Mars Gullies Aren't Made by Water: The Surprising Dry Ice Answer

0:00Andrew Dunkley Hello. Thanks for joining us. This is Space

0:02 Nuts. A fresh, crisp episode for you to devour, I hope. My name is Andrew Dunkley. Uh, your host. Great to have your company. Uh, a bit of a water theme in this particular episode, or partly. There's a question being raised in, uh, space science about what causes the gullies on Mars. Well, we know that gullies are caused by, uh, water flows and rainfall on Earth. But, um, that can't be the case on Mars. Or can it? They think they've figured it out and it's quite a surprising thing.

0:36 Uh, we're also going to look at water on the moon, or the lack of which could threaten future cities and the search for ocean worlds. They think they know how. We'll tell you all about it on this episode of space nuts.

0:49Generic 15 seconds. Guidance is internal.

0:52 10, 9, ignition sequence.

0:55Professor Fred Watson Star space nuts.

0:56Generic 5, 4, 3, 2, 1, 2, 3, 4,

0:59 5, 5, 4, 3, 2', 1.

1:01Andrew Dunkley Space nuts.

1:02Generic Astronau. But it feels good.

1:05Andrew Dunkley To help us with all of that is Professor

1:07 Fred Watson Watson, Astronomer Large, sporting his new knee because he wanted to be needed.

1:17Professor Fred Watson Oh, uh, dear. That's all

1:20 right. Um, that's, uh, that's as good as they get today.

1:25Andrew Dunkley I think it's, you know, that's. That's dad

1:27 joke. Yeah, that's just beyond a dad joke. That's. That's weird.

1:34Professor Fred Watson So it was three, three weeks ago yesterday

1:37 that I got my new knee. So progress is happening. I am walking pretty well now. Um, I have yet to have my first drive in the car, but that'll be this week, I think. I'm told that I'm allowed to do that now. I'm off the high, um, intensity medication. Uh, and, uh, so far, so good. There was a bad week last week when things took a turn for the worse, uh, because I had an allergic reaction to the dressings that were on the knee. That can be quite dangerous, it turns out. They didn't tell me that until after they'd fixed the problem. Um, so, yeah, anyway, so it's all good. Everybody's happy at the moment.

2:17Generic Yeah.

2:18Andrew Dunkley Uh, the only downside is you've got the

2:20 hybrid knee, which means every night you've got to plug it in to charge it.

2:25Professor Fred Watson A bionic knee would be good for that. You

2:27 could perhaps get up to speed a bit faster than I do at the moment, but no, it's working very well. All credit to the team who did the job. Dr. Parker and his friends and stuff. Uh, we had a great. We had a great time. I.

2:40Andrew Dunkley It reminds me of Something my son told me

2:42 about because he's always online looking for the next weirdest thing. And he said, um, the Chinese, I think the Chinese have invented, uh, an exoskeleton that you can wear that will walk for you so you don't have to make the effort.

2:56Professor Fred Watson Yeah, yeah. And run.

2:59Andrew Dunkley Oh my goodness.

3:00Professor Fred Watson Yeah, they're good.

3:01Andrew Dunkley Isn't technology going in strange places,

3:04 directions?

3:05Professor Fred Watson That's right, yes.

3:05Andrew Dunkley But that, that I think is going to be great

3:08 for people in the future who are um, uh, have paralysis problems or.

3:12Professor Fred Watson Yeah. Profoundly disabled. That's right.

3:14Andrew Dunkley Sort of thing.

3:15Professor Fred Watson Mhm.

3:15Andrew Dunkley And probably good for rehabilitation. Who

3:18 knows?

3:19Professor Fred Watson Maybe. Yeah, maybe.

3:21Andrew Dunkley All right, uh, let's uh, talk about these

3:24 storeys that are in the news at the moment. And the um, the focus is on Mars in terms of uh, uh, images of Martian Gul. Now a lot of things about Mars are so strikingly similar to Earth. The canyons and the, and the ocean beds and all that. The only thing lacking is well, you know, a breathable atmosphere, liquid water on the surface, weather, uh, etc. Gravity, um.

3:51 But the question has come up as to what causes the gullies on Mars. Now my first thought was well hang on a minute, they were already there. I mean they happened billions of years ago and that was when water was liquid on the surface. But they've been changing without water. So what's going on?

4:11Professor Fred Watson Uh, indeed, that is a good

4:14 question. So um, probably you and I spoke about um, gullies on Mars a long time ago because there was a time when uh, it was being suggested that some of these gullies were due to the fact that on the equator on Mars in the Martian summertime you can actually get temperatures that are high enough for liquid water to exist. And the theory was that maybe, you know, there's a permafrost of uh, ice that come mid summer it melts and you get these water flows down slopes which are uh, what cause the gullies. Gullies I guess they're, you know, they're the beginnings of rivers really in a way. They're the sort of little gentle impressions in a landscape which are made by flowing water which always wants to go

5:05 downhill. Uh, and eventually you carve out a river valley. Um, but as you say, uh, some of the early observations, I think with Mars Reconnaissance Orbiter, with Mars Express, um, those two venerable orbiting uh, spacecraft, it was quickly realised that these things change on a seasonal basis. And that was why uh, the thinking was that maybe there's uh, enough water to do it. However, um, it turns out that you get these gullies in regions of Mars where the temperature never gets high enough for liquid water to exist on the surface. In other words the, you know, the higher latitude regions, the regions towards the poles. And so what has happened is that a group of scientists actually in uh, one of the

5:50 Parisian uh universities in France, uh, they've looked at the alternatives for water. So ruling out water you uh, can do it uh, because there's that we know what the temperature is, we know what the pressure is, uh, it's just not possible for liquid water to exist uh in some of these regions. But they did actually go even a step further. They uh, looked um, uh, from the data from Mars Express and Mars Reconnaissance Orbiter, they looked at the spectrum of some of these uh, at melting ice fields where you're looking really near the poles, ah of Mars where some of these gullies are. And they found um, there's no signature for water in uh, other words, water ice is definitely not ah, a player or liquid water is definitely

6:45 not a player, um, in this storey. And so the alternative which we know is present on Mars and we know that at least some of Mars's polar ice caps are made of this is uh, solid carbon dioxide or carbon dioxide generally. We on Earth are familiar with solid carbon dioxide as dry ice. Uh, uh, on Mars it does exist.

7:11 We know there's a frost of dry ice near the poles. Uh but because the pressure is lower on Mars, um, it's got slightly different uh mechanisms of behaviour. Uh so uh, it is possible for dryas, dry ice and Earth just sublimes. It goes straight from a solid to a gas. But I think under certain conditions on Mars it can be a liquid for a short time. So uh, what's the storey? These researchers uh had two theories uh which were to try and explain the origin uh of the gullies. Uh one is something which is um, a geyser, um, mechanism. The idea is you've got geysers which we're familiar with as jets of hot water uh, coming up from uh, underneath the surface of Earth being heated by magmatic heat.

8:08 I think both of us, you and I, Andrew, have been to the place that gives those things their name. Geysir in Iceland did visit the guys there.

8:17Andrew Dunkley Oh yeah, yeah, yeah. Actually the best one

8:20 I've ever seen was in New Zealand.

8:22Professor Fred Watson Yeah, at Rotorua.

8:25Andrew Dunkley Wow.

8:25Professor Fred Watson Rotorua, that's right, yeah. Uh, so

8:28 anyway, um, we don't call them Rotoruas, we call them geysers. That's because of the one In Iceland. So what's the theory there? The theory is that um, you've got basically a sheet of, of dry ice of solid carbon dioxide that forms in the wintertime. And as spring comes, the heat passing through that sheet of dry ice, uh, basically warms up the soil underneath and that turns some of the ice, this carbon dioxide ice, into gaseous carbon dioxide. So you've got a buildup of pressure underneath the sheet of ice and eventually the ice basically ruptures bang and out comes this high velocity jet of carbon dioxide. Um, and the theory is that that takes a lot of soil and uh, you know, dust and stuff with it and that

9:28 gives you, gives rise to the gullies. It gives you the, basically the discoloration that we see in the gullies. Uh, and that is a mechanism that they looked at. But uh, what has caused them to discard that idea is that the geyser action would appear um, around the spring equinox on Mars. Ah, but you don't see this gully activity, these darkenings of the gullies until later in the year. You don't see them until getting on almost for the Martian summer when those geysers should have shut down. So they ruled that out as the origin. Um, and this is the uh, start of what they looked at instead, which is something a bit similar. But rather than an sort of explosive process with the carbon dioxide sort of, you know, bursting out from

10:34 underneath these sheets of dry ice, uh, what you've got is the idea that there are, there are small, um, there aren't, you know, there might be small cracks in the ice but there's nothing big. But what happens instead of the gas bursting out through a large crack in the ice, the gas stays underneath the sheet of ice but kind of lubricates it, uh, uh, so that you've got essentially a floating sheet of dry ice and of course gravity takes over so it slides down the slope and actually can cause the appearance of these gullies. Uh, and so uh, that's their current favourite theory for how these gullies uh, form. And their modelling shows that in the end what you've got uh, is exactly what we see in uh the

11:28 gullies on Mars. Uh, and they make a comment um, that Earth, uh, like features don't always require Earth like physics. I think that might actually be a comment from Universe Today, uh, which is where this article comes from. An old friend of ours, Univers, uh, uh, uh, with Fraser Cain and others, uh, um, involved with that. So no liquid water on Mars. But uh, dry ice gullies perhaps?

11:53Andrew Dunkley Yeah. I like the way they

11:56 describe it for people like me to get into our heads what might be going on. They call it the air hockey effect.

12:03Professor Fred Watson Yes.

12:03Generic Ah.

12:03Andrew Dunkley If anyone's ever been to an arcade and played

12:06 air hockey, it's um, it's played on a table with lots of little pinholes in it blowing air up, uh, which causes a disc to be able to hover when you hit it. And that's, that's what they think might be the effect that's changing and causing the gullies on Mars. So really fascinating, really fascinating. Um, the other effect is um, is comparing a human bodily function. It's not as big and powerful as a trumpet, but it could be a silent but deadly.

12:40Professor Fred Watson I'm going to leave that one completely alone,

12:42 Andrew.

12:43Andrew Dunkley Just leave that one hanging in the

12:44Professor Fred Watson air Fred Watson, as you would, yes.

12:47 I'm afraid we've got a dog that does that. You don't see that side of Jordy's personality. Um, but we do.

12:54Andrew Dunkley Hearing, hearing him's enough.

12:56Professor Fred Watson Yes it is. Yeah, yeah. Oh, uh,

12:59 gosh.

12:59Andrew Dunkley But uh, no, it's fascinating and if you want

13:02 to read about IT, universetoday, uh.com is the website where you'll find that very interesting storey. This is Space Nuts with Andrew Dunkley and Professor Fred Watson Watson.

13:15Generic 0G and I feel fine.

13:17Andrew Dunkley Space Nuts, our uh, next storey takes us from

13:20 not water on Mars to a particular lack of water on the moon. And the reason they're saying that is because of um, you know, the potential for people living long term on the lunar surface. And up until now they've thought well there's a ready supply of water, everything will be fine, we can build a million person city there and um, yeah, it'll be great. Uh, now they don't think that's the case. They don't think there's nearly enough water to sustain uh, even a small city on uh, on the moon. So what's um, what's going on there, Fred Watson? And there's Earth.

13:59Professor Fred Watson Yeah, Earth just making a comment there. Um,

14:02 so thank you Jordan. Yeah, uh, very tiring. Yeah. One day we'll, I hope he'll end up on the moon. So yes, that we've got. And look the whole, it's really interesting the extent to which our explanation, you know, our exploration of the moon in terms of human landing is focused on this idea of there being copious water uh, on the moon. Uh, I'm doing a talk this weekend uh, at Macquarie uh, University. I'm their Keynote speaker for their open astronomy night, which I'm very honoured to be doing.

14:39 Um, and it's. My talk's about the future of Artemis and uh, other ventures to the Moon. And it all focuses on the southern polar region of the Moon where uh, there is a cluster of quite deep craters which never see sunlight, uh, because they're at the south pole. Um, the sun always misses their depths. Uh, some of them are quite deep. The one actually at the south pole, which is called Shackleton Crater, that's four kilometres deep, it's 20 kilometres across. Um, and uh, the evidence from previous space missions is that there is water ice in the base of these craters that may be billions of years old. Andrew because, uh, it's never seen the sun, so it's never been, you know, warmed up enough to turn into a

15:33 gas. And the temperature in some of these craters is extremely low, um, minus 200 or thereabouts. So it's frozen solid. So, um, we've got this whole focus now on getting um, spacecraft and humans eventually with Artemis 4, hopefully, uh, early in 2028, uh, actually landing on the Moon in this region. Uh, and it's quite a hazardous thing to do because the south pole of the Moon is very mountainous. It's got all these craters. It's not smooth, uh, sailing in terms of finding nice, um, flat places to land, as happened with the Apollo missions, which were all in much less challenging parts of the Moon's surf. So the focus on water on the Moon is enormous and uh, I don't know that it's really been

16:26 looked at in great detail before, but we now have some work that suggests that, uh, yes, there probably is water on the Moon's surface, but, uh, there might not be enough of it to make it, um, you know, uh, available on an industrial scale, if I can put that. A place where humans could survive, uh, permanently or where you could have permanent presence.

16:55 So it's um, a theory that really I think will start, uh, you know, raising a few eyebrows. Um, uh, it's come from, I guess, um, the idea of uh, just how much water there is there, um, you know, on the basis of the geography, if I can put it that way, the fact that you have got these deep craters, um, I, I uh, think the jury is still out on, on um, uh, just how much water there is, what form it takes, because it, you know, it could be buried under, under rock.

17:37 Uh, we're really in a, in a region of um, very big unansw and um, I don't think we've Talked about this, uh, Andrew, but um, Chang' E7 which is a Chinese ah, mission to land, uh, very near Shackleton Crater, actually the one I've just mentioned, uh, which was supposed to launch, actually I think the day before my knee operation it was supposed to launch but it was cancelled at very short notice with a fairly brief note from the China uh, space Agency, uh, and uh, that now looks as though it won't happen till 2027. But that spacecraft carried uh, not just a rover, there's an orbiter, a rover and a lander of course, but also a hopper, a little vehicle that will hop into craters rather than try and go down

18:32 into craters on wheels. And that's um, the idea is to use that hopper, uh, to try and find the water chang' uh e7 when it is launched, might be the first we know of, uh, you know, first, first hand, um, experience, if I can put it that way, of what the water is like in these craters. Sadly uh, we're going to have to wait a bit longer than we thought we did. But uh, that's one step forward.

18:57 And the hopper by the way is unlike anything that NASA is planning for the Artemis mission. So really interesting area. Uh, we, I think we're still groping in the dark a bit, if I can put it that way, given that these craters are definitely in the dark about just how much water there is. But it's possible that there might not be enough to make it that uh, well worthwhile.

19:19Andrew Dunkley Yeah, I suppose you've got to consider the

19:21 limitations in our capacity to look for it. At the moment they've only got the ability to look to shallow depths. So there could be water uh, deeper in the Moon's, um. Yes, yes, that, that we haven't found. So there may be more. But based on what we know now, putting a um, a city on the moon for you know, hundreds of thousands of people, it's just not feasible.

19:51 It wouldn't uh, it wouldn't last. I think they said it wouldn't last a year.

19:55Professor Fred Watson Yeah.

19:55Andrew Dunkley Based on the resources that exist on current

19:58 estimates, I couldn't imagine that many people living on the Moon, can you?

20:05Professor Fred Watson No, not really. Uh, I think um,

20:08 it's not a place you'd want to. I can imagine there being things like the outpost we have in Antarctica. I think that's a sort of reasonably sustainable model for exploring the Moon. But yeah, cities of tens of thousands of people I think is a non starter and this perhaps underlines that. That's, I guess the point uh, of

20:31Andrew Dunkley the article, uh, they do

20:34 go on to say that, um, a village of a thousand, maybe ten thousand people would last centuries though, if they kept the numbers down. So, um, the resources that exist at the moment are feasible to an extent.

20:49Professor Fred Watson Yes.

20:51Andrew Dunkley Um, and you

20:54 also have to bring into play things like recycling, uh, of water. Uh, they use recycled water on the International Space Station and I think it's got over 98 efficiency. You'd have to do that on the moon, otherwise you're going to go through it like a packet of salt and quite.

21:14Professor Fred Watson And.

21:15Andrew Dunkley And then you've got a real problem. The only

21:17 other way of dealing with it, well, two ways would be to transport water from Earth. But do we really want to do that? Uh, or harvest it. Harvest it from somewhere else.

21:28Professor Fred Watson That's the whole point of going to the moon.

21:31 Uh, and of course, this water is not just for keeping a city running, it's to act as rocket fuel for future, uh, exploration beyond the moon. So that's one of the appealing features about it. Yeah, very interesting. Um, and, uh, it does beg the question as to whether strategies will change dramatically, uh, once we've had a chance to see it firsthand just how much water there is there. Because that's still.

22:00Andrew Dunkley Yeah, it might force Elon to, uh, he's

22:03 abandoned Mars already. Too hard. Um, now that the moon's lacking water, he might go, well, we won't go there either. What's Enceladus doing at the moment?

22:15Professor Fred Watson Yes, that's right.

22:16Andrew Dunkley Yeah.

22:17Professor Fred Watson Could be squirting water out.

22:18Andrew Dunkley Yeah, well, that'd make it easy to

22:21 collect. Uh, if you want to read about that, it's on the Phys P h y s fizz.org website. Or you can read the study that was published in Frontiers in Space Technologies. You're, uh, listening to Space Nuts with Andrew Dunkley and Professor Fred Watson Watson.

22:38Generic I think we need to do a little more all

22:40 weather testing.

22:42Professor Fred Watson Amen, Space Nuts.

22:44Andrew Dunkley Our final storey. Fred Watson, uh, continues

22:46 to look for water, but on a much larger scale. Uh, we've been looking for exoplanets for yonks now and we've found five and a half thousand plus. But we haven't found a water world, an ocean world. And they think they now know how to look for them, I think is the gist of this storey.

23:08Professor Fred Watson That's correct. That's right.

23:11 Um, yeah. So, yeah, this is actually a storey I like a lot because I, um, remember being very excited, uh, back in the early 2000s, I guess, uh, when this. Exactly this same technique, uh, that is being discussed here was used to demonstrate that uh, Saturn's moon Titan has liquid ocean, not liquid oceans, I beg your pardon, liquid seas and lakes near its north pole. Uh, and it was uh, images made by the Cassini spacecraft in its early period of uh, orbiting around Saturn. The problem with Titan is it's got a thick atmosphere, uh, that is almost completely opaque. And so uh, you can use infrared to penetrate through it for a while, but uh, to some depth of clarity.

24:08 But um, the real way of exploring uh, Titan, which is what Cassini did, is by radar, uh, you do it by radar. And that's uh, one of the reasons that we've been able to map uh, these seas and lakes. But the way they were first detected was when Cassini, uh, when its cameras were aimed at Titan, Uh, uh, at a time when the angle between the spacecraft, the moon, Titan itself and the sun was such that you would get a direct reflection off the liquid surface that was thought to be near the north pole of Titan. And sure enough, uh, there was uh, what we call a glint, uh, which is a sun glint comes from a liquid water surface that was detected.

25:06 That's how Cassini, Cassini first established that there are lakes and seas, uh, uh, on Titan. And it was then they were subsequently mapped uh, very accurately by uh, Cassini's radar. I've still got some extraordinary maps that came from that era showing uh, these seas and lakes um, near Titan's north pole. So the question that is being asked in this piece of research that we're talking about once again this comes to us courtesy of Universe today, uh, is can you do the same thing with exoplanets? Supposing you have uh, a suspicion that uh, One of the 5,500 now known exoplanets, planets orbiting uh, other stars, if you have a suspicion that one of them might have conditions where liquid water could exist, or in the case

25:59 of, as in the case of Titan, liquid hydrocarbons, liquid natural gas. Um, could you use this glint technique uh, to try and establish if you did have a ah, water world, in other words a world covered completely by oceans. Uh, and those things have been hypothesised, actually we've talked about them before, these so called Hycean worlds. Uh, Hycean is basically a term that's been uh, concocted to represent a world with an atmosphere of hydrogen.

26:31 That's where the high comes from. Uh, but a liquid ocean surface, uh, hence the shen. So it's a Haitian world. How could you use this glint technique to demonstrate that a suspected Haitian world really was a Haitian world? So two scientists at the University of Arizona, uh, which is in Tucson, Uh, I've got some good friends there, but they don't include these people. I don't know them well or all I know is their names. Uh, what they've done is they've, they've done what you might call the physics of how glints might work. Uh, and the bottom line is that it's potentially a good way of doing this. But there are certain conditions that have to be fulfilled, um, because you've got to get the angles right first of

27:29 all. Um, and, and that angle is all about the object being relatively near to its parent star. So you get this um, sort of grazing angle almost of the water, sorry, the light hitting the water and then being reflected back. Now that itself presents a problem because, um, at the moment most of the exoplanets that have been discovered uh, are ah, only known because they uh, have an effect on their parent star.

28:02 Whether it's blocking the light of the parent star as they pass in front of it or whether it's pulling it slightly out of position by what we call the Doppler wobble, um, technique. Uh, these mean that you never see the planet that you're trying to observe. You just see its effect on the star. So really what we're talking about here could only apply if you've got direct observations of the planet. And if you need the planet to be close to the star to get the angle right, then that's a chance because the star is um, sometimes billions of times brighter than the planet that you're looking for. However, it's not impossible.

28:37 And there are things called coronagraphs, which are essentially uh, devices that suppress the light of a star so that you can look for planets uh, nearby. And so, uh, what um, these scientists are doing is feeding this information into people who are working on uh, something that I think is still a, ah, hypothetical spacecraft, uh, something called the Habitable Worlds Observatory, uh, which will look at the possibility of there being habitable worlds among some of these, uh, five and a half thousand known exoplanets. Uh, what they've done is they've fed uh, these conditions, this information into the designers to say, yeah, you can probably do this, but you need to do this, this, this and this when you

29:24 build your spacecraft in order for uh, potential water worlds to be discovered. So quite a nice piece of research.

29:31Andrew Dunkley Yes, indeed. I hope they do find something

29:33 like that eventually. I think it'd be really exciting to find a water world, ah, ice moons, I suppose count because, um, they have oceans inside them, but, um.

29:48Professor Fred Watson Correct.

29:49Andrew Dunkley An actual planet that is

29:52 covered in water. Um, we know of only one. But there's got to be more, surely. There's got to be more. Statistically, there's got to be more.

30:06Professor Fred Watson Yeah, one would think that's right. Whether

30:08 they are findable by our current technology is of course, another question.

30:13Andrew Dunkley Yeah, well, um, in time, maybe.

30:16 But then the Vera Rubin Observatory, who knows, um, that we'd never even thought of.

30:24Professor Fred Watson That's correct. And of course an anti Grace

30:26 Roman, uh, spacecraft recently launched, which we hope we'll see results from early next year, that does have a coronagraph. Uh, so it does have a device to look at some of these planets directly.

30:38Andrew Dunkley Yes, indeed. Uh, very exciting times ahead

30:42 and, um, won't be long before we start getting, um, some information back from, uh, that telescope either. Uh, it's on its way. Uh, yes. Uh, so if you'd like to read about that particular storey in the search for water Worlds UniverseToday, uh, dot com again is, uh, is a source that's, uh, very well worth visiting.

31:02 And that brings us to the end of the show. Fred Watson, thank you so much.

31:07Professor Fred Watson You're welcome, Andrew. Um, it's been a

31:10 pleasure and a privilege to talk to you and I. I do hope we can do it again sometime.

31:13Andrew Dunkley I, I hope we can do it really, really,

31:16 really, really soon.

31:19Professor Fred Watson Maybe so.

31:20Andrew Dunkley Catch you soon, professor, uh, Fred Watson

31:22 Watson, astronomer at large. And while you're waiting for a new episode, um, please visit our website. Uh, you can send us a message as you, um, as you like. Uh, we've had a couple of messages um, from our live audience this morning. Hello to Al in Old South Wales. He said, uh, he's just about to go to bed. And, uh, one from Halil. I hope I got that right. Who's been, uh, inspired to, um, venture, uh, out with his studies in computer engineering, uh, because he listens to Space nuts. So thanks for that message, that's lovely. Uh, but, yeah, our website, spacenutspodcast.com or spacenuts IO where you can send us messages. You can, um, do, uh, that through the AMA link and, and all sorts of other things. Uh, visit the

32:06 shop while you're there. Some new books in the shop. Yeah. Uh, and plenty of other things to do. And thanks to Huw in the studio. Couldn't, um, be with us today. Uh, we were talking about sun glints. Well, uh, Huw did a bit of a flashing of his own, so I've got to go down and bail him out after this. And from me, Andrew Dunkley thanks for your company.

32:26 We'll catch you on the next episode of Space Nuts. Bye bye, Space Nuts. You've been listening to the Space Podcast, available at Apple Podcasts, Spotify, iHeartRadio or your favourite podcast player. You can also stream on demand at bytes.

32:43Professor Fred Watson Com. This has been another quality podcast

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32:48Generic Com. Um.