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	2022-12-08: How Are Quasiparticles Different From Particles? 15:32: ... Exoplanets," “Planet Hunting with the James Webb Telescope, or “Killer Asteroid: Defending Earth,” which looks at how new space missions are being ...
	2022-01-12: How To Simulate The Universe With DFT 14:53: We told you that an asteroid-mass, atom-sized black hole would pass straight through the earth if it impacted.
	2021-12-20: What Happens If A Black Hole Hits Earth? 03:25: ... contentious window of possible masses, comparable to the masses of large asteroids. Black holes this big don’t devour stars like Cygnus X-1, and they don’t ... 04:01: ... thousands, of them to be in the solar system right now. And, just like asteroids, given enough time some of them will quite literally cross paths with the ... 05:13: ... hole has the mass of the Martian moon phobos - 10^16 kg like a large asteroid. That gives it an event horizon the size of a hydrogen atom. At ... 08:16: ... These days standard narrative is that the Tunguska resulted from an asteroid or comet exploding in the ... 10:44: ... the shape of a black hole’s crater would be different from that of an asteroid. ... 11:02: ... an asteroid hits the moon, it stops very quickly, making something of a big round ... 12:01: ... of quartz and pyrite that otherwise couldn’t be produced by regular asteroid impacts, and a line of that fancy quartz should point from one crater to ... 11:02: ... an asteroid hits the moon, it stops very quickly, making something of a big round ... 12:01: ... of quartz and pyrite that otherwise couldn’t be produced by regular asteroid impacts, and a line of that fancy quartz should point from one crater to the ... 03:25: ... less fortunate for everyone else - if dark matter really is made of asteroid-mass black holes then there must be an absolutely insane number of them out ... 04:26: ... question. So let’s figure it out. First to allay your concerns - if an asteroid-mass primordial black hole hit the Earth we wouldn’t be destroyed - which is ... 07:05: ... for matter trying to flow in. Its Eddington limit is very low. For an asteroid-mass black hole at the absolute top end of our mass range, the cloud of ... 03:25: ... less fortunate for everyone else - if dark matter really is made of asteroid-mass black holes then there must be an absolutely insane number of them out there ... 07:05: ... for matter trying to flow in. Its Eddington limit is very low. For an asteroid-mass black hole at the absolute top end of our mass range, the cloud of plasma is ... 03:25: ... less fortunate for everyone else - if dark matter really is made of asteroid-mass black holes then there must be an absolutely insane number of them out there to ... 04:26: ... question. So let’s figure it out. First to allay your concerns - if an asteroid-mass primordial black hole hit the Earth we wouldn’t be destroyed - which is good, ... 03:25: ... contentious window of possible masses, comparable to the masses of large asteroids. Black holes this big don’t devour stars like Cygnus X-1, and they don’t ... 04:01: ... thousands, of them to be in the solar system right now. And, just like asteroids, given enough time some of them will quite literally cross paths with the ... 03:25: ... contentious window of possible masses, comparable to the masses of large asteroids. Black holes this big don’t devour stars like Cygnus X-1, and they don’t warp ...
	2021-04-13: What If Dark Matter Is Just Black Holes? 06:20: ... matter to be made of black holes with masses around that of a larger asteroid or small moon, we’d need truly ridiculous numbers of them to get all the ...
	2020-12-08: Why Do You Remember The Past But Not The Future? 02:16: Actually I’m an astrophysicist, so we’ll think of the brain as a very small asteroid. 02:37: So what does an asteroid remember? 03:10: Any good geologist could read the asteroid’s memory and deduce a rough formation history. 03:15: ... the exact positions and velocities of every particle comprising the asteroid and calculate their paths backwards to recover its exact formation ... 03:59: NONE of that appears to be recorded in the asteroid of the present day. 04:02: ... fast forward many, many times the current age of the universe and the asteroid will decay into a mist of subatomic ... 06:02: ... “Feynman diagram” of our asteroid looks like countless particles coming together in many different ways - ... 06:28: The time-reversed view of the asteroid looks nothing like the time-forward view. 06:34: ... asteroid just assembles from subatomic particles with all of its detailed ... 07:04: The reverse time direction seems unnatural, but what’s different in terms of the asteroid’s record, or memory of its formation? 07:14: Let’s look at the asteroid after its very last interaction with the outside universe. 07:50: But in the case of the asteroid, time symmetry is much more easily broken. 07:56: Just rewind the clock to the moment before the asteroid’s very last interaction with the outside universe. 08:06: ... predict that future cosmic ray strike with the internal structure of the asteroid ... 08:18: Before the cosmic ray strikes, the asteroid has no knowledge of the incoming impact. 08:36: ... the time-reversed case we have an asteroid formed from an incredibly improbable coalescence of particles - but the ... 08:56: That means that before the cosmic ray hit, the asteroid was correlated with its environment. 09:14: ... then the asteroid will loses those correlations one by one. This reversed time scenario ... 10:17: ... is increasing universe-wide, but the smallest chunks of the universe - asteroids, brains for example - also tend to build correlations with their ... 08:36: ... the time-reversed case we have an asteroid formed from an incredibly improbable coalescence of particles - but the most ... 02:37: So what does an asteroid remember? 07:50: But in the case of the asteroid, time symmetry is much more easily broken. 03:10: Any good geologist could read the asteroid’s memory and deduce a rough formation history. 07:04: The reverse time direction seems unnatural, but what’s different in terms of the asteroid’s record, or memory of its formation? 07:56: Just rewind the clock to the moment before the asteroid’s very last interaction with the outside universe. 10:17: ... is increasing universe-wide, but the smallest chunks of the universe - asteroids, brains for example - also tend to build correlations with their ... 03:10: Any good geologist could read the asteroid’s memory and deduce a rough formation history. 07:04: The reverse time direction seems unnatural, but what’s different in terms of the asteroid’s record, or memory of its formation?
	2020-06-15: What Happens After the Universe Ends? 17:44: ... Stark realizes we can have an asteroid impact and alien virus wrapped up in one convenient single apocalypse, ...
	2020-06-08: Can Viruses Travel Between Planets? 08:06: Viruses can also be launched into space embedded in rocks that are ejected in asteroid or comet impacts.
	2019-12-09: The Doomsday Argument 15:47: Now the non-brain-breaking analogy is a 2-torus like in the game Asteroids, or PacMan where opposite walls connect to each other.
	2019-11-04: Why We Might Be Alone in the Universe 09:48: It no doubt sucked up many comets and asteroids would otherwise have hit the Earth. 11:08: ... development - what if the Cambrian explosion had never happened, or the asteroid never wiped out the dinosaurs, or an extra asteroid wiped out our ... 09:48: It no doubt sucked up many comets and asteroids would otherwise have hit the Earth.
	2019-09-23: Is Pluto a Planet? 04:01: So the class of asteroids came into being. 04:18: How many asteroids should we then classify as planets? 07:34: Pluto became to the Kuiper belt what Ceres was to the asteroid belt. 15:56: ... than a planet and so presumably easier to protect from radiation and asteroids than the entire surface of ... 07:34: Pluto became to the Kuiper belt what Ceres was to the asteroid belt. 04:01: So the class of asteroids came into being. 04:18: How many asteroids should we then classify as planets? 15:56: ... than a planet and so presumably easier to protect from radiation and asteroids than the entire surface of ...
	2019-09-03: Is Earth's Magnetic Field Reversing? 09:41: ... could be an asteroid or comet impact, an interaction between the core and mantle – for ...
	2019-08-12: Exploring Arecibo in VR 180 01:02: ... is also a space radar that can bounce rate of pulses off planets and asteroids as far as Jupiter Or send messages to the stars. Let's check out the ...
	2018-12-12: Quantum Physics in a Mirror Universe 00:02: ... better numbers than randomly scattering with the philic bacteria from asteroid impacts with a non technological planet even if non-tech planets are ...
	2018-12-06: Did Life on Earth Come from Space? 00:37: ... that debris from planetary surfaces can be ejected into space during asteroid or comet impacts hundreds of meteorites have been found on earth that ...
	2018-11-21: 'Oumuamua Is Not Aliens 00:41: Nothing unusual about such asteroids and comets. 02:17: The geometry is very unusual for an asteroid or comet. 02:05: ... produce a cometary tail, so it was assumed it must be more rocky or asteroid-like, at least on the ... 00:41: Nothing unusual about such asteroids and comets.
	2018-08-23: How Will the Universe End? 09:35: But smaller stellar remnants, ancient planets, asteroids, et cetera, could persist.
	2018-07-04: Will A New Neutrino Change The Standard Model? 11:01: In the last two episodes we covered the black-hole-information paradox and asteroid mining. 12:14: A few of you wonder whether adding extra mass to Earth from asteroid mining could lead to problems like with our orbit or Earth's gravitational pull. 12:22: So Earth is around 2,000 times more massive than the entire asteroid belt. 12:38: Some of you also wondered whether mining the Moon could be more efficient than mining the asteroid belt. 12:43: Well, the moon is definitely an option for mining, and it's going to have some useful heavy elements from crashed asteroids. 12:49: It's not clear that it's better than near-earth asteroids. 12:53: ... gravitational field compared to essentially no such field in the case of asteroids. ... 13:01: Also, mining the moon is going to have a lot of political complications compared to asteroids. 13:14: Asteroids, however, are fair game. 12:22: So Earth is around 2,000 times more massive than the entire asteroid belt. 12:38: Some of you also wondered whether mining the Moon could be more efficient than mining the asteroid belt. 11:01: In the last two episodes we covered the black-hole-information paradox and asteroid mining. 12:14: A few of you wonder whether adding extra mass to Earth from asteroid mining could lead to problems like with our orbit or Earth's gravitational pull. 12:43: Well, the moon is definitely an option for mining, and it's going to have some useful heavy elements from crashed asteroids. 12:49: It's not clear that it's better than near-earth asteroids. 12:53: ... gravitational field compared to essentially no such field in the case of asteroids. ... 13:01: Also, mining the moon is going to have a lot of political complications compared to asteroids. 13:14: Asteroids, however, are fair game.
	2018-06-27: How Asteroid Mining Will Save Earth 00:26: ... the banner of a new company, Planetary Resources, they would mine asteroids for their precious resources and perhaps save the world along the ... 01:11: That resource-- asteroids and the precious materials they contain. 01:16: Astrophysicist Neil deGrasse Tyson predicts that the world's first trillionaire will be an asteroid miner. 01:32: But asteroid mining isn't the same as drilling a hole and hoping black gold spurts out. 01:38: ... and billions of dollars to extract the first dollar's worth of useful asteroid ... 01:50: To answer this question, we need to learn a bit about asteroids. 01:55: Asteroids, along with comets, are leftover material from the formation of the solar system. 02:01: They range from a meter or so to hundreds of kilometers in diameter, and they live primarily in the asteroid belt between Mars and Jupiter. 02:09: ... are also a few smaller groups of asteroids inhabiting different regions and orbits in the inner solar system, ... 02:20: Unlike the more-icy comets of the outer solar system, asteroids are rocky or metallic. 02:33: The most abundant asteroids are C-type or carbonaceous asteroids, constituting 3/4 of all known asteroids. 02:46: C-type asteroids do contain some valuable heavy elements, but not as much as some of the other asteroid types. 02:52: For example, S-type, or silicaceous asteroids, they make up roughly 17% of the asteroids and contain, you guessed it, silicates. 03:11: Third-most abundant are M-type asteroids. 03:18: These are the leftover cores of larger asteroids that were destroyed by collisions. 03:24: If an asteroid is massive enough, it will undergo a process called differentiation. 03:29: During its formation when it's still a giant bowl of molten space rock, heavier iron and nickel will sink to the asteroid's center. 03:37: Smash that asteroid hard enough and you shatter it, exposing a juicy, rich metallic core. 03:43: All asteroid types have the potential to be profitable. 03:55: What loot do asteroids drop-- well, definitely gold and platinum and other precious metals. 04:01: It's not that there's more of this stuff in asteroids than on Earth, it's just that it's more accessible. 04:07: See, the same differentiation process that led to M-type asteroids long ago sucked Earth's crust dry of many of these elements. 04:30: These elements are just more accessible in all but the largest asteroids. 04:34: In fact, much of the precious-metal content of Earth's crust came from old asteroid impacts. 04:40: ... Planetary Resources company estimates that a single 30-meter asteroid may contain $30 billion in platinum alone, and that a 500-meter rock ... 04:54: Kilometer-scale asteroids would be worth many trillions. 05:04: Asteroid miners are going to have to be careful not to crash the value of these materials with oversupply. 05:10: Perhaps the most lucrative asteroid loot will be the stuff that's useful to industry. 05:56: Asteroids are literal gold mines for stuff we want to bring back to Earth, but they also contain materials useful for the mining process itself. 06:27: ... cut back on the amount of mining equipment, and you also limit what asteroids you can ... 06:37: The perfect asteroid has a decent amount of water but also a high abundance of valuable materials. 06:49: ... eventually we'll probably see mining operations in the actual asteroid belt where useful rocks are plentiful, but to start with, it's much ... 06:59: Fortunately for asteroid miners, though less fortunately for the dinosaurs, many asteroids do cross Earth's orbit in their passage around the Sun. 07:08: ... of these near-Earth asteroids can be accessed with relatively little fuel expenditure from Earth ... 07:24: This asteroid prospecting is the current focus of effort for Planetary Resources and its competitors. 07:31: ... know of over 17,000 near-Earth asteroids, but only a small fraction are likely to be cheaply accessible, large ... 07:40: To be short of a profitable composition, robotic prospectors are going to have to visit asteroids. 08:12: So, let's say we find the right asteroid. 08:15: ... we can attempt to mine it on location, so with the orbit of the asteroid, or we can nudge it into a more accessible orbit close to the Earth, ... 08:26: This can be done with a gravitational tractor, which we talked about before, or with rockets fueled by the asteroid's own water supply. 08:34: ... a near-Earth asteroid into lunar orbit was the goal of NASA's Asteroid Redirect Mission, but ... 08:45: It was one of the few missions that had a clear track to massive potential profits and saving the planet from asteroid impact. 08:52: Because if we learned how to land on and push an asteroid to a different course, we could potentially push an Earth-killing asteroid off course. 08:59: OK, we found our asteroid and sent our mining facility. 09:08: Smaller asteroids are expected to be loosely bound rubble piles, so breaking them apart will be relatively easy. 09:15: There are also proposals to scrape regolith, asteroid dust, from the surface, or to magnetically harvest loose surface metals. 09:39: For larger solid asteroids, it may make sense to actually tunnel into their interiors, but that's a way down the track. 09:59: Money talks, and tens of billions or even trillions of dollars per asteroid speaks very loudly. 10:06: Perhaps in just a few decades we'll have mining outposts in the asteroid belt. 10:15: But as the industry scales up in the asteroid belt, real-life human operators may be needed. 02:01: They range from a meter or so to hundreds of kilometers in diameter, and they live primarily in the asteroid belt between Mars and Jupiter. 06:49: ... eventually we'll probably see mining operations in the actual asteroid belt where useful rocks are plentiful, but to start with, it's much easier if ... 10:06: Perhaps in just a few decades we'll have mining outposts in the asteroid belt. 10:15: But as the industry scales up in the asteroid belt, real-life human operators may be needed. 09:15: There are also proposals to scrape regolith, asteroid dust, from the surface, or to magnetically harvest loose surface metals. 03:37: Smash that asteroid hard enough and you shatter it, exposing a juicy, rich metallic core. 08:45: It was one of the few missions that had a clear track to massive potential profits and saving the planet from asteroid impact. 04:34: In fact, much of the precious-metal content of Earth's crust came from old asteroid impacts. 05:10: Perhaps the most lucrative asteroid loot will be the stuff that's useful to industry. 01:38: ... and billions of dollars to extract the first dollar's worth of useful asteroid material. ... 01:16: Astrophysicist Neil deGrasse Tyson predicts that the world's first trillionaire will be an asteroid miner. 05:04: Asteroid miners are going to have to be careful not to crash the value of these materials with oversupply. 06:59: Fortunately for asteroid miners, though less fortunately for the dinosaurs, many asteroids do cross Earth's orbit in their passage around the Sun. 01:32: But asteroid mining isn't the same as drilling a hole and hoping black gold spurts out. 07:24: This asteroid prospecting is the current focus of effort for Planetary Resources and its competitors. 08:34: ... a near-Earth asteroid into lunar orbit was the goal of NASA's Asteroid Redirect Mission, but it was canceled in 2017 due to lack of congressional ... 09:59: Money talks, and tens of billions or even trillions of dollars per asteroid speaks very loudly. 02:46: C-type asteroids do contain some valuable heavy elements, but not as much as some of the other asteroid types. 03:43: All asteroid types have the potential to be profitable. 06:04: ... but they can go towards building infrastructure in space, including more asteroid-mining ... 09:46: The first asteroid-mining missions are slated for the 2020s, but the timetable is very loose. 06:04: ... but they can go towards building infrastructure in space, including more asteroid-mining ... 09:46: The first asteroid-mining missions are slated for the 2020s, but the timetable is very loose. 06:04: ... but they can go towards building infrastructure in space, including more asteroid-mining facilities. ... 09:46: The first asteroid-mining missions are slated for the 2020s, but the timetable is very loose. 00:26: ... the banner of a new company, Planetary Resources, they would mine asteroids for their precious resources and perhaps save the world along the ... 01:11: That resource-- asteroids and the precious materials they contain. 01:50: To answer this question, we need to learn a bit about asteroids. 01:55: Asteroids, along with comets, are leftover material from the formation of the solar system. 02:09: ... are also a few smaller groups of asteroids inhabiting different regions and orbits in the inner solar system, ... 02:20: Unlike the more-icy comets of the outer solar system, asteroids are rocky or metallic. 02:33: The most abundant asteroids are C-type or carbonaceous asteroids, constituting 3/4 of all known asteroids. 02:46: C-type asteroids do contain some valuable heavy elements, but not as much as some of the other asteroid types. 02:52: For example, S-type, or silicaceous asteroids, they make up roughly 17% of the asteroids and contain, you guessed it, silicates. 03:11: Third-most abundant are M-type asteroids. 03:18: These are the leftover cores of larger asteroids that were destroyed by collisions. 03:29: During its formation when it's still a giant bowl of molten space rock, heavier iron and nickel will sink to the asteroid's center. 03:55: What loot do asteroids drop-- well, definitely gold and platinum and other precious metals. 04:01: It's not that there's more of this stuff in asteroids than on Earth, it's just that it's more accessible. 04:07: See, the same differentiation process that led to M-type asteroids long ago sucked Earth's crust dry of many of these elements. 04:30: These elements are just more accessible in all but the largest asteroids. 04:54: Kilometer-scale asteroids would be worth many trillions. 05:56: Asteroids are literal gold mines for stuff we want to bring back to Earth, but they also contain materials useful for the mining process itself. 06:27: ... cut back on the amount of mining equipment, and you also limit what asteroids you can ... 06:59: Fortunately for asteroid miners, though less fortunately for the dinosaurs, many asteroids do cross Earth's orbit in their passage around the Sun. 07:08: ... of these near-Earth asteroids can be accessed with relatively little fuel expenditure from Earth ... 07:31: ... know of over 17,000 near-Earth asteroids, but only a small fraction are likely to be cheaply accessible, large ... 07:40: To be short of a profitable composition, robotic prospectors are going to have to visit asteroids. 08:26: This can be done with a gravitational tractor, which we talked about before, or with rockets fueled by the asteroid's own water supply. 09:08: Smaller asteroids are expected to be loosely bound rubble piles, so breaking them apart will be relatively easy. 09:39: For larger solid asteroids, it may make sense to actually tunnel into their interiors, but that's a way down the track. 03:29: During its formation when it's still a giant bowl of molten space rock, heavier iron and nickel will sink to the asteroid's center. 02:33: The most abundant asteroids are C-type or carbonaceous asteroids, constituting 3/4 of all known asteroids. 03:55: What loot do asteroids drop-- well, definitely gold and platinum and other precious metals. 02:09: ... are also a few smaller groups of asteroids inhabiting different regions and orbits in the inner solar system, including some ... 04:07: See, the same differentiation process that led to M-type asteroids long ago sucked Earth's crust dry of many of these elements.
	2018-05-09: How Gaia Changed Astronomy Forever 07:38: It's tracked over 14,000 asteroids and other solar system objects, and found many new ones. 07:44: This is useful for future asteroid mining missions, and to identify potentially, Earth-threatening objects. 07:38: It's tracked over 14,000 asteroids and other solar system objects, and found many new ones.
	2018-03-07: Should Space be Privatized? 04:28: Asteroid mining seems likely to drive the next wave of private enterprise, because the potential profits are astronomical. 10:23: We'll start small, maybe a skateboard tied to a weather balloon and work up to launching sportscast to the asteroid belt. Baby steps, right? 04:28: Asteroid mining seems likely to drive the next wave of private enterprise, because the potential profits are astronomical.
	2018-02-21: The Death of the Sun 07:28: ... is now a lonely desolate world orbiting out in the old location of the asteroid belt, or perhaps it didn't quite make ...
	2018-01-31: Kronos: Devourer Of Worlds 08:59: It should be possible to deflect an asteroid into an elliptical orbit that takes it near both the Earth and Jupiter. 09:10: The asteroid loses angular momentum in the process, but it regains it as it flies by Jupiter. 09:15: Essentially, we steal angular momentum from Jupiter via the asteroid, which increases our orbit. 09:22: ... a big enough asteroid, one encounter per several thousand years should be enough to maintain ... 09:10: The asteroid loses angular momentum in the process, but it regains it as it flies by Jupiter.
	2017-12-20: Extinction by Gamma-Ray Burst 00:35: ... a good chance we can prevent the most imminent, like asteroid strikes, or at least deal with their effects, like the damage caused by ... 01:41: Some of these mass extinctions were due to giant asteroid impact, including the most recent, which wiped out the dinosaurs 65 million years ago. 01:53: In fact, we've already talked about asteroid impacts and how to deflect them. 11:06: A typical asteroidal density is 2,000 kilograms per cubic meter. 01:41: Some of these mass extinctions were due to giant asteroid impact, including the most recent, which wiped out the dinosaurs 65 million years ago. 01:53: In fact, we've already talked about asteroid impacts and how to deflect them. 00:35: ... a good chance we can prevent the most imminent, like asteroid strikes, or at least deal with their effects, like the damage caused by gamma-ray ... 11:06: A typical asteroidal density is 2,000 kilograms per cubic meter.
	2017-12-13: The Origin of 'Oumuamua, Our First Interstellar Visitor 00:12: This is the first time we've ever seen an asteroid like object that came to us from interstellar space. 00:36: ... that constantly monitors the sky for moving or variable objects like asteroids or ... 02:39: That suggests the surface to at least one meter depth is rocky like an asteroid rather than icy like a comet. 03:00: ... previously observed asteroid-- indeed, every previously observed everything in our solar system-- moves ... 06:38: Given how many stars there are, there should be a ton of asteroidal objects floating around in interstellar space. 00:36: ... that constantly monitors the sky for moving or variable objects like asteroids or ...
	2017-11-29: Citizen Science + Zero-Point Challenge Answer 01:38: Shoemaker, in particular, was incredibly active, discovering or co-discovering 32 comets, 377 minor planets, and over 800 asteroids.
	2017-02-15: Telescopes of Tomorrow 08:49: We'll spot countless fast-moving objects in our own solar system, including potentially hazardous asteroids that could one day impact the Earth.
	2016-10-12: Black Holes from the Dawn of Time 04:10: First of all, we aren't going to find primordial black holes less than around a billion tons, or the mass of a small asteroid. 06:17: ... we're left with are either lots of PBHs with masses similar to a large asteroid like Ceres, so around 10 to the power of 21 kilograms, or a much smaller ... 08:40: If PBHs are closer to the mass of a large asteroid, then they're too low in mass and probably moving too fast to do any gravitational damage. 09:11: ... around a billion tons-- these would be much more abundant than asteroid mass ...
	2016-09-14: Self-Replicating Robots and Galactic Domination 04:40: ... applications, like asteroid mining, Dyson swarm construction, and terraforming-- really any ... 05:25: After several decades, it decelerates into a neighboring star system, and parks in orbit, or lands on a nice, big asteroid or gas giant moon. 04:40: ... applications, like asteroid mining, Dyson swarm construction, and terraforming-- really any large-scale ...
	2016-08-24: Should We Build a Dyson Sphere? 05:16: ... the sun, we'd probably need to devour Venus, Mars, and a good number of asteroids and outer solar system moons, too, assuming we want to leave Earth ... 05:50: Real companies are gearing up to do autonomous asteroid mining, perhaps within a couple of decades. 05:16: ... the sun, we'd probably need to devour Venus, Mars, and a good number of asteroids and outer solar system moons, too, assuming we want to leave Earth ...
	2016-08-10: How the Quantum Eraser Rewrites the Past 13:11: ... 404, Hoder Not Found had a great idea in which you collect asteroids and put them in orbit around the Earth, ready to sling at any oncoming ...
	2016-08-03: Can We Survive the Destruction of the Earth? ft. Neal Stephenson 00:35: In that case, we're pretty sure that a giant asteroid or comet was the culprit, slamming into the Chicxulub peninsula in modern Mexico. 01:47: Some may not be so easy to deal with as an asteroid impact. 03:01: ... the most obvious example would be just a big asteroid coming in and striking the Earth on short notice, which would be-- could ... 03:28: But in the case of a big asteroid impact or a nearby supernova, it could come with so little warning that we might not have time to do much about it. 06:02: Any asteroid or comet bigger than a few kilometers diameter has the potential to cause extreme climate change and mass extinction. 06:42: ... us at least some warning and are somewhat easier to see coming than an asteroid. ... 07:37: It only takes a couple of lazy generations to miss that big asteroid. 03:01: ... the most obvious example would be just a big asteroid coming in and striking the Earth on short notice, which would be-- could be as ... 01:47: Some may not be so easy to deal with as an asteroid impact. 03:28: But in the case of a big asteroid impact or a nearby supernova, it could come with so little warning that we might not have time to do much about it.
	2016-07-06: Juno to Reveal Jupiter's Violent Past 03:32: ... worrying comets that cross its orbit, it also perturbs the orbits of asteroids in the asteroid belt and can send them plummeting towards the ... 03:58: At first, there was the gassy, dusty protoplanetary disk, and then a mess of asteroids and planetesimals left over from the formation of the planets. 07:09: The asteroid belt is also an interesting clue. 09:13: ... have a tiny Mars, no super Earths, a weird, mixed up asteroid belt, and an early obliteration of Earth's surface, and, perhaps, a ... 03:32: ... that cross its orbit, it also perturbs the orbits of asteroids in the asteroid belt and can send them plummeting towards the ... 07:09: The asteroid belt is also an interesting clue. 09:13: ... have a tiny Mars, no super Earths, a weird, mixed up asteroid belt, and an early obliteration of Earth's surface, and, perhaps, a missing ... 03:32: ... worrying comets that cross its orbit, it also perturbs the orbits of asteroids in the asteroid belt and can send them plummeting towards the ... 03:58: At first, there was the gassy, dusty protoplanetary disk, and then a mess of asteroids and planetesimals left over from the formation of the planets.
	2016-03-16: Why is the Earth Round and the Milky Way Flat? 06:56: For example, the 578-kilometer-diameter asteroid Vesta is lumpy, but the 1,000-kilometer Ceres is spherical.
	2015-12-09: How to Build a Black Hole 11:20: Now, in the last full episode, we talked about how to stop a killer asteroid from hitting the earth. 11:27: ... of the gravitational tractor, you could just land a spacecraft on the asteroid and push it with its ... 11:35: ... amount of fuel to pull by a gravitational tractor as it would to push an asteroid by landing a rocket on it, assuming that the rocket can push with ... 11:47: Now, that's tricky because the asteroid will certainly be rotating. 12:08: Max Shifter asked about the plausibility of directing a killer asteroid into the sun. 12:13: So even the largest asteroid hitting the sun would barely make a splash. 12:57: A lot of people point out that One-Punch Man could easily destroy a killer asteroid. 12:13: So even the largest asteroid hitting the sun would barely make a splash.
	2015-11-25: 100 Years of Relativity + Challenge Winners! 00:03: Today we have a solution to our killer asteroid challenge episode, but before we get to that there's something very special about today. 01:39: In our recent challenge episode, I asked whether you could save the Earth from a killer asteroid. 01:43: In a hypothetical scenario, the asteroid Apophis will buzz by the Earth in 2029 but then hit the Earth in 2036. 01:57: ... pulsed fusion drive spacecraft is to intercept the asteroid in the 2029 pass and pull Apophis 25,000 kilometers ahead of its would ... 02:35: That way we don't need to worry about the asteroid's initial 30 kilometer per second velocity at all. 02:39: In the asteroid's frame, its starting velocity is zero. 02:45: The x-axis is the orbital path of the asteroid. 05:16: We're trying to pull the entire asteroid, so we have to include its mass as part of the spacecraft mass. 05:40: Rearranging all of this, we get this equation for the ratio of fuel mass to asteroid mass. 05:54: However, remember that the thrusters have to be angled to miss the asteroid, otherwise we'll just push the extra backwards. 06:21: ... have thrusters pointing in at least two directions on either side of the asteroid to cancel the sideways component ... 06:34: Putting this together, we get a ratio of fuel mass to asteroid mass of 5.3 by 10 to the minus 7. 01:43: In a hypothetical scenario, the asteroid Apophis will buzz by the Earth in 2029 but then hit the Earth in 2036. 00:03: Today we have a solution to our killer asteroid challenge episode, but before we get to that there's something very special about today. 05:40: Rearranging all of this, we get this equation for the ratio of fuel mass to asteroid mass. 06:34: Putting this together, we get a ratio of fuel mass to asteroid mass of 5.3 by 10 to the minus 7. 02:35: That way we don't need to worry about the asteroid's initial 30 kilometer per second velocity at all. 02:39: In the asteroid's frame, its starting velocity is zero. 02:35: That way we don't need to worry about the asteroid's initial 30 kilometer per second velocity at all.
	2015-11-18: 5 Ways to Stop a Killer Asteroid 00:03: It's a scientific fact that the planet Earth will be hit by cataclysmic asteroids in the future. 00:52: And the Chelyabinsk asteroid came in at a shallow angle, so it had lots of atmosphere to burn up in. 01:16: So when can we expect the next killer asteroid? 02:30: ... asteroid of this magnitude probably killed the dinosaurs 65 million years ago, ... 02:58: ... to find and track most of the biggest, one kilometer plus, comets or asteroids that cross Earth's ... 05:30: The pressure of the nuke, and of the ejected asteroid bits, will push the NEO off target. 05:36: A regular nuke would be fine for smaller asteroids. 05:47: Seriously, arm a spacecraft with a cosmic-sized can of spray paint, and color one side of the asteroid white. 06:44: The asteroid or comet is heading straight for us. 07:04: My favorite idea so far is the Hypervelocity Asteroid Intercept Vehicle. 07:20: This uses the nuke's energy much more efficiently, sending shockwaves through the asteroid, that will break it into much smaller pieces. 07:27: ... of HAIV team, a one megaton H-bomb should break up a 500 meter asteroid nicely, although it depends on the structure of the ... 07:44: For a giant asteroid, you're going to need a gigaton blast. 08:31: ... assuming no giant asteroids hit in the meantime, I'll see you on the next episode of "Space Time." ... 05:30: The pressure of the nuke, and of the ejected asteroid bits, will push the NEO off target. 07:04: My favorite idea so far is the Hypervelocity Asteroid Intercept Vehicle. 07:27: ... of HAIV team, a one megaton H-bomb should break up a 500 meter asteroid nicely, although it depends on the structure of the ... 05:47: Seriously, arm a spacecraft with a cosmic-sized can of spray paint, and color one side of the asteroid white. 00:03: It's a scientific fact that the planet Earth will be hit by cataclysmic asteroids in the future. 02:58: ... to find and track most of the biggest, one kilometer plus, comets or asteroids that cross Earth's ... 05:36: A regular nuke would be fine for smaller asteroids. 08:31: ... assuming no giant asteroids hit in the meantime, I'll see you on the next episode of "Space Time." ...
	2015-11-11: Challenge: Can you save Earth from a Killer Asteroid? 00:06: This question is going to draw on two episodes-- our interstellar travel episode from a few weeks ago and next week's episode on killer asteroids. 00:18: The near-Earth asteroid, Apophis, is set to buzz by Earth on April 13, 2029 and then again exactly seven years later on April 13, 2036. 00:40: This 325-meter-diameter asteroid weights around 30 billion kilograms, and it's traveling at 30 kilometers per second. 01:03: ... spacecraft will hover just in front of the asteroid and act as a gravitational tractor, slowly increasing the asteroid speed ... 02:15: ... at gmail.com by November 20 and use the subject line, Spacetime Killer Asteroid ... 00:18: The near-Earth asteroid, Apophis, is set to buzz by Earth on April 13, 2029 and then again exactly seven years later on April 13, 2036. 02:15: ... at gmail.com by November 20 and use the subject line, Spacetime Killer Asteroid Challenge. ... 01:03: ... the asteroid and act as a gravitational tractor, slowly increasing the asteroid speed by the mutual gravitational attraction over the seven years before the ... 00:40: This 325-meter-diameter asteroid weights around 30 billion kilograms, and it's traveling at 30 kilometers per second. 00:06: This question is going to draw on two episodes-- our interstellar travel episode from a few weeks ago and next week's episode on killer asteroids.
	2015-10-28: Is The Alcubierre Warp Drive Possible? 05:25: Thicken the walls of the warp field, and you get the negative mass/energy requirement down to the equivalent of maybe the moon or even an asteroid.
	2015-10-22: Have Gravitational Waves Been Discovered?!? 09:40: Large bodies like asteroids are rare enough in interstellar space that hitting one is very unlikely.
	2015-10-15: 5 REAL Possibilities for Interstellar Travel 01:19: It's only 4.4 light years away, but we have to get there before the Curbles and the impending K1 asteroid that's on its way.
	2015-04-29: What's the Most Realistic Artificial Gravity in Sci-Fi? 06:58: ... also estimated that each halo has as much mass as the entire asteroid belt. So new question, do any sci-fi franchises get all the physics ...
	2015-03-18: Can A Starfox Barrel Roll Work In Space? 08:56: Culwin brought up that Ceres is actually the largest asteroid. 09:00: I thought that a dwarf planet and an asteroid designation were mutually exclusive, they appear not to be. 09:05: But even if Ceres is an asteroid, it's only about three and a half times as massive as 4 Vesta, still not enough energy to destroy the Earth. 09:00: I thought that a dwarf planet and an asteroid designation were mutually exclusive, they appear not to be.
	2015-03-11: What Will Destroy Planet Earth? 00:00: Lots of unpleasant things from nuclear war to asteroid impacts could destroy life on Earth. 01:43: So let's move on to the next obvious suspect-- asteroids. 01:58: Even 4-Vesta, the biggest object that's still classified as an asteroid, would only care about half a percent of the required energy. 02:15: But asteroids orbit the sun about 35 times slower than that. 02:27: Now with those speeds, an object could only carry enough energy to destroy Earth if it had a huge mass, which asteroids don't. 02:44: Well, Earth and Mars' field gravitational pulls not just from the sun, but also from the other plants-- and from big asteroids too. 00:00: Lots of unpleasant things from nuclear war to asteroid impacts could destroy life on Earth. 01:43: So let's move on to the next obvious suspect-- asteroids. 02:15: But asteroids orbit the sun about 35 times slower than that. 02:27: Now with those speeds, an object could only carry enough energy to destroy Earth if it had a huge mass, which asteroids don't. 02:44: Well, Earth and Mars' field gravitational pulls not just from the sun, but also from the other plants-- and from big asteroids too. 02:27: Now with those speeds, an object could only carry enough energy to destroy Earth if it had a huge mass, which asteroids don't. 02:15: But asteroids orbit the sun about 35 times slower than that.

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