Latest / Space Nuts: Astronomy Insights & Cosmic Discoveries / Asteroid Spin, Superpuff Mysteries & Martian Groundwater Revelations

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Asteroid Spin, Superpuff Mysteries & Martian Groundwater Revelations · Space Nuts: Astronomy Insights & Cosmic Discoveries

• 0:00
  Speaker 1: Hello again and thanks for joining us on another episode
• 0:02
  Speaker 1: of Space Nuts where we talk astronomy and space science.
• 0:06
  Speaker 1: My name is Andrew Uncley. Thanks for your company. If
• 0:08
  Speaker 1: you're joining us for the very first time, welcome to
• 0:10
  Speaker 1: our little astronomical community. Coming up on today's program, we're
• 0:15
  Speaker 1: going to look at one spun out asteroid and a
• 0:19
  Speaker 1: super puff planet as well. The story that excites me
• 0:23
  Speaker 1: most is what they've discovered about Martian groundwater and what
• 0:27
  Speaker 1: it means for the history of Mars. That's all coming
• 0:30
  Speaker 1: up on this episode of Space Nuts. Fifteen second in
• 0:35
  Speaker 1: Channal ten nine Ignition Big on Space Nuts NY four
• 0:42
  Speaker 1: three two one Space Nuts as an act re bought it.
• 0:48
  Speaker 1: Bill's good and it is time to say hello to
• 0:52
  Speaker 1: Fred Wat's an astronomer at large joining us as always.
• 0:55
  Speaker 2: Hi Fred, Hello Andrew, very good to see you, and
• 0:59
  Speaker 2: hear you good to.
• 1:00
  Speaker 1: See he used to Yes, yes all as well. I
• 1:05
  Speaker 1: take it.
• 1:06
  Speaker 2: Yeah. I was just going to mention we heard a
• 1:09
  Speaker 2: couple of days ago that Winton in Queensland has become
• 1:16
  Speaker 2: Queensland's first international Dark Sky community. It's Dark Sky International
• 1:22
  Speaker 2: is the global body that dishes out these things, but
• 1:27
  Speaker 2: this little outback town one thousand people. They've put together
• 1:31
  Speaker 2: the application and got themselves awarded the first international dark
• 1:35
  Speaker 2: sky community in Queensland. So it's you know, in fact,
• 1:41
  Speaker 2: they join the Jump Up Dark Sky Sanctuary at the
• 1:45
  Speaker 2: Australian Age of Dinosaurs to become Australia's eighth dark sky place.
• 1:50
  Speaker 2: And I'm reading from my wife Marnie's LinkedIn post about
• 1:55
  Speaker 2: that because I think she probably had something to do
• 1:56
  Speaker 2: with it.
• 1:57
  Speaker 1: Probably. Of course, it's a bit easy for Winton to
• 2:01
  Speaker 1: be a dark sky community because they only have to
• 2:03
  Speaker 1: turn one light off and truck.
• 2:06
  Speaker 2: It's almost like that dark sky communities are interesting there,
• 2:10
  Speaker 2: you know. I mean we have here in Sydney, the
• 2:15
  Speaker 2: Southern Hemisphere's first urban dark sky park, which is actually
• 2:19
  Speaker 2: a suburb of Sydney. It's one of the most remote
• 2:21
  Speaker 2: suburbs of Sydney, but you can imagine anything anywhere near
• 2:25
  Speaker 2: Sydney is not particularly dark, but this place is reasonably
• 2:30
  Speaker 2: dark and the main thing that qualifies them to have
• 2:34
  Speaker 2: this status is that there is a willingness to preserve
• 2:39
  Speaker 2: the night sky, so the lighting and you know, the
• 2:42
  Speaker 2: policies that are in place. It's in Sydney's Northern Beaches,
• 2:45
  Speaker 2: not very far from where we are now, and all
• 2:47
  Speaker 2: those policies contribute towards the qualification for an urban dark
• 2:51
  Speaker 2: sky park.
• 2:52
  Speaker 1: That's pretty cool. Yeah, yeah, I know Dubbo Regional Council
• 2:59
  Speaker 1: where I live, has done as much as it can
• 3:03
  Speaker 1: do well, probably could do more. But you know they've
• 3:07
  Speaker 1: taken into account that the tell us go up the
• 3:10
  Speaker 1: road at Guna Barabra and it's not far away, and
• 3:13
  Speaker 1: that we are a factor in the in.
• 3:16
  Speaker 2: The light pollution problem.
• 3:18
  Speaker 1: So we have different lighting in this city to curtail
• 3:23
  Speaker 1: the effect. So all the lights point downwards. They're not
• 3:26
  Speaker 1: bright white lights there, they're more of an amber glow.
• 3:31
  Speaker 2: It was great. Yeah. In fact, they're actually moundated to
• 3:34
  Speaker 2: do that by the by the Dutch sky regulations that
• 3:38
  Speaker 2: applies because you're within one hundred kilometers at least part
• 3:41
  Speaker 2: of double ways. But regional Council, I think, is sorry
• 3:48
  Speaker 2: and it's it's it's in the Western Plains Regional Council.
• 3:51
  Speaker 2: Is that right?
• 3:53
  Speaker 1: Midwestern regional councils the other.
• 3:55
  Speaker 2: One, yes, yeah, so that they are include did within
• 4:00
  Speaker 2: the one hundred kilometer radius region, but actually for state
• 4:05
  Speaker 2: significant infrastructure goes out to two hundred kilometers, so then
• 4:08
  Speaker 2: everyone places further afield that would yes, have to have
• 4:11
  Speaker 2: dark skies.
• 4:12
  Speaker 1: Interesting anyway, because a lot of people wouldn't really understand
• 4:16
  Speaker 1: or even know about the the requirements of dark sky policy,
• 4:22
  Speaker 1: would they?
• 4:23
  Speaker 2: No, they wouldn't They wonder way the lights of different
• 4:26
  Speaker 2: color from everybody else.
• 4:27
  Speaker 1: Yes, in Dubbo who listen to this, and I know
• 4:30
  Speaker 1: there are a few. We'll probably have a good look
• 4:33
  Speaker 1: at the street lights next next time they're out at night,
• 4:35
  Speaker 1: because they are different. They are different. Let's get down
• 4:39
  Speaker 1: to business. We've got quite a bit to talk about,
• 4:42
  Speaker 1: and this first story is about one spun out asteroid.
• 4:46
  Speaker 1: We've been talking about a lot of rocks in recent episodes, asteroids, comets,
• 4:51
  Speaker 1: et cetera. But this one caught the attention of astronomers
• 4:56
  Speaker 1: last year and they've just published a paper about it.
• 5:00
  Speaker 2: Yeah. In fact, it's sort of hard on the heels
• 5:03
  Speaker 2: of one of the stories we covered last week of
• 5:07
  Speaker 2: the episode before last, which was about the possible transfer
• 5:12
  Speaker 2: of material between asteroid Didimos and its moon dimorphous the
• 5:16
  Speaker 2: ones that were visited by the Dart spacecraft, and it
• 5:20
  Speaker 2: was thought that the spin of that asteroid Didimos had
• 5:23
  Speaker 2: released material that might have found its way onto dimorphous
• 5:28
  Speaker 2: But this is a different story, and its research that
• 5:31
  Speaker 2: has come not from a spacecraft but from a telescope
• 5:35
  Speaker 2: that you and I are going to talk a lot
• 5:37
  Speaker 2: about in the next few years at the Vera sa
• 5:41
  Speaker 2: Rumen Observatory in Chile, the eight point four meter wide
• 5:44
  Speaker 2: angled telescope that is going to find all these really
• 5:48
  Speaker 2: interesting time related objects in the universe and time related
• 5:53
  Speaker 2: phenomena what we call transient events. And I think it
• 5:58
  Speaker 2: was last year, Yes, you're right, it was last year
• 6:01
  Speaker 2: that the ver C Reuben Observatory court an asteroid which
• 6:09
  Speaker 2: rejoices in the name of twenty twenty five N forty five.
• 6:13
  Speaker 2: That's a typical asteroid name as bestowed by the International
• 6:16
  Speaker 2: Astronomical Union, while it's still a provisional designation. It's about
• 6:21
  Speaker 2: seven hundred and ten meters wide, but is a complete
• 6:27
  Speaker 2: basket case in terms of the speed with which it rotates,
• 6:32
  Speaker 2: because whilst an object that size would normally be rotating
• 6:37
  Speaker 2: at a rate measured you know, in hours, maybe once
• 6:40
  Speaker 2: every two or three hours or something like that, this
• 6:43
  Speaker 2: one is rotating in one minute fifty four seconds. Yeah,
• 6:50
  Speaker 2: it's unbelievable. So the main question is how does it
• 6:55
  Speaker 2: hold together, because you know that rotation produces an acceleration
• 7:01
  Speaker 2: at the surface that you would think certainly if it
• 7:03
  Speaker 2: was a Rubbel pilot it would have fallen into bits
• 7:05
  Speaker 2: a long time ago. So that tells us it's not.
• 7:10
  Speaker 2: It doesn't really tell us much more though, except perhaps
• 7:14
  Speaker 2: it may be a metal asteroid. We've got a metal
• 7:17
  Speaker 2: asteroid on our horizons at the moment, with a Psyche
• 7:19
  Speaker 2: spacecraft on its way to the asteroid. Psyche, which is
• 7:23
  Speaker 2: a probably not solid metal but has a very high,
• 7:31
  Speaker 2: very high proportion of metal in its makeup. Maybe this
• 7:35
  Speaker 2: is something like that twenty twenty five, I me in
• 7:39
  Speaker 2: forty five, might be, you know, the second predominantly metal
• 7:45
  Speaker 2: asteroid to be discovered. We don't know, but it certainly
• 7:49
  Speaker 2: is a matter of interest. It may be that it's
• 7:51
  Speaker 2: got an odd internal structure as well, you know, the
• 7:59
  Speaker 2: the might for example, I mean, just think of this one, Andrew.
• 8:04
  Speaker 2: What if it's hollow, something like that, something really weird.
• 8:09
  Speaker 1: Who knows, Yeah, that would be strange, although I would
• 8:14
  Speaker 1: expect that at that kind of spin rate, being a
• 8:16
  Speaker 1: hollow wouldn't help. It wouldn't help at all. Its integrity
• 8:22
  Speaker 1: might be compromised. I just did a little bit of
• 8:26
  Speaker 1: a thought experiment, and I looked up what would happen
• 8:30
  Speaker 1: to Earth if it's spun at the same rate as
• 8:34
  Speaker 1: that asteroid. Now it's spinning seven hundred and fifty eight
• 8:38
  Speaker 1: times faster than earthy. If Earth was spinning at that
• 8:43
  Speaker 1: kind of speed one point and nine minutes per rotation,
• 8:48
  Speaker 1: it would it would be a disaster. It would destroy
• 8:52
  Speaker 1: the crust. There'd be total liquidization, we'd lose our atmosphere,
• 8:56
  Speaker 1: the wind speeds would be insane, and around the equation
• 9:00
  Speaker 1: that there would be reverse rain due to the center
• 9:02
  Speaker 1: feeble force.
• 9:04
  Speaker 2: So I'm going up.
• 9:06
  Speaker 1: Now, that's a seven hundred and fifty eight times faster
• 9:09
  Speaker 1: But even if we were spinning fifty to one hundred
• 9:11
  Speaker 1: times faster, it would still cause catastrophic flooding, and the
• 9:17
  Speaker 1: oceans would migrate towards the equator and most of the
• 9:22
  Speaker 1: land to be covered. It would be a mess.
• 9:24
  Speaker 2: It won't be a mess. We think the fastest the
• 9:27
  Speaker 2: Earth has rotated in its infancy is about once in
• 9:31
  Speaker 2: four hours. That's thought to be how fast it was
• 9:36
  Speaker 2: rotating when it formed, But it of course slowed down
• 9:41
  Speaker 2: with the transfer of energy to the Moon and things
• 9:43
  Speaker 2: of that sort. Yeah, but yeah, I think once in
• 9:45
  Speaker 2: four hours was the is what's thought to be the
• 9:48
  Speaker 2: fastest just pulling that from so.
• 9:50
  Speaker 1: That'd year six times faster than it is it.
• 9:52
  Speaker 2: Yeah.
• 9:53
  Speaker 1: Yeah, and even at that rate it would be uninhabitable.
• 9:57
  Speaker 1: I just did a quick check. Okay, I'm sure it
• 10:01
  Speaker 1: was suffering catastrophic geological and atmospheric changes, so that's right.
• 10:06
  Speaker 2: I mean it was still I think it was still
• 10:08
  Speaker 2: pretty Milton at that time, so it was. It was.
• 10:11
  Speaker 1: It was going through its cooling phase.
• 10:14
  Speaker 2: Not a nice place to be, No, it wouldn't it been.
• 10:16
  Speaker 1: No, But if you'd like to read about this spun
• 10:19
  Speaker 1: out asteroid as observed through the Virus Ruben Observatory in Chile,
• 10:24
  Speaker 1: you can read all about it on the Daily Galaxy
• 10:28
  Speaker 1: dot com website or the Astrophysical Journal Letters, where the
• 10:32
  Speaker 1: paper has been published. This is Space Nuts with Andrew
• 10:36
  Speaker 1: Dunkley and Professor Fred Watson. Let's take a little break
• 10:41
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• 12:32
  Speaker 2: Nuts, Ween Anguality.
• 12:35
  Speaker 1: They've here the plant space nuts. Now we've heard about
• 12:41
  Speaker 1: superpuff planets before. Fred, there's another one in the news.
• 12:47
  Speaker 1: I think this one's Kepler fifty one D. They're finding
• 12:49
  Speaker 1: a lot of planets out there, it's really weird ones,
• 12:53
  Speaker 1: and this is in the weird category. It is.
• 12:57
  Speaker 2: Yes, it's a strange object. As you said, it's one
• 13:01
  Speaker 2: of the exo planets discovered by the Kepler space Mission,
• 13:06
  Speaker 2: which was very very productive observing planets going around other
• 13:10
  Speaker 2: stars by the dip in the star's light as the
• 13:13
  Speaker 2: planet passed in front of it. So Kepler fifty one
• 13:17
  Speaker 2: D has been studded with the James Web Space Telescope
• 13:23
  Speaker 2: in order to try and identify the elements in its
• 13:29
  Speaker 2: atmosphere or the chemicals in its atmosphere, which you can
• 13:32
  Speaker 2: do when a planet with an atmosphere passes in front
• 13:36
  Speaker 2: of its parent star, which is what's happening with Kepler
• 13:39
  Speaker 2: fifty one D. Some of the light from the star
• 13:43
  Speaker 2: filters through the atmosphere, and the atmosphere puts on it
• 13:45
  Speaker 2: puts its kind of spectroscopic fingerprint on the light, so
• 13:49
  Speaker 2: that when we use a spectrograph with a sort of
• 13:52
  Speaker 2: prism or similar mechanism for dispersing the light, then you
• 13:58
  Speaker 2: can see the the chemical signature of what's in the
• 14:03
  Speaker 2: atmosphere because it's it's faint imprint is there. So they
• 14:09
  Speaker 2: did that, and what did they find? Nothing? Not not
• 14:14
  Speaker 2: not that there's no atmosphere, because they know this object,
• 14:17
  Speaker 2: as you've said, it's it's a super puff, which means
• 14:21
  Speaker 2: it's an object. It's roughly the size of Saturn, so
• 14:27
  Speaker 2: that's what nine times the Earth diameter there about something
• 14:30
  Speaker 2: like that. But its mass is not that much bigger
• 14:33
  Speaker 2: than Earth. It's a few times the Earth. So it's
• 14:35
  Speaker 2: got a very low density. That's the that's the bottom line.
• 14:40
  Speaker 2: You've got something with a big diameter and a small
• 14:43
  Speaker 2: mass hence low density and well as the as the
• 14:50
  Speaker 2: one of the articles that reports this comments, planetary scientists
• 14:55
  Speaker 2: sometimes compare such planets to cotton candy, which I think
• 15:00
  Speaker 2: we call well, we used to call it candy floss.
• 15:04
  Speaker 2: We call it loss airy floss. That's try loss that stuff.
• 15:08
  Speaker 1: It's good when fairies do floss. It's very important for
• 15:12
  Speaker 1: their dental health, saying they are two fairies most of them.
• 15:16
  Speaker 2: Oh, I love it, I love it there, Yes, they
• 15:20
  Speaker 2: would have to be too fairies. That's right.
• 15:23
  Speaker 1: Ye us feels very floss is not good for dental health.
• 15:29
  Speaker 2: My only recollection of that stuff is ends up all
• 15:31
  Speaker 2: over your face, and that's.
• 15:33
  Speaker 1: Under straight anyway. Especially we'd like give it to young children.
• 15:36
  Speaker 2: Yes, or old men. Yeah, that's right though. It's it's
• 15:43
  Speaker 2: it's it's something that it has a structure that is
• 15:46
  Speaker 2: very different from our own planet. So what did they do?
• 15:50
  Speaker 2: They said, Oh, we're going to find out what's going
• 15:52
  Speaker 2: on here, observe the star as the planet passes in
• 15:56
  Speaker 2: front of it. Look for the spectrum imprint on the
• 15:59
  Speaker 2: light coming through the planet's atmosphere. And what did they see? Nothing?
• 16:05
  Speaker 2: And so the interpretation of that is that the atmosphere
• 16:11
  Speaker 2: very high. In the atmosphere, you've got haze. So Hayes
• 16:18
  Speaker 2: is basically particulate matter. It's and it's suspended in the atmosphere,
• 16:26
  Speaker 2: and it's so dense as to block the light coming
• 16:32
  Speaker 2: through it, so you don't see the imprint of what
• 16:34
  Speaker 2: the gases in the atmosphere are. So an aerosol of
• 16:40
  Speaker 2: haze is basically you know, it's basically what's blocking the
• 16:47
  Speaker 2: light and what's giving These scientists, by the way, from
• 16:50
  Speaker 2: Penn State University, they've sort of observed enough of the
• 16:56
  Speaker 2: light to deduce that there is a thick haze layer there,
• 17:00
  Speaker 2: but there's no no sign of As I said, it's
• 17:05
  Speaker 2: blocking all the all the evidence of what chemicals you have.
• 17:09
  Speaker 2: So the big problem now is working out how that
• 17:12
  Speaker 2: haze got there. And and you know what, what actually
• 17:17
  Speaker 2: supports it? Why is why is this planet so hazy?
• 17:21
  Speaker 2: And that is I think where the where the situation lies.
• 17:28
  Speaker 2: Now that you've got this world, which is fairly cool
• 17:36
  Speaker 2: in the sense that it's it's hotter than our planets
• 17:39
  Speaker 2: is it's way way within the goal, you know, beyond
• 17:42
  Speaker 2: the Goldilock zone. But it's all about the chemistry that
• 17:46
  Speaker 2: would at the temperatures that we believe the atmosphere of
• 17:49
  Speaker 2: this planet is out the chemistry that would produce that haze,
• 17:53
  Speaker 2: and that I think is an ongoing piece of work.
• 17:56
  Speaker 1: Yeah, just reading through the information, it seems to be
• 18:02
  Speaker 1: related to temperature. Yes, maybe the cause of this. I'm
• 18:10
  Speaker 1: guessing it's technically cooler than our own gas giants. Would
• 18:14
  Speaker 1: that be fair to say.
• 18:17
  Speaker 2: Our gas giants at their surface are well below those temperatures? Oh?
• 18:23
  Speaker 1: Okay, surface.
• 18:24
  Speaker 2: So the top layer of Saturn is, if I remember rightly,
• 18:28
  Speaker 2: about minus ninety five or thereabouts, right, or is it
• 18:33
  Speaker 2: minus one hundred and ninety five? I think it is.
• 18:35
  Speaker 2: You got nearest to minus one hundred and ninety five. Sorry,
• 18:38
  Speaker 2: I'm pulling numbers from all reports there. So this one's
• 18:43
  Speaker 2: much hotter, yes, that's right. Yeah. But the the other
• 18:50
  Speaker 2: interesting thing about this system, the Kepler fifty one star
• 18:55
  Speaker 2: has I think it's got something like four might even
• 18:59
  Speaker 2: be five knowns, and three of them are these super puffs,
• 19:04
  Speaker 2: very low density objects. So there's something going on in
• 19:07
  Speaker 2: that solar system that really doesn't match what goes on
• 19:09
  Speaker 2: in ours. Yeah.
• 19:11
  Speaker 1: I wonder if it's got anything to do with the
• 19:13
  Speaker 1: star itself activating this situation, I don't know, or maybe
• 19:19
  Speaker 1: they're affecting each other.
• 19:22
  Speaker 2: Yeah, it is. It is a sun like star, but
• 19:25
  Speaker 2: it's at a much more youthful stage in its history
• 19:28
  Speaker 2: than our sun is.
• 19:29
  Speaker 1: Well, that's why it likes cotton candy could be. I
• 19:34
  Speaker 1: imagine Fred, that there are astronomers on one of the
• 19:37
  Speaker 1: rocky planets in the Kepitlert system looking at our solar system, going,
• 19:41
  Speaker 1: they've got planets that look like boiled lollies. How is
• 19:46
  Speaker 1: that possible? Because that's because that's Jupiter and Sat and
• 19:51
  Speaker 1: do have that appearance. Or they might be going, what
• 19:54
  Speaker 1: they've got rings around their planets? How is that possible?
• 19:57
  Speaker 2: Yeah, things like that. Who knows.
• 20:00
  Speaker 1: We're used to what we've got and when we see
• 20:03
  Speaker 1: something that just doesn't fit our definition of a solar system, yeah, well,
• 20:10
  Speaker 1: they write papers about it like this because it's hard.
• 20:13
  Speaker 1: It's hard to understand what's going on.
• 20:17
  Speaker 2: Exactly, but it's telling us stuff that we didn't know before,
• 20:21
  Speaker 2: which is interesting. Yep, it is.
• 20:23
  Speaker 1: It is very interesting. If you'd like to read all
• 20:25
  Speaker 1: about it, it's on the Brighter Side dot news website,
• 20:29
  Speaker 1: and I'm sure they've published a paper somewhere, Yes, in
• 20:32
  Speaker 1: the Astronomical Journal, of course. This is space Nuts. Andrew
• 20:36
  Speaker 1: Dunkley here with Professor Fred Watson.
• 20:41
  Speaker 2: We choose to go to the moon and this decay
• 20:43
  Speaker 2: and do the other thing, not because they are easy,
• 20:47
  Speaker 2: but because they are hard.
• 20:48
  Speaker 1: These nuts here we do it hard. Here. It's space nuts,
• 20:52
  Speaker 1: no doubt about it. Fred. Let's go to Mars because
• 20:59
  Speaker 1: in recent times you and I have spoken about some
• 21:01
  Speaker 1: of the things they're discovering about Mars and what it
• 21:06
  Speaker 1: will mean for people who will ultimately spend lengthy periods
• 21:11
  Speaker 1: on or in the planet, depending on whether or not
• 21:15
  Speaker 1: they can find somewhere to put themselves. And there seem
• 21:18
  Speaker 1: to be places popping up. This story, however, is all
• 21:23
  Speaker 1: about ground water and what it means for Mars' history
• 21:29
  Speaker 1: as a wet planet. This is really really interesting stuff.
• 21:33
  Speaker 2: It is, Yes, I mean, I guess we're used to
• 21:39
  Speaker 2: the idea that probably mars Is northern hemisphere had at
• 21:42
  Speaker 2: least seas on it, and probably an ocean. We've talked
• 21:46
  Speaker 2: about several pieces of research recently that seemed to suggest
• 21:50
  Speaker 2: that it was actually a large body of water that
• 21:52
  Speaker 2: lasted for a long time covering males Is northern hemisphere.
• 21:57
  Speaker 2: But what we haven't sort of studied is the you know,
• 22:01
  Speaker 2: the more detailed hydrology of Mars, the way the water
• 22:06
  Speaker 2: behaves in Mars But this is a paper that's come
• 22:09
  Speaker 2: from Attract University and it's about an analysis of creators
• 22:17
  Speaker 2: in the Northern Hemisphere, so that region where there was
• 22:22
  Speaker 2: an ocean at one time. These are crators which are
• 22:26
  Speaker 2: quite deep. They are about four kilometers deep, so yeah,
• 22:32
  Speaker 2: they're big. You know, that's that's significant. I think the
• 22:35
  Speaker 2: cross of Mars is only something like twenty or thirty
• 22:39
  Speaker 2: kilometers if I remember rightly, like ours which is fifty
• 22:42
  Speaker 2: two hundred kilometers, but anyway, four kilometers below the sort
• 22:48
  Speaker 2: of Martian datum, which on Earth we'd call mean sea level,
• 22:51
  Speaker 2: but they don't have sea of Mars, so it's a
• 22:54
  Speaker 2: sort of standard datum. And what what the analysis has
• 22:59
  Speaker 2: shown is that there are features in the walls and
• 23:09
  Speaker 2: base of the basis of these craters which indicate presence
• 23:16
  Speaker 2: of water over a long period. And you know that
• 23:22
  Speaker 2: we've just talked about the ocean. I think we're talking
• 23:25
  Speaker 2: here about a time when the ocean wasn't there, because
• 23:29
  Speaker 2: these are craters in the Northern Hemisphere. But in these
• 23:34
  Speaker 2: deep craters show water formed erosion and water formed features
• 23:40
  Speaker 2: in the bottom. But the smoking gun here is that
• 23:45
  Speaker 2: for these twenty four craters, most of them. Most of
• 23:51
  Speaker 2: these water formed features occur at the same depth. Basically,
• 23:56
  Speaker 2: So what this seems to be suggesting is a water
• 24:01
  Speaker 2: table a bit like we have here on Earth. We've
• 24:04
  Speaker 2: got groundwater that produces a water table, and that's suggesting
• 24:09
  Speaker 2: that maybe at that depth there was a water table
• 24:13
  Speaker 2: that was across multiple sizes, and so that suggests that
• 24:18
  Speaker 2: this perhaps supports the existence of a widespread groundwater system
• 24:24
  Speaker 2: rather than just individual pockets of water. The fact that
• 24:27
  Speaker 2: they're all at the same depth. Yeah, there's a quote
• 24:30
  Speaker 2: from that's the telling sign, isn't it It is? Yeah.
• 24:35
  Speaker 2: Dr Salazi is the lead author, and a quote is
• 24:40
  Speaker 2: we trace this water in our study, as its scale
• 24:42
  Speaker 2: and role is a matter of debate, and we found
• 24:45
  Speaker 2: the first geological evidence of a planet wide groundwater system
• 24:49
  Speaker 2: on Mars, and so you know, that's also the idea
• 24:55
  Speaker 2: that this is the whole planet is I think quite
• 24:59
  Speaker 2: a step forward. That we've got a hydrological network kind
• 25:05
  Speaker 2: of comparable with the Earth. It would go back to
• 25:10
  Speaker 2: a time when the you know, when Mars was more
• 25:15
  Speaker 2: geological active than it is now. And I think I
• 25:18
  Speaker 2: think the model that they're suggesting, I think I've got
• 25:20
  Speaker 2: this right is that as the surface water diminished, as
• 25:24
  Speaker 2: this ocean dried up, it basically migrated downwards and basically
• 25:31
  Speaker 2: formed a long term stable water table, as it said,
• 25:35
  Speaker 2: four kilometers beneath the surface. We know that there is
• 25:39
  Speaker 2: still water under the surface in regions. I mean thinking
• 25:42
  Speaker 2: of the Phoenix mission that scraped the surface of the
• 25:48
  Speaker 2: Northern Arctic in Mars with its back home, and they
• 25:51
  Speaker 2: only had to move a few millimeters of soil before
• 25:54
  Speaker 2: they were on solid ice, which is basically you know,
• 25:57
  Speaker 2: sub surface ice. So in some respect perhaps that groundwater
• 26:03
  Speaker 2: table still exists in the form of ice. Really interesting
• 26:07
  Speaker 2: piece of work there, with some very interesting topological features
• 26:11
  Speaker 2: in the paper that they've written, and you can see
• 26:14
  Speaker 2: the evidence for these water water formed features.
• 26:18
  Speaker 1: Of course, fraid I'm sitting on groundwater as I speak,
• 26:23
  Speaker 1: not literally, but it's below my feet, below my house
• 26:27
  Speaker 1: all through this region, the Great Artisian Basin. In fact,
• 26:32
  Speaker 1: it's so big and so well used, we'll say that
• 26:36
  Speaker 1: there's a department that is in charge of looking after
• 26:41
  Speaker 1: it in this country. And it stretches from Queensland right
• 26:44
  Speaker 1: down through New South Wales and into Victoria and South Australia.
• 26:49
  Speaker 1: I think it's massive.
• 26:51
  Speaker 2: Is it? Something like a fifth of the area of
• 26:54
  Speaker 2: Australia is he empired by the Great Artisian Basin. I've
• 26:57
  Speaker 2: got a map somewhere that I've online one day and
• 27:01
  Speaker 2: I was staggered by just how big it is.
• 27:03
  Speaker 1: So I've seen pictures of the basin as well, and
• 27:07
  Speaker 1: to give people an idea of how significant it is.
• 27:10
  Speaker 1: So where I live, we have a river running through,
• 27:14
  Speaker 1: but we also suffer some significant droughts at times, but
• 27:19
  Speaker 1: we draw on the groundwater to supplement our water supply.
• 27:24
  Speaker 1: We can never run out of water here unless the
• 27:28
  Speaker 1: Great Artesian Basin actually runs out of water. And that's
• 27:31
  Speaker 1: one of the fears that it's been overused for so long,
• 27:36
  Speaker 1: going back one hundred years or more, they used to
• 27:40
  Speaker 1: drill down, tap the water and just let it run
• 27:43
  Speaker 1: on the surface because it came up under natural pressure
• 27:47
  Speaker 1: at a temperature of fifty degrees I think something around
• 27:50
  Speaker 1: that mark. But it's a natural resource that's been use
• 27:56
  Speaker 1: very very heavily in agriculture and domestic supply out here
• 28:00
  Speaker 1: for over one hundred years, probably near two hundred years
• 28:03
  Speaker 1: in some respects. And now they're trying to figure out
• 28:06
  Speaker 1: whether or not we've overdone it and then try to
• 28:11
  Speaker 1: cap a lot of these old bores that have just
• 28:14
  Speaker 1: been running water, running water for decades without stopping.
• 28:20
  Speaker 2: Do you know how deep it is? One hundred banilla
• 28:23
  Speaker 2: beneath the surface. I'm just thinking. So when I lived
• 28:26
  Speaker 2: in Koonerburben, I lived on a property and we had
• 28:29
  Speaker 2: a board there and the water was I think ninety
• 28:32
  Speaker 2: feet if I remember rightly, that's where we hit the water. Yeah,
• 28:36
  Speaker 2: well the property whatever that is in meters.
• 28:39
  Speaker 1: Okay, So it's the world's largest and deepest tesian basin.
• 28:44
  Speaker 1: It's got a depth of three thousand meters in some
• 28:47
  Speaker 1: parts that would be its deepest point. But generally you
• 28:53
  Speaker 1: can drill. You've got to drill down to about two
• 28:55
  Speaker 1: thousand meters to tap the water, although in some places
• 28:59
  Speaker 1: itally pushes up through the surface. Even just out of
• 29:02
  Speaker 1: town from here, there are little pockets of water that
• 29:07
  Speaker 1: are naturally at the surface, that are that are hot
• 29:11
  Speaker 1: spring water. And even up you move further north, you've
• 29:15
  Speaker 1: got those famous bore bars in places like Maure and
• 29:19
  Speaker 1: Lightning religin Pilarger. Yeah, so it does come to the
• 29:24
  Speaker 1: surface naturally, but yeah, to actually tap it under pressure
• 29:29
  Speaker 1: and get it to the surface. You've got to go
• 29:31
  Speaker 1: down pretty deep by the look of it. It's fascinating, though,
• 29:35
  Speaker 1: isn't it. And it shouldn't surprise us that Mars probably
• 29:39
  Speaker 1: had a groundwater in its past, but it sounds like
• 29:43
  Speaker 1: it was post ocean time.
• 29:45
  Speaker 2: It does from what we're really think here.
• 29:48
  Speaker 1: So does that suggest that the water migrated underground as
• 29:53
  Speaker 1: the planet changed?
• 29:55
  Speaker 2: Yes, I think that's the bottom line. I think that's
• 29:56
  Speaker 2: what these authors are suggesting, that it receded downwards.
• 30:01
  Speaker 1: We just keep learning so much more about Mars, and
• 30:04
  Speaker 1: I can't stop being fascinated by the place. It's incredible.
• 30:10
  Speaker 1: You can read about that at the Daily Galaxy dot
• 30:12
  Speaker 1: com website, or you can go to the paper at
• 30:16
  Speaker 1: the Journal of Geophysical Research Planets. That's it, Fred, We
• 30:22
  Speaker 1: are done and dusted.
• 30:25
  Speaker 2: Very quickly today.
• 30:27
  Speaker 1: Yeah, it's I've got the same philosophy we've golf. A
• 30:30
  Speaker 1: quick game is a good game. Unfortunately it never works
• 30:35
  Speaker 1: out that way because I hit it too many times.
• 30:37
  Speaker 1: But thank you, Fred, and we look forward to your
• 30:40
  Speaker 1: company on the next episode.
• 30:41
  Speaker 2: I look forward to yours too, Andrew.
• 30:43
  Speaker 1: Thank you. Professor Fred Wat's an astronomer at large talking
• 30:47
  Speaker 1: astronomy and Space Science every week. Don't forget to visit
• 30:50
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• 30:53
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• 30:56
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• 30:59
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• 31:04
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• 31:06
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• 31:09
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• 31:12
  Speaker 1: appreciate it. And thanks to Hu in the studio, you're
• 31:15
  Speaker 1: going to love his excuse today. He heard about Martian
• 31:19
  Speaker 1: ground water and thought that you could grind water, so
• 31:23
  Speaker 1: he's been trying that it's not working and he's not
• 31:27
  Speaker 1: giving up anyway. That's today's excuse. And to me Andrew Duntrey,
• 31:31
  Speaker 1: thanks for your company. We'll see you on the next
• 31:33
  Speaker 1: episode of Space Nuts. Bye Bye Snuts. You'll be listening
• 31:38
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