May 25, 2023

#353: Exploring the Cosmos: Saturn's Record-Breaking Moon Count & Other Space News

#353: Exploring the Cosmos: Saturn's Record-Breaking Moon Count & Other Space News

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In this episode of the Space Nuts podcast, I discuss the recent discovery of 62 new moons orbiting Saturn using a telescope. As a space enthusiast, I am excited to learn about this fascinating discovery, which brings the total known moons around Saturn to 145, surpassing Jupiter's 95 moons. I am intrigued by the method used to discover the small satellites, as the cameras on spacecraft Cassini were not capable of identifying them. Professor Fred Watson explains that the distinction between what constitutes a moon is based on its size, composition and orbit. This episode provides an engaging and educational discussion on the latest space science news and developments. As a host, I recommend this episode to anyone who wants to stay updated on recent discoveries.
In this episode, you will be able to:
· Explore the impressive discovery of 62 new moons around Saturn through telescopic advancements. · Delve into the awe-inspiring gamma-ray burst, the universe's largest recorded explosion.
· Gain insights on asteroid protection methods like gravity tractors and kinetic impactors.
· Discuss the inaccuracies in Martian agriculture depicted in popular movies.
· Contemplate the ethical dilemmas and potential hazards of utilizing nuclear weapons in outer space.
#astronomy #space #science #news #spacetime #podcast




AI Transcript

ANDREW DUNKLEY: Hello there. Andrew Dunkley here, the host of Space Nuts. Nice to have your company once again and again and again, we won't go into that. Hope you're well, stick around because we've got a lot coming up on this episode and that includes, Saturn doing a bit of a moon at us, multiple moons, in fact, also the largest cosmic explosion yet seen.

ANDREW DUNKLEY: We will also be answering audience questions about black holes.

ANDREW DUNKLEY: Yep. Asteroid redirection and Paul's got an issue with the Martian movie. We'll find out about all of that and more on this episode of Space Nuts.

4324334554321 Space Nuts. Astronauts report. It feels good.

ANDREW DUNKLEY: And joining me as always is Professor Fred. What's an astronomer at large? Hi, Fred.

FRED WATSON: Hi, Andrew. How, how are you? Sorry? You just disappeared for a minute. How are you again?

FRED WATSON: Yeah, but you came back. That's right. We've had the wonderful disappearing act this morning. It's been crazy, hasn't it?

ANDREW DUNKLEY: I am well, I am really well and you likewise.

FRED WATSON: Oh, good. Very well. And you know, always always happy to wake up in the morning and find that nothing's dropped off. Or there you go with a certain age and you'll get that don't fast approaching.

ANDREW DUNKLEY: I, I think most people have sort of seen as plodding along over the last five weeks or so and, you know, business as usual. But the fact is we haven't seen any, each other for five weeks because we've both been away doing these various things. You've been chasing eclipses. I've been, swimming around Alaska, thanks to a boat and, and Canada and taking in the sights. It's been wonderful.

FRED WATSON: Indeed. You've, I know you've had a great time as indeed did. I, we had a wonderful view of the, sorry, the April 20th eclipse off the coast of western Australia and a marvelous tour around Arnhem Land and Kakadu, which was very, very, I, I can imagine even this time extremely interesting.

ANDREW DUNKLEY: It's a toasty part of the world. I, I, I'll tell you about a few Space related things that happened while I was away. First thing in Calgary, we went to a restaurant called Major Tom, which, they gave us that, it, it's named after the, Space Oddity song by David Bowie, but it's been named, Calgary's Top Restaurant for the last two years running.

ANDREW DUNKLEY: And we had, the Canadian National dish. What while we were there, which is rather lovely. It's just a sort of the Canadian take on chips with stuff on it. But it's a bit more, a bit more advanced than, chips with gravy. Like we have. I tried to look at the northern lights while we were up around Alaska.

ANDREW DUNKLEY: There were a couple of nights where it was really active, but, I missed it for two reasons. I think I looked at the wrong time and possibly the wrong direction and, the next night it was raining. So that was disappointing. But when we were in Jasper, I ran across a couple of young people who were standing over behind a counter at the reception of the accommodation we stayed at and they run the Jasper Planetarium.

ANDREW DUNKLEY: And so a big shout out to Jerry and Kaylene, I spoke to them for a few minutes. I'd had a couple of wines, so I'm not sure I made much sense. But there it is the Jasper Planetarium.

ANDREW DUNKLEY: So if you're ever in Jasper go and check it out, they've got a website Jasper Planetarium dot com. So, yeah, worth worth having a chat to them. They're lovely people. And it was really enjoyable to catch up and I told them all about Space Nuts. So they've certainly committed to not listening. And, yeah, I went to the Space needle in Seattle. I've even got a Seattle hat.

ANDREW DUNKLEY: I always get a, I always get a cap wherever I go.

ANDREW DUNKLEY: So, the Space needle is amazing. Built in 1962 63 for the World's Fair. As was our hotel built for the World's Fair, which was the edge water where the Beatles famously got a photo taken hanging out the window of their hotel fishing.


ANDREW DUNKLEY: And I got a photo of that photo.

ANDREW DUNKLEY: So that's, that's my journey in a nutshell.

FRED WATSON: It was really fabulous.

ANDREW DUNKLEY: Few people might have caught some of the pictures on Facebook because I did share them. Let us get stuck into it because we're under the gun. And first up Satin has reclaimed its title as the biggest mooner in the solar system. Naughty, Naughty Satin.

FRED WATSON: That's right. It's this is a story that I have to say Andrew that this really surprised me when when I saw it because the headline is, well, one of the headlines, excuse me, Saturn reclaims its title of Moon King with the discovery of 62 new moons orbiting the planet bringing the total to 100 to 100 and 45. Now, now, you know, for was it 13 years?

FRED WATSON: We had a marvelous spacecraft in orbit around Saturn that had some very sensitive cameras and did Sterling work on our understanding of the planet and its rings and its moons. And I would have thought that if there were any small undiscovered moons lurking around in around Saturn, Cassini, the name of the spacecraft would have found them.

FRED WATSON: And that is why it took me quite by surprise. In fact, I'll be honest with you, it took my breath away. 62 moons. How does that work when we've had a spacecraft patrolling around Saturn? And maybe just because maybe Linda Spilker is listening, who is the project scientist for for Cassini and a, and a good friend.

FRED WATSON: The, the problem with the spacecraft like Cassini is that it's, it's got all these really high resolution cameras, it does have some wide field cameras, but it can't look at everything at once. And so the science that it was doing was targeted towards understanding the rings, understanding all the other bits of course, We got marvelous photographs of all of those things Saturn its moons, everything.

FRED WATSON: And remember Caroline Poco, she was the image scientist for Cassini and became very celebrated as somebody who's produced some of the most marvelous images in the solar system, but it can't look everywhere at once.

FRED WATSON: And, and that's actually why our good friend, Trevor Barry over there in Broken Hill became world famous, an amateur astronomer who was able to look at Saturn with his his telescope in Broken Hill and, and alert the Cassini team to storms and other things of interest like that. Now, so, so I, I guess in that regard, Cassini is absolved from any responsibility for missing the 62 moons.

FRED WATSON: But the, the other thing that I was really impressed by was the way in which these moons have been discovered because they were discovered not by a spacecraft in orbit around Saturn, not by the James Webb Space telescope, not by some Fancy piece of kit somewhere but a telescope not very different from our own Anglo Australian telescope here in New South Wales.

FRED WATSON: And it is the 3.6 m Canada France, Hawaii telescope, which has got a nice Canadian flavor to it. Yes, that's right. Maple. It's a team that it is actually led by scientists from Taiwan. And what they did was they used the telescope to essentially not track on the stars, which is what you do when you're taking a photograph of the stars, you actually get the telescope to track at the same rate at which the Earth is turning.

FRED WATSON: So that you, you pick up images of stars as dots points of light because usually your exposures might be 15, 20 minutes, sometimes an hour to build up the faint light on your image sensor. Much different from taking a picture with your mobile phone where it's kind of instantaneous.

FRED WATSON: It's this is long exposure photography. And so what would happen if you did that? And there was a moon of Saturn in the field of view, that moon has got its own motion. And so it's moving against the background of the stars. And that means that the light that falls on the detector is constantly shifting across the detector.

FRED WATSON: And so it just is too faint to be picked up. So what these scientists did was to calculate how they could move the telescope. So it would pick up the motion of typical moons around Saturn. And that's how they got the 62 as yet unseen moons, which are, I don't think they're very big.

FRED WATSON: I think they're a order a kilometer or so in size, tiny little worlds, which may have originated possibly in a collision between bigger moons that is essentially you know, demolished something else to make lots and lots and lots of smaller moons. And, and one reason they think that might be the case is because several of these moons have got similar orbits.

FRED WATSON: They're, they're moving in paths around Saturn that have kind of similarities suggesting that they might have come from the same impact event. It seems unlikely that they were formed with Saturn itself because they're in orbits that are very different from, you know, from the like the rings and the, and the, the moons that sit in the ring.

ANDREW DUNKLEY: So that may well answer my question as to how you differentiate a moon around Saturn from the rubble that we know of as the rings. So obviously it comes down to size, constitution it orbit and, and orbit.

FRED WATSON: That's right. So, I mean, the, you know, the thing about the rings is, yes, you're right. There, there are millions of what you might call little moon letts in the rings because they are chunks of ice up to, up to about 10 m, I think in size. But there, but there are moons that sit within the rings and these are much bigger objects that actually sit in the ring system.

FRED WATSON: And the in fact, some of the, it's because of the moons in the ring system that you get gaps in the rings as well. There's this sort of gravitational interaction between these things which were all these were beautifully captured by images from Cassini. So I think the objects that we're talking about now are in very different orbits.

FRED WATSON: I can't remember the details, but some of them are quite a long way from Saturn, but they're definitely in orbit around Saturn, they've been tracked over a long enough period of time that you can see that they're actually circulating around the planet and not just random asteroids that are in the same field of view.

ANDREW DUNKLEY: Do they have to be a certain size to be considered a moon or do they just have to be a rock in orbit?

FRED WATSON: That's a good question because, you know, what I've just said that some of the chunks of ice in, in Saturn's rings are maybe 10 m across. You might want to call that a moon because it's, you know, it's a sizable object.

FRED WATSON: But I think the probably that the, if I can put it this way, the, the, the, the, the categorization of what constitutes a moon, is probably something that is, that's distinguishable as a single entity, which these tiny chunks of rock around in the rings aren't.

FRED WATSON: So, I I, and of course, you can do that either by its size or by its orbit or as you said, by its composition, if it turned out to be rocky, which the rings aren't that they've got a lot of dust in them, but they're not rocky.

FRED WATSON: So, yeah, there must be a, an I A U International Astronomical Union definition of what a moon is. And I'm sure in the case of Saturn it's one that they've had to work hard on so that they don't include the ring particles as moons.

FRED WATSON: So anyway, that could get very messy. It would be messy indeed. So what we're left with is a new value for the number of moons around Saturn, which makes my book spacewalk completely out of date. Now, it's gone up to 100 and 45 which contrasts with Jupiter, which I think is 95 at the moment.

ANDREW DUNKLEY: It's in the nineties. I remember that does this suggest perhaps Fred that there are going to be more moons to be discovered around Saturn and Jupiter?

FRED WATSON: It's, it's possible Andrew. And you, you might think. Well, yes, Jupiter's nearer. So they should be easier to find if there are any tiny objects of this kind in orbit around, in orbit around Jupiter.

FRED WATSON: But just bearing in mind that these 62 newly discovered moons of Saturn, quite a significant fraction of them are thought to be the result of a single collision, where, you know, maybe two bigger moons have collided and blown and destroyed themselves, resulted in many, many fragments.

FRED WATSON: So that's a particular event and Jupiter might not have had things like that happening in its past so that, you know, we we we may be at a stage there that there really is very little left to discover around the around Jupiter in terms of moons.

ANDREW DUNKLEY: Well, I guess it it remains to be seen but yeah, it's, it's a fabulous discovery and Saturn regained regains its title. Of course, if you want to see more moons than that, just go down the main street of Dubbo on a Saturday night.

FRED WATSON: Yepy of new moons there, if you make it sound very attractive.

ANDREW DUNKLEY: And this is Space Nuts with Andrew Dunkley and Professor Fred Watson.

ANDREW DUNKLEY: This episode of Space Nuts is brought to you by Curiosity Stream. Now, I'm sure you've heard my brother Steve in the last few weeks mentioning our love of documentary documentaries growing up. I, I certainly remember 12 noon Sunday switching the TV on to watch National Geographic and Jacques Cousteau and all of those amazing people who went out to learn about things that helped me learn about the world.

ANDREW DUNKLEY: Well, Curiosity Stream is just that it is the very best place for you to go and watch documentaries and they cover a myriad of subjects, technology, nature, travel, history, science. And that includes the exclusivity cur. Curiosity Stream has exclusive award winning films and shows that you can't watch anywhere else.

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ANDREW DUNKLEY: I'll be checking out military history. I can tell you that that's one of my favorite subjects. And yes, as I also mentioned, they add new shows every week. So check it out. It is called Curiosity Stream. And as a Space Nuts listener, you get 25% off.

ANDREW DUNKLEY: Just use the promo code Space Nuts when you log on to Curiosity Stream dot com slash Space Nuts, Curiosity Stream dot com slash Space Nuts and use the promo code Space Nuts for unlimited access to some of the world's top top documentaries and non fiction series all available to you as a Space Nuts listener. And thanks again to Curiosity Stream for sponsoring today's episode.

ANDREW DUNKLEY: Let's Fred move on to our next topic and I think we can get one of our audience members to introduce this one. This is, this is Russ.

SPEAKER 5: Hi, friend Andrew. It's Russ here from Stow Bridge in Birmingham, the UK. Love the show guys. I was just wondering if there was any update on the gamma ray burst known as the boat, the biggest of all time that we detected last month And there seemed to be some evidence of super high energy particles that we detected that could potentially explain what dark matter is.

SPEAKER 5: I haven't heard anything about it since so I was just wondering if you could give us an update. Thanks a lot guys. Take care.

ANDREW DUNKLEY: Goodbye. Thank you, Russ. It's coincidental that Russ should send that question in because Fred had put it on the topic list for us for this week before I knew the question had arise. So he's right on the money. The largest cosmic explosion yet seen, not the brightest but the biggest.

FRED WATSON: Yeah, actually, we are talking about two different things here.

ANDREW DUNKLEY: He said both though.

FRED WATSON: Yes, but this is not the book. This is one that beats the boat into.

ANDREW DUNKLEY: Well, we can talk about both.

FRED WATSON: We should talk about both books. Yeah.

FRED WATSON: So I, I forgot, I beg your pardon. I forgot what, what's the that gentleman's name there?

FRED WATSON: Ross. Thank you, Ross. Ross is he's on the money in that. We're seeing some very bright events. The the gamma ray burst that Russ is talking about nickname Boat for Brightest of all time that took place last October or it was detected last October.

FRED WATSON: But it was a gamma ray burst. It was a brief flash of gamma radiation. I don't know because I didn't pick up on the details there. I had time to look at this since you've only just raised it again.

FRED WATSON: It's I don't know whether there was an optical counterpart found what that means is finding a visible light equivalent and I hadn't heard about the implications for dark matter. So, thanks Ross for the heads up on that. We might, I will follow up on that. Absolutely. We'll do that. Try to do that for next, for next time. That's a good thing.

ANDREW DUNKLEY: I made that blunder because they're both being called boats.

FRED WATSON: Well, this one's called 82 oh 21 L W X which is not spelled B O N T but biggest of all time would actually be, was brightest of all time. I know. So this might be the biggest of all time. You could be, right? Because it is, that's the, exactly what, how, how it's being portrayed now just coming back to Earth if we can. I might read you the title of the paper in which these results were published.

FRED WATSON: It begins, we present observations from x-ray to MDI infrared wavelengths of the most energetic non quasar transient ever observed. So a transient is is something where there's radiation which usually comes and goes, which is what, where the transient term comes from, but this has come and has not yet gone. It, it's an explosion that has been taking place for the last three years.

FRED WATSON: Basically, it was an event that was spotted actually again by a telescope in California. That has similarities with one of the telescopes that we have here at Siding Spring Observatory in New South Wales, not the Anglo Australian telescope, which I mentioned a few minutes ago, but the United Kingdom Schmidt telescope, which I used to work on in very great detail back in the seventies sorry eighties and nineties.

FRED WATSON: So there is a telescope in California that is almost identical. In fact, our Schmidt telescope was a copy of it. Effectively. There were mods made. This thing is now called the Z Vicky Transient Facility. And it's on the Ocean Schmidt telescope at Mount Palamar. And that basically is used to record the sky over repeatedly over, you know, relatively short time intervals to look for things that come and go.

FRED WATSON: And so that might include supernovae exploding stars. It might include asteroids. I think they churn out many asteroids discoveries in their, in their work. But back in 2020 the telescope was doing its usual automated sky sweep and it picked up this bright object which shot people because when they followed it up, they discovered that it was I think it's eight billion light years away.

FRED WATSON: Yeah, exactly. It's a long, long way off. And that meant that the, the, basically the, the energy that they were recording is very, very high. And one of the lead authors of this work, Philip Wiseman who's at the University Of Southampton in the UK. He made the comment that the the, the estimate for its brightness is wait for it two trillion times brighter than the sun.

FRED WATSON: Yeah. And so, you know, what is it? Well, what they've done very wisely is followed up in wavelengths as it said from x-rays up to up to mid infrared.

FRED WATSON: And that rules out some of the possibilities is by doing that, that you find out that it's eight billion light years away because you, you measure its red shift. And so, it's really an extraordinary object. And the, the sheer energy of what it's putting out rules out the possibility of it being a supernova, a, a an exploding star because it's 10 times brighter.

FRED WATSON: And with supernovae exploding stars, they generally come up to peak brightness. There are many different kinds of supernovae. So they all behave slightly differently, but they usually fade within a matter of days or weeks after that peak brightness. This thing is kind of still going, it's actually it has started fading, but it's, it's fade is very gradual.

FRED WATSON: It's occupying hundreds of days. The best bet that they have in terms of interpreting what it is is OK. You start with the most energetic objects we know about which are black holes. So a supermassive black hole in the center of a galaxy which incidentally they can't see. So that's weird as well.

FRED WATSON: But if you've got a supermassive black hole with a disc of material around it, that as, as we know, because we've talked about this many times, this stuff swirls around is raised to very high energies by the friction that's caused during this swirling around. It's called the accretion disk. And then some of it disappears into the black hole, some of it gets shot out by magnetic fields.

FRED WATSON: But the bottom line is you get a lot of energy coming from these things and that's what we normally call a quasar, an outburst in the center of a galaxy that comes from material being sucked in, but they are variable on much shorter timescales than this one. And so the interpretation is that yes, this is the scenario, you've got a supermassive black hole stuff swirling around it.

FRED WATSON: But what has actually gone into this disc of swirling material is a very, very large, what we call a giant molecular cloud, a cloud of gas, basically. And that they, in fact, they, I'll just read the last sentence of the abstract of, of the paper by Philip Wiseman at it says a plausible scenario is the accretion of a giant molecular cloud by a dormant black hole.

FRED WATSON: In other words, one that's not been doing too much before that of 10 to the 8 to 10 to the nth solar masses. That's the size of the, that's the size of the black hole. It's of the order of a billion solar masses. And so you've got a large cloud of gas that is so big that it takes a long time for the black hole to gobble it up.

FRED WATSON: They, they make the comment 80 21 2021 L W X thus represents an extreme extension of the known scenarios of black hole accretion. In other words, it is really a one off and that's why it is a record holder.

ANDREW DUNKLEY: Extraordinary. Yeah, that's a huge, huge boom.

ANDREW DUNKLEY: I, I guess they'll do some more study and try and confirm their theories. That's what you do, I suppose and maybe we'll know in the future exactly what happened.

FRED WATSON: Yeah, that's right. I mean, what we, what we're seeing at the moment is we've got what are called light curves here which are still being produced. And a light curve of this object showing how it's increased in brightness and its increase was relatively relatively general.

FRED WATSON: It took something like 100 days to, to get from not being visible at all up to the kind of brightness that it has now. So it's a gentle increase but is now being followed by an even more gentle decrease in brightness. So these are all measurements of what we call its magnitude. It's it's, it's brightness like.

FRED WATSON: Yeah, that's, that's right, unlike most, you know, most supernovae which are more like what we used to call a banger, but here it is called a banger.

FRED WATSON: Yes, indeed.

ANDREW DUNKLEY: Right. There'll probably be more to come on that particular story. This is Space Nuts. Andrew Dunkley with Professor Fred Watson.

ANDREW DUNKLEY: Let's take a quick break from the show to talk about our sponsor Nord VPN, which I know you know about because we've been talking about it for a long time. And with very good reason, it is the best virtual private network available. And as a Space Nuts listener, you get a special deal including a 30 day money back guarantee.

ANDREW DUNKLEY: All you have to do is log on to the special URL that is set up for Space Nuts listeners and click on, get the deal to find out all about it nor to VPN dot com slash Space Nuts, which I'll repeat shortly. I've just come back from Overseas as you're probably aware.

ANDREW DUNKLEY: We were in Canada and Alaska and we used a lot, a great deal of public wi-fi while we were away, airports, hotels, motels, eateries, you name it. And I had my Nord VPN set up to automatically connect regardless of what I was doing or where I was from and it made me feel very, very safe. Indeed. Not only that I had seamless connectivity.

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ANDREW DUNKLEY: So click on, get the deal on the URL Nord VPN dot com slash slash Space Nuts. That's Nord VPN dot com slash Space Nuts. Look at the options available. I've got the complete package for two years, which gives me extra time on top of that as part of the deal.

ANDREW DUNKLEY: But you, you can go through and find out exactly what you need and choose the plan accordingly. I'm sure you won't be disappointed Nord VPN dot com slash Space Nuts. Now, back to the show Space Nuts. Now, Fred, let's get into the Q and A session where we handed over to the audience to come up with some questions for us. And the first one comes from Clyde.

SPEAKER 6: Hi, Fred Andrew. It's Clive from England. Thanks so much for the show. I love it. I'm an avid follower.

SPEAKER 6: Fred said something very interesting in the last episode, which is about black holes made from dark matter. And it struck me that wouldn't, as far as I can guess, be any difference between a black hole made of dark matter and a black hole made of ordinary matter.

SPEAKER 6: So, does that imply that black hole? Well, are they the same first? And does it imply that black holes could be hoovering up dark matter as well as ordinary matter? I'd love to know what you think about that. It's a great conjecture by Fred. So, thank you very much. Cheers.

ANDREW DUNKLEY: Thank you, Clyde. Dark matter and black hole questions are not uncommon and here we, here we've put the two together and both, which is great actually.

FRED WATSON: And I kind of in some ways ties in with that paper we discussed recently that also says that dark energy might be due to black holes that, you know, maybe maybe black holes are really the secret of everything. All the big questions that we've got, the only one that they might not answer is, are we alone? Anyway, Yeah.

FRED WATSON: So that's, you know, your thinking along those lines is interesting because I think, I think you're right that given that the, the phenomenon about, excuse me, the phenomenon about dark matter that reveals its dark matter is its Gravitation and Gravitation is all you need to make a black hole. So that's a Beatles song, isn't it?

ANDREW DUNKLEY: Gravitation is all you need.

FRED WATSON: Yeah. Gravitation. Gravitation is all You need a hit song in 1967. I remember it. Well, yeah.

FRED WATSON: And of course it winds up with, I think it's in the mood. It's one of the old, the old swing band songs that comes in at the end there as well as she loves you. Yeah. Yeah, that's gravitationally anyway. I forgot where we got to.

FRED WATSON: Yeah, that yes. So the Gravitation All right, Gravitation is what generates a black hole. And yes, why not have dark matter in black holes? I really need to follow up on this because there will be work on it in the, in the literature.

FRED WATSON: You know, is there any reason why we don't think that dark matter is swallowed up by black holes? And does that mean that, you know the in the gravitational gravitational potential? Well, that is a black hole, there's a mixture of normal and dark matter, which kind of makes sense because there's a mixture of it outside black holes as well.

FRED WATSON: In fact, we know it's here and there where you are. It's where the normal matter is. Great question and let me follow up again on that and see whether we can get some answers on it.

ANDREW DUNKLEY: Thank you, Clyde couldn't come up with all the answers today, but we're talking black holes and dark matter. So there's still a lot of unanswered questions regarding that and dark energy. Of course, let's go now to Mikey.

SPEAKER 3: Hey, Fred and Andrew, it's Mikey from Illinois.

SPEAKER 3: So a while back now you guys had an episode on asteroid redirection and asteroid threats and how we would avoid such things. And you guys had mentioned nuclear bombs, you know, could be an option.

SPEAKER 3: And it got me thinking and I've been thinking about it ever since and I've been meaning to ask you guys this but time, time just gets away from you. But if we did have to send a nuclear bomb on a rocket to destroy an asteroid that was too big to redirect or you know, whatnot.

SPEAKER 3: Rockets fail. And unfortunately, we've seen this before in the past and it got me wondering what happens if a rocket fails with a nuke strap to it when we're trying to redirect an asteroid or destroy an asteroid in this case.

SPEAKER 3: I guess there's just always that potential and I had never thought about it. I mean, am I right in this and that, you know, there could be a rocket failure in a scenario like this. And then what happens here on Earth? I mean, I guess it would depend on how big the nuke is.

SPEAKER 3: I mean, what kind of destruction would we be looking at? Am I? Am I thinking right? Like that is definitely a possibility, just a quick, what if you know that never crossed my mind and, I hope you guys have a good one. Enjoy the podcast. Thank you.

ANDREW DUNKLEY: Oh, Mikey got cut off. But thank you, Mikey and thank you for putting that terrible nightmare into my brain.

ANDREW DUNKLEY: First and foremost, if we were to put a nuke on a rocket, I wouldn't be contracting Elon Musk to send it up at the moment. But, yeah, the rockets fail. It's, it's a fact of life and, most don't, but you don't really want one carrying something like this to fail. But Fred, I would suspect that the way they make nuclear weapons, there are lots of fail safes built in.

FRED WATSON: Yeah, I think that's true. Andrew.

ANDREW DUNKLEY: And so notwithstanding the possibility of it cracking open in the, that's right, the nuclear released some other way.

FRED WATSON: So, so a number of points to pick up on here, one is just, just, I don't often leap to Elon's defense.

FRED WATSON: I mean, his whole philosophy of making reliable rockets is to test by failure.

FRED WATSON: And it's a different scenario from the way NASA works. But he can do it because he's not using public money. Well, he is to some extent, but you know what I mean? It's a private company. And so the, you know, the spectacular failure on the 20th of April of the star ship, the first starship flight, which failed because of a fault in the second stage, separating from the first.

FRED WATSON: It wasn't actually the rocket itself blew up. It failed to separate and so that produced an instability and they had to destroy the rocket. But Elon will take stuff from that and learn from it and, you know, hopefully next time it'll have a better outcome.

ANDREW DUNKLEY: Now, look, I was, it was tongue in cheek, but I do have a lot of respect for him. And absolutely, I just said that it wasn't until I was in Canada and Alaska that I saw why he's got so much money to pour into rockets because the number of Teslas on the road is outstanding. Amazing.

FRED WATSON: That's great everywhere. It's great news. I mean, you know, that's why we respect Elon for exactly those reasons. We've got all these electric cars, we've got reusable spacecraft. It is amazing. There's other things that we don't quite feel so respectful about.

FRED WATSON: That's right. Anyway, but you're right. You know, rockets, you've got, what you've got is a, you've got a, a bomb sitting there with something very precious on top of it, whether that's a human or a nuclear warhead. So you, you, you're always running risks.

FRED WATSON: I think the bottom line is though, and it, and it is possible that we might need nuclear weapons, not actually to, to demolish an asteroid, but to deflect it. By the shock wave the blast, you, you explode the, the device next to it and the shock wave actually pushes the asteroid or accelerates it slightly.

FRED WATSON: And you and I covered this story probably a few months ago where it turns out that rubble pile asteroids are actually more resilient to that kind of thing. You think they would be because you think they just fought a bit, but they actually apparently would be easier to deflect and that's something that will feed into the whole idea of planetary protection.

FRED WATSON: So I, I think the, you know, the crux of the matter here is that you would only be doing that in extremists. You would only think about sending nuclear weapons into Space because it kind of contravenes the, you know, international Space Law effectively.

FRED WATSON: You would only do it if that was the only way to avoid an impact by an asteroid down the track, which might result in much higher loss of life than a nuclear explosion on a, on a launch pad.

ANDREW DUNKLEY: But we're talking bureaucrats here, we want to send a nuclear weapon into Space to deflect an asteroid that is going to destroy humanity. No, you can't do it. It says so right there.

FRED WATSON: Well, that's, that, that's right then that might be the answer in the end.

FRED WATSON: But, but it, it, it would have to be literally the only possible option. I think that's right.

ANDREW DUNKLEY: But for the rocket failing with a nuclear weapon on board, the bombs are designed not to explode if there's a disaster. But whether or not the cataclysmic explosion or whatever it is that brings the rocket down causes the nuclear warhead to crack open and expose us to radiation. That's another matter.

FRED WATSON: Yes, that's right.

FRED WATSON: It is. And, and those are all possible scenarios. You, you're absolutely right. So, Mike has raised an interesting, you know, it's almost a philosophical or sort of an ethical question really about whether we should, whether we should do that is, is the risk worth the reward.

FRED WATSON: And I think that will be the equation that would have to be sorted out by. Yes, the bureaucrats and anybody else who's involved with it, that's the other option.

ANDREW DUNKLEY: And we can't do it now, but we could just build the bomb in Space and launch it from beyond our atmosphere.

FRED WATSON: Perhaps that might, that might also be possible. That's, that's a good suggestion. I mean, I don't know, centrifuge uranium, centrifuges in Space to refine uranium. That sounds like the sort of thing that would also raise hackles.

FRED WATSON: You know, I think you'd need to be in a, in a scenario where the world was united in realizing that this was the only way to deflect this asteroid and avoid a, a catastrophe because otherwise you'd have, like, you know, the committee that I was involved with in the beginning of the year. Cock the committee on the peaceful uses of Outer Space. Yes.

FRED WATSON: Sending a nuclear weapon to an asteroid is part of the peaceful uses of outer Space. But is not, it's, sorry, I'm just gonna do that. It's not, something that would normally be thought of as a peaceful venture to send a nuclear rocket into Space and sorry, a nuclear missile into Space.

ANDREW DUNKLEY: Indeed. Good question Mikey and very interesting to discuss and maybe we'll get to talk more on it in the future. Finally, Fred, we've had questions about the movie, The Martian several times and discussed some of the feasibility of the things they portrayed in that film, including growing potatoes on the moon. Paul has an observation.

SPEAKER 7: Good day. Professor Fred and Andrew. This is Paul from Sunny Bridge Vegas in Queensland Australia. I have a question about that awesome movie, The Margin.

SPEAKER 7: There is one thing that has been battling me and it's this at the start of the movie, there's the Space ship that's being threatened by this huge dust storm and these, you know, we're not in Kansas anymore. Toto wins that are gonna knock it over.

SPEAKER 7: So the astronauts have to get on board and leave Mattie Damon in the, you know what quite literally, I get the impression that that's just not gonna happen because Mars' atmosphere is what 2% of Earth.

SPEAKER 7: So there's very little air pressure and the winds just can't push over anything that heavy, let alone the rovers that are already on there, am I? Right? And, if I am right, is that ok? It's not like they were making a movie like Star Trek or Star Wars, which is more like, you know, Space opera rather than science fiction.

SPEAKER 7: So, are they doing to scientists and science a little bit of a deer disservice by, fudging things like that, when they try and get everything else. Right. I don't know. It's probably nothing but nevertheless, I just thought it was food for thought. So, keep up the excellent work, gentlemen. And have a good one. Thank you.

ANDREW DUNKLEY: Thank you, Paul. It's a, it's a great question and it brings up another element that I had trouble with and that was, at the end of the film, his rescue where he had to drive 3000 miles to get to another, rocket ship to take him off the planet, which they'd already deployed on the planet. Which didn't make sense to me.

ANDREW DUNKLEY: How can you already deploy, an Earth return vehicle when there was nobody to return? And they've got a, no, it didn't, it didn't gel. It was just sort of a throw away. Oh, we better figure out a way to get a rocket to him. Well, let's already have it there. So that part of the story I thought was a bit iffy.

ANDREW DUNKLEY: But yes, the storms on Mars, they can be quite volatile though. Can't they, Fred?

FRED WATSON: Yes, they're certainly, they're capable of producing global dust storms which tells you that they're significant. Paul is absolutely right though, the pressure is low. It's actually 0.6% of Earth's atmospheric pressure.

FRED WATSON: The reason why we can get global dust storms blown up by winds in such a rarified atmosphere is that the dust is very fine. It's extremely fine, very easy to, to lift up. We've got these dust devils that we see on Mars, little whirlwinds.

FRED WATSON: So, but Paul is absolutely right, you know, winds even though they might be quite high speed, but with, within an atmosphere that thin, are not going to knock over solid pieces of steel or titanium or whatever it is.

FRED WATSON: So the, the, the, the, the, the, their wins. But I, I think, I think Paul's right that, you know, that scenario wouldn't happen.

FRED WATSON: There were a lot of, there were a lot of other things, the one thing that bothered me about the Martian and it's along the same lines if I remember rightly, there was a bit where he had a, almost like a tent or something which had a hole in it which he patched up with the sheet of, of, oh, that was, that was in the habitat where he was growing potatoes and the, the entry way the, airlock blew off and he patched it up with plastic, but wasn't it the outside that it touched the plastic on the, on the, what was the opening to the, the air lock and patched it up with plastic and, and tied it down?

FRED WATSON: I mean, it's, it's essentially a vacuum out there. So that bit of plastic would have bulged and probably burst, just by virtue of the atmospheric pressure within it. So that upset me a bit and you were clearly upset by the logic of having a spacecraft to conveniently ready to take him home.

ANDREW DUNKLEY: I mean, so you've got to take a little bit of latitude in creating the story. A lot of it was well researched and they did a fabulous job and the growing of potatoes angle actually would work.

FRED WATSON: Yes. So we, so we're here. So, but Paul's, you know, Paul's bigger question is the philosophy of, of of how you portray as science fiction or a Space opera type scenario, whether, whether we are playing to something completely fictional or whether we're a mixture of both, which I guess the Martian was a bit like the movie Gravity. That was a mixture of fact and fiction.

ANDREW DUNKLEY: I think it had a lot more creative license added to it than the Martian. Some of some of the stuff they pulled off. There was probably, you know, one in a trillion chance of surviving scenarios and she did it four times.

FRED WATSON: But the one that, and I always come back to this one, the one that stuck with the physics, at least for the first, I guess, 80% of the movie was, was 2001 a Space Odyssey because that, that everything that was in there was feasible.

FRED WATSON: And it was only at the end where we went off into, you know, a different dimension of Space time, courtesy of the aliens. And that was the bit that, and it didn't worry me at all in that because I accepted the fact that, yeah, we're, we're in new territory here.

ANDREW DUNKLEY: So we can't, you know, that movie was actually one of the options on my flight was from Canada and I was going to watch it, but I fell asleep, which, which was good. I actually slept, coming home.

ANDREW DUNKLEY: I slept for seven hours and tricked my brain into thinking I was still in western Canadian time and when I woke up it was, early morning in Sydney and I was in sync. So I actually managed to trick my brain into avoiding jet lag this time around.

ANDREW DUNKLEY: Well done. Yeah, seven hours sleep on a plane in a 15 hour flight. I was very impressed. I've never done that before. Probably never will again.

ANDREW DUNKLEY: Thank you, Paul. That was a great question. And, you were right. Yes, the, the storms up there would not knock the rocket over. And the other thing I noticed is, because you said that the storms only have min, you know, minor dust particles. They were, this one was lifting up rocks. Yes.

ANDREW DUNKLEY: Like the size of a, a coin type of thing. So, that was a bit of a misnomer as well. Fred, that wraps it up. Don't forget if you've got questions for us. Please send them to us via our website, Space Nuts podcast dot com or Space Nuts dot I O and you can, send text and audio questions that way and don't forget to have a look around while you're there.

ANDREW DUNKLEY: And, if you want to think about becoming a patron of Space Nuts, by all means, look into that as well. We'll never force you to pay for it. But, if you want to voluntarily put some money in the kitty to pay for a new internet connection or something, that, would be most welcome.

ANDREW DUNKLEY: Yes, we've had a fun time today.

ANDREW DUNKLEY: Yeah. And, thanks to Hugh back in the studio. As always, he's had five weeks off and of course, today he thought he was still having time off and that's probably why we dropped out five or six times during the recording. Fred as always. Thank you. We'll catch you next week.

FRED WATSON: Sounds great. Andrew. I look forward to it. Good to see you back again and I love the cup.

ANDREW DUNKLEY: Oh, Yes, I do too. It's a nice color and I love Seattle. What a beautiful city, beautiful city. See you soon.

FRED WATSON: Fred, take care.

ANDREW DUNKLEY: Bye for now, Fred Watson astronomer at large part of the overwhelmingly large team of three here at Space Nuts. And for me, Andrew Dunkley. Thanks for your company. Catch you on the very next episode.

Bye bye to the Space available at Apple Podcasts, Google Podcasts, Spotify, Iheart Radio or your favorite podcast player. You can also stream on demand at bites dot com.

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