Cosmic Queries: Asteroids, Comets and Meteor Storms

Can’t tell the difference between asteroids, comets, meteoroids, meteors and meteorites? Never fear… Neil deGrasse Tyson explains them all in this episode of Cosmic Queries.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:01Neil deGrasse Tyson?

  Welcome to StarTalk. Your place in the universe where science and pop culture collide. StarTalk begins right now.

• 0:21Neil deGrasse Tyson?

  This is StarTalk, the Cosmic Queries Edition. I'm Neil deGrasse Tyson, in studio with Chuck Nice.

• 0:28Speaker 01

  Hey Neil.

• 0:29Neil deGrasse Tyson?

  Hey Chuck.

• 0:30Speaker 01

  Hey, good to see you, man.

• 0:31Neil deGrasse Tyson?

  This is not our first rodeo.

• 0:32Speaker 01

  No, it is not.

• 0:33Neil deGrasse Tyson?

  It is not.

• 0:34Speaker 01

  No, it is not.

• 0:35Neil deGrasse Tyson?

  So, what have we done? We've collected questions from our fanbase, basically. Those who like us on Facebook, or-

• 0:43Speaker 01

  Or Twitter.

• 0:44Neil deGrasse Tyson?

  Or, yeah.

• 0:45Speaker 01

  Or Google+.

• 0:46Neil deGrasse Tyson?

  Or Google+. And they've been, we've solicited questions from them on the topic of-

• 0:50Speaker 01

  Asteroids.

• 0:51Neil deGrasse Tyson?

  Asteroids.

• 0:52Speaker 01

  Yes. Great video game back in the day, by the way, I just gotta say.

• 0:56Neil deGrasse Tyson?

  You're dating yourself.

• 0:59Neil deGrasse Tyson?

  Yeah, and that impung. You were totally rocking, rocking the, rocking the bar scene, I'm sure. No, I like asteroids too, and I have a bit of trivia about asteroids later on, if you're interested. The game Asteroids.

• 1:10Speaker 01

  Okay.

• 1:11Neil deGrasse Tyson?

  If you remember, and if you're interested.

• 1:12Speaker 01

  I will, I will keep that in mind.

• 1:13Neil deGrasse Tyson?

  So you've got them all, so let's, let's rock the house.

• 1:15Speaker 01

  Yep, and let us, let us remind the audience that these are questions that you have not seen.

• 1:20Neil deGrasse Tyson?

  I've not seen, and I can't claim to, this is not stump Dr. Tyson.

• 1:23Speaker 01

  No, it's not.

• 1:24Neil deGrasse Tyson?

  It's not, but it's, I don't want to see them in advance, because it's more fun hearing them right, right up front.

• 1:29Speaker 01

  And we get to hear your truly spontaneous answer to these things.

• 1:33Neil deGrasse Tyson?

  You hear me fumble over, and if I don't know an answer, I'll just say, "Go next."

• 1:36Speaker 01

  Right, exactly. Right.

• 1:38Neil deGrasse Tyson?

  And we'll end the hour with the, the lightning round.

• 1:41Speaker 01

  Which is, well, actually, it was funny, I got a tweet that somebody retweeted from one of our former Cosmic Queries, and it, the question, um, let me see if I can get it right. Uh, "Can there be time without gravity, and, or motion? Can there be time without motion?" Uh, and that's what the question was. Answer, Neil, colon, "No." Moving on.

• 2:09Neil deGrasse Tyson?

  They can't be the measurement of time without motion.

• 2:11Speaker 01

  Exactly.

• 2:12Neil deGrasse Tyson?

  There's course time without motion.

• 2:13Speaker 01

  Alright, so listen, let's jump right into this and let's start off with Deepak Argwal is the person who sent this in.

• 2:21Neil deGrasse Tyson?

  How come we never know anyone with the names of people who ask questions?

• 2:24Speaker 01

  I don't know, man, but I love it.

• 2:26Neil deGrasse Tyson?

  Deepak Argwal.

• 2:27Speaker 01

  I wanna hang out at a cocktail party with a guy named Deepak Argwal.

• 2:31Neil deGrasse Tyson?

  Okay, go on.

• 2:32Speaker 01

  Would it be possible to go through a brief summary of the nomenclature of asteroid? Minor planet, comet, meteor, meteoroid, etc. Sometimes I think people, including myself, toss these terms around are not completely sure of what all the differences may be.

• 2:47Neil deGrasse Tyson?

  Okay.

• 2:48Speaker 01

  Great question, because I'm in that group that he talks about.

• 2:50Neil deGrasse Tyson?

  Are you ready?

• 2:51Speaker 01

  Please, go right ahead.

• 2:52Neil deGrasse Tyson?

  In the solar system, there's a star. And we call that the sun. By the way, it wasn't always thought of as a star. The star was what was on the sky. And the sun was what we saw in our daytime sky. Those two, those two words were not historically the same thing. They're not the same in the Bible. Right, they're two separate things. And so it would be much later that we would learn that the stars of the night sky are just like the sun, except much, much farther away.

• 3:20Speaker 01

  Right.

• 3:20Neil deGrasse Tyson?

  Okay, so we have the sun. Then we have what are called planets. Originally, planets were wanderers against the background sky. And the Greeks first named them, planetes, meaning wanderers. And there were seven wanderers, now traceable to the names we give to the seven days of the week.

• 3:37Speaker 01

  Gotcha.

• 3:37Neil deGrasse Tyson?

  So the seven wanderers were Mercury, Venus, Mars, Jupiter, Saturn, the sun and the moon.

• 3:42Speaker 01

  Gotcha.

• 3:43Neil deGrasse Tyson?

  All of those moved against the background stars. And so you, some are easy. Sunday is sun, Monday is moon, and Saturday is Saturn. Right? So, so those were planets originally. And no one knew anything about moons or asteroids or, but comets were easy. Okay, we knew about comets and we, comet is made mostly of ice. And as it comes near the sun, the ice evaporates, sublimes, if you want to be technically accurate. And it grows a tail, boom, comet, no doubt about it.

• 4:10Speaker 01

  Okay.

• 4:12Neil deGrasse Tyson?

  Once Copernicus came along, he said, "Wait a minute, the sun is in the middle and we go around the sun, and so we're a planet, the sun isn't." Then planet got redefined to just be stuff that went around the sun. Gotcha. Mercury, Venus, Earth, Mars, Jupiter, and Saturn. Then we discovered Uranus and Neptune, we discovered Pluto, then we discovered asteroids. Asteroids are craggy chunks of rock that orbit primarily between Mars and Jupiter. They're really tiny, they're so small in a telescope, you cannot see their surface. Gotcha. Distant stars, you can't see their surface through a telescope either, they're so far away. So, people said, "Well, if they're really tiny, on a, in an image, like a star, but they're not stars, they're asteroids." So they're tiny? Oh, star-like. Star-like.

• 4:57Neil deGrasse Tyson?

  Asteroids. Star-like. So, those are asteroids. Gotcha. Alright, so now, as an asteroid comes crashing through our atmosphere and is rendered a glow, it is a meteor. Gotcha. If any of it survives and you can pick it up on the ground, it's a? Meteorite. Meteorite. That I didn't know. There you go. Gotcha. Alright, now, since Pluto's episode... Poor Pluto. Yeah. Uh, when we redefined planet to mean that which has, is round and has cleared out its orbit of miscellaneous debris, of, of most of the debris that was there when the solar system formed. So, Earth has cleaned up most of what was in its orbit. Right. Okay? At least we still get hit, but we cleaned up most of it. Pluto has not.

• 5:41Neil deGrasse Tyson?

  Pluto is in a zone in the outer solar system called the Kuiper Belt. There is more mass in the Kuiper Belt than the mass of Pluto itself. Pluto does not own the Kuiper Belt. Right. Whereas we own our, our orbit. You own my house. Exactly. Earth. So, then we came up with a new word for round objects that don't own their space. And those are, and those are dwarf planets. Dwarf planets? Exactly. And so, one of the asteroids is big enough to be round, it doesn't own its space because it's in the asteroid belt, that is, uh, Ceres, is big enough to be round, and so that's also a dwarf planet. Okay. Ceres is the root, uh, Ceres was the goddess of harvest, and cereal comes from the name Ceres.

• 6:22Speaker 01

  Nice.

• 6:23Neil deGrasse Tyson?

  I know. It's all, we're just rocking it.

• 6:26Speaker 01

  Wow.

• 6:26Neil deGrasse Tyson?

  And, okay, so now, uh, minor planet is basically all asteroids, and I think they include comets in that as well.

• 6:35Speaker 01

  Okay.

• 6:35Neil deGrasse Tyson?

  So, everything that does not have a round shape, uh, basically we call a minor planet.

• 6:39Speaker 01

  You're gonna call it a minor planet?

• 6:40Neil deGrasse Tyson?

  Kind of minor planet, that's right.

• 6:41Speaker 01

  It's, it's the catch-all drawer.

• 6:44Neil deGrasse Tyson?

  It's the catch drawer.

• 6:44Speaker 01

  It's the catch drawer for the cosmos. Minor planet.

• 6:47Neil deGrasse Tyson?

  So that was a great question, just, uh, helping, oh, there's also meteoroid, which is a tiny asteroid.

• 6:54Speaker 01

  Okay.

• 6:55Neil deGrasse Tyson?

  That is most of what you see as the shooting stars in the night sky. So the meteoroid becomes a, becomes a meteor, becomes a meteorite.

• 7:02Speaker 01

  Gotcha. Okay, okay. So streaking across the sta- sky, tiny little, it's a meteoroid, lands on the ground, it's still intact, meteorite.

• 7:10Neil deGrasse Tyson?

  Meteorite. Usually the meteorite's vaporized, but that's, who's, who's counting?

• 7:14Speaker 01

  Exactly. Alright, cool.

• 7:16Neil deGrasse Tyson?

  Man, that took almost the whole segment. Holy cow.

• 7:18Speaker 01

  But guess what? It was good, because now we have all of those definitions going forward.

• 7:23Neil deGrasse Tyson?

  So we can just rock the rest of it, okay?

• 7:24Speaker 01

  Cause I'm serious, I really, I'm glad you did that, because some of those things, I get confused.

• 7:29Neil deGrasse Tyson?

  You, even Chuck Nice gets confused.

• 7:32Speaker 01

  Things confused, but no longer.

• 7:34Neil deGrasse Tyson?

  So you got another one? I don't know if we can fit it in the last 20 seconds of this segment. What do you got for me?

• 7:38Speaker 01

  Okay, what's the reason behind some asteroids are incredibly metal-rich and some are just big rocks?

• 7:42Neil deGrasse Tyson?

  That is an awesome question. Too long, in the next 12 seconds, I can't answer it in 12 seconds.

• 7:49Speaker 01

  Okay, then, you know what? Cliffhanger.

• 7:51Neil deGrasse Tyson?

  Cliffhanger, you gotta come back to StarTalk Radio. We're talking about asteroids in the Cosmic Queries part, which I like to think of as StarTalk After Hours.

• 8:18Neil deGrasse Tyson?

  We're back to Cosmic Queries of StarTalk. I'm Yulda Rast Tyson with Chuck Nice.

• 8:24Speaker 01

  Yes, right.

• 8:24Neil deGrasse Tyson?

  Chuck tweeting at ChuckNiceComic.

• 8:26Speaker 01

  That's right, that's correct, sir.

• 8:27Neil deGrasse Tyson?

  I follow you.

• 8:28Speaker 01

  I follow you too.

• 8:29Neil deGrasse Tyson?

  You make me laugh every now and then.

• 8:31Speaker 01

  Oh, well, thank you.

• 8:33Speaker 01

  I think I said that thank you too quickly.

• 8:35Neil deGrasse Tyson?

  Yeah, you did. You made me laugh sometimes.

• 8:40Neil deGrasse Tyson?

  Alright, so you're reading me questions that we've called from the internet. I've not seen them, but it's not stump Dr. Tyson.

• 8:45Speaker 01

  No, it isn't.

• 8:46Neil deGrasse Tyson?

  It's fresher, I think, if I'd never heard of them before.

• 8:48Speaker 01

  And right before, we had a little cliffhanger. John Savage wanted to know, what's the reason behind why some asteroids are incredibly rich metal, or metal-rich, and some are just big rocks?

• 8:59Neil deGrasse Tyson?

  That's a big, that's an excellent question. So, so it turns out, a very small fraction of asteroids are metal-rich. Most of the rest are rocky, okay? They're non-metallic. And it comes about for a really good reason. Well, it's the fact that we find asteroids this way, tells us a lot about their origin. When the solar system formed, it's a huge gas cloud. And that gas cloud is a mixture of most of the elements on the periodic table. There's hydrogen, and helium, all the way on to cobalt, nitrogen, oxygen, silicon, iron. All these elements are just mixed in the gas cloud. And the heavy elements are not so much, but they're there.

• 9:38Speaker 01

  Right.

• 9:39Neil deGrasse Tyson?

  It's mostly hydrogen and helium.

• 9:40Speaker 01

  Right.

• 9:41Neil deGrasse Tyson?

  The sun gets, is mostly hydrogen and helium. It's got like, that's where most of the hydrogen and helium went. Alright, if you start making objects, out in the solar system, once you, most of the hydrogen and helium is taken away, you have all the rest of these elements, and they start getting made. If that object was ever molten, as most of these are when they form, who's gonna sink to the bottom?

• 10:05Speaker 01

  The heaviest.

• 10:06Neil deGrasse Tyson?

  The heavy stuff.

• 10:07Speaker 01

  Right.

• 10:07Neil deGrasse Tyson?

  The iron, the platinum, the gold, the iridium, the osmium, the tungsten, all gonna sink to the bottom. And the lighter stuff is gonna flow to the top, which is the, what it's called silicate, so, rocks.

• 10:19Speaker 01

  Rocks, right.

• 10:20Neil deGrasse Tyson?

  Compared to iron, rock is light, right?

• 10:22Speaker 01

  So true.

• 10:23Neil deGrasse Tyson?

  So, so those rise to the top. And so, now you have a body that has formed in space.

• 10:32Neil deGrasse Tyson?

  And then another object smashes it to smithereens. And the smithereens are now asteroids.

• 10:39Speaker 01

  Right.

• 10:39Neil deGrasse Tyson?

  So now you have rocky asteroids made from the crust and mantle of that object.

• 10:43Speaker 01

  Cause it came from that part, from the rocky part.

• 10:45Neil deGrasse Tyson?

  Came from the rocky part. And then you have metallic asteroids. That precious few, the precious atoms that collected in the center, ready to be presorted for our pleasure.

• 10:56Speaker 01

  Ah, yes. Yes.

• 10:58Neil deGrasse Tyson?

  So, so the, the geologist calls that differentiation, uh, not to be confused with what you do in calculus.

• 11:04Speaker 01

  Right. Okay.

• 11:06Neil deGrasse Tyson?

  Just so you know.

• 11:06Speaker 01

  Just so you know, for those of you who are wondering, cause I already knew that.

• 11:10Neil deGrasse Tyson?

  You were, yeah, for the geek's act, uh, yeah, the, the geologist meant no harm by saying differentiation, but that's, that's what that is. So that's why Earth's core is mostly iron. There's, there's a lot of iron in the universe and it's heavy and it goes down to the middle. And all the other heavy stuff, stuff is there with it.

• 11:26Speaker 01

  There you go. There you go, John. Heavy metal. It's not just the music. Okay?

• 11:30Neil deGrasse Tyson?

  And by the way, there's also a lot of iron in our crust. A lot of it is bound with other elements to make it light. But, uh, and you find iron ore that comes through. This is where, how we do our mining.

• 11:40Speaker 01

  Right.

• 11:40Neil deGrasse Tyson?

  It's a lot of what goes on in mining, but if we were at the core, there would be no mining. You just reach down, pick up the iron.

• 11:45Speaker 01

  And it's there.

• 11:46Neil deGrasse Tyson?

  It's there. It's everywhere.

• 11:47Speaker 01

  We're filthy with iron.

• 11:48Neil deGrasse Tyson?

  Right. Do we mine rock? No, it's just there. Okay.

• 11:52Speaker 01

  All right. Very cool. Give me, give it to me. Move on. Um, this is Todd Smith. Look at that. What a normal name. Uh, is the asteroid belt a failed planet or just coagulated debris field?

• 12:04Neil deGrasse Tyson?

  Ew, that sounds like a disease. You have coagulated debris fields. So, uh, we don't know what the mass of the asteroid belt might've been in the early solar system.

• 12:14Speaker 01

  Uh huh.

• 12:15Neil deGrasse Tyson?

  I mean, I might have colleagues who work in that field who would give a good guess, but I don't work in that field, so I couldn't even guess for you. But I can tell you how much the thing weighs now.

• 12:24Speaker 01

  Really?

• 12:24Neil deGrasse Tyson?

  Yes. Okay. You ready?

• 12:26Speaker 01

  Yeah.

• 12:26Neil deGrasse Tyson?

  Bring all the asteroid pieces together and they will sum to about 5% of the mass of our moon.

• 12:33Speaker 01

  What?

• 12:34Neil deGrasse Tyson?

  You heard what I said. You heard what I said.

• 12:37Speaker 01

  That's it?

• 12:38Neil deGrasse Tyson?

  That's.

• 12:40Neil deGrasse Tyson?

  What? Registered? You say that again?

• 12:41Speaker 01

  Yeah.

• 12:42Neil deGrasse Tyson?

  That's.

• 12:42Speaker 01

  Hey, that's it.

• 12:44Neil deGrasse Tyson?

  So that's why when they show these science fiction stories of, oh, we've reached the asteroid belt and they're dodging them left and right. No. Every mission we've sent to the outer solar system did not have to dodge asteroids. All right. I am so disappointed. Yeah. So there's, there's a zillion of probably a million asteroids, but they're very widely spread apart. And, and in fact, the biggest asteroid, Ceres, is more massive than like the rest of all the asteroids combined. And that's the then in series is little, right? So there's not much stuff out there. So to say this was once a mighty planet that I'm not ready to say that. Gotcha. There's not much there to begin with. So if you put the moon out there and smash it to smithereens,

• 13:25Neil deGrasse Tyson?

  it would have an awesome, it would be a 20 times more awesome asteroid belt than what we have right now. Just our moon. Yeah. Except the moon doesn't have much iron. Uh, moon is an anomaly among large spherical. It should have an iron core, given its size. Right. Cause it would have had all those ingredients and it would have differentiated out, but it has hardly any iron, which is what led to the, this wasn't asked, but I got to get it off my chest. Right? Which is what led to the impact theory for hypothesis for the formation of the moon.

• 13:51Speaker 01

  Okay. That earth formed, we already differentiated our stuff. Somebody else comes along and side

• 13:57Neil deGrasse Tyson?

  swipes our crust. Bang. And all of our crustal material becomes the moon. And that's why there's a good match between the moon and our crust and the moon has hardly any iron. Yeah. See?

• 14:06Speaker 01

  And I thought you were gonna say that's why we have the theory that the moon is anemic, because it has very little iron. Nice. That's very medical of you. Yeah. What else you got? Let's move on. Tim Pilgrim, um, wants to know, would it be possible to use an asteroid as an interplanetary bus service? Uh, so you jump on the asteroid while it passes earth and then you jump off it again when it's going around Mars. I love it. Really? I love it. Okay.

• 14:33Neil deGrasse Tyson?

  But it so would not work. Okay. Why not? Because you have to, you, you have to catch up with the asteroid to step onto it. And by the time you've done that, you could get to where you're going by. So in other words, it's like driving a Ferrari to catch a bus. Yeah, exactly. If you had the Ferrari, you don't need the bus. There you go. Right. Now, if you somehow found a way to Get the asteroid to stop and start, but whatever power that is, you can, you don't need the asteroid.

• 14:58Speaker 01

  Right.

• 14:58Neil deGrasse Tyson?

  You just.

• 14:59Speaker 01

  You just harness that power.

• 15:00Neil deGrasse Tyson?

  You got your own spaceship. So it's a nice idea, but uh, no, I think maybe he's thinking of those cartoon things where it goes by and you reach onto it. And then your army elongates.

• 15:10Speaker 01

  Right.

• 15:10Neil deGrasse Tyson?

  But then you just get snatched along. You, you, you snap back and then you're with it. Uh, but no, no, the physics prevents that from being a useful idea, but it's sound. Sounds like a really cool idea because asteroids are going everywhere.

• 15:21Speaker 01

  Right.

• 15:22Neil deGrasse Tyson?

  Yeah.

• 15:22Speaker 01

  Yeah. Yeah. Uh, it's well, listen, man, you get an A for creativity. F for practicality.

• 15:29Neil deGrasse Tyson?

  Okay.

• 15:30Speaker 01

  Yeah. But, uh, okay. Let's move on.

• 15:33Neil deGrasse Tyson?

  What else you got?

• 15:33Speaker 01

  This is Alex Stevens.

• 15:35Neil deGrasse Tyson?

  Mm hmm.

• 15:36Speaker 01

  Alex wants to know, interstellar asteroids, are there objects that enter the solar system? From interstellar travel? Also, can orbiting solar systems ever leave the sun's gravity and fly toward another star? Please answer this one. I've been dying to know.

• 15:55Neil deGrasse Tyson?

  Okay. Uh, so that's excellent question. First, our studies of the formation of solar systems tell us. That our solar system might've had 20 or 30 planets when it was born.

• 16:04Speaker 01

  What?

• 16:05Neil deGrasse Tyson?

  Where are they now?

• 16:06Speaker 01

  That's what I want to know.

• 16:07Neil deGrasse Tyson?

  Have escaped. What happens is they, they end up on unstable orbits and they get flung to interstellar space and they're called rogue planets. They are homeless planets wandering the galaxy without a host star.

• 16:18Speaker 01

  And now I feel bad for them.

• 16:20Neil deGrasse Tyson?

  No, there's surely no life on their surface, but many planets have heat sources within. Earth still does.

• 16:26Speaker 01

  Exactly.

• 16:26Neil deGrasse Tyson?

  The geologists, rather than calling it earth heat, call it geothermal sources.

• 16:30Speaker 01

  That's correct.

• 16:30Neil deGrasse Tyson?

  Cause they like bigger words, but it's earth heat, geothermal earth heat.

• 16:35Speaker 01

  Right.

• 16:35Neil deGrasse Tyson?

  Earth has heat. That's what gives us volcanoes and things. It has nothing to do with the sun. I can imagine one of these planets having life thriving deep within.

• 16:42Speaker 01

  Deep within the planet.

• 16:42Neil deGrasse Tyson?

  But they would never know a day of sunlight because they are not near a star. So. It has been suggested that there are more rogue planets in this galaxy than there are planets in orbit around stars. So that's a, that's a hypothesis that remains to be tested, but the models tell us that that is likely first. Second, what was, uh, was it the first part of his question?

• 17:03Speaker 01

  That was a.

• 17:04Neil deGrasse Tyson?

  So do we actually encounter Oh, do we encounter? Objects from another solar system? So. Since we can lose objects. Exactly. So we can lose them. Why won't we some come our way? Okay, space is vast and mostly empty. Right. So, so it, something has to come near enough to us to then plunge through our orbital, our planet. So, we look for comets which come from the outer reaches of the solar system. It's not likely to happen with an asteroid, but comets. Comets are cool. First, they, they, they render themselves visible with their beautiful coma and tail. Right. And coma is, by the way, Latin for hair. So it's Latin for hair.

• 17:46Neil deGrasse Tyson?

  And so that's how you get, that's where comet, that's where the comet coma gets its name. So you can see them much farther away than you could an asteroid. We've been looking for every comet whose orbit we can measure to see if its orbit is hyperbolic. Right. If you have a hyperbolic orbit, it means you have Coming back. No, no, no, no, no, no, no, no, no, no. You have a hyperbolic orbit, you have more energy than what the sun will contain for you. Which meant you were never bound to the sun to begin with. Okay. Which means you came from outer space. So it's the arc that goes around. The arc that goes around. The arc that goes around. When you speak hyperbolically, it means you're using language beyond what is necessary. Correct. A hyperbolic orbit, it has energy beyond what the sun can contain. We have yet to find a comet with hyperbolic velocity. You're listening to Cosmic Queries.

• 18:31Neil deGrasse Tyson?

  Neil deGrasse Tyson here with Chuck Nice. We'll be back in a moment.

• 18:53Neil deGrasse Tyson?

  We're back to StarTalk Cosmic Queries, which I like to think of as StarTalk after hours. But it's really not. It's just Yeah, exactly. It's just In some versions, in some versions of StarTalk, the questions will follow one of our broadcasts. I think that's why I think of it that way. But other ways you can get this is just us. Chuck Nice and I.

• 19:15Speaker 01

  That's right.

• 19:16Neil deGrasse Tyson?

  So, uh, we're talking about asteroids. These are questions called from the internet.

• 19:19Speaker 01

  Right.

• 19:20Neil deGrasse Tyson?

  Mm-hmm.

• 19:20Speaker 01

  So now, now, uh, if, before we go any further, cause I have a question. So you were talking about hyperbolic.

• 19:26Neil deGrasse Tyson?

  Oh, before the, before we broke. Yeah, before the break. Yeah, so, so some, we've been looking for a comet with a hyperbolic velocity. That would be sure evidence that it came from outside of our solar system.

• 19:36Speaker 01

  Right.

• 19:36Neil deGrasse Tyson?

  Cause a hyperbolic orbit means it has more energy than what is contained in orbit around the sun.

• 19:42Speaker 01

  So then, uh, what are the other, uh,

• 19:45Neil deGrasse Tyson?

  Kinds of orbit?

• 19:46Speaker 01

  Types of orbit?

• 19:47Neil deGrasse Tyson?

  Yeah, yeah. So if you, if you have exactly the energy to escape the sun, exactly the right amount, not hyperbolic energy.

• 19:55Speaker 01

  Right.

• 19:55Neil deGrasse Tyson?

  Where you're beyond it.

• 19:56Speaker 01

  Beyond that.

• 19:56Neil deGrasse Tyson?

  Right. Exactly energy, then you have a parabolic orbit.

• 19:59Speaker 01

  A parabolic?

• 20:00Neil deGrasse Tyson?

  Yeah, a, a, a parabola. You've all heard, you've all heard the word.

• 20:03Speaker 01

  So, so now what orbit would that be? That's what we see as?

• 20:06Neil deGrasse Tyson?

  No, no, no. It's open-ended and it would, so when it gets to infinity, it stops. Whereas a hyperbolic orbit, when it gets to infinity, it's still going.

• 20:15Speaker 01

  Right.

• 20:16Neil deGrasse Tyson?

  Right? I know that sounds crazy, but mathematically, that's how that plays out.

• 20:19Speaker 01

  Okay.

• 20:19Neil deGrasse Tyson?

  All right. So if you, now neither of those are bound to the sun, cause they're open-ended. So you, a bound orbit would be an ellipse.

• 20:28Speaker 01

  Okay.

• 20:28Neil deGrasse Tyson?

  And every comet we've ever had.

• 20:30Speaker 01

  Is elliptical.

• 20:30Neil deGrasse Tyson?

  Is elliptical. And some are extreme ellipses, damn near parabolas, but they're not parabolas and they're definitely not hyperbolas.

• 20:38Speaker 01

  Right, so.

• 20:39Neil deGrasse Tyson?

  And, and you keep tightening it up and the, the, and the other kind of orbit is, would be a perfect circle. And the, the object in the solar system that comes closest to that is Venus.

• 20:48Speaker 01

  Really?

• 20:48Neil deGrasse Tyson?

  Damn near perfect circle. Yeah. Very cool.

• 20:51Speaker 01

  Ah, see, I always liked Venus.

• 20:53Neil deGrasse Tyson?

  So we've never found an object, but the day we do, we are so, we are all over it. Oh, by the way, uh, some geologists have found what, uh, uh, uh, types of, uh, material within asteroids that they think came from another solar system, because the chemistry doesn't match the chemistry of other things in our solar system. But they themselves were not particles moving through. They collided with one of these, uh,

• 21:17Speaker 01

  Ah-ha.

• 21:17Neil deGrasse Tyson?

  These asteroids have been hanging around for billions of years. So they get embedded. You check it out. And they're called pre-solar grains. They've been around even before the solar system was invented.

• 21:26Speaker 01

  So they met.

• 21:27Neil deGrasse Tyson?

  They met.

• 21:28Speaker 01

  They met one of those hyperbolic.

• 21:29Neil deGrasse Tyson?

  I think I have that right. Yeah, they met a hyperbolic. Yeah, they said, where are you going?

• 21:33Speaker 01

  Right, right. Very cool.

• 21:36Neil deGrasse Tyson?

  Yeah.

• 21:36Speaker 01

  All right, well, here we go. Let's uh, let's move on to uh, Dalton Gory.

• 21:41Neil deGrasse Tyson?

  Mm-hmm.

• 21:43Speaker 01

  Does the earth have an asteroid season? As in a time during a period of our revolution around the sun in which we are more likely to have contact with asteroids.

• 21:55Neil deGrasse Tyson?

  Indeed, we do.

• 21:56Speaker 01

  Ah, way to go, Dalton.

• 21:58Neil deGrasse Tyson?

  Yeah, so every night you look up, if you have good eyes and good seeing conditions and the moon is not in the way, moonlight is not in the way.

• 22:05Speaker 01

  Right.

• 22:05Neil deGrasse Tyson?

  You'll see one shooting star every minute or two. That's the sort of the background level that's always there.

• 22:12Speaker 01

  Okay.

• 22:12Neil deGrasse Tyson?

  But as we go around the sun, there are streams of particles, streams of, of debris left over from comet orbits that had crossed our orbit.

• 22:23Speaker 01

  Uh-huh.

• 22:24Neil deGrasse Tyson?

  Cause as comet nears the sun, the ice evaporates, but the other crap that's in there mixed with the ice, it dislodges and then gets, and it sits in the orbit behind it and in front of it, and it spreads out, and that orbital path is there.

• 22:38Speaker 01

  Gotcha.

• 22:38Neil deGrasse Tyson?

  And when I say it's there, it, it continues to orbit the sun, but we plow through these orbital debris trails, and that's what we call meteor showers.

• 22:48Speaker 01

  Ah.

• 22:49Neil deGrasse Tyson?

  And that's why it only takes, it's a one night or two nights to get a meteor shower, cause given our speed and orbit around the sun, eighteen miles per second, that is, we plow through it, come out the other side, and we're clear and free again.

• 22:59Speaker 01

  So we're literally moving through, like a, like a little, like a little thunderstorm, like a little rain shower.

• 23:04Neil deGrasse Tyson?

  A little meteor shower, and in fact, if you come through this debris exactly right after the comet passed, there's more debris there than, than what is average, then you get a meteor storm.

• 23:15Speaker 01

  Ah.

• 23:15Neil deGrasse Tyson?

  Yeah, you get, oh, those are awesome, those, you get like, you know, a hundred meteors per minute in some cases. History tells us, there are woodcuts from the eighteen thirties and eighteen sixties, cause they didn't have, photography couldn't have captured it back then, that shows, it looks like one of these uh, chrysanthemum starbursts in a, in a, in a, in a fireworks display. So, so uh, so meteor storms happen and people freak out if you don't otherwise know what you're looking at.

• 23:41Speaker 01

  Yeah, that would have to freak you out, the gods are not pleased.

• 23:45Neil deGrasse Tyson?

  In fact, there's a story about Abe Lincoln. In 1833, there was one of these meteor storms, the Leonid Meteor Shower. You get a storm every 33 years, because the comet's orbit takes 33 years to go around the sun.

• 23:57Speaker 01

  Okay.

• 23:57Neil deGrasse Tyson?

  And so the lineup of, and its orbit crosses Earth.

• 23:59Speaker 01

  Right.

• 24:00Neil deGrasse Tyson?

  The lineup is such that we come right near the head of the comet every 33 years. You had one of these meteor storms in 1833. The local preacher, who is well-read in the Bible, of course, in Revelation, there's a part where it says, "At the end of days, stars will fall from the sky and land on Earth."

• 24:16Speaker 01

  Right.

• 24:17Neil deGrasse Tyson?

  Okay, so he sees this, he comes running, knocking on doors, goes into Abe's room, says, "The end of the world is near, repent." Abe Lincoln comes running out, he looks up, sees this beautiful shower, but notices that all the stars that he's familiar with were still there. The Big Dipper, Orion.

• 24:35Speaker 01

  Right.

• 24:35Neil deGrasse Tyson?

  So he went in, went back to sleep.

• 24:37Speaker 01

  And then he went and killed some vampires. Yo, that's cool.

• 24:41Neil deGrasse Tyson?

  So it helps to know a little astrophysic, I mean, he was well-read, better-read, apparently, than the preacher.

• 24:46Speaker 01

  So he, he had enough common sense to say, "Well, the stars are still there, this has gotta be something else."

• 24:50Neil deGrasse Tyson?

  Something else, and therefore they are not falling out of the sky.

• 24:53Speaker 01

  I see.

• 24:53Neil deGrasse Tyson?

  So that was a meteor storm.

• 24:54Speaker 01

  And just one more reason to love Abe Lincoln, that's all I can say.

• 24:58Neil deGrasse Tyson?

  Right, the man freed the slaves, and...

• 25:02Neil deGrasse Tyson?

  And like, snap, you know, there he is, he knows the night sky. Uh, we gotta take a break, we'll be back with more Cosmic Queries on Asteroids for StarTalk.

• 25:29Neil deGrasse Tyson?

  We're back to StarTalk, the Cosmic Queries edition.

• 25:31Speaker 01

  That's right. Absolutely.

• 25:34Neil deGrasse Tyson?

  Chuck, that's the voice of Chuck Nice you just heard. Chuck, give it to me.

• 25:36Speaker 01

  Yes.

• 25:37Neil deGrasse Tyson?

  By the way, you can find us on the web at starTalkRadio.net, where there are like archival shows and stuff. It's a, we've got blogs, it's a nice place to hang out, if you have nothing better to do.

• 25:45Speaker 01

  Yeah, and especially if you're first time here, then you can go back and see what you've missed.

• 25:49Neil deGrasse Tyson?

  See what you've missed, totally, and you've earned like a whole bunch of those, too.

• 25:51Speaker 01

  Yeah, exactly, that, well, you know, I love it, especially I love doing... Because I mean, where else can you connect Abraham Lincoln with meteor showers?

• 26:00Neil deGrasse Tyson?

  Okay.

• 26:00Speaker 01

  As we did.

• 26:01Neil deGrasse Tyson?

  As we did.

• 26:02Speaker 01

  Okay.

• 26:02Neil deGrasse Tyson?

  In the last second.

• 26:03Speaker 01

  Seriously, that's and it not be attenuated. That's what made it cool. All right, let's move on. Here we go. This is a.

• 26:08Neil deGrasse Tyson?

  Did you just use the word attenuated?

• 26:10Speaker 01

  Yes, I did.

• 26:10Neil deGrasse Tyson?

  Okay.

• 26:11Speaker 01

  Was that not good?

• 26:11Neil deGrasse Tyson?

  No, this is a SAT word. That's good. All right.

• 26:14Speaker 01

  Here we go. This is from Brendan McLennan. If we learn how to deflect an asteroid, doesn't that actually raise our chances of being struck by one? As there is a greater chance that a madman or rogue country or even us could use this technology as a doomsday weapon.

• 26:30Neil deGrasse Tyson?

  Oh, here's a man who's trying to think this through.

• 26:33Speaker 01

  He certainly is.

• 26:34Neil deGrasse Tyson?

  Unintended consequences.

• 26:36Speaker 01

  Absolutely.

• 26:36Neil deGrasse Tyson?

  So surely that's possible. But the energy required to direct an asteroid to a spot on the earth so that you can do damage there, when we already have nuclear weapons that can do the same thing.

• 26:51Speaker 01

  With pinpoint accuracy.

• 26:52Neil deGrasse Tyson?

  With pinpoint accuracy, render such an idea militarily pointless.

• 26:56Speaker 01

  Right. So in other words, it's possible, but you would be stupid to do it.

• 27:03Neil deGrasse Tyson?

  It would just be why? You got you just put a bomb in a plane and fly with just what are you doing? Right? I mean, what? So we already can destroy countries.

• 27:13Speaker 01

  Right.

• 27:13Neil deGrasse Tyson?

  We don't need to, you know, Hollywood scenarios to make that happen.

• 27:19Speaker 01

  Yeah, exactly. It's like it's kind of like having a gun and then manually inserting a bullet into someone.

• 27:27Speaker 01

  Hey, man, come here. Come here, man. I'm gonna push this right in your heart. That's what I'm gonna do.

• 27:33Neil deGrasse Tyson?

  That's exactly what this is.

• 27:34Speaker 01

  Okay. All right. Great.

• 27:37Neil deGrasse Tyson?

  All right, next question.

• 27:37Speaker 01

  Let's move on. Matt Kovak, uh, yes, Matt Kovak. Why would the government warn us?

• 27:42Neil deGrasse Tyson?

  You sure it's not Kovak?

• 27:44Speaker 01

  Yeah, it could be Kovak.

• 27:45Neil deGrasse Tyson?

  Yeah, Kovak.

• 27:46Speaker 01

  Why would the government warn us if an asteroid that was big enough to cause extinction were on its way for a direct impact with the earth and only the government knew it? And could not stop it or divert it.

• 27:59Neil deGrasse Tyson?

  I mean, why would they let us know?

• 28:00Speaker 01

  In other words, if this is gonna happen, there's no way in hell the government's gonna let us know, right?

• 28:05Neil deGrasse Tyson?

  You know why?

• 28:05Speaker 01

  Why?

• 28:06Neil deGrasse Tyson?

  Because the government isn't the ones discovering asteroids. People do it in their backyards with CCD cameras and their amateur telescopes and programs on the computer that calculates orbits for you. There is no such thing as a government cover-up because the sky is above everybody's head, not just Washington DC. So you cannot hide information when intelligent people are running the rest of the surface of the earth.

• 28:32Speaker 01

  Okay.

• 28:32Neil deGrasse Tyson?

  And, and any amateur astronomer who's talented in that trade can find an asteroid, and plot it up, and then tweet about it.

• 28:43Speaker 01

  Cool. So now that begs the question, this is a follow-up from Chuck Nice.

• 28:47Neil deGrasse Tyson?

  Oh, but so what, wait, so that means the scenario in the movie Deep Impact is essentially impossible. Where, where an asteroid is found and the government prevents anybody from knowing about it.

• 28:59Speaker 01

  Exactly.

• 28:59Neil deGrasse Tyson?

  They'd have to go in every amateur astronomer's backyard and say, "Yo."

• 29:02Speaker 01

  Alright, you just answered my follow-up question.

• 29:04Neil deGrasse Tyson?

  Oh, what's that?

• 29:05Speaker 01

  No, that was it. My follow-up question was, if there is an extinction-level asteroid about to hit the earth, would we be able to see it ourselves? Like, you know, basically, like, look up, there it is.

• 29:16Neil deGrasse Tyson?

  Yes, probably, but the bigger telescopes will see it farther away, so you get a longer baseline. But there will be a point when everyone who's got even a backyard telescope would be able to find it.

• 29:27Speaker 01

  Look up and say, "There it is."

• 29:28Neil deGrasse Tyson?

  Keep in mind that most comets are discovered by amateurs in their backyard, period.

• 29:32Speaker 01

  Okay, cool.

• 29:33Neil deGrasse Tyson?

  Yeah, and Armageddon, where the asteroid was Texas-sized?

• 29:37Speaker 01

  Right.

• 29:38Neil deGrasse Tyson?

  Excuse me? We would've discovered that in 1802! Come on now!

• 29:44Speaker 01

  Okay, alright, here we go.

• 29:46Neil deGrasse Tyson?

  We got a minute left in this segment.

• 29:49Speaker 01

  Alright, here we go. Brad Thor Rismiller. I love it.

• 29:53Neil deGrasse Tyson?

  The third, yes. He needs a Roman numeral.

• 29:56Speaker 01

  He certainly does. What amount of trajectory modification can be achieved via painting an asteroid white at various important distances? I gotta be honest, I have no frickin' idea what that means.

• 30:07Neil deGrasse Tyson?

  Okay, what he's saying is if you take an asteroid and paint it, because asteroids are dark, if you paint it white, it will reflect sunlight, and the bouncing sunlight off of that side will serve as a kind of mild propulsion to push it out of harm's way.

• 30:22Speaker 01

  What?

• 30:24Neil deGrasse Tyson?

  So, but the problem is, it's not a big push.

• 30:27Speaker 01

  Right.

• 30:27Neil deGrasse Tyson?

  It's a gentle push. You're using the pressure of photons, the particle of light bouncing off. Yes. And so when you, by the way, there's a version of the, remember that spinning thing on a bulb?

• 30:38Speaker 01

  Uh huh.

• 30:38Neil deGrasse Tyson?

  Most of that is because of convection of air around it, but if you completely evacuate it, light pressure will spin the thing around.

• 30:44Speaker 01

  Right.

• 30:44Neil deGrasse Tyson?

  So you do that for an asteroid, you need it early enough so that, that as low as that is, it'll still clear its way and, and clear it out of harm's way.

• 30:52Speaker 01

  Brilliant.

• 30:53Neil deGrasse Tyson?

  Brilliant. We will come back to StarTalk Cosmic Queries.

• 31:15Neil deGrasse Tyson?

  We're back in our final segment of StarTalk, the Cosmic Queries edition. I'm Neil deGrasse Tyson with Chuck Nice.

• 31:23Speaker 01

  That's right.

• 31:24Neil deGrasse Tyson?

  You're reading me these questions. I've never seen them before, but they've come to us on our website, solicited on the subject of asteroids.

• 31:30Speaker 01

  That is correct.

• 31:30Neil deGrasse Tyson?

  And we are in the final segment, which we're going to call the lightning round.

• 31:33Speaker 01

  The lightning round. So we're going to try and get as many questions as possible

• 31:36Neil deGrasse Tyson?

  As possible.

• 31:37Speaker 01

  in this period of time.

• 31:38Neil deGrasse Tyson?

  And we are inaugurating our very first bell for this purpose.

• 31:41Speaker 01

  So when you're done, you'll let me know by hitting the bell?

• 31:43Neil deGrasse Tyson?

  Go.

• 31:43Speaker 01

  Fantastic. This is from Brian Lefkowitz. Do we currently have the technology to track and deter asteroids from impacts like the one we saw in Russia recently?

• 31:52Neil deGrasse Tyson?

  No.

• 31:56Neil deGrasse Tyson?

  Next question.

• 31:57Speaker 01

  Next question.

• 31:58Neil deGrasse Tyson?

  By the way, that, that one was about the size of a third of a football field's length. It's 15 feet across. So we do not have the power or the, and the knowledge to track those. By the time they come, it's too late. Next.

• 32:10Speaker 01

  Here we go. I always read that the biggest threat when it comes to asteroids is that we can't always see them if they are coming from a certain angle. My question is, what percent of the area around the earth would this be the invisible zone? Or blind spots? Basically what he's asking is, does the earth have a blind spot?

• 32:27Neil deGrasse Tyson?

  Earth has a blind spot and it is towards the sun. The brightness of the sun washes out anything coming, so you could hide. Hide behind the sun and come at us, we would never know. Oh my gosh, you would never know. But it takes a long time to get from the sun to us. By then, we have a different angle around the sun. And perhaps we would then see this object against dark sky rather than against bright sky. Curiously, the brightness of the sun is our blind spot.

• 32:54Speaker 01

  Just like morning traffic. Wow.

• 32:57Neil deGrasse Tyson?

  As you drive into the rising sun, exactly. Next.

• 33:00Speaker 01

  How large would an asteroid be? And not wipe out most of the life on earth when it hits? Is it more location or size? This is the real question. Is it more location or size that would be the deciding factor? When it comes to wiping out life?

• 33:17Neil deGrasse Tyson?

  No, no. Just barely not wiping out life.

• 33:19Speaker 01

  Just barely not wiping out life, not wiping it out completely.

• 33:22Neil deGrasse Tyson?

  That asteroid is about a kilometer across, a little more than a half a mile. We've calculated this, that has enough energy to completely disrupt civilization. Where people are walking around with bows and arrows. And it is like caveman days all over again. It will not render us extinct. But the support structures, transportation, food distribution. Will be completely destroyed and it doesn't matter where it hits.

• 33:44Speaker 01

  Oh man, I hope it hits me because I don't want to be around afterwards. That sounded awful. Okay, what would the class of asteroid have much, uh, what class of asteroid? Would have as much effect on how powerful of an impact it will have on the earth? So, class CSM. I don't know what those are and that's what he wants to know.

• 34:07Neil deGrasse Tyson?

  Yeah, these are three different classes of asteroids. One would be mostly metals, one would be mostly rocky, another one would be what we call chondrites.

• 34:13Speaker 01

  Okay.

• 34:13Neil deGrasse Tyson?

  So what matters is not what is in them. What matters is simply how fast is the thing moving and what its mass is.

• 34:20Speaker 01

  Okay.

• 34:20Neil deGrasse Tyson?

  That's the good thing about physics of collisions. What the stuff is made of doesn't matter. By the way, the rocky ones are less likely to reach the ground, you'll get an air burst.

• 34:28Speaker 01

  Right.

• 34:29Neil deGrasse Tyson?

  Still bad.

• 34:30Speaker 01

  Right, because it sends a shockwave.

• 34:32Neil deGrasse Tyson?

  Hiroshima bomb was specifically designed to explode in air. To maximize its killing radius because if it hits the ground, it just makes a crater. And half your energy went into making a crater and not killing people. I didn't need them to get morbid on you, but that's so, doesn't matter what they're made of. It's all bad and it's just the kinetic energy, its velocity and its mass.

• 34:51Speaker 01

  Wow. Wow, that was not encouraging at all.

• 34:55Neil deGrasse Tyson?

  Okay, go.

• 34:57Speaker 01

  How likely is it that a comet, sorry, Matt, Eli, gotta give proper credit here. How likely is it that a comet will hit Mars in 2014? And the new Curiosity rover could land on the site after the impact for study?

• 35:12Neil deGrasse Tyson?

  Okay, so there is a comet that's coming a little bit dangerously close to Mars.

• 35:16Speaker 01

  Right.

• 35:16Neil deGrasse Tyson?

  All calculations show it's not likely going to hit Mars.

• 35:19Speaker 01

  Okay.

• 35:20Neil deGrasse Tyson?

  But if it did, it would be quite a show. And we're worried about trying to get Curiosity over to the impact site. Curiosity is in a, basically a zone, a crater, where it's gonna stay for its whole life.

• 35:29Speaker 01

  Okay.

• 35:30Neil deGrasse Tyson?

  It's not gonna like, it's not a globe tracker.

• 35:32Speaker 01

  Yeah.

• 35:33Neil deGrasse Tyson?

  But it would be kinda cool to go into that crater afterwards. We'd have to design another mission to do so.

• 35:38Speaker 01

  Okay, cool, cool.

• 35:39Neil deGrasse Tyson?

  Next.

• 35:40Speaker 01

  Let's move on to Philip Johnson, okay?

• 35:43Neil deGrasse Tyson?

  Not the architect.

• 35:44Speaker 01

  Not the architect. If Hollywood movies are to be believed, they would suggest that it's possible to land on a massive asteroid as an Armageddon. How big would the asteroid have to be before in theory you could land on it and walk its surface?

• 35:55Neil deGrasse Tyson?

  Okay, so asteroids have very low gravity. And so, no, you can't, you weigh a few ounces on these asteroids, maybe a pound.

• 36:02Speaker 01

  Okay.

• 36:03Neil deGrasse Tyson?

  Right? So that's not realistic to walk. Any muscular motion, you'd practically go into orbit.

• 36:08Speaker 01

  You're just gonna fly off.

• 36:09Neil deGrasse Tyson?

  You'd just fly off. So you really need grapple hooks or some sticky bottom shoes.

• 36:13Speaker 01

  Right.

• 36:14Neil deGrasse Tyson?

  To make this happen. So they're all low. All the gravity is low. So you just, everything has to be rethought. You're not gonna be depending on gravity.

• 36:21Speaker 01

  You're not taking a trip on the asteroid.

• 36:23Neil deGrasse Tyson?

  You're not just strolling, taking a walk in the park.

• 36:26Speaker 01

  Andrew Gefner wants to know, would you rather be a pirate or a ninja?

• 36:31Neil deGrasse Tyson?

  Oh, well, a pirate among the asteroids, because then you could take everybody's resources that they took. Yeah, but the best would be to be both, pirate and a ninja. Then you could like, "Arg!" and then kick their butt, you know?

• 36:44Speaker 01

  Ninja pirate gets my vote.

• 36:45Neil deGrasse Tyson?

  One question left, what do you got?

• 36:46Speaker 01

  Okay, this is Victor Ruiz. Marijuana, THC, is it possible to have a planet made of THC and therefore an asteroid made of THC?

• 36:57Neil deGrasse Tyson?

  I don't think so. But if there were such a planet and the people on it, they would still be talking about building their space program.

• 37:08Neil deGrasse Tyson?

  T H T, tetrahydrocannabinol. We've got to call it in to this StarTalk.

• 37:16Neil deGrasse Tyson?

  What am I, what's the show called? StarTalk Lightning Round. Chuck Nice, great to have you on the show. Always a pleasure. Brought to you in part by the National Science Foundation. This is Neil deGrasse Tyson. As always, bidding you to keep looking up.