 00:26: Planets orbit stars. 00:28: Stars orbit within galaxies.
	2017-07-19: The Real Star Wars 00:33: ... us, science was making incredible bounds, and our sights were set on the stars. ...
	2017-06-21: Anti-Matter and Quantum Relativity 11:53: This is so cool because it shows us how to produce beautiful starscape photographs using some pretty simple camera equipment.
	2017-06-07: Supervoids vs Colliding Universes! 12:10: Last week we talked about the mysterious population three stars, the very first generation of stars that appeared soon after the Big Bang. 12:22: A few of you asked about looking back into the old universe to find population three stars, and that is indeed where we focus our search. 12:41: And we need the largest telescopes in the world to even detect the entire galaxy, let alone any individual stars. 13:04: Right now, efforts are focused on computational modeling of populations of stars to predict the overall light that we expect to come from a galaxy. 13:13: Add population three stars to those models and the light looks very different. 13:17: [INAUDIBLE] et al., 2015, found a galaxy in the old universe whose light is very hard to explain without a lot of pop three stars.
	2017-05-31: The Fate of the First Stars 00:05: Soon after the Big Bang, the first generation of monstrously large stars ignited, lit up the universe, and then died. 00:24: These were the stars of population three. 00:39: In its light, we see telltale signs of the generations of stars that came before it. 00:45: See, the sun and all stars are made of the raw material forged in the heat of the Big Bang itself-- hydrogen and helium, mostly. 01:01: ... elements were forged in the cores of earlier generations of stars-- stars that exploded as supernovae, and spread their element-enriched ... 01:19: Astronomers categorize stars according to the relative quantity of heavy elements that they possess. 01:30: And the relative quantity of metals versus hydrogen and helium is a star's metalicity. 01:36: Stars that formed will recently tend to have the highest metalicities, because they contain the dust of more stellar generations past. 01:45: We divide stars up into three populations. 01:54: Pop one stars formed the most recently, and are still forming today, typically in the disks of spiral galaxies. 02:02: Population two stars are metal pore, with metalicities around 0.1% or even lower. 02:08: These are the oldest stars that we see in the Milky Way. 02:18: Today, they're found in the galactic bulge or in globular clusters, which are ancient, dense islands of stars that orbit far out in the galactic halo. 02:27: Population three stars have no heavier elements whatsoever. 02:32: ... were the first ever stars, shining in the first ever proto galaxies, born of the pristine hydrogen ... 03:08: Except that the longest lived stars-- red dwarfs-- have lifespans of trillions of years. 03:17: Even stars a little smaller than our sun-- the orangish K-type stars-- live for longer than the current age of the universe. 03:31: But stars of the sun's mass and higher that formed over 13 billion years ago, near the beginning of the universe, would now be long gone. 03:53: Before we get to why pop three stars were so large, let's unravel this whole lifespan thing. 03:59: Massive stars live fast, die young, and leave beautiful space-time warping corpses. 04:17: And these stars burned so very, very brightly. 04:20: OK, physics time-- the cores of stars are under extreme pressure due to the gravitational crush of their great mass. 04:34: So the cores of very massive stars are much hotter than our suns-- up to a couple hundred million Kelvin, versus the sun's 15 million K. 05:15: ... the smallest population three stars would have had masses of at least several times that of the sun, while ... 05:26: By comparison, the most massive lighter stars are, at most, a couple of hundred solar masses. 05:33: With masses that high, all population three stars would have gone supernova while the universe was still in its infancy. 05:40: So why do we think the first stars were so massive? 05:44: Well, based on our understanding of how stars formed, they must have been. 05:52: Stars form when vast clouds of mostly molecular hydrogen collapse under their own gravity. 06:12: To collapse into stars, clouds have to cool. 07:17: At that point, the contraction is much slower, and those cloud fragments become stars. 07:44: The result is much larger cloud chunks that evolve into gigantic stars. 07:56: Even generous estimates give these gigantic population three stars only a few million years to live. 08:16: Those first stars changed the face of the universe. 08:20: They produced the first heavy elements that would someday become dust and new stars and planets and-- well-- us. 08:51: These enormous stars are also thought to have left behind enormous black holes when they died. 08:57: In fact, it may be that stars greater than around 250 solar masses can collapse directly into a black hole without exploding. 09:04: ... of giant stars become clusters of giant black holes, which, in turn, would merge into ... 09:34: For purely theoretical objects, population three stars sure were important. 09:47: Now, it may be that there were some smaller pop three stars that still live. 10:07: But the smart money seems to be on pop three stars being long gone. 10:26: It's hard to make sense of this light, unless there are a ton of population three stars in those galaxies. 10:36: The hunt continues for the first stars in the universe. 04:17: And these stars burned so very, very brightly. 08:16: Those first stars changed the face of the universe. 06:12: To collapse into stars, clouds have to cool. 05:52: Stars form when vast clouds of mostly molecular hydrogen collapse under their own gravity. 01:54: Pop one stars formed the most recently, and are still forming today, typically in the disks of spiral galaxies. 05:44: Well, based on our understanding of how stars formed, they must have been. 08:57: In fact, it may be that stars greater than around 250 solar masses can collapse directly into a black hole without exploding. 00:05: Soon after the Big Bang, the first generation of monstrously large stars ignited, lit up the universe, and then died. 03:17: Even stars a little smaller than our sun-- the orangish K-type stars-- live for longer than the current age of the universe. 03:59: Massive stars live fast, die young, and leave beautiful space-time warping corpses. 01:30: And the relative quantity of metals versus hydrogen and helium is a star's metalicity. 03:08: Except that the longest lived stars-- red dwarfs-- have lifespans of trillions of years. 02:32: ... were the first ever stars, shining in the first ever proto galaxies, born of the pristine hydrogen and ... 01:01: ... elements were forged in the cores of earlier generations of stars-- stars that exploded as supernovae, and spread their element-enriched guts ...
	2017-05-17: Martian Evolution 00:06: It's fun to think about humanity settling the galaxy, outposts of familiar Homo sapiens spread among the stars. 13:15: ... measured the very slight offset in the positions of stars around the limb, the edge, of the sun due to the powers of their light ... 13:40: ... need to compare the positions of stars on either side of the sun during the eclipse and then several months ... 13:49: The stars should be a few arcseconds further apart during the eclipse.
	2017-05-10: The Great American Eclipse 00:19: The stars will emerge, and you'll be declared a god. 05:31: They may be an atmospheric effect, perhaps from the same turbulence that makes stars twinkle. 05:40: The stars, by the way, start to come out. 05:31: They may be an atmospheric effect, perhaps from the same turbulence that makes stars twinkle.
	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 ...
	2017-04-05: Telescopes on the Moon 01:40: On the moon, the stars are visible day and night.
	2017-03-15: Time Crystals! 11:27: The answer is that, yeah, it's rare, but there are a lot of stars in the galaxy. 11:41: That's 578 stars out of the 100,000 stars that Kepler monitors.
	2017-03-01: The Treasures of Trappist-1 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. 05:35: Planets further out will receive less light, but the star's infrared intensity provides the heat needed for liquid water. 08:23: But this finding tells us that Earth sized planets are probably common around M dwarf stars. 08:38: ... that M dwarfs are the most numerous stars in the galaxy, we may have seeing a giant boost in the number of ... 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. 05:35: Planets further out will receive less light, but the star's infrared intensity provides the heat needed for liquid water.
	2017-02-22: The Eye of Sauron Reveals a Forming Solar System! 08:34: Stars typically form in groups as very large clouds of molecular hydrogen collapse and break apart into separate pieces. 08:41: The stars don't always stay in the same groups. 09:17: We're going to need more observations to figure out whether Fomalhaut is typical of stars in their youth, or is actually truly unusual. 08:41: The stars don't always stay in the same groups. 08:34: Stars typically form in groups as very large clouds of molecular hydrogen collapse and break apart into separate pieces.
	2017-02-15: Telescopes of Tomorrow 01:50: So planets form around young stars. 01:52: And young stars lie tucked away in blankets of gas and dust. 02:23: This will provide another set of baby pictures, the formation of the very first stars and galaxies in our universe. 02:55: Webb will help us learn whether stars form galaxies or galaxies form stars and the role of dark matter in the whole process. 06:02: To our eyes, this is what causes stars to twinkle. 06:53: ... the upper atmosphere, where their light will produce artificial guide stars. ... 07:05: ... mirrors will deform up to hundreds of times per second to keep the guide stars, along with everything else in the telescope's sights, in sharp ... 07:36: It's hoped that GMT will even find traces of the very first population of stars that formed in our universe. 08:44: We'll be able to track the motion of rogue high-velocity stars whizzing through our galaxy. 08:58: It will be easier to find new supernovae, the explosive deaths of stars which, among other things, will improve our understanding of dark energy. 02:55: Webb will help us learn whether stars form galaxies or galaxies form stars and the role of dark matter in the whole process. 01:52: And young stars lie tucked away in blankets of gas and dust. 08:44: We'll be able to track the motion of rogue high-velocity stars whizzing through our galaxy.
	2017-02-02: The Geometry of Causality 14:09: Stars are so good at fusion, in part, because they're the cause of creating high densities. 14:54: ... been left over by the deaths of an insanely large first generation of stars, perhaps thousands of times the mass of the ...
	2017-01-25: Why Quasars are so Awesome 00:29: Take stars-- 100 billion megaton per second thermonuclear explosions that just don't stop exploding. 00:42: Giant molecular clouds-- beautiful and tranquil, but also screaming vortices spitting stars into the cosmos. 03:37: ... hysterical flurry of hypothesizing followed-- swarms of neutron stars, an alien civilization harnessing their entire galaxy's power, bright, ... 07:36: As galaxies coalesced, they went through starburst phases, producing new stars at insane rates. 07:43: The birth of large numbers of new stars is always quickly followed by the explosive deaths of the most massive, shortest lived of those stars. 08:46: Hot gas doesn't collapse into stars, and so the extreme starburst activity was shut down. 00:29: Take stars-- 100 billion megaton per second thermonuclear explosions that just don't stop exploding.
	2017-01-19: The Phantom Singularity 17:45: You are starstuff.
	2017-01-11: The EM Drive: Fact or Fantasy? 12:46: There are even plans to use lasers to communicate between the hopefully upcoming Starshot Shot light sail mission to Alpha Centauri.
	2017-01-04: How to See Black Holes + Kugelblitz Challenge Answer 02:14: But more compellingly, we've tracked the motion of stars near the galactic core for many years. 03:55: Interferometry is going to be used to study much smaller black holes in our galaxy, the remnants of dead stars. 04:02: These black holes occasionally pass in front of more distant background stars, gravitationally lensing the star's light. 06:59: ... only part of this doomed triangle above the collapsing star's surface actually has the crazy spacetime behavior of the interior of a ... 04:02: These black holes occasionally pass in front of more distant background stars, gravitationally lensing the star's light. 06:59: ... only part of this doomed triangle above the collapsing star's surface actually has the crazy spacetime behavior of the interior of a black ...
	2016-12-21: Have They Seen Us? 02:31: ... SETI, in earnest since the '60s, when Frank Drake first peeked at the stars Tau Ceti and Epsilon ... 04:11: Our best-targeted search so far, the SETI Institute's Project Phoenix, scanned 800 stars within 200 light years. 12:11: However, our steady broadcasts have only washed over a few hundred solar-type star systems and only a few thousand stars total. 02:31: ... SETI, in earnest since the '60s, when Frank Drake first peeked at the stars Tau Ceti and Epsilon ... 12:11: However, our steady broadcasts have only washed over a few hundred solar-type star systems and only a few thousand stars total.
	2016-12-14: Escape The Kugelblitz Challenge 01:35: A black hole forms when the core of a very massive star collapses under its own gravity at the end of a star's life. 02:11: If the star's core collapses to a size smaller than its own Schwarchild radius, then the event horizon forms, engulfing what's left of the star. 01:35: A black hole forms when the core of a very massive star collapses under its own gravity at the end of a star's life.
	2016-11-30: Pilot Wave Theory and Quantum Realism 12:49: In our last episode, we talked about the strangest of stars, the strange star-- aptly named. 14:25: Sebastian Lopez asks how are the magnetic fields of neutron stars created. 15:06: With their extreme rotation rates, neutron stars support electric currents sufficient for magnetic fields of up to 100 million tesla. 14:25: Sebastian Lopez asks how are the magnetic fields of neutron stars created. 15:06: With their extreme rotation rates, neutron stars support electric currents sufficient for magnetic fields of up to 100 million tesla.
	2016-11-16: Strange Stars 00:00: ... PLAYING] As if black holes and neutron stars aren't weird enough, physicists have very good reason to believe that ... 00:44: The most wonderfully monstrous of these are the remnant corpses of the most massive stars, stellar zombies like neutron stars and black holes. 01:29: Literally, I'm talking about strange stars. 01:32: Before we can understand strange stars, we need to start with a stellar remnant that we know for sure exists, the neutron star. 02:36: Our understanding of neutron stars seems to fit the behavior of pulsars very well, at least for most of them. 02:43: But for some, we see hints of weird things happening deep beneath the star's surface, which we'll get to. 02:49: ... ordinary neutron stars, that surface is a thin crust of iron, which quickly gives way to a fluid ... 03:42: And we certainly can't test what happens to it when subjected to the insane pressures at a neutron star's core. 06:18: We call these strange stars. 06:51: It could be that neutron stars have an electroweak core, an apple-sized ball with the mass of two Earths in which quarks themselves burn. 07:08: And those may provide the final pressure that halts the collapse of some stars into a black hole, at least for another million years or so. 08:44: There are other candidates that could be quark and/or strange stars. 09:28: Nothing is confirmed yet, but there are tantalizing hints that these exotic stars, these monsters in the math, may be very real. 03:42: And we certainly can't test what happens to it when subjected to the insane pressures at a neutron star's core. 00:44: The most wonderfully monstrous of these are the remnant corpses of the most massive stars, stellar zombies like neutron stars and black holes. 02:43: But for some, we see hints of weird things happening deep beneath the star's surface, which we'll get to.
	2016-11-09: Did Dark Energy Just Disappear? 00:37: These exploding white dwarf stars have predictable brightnesses that allow astronomers to figure out how far away they are. 06:35: ... effect of regular energy, and that's mostly dark matter, but also stars, planets, gas, radiation, et ... 12:44: So Keivan Stassun's course, "The Life and Death of Stars," gave me some great insights into the nature of the weird corpses left after stars die. 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 04:42: It tells us the number of stars of each given type within a certain distance. 04:46: For 100 light years, we have 512 G-Type stars: that's the same type as our sun. 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. 07:10: There are 100,000 stars in the Kepler Sample. 07:13: The Kepler Observatory points only in one direction, so those stars are spread along a column a few thousand light years long. 07:21: ... ask, "How large a sphere centered on the sun would also contain 100,000 stars?" There should be, on average, around one Dyson Swarm in those 100,000 ... 07:36: Again, using the "solstation" website, we get that there are around 5,000 stars total per 100 light year radius sphere. 07:46: So you'd get 100,000 stars in a 270 light year sphere. 08:01: Now we've studied all the non-red dwarf stars in that volume pretty thoroughly, and none of them show any signs of having Dyson Swarms. 07:36: Again, using the "solstation" website, we get that there are around 5,000 stars total per 100 light year radius sphere.
	2016-10-19: The First Humans on Mars 09:52: A star's core needs to be more massive than around three times the mass of the sun in order to collapse into a black hole. 10:01: However primordial black holes don't form from stars and so aren't subject to this restriction. 10:09: ... tell us that it was impossible for them to have been produced by massive stars, which are rare, as far as stars ... 09:52: A star's core needs to be more massive than around three times the mass of the sun in order to collapse into a black hole.
	2016-10-12: Black Holes from the Dawn of Time 00:49: That's in the core of the most massive stars when they die. 05:27: In stars in our galaxy, in distant quasars, even in gamma ray bursts. 05:53: The smallest should fall into neutron stars, causing them to either explode or become black holes themselves. 06:01: But we see loosely bound binaries, and normal star clusters, and plenty of neutron stars. 05:53: The smallest should fall into neutron stars, causing them to either explode or become black holes themselves.
	2016-10-05: Are We Alone? Galactic Civilization Challenge 00:19: ... biological, and sociological factors, each of which narrows the range of stars in our galaxy that may have produced a surviving ... 02:43: Around 11 billion of those are Earth-like planets around Sun-like stars.
	2016-09-14: Self-Replicating Robots and Galactic Domination 00:33: Stars for the most part act very star-like, their brightnesses and colors slavishly following the equations of stellar physics.
	2016-08-24: Should We Build a Dyson Sphere? 00:11: ... mega structures, capable of harvesting the power output of entire stars, the as yet inexplicable Kepler Space Telescope observation of swarms of ... 01:16: On the other hand, securing access to an entire star's energy output officially elevates a civilization to type 2 on the Kardashev scale. 06:23: Would other civilizations have gone that route, casting very conspicuous shadows on their home stars for us to detect? 01:16: On the other hand, securing access to an entire star's energy output officially elevates a civilization to type 2 on the Kardashev scale. 07:33: We talked about one example, the Kugelblitz, in our previous episode on possible starship engines.
	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.
	2016-08-03: Can We Survive the Destruction of the Earth? ft. Neal Stephenson 01:30: ... overturning the biosphere's equilibrium, or even nearby exploding stars. ... 08:47: Fortunately, we know for sure that there are no stars ready to go supernova within any dangerous distance.
	2016-07-27: The Quantum Experiment that Broke Reality 11:18: ... Blank asks, "Wasn't Jupiter almost a star?" Well, the lowest mass stars are around 7.5% the mass of the Sun, while Jupiter is 1/10,000 of a ... 11:45: Well, the Sun and other stars don't need rocky cores because they are massive enough for all of that gas to collapse by itself.
	2016-07-20: The Future of Gravitational Waves 04:54: We should eventually see mergers between two neutron stars or a neutron star and a black hole, as well as supernova explosions.
	2016-06-22: Planck's Constant and The Origin of Quantum Mechanics 10:38: ... the Planck constant can be read in the color of the sun and the stars, in the brightness of the different colors of the ...
	2016-06-15: The Strange Universe of Gravitational Lensing 02:11: ... of the sun and to measure the tiny change in the position of nearby stars due to the deflection of their light by the sun's gravitational ... 02:26: The stars had shifted. 03:03: For stars, this effect is typically small. 06:13: ... galaxy brightens and dims due to the gravitational fields of individual stars in that lens in a process called ... 06:25: As those stars sweep in front of the quasars in a vortex, its different parts change in magnification to different degrees and at different times. 07:20: ... stellar bodies-- black holes, neutron stars, and brown dwarves-- occasionally pass in front of other starts and lens ... 09:19: The stars are mostly where you see them-- mostly. 06:25: As those stars sweep in front of the quasars in a vortex, its different parts change in magnification to different degrees and at different times.
	2016-06-01: Is Quantum Tunneling Faster than Light? 05:01: In fact, without quantum tunneling, stars could not fuse hydrogen into heavy nuclei.
	2016-05-18: Anti-gravity and the True Nature of Dark Energy 11:55: In a recent episode, we talked about the Breakthrough Starshot program, LightSail to the stars. 13:43: Aging Reversed would like to spend the entire Starshot budget to cure cancer, rather than sending a speck of dust into nothing. 13:51: Well, the final cost of Starshot is expected to be several billion. 14:12: ... to underestimate the benefits of inspiring forward-looking projects like Starshot. ... 13:43: Aging Reversed would like to spend the entire Starshot budget to cure cancer, rather than sending a speck of dust into nothing. 11:55: In a recent episode, we talked about the Breakthrough Starshot program, LightSail to the stars.
	2016-05-04: Will Starshot's Insterstellar Journey Succeed? 01:18: Looks like light sails will be the first propulsion tick to get an unmanned probe to the stars. 10:06: The universe expands exponentially forever and eventually the stars die out, the black holes evaporate, and the universe undergoes heat death. 11:33: ... example, we can use cepheid variable stars, another type of standard candle, to get an independent distance to the ... 10:06: The universe expands exponentially forever and eventually the stars die out, the black holes evaporate, and the universe undergoes heat death. 00:02: Breakthrough Starshot plans to send spacecraft to the nearest star within your lifetime. 00:42: Billionaire physicist Yuri Milner recently announced the Breakthrough Starshot program. 03:29: In a way, Starshot is an update to the Starwisp. 03:38: The main innovation of the Starshot is that it's not just low mass, it is ultra low mass, weighing in at grams rather than Starwisp's kilograms. 03:51: ... Starshot will be comprised of a sail around a meter in diameter that's made of an ... 04:24: Another big difference compared to Starwisp is that Starshot will be powered by a visible light laser, not a maser. 05:06: This thing could burn Yuri Milner's tag on the surface of the moon and also accelerate a Starshot craft to 20% of the speed of light in a few minutes. 05:45: What can a Starshot probe expect to do in those few minutes? 06:40: ... at the other end, Starshot probes need to know where to point the cameras and then beam that info ... 08:26: And what will the Starshot probe find when it reaches Alpha Cen? 05:06: This thing could burn Yuri Milner's tag on the surface of the moon and also accelerate a Starshot craft to 20% of the speed of light in a few minutes. 00:02: Breakthrough Starshot plans to send spacecraft to the nearest star within your lifetime. 05:45: What can a Starshot probe expect to do in those few minutes? 08:26: And what will the Starshot probe find when it reaches Alpha Cen? 05:45: What can a Starshot probe expect to do in those few minutes? 06:40: ... at the other end, Starshot probes need to know where to point the cameras and then beam that info back to ... 00:42: Billionaire physicist Yuri Milner recently announced the Breakthrough Starshot program.
	2016-04-27: What Does Dark Energy Really Do? 04:18: OK, so here's the experiment-- watch stars explode across the cosmos.
	2016-04-13: Will the Universe Expand Forever? 10:06: ... this main sequence of elements produced in the cause of dying high-mass stars and asks how elements out of this sequence get ... 10:20: In fact, there are many different fusion reactions occurring in the cores of those dying high-mass stars. 11:06: As for fluorine, that's actually one of the more confusing ones, because it's not produced efficiently in any known reaction in high-mass stars. 11:15: But recent work has suggested that it might actually be formed in lower-mass stars like our sun after they enter the red giant phase. 11:54: However, stars don't all orbit at exactly the same rate. 11:58: Orbits aren't perfectly circular, and stars drift apart as they move in and out of the spiral arms and above and below the galactic disc. 12:21: It collapsed into the Sun's sibling stars, which are also scattered across the galaxy by now. 12:28: And it was blasted away by supernovae from the most massive stars it produced. 12:35: ... be from those supernovae, but more will be from previous generations of stars that enriched that giant cloud before it formed stars of its ... 12:57: Be noble, for you are made of stars." [THEME MUSIC] 11:54: However, stars don't all orbit at exactly the same rate. 11:58: Orbits aren't perfectly circular, and stars drift apart as they move in and out of the spiral arms and above and below the galactic disc.
	2016-04-06: We Are Star Stuff 04:31: And all of that hydrogen and helium would later become the fuel for the later formation of stars. 04:37: And stars are important. 04:40: As well as providing us with all of their glorious entropy-resisting energy, stars are element factories, stellar alchemists. 04:48: While the early universe had around 20 minutes to forge its nuclei, stars have millions to billions of years. 05:36: ... the largest stars, any bigger than around eight times the sun's mass, reach the ends of ... 07:38: In this explosion, all those elements are spread into interstellar space, providing fuel for later stars to form. 09:16: ... were formed not in a supernova, but in the collision of two neutron stars. ... 09:27: ... two very massive stars in binary orbit leave behind neutron star corpses, those remnants will ... 05:36: ... giants, and their cores become hot enough to continue where smaller stars leave ... 00:00: ... PLAYING] Carl Sagan said that we are "starstuff." Most of the atoms in our body were forged in violent stellar alchemy and ... 10:13: We are "starstuff." But more, we our universe stuff, the most complex component that has risen from a beautiful and chaotic spacetime.
	2016-03-30: Pulsar Starquakes Make Fast Radio Bursts? + Challenge Winners! 01:11: ... cataclysmic events, like colliding stellar remnants, supernovae, neutron stars collapsing into black holes, crazy stuff like ... 01:56: ... the best contenders involve young neutron stars, which rotate at insane rates and occasionally give off extremely intense ... 01:11: ... cataclysmic events, like colliding stellar remnants, supernovae, neutron stars collapsing into black holes, crazy stuff like ...
	2016-03-23: How Cosmic Inflation Flattened the Universe 11:04: This is also true of the stars in a eliptical galaxies. 11:08: Stars a small enough, compared to the distances between them, that they can be in these random orbits. 11:14: The reason spiral galaxies are discy is that those discs formed before the stars actually formed, back when the material was mostly gas.
	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 dimensions ... 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. 07:08: A very similar balance applies to stars. 07:18: And this hydrostatic equilibrium keeps stars like our sun extremely spherical and happily burning away for billions of years. 08:29: These things are even more massive than single planets or stars. 00:23: It loves building spheres like stars, planets, and moons, and disks like spiral galaxies, solar systems, and some crazy stuff like quasars. 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.
	2016-02-24: Why the Big Bang Definitely Happened 12:11: I'll still appreciate the impractical beauty after those insights allow me to ride my inflaton-powered anti-gravity warp ship to the stars.
	2016-02-11: LIGO's First Detection of Gravitational Waves! 02:06: Now, LIGO is sensitive to pairs of stellar mass black holes and/or neutron stars. 02:18: Now these stellar remnants are sometimes found in pairs, typically when the original stars were also a binary pair in orbit around each other. 02:40: Now we've seen this slow orbital decay in binary neutron stars. 03:22: ... those few minutes, the merging black holes or neutron stars produce such strong ripples in the fabric of spacetime that LIGO can see ... 04:07: In the case of merging neutron stars, it's a much smaller distance, and so none have been seen yet, although it will happen eventually. 04:14: We'll also spot supernova explosions that produce neutron stars. 06:13: ... waves at frequencies produced by merging black holes and neutron stars, as well as the formation of neutron stars and supernova ... 06:24: And potentially, even the actual spin of neutron stars. 06:48: ... see the slow ringing of binary white dwarf stars in our own galaxy, as well as the final dance of pairs of truly ... 03:22: ... those few minutes, the merging black holes or neutron stars produce such strong ripples in the fabric of spacetime that LIGO can see them ...
	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.
	2015-12-16: The Higgs Mechanism Explained 09:05: ... stars near the core of a galaxy with merging super massive black holes should ...
	2015-12-09: How to Build a Black Hole 01:27: The details of the deaths of massive stars are pretty awesome. 01:33: ... the last throes of a very massive star's life, increasingly frantic fusion in the interior produces one periodic ... 07:41: The space time curvature at the neutron star's surface is pretty extreme. 07:58: And yet, below the star's surface, their lurks the potential event horizon, the surface of infinite time dilation. 01:33: ... the last throes of a very massive star's life, increasingly frantic fusion in the interior produces one periodic table ... 07:41: The space time curvature at the neutron star's surface is pretty extreme. 07:58: And yet, below the star's surface, their lurks the potential event horizon, the surface of infinite time dilation.
	2015-11-18: 5 Ways to Stop a Killer Asteroid 01:38: These are the shooting stars that you see on a dark night. 10:47: Stars are very far apart.
	2015-11-05: Why Haven't We Found Alien Life? 00:26: ... and probably billions of them are Earth-sized planets around sun-like stars. ... 01:17: Surely, some civilizations must make it through these growing pains and manage to reach the stars. 09:33: ... all of the sun-like stars and Earth-like planets that will ever form over the full past and future ... 01:13: As we saw in a previous episode, we're not so far from building starships ourselves.
	2015-10-28: Is The Alcubierre Warp Drive Possible? 06:44: As I've argued before, we'll reach the stars by sub light speed starships long before that. 09:06: Those dips are the drops in the star's brightness from some stuff moving in front of the star. 00:07: So when do we get our first starship? 02:49: A starship inside the bubble is carried along for the ride while feeling no acceleration at all. 06:44: As I've argued before, we'll reach the stars by sub light speed starships long before that. 02:49: A starship inside the bubble is carried along for the ride while feeling no acceleration at all. 06:44: As I've argued before, we'll reach the stars by sub light speed starships long before that.
	2015-10-22: Have Gravitational Waves Been Discovered?!? 03:16: ... most insane gravitational phenomena in the universe-- neutron stars or black holes in-spiraling just before merger, or gravitational ... 04:34: This has been seen in binary neutron stars. 04:42: ... could actually see g-waves, we'd be able to study black holes, neutron stars, even the extremely early universe in ways never before ... 06:51: LIGO really just scratched the minimum sensitivity needed to spot merging neutron stars and black holes in relatively nearby galaxies.
	2015-10-15: 5 REAL Possibilities for Interstellar Travel 00:03: The future of humanity is in the stars. 00:48: Humanity's first adventure to the stars won't and shouldn't wait for far-off fantastical technologies. 05:13: We've only been able to do this with small numbers of antiprotons at a time, not the kilograms we'd need to get to the stars. 06:07: What if we could sail to the stars on a wind made of light, the light sail? 09:14: OK, so lots of ways to get to the stars. 10:34: Humanity's first attempts to land on other worlds might well have us sailing to the stars. 00:10: So what would it take to build a starship? 00:54: Our first starship would use technologies achievable in our lifetimes. 01:01: Now building a starship is going to take a huge amount of political cooperation, money, and single-minded focus. 01:31: The key is finding the right balance between speed of the starship and the amount of time it would take us to develop the tech to build it. 03:04: In fact why not choose the most middle option and just explode nukes behind our starship and surf the blasts. 03:16: ... assume modern thermonuclear devices and launch with roughly 3/4 of our starship's mass being taken up by 300,000 1 megaton hydrogen bombs, blast them ... 08:11: The smaller the black hole, the more radiation, and this radiation could drive our starship. 09:50: Pure antimatter and the Kugelblitz drives, they're the starships of the far future. 03:16: ... assume modern thermonuclear devices and launch with roughly 3/4 of our starship's mass being taken up by 300,000 1 megaton hydrogen bombs, blast them ... 09:50: Pure antimatter and the Kugelblitz drives, they're the starships of the far future. 03:16: ... assume modern thermonuclear devices and launch with roughly 3/4 of our starship's mass being taken up by 300,000 1 megaton hydrogen bombs, blast them behind us ...
	2015-10-07: The Speed of Light is NOT About Light 12:00: And all stars besides red dwarves would be long dead.
	2015-09-30: What Happens At The Edge Of The Universe? 04:22: But for now, let's just assume we have a nice Alcubierre-class warp-ship and we burn the mass energy of entire stars to chase the particle horizon. 05:12: It's lumpy on small scales due to stars and galaxies, but smooth on large, sort of like ripples on the ocean. 08:25: Shadowmax889 asks why stars and planets aren't filled with dark matter? 08:57: But then these clouds radiate light in different ways, allowing the gas to cool even more and collapse into stars. 08:42: To collapse completely into a star-sized object, it would have to lose a lot more energy.
	2015-09-23: Does Dark Matter BREAK Physics? 00:18: The Milky Way galaxy is spinning so fast that it should be scattering its stars into the void. 00:24: ... we can see, we can only account for 10% of the mass needed to hold its stars in ... 01:22: But again, we find the clusters appear to have way more mass than we see in the stars alone, that is if we understand gravity. 02:19: ... the galaxy would need to be swarming with baryonic things as massive as stars, but that are so compacted that they're basically ... 02:37: And they're basically crunched down, compact, dead or failed stars, black holes, neutron stars, brown dwarfs, Macaulay Culkin, et cetera. 03:23: Well, the problem is that the stars on the edge of the galaxy are moving just as fast as the stars near the center. 04:03: The stars alone give you plenty of gravity. 04:54: The gas was ripped away from the stars and now lives between the clusters. 05:08: ... be, then that dark matter should pass right on through, just like the stars. ... 05:25: And we see that in the Bullet Cluster, the dark matter is with the stars. 02:37: And they're basically crunched down, compact, dead or failed stars, black holes, neutron stars, brown dwarfs, Macaulay Culkin, et cetera.
	2015-06-17: How to Signal Aliens 03:28: ... like NASA's Kepler satellite, astronomers stare at 150,000 or so stars at once continually for a few years, looking for the tiny dips in ... 04:00: With a few Kerbal Keplers, the Kerbal astronomers could look at hundreds of thousands or millions of stars at once. 05:55: ... SETI also be looking for geometric alien billboards orbiting nearby stars. ...
	2015-06-03: Is Gravity An Illusion? 10:42: Earth analogs in Earth-like orbits around Sun-like stars are not going to be visible. 11:08: ... of how planetary systems form, of how proximity to different kinds of stars affects the atmospheres of planets, and so forth-- the prospect for ...
	2015-05-27: Habitable Exoplanets Debunked! 03:46: You can measure the atmosphere of an exoplanet, but not if that exoplanet is an Earth-sized rocky body in a star's habitable zone. 04:23: ... directly image the planet, improving the contrast by blocking out the star's light, kind of like putting your hand over your eyes on a sunny day to ... 04:39: The planet just gets washed out by the star's light. 05:01: ... this method only works for planets that are really close to their stars, because only planets that are close in will get hot enough to glow ... 05:34: ... of Earth-sized planets in Earth-like orbits around Sun-like like stars. ... 03:46: You can measure the atmosphere of an exoplanet, but not if that exoplanet is an Earth-sized rocky body in a star's habitable zone. 04:23: ... directly image the planet, improving the contrast by blocking out the star's light, kind of like putting your hand over your eyes on a sunny day to help see ... 04:39: The planet just gets washed out by the star's light. 04:23: ... directly image the planet, improving the contrast by blocking out the star's light, kind of like putting your hand over your eyes on a sunny day to help see your ...
	2015-04-29: What's the Most Realistic Artificial Gravity in Sci-Fi? 00:10: [MUSIC PLAYING] Whether you realize it or not, artificial gravity is essential to most sci-fi stars. 01:06: You'd need either enormous amounts of mass, so much that you'd basically have a planet and not a starship. 01:32: I'm thinking of something called the Gravitron, maybe the Starship 3,000.
	2015-04-01: Is the Moon in Majora’s Mask a Black Hole? 04:57: The only solid macroscopic objects in nature that are that dense are neutron stars. 07:43: ... Smart" where Joe Hanson explained that the average color of all visible stars in the universe comes out to an off-white called Cosmic ... 08:01: Oxygen gets fused in the cores of stars. 08:03: And as far as I know, the first stars didn't start forming until a couple hundred million years or so after the sky went dark.
	2015-03-25: Cosmic Microwave Background Explained 00:12: Stars and galaxies notwithstanding, space is pitch black. 03:06: At this temperature, it's too hot for electrons and protons to even coalesce into atoms, let alone stars, planets or galaxies. 05:03: Well, they managed to clump, become stars, galaxies, and through a complicated process of cosmic recycling, us. 03:06: At this temperature, it's too hot for electrons and protons to even coalesce into atoms, let alone stars, planets or galaxies.
	2015-02-18: Is It Irrational to Believe in Aliens? 00:40: Well, the Milky Way galaxy has about 200 billion stars. 00:54: So 200 billion stars, 200 billion habitable planets.
	2015-02-11: What Planet Is Super Mario World? 05:08: In fact, g values this large would more likely occur on stars.

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