#402: Pergola Projections & Proxima Possibilities: Solar Shields and Exoplanetary Expeditions

Hi there, Andrew Dunkley here. Thanks for joining us on Space Nuts QDA. This is the separated second half of what used to be a big podcast, but we've decided to break it up because of audience feedback mainly, and that enables people to absorb the show smaller chunks, which seems to be much more palatable for most. So we'll carry on with this and see how it goes. Coming up on this episode, we're going to be answering questions about Planet nine. We'll also be chasing up Rusty's solar pagola. Remember we talked about that a few weeks ago. Well, Rusty's come up with a follow up idea and David's got a what if question for us, which I've had to do some research on because I honestly couldn't answer it until I did some homework. And I hope Fred's got some homework too, but he might have a better idea than I have, and a bit of homework as well. Following up questions from Wayn and Wayne asked us about supernova supernov's causing gravitational waves, yes or no, and how insight is able to triangulate impact points of things hitting the planet's surface. Lee wanted to know about that, So we'll be doing all of that in this episode of Space Nuts Q and A right now for fifteen seconds. Guidance is Internal ten nine Ignition, Space Nuts NI four three two Space Nuts. As I reported, Bill's good and joining us again is Professor Fred Watson, Astronomer at Large. It's a coincidence spread that we're both still wearing the same shirts as we did in the last episode. I mean, I don't know how that happened. It just means we're pretty scruffy. Really, we're very rough around the edges in the mine's a Space Nuts shirt by the way. Yeah, I'm going to have to drag mine out because since we moved everything sort of in different places and I haven't really gone looking for them. I know they're probably not far away. I know they're not in that wardrobe behind me that's just full of junk. Had to put it somewhere. Let's get stuck into it because we've got a few questions to deal with and a bit of homework to follow up. Our first question comes from a regular Duncans. Hello, s Duncan here from Wellmouth, Indorset. Just another quick question for you just wondering with the Planet nine episode and so far we've not been able to find it. Also with all the rogue planets that have been found recently, is it possible that in the past a rogue planet would have come through our Solar System, or at least near to it, and perturb the objects out in the York Cloud and the Kuiper Belt so that they present this strange orbit that they've got now, and that the road planet would have then gone on its way back out of our Solar system, and therefore there is no planet knowing to be found, but the objects still exhibit the strange orbit into which they were perturbed. Just thinking, you know, is that a possibility? So we're looking for something that might no longer be there. Okay, thank you anyway, and thanks for the good work and keep it up and all that. Thank you. Bye. All right, interesting idea. So possibly a rogue planet or something else passing by that caused some interference that created the anomalies that we now blame a planet on that may not be there. What are your thoughts? Yes, so that's all possible, that's all possible. Wow, But I think it's been basically eliminated by those people who are studying the orbits of these distant transptune union objects. They're called extreme transceptuny on objects, the ones whose orbits are aligned. So my feeling is that that, if I remember rightly, so, there were papers published on this in twenty sixteen and twenty seventeen. They were the kind of original proponent papers of the idea that there has been that there is another planet in the Solar System, co authored by Mike Brown, who's one of the main proponents of this. Now I if I remember rightly, those he's looked at, you know exactly these ideas that there have been more likely to be a passing star because the Sun does wander near stars as it meanders around the galaxy, and those stars do have a gravitational influence. We believe, for example that and this is not a star, this is something even bigger, a giant molecular cloud. But one of the theories that looked at the bombardment of the Earth by comets, done by colleague of mine in Edinburgh back in the day, they looked at the idea that giant molecular clouds had influenced the Oort Cloud and basically dumped comets into the inner Solar system, which meant that there were episodes of bombardment on the Earth, which they found evidence for. So, you know, it's an idea that is kind of well known in astronomy that the Sun is fairly lonely at the moment. The nearest star is proxima centaury four point three light years away, but they may well have been closer encounters throughout the history of the Sun. And I'm pretty sure that this sort of thing was looked at in those early papers. But if I may to segue to a new paper that's come out, and this is featured actually by our good friends at Universe Today, the Universe Today website. They I think have had a chat with Mike Brown, who is actually the Richard and Barbara Rosenberg professor of astronomy at Caltech, and he's certainly one of the main proponents of this. They've done some new research and they've narrowed down the area in which we should be looking, which you know, is really a step forward because the searches that have been carried out so far have been over a very wide area. I think they've narrowed it down. I can't remember to how many square degrees it is, but it's narrowed down. And this is in advance of the via SA Ruben telescope coming online, Andrew, which is going to be the world's most effective survey telescopes, and eight point four meter telescope that will look at the whole sky. Is it every three or four nights, the entire sky? Because it's a wide field telescope, and you know, the planet nine will be high on the agenda of objects to be looking for by that telescope. A couple of quotes, if I may from from Mike Brown, planet nine would be the fifth largest planet in the Solar System, and the only one with a mass between the Earth and Uranus. Such planets are common around other stars, and we would suddenly have a chance to study one in our own mess would be your legs, like Jordie likes, I'm not going to touch it, Andrew. Another another quote that I like, There are too many signs. This is Mike Brown again, there are too many signs that planet nine is there. The Solar System is very difficult to understand without planet nine, and he goes on to say again talking to universe today, planet nine explains many things about the orbits of objects in the outer Solar System that we would be otherwise unexplainable and would each need some sort of separate explanation. The cluster of the directions of the orbits is the best known, but there is also a large perihelium distances of many objects, existence of highly inclined and even retrograde objects. That's things that orbit the wrong way round clockwise are seen from above the North Pole. It's the wrong way round. And the high abundance of very eccentric orbits which cross inside the orbits of Neptune. None of these should happen in the Solar System, but are all easily explainable as an effect of planet nine. So Dr Brown is still very much the proponent of planet nine. And well, does planet nine exist? And we will find it in coming years and decades, as Universe today asks, only time will tell, and that's why we do the science. Yes. Indeed, although there was one theory that it may not be a planet but a cluster of staff, that cluster of stuff has been one. Clusters of stuff are very difficult to hold together, Andrew, and so it needs to be something solid. But a mini black hole has also been suggested, and that might be something that's more difficult to eliminate. Right, wow, Okay, there you go, Duncan. Great question and very timely given there some new information, So thanks for sending it in. And yeah, we continue our search for planet Night, not me personally. I'm going to leave that up to other people that you know occasionally take a peek us, Yeah, yeah, yeah, my three point five will find it. It's not three point five meters, it's three point five inches. But it's actually Michael, I don't know. I can't remember what size it Isn't that terrible? Thank you Duncan. Now we've got a follow up concept, let's call it from Rusty about his soular pagola, which he told us about a few weeks ago. This was aimed at reducing the Earth's exposure to the Sun by around two percent, and he sent us an email about it and he said, I'm afraid I gave you and Fred and Andrew the wrong idea. Although I briefly considered a megastructure at L one, rather foolishly thought calling the sunscreen I have in mind the solar pegola would garners in. It may have done that, but it also gave people the wrong idea. What I do have in mind is a constellation of starling proportions. Each satellite would throw a penumberal shadow on the Earth, and the total two percent sunscreen would not be noticeable. I'm convinced that using emerging technologies, we could have this done in ten years. What do you think of that? Friend? It's good stuff. And Duncan is Rusty. Sorry, Beggy, pardon Rusty, Sorry, Rusty, Sorry, I'm mixing up my listeners. All of them are a big fun of by the way. So yeah, but there's a lot going on in the you know, in the scientific world along similar lines. And in fact only was it a fortnights ago, three weeks ago as we stand now, there was a big article in the New York Times, and I think it was all have picked up in the Cinney Morning Hral entitled could a giant parasol in outer space help solve the climate crisis? Now, that's sort of a bit of a reference to the megastructure idea that Duncan, Sorry, Rusty, let me just write down Rusty was thinking about before. But that article was good because it pointed back to a lot of the earlier research that's been done on this, and indeed there's papers everywhere. One that I liked was goes back to scientists in the University of Hawaii who wrote a paper back in July last year about the idea of a sun umbrella. In other words, you know, a parasol tethered to an asteroid in order to give it some sort of stability. So once again it's a megastructure, but it's got an asteroid tethering it. But this is probably disappointment to Rusty. The one that essentially is identical to what Rusty is suggesting was written by somebody I know, actually a scientist called Roger Angel, who is a professor I think he might be now retired at the University of Arizona. He published a paper in the Proceedings of the National Academy of Science back on November fourteenth, two thousand and six, which is feasibility of cooling the Earth with a cloud of small spacecraft near the inner lagrange point L one, which I think is exactly what Rusty's suggesting. And I'd actually suggest to Rusti that you actually look at this paper. It's pretty easy to find pnas Proceedings of the National Academy of Science feasibility of cooling the Earth with a cloud of small spacecraft near the inner La Grande point, and he goes through the mathematics the stability of spacecraft at the Grande point because it is actually a gravitational sadde, which means they wander off if you don't if you don't do something about them. Let me just read a few things from his abstract. If it were to become apparent that dangerous changes in global climate were inevitable despite greenhouse gas controls, active methods to cool the Earth on an emergency basis might be desirable. The concept considered here is to block one point eight percent of the solar flux with a space sunshade orbited near the inner lagrange point L one in line between the Earth and the Sun. Following the work of Ja Early another Early if I mixed metaphors their worker on this back in nineteen eighty nine, he says transparent material would be used to deflect the sunlight rather than to absorb it to minimize the shifting balance out from L one caused by radiation pressure. So there are some real subtleties here. Andrew three advances aimed at practical implement presented. First is an optical design for a very thin refractive screen with low reflectivity, leading to a total sunshade mass of in the region of twenty million tons. Second is a concept aimed at reducing transportation costs to fifty dollars per kilogram by using electromagnetic acceleration to escape the Earth's gravity, followed by iron production propulsion. Some neat work there with basically with light sales, and third is an implementation of the sunshade as a cloud of many spacecraft autonomously stabilized by modulating solar radiation pressure. These met sized flyers will be assembled completely before launch, avoiding any need for construction or unfolding in space. They would weigh one gram each, be launched in stacks of eight hundred thousand, and remain for a projected lifetime of fifty years within a one hundred thousand kilometer long cloud. The concept builds on existing technologies. It seems feasa that it could be developed and deployed in a region in the region of twenty five years at the cost of a few trillion dollars less than point five percent of the world gross domestic product over that time. So Rusty's thinking is very much in line with what Roger Angel was proposing, except Rustina thinks we could get it down to ten years because of the new technologies that we have in space launch, and that might be absolutely right. Yeah, Look, we've got to do something because from what I've read about the progress we're making in dealing with the problem of global warming and climate change on Earth, we can't possibly do enough to alleviate the effect. And you know, not every country is conforming, so there needs to be another way. And maybe this is it. Just maybe I'm not a big fan of major geo engineering. But yeah, as you say, we really have to stay up on it in regard to what individual countries are doing. Plus increases our classification as a civilization and do it so he does for anybody who helps to be watching. Yes, well it's important, it's very important. Thank you, Rusty. Yes, we've now given you some homework, so have a look at that. Okay, well takes. Let's move on to our last question before we do our homework. This one comes from David. Hey, your friend Andrew, This is David from Singing Texas go one on favorite kinds of questions. What if if you could step foot onto any planet outside of our Solar system, which planet would it be? And why are you more interested in that planet than others? Thanks for all shell back, all right, David. Well, aside from Planet nine, which is, you know, we're not sure if it's part of our Solar system, but it's got to be. It's just so far out. I'll go first because I haven't got much to say that. I did a bit of homework on this, and I thought, loo, if we're going to step onto another planet, we really want to find a planet that's earth like. And that took me to the Kepler System, and the one that they think is most earth like, even though it's sixty percent larger than Earth, is Kepler four or five to two B, which I like the idea of until I read that it's probably got a run away greenhouse effect and it's developed more like Venus than Earth. But they reckon that is probably the most earth like planet so far that they've found outside our Solar System. I wouldn't mind having a look at that, setting foot on it might prove a challenge, though, But I mean, there's there's so many planets that they've discovered. Now most of them gas giants, so you know, you don't want to step on any of those. But any any rocky planet in a goldie Locks zone would probably be attractive to me. And Kepler four five two B is in the Goldilock zone, Fred, so maybe so, maybe so, But yeah, it is. It is a strange world compared to what we know, and the drawn the comparison to Venus, but it's probably it's in the Trappist One system, I think, discovered by the Kepler space telescope, So that one sort of jumps out at me. But I did have to do homework because I honestly I haven't really analyzed what we've learned about too many exoplanets, but it would have to be earth like and it would have to be in the Goldilocks zone. That's I'd want to have a look at any one of those. Really. Yeah, that's exactly the way my thinking went as well, Andrew. And I'm not sure the distance of the trappis One system, but I went for it's forty light years away. Yeah, Okay, so that's just too far for me. I'm getting old and I'm not sure I could. Yeah, so I'd be going to the nearest star Proxima Centauri four point three light years away, which has does have Proxima Centauri B, which I think is in Proxima Centauri's habitable zone. I don't think it's an Earth like planet, but it is within the habitable zone. And the problem with planets going around red dwarfs, which Proxima Centaury is, is that they're irradiated by the flares that these red dwarfs tend to emit from time to time. And so I'd have my radiation shield on full power, be sitting there watching what the effect of a solar flare, giantgantic solar flare is on this poor little planet around the nearest world. But what I'd have in the back of my mind is it's not too far to get back to Earth because it's only four point three light years. Yes, yes, you know, when we get our light speed engines or sort of out. Yeah, I'll do it. Yeah. It's still a long trip though, Isn't it all right? David? You are your what if question answered somewhat and thanks for sending it in Now to some homework. We were asked recently by Wane whether or not a super and ova can cause a gravitational wave. And the answer is it depends. Why did I know that? Yeah, so it depends on how symmetrical the explosion is. In other words, if you know, if you've got a perfect explosion, everything goes outwards completely medially from the center, then you won't get a gravitational wave because all the acceleration accelerating masses are balanced, you know, it's balanced, the ones going away from us balanced by the ones coming towards us, so you don't get one. But if he had an asymmetric Supernover explosion, and I think most of them probably are. I remember seeing some simulations years ago of the gas dynamics of the Supernover explosion, and yeah, there's certainly looked as though there was a lot going one way and not quite as much going the other way. So that would give rise to a gravitational wave. Okay, there you go away. Yes, sometimes it's the problem with the answer. And Lee asked us about how insight on Mars was able to triangulate the impact point of meteorites and other things hitting the surface. We had to follow that up. We did, and I did that. I was going to, but you offered because I thought it was an interesting one. I kind of wondered the same thing myself. And you might remember, Andrew that I did waffle about the fact that seismic waves are not just you know, they're not just one uniform thing. They've got different frequencies, they've got different polarizations. There are sheer waves and what's the other pressure waves and sheer waves the two different sorts. So and I think I think I might be sort of have been vaguely on the right track. I'm going to read though, from someone's answer to the question this is on the Stack Exchange website. Question was can we know where the mass quakes come from? An insight? And actually the question not read it out because it puts it exactly. When doing seismology on Earth, we use information from multiple stations to determine where a signal is coming from using triangulation. On Mars, we only have one seismomeitor insight. Is this enough to get a very rough idea of where the mass quake occurred? If so, how is it done? And the answer is from Okay, okay, it's from somebody I actually know. I've had dinner with him, Tom Spilker, who's Linda Spilker's other half, Tom is a space engineer and very good space scientist, so I think we can we can take this with some gravitars. I hadn't noticed that Tom was the author of this answer. So Tom's answer is according to this paper by the Inside Seismometter team. And this paper has a link to it so you can click on it. It's the SIS team with a list of authors. As long as you are that sounds like tom techniques. Combining data about the arrival times of various modes of seismic waves, the amplitude or strength of the waves, and surface waves that travel around Mars's globe more than once can determine the location of Mars quakes. My reading of the paper this is Tom again, is that the process isn't a straightforward calculation, but instead involves modeling of Mars's interior structure and wave propagation characteristics, adjusting the models until the coherent solution is reached. That solution includes the depth and geographic position of the quakes focus. So a great answer, by what a delight to find who it's from, and that includes impacts because just anything that causes the right kind of vibration or by modeling, you can work out where it's come from. Fascinating. There you go, Lee, that's how it's done. Now, don't forget. If you have questions for us, please send them in via our website. Just click on the AMA tab where you can send us a text question or an audio question. We actually have very few audio questions at the moment, so please get them into us. You can also click on the thing on the right hand side, the greenish tearly sort of spinmint colored button send us your question, although when you hover on it at tur it's purple. And just as long as you've got a device with microphone, you can record your message. And don't forget to tell us who you are and where you're from. And while you're on our website, have a look around and see what you see. Fred, thanks so much. We'll catch you on the next episode of Space Nuts very very soon. Sounds great, Andrew, take care and talk to okay, Professor Fred Watson, astronomer at large and here in the studio. Who's got more editing to do than a Disney cartoonist person who does Disney stuff. I don't know what they're called. Animator all right, I'm out of here thanks to your company. Catch you on the next episode of Space Nuts. Bye bye. You'll be listening to the Space Snot's 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.