The Interstellar Comet Borisov C/2019 Q4 Featuring Leah Crane

0:00In what is very likely to become a completely new chapter in the history of astronomy, we now have the ability, increasingly so, to spot international visitors to our solar system as they pass through. The first of these objects in Muammua turned out to be far stranger than anyone had imagined, and now we have spotted another visitor. Now to see 2019 Q4 or Comet Borisov after its discoverer, we now have the opportunity to study one of these objects, now on its way out as Muammua was, but on its way in. Welcome to Event Horizon, with John Michael Godea. If you enjoy what you hear, fall into the Event Horizon, hit the like button and become

1:19an active subscriber by ringing the bell. Say a crane, welcome to the program. Hi, thanks for having me. Now Leo, we have a new interesting story, and this actually goes back a couple years now with Muammua, you know, the first interstellar object that we can say with reasonable certainty is not from this neighborhood. Now we have another, this new Comet Borisov. Can you give us kind of an overview of how this thing was discovered? Yeah, sure. So a Crimean astronomer named Borisov found it in his sort of homemade telescope on August 30th, and reported it to the planetary community at large, and more and more people started to follow it up. And as we got more and more data about its trajectory and how fast it was moving, it started to look more and more like it might be unusual, and not so much like the Comets that are from here that we're aware of. Now this one's different somehow though, because it seems to be in the photographs that

2:21I've seen of it that are coming, I guess, out of the Crimean Observatory. Is that it appears to have a coma, this appears to be a Comet. Whereas Muammua didn't look like that. Yeah, so Muammua, it's sort of a, it's like a sliding scale between an asteroid which is mostly rocks and a comet that's more icy. And this one does have a coma, which means that it's got a lot of ice that's outgassing into space, which Muammua probably was more on the asteroid side, although we think it likely had some ice on it. And so this does have that little sort of cloud around it of particles and a little bit of a tail. And one of the things that does is make it really hard to measure how big it is, so we're not quite sure yet what its size is. Now it also though, we have some time to watch this, because unlike Muammua or we caught it on its way out, this one we were seeing before it makes its closest past the sun, the Perahelian, right? Yeah, so this one will make its closest past to the sun, which will be probably just

3:23outside Mars's orbit at the beginning of December. The numbers aren't quite exact when, but sometime in the first and second week of December. And the fact that we've seen it so early makes it really, really exciting, because one of the reasons Muammua sort of remains quite mysterious is that we didn't have enough time to really study it super rigorously, because it sort of hurtled by and was gone and we spotted it when it was already passed through. Whereas with this comment, we can sort of watch it pass through the solar system, we have a lot of time, set up a lot of observations, and really learn a ton about it, and therefore maybe even about the system that it came from. But now this thing, because it has a coma around it, shouldn't that make telling the composition of the object easier? Yeah, I think so. People have already started taking images of the coma and looking at what color it is, and eventually we'll be able to take spectra and sort of extrapolate what that ice is made

4:26of. Right now it's looking very similar to comics that are from our solar system, but we don't have enough data to really know for sure yet. Now these sublimating ises, have you heard of anything yet about changes in the motion of the object, or have we just not done enough measurements? Because Muammua famously accelerated, and presumably that was because of sublimating ises. And this seems to have a lot more of that. So have you heard of anybody seeing anything that would suggest that this thing is changing in velocity? No, we don't really have a big enough arc of its trajectory to know that yet, and also right now, since it's on its way towards the sun, the timeline that would happen the most would be at perihelium when it closed. And I think that we should expect it to have a little bit of non-gravitational acceleration as that ice sublimates, just because we know it has more ice. We know it has ice, whereas in Muammua, before that acceleration happened, we thought it was pretty much rocky. Yeah, exactly. Muammua was sort of surprising.

5:26And there's sort of an undercurrent here that, you know, over the last 300 years since Edmund Holly that we've been looking at, comet orbits. We've never seen a hyperbolic comet, an interstellar comet, that was pristine. In other words, they never become great comets or anything like that as far as we know. Suggesting that maybe something in the interstellar medium degrades them, and they just sort of don't have so much ice. But then we have these two different objects, disparate objects, where one has a coma, the other one doesn't. So it seems that travel through the interstellar medium might be more complicated than we might have thought a few years ago. Do you get that sense that there's one of the really interesting things about these objects is how different they are from each other? Yeah, I think that is interesting. We don't really know how different they are yet, but, you know, there's a lot of different kinds of rocks in our solar system. And so we should expect a lot of different kind of rocks in other solar systems as well. And we do expect solar systems to constantly be ejecting materials.

6:31So I think we should expect some degree of diversity in these objects. Now this one is coming from, I think, the direction of Cassiopia, right? The constellation? Yeah. Is there any hope of trying to figure out where this thing might have originated from? So my impression is that in order to figure that out with any degree of confidence, it feels fairly unlikely that we'll be able to say this rock came from this star. But to figure out a more precise area, we'll need a lot more data. We'll have to watch its trajectory for a really long time, maybe up to a year, or, you know, ideally up until we can't watch it anymore. Because space is huge. And the trajectory of this object through the solar system is a really tiny segment of its path from its original stellar system to here. So we really need that segment to be as big as possible if we want to trace it backward over the course of, you know, maybe millions of years. Now, if you can, give us a sense of how well this object is being watched now in so far

7:33as you're aware. How many scientists and teams are taking a look at this object, as we speak? Um, watched a lot of them. I know that we have had images already or observations from maybe around 20 observatories. Lots of people are looking at it because it's fascinating and it's a whole new thing. We've never seen an interstellar comet before if you're not willing to call it a comet. There are some issues right now in the sky. It's fairly close to the sun. So we can't point any space telescopes at it yet until it moves a little bit further away because it would just burn out the telescopes. But there are a ton of ground-based observatories looking at it and it's being tracked, I think pretty much constantly so that we can make that arc as big as possible. Is this one like a moomo? Is this coming at it an angle or is it sort of on the ecliptic? What does the trajectory look like when you sort of step outside the solar system and look down? So it's coming sort of down through the solar system. It's a bit hard to describe.

8:36But it's coming in at sort of an angle kind of towards Mars from above the solar system and it will just pass right through kind of like shooting a bullet through a plate and it's moving incredibly, incredibly fast. So we'll have to really take care to be keeping track of it and take as many observations as we can before it sort of zips away at 41 kilometers a second. What about the future? All right, so what everybody would really like is a sample return mission. Is that in the cards for this object? I don't think it's in the cards for this object. It is theoretically possible, but it would take a lot of political will and a lot of money to make that happen. But there are teams at the European Space Agency in particular that are working on spacecraft that would be able to sort of intercept something like this and study it and take a sample. But for now, it's the sort of thing where we'd have to already have that spacecraft up

9:38and orbit ready to rumble when we spotted the interstellar object. And I don't think that's going to happen with this one. I think the saving grace though is that now that we've seen the second interstellar object and that there's no good reason why interstellar object should be passing through constantly, that someday we will be able to intercept one and actually check out the composition of such a thing, right? Yeah, I think it's fair to say that someday, maybe not in the immediate future, but maybe in our lifetimes, we could get a sample from one of these things. There have also been suggestions that, as you said, these should be passing through all the time. And in the lifetime of the solar system, some of them should have hit stuff. So we might want to go look around on the moon for interstellar objects. Those samples wouldn't be pristine because they would have fallen and crashed into the moon. But we might be able to find samples of these without actually having to catch up with one of them, especially since they're generally moving incredibly quickly. Well, there's some suspicion that Jupiter may occasionally capture such an object

10:42and that we might, I think there's two candidates actually for this, where they might have once been interstellar objects that Jupiter's captured and sort of incorporated into the solar system. So we could also maybe go look at those. Yeah, definitely. And there's lots of places we can look without necessarily having to catch up with these objects that are really hurtling through at a good clip. And basically, what we have to do is just study those because you don't necessarily want to send a mission to some tiny rock orbiting Jupiter. And they'd be like, well, it's just a rock, just like all the other rocks you'd see. It's not interstellar. You want to really know before you go. You should see, once you do have an interstellar object, though, it should be different because of isotopes. You should be able to say this is not local. Yeah. It should have ideally different isotope abundances than anything in our solar system because all of the rocks in our solar system were made out of the same cloud of gas. So they all have somewhat similar makeups.

11:42And you would expect that to be at least a little bit different in an interstellar object. But that is one of the big questions. Whether it would be all that different or not, whether other solar systems are all that different from our solar system. It'd be interesting if there were surprises. I mean, if you found, for example, low levels of phosphorus or almost an absence of it, then it would open up questions about, well, maybe there are parts of the galaxy that are not capable of supporting life because of abundances or are just wrong for it. So there is a lot of, you know, or you, you know, we find organics everywhere when we look and we could look at things like tholins and such that might be present on this an object like this and we might be able to get some sense that, you know, what is the organic chemistry of Milky Way? We would no longer have just a sample of one. Yeah. It's, I was speaking to Avi Loeb about a more and more a while ago. And he said, it's like having a dinner guest from a different country. You can learn a lot about it through their eyes without having to travel to that different country.

12:45And I really like that. It's, it's sort of like you're able to look into a different solar system in a very precise way through chemistry in a way that we wouldn't otherwise be able to do for a long, long time with telescopes or spacecraft. Yeah, it's, it's, it's an alluring idea. Even though we probably can't ever know where these, these, these things originated from, we can at least get by looking at multiple, you know, interstellar objects. You know, at least get a sense of what, what the Milky Way is like chemically. Is there something about our solar system that was weird? Do we see this sort of same chemistry everywhere or does it vary? And that's, that I think for me is what's, what's most interesting about these objects. Now it seems likely that, that we have an instrument coming online soon. That's going to reveal a lot of these things, the large synaptic survey telescope. What, what do you expect? Do you expect to be writing stories about this, you know, these interstellar objects every other week once that thing comes online? Well, you know, I think that eventually it'll get to a point where I won't be writing

13:49a story about it anymore because it won't be new anymore. It won't be new. Old hat. I think it'll turn on and we'll spot a bunch of them. And eventually my stories will go from, we saw a thing to, we deeply study the thing, which I think is great. And it, it all goes down to sort of the big question that so many researchers are trying to answer of our real loan and our real special. And I think this is a really interesting way to come at that question. I think it is. And I, I think, I think it, we couldn't be living in a more exciting time because not only are we spotting these objects, but we're, our instrumentation to spot them is getting infinitely better, very rapidly. What is your sense of this? You know, 20 years ago we wouldn't have even thought that we would ever see an interstellar object, yet here they are. You know, and there may be even, I mean, for all we know there could be interstellar meteorites sitting on the surface of the earth somewhere that, you know, someone hasn't yet found. So it just seems to me to be a completely new area of, of astronomy that seemed, at least

14:54to me anyway, years ago that, that'll never happen, you know, it's really amazing. Yeah, it's one of those things kind of, the thing I'd compare it to is exoplanets or gravitational waves. It's one of those things that we knew had to exist and we couldn't detect it. And I think, you know, where I researcher and not a journalist that would have been incredibly frustrating to know that there are these interstellar objects coming through our solar system because they must be, but we can't see them because they're moving so fast and they're so small. And suddenly, you know, we're about to enter this era with LST where we see handfuls of them and where you're not just finding them, you're studying them. And I think it's a really exciting time right now. Alright, Leah, that's about all we have for today. Thanks for appearing with us. Alright, yeah, no problem. Thanks for having me. Best of luck with your work. Thanks. Thanks. Have a good one. Comet Borosov presents us with a so far unique opportunity to study an interstellar

15:54comet as it passes through. Its closest approach to the sun will be in December of this year, but it's expected that scientists will be able to study it on its way out for some time after, perhaps as late as October of next year. What will they find? Will the object be similar to our own comets, or very different? And if similar, then why was Umu-Mu so different from everything else? For an in-depth overview of what we know about Comet Borosov so far, head over to my original channel, which I like to refer to as Old Trustee, where I have a new video going out now. Link below. Oh, Trustee, you mean the one with your attempt to say... Selfie. What? You drew that? It's fan art, and I encourage all your viewers to submit their own. There'll be a gallery video later. Won't that be nice? And on that note, next week I'll be joined by Fraser Kaye and publisher of Universe Today. See you then.