Latest / Space Nuts: Astronomy Insights & Cosmic Discoveries / #402: Pergola Projections & Proxima Possibilities: Solar Shields and Exoplanetary Expeditions

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#402: Pergola Projections & Proxima Possibilities: Solar Shields and Exoplanetary Expeditions · Space Nuts: Astronomy Insights & Cosmic Discoveries

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Hi there, Andrew Dunkley here. Thanks for joining us on Space Nuts QDA.
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This is the separated second half of what used to be a big podcast,
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but we've decided to break it up because of audience feedback mainly, and
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that enables people to absorb the show smaller chunks, which seems to be much
0:22
more palatable for most. So we'll carry on with this and see how it
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goes. Coming up on this episode, we're going to be answering questions about
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Planet nine. We'll also be chasing up Rusty's solar pagola. Remember we talked
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about that a few weeks ago. Well, Rusty's come up with a follow
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up idea and David's got a what if question for us, which I've had
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to do some research on because I honestly couldn't answer it until I did some
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homework. And I hope Fred's got some homework too, but he might have
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a better idea than I have, and a bit of homework as well.
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Following up questions from Wayn and Wayne asked us about supernova supernov's causing gravitational waves,
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yes or no, and how insight is able to triangulate impact points of
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things hitting the planet's surface. Lee wanted to know about that, So we'll
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be doing all of that in this episode of Space Nuts Q and A right
1:25
now for fifteen seconds. Guidance is Internal ten nine Ignition, Space Nuts NI
1:34
four three two Space Nuts. As I reported, Bill's good and joining us
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again is Professor Fred Watson, Astronomer at Large. It's a coincidence spread that
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we're both still wearing the same shirts as we did in the last episode.
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I mean, I don't know how that happened. It just means we're pretty
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scruffy. Really, we're very rough around the edges in the mine's a Space
1:59
Nuts shirt by the way. Yeah, I'm going to have to drag mine
2:01
out because since we moved everything sort of in different places and I haven't really
2:07
gone looking for them. I know they're probably not far away. I know
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they're not in that wardrobe behind me that's just full of junk. Had to
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put it somewhere. Let's get stuck into it because we've got a few questions
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to deal with and a bit of homework to follow up. Our first question
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comes from a regular Duncans. Hello, s Duncan here from Wellmouth, Indorset.
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Just another quick question for you just wondering with the Planet nine episode and
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so far we've not been able to find it. Also with all the rogue
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planets that have been found recently, is it possible that in the past a
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rogue planet would have come through our Solar System, or at least near to
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it, and perturb the objects out in the York Cloud and the Kuiper Belt
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so that they present this strange orbit that they've got now, and that the
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road planet would have then gone on its way back out of our Solar system,
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and therefore there is no planet knowing to be found, but the objects
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still exhibit the strange orbit into which they were perturbed. Just thinking, you
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know, is that a possibility? So we're looking for something that might no
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longer be there. Okay, thank you anyway, and thanks for the good
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work and keep it up and all that. Thank you. Bye. All
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right, interesting idea. So possibly a rogue planet or something else passing by
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that caused some interference that created the anomalies that we now blame a planet on
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that may not be there. What are your thoughts? Yes, so that's
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all possible, that's all possible. Wow, But I think it's been basically
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eliminated by those people who are studying the orbits of these distant transptune union objects.
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They're called extreme transceptuny on objects, the ones whose orbits are aligned.
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So my feeling is that that, if I remember rightly, so, there
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were papers published on this in twenty sixteen and twenty seventeen. They were the
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kind of original proponent papers of the idea that there has been that there is
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another planet in the Solar System, co authored by Mike Brown, who's one
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of the main proponents of this. Now I if I remember rightly, those
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he's looked at, you know exactly these ideas that there have been more likely
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to be a passing star because the Sun does wander near stars as it meanders
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around the galaxy, and those stars do have a gravitational influence. We believe,
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for example that and this is not a star, this is something even
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bigger, a giant molecular cloud. But one of the theories that looked at
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the bombardment of the Earth by comets, done by colleague of mine in Edinburgh
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back in the day, they looked at the idea that giant molecular clouds had
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influenced the Oort Cloud and basically dumped comets into the inner Solar system, which
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meant that there were episodes of bombardment on the Earth, which they found evidence
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for. So, you know, it's an idea that is kind of well
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known in astronomy that the Sun is fairly lonely at the moment. The nearest
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star is proxima centaury four point three light years away, but they may well
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have been closer encounters throughout the history of the Sun. And I'm pretty sure
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that this sort of thing was looked at in those early papers. But if
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I may to segue to a new paper that's come out, and this is
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featured actually by our good friends at Universe Today, the Universe Today website.
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They I think have had a chat with Mike Brown, who is actually the
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Richard and Barbara Rosenberg professor of astronomy at Caltech, and he's certainly one of
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the main proponents of this. They've done some new research and they've narrowed down
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the area in which we should be looking, which you know, is really
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a step forward because the searches that have been carried out so far have been
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over a very wide area. I think they've narrowed it down. I can't
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remember to how many square degrees it is, but it's narrowed down. And
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this is in advance of the via SA Ruben telescope coming online, Andrew,
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which is going to be the world's most effective survey telescopes, and eight point
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four meter telescope that will look at the whole sky. Is it every three
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or four nights, the entire sky? Because it's a wide field telescope,
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and you know, the planet nine will be high on the agenda of objects
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to be looking for by that telescope. A couple of quotes, if I
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may from from Mike Brown, planet nine would be the fifth largest planet in
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the Solar System, and the only one with a mass between the Earth and
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Uranus. Such planets are common around other stars, and we would suddenly have
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a chance to study one in our own mess would be your legs, like
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Jordie likes, I'm not going to touch it, Andrew. Another another quote
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that I like, There are too many signs. This is Mike Brown again,
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there are too many signs that planet nine is there. The Solar System
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is very difficult to understand without planet nine, and he goes on to say
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again talking to universe today, planet nine explains many things about the orbits of
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objects in the outer Solar System that we would be otherwise unexplainable and would each
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need some sort of separate explanation. The cluster of the directions of the orbits
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is the best known, but there is also a large perihelium distances of many
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objects, existence of highly inclined and even retrograde objects. That's things that orbit
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the wrong way round clockwise are seen from above the North Pole. It's the
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wrong way round. And the high abundance of very eccentric orbits which cross inside
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the orbits of Neptune. None of these should happen in the Solar System,
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but are all easily explainable as an effect of planet nine. So Dr Brown
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is still very much the proponent of planet nine. And well, does planet
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nine exist? And we will find it in coming years and decades, as
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Universe today asks, only time will tell, and that's why we do the
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science. Yes. Indeed, although there was one theory that it may not
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be a planet but a cluster of staff, that cluster of stuff has been
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one. Clusters of stuff are very difficult to hold together, Andrew, and
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so it needs to be something solid. But a mini black hole has also
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been suggested, and that might be something that's more difficult to eliminate. Right,
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wow, Okay, there you go, Duncan. Great question and very
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timely given there some new information, So thanks for sending it in. And
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yeah, we continue our search for planet Night, not me personally. I'm
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going to leave that up to other people that you know occasionally take a peek
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us, Yeah, yeah, yeah, my three point five will find it.
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It's not three point five meters, it's three point five inches. But
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it's actually Michael, I don't know. I can't remember what size it Isn't
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that terrible? Thank you Duncan. Now we've got a follow up concept,
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let's call it from Rusty about his soular pagola, which he told us about
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a few weeks ago. This was aimed at reducing the Earth's exposure to the
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Sun by around two percent, and he sent us an email about it and
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he said, I'm afraid I gave you and Fred and Andrew the wrong idea.
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Although I briefly considered a megastructure at L one, rather foolishly thought calling
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the sunscreen I have in mind the solar pegola would garners in. It may
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have done that, but it also gave people the wrong idea. What I
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do have in mind is a constellation of starling proportions. Each satellite would throw
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a penumberal shadow on the Earth, and the total two percent sunscreen would not
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be noticeable. I'm convinced that using emerging technologies, we could have this done
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in ten years. What do you think of that? Friend? It's good
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stuff. And Duncan is Rusty. Sorry, Beggy, pardon Rusty, Sorry,
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Rusty, Sorry, I'm mixing up my listeners. All of them are
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a big fun of by the way. So yeah, but there's a lot
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going on in the you know, in the scientific world along similar lines.
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And in fact only was it a fortnights ago, three weeks ago as we
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stand now, there was a big article in the New York Times, and
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I think it was all have picked up in the Cinney Morning Hral entitled could
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a giant parasol in outer space help solve the climate crisis? Now, that's
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sort of a bit of a reference to the megastructure idea that Duncan, Sorry,
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Rusty, let me just write down Rusty was thinking about before. But
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that article was good because it pointed back to a lot of the earlier research
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that's been done on this, and indeed there's papers everywhere. One that I
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liked was goes back to scientists in the University of Hawaii who wrote a paper
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back in July last year about the idea of a sun umbrella. In other
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words, you know, a parasol tethered to an asteroid in order to give
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it some sort of stability. So once again it's a megastructure, but it's
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got an asteroid tethering it. But this is probably disappointment to Rusty. The
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one that essentially is identical to what Rusty is suggesting was written by somebody I
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know, actually a scientist called Roger Angel, who is a professor I think
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he might be now retired at the University of Arizona. He published a paper
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in the Proceedings of the National Academy of Science back on November fourteenth, two
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thousand and six, which is feasibility of cooling the Earth with a cloud of
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small spacecraft near the inner lagrange point L one, which I think is exactly
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what Rusty's suggesting. And I'd actually suggest to Rusti that you actually look at
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this paper. It's pretty easy to find pnas Proceedings of the National Academy of
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Science feasibility of cooling the Earth with a cloud of small spacecraft near the inner
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La Grande point, and he goes through the mathematics the stability of spacecraft at
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the Grande point because it is actually a gravitational sadde, which means they wander
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off if you don't if you don't do something about them. Let me just
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read a few things from his abstract. If it were to become apparent that
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dangerous changes in global climate were inevitable despite greenhouse gas controls, active methods to
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cool the Earth on an emergency basis might be desirable. The concept considered here
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is to block one point eight percent of the solar flux with a space sunshade
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orbited near the inner lagrange point L one in line between the Earth and the
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Sun. Following the work of Ja Early another Early if I mixed metaphors their
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worker on this back in nineteen eighty nine, he says transparent material would be
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used to deflect the sunlight rather than to absorb it to minimize the shifting balance
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out from L one caused by radiation pressure. So there are some real subtleties
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here. Andrew three advances aimed at practical implement presented. First is an optical
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design for a very thin refractive screen with low reflectivity, leading to a total
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sunshade mass of in the region of twenty million tons. Second is a concept
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aimed at reducing transportation costs to fifty dollars per kilogram by using electromagnetic acceleration to
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escape the Earth's gravity, followed by iron production propulsion. Some neat work there
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with basically with light sales, and third is an implementation of the sunshade as
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a cloud of many spacecraft autonomously stabilized by modulating solar radiation pressure. These met
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sized flyers will be assembled completely before launch, avoiding any need for construction or
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unfolding in space. They would weigh one gram each, be launched in stacks
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of eight hundred thousand, and remain for a projected lifetime of fifty years within
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a one hundred thousand kilometer long cloud. The concept builds on existing technologies.
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It seems feasa that it could be developed and deployed in a region in the
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region of twenty five years at the cost of a few trillion dollars less than
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point five percent of the world gross domestic product over that time. So Rusty's
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thinking is very much in line with what Roger Angel was proposing, except Rustina
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thinks we could get it down to ten years because of the new technologies that
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we have in space launch, and that might be absolutely right. Yeah,
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Look, we've got to do something because from what I've read about the progress
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we're making in dealing with the problem of global warming and climate change on Earth,
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we can't possibly do enough to alleviate the effect. And you know,
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not every country is conforming, so there needs to be another way. And
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maybe this is it. Just maybe I'm not a big fan of major geo
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engineering. But yeah, as you say, we really have to stay up
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on it in regard to what individual countries are doing. Plus increases our classification
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as a civilization and do it so he does for anybody who helps to be
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watching. Yes, well it's important, it's very important. Thank you,
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Rusty. Yes, we've now given you some homework, so have a look
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at that. Okay, well takes. Let's move on to our last question
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before we do our homework. This one comes from David. Hey, your
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friend Andrew, This is David from Singing Texas go one on favorite kinds of
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questions. What if if you could step foot onto any planet outside of our
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Solar system, which planet would it be? And why are you more interested
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in that planet than others? Thanks for all shell back, all right,
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David. Well, aside from Planet nine, which is, you know,
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we're not sure if it's part of our Solar system, but it's got to
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be. It's just so far out. I'll go first because I haven't got
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much to say that. I did a bit of homework on this, and
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I thought, loo, if we're going to step onto another planet, we
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really want to find a planet that's earth like. And that took me to
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the Kepler System, and the one that they think is most earth like,
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even though it's sixty percent larger than Earth, is Kepler four or five to
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two B, which I like the idea of until I read that it's probably
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got a run away greenhouse effect and it's developed more like Venus than Earth.
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But they reckon that is probably the most earth like planet so far that they've
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found outside our Solar System. I wouldn't mind having a look at that,
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setting foot on it might prove a challenge, though, But I mean,
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there's there's so many planets that they've discovered. Now most of them gas giants,
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so you know, you don't want to step on any of those.
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But any any rocky planet in a goldie Locks zone would probably be attractive to
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me. And Kepler four five two B is in the Goldilock zone, Fred,
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so maybe so, maybe so, But yeah, it is. It
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is a strange world compared to what we know, and the drawn the comparison
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to Venus, but it's probably it's in the Trappist One system, I think,
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discovered by the Kepler space telescope, So that one sort of jumps out
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at me. But I did have to do homework because I honestly I haven't
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really analyzed what we've learned about too many exoplanets, but it would have to
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be earth like and it would have to be in the Goldilocks zone. That's
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I'd want to have a look at any one of those. Really. Yeah,
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that's exactly the way my thinking went as well, Andrew. And I'm
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not sure the distance of the trappis One system, but I went for it's
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forty light years away. Yeah, Okay, so that's just too far for
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me. I'm getting old and I'm not sure I could. Yeah, so
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I'd be going to the nearest star Proxima Centauri four point three light years away,
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which has does have Proxima Centauri B, which I think is in Proxima
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Centauri's habitable zone. I don't think it's an Earth like planet, but it
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is within the habitable zone. And the problem with planets going around red dwarfs,
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which Proxima Centaury is, is that they're irradiated by the flares that these
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red dwarfs tend to emit from time to time. And so I'd have my
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radiation shield on full power, be sitting there watching what the effect of a
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solar flare, giantgantic solar flare is on this poor little planet around the nearest
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world. But what I'd have in the back of my mind is it's not
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too far to get back to Earth because it's only four point three light years.
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Yes, yes, you know, when we get our light speed engines
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or sort of out. Yeah, I'll do it. Yeah. It's still
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a long trip though, Isn't it all right? David? You are your
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what if question answered somewhat and thanks for sending it in Now to some homework.
21:34
We were asked recently by Wane whether or not a super and ova can
21:38
cause a gravitational wave. And the answer is it depends. Why did I
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know that? Yeah, so it depends on how symmetrical the explosion is.
21:52
In other words, if you know, if you've got a perfect explosion,
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everything goes outwards completely medially from the center, then you won't get a gravitational
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wave because all the acceleration accelerating masses are balanced, you know, it's balanced,
22:10
the ones going away from us balanced by the ones coming towards us,
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so you don't get one. But if he had an asymmetric Supernover explosion,
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and I think most of them probably are. I remember seeing some simulations years
22:22
ago of the gas dynamics of the Supernover explosion, and yeah, there's certainly
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looked as though there was a lot going one way and not quite as much
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going the other way. So that would give rise to a gravitational wave.
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Okay, there you go away. Yes, sometimes it's the problem with the
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answer. And Lee asked us about how insight on Mars was able to triangulate
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the impact point of meteorites and other things hitting the surface. We had to
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follow that up. We did, and I did that. I was going
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to, but you offered because I thought it was an interesting one. I
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kind of wondered the same thing myself. And you might remember, Andrew that
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I did waffle about the fact that seismic waves are not just you know,
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they're not just one uniform thing. They've got different frequencies, they've got different
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polarizations. There are sheer waves and what's the other pressure waves and sheer waves
23:23
the two different sorts. So and I think I think I might be sort
23:30
of have been vaguely on the right track. I'm going to read though,
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from someone's answer to the question this is on the Stack Exchange website. Question
23:45
was can we know where the mass quakes come from? An insight? And
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actually the question not read it out because it puts it exactly. When doing
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seismology on Earth, we use information from multiple stations to determine where a signal
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is coming from using triangulation. On Mars, we only have one seismomeitor insight.
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Is this enough to get a very rough idea of where the mass quake
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occurred? If so, how is it done? And the answer is from
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Okay, okay, it's from somebody I actually know. I've had dinner with
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him, Tom Spilker, who's Linda Spilker's other half, Tom is a space
24:23
engineer and very good space scientist, so I think we can we can take
24:27
this with some gravitars. I hadn't noticed that Tom was the author of this
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answer. So Tom's answer is according to this paper by the Inside Seismometter team.
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And this paper has a link to it so you can click on it.
24:45
It's the SIS team with a list of authors. As long as you
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are that sounds like tom techniques. Combining data about the arrival times of various
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modes of seismic waves, the amplitude or strength of the waves, and surface
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waves that travel around Mars's globe more than once can determine the location of Mars
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quakes. My reading of the paper this is Tom again, is that the
25:11
process isn't a straightforward calculation, but instead involves modeling of Mars's interior structure and
25:17
wave propagation characteristics, adjusting the models until the coherent solution is reached. That
25:22
solution includes the depth and geographic position of the quakes focus. So a great
25:27
answer, by what a delight to find who it's from, and that includes
25:33
impacts because just anything that causes the right kind of vibration or by modeling,
25:41
you can work out where it's come from. Fascinating. There you go,
25:44
Lee, that's how it's done. Now, don't forget. If you have
25:48
questions for us, please send them in via our website. Just click on
25:52
the AMA tab where you can send us a text question or an audio question.
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We actually have very few audio questions at the moment, so please get
26:00
them into us. You can also click on the thing on the right hand
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side, the greenish tearly sort of spinmint colored button send us your question,
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although when you hover on it at tur it's purple. And just as long
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don't forget to tell us who you are and where you're from. And while
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you're on our website, have a look around and see what you see.
26:27
Fred, thanks so much. We'll catch you on the next episode of Space
26:32
Nuts very very soon. Sounds great, Andrew, take care and talk to
26:36
okay, Professor Fred Watson, astronomer at large and here in the studio.
26:40
Who's got more editing to do than a Disney cartoonist person who does Disney stuff.
26:48
I don't know what they're called. Animator all right, I'm out of
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here thanks to your company. Catch you on the next episode of Space Nuts.
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