StarTalk Radio - Cosmic Queries: Asteroids, Comets and Meteor Storms

Episode Date: May 5, 2013

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. Subscribe to SiriusXM Podcasts+ on Apple Podcasts to listen to new episodes ad-free and a whole week early.

Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now. This is StarTalk, the Cosmic Queries edition. I'm Neil deGrasse Tyson in studio with Chuck Nice. Hey, Neil. Hey, Chuck. Good to see you, man. This is not our first rodeo.

No, it is not. It is not. No, it is not. So what have we done? We've collected questions from our fan base, basically, those who like us on Facebook or Twitter. Or Google Plus. Google Plus. And they've been, we've solicited questions from them

on the topic of asteroids. Great video game back in the day, by the way, I just gotta say. You're dating yourself. Yeah, and that and Pong. You were totally 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. Okay. If you remember and if you're interested. I will keep that in mind. So you've got them all. So let's rock the house.

And let us remind the audience that these are questions that you have not seen. I've not seen, and I can't claim to. This is not stump Dr. Tyson. No, it's not. It's not. But I don't want to see them in advance, because it's more fun hearing them right up front. And we get to hear your truly spontaneous answer to these things. You hear me fumble over, and if I don't know an answer, I'll just say, go next.

Right, exactly. Right. And we'll end the hour with the lightning round. Actually, what's funny, I got a tweet that somebody retweeted from one of our former cosmic queries and it was the question um let me see if i can get it right uh can there be a time without gravity and or motion can there be time without motion and and that's what the question was answer neil colon no moving on it can't be the measurement of time without motion exactly there's of course time without

motion yeah all right so listen let's uh let's jump right into this and let's start off with uh deepak argawal is the person who sent this in how come we never know anyone with the names of people who ask questions i don't know man but i love it deepak argawal i want to hang out at a cocktail party with a guy named deepak argawal okay go on 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. Great question, because I'm in that group that he talked about. Are you ready? Please go right ahead. 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 words were not historically the same thing. They're not the same in the Bible. 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. 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. Gotcha. So the seven wanderers were Mercury, Venus, Mars, Jupiter, Saturn, the sun, and the moon. Gotcha. All of those moved against the background stars. And so some are easy. Sunday is sun.

Monday is moon. And Saturday is Saturn. Right? So those were planets originally. And no one knew anything about moons or asteroids. But comets were easy. Okay? We knew about comets.

And 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. Okay. So, 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.

That's it. 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 asteroids star-like so those are asteroids gotcha all right 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. All right, now, since Pluto's episode, poor Pluto, when we redefined planet to mean that which is round and has cleared out its orbit of miscellaneous debris, 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. We still get hit, but we cleaned up most of it. Pluto has not. 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 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 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 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 Ceres is big enough to be round. And so that's also a dwarf planet. Ceres was the goddess of harvest.

And Cereal comes from the name Ceres. Nice. I know. We're just rocking it. Wow. Okay, so now Minor Planet is basically all asteroids, and I think they include comets in that as well. Okay. So everything that does not have a round shape basically we call a Minor Planet.

You're going to call it a Minor Planet. A Minor Planet. That's right. And it's the catch-all drawer. It's the catch-all drawer. It's the catch-all drawer for the cosmos. Minor-drawer. It's the catch-drawer for the cosmos. Minor planet. So that was a great question, just helping.

Oh, there's also meteoroid, which is a tiny asteroid that is most of what you see as the shooting stars in the night sky. So the meteoroid becomes a meteor, becomes a meteorite. Gotcha. Okay, okay. So streaking across the sky, tiny little, it's a meteoroid, lands on the ground, it's still intact, meteorite. Meteorite. Usually the meteoroids vaporize, but that's who's counting.

Exactly. Okay. All right, cool. Man, that took almost the whole segment. It did. Holy cow. But guess what? It was good because now we have all of those definitions going forward.

So we can just rock the rest of it. Yeah. Okay. Because I'm serious. I really, I'm glad you did that because some of those definitions going forward. So we can just rock the rest of it. Yeah, because I'm serious. I really, I'm glad you did that because some of those things, I get confused. Even Chuck Nice gets confused. But no longer. 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? Okay, what's the reason behind some asteroids are incredibly metal rich and some are just big rocks? That is an awesome question. Too long in the next 12 seconds I can't answer it in 12 seconds Okay then Do you know what?

Cliffhanger 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 We're back to Cosmic Queries of StarTalk I'm Gildergrass Tyson with Chuck Nice Chuck tweeting at Chuck Nice Comic. That's correct, sir. I follow you. I follow you, too. You make me laugh every now and then. Oh, well, thank you. I think

I said that thank you too quickly. Yeah, you did. You made me laugh sometimes. Alright, so you're reading me questions that we've called from the internet. I've not seen them, but it's not stumped, Dr. Tyson. No, it isn't. It's fresher, I think, if I'd never heard them before. 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? That's a big, that's an excellent question. 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. Okay. 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 under cobalt nitrogen oxygen silicon iron all these elements are just mixed in the gas cloud and the heavy elements are not they're not so much but they're there right it's mostly hydrogen and helium right the sun gets is mostly hydrogen and helium it's got like that's where most of the hydrogen and helium went all right 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 going to sink to the bottom? The heaviest. The heavy stuff. Right. The iron, the platinum, the gold, the iridium, the osmium, the tungsten, it's all going to sink to the bottom. And the lighter stuff is going to float to the top, which is what it's called silicate. So, rocks.

Rocks, right. Compared to iron, rock is light, right? So true. So, those rise to the top and so now you have a body that has formed in space and then another object smashes it to smithereens and the smithereens are now asteroids right so now you have rocky asteroids made from the crust and mantle of that object because it came from that part from the rocky part came from the crust and mantle of that object. Because it came from that part, from the rocky part. 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 pre-sorted for our pleasure. Ah, yes. Yes. So the geologist calls that differentiation. Not to be confused with what you do in calculus. Right. Okay. Just so you know okay just so you know just so you know for those of you who are wondering because i already knew that yeah the jealous 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 is there with it. There you go. There you go, John. Heavy metal, it's not just a music. 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 and you find iron ore

that comes through. This is how we do our mining. There'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. And it's there. It's there on in mining but if we were at the core there would be no mining you just reach down pick up the iron and it's there it's there it's everywhere we're filthy with iron right do we mine rock no it's just there okay 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 ew that sounds like a disease or just coagulated debris field. Ew. That sounds like a disease.

You have coagulated debris fields. So we don't know what the mass of the asteroid belt might have been in the early solar system. 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. Really? Yes. Okay,. Really? Yes. Okay, you ready?

Yeah. Bring all the asteroid pieces together, and they will sum to about 5% of the mass of our moon. What? You heard what I said. You heard what I said. That's it? That's it.

That's it. What? Registered you to say that again? Yeah. That's it. That's it. 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 a zillion of them, probably a million asteroids, but they're very widely spread apart. There's a zillion of them, probably a million asteroids, but they're very widely spread apart. And in fact, the biggest asteroid, Ceres, is more massive than like the rest of all the asteroids combined. And Ceres is little, right?

So there's not much stuff out there. So to say this was once a mighty planet, I'm not ready to say that. Gotcha. There's not much there to begin with. If you put the moon out there and smashed it to smithereens, it would have an awesome, it would be a 20 times more awesome asteroid belt than what we have now. Than what we have right now.

Just our moon. God. Except the moon doesn't have much iron. Moon is an anomaly among large spherical objects. It should have an iron core given its size.

Right. Because 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, 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, which is what led to the impact theory hypothesis for the formation of the moon. Okay. That Earth formed, we already differentiated our stuff. Somebody else comes along and side swipes our crust.

Bang. And all of our crustal material becomes the moon. The moon. And that's why there's a good match between the moon and our crust and the moon has hardly any iron. See, and I thought you were going to say that's why there's a good match between the moon and our crust, and the moon has hardly any iron. See, and I thought you were going to 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. Yes. Okay, what else you got? Let's move on. Tim Pilgrim wants to know, would it be possible to use an asteroid as an interplanetary bus service? possible to use an asteroid as an interplanetary bus service. 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. But it so would not work. Okay. Why not? Because you have to catch up with the asteroid to step onto it. There you go.

And by the time you've done that- You could get to where you're going by- You're already in motion. So in other words, it's like driving a Ferrari to catch a bus. There you go. And by the time you've done that- You could get to where you're going by- You're already in motion. 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 don't need the asteroid. Right. You just- You just harness that power. You got your own spaceship. So it's a nice idea, but no. Maybe he's thinking of those cartoon things where it goes by and you reach onto it, and then your army elongates.

Right, and then you just get snatched along. You snap back, and then you're with it. But no, the physics prevents that from being a useful idea. But it sounds like a really cool idea because asteroids are going everywhere. Right. Yeah. Yeah. Well, listen, man, you get an A for creativity.

F for practicality. Okay. Yeah. But, okay, let's move on. What else you got? This is Alex Stevens. 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. Okay. So, that's an excellent question. First, our studies of the formation of solar systems tell us that our solar system might have had 20 or 30 planets when it was born. What? Where are they now?

That's what I want to know. They have escaped. What happens is 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. And now I feel bad for them. I know. No, there's surely no life on their surface, but many planets have heat sources within.

Earth still does. The geologists, rather than calling it Earth heat, call it geothermal sources. That's correct. Because they like bigger words. But it's Earth heat. Geothermal Earth heat. 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. Deep within the planet. 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 hypothesis that remains to be tested,

but the models tell us that that is likely. First. Second, was that the first part of his question? So do we actually encounter oh do we have objects from another solar system 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 render themselves visible with their beautiful coma and tail. And coma is, by the way, Latin for hair. So it's Latin for hair. And so that's where the way, Latin for hair. So it's Latin for hair. And so that's how you get, 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. It's 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, which means you came from outer space. So it's the arc that goes around. The arc that goes around. It's the arc that goes around.

If 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 can contain we have yet to find a comet with hyperbolic velocity you're listening to cosmic queries neil degrasse tyson here with chuck nice we'll be back in a moment 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 StarTalk with questions. In's just. It's just StarTalk. It's just StarTalk. In some versions of StarTalk, the questions will follow one of our broadcasts. Right. That's why I think of it that way. But other ways you can get this is just us. Chuck Nice and I. That's right.

So, we're talking about asteroids. These are questions called from the internet. Right. Mm-hmm. So, now, before we go any further, because I have a question. So, you were talking about hyperbolic. Oh, 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 right because a hyperbolic orbit means it has more energy

than what is contained in orbit around the sun. So then what are the other kinds of orbits? Types of orbits. Yeah, yeah. So if you have exactly the energy to escape the sun, exactly the right amount, not hyperbolic energy where you're beyond it. You're beyond that. Right. Exactly the energy, then you have a parabolic orbit. A parabola.

Yeah, a parabola. You've all heard the word. So now what orbit would that be? That's what we see as- No, no, no. It, a parabola. You've all heard the word. So now what orbit would that be? That's what we see as- No, no, no. It's open-ended. So when it gets to infinity, it stops. Whereas a hyperbolic orbit, when it gets to infinity, it's still going.

Right. I know that sounds crazy, but mathematically, that's how that plays out. Okay. All right. Now, neither of those are bound to the sun because they're open-ended. So, a bound orbit would be an ellipse. Okay. And every comet we've ever had is elliptical.

And some are extreme ellipses, damn near parabolas, but they're not parabolas and they're definitely not hyperbolas. Right. And you keep tightening it up and the other kind of orbit would be a perfect circle. And the object in the solar system that comes closest to that is Venus. Really? A damn near perfect circle. Yeah. Very cool.

See, I always like Venus. So we've never found an object, but the day we do, we are all over it. Oh, by the way, some geologists have found types of 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. 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 so they met they met they met one of those hyperbolic i have that right yeah they met a hyper yeah they said where you going right very cool yeah all right well here we go let's uh let's move on to uh dalton g. 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. Indeed we do. Oh.

Yeah. Way to go, Dalton. 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 right you'll see one shooting star every minute or two that's the sort of the background level that's always there okay 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 because 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. Gotcha. Well, when I say it's there, it continues to orbit the sun, but we plow through these orbital debris trails, and that's what we call meteor showers. Ah.

And that's why it only takes one night or two nights to get a meteor shower, because given our speed in orbit around the sun, 18 miles per second, that is, we plow through it, come out the other side, and we're clear and free again. So we're literally moving through it like a little thunderstorm, like a little rain shower. 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 what is average. Then you get a meteor storm.

Ah. Yeah. Oh, those are awesome. You get like 100 meteors per minute in some cases. History tells us there were woodcuts from the 1830s and 1860s because they didn't have photography couldn't have captured it back then that shows it looks like one of these 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 yeah that would have to freak you out the The gods are not pleased.

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

Still there. The Big Dipper, Orion. Right. So he went in, went back to sleep. And then he went and killed some vampires. No, that's cool. So it helps to know a little astrophysics. I mean, he was well-read, better read apparently than the preacher.

So he had enough common sense to say, well, the stars are still there. This has got to be something else. Something else. And therefore, they are not falling out of the sky. I see. So that was a meteor storm. And just one more reason to love Abe Lincoln. That's all I can say.

Right? The man freed the slaves and like, snap. You know, there he is. He knows the night sky. We've got to take a break. We'll be back with more Cosmic Queries on asteroids for StarTalk. We're back to StarTalk, the Cosmic Race Edition. That's right.

Absolutely. Chuck, that's the voice of Chuck Nice you just heard. Chuck, give it to me. Yes, here we go. By the way, you can find us on the web at StarTalkRadio.net, where there are archival shows and stuff. We've got blogs. It's a nice place to hang out if you have nothing better to do yeah and especially if you're first time here then you can go back and see what you've missed see what you've missed totally and you're in like a whole

bunch of those too yeah exactly that well you know i love it especially i love doing these because i mean where else can you connect uh abraham lincoln with uh meteor showers okay as we did as we did okay in the last segment and it not be attenuated that's what made it cool all right let's move on here we go uh this is uh did you just use the word attenuated yes i did okay why was that not good no this is sat word that's good all right 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.

Oh, here's a man who's trying to think this through. He certainly is. Unintended consequences. Absolutely. 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 with pinpoint accuracy pinpoint accuracy

renders such an idea militarily pointless right so in other words it's possible but you would be stupid to do it it would just be why you got you just put a bomb in a plane and fly with it. Just, what are you doing? Right? I mean, so we already can destroy countries. Right. We don't need to, you know, Hollywood scenarios to make that happen. Yeah, exactly.

It's kind of like having a gun and then manually inserting a bullet into someone. Hey, man, come here. Come here, man. I'm going to push this right in your heart. That's what I'm going to do. That's exactly what this is. Okay. All right.

Great. All right. Next question. Let's move on. Matt Kovach. Yes, Matt Kovach. Why would the government warn us? You sure it's not Kovach?

It could be Kovach. Yeah, Kovach. Why would the government warn us? You sure it's not Kovach? It could be Kovach. Yeah, Kovach. 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. I mean, why would they let us know? In other words, if this is going to happen, there's no way in hell the government's going to let us know, right? You know why? Why? 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 D.C.

So you cannot hide information when intelligent people are running the rest of the surface of the Earth. Okay. And any amateur astronomer who's talented in that trade can find a killer asteroid and plot it up and then tweet about it. Cool. So that begs the question, this is a follow-up from Chuck Nice. Oh, but so what, wait,

so that means the scenario in the movie Deep Impact is essentially impossible, where an asteroid is found and the government prevents anybody from knowing about it. Exactly. They'd have to go into every amateur astronomer's backyard and say, yo. All right, you just answered my follow-up question.

Oh, what's that? No, that was it. my follow-up question. Oh, what's that? 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.

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.

Look up and say, there it is. Keep in mind that most comets are discovered by amateurs in their backyard, period. Okay, cool. Yeah. And in Armageddon, where the asteroid was Texas-sized, excuse me? We would have discovered that in 1802. Come on now. Okay.

All right, here we go. We got a minute left in this segment all right here we go brad thor rissmiller i love it the third yes okay what he needs a roman numeral he certainly does what amount of trajectory modification can be achieved be a painting an asteroid white at various important distances. I got to be honest, I have no freaking idea what that means. 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. What? What? But the problem is it's not a big push. 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 spinning thing in a bulb. Most of that is because of convection of air around it. But if you completely evacuate it, light pressure will spin the thing around. Right. So you do that for an asteroid. You need it early enough so that as low as that is, it'll still clear its way and clear it out of harm's way.

Brilliant. Brilliant. We will come back to Star the Cosmic Queries edition. I'm Neil deGrasse Tyson with Chuck Nice. 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. That is correct. And we are in the final segment which we're going to call the lightning round. The lightning round.

So we're going to try and get as many questions as possible in this period of time. And we are inaugurating our very first bell for this purpose. So when you're done,

you'll let me know by hitting the bell. Go. 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? No. Next question. Next question. By the way, 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 knowledge to track those. By the time they come, it's too late. Too late. 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 spot? Basically, what he's asking is, does the Earth zone or blind spot is basically what he's asking

is does the earth have a blind spot earth has a blind spot and it is towards the sun the brightness of the sun washes out anything coming so you could 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. Just like morning traffic. Wow. Oh, as you drive into the rising sun.

Exactly. Next. 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? No, no. Just barely not wiping out life.

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

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, 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. Yeah, class C, S, M. I don't know what those are, and that's what he wants to know. 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. So, what matters is not what is in them, what matters is simply how fast is the thing moving and what its mass is. 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

Still bad Right Because it sends a shockwave 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 mean to get morbid on you But that's So it doesn't matter what they're made of it's all bad and it's just the kinetic energy it's velocity and it's mass wow wow that was not encouraging at all how likely is it that a comet sorry matt eli gotta give a 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? Okay. So, there is a comet that's coming a little bit dangerously close to Mars. Right. All calculations show it's not likely going to hit Mars. 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 basically a zone, a crater, where it's going to stay for its whole life. It's not a globe tracker. But it would be kind of cool to go into that crater afterwards. We'd have to design another mission to do so. Okay, cool, cool. Next. Let's move on to Philip Johnson.

Not the architect. Not the architect. Okay. Let's move on to Philip Johnson. Okay. Not the architect. 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?

Okay. So asteroids have very low gravity. And so, no, you can't. You weigh a few ounces on these asteroids, maybe a pound. Okay. Right? So that's not realistic to walk. Any muscular motion, you practically go into orbit.

You're just going to fly off. You just fly off. So you really need grapple hooks or some sticky bottom shoes 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 going to be depending on gravity. You're not going to be traveling.

You're not taking a trip on the asteroid. You're not just strolling, taking a walk in the park. Andrew Geffner wants to know, would you rather be a pirate or a ninja? 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, a pirate and a ninja. Then you could like, arg, and then kick their butt.

You know what I mean? Ninja pirate gets my vote. One question left. What do you got? Okay, this is Victor Ruelas. Marijuana, THC. Is it possible

to have a planet made of THC and therefore an asteroid made of THC? 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. Sure. THC, tetrahydrocannabinol. Oh, that's great. We've got to call it in to this Star Talk. What am I?

What's this show called? Star Talk 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.