#469: Ryugu's Magnetic Mysteries, Arecibo's Silent Collapse & Venusian Impact Revelations

Hello again, thank you for joining us. This is Space Nuts where we talk about all sorts of astronomical and space science things. And coming up on today's show, we're going to get some more information from Reugu, the asteroid that they took some samples from about four four years ago. It's back in the news because, yeah, we talked about it a few weeks ago, and now we're looking at maybe the origins of our outer Solar system. Some new information on what really happened to the Aricibo Observatory and it's a bit of a sad tale. And then we head the Venus. Now, Venus doesn't have many big asteroid impact or impact craters, and they're not very old compared to the rest of the Solar System. However, they think they've found one that breaks the mold, certainly broke Venus. We'll talk all about that on this episode of Space Nuts fifteen Guidance Channel. Ignition Space Nuts or three two. One Space Nurse as when actually bought it. Bill's good and here he is the man of the hour. It is Professor Fred watsonn Astronomer at Large. Hello, Fred, Hi Andrew, how are you doing. I'm not I've noticed that in most of the recordings we do, I wear dark colors, so today I thought i'd wear a white shirt. It's actually one of my golf shirts, because I believe it or not. Before we recorded today, I went out and had nine holes and I was running so late because it was slow, I had to come straight in here to record. So I don't smell too good, and that has caused Judy to leave the building. So really, Wellucky, this isn't smell a vision. Yes it is, but it sort of harks back to what we're talking about a couple of weeks ago about maybe aliens will communicate by smell, so you might be sending out a signals to the alien world. Well, they'll never come here, that's the case. I won't want to come. It looks very smart, Andrew. And actually you've caught me off guard because I very nearly wore a light colored shirt today, and then I thought, I know Andrew will be dressed in something dark. I've just got the same little blue one. A well, look at that. You know. Unfortunately, golf shirts that are white tend to show a lot of dirt. And yeah, that's why I've got the collar up because all the dirts. It's horrible like that's here. Plus our golf course is a very dirty, dusty golf course compared to most as well known ones you see on television. So yeah, before we get onto the stories, fred I read something that I thought would interest you, given that we talk about this semi regularly. But the week just gone, Russia aid a record launch of satellites. They put fifty three satellites into orbit in one launch the other day, which is a record for Russia. But what interested me about it was the payload. Wasn't just Russian satellites. I mean, they've got satellites for their own purposes. I think most of them were, including their news agency tasks I think it's called. So there were Russian satellites, there were Chinese satellites on there, which probably shouldn't come as any surprise. This one might surprise people though. Iran a couple of satellites for Iran, and they launched a couple of SATs for Zimbabwe as well. Yeah, but that just adds more satellites to the growing numbers in orbit around the planet. The Russians still have because they were contracted to one WEB, which is one of the satellite consolation companies actually owned I think the principal shareholders a British but other countries as well, and one Web originally contracted to the Russian Federation for launches with their soyots launch vehicles. And when the invasion twenty twenty two invasion of Crimea took sorry of Ukraine took place, the I can't remember which way around it was, but essentially yes, because of the various boycotts and things of that sort, the Russians commandeered those twenty twenty one web spacecraft that they had already to go. They were going to launch twenty one Web satellites, but they've still got them, and one Web very quickly changed and went with SpaceX. In fact, yeah, gosh, yeah, I wouldn't like to be a lawyer riding up contracts for all this kind of work. Exactly. It sounds like it's a pretty amazing business the luks in it, yes, exactly. Yeah, But that satellite, of all those multiple satellite arrays that are starting to build up around the planet just get thicker and thicker, which, as we previously mentioned week or two or three back, not a good thing for the environment either. Not just people who want to look out into space. Speaking of looking out into space, well, this was actually a mission, the Higher Buss two mission to Reugu about four years ago, when it retrieved some samples from the asteroid and brought them back and they've been studying those and a few weeks ago we did talk about one of the things that Reugu has now revealed in terms of planetary formation and maybe how life evolved on this planet. Now it's revealing more data on the origin of our outer Solar System, and it sounds like it was all done with magnets or was a blue tack magnets. Yeah, it is an interesting worry. This is quite complex, but you're absolutely right. It's more data coming back from the samples of the asteroid Yugu, but brought back, as you said, by Hyabusa two in twenty twenty. And so what has happened. As well as the chemical analysis that you've just referred to that was done on the various grains of material from this mission, scientists have now done magnetic analyzes and basically these have been done with some tiny grains of dust from Riugua, only about a millimeter across, but they've been measured very accurately by device called a magnetometer, which, as you might guess, measures magnetic field strength. And so they've essentially stuck this thing in a laboratory with a magnetometer, and the tiny grains have had their magnetic fields sampled. And the interesting bit is there's no sign of a preserved magnetic field in these samples, which is a surprise. I'll tell you why in a minute. I'm looking at Fitz dot Oak, one of our favorite websites for this news, and I'm going to read a little paragraph from their article on this which explains it a lot more accurately than I could. The scientists determined that the samples held no clear sign of a preserved magnetic field. This suggests that either there was no nebula field present, and by that they mean the field of the magnetic field of the nebula from which the Solar system formed, and that was a cloud of gas and dust. It suggests that either there was no nebula field present in the outer Solar system where the asteroid first formed, or the field was so weak that it was not recorded in the asteroid's grain. If the latter is the case, the team estimates that such a weak field would have been no more than fifteen microtesla in intensity. Now I think, as I understand it, I really should check this, but I think that's about a quarter of the Earth's magnetic field. So there's a bit more to say though, So that the Riugu samples didn't really have any magnetic field, and that's a surprise because we believe that nebula probably would have had a magnetic field. So another paragraph, if I may. The researchers also re examined data from previously studied meteorites. They specifically looked at ungrouped car carbonaceous chondrites, which are meteors meteorites that have properties that are characteristic of having formed in the outer Solar System. Scientists had estimated the samples were not old enough to have formed before the Solar nebula disappeared. Now, the solar nebula is the cocoon in which the Solar System was born, and it was eventually blown away by winds from the Sun when it went through a windy phase. So it says any magnetic field recorded a record that the samples contained then would not reflect the nebula field. But the team decided to take a close So look, we reanalyzed the ages of these samples and found they are closer to the start of the Solar System than previously thought. We think these samples formed in this distant outer region, and one of those samples actually does have a positive field detection of about five microtesla, which is consistent with that upper limit of fifteen microtesla they they spoke about before. So what they're suggesting is that the outer Solar system, way beyond the orbit of Jupiter, probably beyond the orbit of Neptune, had a very weak magnetic field, but were still strong enough that material from the very limits of the soule and nebula were pulled in and perhaps formed things like Uranus Neptune, some of the you know, the smaller bodies, the trans Neptunian objects. And a comment from one of the authors of this paper and really credited who they are, but they are a group of scientists in a number of different universities, led actually by a postdoctoral researcher at Cambridge University in the UK. So they go on to say, when you when you're further from the Sun, a weak magnetic field goes a long way. It was predicted that it doesn't need to be that strong out there, and that's what we're seeing. But still it's a real thing that the magnetic field is real, but it was predicted to be weak, and that's what they're seeing with the evidence that they're getting from these Yugur samples and some earlier meteorites that have been delivered to us from space, probably by an asteroid in a few million years ago. So fifteen micro tesla, which is only thirty percent of our own magnetic field, he is today, which is which is fifteen micro tesla. So so that's not that's not a big number from what you say. Yes, that's right, it's it's not a big number. I mean, I've always thought the US magnetic field was quite healthy, but it's you know, it's when you compare it with some of the magnetism that's used in industry or in scientific research, it's pretty weak. Yeah, well, there's a bootknote. You have to recharge a tesla halfway to Sydney. Especially if it's a micro tesla. So one footnote to this story is that the same team they're going to look at samples from the asteroid Benu, which was which is also had samples returned to Earth, this time by NASA's cyrus Rex, not a Cyrus rocks, but the cyrus Rex space grab came back to Earth in September last year. So it would be really interesting to see what results they get from that if they do get their hold on get a hold on some of these samples from Benue. Indeed, you did. Say something that I picked up on and I thought it was worth revisiting. You said, the nebula that created our solar system was ultimately blown away by the Sun or the Sun's solar winds, whatever. So even at the very beginning, we were destroying our creator by the said, yes, that's right, blowing it away. That's right. So we know that stars forming gas clouds, clouds of gas and dust. We see it. You know, when you look at the pillars of creation, that's what you're actually seeing, pillars of dust with stole formation taking place at the middle. And we know that very early on in the life history of a star it goes through a phase which is known as the t Tory phase. T Toy is the name of a variable star and it's the sort of you know, basically the prototype of this type of activity. And when they're going through the t tourist phase. They're sort of blowing away the rest of the debris. And we see that too the Pliodes, the PLI d Es star cluster, which we see as the seventh Sisters in the sky in our summer sky here in Australia. They are when you look at them with a big telescope or even with a small telescope these days, with the modern detectors that we have, you can see they're surrounded by a sort of blue shell. There's a lot of blue material in them, and that blue is the reflection of light from dust. It's actually why smoke. It's the same thing that makes smoke look blue when sunlight falls, and it's a process called rarely scattering, which scatters the blue light preferentially. And so we see all this blue dusty stuff which is surrounding the Pliodies. Now we think the Pliodes are only about ten million years old. They're a young star cluster. So those stars have just gone through their te tory phase. And what we see is, you know, the last remnants of that dust cloud, the cloud of gas and dust in which they were born. So it's blown all the debry away and the Sun must have done the same thing as well, probably not long after its formation four point six billion years ago. Yeah, it's just gone, hey, I'm here now, get wreck off. So just sweeping up, sweeping up the debris really yeah, yeah, cleaning up after itself. Maybe, yes. And yeah, it's exciting that we're getting so much data from such a small sample from her Reugu asteroid. And there'll be more to come, I do not doubt. If you'd like to read up on that story fizz dot org, as Fred said, or you can read the whole thing lock stock and barrel with the five million people who signed the report in the journal A gu Advances. There's a space nuts Andrew Dunkley here with Professor Fred. What's an Okay, we've tacked all space nuts now to a story that we have done a couple of times, and that was the demise of the Aricibo in Racibo Observatory in Puerto Rico. I know it's one of those, yeah, I knew it was one of the ricos Puerto Rico. This was a really sad one because this is a famous one for all sorts of reasons. It's the one that sort of nestled into a mountaintop, and they've used it in movies. It was used in the Jodie Foster film Contact, and it's just it's a very used to be a very favorite place of cinematographers but also astronomers, and it achieved a lot in its time, the Aracibo Observatory, but then a few years ago it collapsed rather dramatically, and they have been looking into the reasons why, and now it appears they have discovered the cause and effect. And it's a bit of a sad miss by the sound of it. It is. That's right, you're quite right, Andrew. It's got a very very distinguished history of this instrument. Built in nineteen sixty three, it was originally for what's called imospheric research, kind of looking up at the atmosphere and measuring the radio radiation from it. But it was taken over in nineteen sixty seven by the National Science Foundation for the astronomy community and did all kinds of really interesting things and actually shared the cost of maintenance and upgrades and things of that sort. Lots of discoveries, don't really have time to talk about them now, but one of them was a Nobel Prize winning discovery. The binary pulse are discovered in nineteen seventy four. So the you know, the issue, I guess took most of us in the astronomical community by surprise when the demolition happened, But it sort of was an accident, not quite an accident waiting to happen, But there had been weakening of the structure over a period before that. It was twenty twenty when the thing finally collapsed, but apparently the failure of the structure actually began three years before that. In twenty seventeen, there was a hurrican Hurricane Maria, which went through Puerto Eco on September the twentieth, twenty seventeen, and you know, that bombarded the area with winds that were in the region of one hundred and sixty one hundred and seventy maybe a bit more kilometers per hour rather more than one hundred kilometers, rather more than one hundred miles per hour, and that was you know, that was something that hammered, the hammered the structure. But the review that was carried out after that, there were inspections that were done in detail, and the conclusion of those inspections was that no significant damage had jeopardized the Racibo's telescopes structural integrity, some of the issues were suggested to need repairs, but there were other things that caused those repairs to be delayed. And even so so they thought that this was you know, this was not going to be an issue. And actually the components that were going to be repaired weren't the ones that failed when the collapse actually happened. Yeah, that's a pretty significant point. Even though they didn't fix certain things. Even if they had. It would still have they weren't. They weren't the problem. Yeah, yes, that's right. And then in August and November twenty twenty, there were two cables that failed, and that basically was the thing that said, look, we've got a problem here. We think that the telescope is not recoverable from these cable failures, and they were going to decommission the telescope and then have what they called a country demolition to avoid the catastrophe. So that was all sort of in train towards the end of well in November twenty twenty. That was August and November when those two cables failed. But then on the first of December there was a failure of more of these cables, and that's when the catstrophe happened. The instrument platform collapsed into the dish, took off the tops of the support towers, and damaged some of the observatori's other buildings. It was really a catastrophic end that probably people had in the back of their mind already but when they were working towards trying to avoid it. And it seems that some of the fractures were called caused by zinc decay in the sockets that held these cables what are called the spelter sockets. Zinc decay in those sockets that really led to the fracturing that wasn't that wasn't identified as an issue after the hurricane inspection, So there would as you've just said, they would never have picked out what was going to eventually cause the collapse. So yeah, from what I read the the capacity to actually identify the problem was nearly impossible. It was an invisible issue. Yes, I think that's correct. So you can't that's that's right. You can't really blame the engineers they there were the failures were in uh, you know, parts of the structure that weren't available for inspection, like the innods of it and things that really you would you would expect to last forever, but they didn't. Yeah, that's very sad and such a such an iconic piece of infrastructure, which I'm sure most people would recognize as soon as I saw a photo of Aciboy. It's so it was so popular just because of the way it was built and the way it was used, and it's some some of its great achievements, as you mentioned, Fred, but it was a bit of a slow death. I mean, it was really probably beyond salvage before they identified that there was a problem by the sound of it. I think that's correct. That's a comment analysis. Yeah, And of course, now we have the Chinese Fast telescope, the five hundred meter apertures Phyico telescope. That's the sort of dwarfs are a Siba actually Raceba was three hundred and five meters in down the two it was one thousand feet. The Fast is half a kilometer in diameter. That's a very very big dish. Indeed, it's a similar sort of structure. Though. Indeed, yes, and and if people are interested, they did actually film that final collapse. It was they just happened to have a drone flying over Arasibo at the time, and they got footage of the collapse, so you can actually see it on YouTube if you're if you're interested, it's it's pretty sad to watch, to be honest, I have seen it myself. It's yeah, such a such a wonderful piece of kit as Fred would say. But yeah, all gone. Now are they going? Who I suppose they're gonna have to clean it up? Or they've already probably done that or starting to do that. That's a work that's right, that's a work in progress. But we do believe from statements made by the National Science Foundation that it will be turned into an education center specifically to carry on, you know, as a research center for stem How can you best teach science, technology, engineering, and mathematics. How can you teach that to young students? This will be what it will be doing, so it will have an enduring legacy, as Universe Today describes it. Yeah, it's hardly surprising when you look at Hurricane Maria, because in our language, winds of up to two hundred kilometers an hour. You know, most large structures would struggle with that, and especially something that was built in the sixties when they didn't have the kind of technology to reinforce big structures like they do today. So yeah, very very sad. Indeed, that's a story also on fizz dot org. Fife Space Nuts. Fred to our final story today and we head to Venus, one of the more mysterious planets in our Solar System, simply because we can't see it beyond its atmosphere, but we can use radar to map its surface, which has been done very effectively. One of the things that's fascinating about Venus is that its craters are much smaller, much younger than most of the creators found elsewhere in the Solar System. But now they think they've found one that's probably the oldest and most definitely the biggest to be discovered at this point in time. But what's really weird about it is that it resembles impact craters on ice moons further out in the Solar System, which I guess got people scratching their heads and they've tried to figure out why, and it looks like they might have. Yeah, that's right. It is a fascinating story, and it's almost one of these accidental discoveries astrophysics is so full of, so it's radar data that you're always looking at when you're talking about the surface of Venus. I remember the Magellan spacecraft. I think it was I think I'm giving it the right name, was the one that gave us the best radar maps of the surface of Venus and the some of the features that came from those radar maps are similar to what we find on Earth. There's mountains, there's things that look as though they're definitely volcanic, you know, volcanic cones. But they're also what we call longitudinal structures, which are called tesserai. And these I suppose, you know, we use the word tessellated, meaning things that are rectangular in shape, and these tesserai are basically, if you imagine a radar map, they're more or less straight lines on the radar map, all going in the same direction, and they're caused by highly high levels of disruption geologically in the surface. And then they're thought to be at least one and a half billion years old, so they go for a long way. They cover hundreds to thousands of kilometers, and probably up to ten percent of the planet is actually covered with these things. However, there's a group of scientists who were looking at these testa in detail, and they noticed that some of them were going the other way and they were sort of at right angles to the main ones. And when they looked more closely, they found that actually they weren't straight lines at right angles to the testrie. They were forming a curved shape. They had a curvature to them, and they were concentric. They're described as beautiful, concentric structures that were very different from the rest of the test ARide. That's one of the researchers. And a lovely quote here. When nature gives you patterns like that which are so obvious, you know they have a story to tell. I like that very much. So that's say it suggesting when you've got something that's circular, and these stripes are circular, it's not a complete circle, but and their concentric. That's to say they have a distinctive center. What you're thinking about is an impact crater. And so this is a quote from one of the scientists working on this. Some of them are from Spanish University. The Yes if the structure. Actually I'm not quoting here. I think I'm quoting from the Sky of Telescope magazine, which is where this article is if the structure was an impact crater, then it will be more than five times the size of the next largest one known on Venus. The size that fits well with massive impact ours flying around the Young Solar System. But it's different, that's the thing. It's quite different from the normal impact structures that we see. It's got these concentric rings, and there's nothing like that on the Moon. There's nothing like that on Mercury, there's nothing like that on Mars. But as you said, they did find exactly similar structures on two very different worlds. One is Callisto, it's one of Jupiter's moons, and the other is Europa, one of the other moons of Jupiter. And these are ice worlds, exactly as you've said. There are worlds with an icy covering overlaying a global ocean, which itself overlays a rocky core. And that's really weird because Venus is not an ice world. It's quite the opposite. But what it suggests is that there may have been a time in Venus's past when it had a similar structure to the ice world. So, as I said, ice worlds are a layer of ice with water underneath. If you think of let me, guess, go for it. The floor is lava. Yeah, so if you imagine a lava crust, a thin lava crust overlaying molten lava, then you've got a similar structure, a solid layer on top of a liquid and so this is yeah, that's exactly the same effect. This is basically what led this team of researchers to model what would happen if you had an object hitting a solid crust covering lava lava, either a lava ocean or lava pools. And apparently what they found, and this is again caught in from SCYN telescope, the team founded a single large object hitting a hard six kilometer thin crust could melt the underlying layer, splashing chunks of solidified scum to make the tessra, but a single impact couldn't simultaneously make the ring structure. And so they now postulating basically an initial impact that produced that straight line crinkling that I mentioned the tesserai, but then another one. So what that leaves is a thin crust over a pool or an ocean of hot lava, and then the next one, a next impact while that pond is still fluid, another object hits shatters the crust again, and that's when you get the curved impact structure, the stuff that we see similarly on Europa and Galistem So really quite an extraordinary bit of research. But it may well be that they've pinpointed exactly what happened to the early Venus, because we know that in the early history of the Solar System it was you know, it was a palish place. There was debris charging around all over the place, bits of unbuilt planets and asteroids and all the rest of it. So impacts were very high, what we call the late heavy bombar. Indeed, and and I suppose now, Fred, if it's confirmed that this is a major impact crater, they'll have to give it a name. The one on Callisto has got a great name. It's called Valhalla Crater. Yes, well they would surely have to name this, wouldn't they. I think it will get a name. Yes, that's right. Once again, the names of everything have to be ratified by the International Astronomical Union. But I think the suggestion would come from the authors of this paper as to what it might be. I think the lead author is Vicky Hansen from the Planetary Science Institute so I'm probably thinking now about what this could be called. Yes, yes, it's quite a discovery and great technology given we can't see the surface with the naked eye. Yes, that pickup. Indeed you can read that story Fred mentioned at skuy and telloscope dot org. We're all done. Thank you for your company. Don't forget to visit our website and if you listen to us through whatever platform. Please leave a review. We value the reviews because they helped to get the word out and bring more people on board. And it's good to see lots of newbies following space nuts who have messaged messaged us in recent months to say, hey, we new, we found you. We've started at the beginning. We'll catch up soon. You've only got four hundred and seventy to go. Yeah, that sounds me that number of episodes, it does. I know we've started doubling up not long ago, but yeah, it's still good numbers. Thank you, Fred. As always, you are a delight to speak with, so I'm told. Thanks Andrews, so are you so uncle? Speak to you soon? Thanks again? All right? So, yeah, Fred Watson, Astronomer at Large and someone else who's a delight to talk to whenever it turns up and it wasn't. Today is here in the studio and from me Andrew Dunkley. Thanks for your company. We'll catch you on the very next episode of Space Nuts. Bye Byeuts. You'll be listening 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.