Cosmic Queries – Asteroids and Comets

They could be transporters of life or harbingers of doom – Neil deGrasse Tyson answers fan-submitted questions on comets and asteroids with science author and cosmochemist Natalie Starkey, PhD, and first-time comic co-host Mark Normand. NOTE: StarTalk All-Access subscribers can watch or listen to this entire episode commercial-free here: https://www.startalkradio.net/all-access/cosmic-queries-asteroids-and-comets/ Illustration Credit: European Southern Observatory/M. Kornmesser.

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

• 0:00Neil deGrasse Tyson?

  From the American Museum of Natural History in New York City, and beaming out across all of space and time, this is StarTalk, where science and pop culture collide.

• 0:24Neil deGrasse Tyson?

  This is StarTalk. I'm your host, Neil deGrasse Tyson, your personal astrophysicist, and today is a cosmic queries edition of StarTalk. And I've got with me co-host Mark Norman. Mark?

• 0:39Speaker 01

  Nice.

• 0:39Neil deGrasse Tyson?

  The first timer.

• 0:40Speaker 01

  Hey, hey, big fan, happy to be here. Thank you.

• 0:43Neil deGrasse Tyson?

  Your local New Yorker?

• 0:44Speaker 01

  Local, got lost in the museum like an idiot.

• 0:46Neil deGrasse Tyson?

  If you have to get lost anywhere, let it be the American Museum of Natural History.

• 0:49Speaker 01

  That's true.

• 0:50Neil deGrasse Tyson?

  In the day.

• 0:51Speaker 01

  Yes, oh, that would be terrifying.

• 0:53Neil deGrasse Tyson?

  You don't want to get lost at night.

• 0:54Speaker 01

  No, sadly, I was using my Night at the Museum knowledge.

• 0:57Neil deGrasse Tyson?

  Oh.

• 0:58Speaker 01

  I've seen the movie.

• 1:00Neil deGrasse Tyson?

  Using your coordinate system from that movie.

• 1:03Speaker 01

  Yeah.

• 1:03Neil deGrasse Tyson?

  To avoid, uh, no, but you got here in one piece, which is excellent. Today's topic is comets and asteroids. And I know a little something about it, but I don't know as much as I should know about it to carry this episode alone. So we went in for backup.

• 1:19Speaker 01

  Nice.

• 1:20Neil deGrasse Tyson?

  Backup. And there's a good friend of ours who's been a guest before, Natalie Starkey. Natalie, welcome back to StarTalk.

• 1:28Natalie Starkey?

  Hi, Neil. Hi, Mark. It's great to be here. Thanks for having me.

• 1:31Neil deGrasse Tyson?

  We've got you online. You are in...

• 1:33Speaker 01

  Mexico?

• 1:34Neil deGrasse Tyson?

  No, Mexico. She's on Mars, actually. No, no, so we've got her, you're in the UK right now, is that correct?

• 1:41Natalie Starkey?

  Yes, yes, I am. I was over in California for about three years, living over there, and now I'm back in the UK, so I'm getting used to the rain again and the cold, and I'm very miserable.

• 1:51Neil deGrasse Tyson?

  We got spoiled that you were so accessible to us over those three years, forgetting that you're basically a UK person, so...

• 1:58Natalie Starkey?

  I am, yeah.

• 1:59Neil deGrasse Tyson?

  You're officially a science communicator. That's like a title that you carry for the Open University just outside of London, right?

• 2:08Natalie Starkey?

  Yes, that's correct, yes. I've been a scientific researcher for about ten or eleven years. And then I got into writing and I love communicating the science that I do. So yeah, I'm getting into it more seriously now. So I've sort of like, I've got a serious science background. I know quite a bit about comets and asteroids, so hopefully I can be of use today. I'm hoping, fingers crossed.

• 2:30Neil deGrasse Tyson?

  So we've got, and I happen to have, I think what is your latest book? Called Catching Stardust.

• 2:36Natalie Starkey?

  Yes.

• 2:36Neil deGrasse Tyson?

  Comets, Asteroids and the Birth of the Solar System. I have it in my lap.

• 2:39Natalie Starkey?

  I'm gonna hold it up for the camera for those people who are watching. I had to do a bit of product placement, you know.

• 2:46Neil deGrasse Tyson?

  Exactly, exactly. But you gotta come back one day and sign it.

• 2:49Natalie Starkey?

  Definitely.

• 2:50Neil deGrasse Tyson?

  So we called questions from our fanbase.

• 2:52Speaker 01

  Yes.

• 2:52Neil deGrasse Tyson?

  On this topic of comets and asteroids. And so let's, let's see what you got. Neither she nor I have seen these questions.

• 2:58Speaker 01

  Alright.

• 2:58Neil deGrasse Tyson?

  So let's check them out.

• 2:59Speaker 01

  Okay.

• 3:00Natalie Starkey?

  Kind of nerve wracking. I'm a bit, I'm a bit worried. I hate having my knowledge tested.

• 3:04Neil deGrasse Tyson?

  Yeah.

• 3:04Natalie Starkey?

  We'll see how it goes.

• 3:06Neil deGrasse Tyson?

  If you don't know, just say I have no fricking idea. Go on to the next question. Right, okay.

• 3:10Speaker 01

  Alright, these are pretty good. I've read a few and I'm gonna go handpick. Alright, this first one's from Kyle Ryan Toth. He's a Patreon member.

• 3:19Neil deGrasse Tyson?

  Patreon, we gotta serve them first, apparently, yeah.

• 3:21Speaker 01

  Exactly. Would it really be possible to hollow out an asteroid and use it as a starship?

• 3:29Neil deGrasse Tyson?

  Ooh.

• 3:29Speaker 01

  Cool.

• 3:30Neil deGrasse Tyson?

  Ooh, Natalie, how about that one?

• 3:32Natalie Starkey?

  Okay, so I'm gonna say no, straight off, just to be really boring. But actually, one of the reasons we couldn't really do this, well, with most asteroids anyways, that they're either just too hard, or they're just not made of the right stuff. So, you know, we've got some asteroids that are made completely of metal. So, I mean, trying to hollow that out would be almost impossible, you know. We've talked about, you know, mining these in the past, and we talked about them on the show quite a bit. And it's incredibly difficult to do that. So I think mining a pure metal asteroid would be hard. And then the others that are made of, you know, they could be slightly softer. We described some of them as a bit of a rubble pile, so they're kind of just... Rock that's not very well consolidated, not very well pushed together. So that would basically break up as soon as you try to start excavating it in any way.

• 4:18Natalie Starkey?

  So you'd have a better chance, maybe living on the surface. But I think even then, you know, there's no gravity essentially. So they're kind of hard beasts to work with. I don't think we're going to live inside one.

• 4:29Neil deGrasse Tyson?

  So they're very low gravity. They have some gravity, right?

• 4:31Natalie Starkey?

  They do, they do have a little bit. But basically you would need to be tethered onto the surface of one. If maybe we went to the largest asteroid in the asteroid belt, which is Ceres. It's about a thousand kilometers across.

• 4:43Speaker 01

  Wow.

• 4:44Natalie Starkey?

  So it's going to have a little bit of gravity. But if you jumped too high and you would probably just end up floating off into space. So it's not going to be a great environment to try and live on or in rather.

• 4:56Neil deGrasse Tyson?

  Yeah, so I think that the lesson there is just make your own damn spaceship. Live in that.

• 5:01Speaker 01

  Yeah, but could you get a rudder on there? I mean, could you steer? You know what I mean? I feel like you wouldn't get any, any directionality.

• 5:09Neil deGrasse Tyson?

  Oh, you mean if it's just a hollowed out orb? Yeah, you'd need some kind of retro rockets affixed to the side of it so that you can maneuver.

• 5:17Speaker 01

  Exactly.

• 5:17Neil deGrasse Tyson?

  Rather than just like a homeless shelter in, inside a, a shell.

• 5:22Speaker 01

  Right.

• 5:23Neil deGrasse Tyson?

  Yeah, I don't know what they were thinking of with that question.

• 5:25Speaker 01

  Yeah, yeah, I mean, it's a fun thought. All right, let me throw to this guy. He's an idiot.

• 5:31Neil deGrasse Tyson?

  Go for it.

• 5:31Speaker 01

  Kyle, you blew it. Nice job, Kyle. He's smoking weed. This is kids.

• 5:36Neil deGrasse Tyson?

  We just lost one Patreon member there.

• 5:38Speaker 01

  Okay, I'll cover him.

• 5:40Neil deGrasse Tyson?

  All right.

• 5:42Speaker 01

  This is from Michael Halterman. Can comets have different colors? Diversity. Maybe when the ingredients in organic molecules are different, can they spread molecules for the beginning of life?

• 5:56Natalie Starkey?

  Yeah, okay. So there's sort of two questions there. So the first bit was about the colors of them. And yeah, for sure, when we see comets in the night sky, they, they can glow different colors. And actually, green is a really common color in, when we look at these objects and for various reasons. And when we look at a comet or an asteroid, maybe in the night sky with a telescope, then they can glow green because of the oxygen that's in them. But actually, sometimes if you see a meteor coming through, so basically if you get a little bit of an asteroid break off in the space and then head to the earth and you see that as a fireball in the night sky. Sometimes they can glow green, and that's for a different reason. So that's some, because we have basically nickel, which is burning up. So I mentioned that we had these metal asteroids earlier.

• 6:41Natalie Starkey?

  And nickel is, is one of the metals that they have in them. And actually, when that burns up in the atmosphere, that glows green. So sometimes you see this kind of green streak with a meteor. You're quite lucky if you see it. I've never actually seen it. So, but I know people talk about it. And so that's the nickel kind of burning up. So, yes, they definitely have different colors. What was the second part of that question? I've forgotten already. This is not good.

• 7:00Neil deGrasse Tyson?

  No, no, you're correct. Life, whether the, the ingredients within the tail of a comet are, are the right ones to possibly spawn life.

• 7:09Natalie Starkey?

  Yeah, okay, definitely. So this has been quite a recent research finding, actually, that we discovered with some of the recent missions to comets. So in particular, the European Space Agency sent the Rosetta mission to go and land on the surface of a comet back in 2014 now. And they discovered that there was actually glycin, which is an amino acid within the comet. So we know there's basically these complex carbon molecules within them. And so there's every chance that, you know, they have the right ingredients for life. And this is why we sort of say, well, you know, in the past, we think Earth was bombarded by comets and asteroids from space. And so it's a plausible way that we could have brought life and water to Earth. Because we know that these objects contain a lot of these ingredients.

• 7:53Natalie Starkey?

  And we know that asteroids contain hundreds of amino acids. So, so these objects in space, they're very old, they're very what we call primitive. They're some of the most, the earliest things that formed in the solar system. But they contain all the ingredients that you need to basically build a planet and, and build life on that planet. So that, this is why I find them such fascinating objects, because they just, they have everything we need.

• 8:15Neil deGrasse Tyson?

  And that would mean that life, based on what you just said, life could be vastly more common in the universe than people might have previously suspected.

• 8:24Natalie Starkey?

  Yeah, so the problem is, there's a bit of a leap from going from just having the amino acids and the basic, you know, carbon compounds and the molecules to then getting life. Okay, so that's a massive leap because the problem is, we might have all these ingredients in space everywhere. In fact, they might be in every solar system we care to look at. But the problem is, it doesn't mean that we've got life because we need some very special conditions to let those ingredients become life. It isn't just a simple step, so.

• 8:51Neil deGrasse Tyson?

  We think they're special conditions, maybe they're common.

• 8:55Natalie Starkey?

  Well, this is very true. We have only so far observed life once, and that is on Earth. But it doesn't mean that in the hundreds of billions of galaxies that are out there on all the stars, that there isn't life somewhere else. We just haven't seen it yet. Now, obviously, we don't actually know, there's not other life in our own solar system. We just haven't seen it. But we're pretty sure it doesn't exist on the terrestrial planets, the ones that are near to, these are the rocky ones near to the sun, like Mercury, Venus and Mars. Maybe they had life in the past, we haven't discovered that yet. But there is a chance that there is life on some of these weird moons like Europa and Enceladus and things. So we're not sure yet, but there's a chance it could be. Because they've got a lot of the right ingredients for life. They've got liquid water, they've

• 9:38Natalie Starkey?

  got, basically, they're energetic bodies. They've got, they've got heat that they're losing, so they have all the energy that they could create life and, and help it, you know, get along and move along. So we just haven't found it there yet. We need to go and look. We need some missions to go and, and, and look at these places in more detail. But they're challenging environments to send spacecraft to. So that's one of our problems at the moment.

• 9:59Neil deGrasse Tyson?

  As Frankenstein's knew, Dr. Frankenstein, you can't just have the raw ingredients, you need energy. Right. And he had like that lightning bolt going through the electrodes on the, on the neck. Yes. See? That's all it takes.

• 10:16Speaker 01

  That's it. Wow. Well, that was well done.

• 10:18Neil deGrasse Tyson?

  Yo, thank you, Natalie.

• 10:19Speaker 01

  Natalie, killed it. All right, let's see. Um, well done. Uh, also nickel I didn't know about.

• 10:26Neil deGrasse Tyson?

  Oh, you didn't know about nickel?

• 10:27Speaker 01

  No, nickel, please.

• 10:29Neil deGrasse Tyson?

  You know who knows about nickel?

• 10:30Speaker 01

  No.

• 10:30Neil deGrasse Tyson?

  The Gucci brothers for the fireworks.

• 10:35Speaker 01

  Ah.

• 10:35Neil deGrasse Tyson?

  There's all these metals that get burned in fireworks that give you all the beautiful colors.

• 10:39Speaker 01

  Ah, I didn't know that.

• 10:40Neil deGrasse Tyson?

  Yeah.

• 10:40Speaker 01

  Wow.

• 10:41Neil deGrasse Tyson?

  Nickel, nickel, copper. Um, what else they have in there? Magnesium, I think. Natalie?

• 10:46Natalie Starkey?

  Yeah. Yeah, I think that's a good, yeah. So basically, it's a bit like doing that flame test. You might have done that in chemistry labs at school. Um, basically, it's the same principles. Each element burns with a different color, but basically this is the principles, yeah, of fireworks and everything. And what we see burning up from each is we could tell a lot about what that asteroid was made of if we can see it glowing. So, yeah, it's fascinating.

• 11:08Speaker 01

  All right. This is all news to me. Uh, here's another one from Ashley VGT. This is off Instagram.

• 11:16Neil deGrasse Tyson?

  Mm hmm.

• 11:17Speaker 01

  Uh, I've read that water did not originate on Earth, but instead was introduced by asteroids. But wouldn't the water evaporate away upon entering the atmosphere?

• 11:29Neil deGrasse Tyson?

  Ooh, burn up.

• 11:30Speaker 01

  Burn up.

• 11:31Neil deGrasse Tyson?

  Coming in. So what's up with that, Natalie?

• 11:34Natalie Starkey?

  So the whole water on Earth thing is, is definitely a big, open debate still. Um, scientists currently really don't have a good consensus on where our water came from. So there's, the problem is that if Earth started with all its water from the beginning. So our planet is about 4.5 billion years old. It was born out of this cloud of gas and dust really close to the sun. And, and we think that that early cloud contained water because if we go into interstellar space, where all our solar systems are made from, and they, sure enough, there is water out there. There's as ice, of course, because it's very cold. And now that gets kind of swept up into the forming star. And, and then all the planets are born out of the cloud of gas and dust that is around that star.

• 12:17Natalie Starkey?

  So, so there's water ice there that could then be contained within the planets that we form. But the problem is the very first few million slash billion years of Of a planet's infancy. It's incredibly hot. So it's basically just like a volcanic world. It really wouldn't be able to support a lot of water unless the water was sequestered away very deep within the planet, maybe, and it didn't evaporate at the surface. So we're not sure whether we could have, from the beginning, had our water or whether, sure enough, it would have all boiled off during that process and then we needed to bring it in later on. And we know we were bombarded by comets and asteroids about four billion years ago. We just have to look at the surface of the moon for that, actually, because you see that beautiful cratered surface of the moon.

• 13:01Natalie Starkey?

  And actually, we were hit by as many things as the moon was hit by, but we have this thing called plate tectonics, where our surface gets continually changing, updated and resurfaced. So we've lost all that evidence of all those craters, whereas the moons preserved them for us, so we know that we were hit in the past. And sure enough, those comets and asteroids contained water, some of them did anyway, not all of them. And they could, if they didn't, if they were large enough and they didn't evaporate and explode completely on re-entry through the atmosphere. And remember, our atmosphere was quite different back in the day. In fact, we might have had much, much of a thinner atmosphere that didn't slow them down as much, then potentially they could have brought a lot of water with them. But for us, trying to figure out where the water came from is very, very tricky because

• 13:45Natalie Starkey?

  we need to find out, you know, what the water looks like. And it's all mixed up now. We've got a mixture of all these different types of water. So if we want to measure it now, it's very complicated to try and figure out exactly where it came from. And all the comets are different, all the asteroids are different. So it's, we need to just go out there and measure more of these objects to then try and kind of piece this story together. But it's important because we want to understand why water's here. Why are we the only planet in our solar system with liquid water at the surface? It's a question that we really want to answer to understand where life came from as well.

• 14:15Neil deGrasse Tyson?

  So that was a yes.

• 14:19Natalie Starkey?

  It's one of my favorite subjects.

• 14:21Neil deGrasse Tyson?

  Okay. That was clear.

• 14:23Speaker 01

  Yeah. This is from Donny Huss, 1130 from Instagram. How much material do asteroids contain and how much are they worth? It's like a comedian.

• 14:34Neil deGrasse Tyson?

  Ooh. But let's sharpen that and say, of the metallic asteroids that have like metals we care about, can you estimate the value of them? And what does the value mean if they're out there versus if we brought them back to Earth and now they're just on Earth? Like value is just, value is a flexible thing in this, right?

• 14:56Natalie Starkey?

  Exactly. It's sort of like the diamond issue. Like, there's plenty of diamonds on Earth. We can mine plenty of them, and actually, a lot of them have been mined. But then, the diamond market is controlled, because if we released all those diamonds onto the market in one go, we'd flood the market and the price would drop. So, you know, the big diamond companies don't want that to happen, so they control that market. So, it's sort of the same thing with these asteroids. And one asteroid, okay, so there's a mission, a NASA mission, actually, going to an asteroid called 16 Psyche. And it's made purely of metal. We don't understand a lot about this asteroid, but it's quite large. And actually, the team that are planning to go to this asteroid have estimated that it's worth 10,000 quadrillion dollars. So, and that's just the iron within that.

• 15:38Natalie Starkey?

  So, basically, if they were to mine that whole asteroid, which would be impossible, because it's too large at the moment. We have no way of doing this at the moment. But if we were to be able to figure that out, and we brought all of that metal back to Earth, then sure enough, we're gonna flood the market, and it wouldn't just kill the metal market, it would kill the entire economy, because we wouldn't know what to do with all this. So, so they're worth a lot, but one of the issues is, we don't really know how to currently mine them. We don't know how we would extract that metal, and we don't necessarily want to bring it back to the planet, to be quite honest. We would like to bring some back, but actually, one of the reasons we want to mine in space is to be able to further explore space itself, so we could use these materials to actually, you know, make things. So, we might have a base on the moon where we actually manufactured materials and spacecraft,

• 16:20Natalie Starkey?

  or whatever we needed, and tools to actually go and explore further into space. So, there's a lot of economical questions around mining asteroids. And it's not just the science of how we do it, it's then looking at, you know, how it works and what we're gonna do with the materials that we get.

• 16:36Neil deGrasse Tyson?

  Mm-hmm. Cool. Rebuttal?

• 16:41Neil deGrasse Tyson?

  No, it's funny to just assign a value to something which, if you obtained it, would not have that value.

• 16:47Natalie Starkey?

  Exactly, yeah. It means nothing, really, but...

• 16:50Neil deGrasse Tyson?

  It's a weird, a weird economic fact. Right, right. Of this, so... I never would have thought you'd get money out of an asteroid. Yeah, well, plus, iron is not uncommon on Earth, right? So, I'm thinking, Natalie, that if you are gonna bring a metal from an asteroid to Earth, you bring a rare metal that we can use in ways that we can't do now. We can't... If you bring all that iron, is there something else you're going to do with iron that we're not already doing with iron?

• 17:19Natalie Starkey?

  No, so that's the thing. And the thing about these asteroids is, okay, they contain a lot of iron, but they contain maybe less than a percent of precious metals, things like platinum and gold and these metals that we use in technologies a lot in the modern day. Now, the thing is, they contain very low percentage of these, but that is still a lot more of these precious metals than we mine in any one year on our own planet. Because the thing is about the precious metals on Earth is that they're distributed throughout the crust of the Earth, and they're not very well concentrated. So to mine them, it takes a lot of effort. We have to dig up a lot of land in order to get those metals. Whereas if we just went to an asteroid, they're a lot easier to obtain. They're sort of concentrated in these objects. So these are the metals that are really important, because at the moment, we don't have a continued infinite supply.

• 18:04Natalie Starkey?

  So the kinds of industrial technologies we're looking, and you know, the advanced technologies we want to develop, are sort of held back a bit by the fact we don't have this infinite supply of some of these precious metals.

• 18:15Neil deGrasse Tyson?

  I think that's the key point, because it's not that you're just going to sell the metal and someone is going to then make jewelry out of it or something. There's industry that uses metal. Yes. And so it enables, no matter the price, it enables certain industries that wouldn't otherwise be enabled. Right. Perhaps we shouldn't think of it just as the metal as a pure thing, but the metal as an enabler of other ideas that engineers would pull out of the box. We've got to take a break. Mark, you're still here? Oh, yeah. Dr. Natalie Starkey, still there?

• 18:44Natalie Starkey?

  Yeah.

• 18:45Neil deGrasse Tyson?

  Out there, outside of London. Thanks for piping in. We are talking about asteroids and comets on this Cosmic Queries edition of StarTalk. We'll see you in a moment.

• 19:24Neil deGrasse Tyson?

  StarTalk, we're back, Cosmic Queries Edition. Mark Norman.

• 19:28Speaker 01

  Oh, yeah.

• 19:28Neil deGrasse Tyson?

  First timer.

• 19:29Speaker 01

  Oh, yeah. Love it here.

• 19:30Neil deGrasse Tyson?

  We're watching you.

• 19:31Speaker 01

  Yes.

• 19:32Neil deGrasse Tyson?

  Dr. Natalie Starkey, you still there with us?

• 19:35Natalie Starkey?

  Yes, I'm still there.

• 19:36Neil deGrasse Tyson?

  Excellent.

• 19:37Natalie Starkey?

  Yes.

• 19:37Neil deGrasse Tyson?

  Uh, expert on comets and asteroids, and that's our topic for the day.

• 19:41Speaker 01

  Yeah.

• 19:41Neil deGrasse Tyson?

  I know a little bit, and she knows a lot.

• 19:43Speaker 01

  Oh, yeah.

• 19:44Neil deGrasse Tyson?

  That's why we brought her on for this, for this episode.

• 19:47Natalie Starkey?

  It's just my pet subject.

• 19:50Neil deGrasse Tyson?

  You've got good questions on this?

• 19:51Speaker 01

  I got a million. Let me just, well, we talk about the nickel and the iron, if, if...

• 19:55Neil deGrasse Tyson?

  You got a question, too? You can do it, too.

• 19:57Speaker 01

  Okay, I just wonder if...

• 19:58Neil deGrasse Tyson?

  He's feeling it. He's feeling it.

• 19:59Speaker 01

  If asteroids contain diamonds, and we mined them, and we got the diamonds, and diamond prices went way down on Earth, would women still want them?

• 20:10Natalie Starkey?

  That's, yeah, I mean, the thing is, they do contain diamonds, um, but they're actually even more special than the diamonds we have on Earth. So they're actually sort of like interstellar diamonds. They're older than...

• 20:21Speaker 01

  Even better.

• 20:21Natalie Starkey?

  ...our solar system. So they, but they're tiny, this is the problem, so that, you know, they're kind of hard to find. So you probably wouldn't, you'd need a microscope to actually see it on your ring finger. Um, some, but, you know, you could tell everyone how special it was, and maybe they wouldn't care.

• 20:35Neil deGrasse Tyson?

  You can't see it, but it's interstellar, yeah.

• 20:37Speaker 01

  Yeah. All right. Here we are. Kimberly.io on Instagram, underscore Kimberly.io. How often does an asteroid come across our solar system?

• 20:50Natalie Starkey?

  We actually had, um, well, we don't really know if it's an asteroid or a comet, but there was an object recently called a mua mua, um, which is a Hawaiian word for basically kind of like foreign traveler or something. Um, and, and it's this object that appeared, and it was traveling very fast through our solar system, and some astronomers in, uh, in Hawaii saw it and found it first, and that's why it got a Hawaiian name. Um... And it was travelling so fast that they figured out it couldn't have come, it couldn't have originated within our solar system. So they actually decided that it must have come from another star system somewhere. They have no idea where exactly, they're still trying to figure that out. And but basically, it didn't, it was going so fast, it didn't get captured, you know, to our sun.

• 21:33Natalie Starkey?

  So it just kind of scooted by, and so it didn't enter into orbit into our solar system. And and this object has probably been travelling for, you know, potentially billions of years across interstellar space. And we don't know if we're the only solar system it's travelled through, but it's going on this massive long journey. Now, of course, this object could have actually collided with the planet and we wouldn't have seen it coming because it was going so quickly. And it was relatively small, it was very dark, and it's really, really hard to spot. But the thing we realise now is that we've spotted it because our technology has got so much better at trying to spot things in the night sky. It's actually probably happened before, probably we've had these visitors from other parts of, you know, the galaxy many times before, but we've just not seen them.

• 22:14Natalie Starkey?

  And sure enough, our own comets and asteroids could be out there visiting other star systems. And it's just something that happens during the process of forming a star and the planets around it that it's a little bit chaotic. And so comets and asteroids are essentially the bits and pieces left over that didn't become a planet. And sometimes, because they're small, they can get ejected out of the solar system or they get thrown into the sun and they end in a fiery death. But some of them get thrown out and and they just, you know, end up leaving the sun's gravity and and they go off into space. And then there's nothing stopping them, they're going to keep going. So so, yeah, it's really cool that we've got these objects. If we can start to identify more of them in the future and actually look for them, then we might also launch a mission to go and maybe sample one one day, which would be amazing.

• 22:59Natalie Starkey?

  Because we'll find out about the chemistry of another star system, which is something that I would be really interested in. And but, yeah, at the moment, we've only seen one and it's kind of gone now, it's exiting the solar system and it's going on its merry way into the abyss.

• 23:14Neil deGrasse Tyson?

  Wow. It's merry way into the abyss.

• 23:17Speaker 01

  That was beautiful, poetic.

• 23:18Neil deGrasse Tyson?

  I looked up Hamuamua, I think it means scout, like a first

• 23:21Natalie Starkey?

  Scout, yeah.

• 23:22Neil deGrasse Tyson?

  first journey person onto a new land, into a new place. A scout.

• 23:27Natalie Starkey?

  Yeah. It's a nice name, I like it.

• 23:29Neil deGrasse Tyson?

  Yeah, it is, it is.

• 23:30Speaker 01

  It is. Quick question, may not be answerable from Paul Pimenta on Facebook. Can we track where asteroids came from, specifically where they originated?

• 23:40Natalie Starkey?

  Yeah, yeah, definitely. So, actually, I mean, it's even better than that. Sometimes we get a meteorite that ends up on the planet. So this is just a rock from space that will usually come from an asteroid, or it can come from another planet. If we've seen that coming through the night sky and burning up through the atmosphere, then there's lots of, basically, camera networks out there now. And one of them's in the deep Australian outback. And they just basically have cameras set on the night sky to register these objects as they're coming in. And what they're trying to do is figure out an exact trajectory for them so that they can basically backtrack that with some amazing math and actually figure out where that object originated

• 24:22Natalie Starkey?

  and try and track it back to the asteroid belt itself. We can sort of check our calculations in a certain way by analyzing the chemistry of those rocks. So we can go and pick up that rock, because basically they know where it's landed because they've got that trajectory coming in on the cameras. They can go and pick that rock, analyze it in the lab, and compare it to what we know about the objects in the asteroid belt already. So, yes, it's actually possible. It's very complicated work, and we're making much more progress with it in probably the last decade or so. But yeah, we can definitely start to figure out. And we also know if it came from another planet. That's much easier to work out, actually, if it came from another planet than any old particular asteroid, because there's kind of billions of them out there. So it is tricky.

• 25:03Neil deGrasse Tyson?

  Billions of asteroids, but many fewer planets.

• 25:05Natalie Starkey?

  Yeah, there aren't too many planets. But there's probably like maybe 2 billion asteroids of over a kilometer in the asteroid belt. So there's an awful lot of them, and there's millions more smaller ones. So there are a lot of objects out there. But a lot of them, as I said, they're in these groups, they're in families. They're all different. There are groups that share similarities in where they were made and what they contain.

• 25:27Speaker 01

  It's like a 23andMe for an asteroid.

• 25:29Neil deGrasse Tyson?

  There it is.

• 25:30Speaker 01

  Uh-huh, so you meet an asteroid, he goes, "I'm Jewish."

• 25:32Neil deGrasse Tyson?

  Yeah.

• 25:33Speaker 01

  Who knew?

• 25:36Speaker 01

  All right. Uh, how large, this is from Renee Douglas Patreon, listen up. How large does a captured asteroid need to be in order to be called a moon? And can a comet also be captured?

• 25:51Natalie Starkey?

  Um, yeah, so the first part, I mean, in fact, it depends what you class as a moon, really, because some of the asteroids themselves have moons around them. And we've actually started to discover, I think we've found about 200 moons around asteroids now. So these are just small objects orbiting and basically attached to that asteroid in some way. They're, they're associated with it. And now the thing about the asteroids themselves is that even the largest asteroid we know of, which is Sarah's, is only about a quarter the size of our moon. So even the biggest one, and even if you pack them all together, so you take all the asteroids in the asteroid belt and put them all together in one blob, and they would only be about 4% of the mass of the moon.

• 26:35Natalie Starkey?

  So there's a lot of them out there, but they're just not very big. So if you wanted to capture an asteroid, well, you wouldn't be capturing one of the largest ones. And because that's sort of like, you know, thousand, well, hundreds of kilometers in diameter. So they're just too large to capture. When NASA have actually done some studies looking at potentially capturing an asteroid with sort of a bag or something, it sounds kind of crazy, but that's literally what they're sort of planning, or a scoop. And, and they're looking at something around 40 meters. And so it's not going to be particularly massive and it's not going to pose a problem to Earth if it goes very wrong, although that would still be an issue if that collided with the planet. So, so yeah, in terms of capturing them, you wouldn't capture something really massive.

• 27:17Natalie Starkey?

  Because you, I mean, if it went wrong, you'd be really in trouble if that collided with Earth.

• 27:22Speaker 01

  Wow. This is all, how have we not had more of that? Why, I mean, I don't know anything and I'm on Molly right now, but why don't we get hit by more asteroids and realize it and feel it?

• 27:33Neil deGrasse Tyson?

  Well, we do get hit.

• 27:34Speaker 01

  Okay.

• 27:34Neil deGrasse Tyson?

  Earth plows through, Natalie, correct me if I'm wrong, several hundred tons of meteor dust a day.

• 27:41Speaker 01

  Wow.

• 27:41Neil deGrasse Tyson?

  Descend on Earth, just by plowing through interplanetary space.

• 27:45Speaker 01

  And does it make a dent?

• 27:47Neil deGrasse Tyson?

  No, most of it just settles as dust because it lost all its energy coming through the atmosphere, but it's big enough that it'll just plow right through.

• 27:54Natalie Starkey?

  Yeah, there's like a size relationship, an inverse relationship. So the bigger the asteroid that's heading for the planet or it's gonna come through the atmosphere, the less frequently it hits. So the really small pieces of dust, they're literally raining down all the time and they're called micrometeorites or basically stardust. And then if you go to the larger objects, like the ones that killed off the dinosaurs, for example, then they don't hit very frequently. You know, every 10,000, maybe 1 million years or more, probably more in fact for ones that size. We had an event in Russia back in 2013. It was called Chelyabinsk and it was about a 20-meter asteroid. And so it's fairly large, I guess, kind of like a double-decker bus. And that didn't actually kill anybody,

• 28:39Natalie Starkey?

  but it did cause quite a lot of damage in the region and it had this big sonic boom as it came through the atmosphere. And actually it blew windows and everything in Chelyabinsk's town. And so, and we didn't know that was coming because it was actually quite small. We didn't, we didn't see it. We hadn't spotted it before it arrived. So, you know, yes, they happen. And obviously if that had hit central London, I'm pretty close to central London, that's about 60 miles across, maybe if you take Greater London into account. And actually that would be quite an issue if that had landed in the center of London. So it just, it's sort of lucky that most of the planet is sort of empty. And a lot of these asteroids tend to land in the ocean, so we don't see them and they don't cause us any harm. But yeah, they do hit all the time and just the larger ones not as often.

• 29:23Speaker 01

  Well, if you're gonna hit somewhere, I think Russia's the place. Yeah, come on.

• 29:27Neil deGrasse Tyson?

  Is that a political statement or geographic statement?

• 29:30Speaker 01

  Wow, I don't know anything about collusion.

• 29:33Neil deGrasse Tyson?

  It's the country with the largest landmass.

• 29:35Speaker 01

  Good, that's what I was saying.

• 29:37Neil deGrasse Tyson?

  So it's gonna get more asteroids and more comet collisions.

• 29:40Natalie Starkey?

  And a lot of it is empty, so that's good.

• 29:43Speaker 01

  But that's what they get for conquering. You conquer, you gotta realize, hey, you're gonna hit more asteroids.

• 29:47Neil deGrasse Tyson?

  There you go.

• 29:48Speaker 01

  Hits. Alright.

• 29:51Neil deGrasse Tyson?

  What else you get?

• 29:51Speaker 01

  Here we go, Natalie. This is from Frank Kane, Patreon member out of Orlando, Florida. Is there a really clear distinction between comets and asteroids? I mean, comets generally have some rock in them and asteroids have a lot of frozen gas in them, right? Where do we draw the line?

• 30:10Neil deGrasse Tyson?

  Ooh, very good.

• 30:11Natalie Starkey?

  Yeah, the other way around. So the asteroids are kind of the rocky, hard, metallic ones, classically. And then the comets are sort of the icy, dusty, dusty snowballs, or whatever you want to call them. But yeah, this sort of works. It's a pretty, like, old distinction that we always fall back on. But it's a very classical view of these objects. And actually, what we're finding as we go and look at more and more of them is that we've got a lot of asteroids that can contain quite a lot of water ice and other ices, like methane and things. And we have some comets that are completely dry. Because, for example, if they've been around the sun a lot of times, and they've been basically having their volatile ices burnt off all the time, then they're gonna be dry and they sort of look therefore like an asteroid.

• 30:56Natalie Starkey?

  So there's almost like a continuum, we think. Potentially, there's a continuum of compositions. We've got some things that definitely look like this classical asteroid, some things that definitely look like a comet that's very icy, and then a lot of material in between. And at the moment, we're still trying to piece together that story of basically where these objects formed and therefore what they're then made of today. And they've also been affected by what they've gone through in that 4.6 billion year history since they formed. So yeah, basically, we have that distinction, but it doesn't always work.

• 31:28Neil deGrasse Tyson?

  But we have yet to see a metallic comet.

• 31:30Natalie Starkey?

  Uh, true, but they do, yeah, but yeah, that's very true. We haven't, I mean, if you had a purely metal uh, objects out there, then it's definitely an asteroid. In fact, you know, this sixteen psyche asteroid that they want to go and look at, they think could be the center of a planet um, that was kind of blown to pieces at some point in the past um, when a lot, it might maybe collided with another asteroid. So it had basically in the earth, we've got this metallic core um, and that's what happens to these, the large objects in the solar system, they differentiate. So they're a big ball of magma and then the heavy material in that magma, the metal falls to the middle of the planet and the lighter stuff is on the outside. So if they experience an impact, all of this, what we call the crust and the mantle, which is the lighter stuff on the planet,

• 32:13Natalie Starkey?

  it gets kind of blown off the surface and you get left with this solid core, which is very hard to break up. So that's what we think, that's one theory of what this asteroid could be. So we can study it, actually look at the core of a planet, which is incredibly hard to do because we can't drill to the core of a planet. So these objects are really valuable scientifically for that reason.

• 32:32Speaker 01

  Oh, wow, man. How come, could we film them and watch them hit each other? I feel like that'd be a great pay-per-view.

• 32:39Neil deGrasse Tyson?

  Be cool, very cool pay-per-view.

• 32:41Speaker 01

  You could bet on them, like with the mob. You know, I got Haley.

• 32:46Neil deGrasse Tyson?

  We did, we did have a collision where there was a comet that was predicted to, and of course, successfully collided with, because it was predicted to do so, uh, the planet Jupiter.

• 32:55Speaker 01

  Wow.

• 32:56Neil deGrasse Tyson?

  And we caught it on Hubble telescope and everything.

• 32:57Speaker 01

  Hey.

• 32:58Neil deGrasse Tyson?

  Oh, it was, it was amazing.

• 33:00Speaker 01

  Send me the link.

• 33:01Neil deGrasse Tyson?

  It was amazing.

• 33:02Speaker 01

  All right, now we're talking.

• 33:03Neil deGrasse Tyson?

  And that was a comet that got ripped apart into multiple pieces, so it was like a train of cars uh, coming in, one after another. And they didn't all hit the same spot at Jupiter, you know why?

• 33:13Speaker 01

  Jupiter's big?

• 33:14Neil deGrasse Tyson?

  No, Jupiter rotates.

• 33:15Speaker 01

  Ah.

• 33:16Neil deGrasse Tyson?

  So it would rotate a fresh bit of its surface into view, that next piece would hit there. So by the time everybody hit, there was this line of impact scars in the atmosphere of Jupiter. It was beautiful, it was beautiful.

• 33:28Speaker 01

  Beautiful?

• 33:29Neil deGrasse Tyson?

  Beautiful.

• 33:29Speaker 01

  I love it, but how did it, ah, I just don't get why it would not burn up in the atmosphere or all that?

• 33:35Neil deGrasse Tyson?

  We're seeing, we're seeing the residue of that collision.

• 33:38Speaker 01

  I see.

• 33:38Neil deGrasse Tyson?

  Well, the energy. Would vaporize the the volatiles and well, it would it would also vaporize the rocks too, wouldn't it Natalie? There's a lot of energy.

• 33:47Natalie Starkey?

  Yeah, it's yeah, definitely. It sort of depends. It really just sort of depends what that thing is made of. So as I said, if we just had a purely kind of fluffy comet that was very icy. So if you imagine just taking a snowball and adding a bit of dirt to it and then compacting it together a little bit. If that, you know, came through our atmosphere or an atmosphere of any planet, it almost certainly would break up very high up and and really not cause any damage. It wouldn't get to the surface. But as I said, this this sort of continuum of composition. So some of these comments are a bit more rocky. So actually, the more rocky and the more metal components that an object contains, the more likely is to survive that impact. Metal could be stopped at a very high temperature before it's going to melt or explode. So so this is why it's hard to predict what's going to happen. So actually, being able to see that one hitting Jupiter was very informative

• 34:31Natalie Starkey?

  because we can actually try and figure out what it was made of and by the way that it reacted to to Jupiter's atmosphere. So it's the same when they are, you know, heading to Earth. If we think one's coming for us, then we really want to understand what it's made of and if it's actually going to pose any risk to us. Because surely enough, you know, if it was just made of ice, probably it's not going to be very harmful, even if it's enormous, it's probably not going to do us any harm. So so yeah, this is why we want to understand them in more detail and understand their composition and and their structure as well.

• 35:01Neil deGrasse Tyson?

  So we got to take a break. We'll be back for our third of three segments of Cosmic Queries Asteroids and Comets Edition with Dr. Natalie Stark. When we return.

• 35:23Speaker 03

  The future of space and the secrets of our planet revealed.

• 35:32Speaker 03

  This is StarTalk.

• 35:45Neil deGrasse Tyson?

  StarTalk, we're back. Cosmic Queries, Asteroids and Comets Edition with our friend and colleague Natalie Starkey. Natalie, phoning in from London, outside of London. We miss you in the States, huh? You were here for three years and then you just left us.

• 36:03Natalie Starkey?

  I know, I know, I miss California as well, but it's really far from home. So it's quite nice to be back in the rain. Quite enjoying it.

• 36:11Neil deGrasse Tyson?

  Said no one ever.

• 36:13Speaker 01

  She didn't leave us, she brexited.

• 36:16Neil deGrasse Tyson?

  Brexited, yes, yes.

• 36:17Natalie Starkey?

  No, I didn't mention that.

• 36:19Speaker 01

  Oh, sorry, sorry.

• 36:20Neil deGrasse Tyson?

  So Mark, my co-host for today, first timer, what do you have for us?

• 36:24Speaker 01

  Here we go.

• 36:25Neil deGrasse Tyson?

  Let's go.

• 36:25Speaker 01

  Voidwalker92 off Instagram. Are there any asteroids with their own natural satellites currently known? If so, how common or uncommon is this? And how does the dynamic effect traffic, tracking and understanding trajectory of the asteroid?

• 36:42Neil deGrasse Tyson?

  Oh, nice.

• 36:43Speaker 01

  Does that make sense?

• 36:44Neil deGrasse Tyson?

  Because we addressed a little bit of that earlier.

• 36:45Natalie Starkey?

  We definitely know that quite a lot of asteroids have moons, so natural satellites around them. And it's probably other bits of material of that same asteroid, but we're not sure because we haven't studied them in detail. One of the problems is that we can't actually see them very easily because the asteroids themselves are small and therefore their moons around them are even smaller. So we found about, I think it's over 200 moons around asteroids now. So we definitely know they're there. We want to study them in more detail because it will tell us more about that object itself and how that object formed.

• 37:14Neil deGrasse Tyson?

  Do you think those asteroid, do you think those moons dislodged from the asteroid itself to become a moon?

• 37:19Natalie Starkey?

  It's one option, or it could be that they captured them. Like, so some of the moons that we see around planets are either captured moons, so they're formed somewhere else in the solar system to that planet. And then basically that planet was large and so its gravity attracted other objects to it. And our own moon, for example, didn't form in that way. It formed from the Earth itself during a massive collision about four and a half billion years ago. And it basically threw off a bit of our own planet and then it coalesced into a moon and it was then, you know, trapped with the Earth. So there's different ways to form them, but we need to study more of them to figure out exactly how they formed.

• 37:54Neil deGrasse Tyson?

  All right. Next question.

• 37:56Speaker 01

  Well said, well said. Richard Stenhouse from Facebook. Hi guys, love the show. Bit of a kiss ass. I've been listening on Spotify since September 2018 whilst I'm at work. And I'm as far back as season two, can't get enough. Geez, this guy's like a regular Natalie. Get to it. Anyway, my question is, is there a point between stars where comets or asteroids are under no influence of gravity at all? And if they somehow lost momentum, would they hang in that space till the end of time? From North Wales, UK.

• 38:32Neil deGrasse Tyson?

  I love it. Love the question.

• 38:34Natalie Starkey?

  That's a great question. Oh my goodness, because I actually only found out recently myself that some of the comets, like that are in our Oort Cloud, which is the cloud of material that's outside of our, it kind of surrounds our solar system. So everything in our solar system is on a plane, it's on a disk, all the planets and all the comets and all the asteroids. And then we've got this Oort Cloud around us, which is all these icy objects of which we actually have never really seen any of them because they're so far away. And some of them on the edge of that Oort Cloud are so far away that they're almost not gravitationally bound to our own sun. And they're almost closer to the next star system. So sure enough, I don't know what happens at that point. I mean, I guess maybe some really clever astrophysicists maybe figure out what is happening

• 39:19Natalie Starkey?

  to those objects out there. But yeah, they could easily be perturbed. We would say they might be pushed around by the gravity of another star system and then either thrown out of our solar system completely or pushed in so that they actually come in and visit the sun and the inner solar system. But that's a great question.

• 39:36Neil deGrasse Tyson?

  Yeah, they're susceptible. Plus, we, the sun, the planets and everything, the family, we're all orbiting the center of the galaxy, among other stars. So even if you have a precariously positioned comet at the edge of this Oort Cloud and it doesn't have a gravitational allegiance. Eventually it will, because we're moving past other stars. Somebody's gonna snatch it.

• 40:00Speaker 01

  Yes.

• 40:01Neil deGrasse Tyson?

  And, or perturb it and have it descend back down into our star. So, so yeah, the things are always in motion. And if you're without allegiance, that wouldn't be for long.

• 40:11Speaker 01

  Mm-hmm. I'm so jealous.

• 40:14Neil deGrasse Tyson?

  And just to be clear, Oort is named for a guy named Jan Oort, who was a Dutch astronomer of mid-century, mid-20th century astronomer, who first proposed the existence of this reservoir of comets.

• 40:24Speaker 01

  Was he persecuted?

• 40:26Natalie Starkey?

  It was all theoretical, like you had no idea it was there. And it's still not really proven as such, but, um, because we've not really seen it. So it's just so far away, we'll never get there. And, you know, even if there's a spaceship out there now, like Voyager, they are not gonna get there for tens of thousands of years. Um, so yeah, it's a tricky one.

• 40:44Speaker 01

  Could we get a GoPro on one?

• 40:46Neil deGrasse Tyson?

  I know, you think?

• 40:47Speaker 01

  Why not?

• 40:47Neil deGrasse Tyson?

  Plus, this was mid-20th century, you asked if he was persecuted for suggesting this.

• 40:51Speaker 01

  Oh, well, mid, oh, sorry.

• 40:53Neil deGrasse Tyson?

  This is relatively modern times, right? The 1950s, we're not persecuting, not for that at least.

• 40:59Speaker 01

  They were very religious then.

• 41:00Neil deGrasse Tyson?

  Right, right.

• 41:01Speaker 01

  You don't wanna mess with that. All right. Uh, here we go. Brett LaRue, also Patreon. If we were to mine a significant amount of a comet, would this change its orbit? And if so, how could we be sure this would not set into motion future collisions that would result in a major Earth impact?

• 41:22Neil deGrasse Tyson?

  Ooh, ooh. Let me generalize that question. As we start poking around with asteroids, landing on them, uh, mining them, what risk does that pose to taking what was previously a safe orbit and turning it into an Earth-crossing orbit that could then kill us?

• 41:40Natalie Starkey?

  Yeah, it's, it's a huge risk, it is a huge risk. But this is why, um, the people that are looking at doing it are probably looking at focusing on the smaller asteroids or comets, if they want to look at comets, but it's generally asteroids we're talking about at the moment. And because then if they were to dislodge it onto an orbit that was then a hazardous one for our planet, then it hopefully would burn up in the atmosphere and not cause us any issue. But in terms of mining them, we probably wouldn't just go- Those them and mine them, we'd want to drag them somewhere to what we would consider a safe orbit. So this might be near the moon, where basically you can just kind of dump the stuff and it just sort of sits there. It's this gravitational sweet spot where the thing, basically if it's a small enough object, it's not going to go anywhere. And then what you could do is have a base on the moon and go back and forth to that object and mine it gradually.

• 42:25Natalie Starkey?

  So you basically just want to get it somewhere safe first, because sure enough, if you start mining it, you are gonna, you're probably gonna change its orbit in some way. And then it's hard to predict how it's gonna spin and where it's gonna end up in the future.

• 42:35Neil deGrasse Tyson?

  Good question. All right, keep them coming.

• 42:38Speaker 01

  Fascinating stuff here. I wish I cared.

• 42:41Neil deGrasse Tyson?

  When the asteroid's headed your way, you'll care.

• 42:46Speaker 01

  That's true, that's true.

• 42:47Neil deGrasse Tyson?

  We become the most important people in the world the day that happens.

• 42:50Speaker 01

  I've seen the Bruce Willis movies.

• 42:52Natalie Starkey?

  Exactly, it's all in the movies.

• 42:54Speaker 01

  I know, but I'm genuinely jealous because you guys care so much that you, it makes you learn. I'm gonna die alone and an idiot because I don't care about anything. I'm dead inside. All right. Doug Bartlett on Facebook, I know we have found organic material in tardigrades on asteroids. My question is, are these tardigrades thriving, quote unquote, on these asteroids or in a state of hibernation? If alive, could it be possible that two asteroids collide or contact and crossbreed organisms?

• 43:27Natalie Starkey?

  Okay, so I'm not entirely convinced we have found tardigrades on asteroids. Neil, do you? I'm not sure that's true, because that's a living organism and we haven't found anything living. So these tardigrades are like these crazy organisms that can basically survive anything. They're insane. They can survive extreme pressures and temperatures and they can also just go into hibernation for, I think, like millions of years and they can just basically survive anything and they come back to life again. Literally, this is the very edge of my knowledge about these things. This is very much astrobiology, which is not what I do, but they haven't been found on asteroids. But I think the theory they're talking about is panspermia, where we're basically looking

• 44:07Natalie Starkey?

  at transporting biological material around the solar system from one object to another. And that's one of the theories of how life got to Earth, in fact. It's not that well accepted in... I don't know. I don't know if it's fair to say that, but I mean, I I don't believe it personally. I don't think that's how life got to Earth. And but, you know, there is a chance that the basic building blocks for life, the the more basic carbon molecules came, you know, from comets and asteroids and were delivered to Earth in that way, but the actual organisms themselves weren't, as far as I'm concerned, anyway.

• 44:40Neil deGrasse Tyson?

  Well, but you just said that the tardigrade can survive anything. So it could survive a trip through space as a stowaway

• 44:47Natalie Starkey?

  Yeah.

• 44:48Neil deGrasse Tyson?

  in the nooks and crannies on a rock that got catapulted from one planet to another. So you said that earlier in this program.

• 44:57Speaker 01

  Wow.

• 44:57Natalie Starkey?

  I I did. I did just say that.

• 45:00Neil deGrasse Tyson?

  And now you're saying that you're not buying it.

• 45:02Speaker 01

  Oh, he's calling you out.

• 45:04Neil deGrasse Tyson?

  Calling you out.

• 45:05Natalie Starkey?

  So I think the issue is we need, you know, we'd like some scientific proof. So we need to do those experiments. We need to take those bugs into space. And I'm, you know, I'm sure actually on the outside of the International Space Station, they've taken organisms and they're basically seeing how they react to that radiation environment. Because it's not only temperature and pressures. Obviously, we don't like radiation. Our biological cells can't deal with it. We get cancer and we die very quickly. In fact, you know, all the astronauts that go into space, there are a much higher risk of radiation poisoning than you would be on the planet. So this is one of the problems that biological material has in space. So we need to do those experiments. We need to take those bugs out into deep space and see if they survive and then see if we can grow things out there as well. And so until we do that, I'm I'm not sure that things can survive in deep space with

• 45:49Natalie Starkey?

  no sunlight and for kind of billions of years that we that we'd require. But, you know, I'm I may be totally wrong.

• 45:58Neil deGrasse Tyson?

  That's a good way to end every statement you make. I could be totally wrong.

• 46:02Speaker 01

  I prefer the term, uh, special needs grades.

• 46:05Neil deGrasse Tyson?

  And tardy grades.

• 46:06Speaker 01

  Yeah, you go. But, uh.

• 46:09Neil deGrasse Tyson?

  I see what you did there.

• 46:10Speaker 01

  Well done, both of you. This is quite a a speed date.

• 46:15Neil deGrasse Tyson?

  So Natalie, we're running out of time. Do you have any sort of reflections, simple reflections you'd like the viewer listener to take with them as a lesson for this program?

• 46:27Natalie Starkey?

  Yeah, I think, I think, you know, someone like me, you're probably like wondering why I'm so interested in these objects. And I think it's just because I'm inherently interested in where we came from. You know, we're not on this planet for very long. Most of us 100 years if we're lucky. And in that time, I think, well, let's give a purpose to our life. I'd love to figure out why we're here, how we got here, and what we're leading to our future descendants. And if, basically, we may have only got here because of comets and asteroids, and actually in the future, we may die off because of comets and asteroids. They could collide with us and, you know, devastate all of humanity. So I want to understand these objects for many reasons, because of how we got here, but also to protect us in the future. And we need to understand what these things are made of,

• 47:11Natalie Starkey?

  and what their orbits are, and understand in so much detail so that we can actually protect the planet. I think it's important. I think everyone should be concerned about it, but not worried. I don't think we need to be worried that tomorrow we're all gonna die in an asteroid impact, although it could happen. But I think it's something we need to be concerned with for the future. So we're not leaving a ruined planet to, maybe it will be ruined in other ways, but we're not gonna leave it ruined with an asteroid impact in the future. And we can hopefully do something about it and divert the asteroid before it hits.

• 47:38Neil deGrasse Tyson?

  I'd like to think, just picking up on your point Natalie, it is, it's an intriguing and underappreciated fact that asteroids and comets may have been the bringers of life, if not the ingredients of life, but perhaps even life itself. And yet, they can also serve as harbingers of doom for the very life that it brought. Well said. Beautiful. And that is a cosmic perspective. You've been listening to, possibly even watching, this episode of StarTalk, Cosmic Queries: Asteroids and Comets Edition. I want to thank Natalie Starkey, friend and colleague, who went back across the pond.

• 48:18Neil deGrasse Tyson?

  Good luck in your new science teaching exploits at the Open University in the UK. And it's always great to have you. And how will people find more of you out there?

• 48:30Natalie Starkey?

  I am Starkey Stardust on Twitter and Instagram.

• 48:33Neil deGrasse Tyson?

  Starkey Stardust!

• 48:34Natalie Starkey?

  Which is my name, so.

• 48:36Neil deGrasse Tyson?

  Starkey Stardust. Great band from the 60s.

• 48:41Neil deGrasse Tyson?

  And you're also one of our StarTalk All-Stars.

• 48:45Natalie Starkey?

  I am, yeah. So I have other shows that you can go and listen to. I've had about four now. So I've got some on water in the solar system, a lot of asteroid stuff. I looked at the Mars Insight Mission, which is actually on Mars at the moment. So there's a few things you can go and check out.

• 48:59Neil deGrasse Tyson?

  Nice. Very good.

• 49:01Natalie Starkey?

  And we'll put a link to those shows in the description.

• 49:04Neil deGrasse Tyson?

  Excellent. Excellent. And Mark, you get around?

• 49:07Speaker 01

  I get around. I'm on the road every weekend doing my-

• 49:09Neil deGrasse Tyson?

  On the road again?

• 49:10Speaker 01

  My comedy stylings in a comedy club near you. And go to marknormancomed.com-

• 49:15Neil deGrasse Tyson?

  And I love your tweets.

• 49:16Speaker 01

  Oh, thank you, sir.

• 49:17Neil deGrasse Tyson?

  They're insightful and clever and funny.

• 49:19Speaker 01

  I love yours.

• 49:20Neil deGrasse Tyson?

  What more can we ask for what the world needs today?

• 49:24Speaker 01

  You're a big inspiration. Your traffic light tweet-

• 49:27Neil deGrasse Tyson?

  Oh, you remember that traffic light tweet?

• 49:28Speaker 01

  Of course. That's a joke. That's a bit.

• 49:30Neil deGrasse Tyson?

  Oh, my gosh!

• 49:32Speaker 01

  Yeah, I'm obsessed with jokes, and that's a great joke.

• 49:33Neil deGrasse Tyson?

  Oh, you know, I try joking, but it's, you know, they don't always land. But you know where I'm coming from. Thank you.

• 49:39Speaker 01

  I love it. I love it. Keep them coming.

• 49:41Neil deGrasse Tyson?

  All right, that's been StarTalk. I've been your host, Neil deGrasse Tyson, your personal astrophysicist. And as always, I bid you to keep looking up.