Asteroid Alerts, Cosmic Rocks & Life's Building Blocks: #493 - The Great Space Rock Roundup

Hi there, thanks for joining us. This is Space Nuts. My name is Andrew Dunkley, your host. Great to have your company once again. Coming up on this episode, Oh boy, it is jam packed with rocks. We're talking rocks of all shapes and sizes. And one of them that might not even be a rock. But our first story we'll focus on a rock that is heading our way and in twenty thirty two, according to the popular press, we're all doomed, but everyone else who looks at it scientifically is. Saying, well maybe not. Another new asteroid has been discovered and it can steer itself. We're also going to look at some rock samples. We're talking to Cyrus Rex Yep. Some new information from that little mission and a massive visitor in our deep dark past may have disturbed our planets. How so we'll tell you all about it on this episode of Space Nuts fifteen, Channel ten nine Ignition Space Nuts or three two Space Nurse as n I report it. Neil's good and Fred Watson is still away chasing beautiful skies. I've seen some of the photos Fred's taken off. The Aurora Borealis during his sojourn north and spectacular photos. They are so covering for Fred is Professor John T. Horner, Professor of Astrophysics at the University of Southern Queensland. Johnty, Hello, Hey, how are you going. I'm good, welcome again. It's good to have your company. Thank you. It's always good to be the subsidy Yukshman. Yes, yes, it's funny how that worked out, isn't it. Will we get straight into it because we've got a lot of rocks to sort out. I used to have a rock collection, but nothing like this. Our first story focuses on the Atlas survey and they've spotted a rock that might be a threat in years ahead. Now I need to make a confession. I spotted this story the other day when I was reading through some science information, and if I spot something that I think is worth talking about on Space Nuts, I'll send it to Fred. And in this case, I said it to you and said, look, I don't know if this is kosher or if it's the popular press going nuts, but it's on a very well respected platform, the Conversation, so I think it's got some credibility. Johnty emailed back and said, yes, I'd love to do this story. I was the author. I I didn't. I didn't read who the author was. But from now on I'm going to do that. Very embarrassing for me, Yes, but yeah, I gave it credibility because it was in the Conversation. If it was on one of the other platforms that shall remain nameless, I might have been dubious. But that being said, I think you know, in the time time to come, when this rock's getting closer, the popular press will do the doomsday stories for sure. So what, yes, what is the story behind this one? I will just flog up briefly. Actually, the Conversation is a very good reputable place because it's introduced. It's an Australian initiative initially that was introduced more than a decade ago to address the fact that a lot of specialist journalists were getting laid off and therefore there were growing problems with fidelity of information in the mentoring media, you know, stories getting misinterpreted and scientists as a result getting quite anxious about talking to media. And The Conversation was set up with an editorial team who were professional journalists whose job it is to get articles written for them and just help the authors write the articles. But the people who write the articles to discipline experts. So I won't say much about it because it's not what the podcasts about. But it's worth checking out for people because if you see an article in the Conversation, it's written by somebody who's an expert in that field, and therefore should be give you the true story, not necessarily the hyped story. So i'd be advocate out. I'll give you an example of a hyped story that I read this morning, and this has got nothing to do with astronomy, but a certain well known soccer player is in court and all the popular press are dumping on this person because of a supposed racial slur. She's actually facing charges of breaking a window. Yeah, there's a few things in that. So I come from the UKs. I've been following this as a football fan, and it's drunken, reprehensible behavior, but a lot of people get drunk things in the UK. Though, if you are recorded saying anything that is racially motivated, particularly saying it to police officers, that's kind of unwise. And that's what's led to all of this. Yes, so it's led to a lot of interesting coverage and a lot of very interesting discussion on football forums around the plast Yes, indeed, but I just thought it was a good example of them chiming in on, you know, the juicy bit, leaving out the fact that the arrest occurred as a consequence of malicious damage that was alleged yess, and then the additional charges a guess that they be layering the arrest. Yes, yes, again, very off topic. We've been here this thirty second. We've already gone on two tangents, so it's going to be a good EPI. So the Atlas survey and this rock that may or may not be hurtling towards Earth at some time in the not too distant future. This is a story of an asteroid that goes by the name twenty twenty four y R four. So these things always get essentially a barcode that tells you exactly when they were discovered. So the twenty twenty four means it was discovered in twenty twenty four. The first letter all was tells you which fortnight of the year it was discovered in so a it would be the first two weeks, be the second two weeks. In this case, why means it was the last two weeks so this was discovered on the twenty seventh of December. Interestingly, two days after it had a class encounter with the Earth. We saw it as it was going away from us. We'll tell you how hard these things are to spot. We've now got just over. A month's worth of observations of it, and it's kicked tough as a story in the last week or so because those observations have allowed us to work out the orbit of the object goes round the Sun just over every four years, which tells us that in eight years time it's going to come perilously close to the Earth, and within the level of uncertainty of the orbit, there is a chance of it hitting the Earth. And if you go on the CNOS Earth Impact Monitoring site for this object, you can actually check that probability out there by day, and every day it's changing. So when I wrote that article for the Conversation last week, it was one in seventy seven chance. Over the weekend it got as low as a one in fifty chance, and as of today, as we record, it's about a one in seventy one chance. And the reason that numbers going up and down so quickly is because we're getting more observations. So the headline for this in a lot of the media has been, you know, the global security protocols have been enacted. I can't remember the exact phrase, but everybody's at panic stations and it's not quite that bad. But what's happened is that astronomers around the world have been alerted to this. They've been told that this is a target of priority. So all the telescopes around the world that can look at it and making extra time in their schedules. To do so and get a lot of data. And what that data lets us do is refine our understanding of the orbit to better predict it fold in the future. And every twenty four hours they're running updated fit for the orbit. That gives you the parameters you see online, and that gives you this impact probability. And what the impact probability is really telling you is that on the data at which the impact could happen, which is the twenty second of December twenty thirty two, how big is the area in which this asteroid could be at the time it would hit us compared to the area of the Earth. So if you've got one in seventy chance it means the area of space the asteroid could be and is seventy times bigger than the cross sex of the Earth facing it roughly. Now, we know the time of impact very very accurately, because it's as this object moves across our orbit. But exactly where it'll be left right up down is the uncertain bit, and that's why there's this uncertainty. Now. We're not going to know unless we're very fortunate that this is definitely going to miss, definitely going to hit in the next few weeks. I think that's unlikely. It should be bright enough for us to follow with telescopes about April, and then it'll be lost, even with the biggest telescopes in the world, and that's part of why there's the urgency for these observations now. It'll then fly past the Earth again a distance of about eight million kilometers, so a hefty distance away in twenty twenty eight, and part of the reason to get all these observations now is to know exactly where it will be in twenty twenty eight so that we can do better follow up there with more prep and the key observations in twenty twenty eight will be rad our observations, so boundcerade our waves off it get the signal back, and that a gives you an incredible accurate position for the thing, which really helps you refine the orbit. But it will also allow us to figure out the size and the shape of the object with real accuracy. And with those observations in twenty twenty eight, I think by then we will know for definite whether it's going to hit or whether it's going to miss. But we'll also be able to predict where it's going to hit down to an accuracy of maybe ten or one hundred kilometers. So that's what those observations in twenty twenty eight will yield. And what we're doing at the minute is laying the groundwork essentially, So that's the background. Okay, So it's going to be another few years before we can get enough data to be more accurate. About twenty thirty two, I mean, how big is this? Think? Well, there is one possibility we might get data and be sure sooner than that, and that's if we find a pre discovery image, but nobody's managed that yet. So if this thing goes around every four years, it will have been passed us every four years in the past as well, so there's a chance it might have been picked up and not noticed before. And as soon as you get that information, that hugely improves the orbits, so that could rule it out or real it in very quickly. In terms of the size, we honestly don't know, but it's a caveator don't know. So what we measure with this object is the brightness of it in the sky, which is related to how much sunlight it's reflecting back to us. So if you imagine two objects that are identical sizes and one of them is more reflective, more shiny, then that one will look brighter to us it will reflect more like our way. Now, for this object, we know how bright it is, but we don't know how reflective it is, and so therefore we can estimate the size best on a guess at how reflective it is, but we don't know, and so we have a range of potential sizes. We think it's between forty and one hundred meters diameter, with the most likely sides being fifty five to sixty meters, but we won't know for sure until we get those red our observations in four years. Type all right, so what kind of damage would a rock that size do. There's two scenarios. Basically, we have scenario one, which is the most likely, is that this is a rocky, rubbly object like the thing that exploded over Cheliubinskin twenty thirteen or the thing that explooded over Siberia in nineteen oh eight, and the majority of near Earth asteroids are these kind of rubble piles because rocky objects are more common than metal objects. If it's one of these rubble piles, it will not have the strength to get through the atmosphere intact, and so it will fall apart and detonate, probably somewhere between ten twenty thirty kilometers above the ground. It'll probably get deeper into the atmosphere than the Chelliubinskin pacted because it's bigger. Essentially blow up nearer to the ground and that will create an air burst event. Now, the amount of energy dumped into the atmosphere will depend on the mass of the object, the size of the object. Essentially, it is roughly and because of how wide that size range is, this is a very rough estimate. It's comparable in size to the thing that happened that explooded over Tunguska in ninety nine. That is probably the biggest impact on Earth. It's certainly the biggest impact in recorded modern history, but probably the biggest impact on a time scale of a thousand years or so. That leveled an area of trees in Siberia of about twenty two hundred square kilometers, which is equivalent to the area of Greater Sydney. So it kind of drives that as being a city killer. So the kind of thing where if it hit over a city, everybody in that city would have a really bad day. Now, what the Tunguskar event showed us is that Earth is mainly empty space. We hang around as humans and we all gather together. So what that means is that an object like that hitting the Earth most of the time wouldn't cause any problems because it would hit over the ocean, or it would hit in the wilderness. But the flip side of that is, if the Tungusker event had happened two hours later, it would have happened over Saint Petersburg and millions would have died. Wow. So that's the kind of size of object we're talking about here. If on the flip side, it turned out that it's an iron object, the fragment of a core of an object in the astra belt that got big enough to differentiate out into separate layers, like the Earth has a core, a mantle, and a crust and then was smashed apart. There are objects out there like that. And the best example of the effect of something like that is found in the Arizona Desert. It's called meteor Creator or the Barringer Impact Crater, and I visited there a few years ago before COVID, and it's really spectacular. You're talking here about a hole in the ground about fourteen hundred meters across a couple of one hundred meters deep, a crater, and that crater was formed fifty thousand years ago by the impact of an iron meteorite about fifty meters in diameter, So the same kind of science scale as the object we're talking about. So if this thing is a solid metallic object, which acually stresses, the less likely option it would make it through the atmosphere intact because it's stronger. It'd hit the ground and carve out a big crater. If it hit the ocean, it would carve that crater into the water, causing them water to sols around and probably causing tsunami around the coasts. But it's still countered as been something that will build locally damaging rather than regionally or nationally damaging. So it's something to watch, something to be really interested in. But I'm not losing any sleep over the fact that if it hit us, it will be a huge Tatasha Effix, I think that is very unlikely unless we're very unfortunate. Yeah, okay, so too early to say, but we'll be able to get more data together in a few years, maybe sooner if somebody did get an image of it at some stage, but that isn't be determined yet. Okay, we'll revisit that story at some stage, I am sure. While we're talking asteroids, let's go on to this story which made me laugh. And this is an asteroid that was discovered in January of this year, but it turns out that it's not what they initially thought it was. Yes, and this is a recurring problem. I've mentioned before that our use of space is a bit like the wild West, that we've not had legislature and planning an organization keeping up with the explosion in our usage space. The story here is that an amateur astronomer I believe, detected a new asteroid in early January, and they were quickly scanning through all the old data. They found prediscovery images from twenty eighteen of this spec of light moving across the sky. So this thing got flagged on as an asteroid. It got given an asteroid categorization of twenty eighteen c x two I think it was. And it was quickly calculated that this thing was on an orbit that could bring it within one hundred and fifty thousand kilometers of Earth, so it's flaggers potentially hazard, that's asteroid. It was only a little bit later that people realized that actually the orbit of this thing matches perfectly with Elon Musk's sports car that decided to launch as a publicityst back in twenty eighteen. So Tesla Roadster that has been floating around on this elongated orbit that brings it near the Earth, and it got misidentified. So they put out a pressure release saying that the we now know what it was, we're retiring that categorization. It is not an asteroid. Don't panic. But it's not the first time this has happened. It's certainly not the last time it's happened. We keep getting human debris and detritus being picked up and identified as asteroids. People go back, they go through cataloged observations identify this in previous photos. You get an orbit and it distructs a large amount of time from people who are doing the work looking for things like Y four for objects that could pose a threat, and there's a number of issues around it. Now. Part of it is that there is no rules or regulations in place for people who launchings to space to keep track of them or to tell anybody else what they've launched and where the bits are. So it's seen these kind of stories in the past for satellites and space observatories. We've also seen it for spent rocket casings and things like that. Now that's a little bit of a problem when you're looking at managing the impact threat to Earth from asteroids, but it's also a problem in terms of other people wanting to send missions out there. And Jonathan McDowell, who's really one of the world experts in space flight, space travel and monitoring these things, has made a point that if you're flying on Earth and you're in an aircraft, you have to love a flight plan. You have to tell people where you're going when you're traveling as an aircraft safety thing, so that planes don't meet each other not expecting the other one to be there. Essentially, he says, and this is a direct quote from him in an article here, if you have to file a flight plan for a local flight on Earth, you should have to file a flight plan for an interplanetary flight, because you're going to get the same kind of thing. The airspace is going to become more and more crowded, and it's a safety issue and a management issue, but there are just currently no rules and no regulations around this out there. And the tracking problem is particularly important because you've got to remember that MASSA JP the astronomy community as a whole, I keeping track of all the objects we know over in the Solar System, and we currently know of nearly one point five million objects that they're tracking. So when you find a new object, it's not really straightforward to say, well, I remember, remember Elon launched a car. Maybe it could be that, let's check it out. Elon has not been tracking it and telling us where it is. So it is a real problem, and it's a big enough issue that people are flagging it up in the astronomy community, and it's another of these many facets of that balance between we wanting to encourage the commercial use of space, and we've seen such incredible innovation in there, the reduction of the cost of launching to space, all the rest of it. But at the same time you want it to be managed in a way that makes it sustainable and safe for everybody, rather than having companies essentially having free reign to do what they want. And so it's a challenging time. And this is just another of those issues that talk about transparency versus privacy, that talk about the right for companies to do what they want rather than regulations. Interesting, interesting one, you know. And at the end of the day, if you launch your spots cars into space, you should have to truck them. It was a very expensive exercise, but I think he can afford it, but I didn't. Didn't They lose it at one stage. So this is this is basically saying, well we found it again. Yeah, well, of course this is something of the size of a car that goes on an orbit beyond the orbit of Mars. Were the best one in the world, even the biggest telescopes on Earth cannot track the Tesla Rods in its entire robbit around the sun, but nor should There was that time having to do so when they could be looking for things that plus a threat. To its Mmmm, well I think he's got his money back in car sales. It was. It was a brilliant publicity stunt. He should have done it on April Fool's Day. That would have made it even more fun. But yes, okay, so now we know it's not an asteroid, so they've they've had to unname it basically all right. Yeah, there's there's a fun story. You can find that on space dot com. And the previous story about that twenty thirty two rock is on the Conversation website, written by none other than Professor john Ty Horner. This is Space Nuts Andrew Dunkley here with Professor Johnty Horner. Time to take a short break to tell you about our sponsor, nord VPN and they've got a great new year deal for you. Which I'll get too soon. 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Just go to gnordvpn dot com slash space nuts that's gnoredvpn dot com slash space nuts and click on get the deal and check out what's on offer through their monthly, yearly or two year plans. And the longer you sign up, the lower the overall price plus an extra four months free and of course their thirty day money back guarantee. And don't forget all their other amazing tools like cloud storage, threat protection, antimail where My favorite is the password manager makes life so much easier. All available depending on which plan you choose. It's inexpensive, simple to set up, and you can use it on ten devices through most operating systems, which is very impressive. Check it out. Today at NordVPN dot com slash space nuts. That's nord vpn dot com slash space nuts and click on get the deal. You won't be disappointed Space Nuts. Not quite. Professor Fred Watson, not quite. It is Professor John ty Horner. Fred still away and he should be back in a few weeks. We're still talking asteroids, Johnty And this one we've spoken about many times because this was a really exciting mission. The Osiris REX mission that got samples from Benu was Beno. Venue, wasn't it? And they they returned to us safely, which was all very exciting. But now they've had a chance to analyze this this stuff and it's been rather revealing. Yes, so one of the reasons that Benu was targeted is the suspicion that it's a fairly pristine object. It's one of these nearerth asteroids floating around. But based on observations of it going back a long time. The suspicion was that it's a kind of ashrog you call cabnecious chondract material, so it's old and in theory fairly pristine, and NASA sent the Asiris rex mission there touched down, gathered samples, gathered a huge amount of samples, more than twice as much as they were expecting to bring back, which amounted to them bringing more than one hundred grams of asteroid. Material back to the Earth. Now, this is the third time that somebody has visited an asteroid and brought samples back across. The Japanese have done it twice successfully before with the wonderful High Booster and High Boosa two missions. But this mission to ben who brought back a lot more material and is tacond a while for the results to kind of creep out from that debris that has been brought back. People have been analyzing it, working really hard. Should be said, they've actual quarantined off I think sixty grams of it to be held in storage for future researchers with better technology in the future, just the same incidentally as the Apollo samples that were brought back by the Apollo missions z Appollo astronauts. There are some of those that have still not been cracked open because they're preserved for future generations, which I think is brilliant. Yeah, that's great idea. So what they've been doing with the Benu samples is learning more about them, and we've suddenly had this raft of new results presented over the last few weeks, all discussing the findings from Benu, and they are really interesting in the context of the origin of life on Earth and how common life might be in the cosmos now, with Benu being really pristine and ancient, it's not been altered, it's not been weathered to any great extent, but it's an object that we know in the past was wet and warm because it's got clear type of materials on it. And what that tells us is that the asteroid we call Benu was once part of a much bigger asteroid that was a kind of environment where temperatures and pressures got hot in a full liquid water fret lea some time. That's why you've got these clayey type materials on it. In the analysis of the samples that have come back, they've found a lot of things that kind of reaffirm the idea that the building blocks for life on Earth could have been delivered by asteroids like Benu impacting the Earth late in the Earth formation. So the kind of real headline news story here is that they have found fourteen different amino acids in the debris they're brought back. And the reminder is that on Earth there are twenty amino acids in total that create all the proteins that we use. So they found fourteen of them, seventy percent of them in this one set of samples. You brought back one hundred and a bit grams of an asteroid and you found seventy percent of all the amino acids used in Earth. That's pretty amazing. Yeah. They also say that they've got I think it was all five nuclear bases that are used in DNA have been found in these samples as well as well as a very high level of ammonia and moonia is something that's often invoked in discussions of the origin of life. So this is in theory Italian is a couple of things. It's telling us that these things which are viewed as been part of that primordial soup that gave birth to life on Earth, could have been delivered from beyond, could have been delivered from asteroids. But it's also telling us that they're common in the cosmos, because for us to just go and visit an asteroid and bring back one hundred grands and find all these things tells you they're not rare. If they were rare, we wouldn't have found them yet. So I think that's really interesting and it shows the value of going there. The other thing, though, that is buried kind of deep down in the article here, that I thought was really interesting, is the other value of going there directly. So on Earth, there's this weird thing with life to do with chirality, so the handedness of molecules. So when you've got molecules that form a spiral, they can be left handed or right handed, which direction in the spiral goes. Essentially Now, on Earth, all life seems to use the left handed stuff. That's my understand the left handed chirality. And historically when people have looked at meteorites that have been found on the Earth and looked at the molecules in them, these long chain molecules, they found a preference for those meteorites to also contain left handed over right handed chirality. So there's always been some suggestion that that left handed preference comes from the material brought to us, But there's always been a bit of skepticism because the things that you find on Earth have been sitting on the Earth for a long time, so were naturally contaminated. So it's why, for example, if we find a meteorite on Earth that we don't know how long it's been here and find evidence that it has been altered by water, we can't say that it was altered by water before it got to the Earth because it's fairly wet. It's the same kind of idea, So that's been a hypothesis floating around for quite a long time. But in order to rule out the earthly contamination side of things, you've got to actually get samples that have not been contaminated on Earth. And that's what these samples from ben Who have given us, because we've gone there and collected them and brought them back and kept them very clean and very separate from the local environment. And what it turns out in the new results from Beniwe is that there is no preference for the left hundedness. You've got an equal amount of right hunded and left haunded material. So what that suggests is that the left hunded material is a result of the Earth rather than it being something the asteroids are bringing to us. If that makes sense. Ah, yes, I get it, I get it. It's pretty exciting because and I think I said this a week or two back, or maybe the last two episodes, that I believe the recipe for life exists everywhere and it's just a matter of getting the writer oven temperature and boom, it flourishes. I firmly believe, like we mentioned it earlier, there was a time where we just did not know that there were other planets beyond our own solar system, and now we've found thousands. It stands to reason that the same situation exists for life. Not intelligent life, but life. I mean, some would argue that if you watch the news, he'd wonder whether there's intelligent life on Earth and not for Earth, And yeah, I'm kind of with you. I've met a very small number of people who think that life is a uniquely Earth phenomenon, and they're quite often biologists, and the argument they've made is essentially that life is impossible. We're a fluke because no experiments have ever done have replicated life. It's too hard to generate. Therefore, we must be learning the universe. But if you make life even slightly easier to have happened than that, even a tiny little bit, there's just so much real estate out there that life must be out there in the universe, somewhere else. And that's before you bring into a discussion things like panspermia, which we talked about in recent weeks, which is essentially life having the ability to infect other places. Yeah, yeah, exactly, And I think that situation exists, and it's not just somewhere else out in the universe. There's there's potential for life within our solar system, on the ice us. Over the place. And here's another of those science revolutions we've lived through, which is when I was a kid, we were still in the domain of life is not going to be found anywhere else on Earth. You know, you don't talk about life elsewhere. That's a bit kind of quirking sci fi. So pendulum had swung very. Heavily that way. But we started to learn about objects in the outer Solar system. And one of the reasons that people have always argued that life would be scarce. Is that liquid water scarce? Of course, at the first past the Earth ceiling place with liquid water. We need liquid water for life, ergo life is very rare. But over the last couple of decades, what we've realized is that liquid water is actually everywhere in the cell system. Water itself is one of the most common things in the universe because it's what you get when you put the most common atoms hydrogen with the third most common atoms, oxygen. Hydrogen is seventy four percent of all atoms in the universe. Oxygen is one percent of all atoms. You put them together and you get water. So the great, great, great bulk of the solid material in the outer Solar system is solid water to ice. But what we found out the last couple of decades is that liquid water is everywhere. You know, we talked about Europa, which is the kind of standard bearer for this in the out of Solar system. But the more we've studied the icy moons of Juter and Saturn, the more evidence we get that many of those moons have subservice so otions. Some of the objects like the centaurs that I love, these small well couple of hundred kilometer scale icy bodies in the od Sol system. They're big enough they probably have liquid centers. At one point. There may even be a liquid water ocean buried beneath Pluto. It's just everywhere, and with that much real estate, it's very hard to imagine that where the only class that life has become established. Yes, as Bread is said to us many times, to the leap to more complex life forms is huge, but basic life forms very much a possibility. I firmly believe that, and I think common sense is starting to send people down that road. Anyway, that's a fascinating story about Benu. If you'd like to look it up, it's all over the internet, but space dot com again is a pretty good place to check it out. This is space Nuts Andrew Dunkley here with Professor Johnny Horner. Piece Nuts. Our final story, Johnty takes us to another object that passed through our Solar system. A long long time ago in a galaxy not so far. Away, and it may have disrupted some of our planets. Now, this got me to thinking, we've found a lot of Solar systems in our searches for exoplanets, and we've been mystified by the fact that a lot of them just don't look anything like ours, and we've wondered why, in fact ours seems to be different from most Could this be the reason? Possibly? Now, I think a tech home we've learned from the X planmet era so far as every planetary systems unique, and it's a bit like every person he meets unique because they've got their own unique lived experience, and every planetary system forms from a unique set of circumstances and experiences unique events through their evolution, so everyone will look naturally different. What we've tried to do in solsism mastronomy for basically as long as people have been doing solesism astronomy is understand where we come from. So how did the solar system get to look like it currently does, How did it form? How did it evolve? Now? The events that led to this happen four billion years and more ago, So we're trying to solve a very distant crime by looking at the clues that are there today. So it's a bit like when you're driving along the highway and you see a little bit of glass on the road and a little bit of a ding in the barrier, you can infer that somebody's had a bit of an ups moment, but you don't know what kind of carri it was. You don't know what the story was, so you've got to try and piece it together. And I'm sure the accident people will look at the skid marks and all the rest of it. Now, in the Solar system, we have a huge, huge, huge number of objects were mentioned earlier on more than almost one and a half million objects in the Solar system that we know, and we see where those objects are and where they are, We see what their orbits are like, we see what they're made of, and we have all of those things as evidence of the processes that have led to now. And there are puzzles. We don't have any models of solar system formation that perfectly replicate what we see because of this chaos, of chaoticity, the lots of random events that can contribute. Now. People have suggested for a long time that there could have been a close encounter between the Sun and a passing star or passing brown dwarf that sculptured our solar system, and a lot of that discussion has come from the Edgeworth Koiper Belt, this belt of objects beyond the orbit of Neptune. That's like an icy analog to the asteroid belt, and the outer edge to that is quite sharp and distinct. So could that have been sculptured by a passing star scouring the outer edge of the Solar disc away? For example, we have discussions of planet nine based on some of those distant objects that are moving on orbits that are hard to otherwise explain. So this is that kind of game that astronomers are playing all the time, which is how do we explain the oddities? How do we get to one understanding of how we got to where we are now based on our best models of the generalities of how planet systems form. And that's where this work comes in. So we know a lot about the orbits of the planets, and one of the things we know is that, to first order, if you draw the Solar System on a bit of paper, you're not far wrong. The orbits of the planet's all moving pretty much the same plane, but they're not perfectly aligned. They're tilted to one another by a few degrees. Mercury is silted by about seven degrees, for example, with the biggest tilt. The orbits are not perfectly circular. They're all spread out in a specific way. Now, there's been a lot of studies in the past looking at the migration of the planets, how they've moved over time from forming in one place still living in another. And Renu Malhotra, who's one of the greats of solar system dynamics, was one of the first people to discuss this back in the early nae nineties when she did work looking at the orbit of Pluto and inferring from that that Nettune must have formed closer to the Sun than it currently is and then in migrated outwards, pushing Pluto with it, And that is now just established scientific canon. That is an explanation that works. It fits with all the other objects we've found out there, and it was incredibly insightful and brilliant work thirty three years ago when she first identified this and modeled it and showed it to be the case. Now, the reason I mentioned Renu Malhotra is that her latest work is what is the interesting story today. She's looked at the oddities of the orbits of the planets, both the treasural planets and the giant planets, and asked the question what could have caused this to answer that she looked at the idea with her team that the Solar System is moving through a galaxy. Weather are lots of other stars and lots of smaller objects, lots of brown dwarfs, lots of planets, and particularly in the environment whether Sun formed, there were lots of other things forming, So you have a higher chance of class encounters. As she said, what if there had been a class encounter, Let's run a huge number of simulations. I think she ran more than fifty thousand individual simulations, all running for more than twenty million years, where in each simulation she had the Solar System and an interloper, an object flying through, not bound, not gravitationally held by the Sun, but just passing through. Where you change the mass of that You go from something the mass of the Sun all the way down to something the mass of Jupiter, and you change the trajectory the speed it's coming through, and how close it gets, and how tilted that trajectory it's And the question is can any of these scenarios provide a result that looks like the Solar system we see today? In other words, could this be an explanation for what we see? And the result is, yes, a large number of the scenarios led to systems that looked very similar to our own, particularly with less massive objects penetrating really deep into the Solar System. So not a one solar masses are passing at one hundred Au, but objects comparably mass to and a bit bigger than Jupiter passing through the domain of the planets, and this can do a really good job of fitting what we see of the current orbits of the planets. The best scenario they found, the one that was the closest fit to what we observe today in their simulations, was a planet the mass of eight jupiters, So that's a massive planet, but not yet a brown dwarf. It's still a big planet passing through the Solar System with the closest approach to the Sun of one point six y nine Au, so that's just outside the current orbit of Mars. And that individual simulation was the one that resulted in a planetary system that looked the most like our Solar System. Now it's not saying that's what happened, but rather it's demonstrating that this idea, of this hypothesis can work to explain everything we see today. Now, the next step for work like this is to make predictions. So, if this kind of model was the case, if this is what really happened, what will we observe in the coming years that corroborate that, What would it predict? And it's a wonderful time to do work like this because we've got the Verra Ruben Observatory coming online in the next year or two, which is the most ridiculous astronomical telescope ever built. It's got a main mirror about eight and a half meters across, but it's like a super super fast camera lens, except eight and a half meters across, so in image and area of the sky eighty one times bigger than the full moon every ten or fifteen seconds, letting it serve the entirety of the night sky once per week forever and ever more wow, detecting objects up to a billion times fainter than we see with a naked eye. So the predictions are that Verra Rubin in the first year of observation will detect a number of objects that will increase the amount of stuff we know in the sol system bathacter of ten to one hundred times, so from one and a half million object, it will go to fifteen or one hundred and fifty million objects, and that will be a huge raft of new information, new clues for the detectives to use to try and solve that crime, to try and fit to the different models of planet formation. So it's a perfect time to do work like this because you can say this is what we should see with vera Rubin, and if this model is actually true, we'll find a lot more evidence for it in the coming year. So it's really exciting work and a really exciting time to be doing it. Yes, indeed. Yeah, and just quickly, this object, what could it have been just another guest gard or a brand dwarf? Describe it as a rogue planet. So if it's eight times a mass of Jupiter, it counts as a planet rather than the brown dwarf. Now, this is I suspect eventually going to become a little bit of a bone of contention because of it being how we classify things. So the boundary between planet and brown dwarf is currently set purely based on the mass of the object, not actually on how they formed. But the idea here is that if you form with more than about thirty times a mass of Jupiter. The temperature and pressure in your core will get high enough few to temporarily undergo uterium burning fusion to turn the deuterium into helium, and that'll be short lived because there's not much deuterium there. But that means you're something that isn't a planet in actuality. Where that line sits depends a little bit on what you're made of and how you formed, But at the minute it's good enough. But I still think you've got an interesting thing. Of the standard model of planet formation is you form through this thing called core recretion. You gather a load of rocky material and metallic and icy material first, and eventually get massive enough to hoover up gas. You've then got a model that is instability, where gasous smushes together and form something, and that will often form brown dwarfs and stars. If you find something that's eight times Jupiter's mass but it formed without a core, would it not be fairer to call that a brown dwarf? If you find something twenty times Jupiter's mass but it formed like Jupiter did, is it not fair to call that a plant? And so there's going to be a friction at some point between a size based classification scheme or a mass based classification scheme and one that's based on the phenomenology, the kind of formation, mechanism, the structure of the object. And I'm sure that'll be discussion that will be had in a few years when we start finding more objects in this overlapp reachion. Essentially, yes, and we should point out that this paper has yet to be peer reviewed, but it has been put in the is it the a z ev is that, hey, you pronounce it archive a r XIV. Now this is well worth everybody knowing about, actually, because most astronomers and most researchers in all related fields of astronomy, when we get a paper accepted or when we submit it on which of those thresholds It depends on your sub discipline and astronomy, quite often we'll put a paper up in an unformatted, not in the journal format version on the archives, so that it's freely available for anybody to download and comment on. And this is a resource that's been there for decades, to be honest. So what it means is that even if you have a paper that's published is behind a pair wall and you can't get to it. The likelihood is you'll be able to find a copy of it on the archive for free. And my suspicion is that this paper has been put up there. It's Garrett Brown, Rennu Malhottra and Hannah Ryan, all of whom are very well regarded, very reputable scientists. I suspect they've put it up there whilst it is under pay ofview to just get a bit more feedback. So are people doing that now get more of their colleague to reach out and say, oh, this is brilliant. Have you considered x y Z? And it usually leads to a stronger paper in the end. Okay, So if you do want to check it out, it's on the archive dot Orgwards website, which is spelled a r x iv dot org just to confuse us even more, orspace dot com. That's always a good source of information. And that wraps up another program, John, do you thank you so much. It's an absolute pleasure. Thank you for having me. Oh, it's always good, always good, And don't forget to visit our website between episodes. You can do that at space nuts podcast dot com or spacenuts dot io and you can listen to back episodes of the show. You can visit the Astronomy Daily news feed and sign up for that so you can just keep getting astronomy information on your in your inbox, there's a supporter button if you're interested in doing that. We would never force you to do anything like that, but if you're interested, please check that out. And thank you to all those people who have voluntarily subscribed to Space Nuts. We certainly do appreciate your support. That's just about it. Oh Hugh in the studio couldn't be with us today because apparently what he did was he put on a space suit and was last seen heading out of the Solar System in a Tesla Roadster. And from me Andrew Dunkley, thanks for your company. We'll see you on the very next episode of Space Nuts. Ohias, you'll be This to the. Space Nuts podcast available at Apple Podcasts, Spotify, iHeartRadio, or your favorite podcast player. You can also stream on demand at bites dot com. This has been another quality podcast production from nights dot com.