In this fascinating episode of Space Nuts, host Andrew Dunkley and the ever-knowledgeable Professor Fred Watson explore the latest revelations about the Moon's interior, the complexities of Hubble tension, and an exciting discovery in the Kuiper Belt. Buckle up for a cosmic ride through these intriguing topics!
Episode Highlights:
- The Moon's Interior Unveiled: Andrew and Fred Watson discuss the findings from the Grail mission, revealing surprising differences in the Moon's mantle and how temperature variations may explain the stark contrasts between the near and far sides of our lunar companion.
- Understanding Hubble Tension: The duo dives into a new theory surrounding Hubble tension, exploring the evolving nature of dark matter and dark energy, and how recent data might reshape our understanding of the universe's expansion.
- A Triple System in the Kuiper Belt: They discuss the discovery of a potential triple system involving the asteroid 148780 Algeria, made using the Hubble Space Telescope, highlighting the rarity of such systems and their significance in understanding the solar system's formation.
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Stay curious, keep looking up, and join us next time for more stellar insights and cosmic wonders. Until then, clear skies and happy stargazing.
(00:00) Welcome to Space Nuts with Andrew Dunkley and Fred Watson Watson
(01:20) Discussion on the Moon's interior and the Grail mission findings
(15:00) Exploring the latest theories on Hubble tension
(25:30) Discovery of a triple system in the Kuiper Belt
For commercial-free versions of Space Nuts, join us on Patreon, Supercast, Apple Podcasts, or become a supporter here: https://www.spreaker.com/podcast/space-nuts-astronomy-insights-cosmic-discoveries--2631155/support.
00:00:00 --> 00:00:00 Professor Fred Watson: Hello again.
00:00:00 --> 00:00:03 Andrew Dunkley: Andrew Dunkley here from Space Nuts, where
00:00:03 --> 00:00:05 we talk astronomy and space science. Good to
00:00:05 --> 00:00:07 have your company. Coming up on this episode,
00:00:08 --> 00:00:10 we are, going to talk about the moon. It's
00:00:10 --> 00:00:12 got a near side, it's got a far side, but
00:00:12 --> 00:00:15 we're going to talk about the inside. it's,
00:00:15 --> 00:00:17 discovery of the Grail mission.
00:00:18 --> 00:00:20 which means what we're talking about is a
00:00:20 --> 00:00:23 flesh wound. another Hubble tension. Think
00:00:23 --> 00:00:26 about it. Another Hubble tension theory. And
00:00:26 --> 00:00:28 we're talking evolution this time. And a
00:00:28 --> 00:00:31 triple system in the Kuiper Belt. Belt. So
00:00:31 --> 00:00:34 buckle up for this episode of space
00:00:34 --> 00:00:34 nuts.
00:00:34 --> 00:00:37 Voice Over Guy: 15 seconds. Guidance is internal.
00:00:37 --> 00:00:40 10, 9. Ignition
00:00:40 --> 00:00:43 sequence start. Space nuts. 5, 4, 3,
00:00:43 --> 00:00:46 2. 1. 2, 3, 4, 5, 5, 4,
00:00:46 --> 00:00:49 3, 2, 1. Space nuts. Astronauts
00:00:49 --> 00:00:52 report it feels good. And back with us
00:00:52 --> 00:00:54 again is Professor Fred Watson Watson,
00:00:54 --> 00:00:56 astronomer at large. Hello, Fred.
00:00:56 --> 00:00:58 Professor Fred Watson: Hello, Andrew. Hello. Took me in couple.
00:00:58 --> 00:01:00 Couple of seconds. But I did get the.
00:01:00 --> 00:01:02 Andrew Dunkley: To get the, flesh. The flesh wound. Flesh
00:01:02 --> 00:01:04 wound. The Grail mission.
00:01:04 --> 00:01:05 Professor Fred Watson: Only a flesh wound.
00:01:05 --> 00:01:06 Andrew Dunkley: It's only a flesh wound.
00:01:06 --> 00:01:09 Professor Fred Watson: That's right. no arms, no legs, but
00:01:09 --> 00:01:10 nothing.
00:01:11 --> 00:01:14 Andrew Dunkley: Flesh wound. so, yes, that I,
00:01:14 --> 00:01:17 I can't help dad jokes and, and, and
00:01:18 --> 00:01:21 I, I. When I do the presentations at golf on
00:01:21 --> 00:01:24 Fridays, which has become my job somehow.
00:01:24 --> 00:01:26 I always have to finish on a dad joke. It's
00:01:26 --> 00:01:27 just become a thing.
00:01:28 --> 00:01:30 Professor Fred Watson: Yes, yes, I'm sure it has.
00:01:31 --> 00:01:33 Andrew Dunkley: The reputation continues to spread. we'll be
00:01:33 --> 00:01:36 talking dad jokes in our next episode,
00:01:36 --> 00:01:38 our Q A episode as well.
00:01:39 --> 00:01:41 we should begin with this,
00:01:41 --> 00:01:44 Grail mission and the findings of the moon's
00:01:44 --> 00:01:47 unusual interior. This might
00:01:47 --> 00:01:49 come as a surprise to some people.
00:01:50 --> 00:01:52 Professor Fred Watson: Well, I think it does. Excuse me. I think it
00:01:52 --> 00:01:54 did come as a surprise when the discovery was
00:01:54 --> 00:01:57 made as well. These, are, scientists from
00:01:57 --> 00:01:59 NASA and other institutions, missions.
00:02:01 --> 00:02:03 yeah, let's do the dad joke first. The, It's
00:02:03 --> 00:02:05 not Monty Python and the Holy Grail.
00:02:07 --> 00:02:10 Grail stands for Gravity Recovery and
00:02:10 --> 00:02:13 Interior Laboratory. And it was a mission,
00:02:13 --> 00:02:16 which I guess it was more than. It's probably
00:02:16 --> 00:02:19 a decade ago. it's a very, very
00:02:19 --> 00:02:21 neat piece, of research. And
00:02:21 --> 00:02:24 NASA, you know, the clever stuff that they do
00:02:24 --> 00:02:25 is just unbelievable.
00:02:26 --> 00:02:28 so what do you do if you want to sense the
00:02:28 --> 00:02:31 gravity of, a planet that
00:02:31 --> 00:02:33 you're flying over? You want to map out the
00:02:33 --> 00:02:36 gravitational details. And by doing
00:02:36 --> 00:02:38 that, you can work out what's underneath the
00:02:38 --> 00:02:41 surface. because that's usually what
00:02:41 --> 00:02:43 affects the gravity above the surface of
00:02:44 --> 00:02:47 a planet. And I'm Talking now about really
00:02:48 --> 00:02:50 minor, disorder, differences and
00:02:50 --> 00:02:53 discrepancies in gravity, how the
00:02:53 --> 00:02:56 Grail mission worked. and I'm kind of casting
00:02:56 --> 00:02:59 my memory back now. two spacecraft,
00:02:59 --> 00:03:01 in orbit around the Moon,
00:03:02 --> 00:03:04 separate in the same. They're both in the
00:03:04 --> 00:03:07 same orbit. They were separated, I think, by
00:03:07 --> 00:03:09 about 200 kilometres, one in front of the
00:03:09 --> 00:03:12 other. But the
00:03:12 --> 00:03:15 distance between them could be detected
00:03:15 --> 00:03:17 by microwave transmission
00:03:18 --> 00:03:20 to well under a millimetre. I can't remember
00:03:20 --> 00:03:23 what it was. It was a few microns, I think.
00:03:23 --> 00:03:25 But this tiny, tiny difference between
00:03:26 --> 00:03:29 the position of the two spacecraft, you can
00:03:29 --> 00:03:32 measure it, by these microwave signals. And
00:03:32 --> 00:03:34 so as the two spacecraft go around the moon,
00:03:35 --> 00:03:38 their separation changes slightly as a
00:03:38 --> 00:03:39 result of the gravitational force,
00:03:40 --> 00:03:42 gravitational pull of the terrain beneath
00:03:42 --> 00:03:45 them. and it actually is
00:03:46 --> 00:03:49 a, really very sensitive way. I love the fact
00:03:49 --> 00:03:51 that they rediscovered, something that we
00:03:51 --> 00:03:54 talked about in the very earliest, history of
00:03:54 --> 00:03:57 moon exploration. Back in the, Gemini and
00:03:57 --> 00:03:59 Apollo era, back in the 19, 60s,
00:04:00 --> 00:04:03 mass, cons, which were mass concentrations,
00:04:03 --> 00:04:05 concentrations of mass that were unexpected
00:04:05 --> 00:04:07 underneath the Moon's surface. They were
00:04:07 --> 00:04:09 actually measured just by spacecraft that
00:04:09 --> 00:04:11 were orbiting. Single spacecraft orbiting
00:04:12 --> 00:04:15 the Moon. but, GRAIL actually mapped them out
00:04:15 --> 00:04:17 in much more detail. We know a lot more about
00:04:17 --> 00:04:19 these mascons now than we did before. But
00:04:19 --> 00:04:22 what has happened, and by the way, I should
00:04:22 --> 00:04:25 just mention one, I should have put this in
00:04:25 --> 00:04:27 as a, As a quirky factoid, shouldn't I?
00:04:27 --> 00:04:29 Flippant factoid that the two,
00:04:30 --> 00:04:32 spacecraft, the two components of Grail. Do
00:04:32 --> 00:04:33 you remember what they were called?
00:04:34 --> 00:04:37 Andrew Dunkley: Oh, no.
00:04:37 --> 00:04:40 Professor Fred Watson: Ebb and flow. And it came.
00:04:40 --> 00:04:43 I think it was school kids who did that. If I
00:04:43 --> 00:04:45 remember rightly, NASA sent out a competition
00:04:45 --> 00:04:47 saying, we've got two spacecraft in orbit
00:04:47 --> 00:04:48 around the Moon. What do you want to call
00:04:48 --> 00:04:50 them? And they were called ebb and flow,
00:04:50 --> 00:04:52 which is very, very nice indeed.
00:04:53 --> 00:04:55 Anyway, ebb and flow, in combination,
00:04:55 --> 00:04:58 measured, virtually the gravitational map of
00:04:58 --> 00:05:01 the whole Moon. But what has
00:05:02 --> 00:05:05 come to light is something a little bit
00:05:05 --> 00:05:08 more subtle. these, researchers who've now
00:05:08 --> 00:05:11 used these NASA data to deduce
00:05:11 --> 00:05:13 that There's a, 2 to 3%
00:05:14 --> 00:05:17 difference in the
00:05:17 --> 00:05:20 ability of the lunar mantle. Now, that's
00:05:20 --> 00:05:22 the layer below the crust. That's the
00:05:23 --> 00:05:25 layer that surrounds the core of the Moon.
00:05:25 --> 00:05:28 The ability of the mantle to
00:05:28 --> 00:05:31 deform. So what you're
00:05:31 --> 00:05:34 saying is there's a difference in sort of
00:05:34 --> 00:05:37 flexibility from one side of the Moon to the
00:05:37 --> 00:05:39 other. And remember, as we know The Moon
00:05:39 --> 00:05:41 always faces the same side to Earth. and
00:05:41 --> 00:05:43 so that's, you know, there's a different
00:05:43 --> 00:05:45 gravitational pull on one side from what
00:05:45 --> 00:05:47 there is on the other. but what they've
00:05:47 --> 00:05:49 interpreted this difference as being,
00:05:50 --> 00:05:53 they say it's symptomatic. The fact that
00:05:53 --> 00:05:55 there's this difference in the Moon's mantles
00:05:56 --> 00:05:59 ability to deform, to change its
00:05:59 --> 00:06:02 shape. they say that is
00:06:02 --> 00:06:05 best explained by the
00:06:05 --> 00:06:07 temperature inside the mantle
00:06:08 --> 00:06:10 on the near side being as much
00:06:10 --> 00:06:13 as 170 degrees Celsius
00:06:13 --> 00:06:16 hotter than what it is on the other side.
00:06:16 --> 00:06:18 Wow, that's a side facing us. Yeah, it is.
00:06:18 --> 00:06:20 It's not a small amount, it's not a few
00:06:20 --> 00:06:23 degrees, it's a lot. and it's enough to
00:06:23 --> 00:06:26 change the viscosity of the mantle, how
00:06:26 --> 00:06:29 flexible it is. and so that's
00:06:29 --> 00:06:32 the new finding that's come from ebb
00:06:32 --> 00:06:34 and flow. And I think what they're saying is
00:06:34 --> 00:06:36 that the spacecraft was in orbit for long
00:06:36 --> 00:06:39 enough that it could detect differences in
00:06:39 --> 00:06:41 the gravitational pull as it flew over the
00:06:41 --> 00:06:44 same part of the Moon more than once. It
00:06:44 --> 00:06:46 could see a difference in the gravitational
00:06:46 --> 00:06:48 pull from one trip to another. So there's a
00:06:48 --> 00:06:50 time dependent thing on it, and that's how
00:06:50 --> 00:06:53 they know about the Moon's ability
00:06:53 --> 00:06:55 to deform. I'm actually, interpreting that in
00:06:55 --> 00:06:58 my own way. There's a nice
00:06:58 --> 00:07:01 paper in Nature magazine, perhaps
00:07:01 --> 00:07:03 one of the two leading journals for science
00:07:03 --> 00:07:06 in the world, which has the title of thermal
00:07:06 --> 00:07:09 asymmetry in the Moon's mantle inferred from
00:07:09 --> 00:07:10 monthly tidal response.
00:07:11 --> 00:07:13 Andrew Dunkley: Okay, so my question
00:07:13 --> 00:07:16 straight up is, could that explain,
00:07:16 --> 00:07:19 or does that explain why the near side
00:07:19 --> 00:07:22 and the far side of the Moon are so
00:07:22 --> 00:07:24 very different? when you're talking
00:07:24 --> 00:07:26 topography, yeah, I.
00:07:26 --> 00:07:28 Professor Fred Watson: Think it's the other way around. I suspect
00:07:28 --> 00:07:30 the difference in topography is,
00:07:31 --> 00:07:33 what causes the difference. Although they're
00:07:33 --> 00:07:36 probably all mishmashed up,
00:07:38 --> 00:07:40 into the same sort of thing.
00:07:41 --> 00:07:42 But the Moon's nearside,
00:07:43 --> 00:07:45 I think probably the way you've put it,
00:07:45 --> 00:07:47 actually Andrew, is probably more correct.
00:07:47 --> 00:07:50 The Moon's nearside, has had much
00:07:50 --> 00:07:53 more volcanic activity than the far side.
00:07:53 --> 00:07:56 This is between 3 and 4 billion years ago. It
00:07:56 --> 00:07:58 was highly volcanically active, which is why
00:07:58 --> 00:08:00 we've got all these lava flows on the near
00:08:00 --> 00:08:03 side, which we see as the maria, the grey
00:08:03 --> 00:08:06 patches on the Moon. but the
00:08:06 --> 00:08:08 details of what these
00:08:08 --> 00:08:11 researchers think, contributes to
00:08:11 --> 00:08:14 the difference, in temperature, they
00:08:14 --> 00:08:17 suggest I might actually, I think this is
00:08:17 --> 00:08:19 Nature's press release So I might just read
00:08:19 --> 00:08:20 straight from it.
00:08:22 --> 00:08:25 they hypothesise that this thermal
00:08:25 --> 00:08:28 difference could be sustained by radioactive
00:08:28 --> 00:08:31 decay of thorium and titanium within the
00:08:31 --> 00:08:33 moon's near side, which could be a
00:08:33 --> 00:08:36 remnant of the volcanic activity that formed
00:08:36 --> 00:08:38 the near side surface 3 to 4 billion years
00:08:38 --> 00:08:39 ago.
00:08:40 --> 00:08:42 Andrew Dunkley: That is really interesting. Yeah,
00:08:43 --> 00:08:46 I'm fascinated
00:08:46 --> 00:08:48 by a couple of things, that we're using old
00:08:48 --> 00:08:50 data to make new discoveries. We've talked
00:08:50 --> 00:08:52 about that in other studies that have more
00:08:52 --> 00:08:54 papers that have been released in recent
00:08:54 --> 00:08:57 years. also the fact that there's
00:08:57 --> 00:09:00 effects on the moon that we see in
00:09:00 --> 00:09:02 other parts of the solar system, with, with
00:09:03 --> 00:09:05 variations in the way the moons
00:09:07 --> 00:09:09 interact with their host planet for example.
00:09:09 --> 00:09:10 I suppose.
00:09:10 --> 00:09:11 Professor Fred Watson: Yes.
00:09:11 --> 00:09:13 Andrew Dunkley: It's a similar situation is it not?
00:09:13 --> 00:09:15 Professor Fred Watson: Yes, that's right. So you've got and in fact
00:09:15 --> 00:09:18 most of these moons around, certainly the
00:09:18 --> 00:09:21 giant planets are ah, which is where most of
00:09:21 --> 00:09:23 the moons in the solar system are. there's
00:09:23 --> 00:09:25 only three in the inner solar system. Ours
00:09:25 --> 00:09:28 and Mars is two little satellites.
00:09:28 --> 00:09:31 But places like Enceladus, Ganymede, perhaps
00:09:31 --> 00:09:34 Callisto, Europa, around Jupiter, perhaps
00:09:34 --> 00:09:36 Titan as well, they,
00:09:37 --> 00:09:40 they could do use
00:09:40 --> 00:09:43 this technology to
00:09:44 --> 00:09:46 actually interpret what's going on
00:09:46 --> 00:09:49 inside these worlds without having to land
00:09:49 --> 00:09:52 a spacecraft on the surface. That's the,
00:09:52 --> 00:09:54 the great thing because putting something
00:09:54 --> 00:09:56 into orbit around Enceladus for example,
00:09:57 --> 00:10:00 would be much more straightforward, much
00:10:00 --> 00:10:03 less energy hungry than putting a
00:10:03 --> 00:10:05 spacecraft down onto the surface where you've
00:10:05 --> 00:10:08 got all the risks of collisions and tipping
00:10:08 --> 00:10:10 over like several of the lunar probes have
00:10:10 --> 00:10:13 done, they've fallen over. all of that is
00:10:13 --> 00:10:16 the hazard when you're landing something on
00:10:16 --> 00:10:19 the surface. So yeah, I think it's got a
00:10:19 --> 00:10:22 future. Now. you can, as I
00:10:22 --> 00:10:24 kind of mentioned earlier, you can do some of
00:10:24 --> 00:10:27 this kind of work with a single spacecraft,
00:10:27 --> 00:10:29 but if you can launch two with this
00:10:29 --> 00:10:31 microwave, microwave bridge between them,
00:10:31 --> 00:10:34 then you can do much, much more as the
00:10:34 --> 00:10:36 Grail spacecraft demonstrated.
00:10:36 --> 00:10:39 Andrew Dunkley: Okay, so yeah, the moon is not as
00:10:39 --> 00:10:42 it seems, at least not on the inside.
00:10:42 --> 00:10:45 Professor Fred Watson: Well no, that's right. Or maybe, maybe it is
00:10:45 --> 00:10:48 as it seems because the two sides are so
00:10:48 --> 00:10:50 different when you look at them. As you said,
00:10:50 --> 00:10:53 the topography is quite different from one
00:10:53 --> 00:10:54 side to the other.
00:10:54 --> 00:10:56 Andrew Dunkley: It's a great story. If you'd like to read up
00:10:56 --> 00:10:58 on that, you can find, you can go find the
00:10:58 --> 00:11:00 paper if you can remember the title of it
00:11:00 --> 00:11:02 because it's got more than three words in it.
00:11:02 --> 00:11:04 So I'm stuffed. But yeah,
00:11:04 --> 00:11:06 DailyGalaxy.com is the website.
00:11:06 --> 00:11:09 DailyGalaxy.com this is
00:11:09 --> 00:11:12 space Nuts with Andrew Dunkley and Professor
00:11:12 --> 00:11:13 Fred Watson Watson.
00:11:16 --> 00:11:18 Three, two, one.
00:11:18 --> 00:11:20 Professor Fred Watson: Space Nuts.
00:11:20 --> 00:11:23 Andrew Dunkley: Fred Watson, I neglected to mention my office
00:11:23 --> 00:11:26 background at the beginning. if I just put my
00:11:26 --> 00:11:29 thumb over the camera, people on YouTube will
00:11:29 --> 00:11:31 see a massive mountain there. That's the Fugo
00:11:31 --> 00:11:34 volcano in Guatemala. I took that photo on
00:11:34 --> 00:11:37 the 7th of April. And Judy and
00:11:37 --> 00:11:39 I have a history of visiting volcanoes,
00:11:39 --> 00:11:40 getting home and then finding out they
00:11:40 --> 00:11:42 started erupting. And that's exactly what's
00:11:42 --> 00:11:45 happened with Fugo. So if you're on YouTube
00:11:45 --> 00:11:47 and you're watching us, when we're finished,
00:11:47 --> 00:11:49 go and have a look at some of the eruption
00:11:49 --> 00:11:52 footage from the Fugo volcano in Guatemala at
00:11:52 --> 00:11:55 the moment. It is spectacular. We had to
00:11:55 --> 00:11:57 drive between three volcanoes to
00:11:57 --> 00:12:00 get to the township of Antigua
00:12:00 --> 00:12:03 and you could see these things for
00:12:03 --> 00:12:05 miles. I mean they're strata volcanoes, they
00:12:05 --> 00:12:08 are absolutely enormous. They're
00:12:08 --> 00:12:11 around 12, 13ft at the peak
00:12:11 --> 00:12:14 above sea level. and they
00:12:14 --> 00:12:16 are spectacular. And we literally had to
00:12:16 --> 00:12:18 drive between two of them to get to the town.
00:12:19 --> 00:12:21 That one was on our left and the
00:12:21 --> 00:12:24 agua volcano was on our right. and
00:12:24 --> 00:12:26 the town is in the foothills of the the two
00:12:27 --> 00:12:29 nearest volcanoes. And it's just an
00:12:29 --> 00:12:32 awe inspiring sight. But I just thought it
00:12:32 --> 00:12:34 was funny that well maybe not funny haha, but
00:12:34 --> 00:12:37 funny that we went to Hawaii, got home
00:12:37 --> 00:12:40 and Kilauea erupted. Happens a lot.
00:12:40 --> 00:12:43 I went to Vanuatu, Matt Yasser, got home, it
00:12:43 --> 00:12:45 erupted and stopped air traffic for a couple
00:12:45 --> 00:12:48 of weeks. And now this one's erupting a month
00:12:48 --> 00:12:50 after we were there. So we're not going to be
00:12:50 --> 00:12:52 invited back I don't think. But
00:12:53 --> 00:12:55 Fugo's got a history though it erupts quite
00:12:55 --> 00:12:57 often. But I just thought people would be
00:12:57 --> 00:13:00 interested to see a photo of it. as you know,
00:13:00 --> 00:13:01 I'm a volcano junkie.
00:13:02 --> 00:13:04 Professor Fred Watson: So when we were in Iceland earlier in the
00:13:04 --> 00:13:07 year, the Reykjanes peninsula had
00:13:07 --> 00:13:10 just erupted as well. Well here there was
00:13:10 --> 00:13:12 a lot of steam coming up from from the, you
00:13:12 --> 00:13:14 know, the fishes in the ground.
00:13:14 --> 00:13:16 Andrew Dunkley: Yeah. In the next few months we'll be
00:13:16 --> 00:13:18 visiting the Canary Islands.
00:13:19 --> 00:13:19 Professor Fred Watson: Sure.
00:13:20 --> 00:13:23 Andrew Dunkley: Yeah. So that one's got an active volcano
00:13:23 --> 00:13:25 and we're visiting Iceland as well.
00:13:26 --> 00:13:28 yeah. Could, could have some stories to tell.
00:13:28 --> 00:13:29 Professor Fred Watson: Yeah.
00:13:29 --> 00:13:32 Andrew Dunkley: Ah, good. Okay Fred Watson, let's move on
00:13:32 --> 00:13:32 to our next story.
00:13:32 --> 00:13:35 And this one is about yet again,
00:13:36 --> 00:13:39 the Hubble tension, the, the
00:13:39 --> 00:13:41 quirk of space that we
00:13:42 --> 00:13:44 can't quite get our heads around. We can't
00:13:44 --> 00:13:47 solve the differentials or the problems. Many
00:13:47 --> 00:13:49 are saying, look, it's natural. But
00:13:50 --> 00:13:52 Now another Hubble
00:13:52 --> 00:13:54 Tension theory, gee that's hard to say.
00:13:56 --> 00:13:59 is making its way into various papers. one in
00:13:59 --> 00:14:01 particular I suspect, because now they're
00:14:01 --> 00:14:04 talking about evolution in
00:14:04 --> 00:14:06 dark matter. This sounds like
00:14:07 --> 00:14:10 pie in the sky type stuff but we've got
00:14:10 --> 00:14:11 to, we've got to come up with answers. The
00:14:11 --> 00:14:14 only way it is to publish papers with
00:14:14 --> 00:14:16 theories and you know,
00:14:16 --> 00:14:17 toss it around.
00:14:19 --> 00:14:19 Professor Fred Watson: Indeed.
00:14:19 --> 00:14:22 Andrew Dunkley: That's like, like a salad. A space
00:14:22 --> 00:14:23 salad.
00:14:25 --> 00:14:27 Professor Fred Watson: yeah, I've just I'm m hesitating because I've
00:14:27 --> 00:14:29 just seen who one of the authors of this
00:14:29 --> 00:14:29 paper is.
00:14:32 --> 00:14:34 it's a scientist who's known for
00:14:34 --> 00:14:37 provocative papers. Avi
00:14:37 --> 00:14:40 Loeb, and he's at Harvard, Smithsonian,
00:14:41 --> 00:14:44 Centre for Astrophysics. So the
00:14:44 --> 00:14:45 paper that we're talking about is called
00:14:45 --> 00:14:48 Evolving Dark Energy or Evolving Dark
00:14:48 --> 00:14:51 Matter. and this
00:14:51 --> 00:14:53 is really esoteric stuff, Andrew.
00:14:54 --> 00:14:55 Always when we're talking about this stuff
00:14:56 --> 00:14:58 we're just glossing over
00:14:59 --> 00:15:01 a lot of really detailed
00:15:02 --> 00:15:05 science that goes into
00:15:05 --> 00:15:08 realms that even I struggle with. And I'm not
00:15:08 --> 00:15:10 actually a cosmologist, which is why. But
00:15:10 --> 00:15:12 I'm supposed to know my way around some of
00:15:12 --> 00:15:15 these topics better than perhaps
00:15:15 --> 00:15:17 the person in the street is.
00:15:18 --> 00:15:21 and this
00:15:21 --> 00:15:22 comes down to something called the equation
00:15:22 --> 00:15:24 of states which you and I haven't talked
00:15:24 --> 00:15:27 about. But the equation of state is a
00:15:27 --> 00:15:30 parameter in the universe. It's a parameter
00:15:30 --> 00:15:32 generally. It comes from thermodynamics,
00:15:33 --> 00:15:36 which essentially characterises,
00:15:37 --> 00:15:39 as the name almost implies, it
00:15:39 --> 00:15:42 characterises the overall behaviour of the
00:15:42 --> 00:15:44 universe. The equation of states, okay,
00:15:44 --> 00:15:46 Symbolised by the, the character W.
00:15:49 --> 00:15:52 so the, the work that's
00:15:52 --> 00:15:54 being reported here. and as I've said
00:15:54 --> 00:15:57 it's on a, on a, there's a, there's a.
00:15:58 --> 00:16:01 Basically a preprint as we used
00:16:01 --> 00:16:03 to call them. this is a paper that's not yet
00:16:03 --> 00:16:06 been refereed which is
00:16:07 --> 00:16:10 going to go into. I can't see
00:16:10 --> 00:16:13 what journal it's aiming for but it
00:16:13 --> 00:16:14 is called
00:16:15 --> 00:16:18 essentially the title of the paper Evolving
00:16:18 --> 00:16:20 Dark Energy or Evolving Dark Matter. I'm
00:16:20 --> 00:16:22 going to read you the abstract, okay?
00:16:23 --> 00:16:26 because that kind of tells the story even
00:16:26 --> 00:16:29 if you don't know what the details are.
00:16:29 --> 00:16:31 We show that the latest
00:16:32 --> 00:16:35 empirical constraints on cosmology, and by
00:16:35 --> 00:16:37 that they mean measured, from a Combination
00:16:37 --> 00:16:40 of desi, that's the Dark Energy Survey
00:16:40 --> 00:16:43 instrument cmb, that's the cosmic
00:16:43 --> 00:16:45 microwave background and supernova data,
00:16:45 --> 00:16:48 that's exploding stars. They've taken all
00:16:48 --> 00:16:51 this data together. The empirical
00:16:51 --> 00:16:52 constraints on cosmology from that
00:16:52 --> 00:16:55 combination can be accounted for. If
00:16:55 --> 00:16:58 a small component of dark matter
00:16:59 --> 00:17:02 has an evolving and oscillating
00:17:02 --> 00:17:05 equation of state within the range minus
00:17:05 --> 00:17:08 1 is greater than less than w, which is
00:17:08 --> 00:17:11 less than 1, that's the range minus 1 to 1 is
00:17:11 --> 00:17:13 somewhere where this equation of state
00:17:13 --> 00:17:16 parameter, W lies. From a fundamental physics
00:17:16 --> 00:17:18 perspective, this interpretation is more
00:17:18 --> 00:17:21 appealing than an evolving phantom
00:17:21 --> 00:17:24 dark energy with W less than minus
00:17:24 --> 00:17:26 1, which violates the null energy
00:17:26 --> 00:17:29 condition. So in a sense
00:17:29 --> 00:17:32 this paper is kind of in response
00:17:33 --> 00:17:35 to what we're seeing from the latest data
00:17:35 --> 00:17:38 actually from desi, the Dark Energy Survey,
00:17:39 --> 00:17:42 which suggests that dark
00:17:42 --> 00:17:45 energy is getting less.
00:17:45 --> 00:17:47 Or at least what it suggests is the
00:17:47 --> 00:17:50 acceleration of the universe's expansion is
00:17:50 --> 00:17:52 getting less. In other words, the expansion
00:17:52 --> 00:17:54 which we know is accelerating because that's
00:17:54 --> 00:17:57 been well measured. But the suggestion is
00:17:57 --> 00:18:00 that that acceleration is slowing down,
00:18:00 --> 00:18:03 so as time goes on it will be accelerating at
00:18:03 --> 00:18:06 a lower rate. What they're saying is,
00:18:07 --> 00:18:09 when you look at the sort of theory that
00:18:09 --> 00:18:12 doesn't make sense, but it makes more sense
00:18:12 --> 00:18:15 if something is going on with
00:18:15 --> 00:18:18 dark matter, that dark matter,
00:18:19 --> 00:18:21 is itself evolving. Now
00:18:22 --> 00:18:25 that suggests, and they apparently
00:18:25 --> 00:18:27 explore this in the paper, I haven't read the
00:18:27 --> 00:18:30 paper, but they explore this, that suggests
00:18:30 --> 00:18:33 that dark matter is something different from
00:18:33 --> 00:18:35 what we think it is because we imagine dark
00:18:35 --> 00:18:38 matter as being some subatomic particle,
00:18:38 --> 00:18:41 which is as yet unknown, which does not
00:18:41 --> 00:18:43 interact with normal matter at all, which is
00:18:43 --> 00:18:46 why we can't see it, and all it reveals
00:18:46 --> 00:18:49 itself by is its gravity. That's the
00:18:49 --> 00:18:51 parameters that we understand dark matter to
00:18:51 --> 00:18:54 be. But what they're suggesting
00:18:54 --> 00:18:57 is that this is something even more
00:18:57 --> 00:19:00 exotic than we have been imagining,
00:19:00 --> 00:19:03 because its parameters
00:19:03 --> 00:19:06 change, its phenomena change and
00:19:06 --> 00:19:09 that leads to a changed equation of state,
00:19:09 --> 00:19:11 the W parameter.
00:19:14 --> 00:19:16 And they actually suggest,
00:19:17 --> 00:19:19 that actually there's some sort of
00:19:19 --> 00:19:22 oscillation going on in it as well. Not just
00:19:22 --> 00:19:25 dark matter. There's a very nice article on
00:19:25 --> 00:19:26 physics phys.org
00:19:28 --> 00:19:30 by Brian Koberlein. I'm going to read
00:19:30 --> 00:19:32 a paragraph for it.
00:19:34 --> 00:19:36 in fact I'm going to read a couple,
00:19:37 --> 00:19:39 let me just read from this because I think
00:19:39 --> 00:19:41 that's going to explain it better than me
00:19:41 --> 00:19:44 waffling on. In work published on the
00:19:44 --> 00:19:46 Arxivist print server, the Authors look at
00:19:46 --> 00:19:49 both evolving dark energy and evolving dark
00:19:49 --> 00:19:52 matter and argue that the latter is a much
00:19:52 --> 00:19:54 better fit to the observational data. The
00:19:54 --> 00:19:55 first thing they know is that the two models
00:19:55 --> 00:19:58 are somewhat related. Since the evolution of
00:19:58 --> 00:20:01 the cosmos depends in part on the ratio of
00:20:01 --> 00:20:04 dark energy to matter density, a model
00:20:04 --> 00:20:06 with constant dark matter, which is what we
00:20:06 --> 00:20:08 have at the moment, and evolving dark energy,
00:20:09 --> 00:20:12 will always appear similar to a model with
00:20:12 --> 00:20:14 evolving dark matter and a constant dark
00:20:14 --> 00:20:17 energy. That's a good point. They then go on
00:20:17 --> 00:20:19 to explore the idea of some kind of exotic
00:20:19 --> 00:20:21 dark matter, one that has a changeable
00:20:21 --> 00:20:23 equation of state to match observation. The
00:20:23 --> 00:20:26 dark matter equation of state must
00:20:26 --> 00:20:29 oscillate in time. This isn't an
00:20:29 --> 00:20:31 outlandish notion. I think
00:20:31 --> 00:20:33 they're trying to convince us here in
00:20:33 --> 00:20:36 space.org neutrinos have mass
00:20:36 --> 00:20:39 and don't interact strongly with light. While
00:20:39 --> 00:20:40 they can't account for all the dark matter in
00:20:40 --> 00:20:43 the universe, they are a form of hot dark
00:20:43 --> 00:20:45 matter. And neutrinos undergo, mass
00:20:45 --> 00:20:48 oscillation. Perhaps cold and dark
00:20:48 --> 00:20:51 matter particles undergo, Sorry. Perhaps cold
00:20:51 --> 00:20:53 dark matter particles undergo a similar
00:20:54 --> 00:20:57 oscillatory, effect. The authors find
00:20:58 --> 00:21:00 that the best fit to observational data is a
00:21:00 --> 00:21:03 universe where about 15% of the cold dark
00:21:03 --> 00:21:05 matter is oscillatory, and the
00:21:05 --> 00:21:08 remaining 85% is standard dark
00:21:08 --> 00:21:11 matter. This would allow for the Hubble
00:21:11 --> 00:21:14 tension to be covered while still matching
00:21:14 --> 00:21:16 the dark matter observations we have.
00:21:16 --> 00:21:18 And I love the last paragraph.
00:21:18 --> 00:21:20 Andrew Dunkley: Yeah, I do too. I was just reading it.
00:21:20 --> 00:21:23 Professor Fred Watson: It should be stressed that this work presents
00:21:23 --> 00:21:26 a toy model. As the authors themselves note,
00:21:26 --> 00:21:28 the work is a broad concept that does not pin
00:21:28 --> 00:21:30 down specific constraints for dark matter
00:21:30 --> 00:21:32 particles. But the work does open the door to
00:21:32 --> 00:21:34 a broader range of dark matter models. At
00:21:34 --> 00:21:36 this point, evolving dark matter is worth
00:21:36 --> 00:21:38 considering. Well, I agree with that. I think
00:21:38 --> 00:21:40 everything's worth calling.
00:21:40 --> 00:21:42 Andrew Dunkley: I was going to ask you where you stand on
00:21:42 --> 00:21:44 this and if it's worth considering, then
00:21:44 --> 00:21:47 obviously it is. But it
00:21:47 --> 00:21:49 just adds another potential
00:21:50 --> 00:21:53 explanation of something we know very little
00:21:53 --> 00:21:54 about and.
00:21:54 --> 00:21:57 Professor Fred Watson: Yep. And we worry about a lot, especially
00:21:57 --> 00:21:58 on space. Nuts.
00:21:58 --> 00:22:01 Andrew Dunkley: Yes, yes. And we get a lot of questions about
00:22:01 --> 00:22:03 it. And so a lot of people thinking about
00:22:03 --> 00:22:06 this stuff, if it's, if it's in fact
00:22:06 --> 00:22:06 stuff.
00:22:07 --> 00:22:09 Professor Fred Watson: Yes, well, yes, that's right. It could be
00:22:09 --> 00:22:10 something other than stuff.
00:22:10 --> 00:22:13 Andrew Dunkley: Yes, yes. So, yeah, it's a
00:22:13 --> 00:22:16 really interesting idea and, well, I
00:22:16 --> 00:22:18 suppose, it'll get tossed around and people
00:22:18 --> 00:22:20 will come up with other explanations. But the
00:22:20 --> 00:22:23 thing is, a paper like this, even if it's
00:22:23 --> 00:22:26 wrong may spawn a level of thinking
00:22:26 --> 00:22:28 that might send us down a path where we might
00:22:28 --> 00:22:29 eventually figure it out. I mean that's
00:22:29 --> 00:22:30 another possibility.
00:22:31 --> 00:22:33 Professor Fred Watson: that's, that's true. That's correct.
00:22:34 --> 00:22:36 and that's the way science works as well.
00:22:36 --> 00:22:37 Exactly as you've said.
00:22:37 --> 00:22:38 Yes, indeed.
00:22:38 --> 00:22:41 Andrew Dunkley: All right. as Fred Watson said, you can read
00:22:41 --> 00:22:44 all about it@the phys.org website. That's
00:22:44 --> 00:22:47 P-Y-S.org or you can
00:22:47 --> 00:22:49 read the published paper on the archive
00:22:49 --> 00:22:52 reprint server if you like. This is Space
00:22:52 --> 00:22:54 Nuts. Andrew Dunkley here, Fred Watson Watson
00:22:54 --> 00:22:54 there.
00:22:57 --> 00:22:58 Okay, we checked all four systems.
00:23:01 --> 00:23:03 Our final topic today, Fred Watson,
00:23:04 --> 00:23:06 is a really interesting one and it
00:23:06 --> 00:23:09 is going to take us to the Kuiper
00:23:09 --> 00:23:09 Belt.
00:23:09 --> 00:23:12 So tighten up your buckle and get ready for
00:23:12 --> 00:23:15 this one because we think there has
00:23:15 --> 00:23:18 been discovered a triple system in the Kuiper
00:23:18 --> 00:23:21 Belt. Now when we talk about the Kuiper
00:23:21 --> 00:23:24 Belt we don't really, we've only been there a
00:23:24 --> 00:23:27 couple of times. fairly recent missions in
00:23:27 --> 00:23:30 the last decade or so. But we've only had
00:23:30 --> 00:23:33 close up observations of two objects
00:23:33 --> 00:23:35 in the Kuiper Belt. So
00:23:36 --> 00:23:39 this discovery was actually made not by
00:23:39 --> 00:23:42 either of those probes but, or the
00:23:42 --> 00:23:44 probe in question. it was made from
00:23:44 --> 00:23:46 Earth, am I correct?
00:23:46 --> 00:23:49 Professor Fred Watson: Yes, that's right. using the Hubble
00:23:49 --> 00:23:50 Space Telescope.
00:23:50 --> 00:23:51 Andrew Dunkley: Yeah.
00:23:52 --> 00:23:54 Professor Fred Watson: Which is you know, still going strong
00:23:54 --> 00:23:57 and still a
00:23:57 --> 00:23:58 fantastic resource
00:24:00 --> 00:24:02 given that it's now 35 years
00:24:03 --> 00:24:05 in space. Yes, it is amazing. That's
00:24:05 --> 00:24:08 right. so, and again this is a team
00:24:08 --> 00:24:11 of researchers from NASA. what they've been
00:24:11 --> 00:24:13 doing is looking through ah, Hubble
00:24:13 --> 00:24:16 telescope data at this very distant
00:24:17 --> 00:24:19 object which is it's a,
00:24:20 --> 00:24:21 an asteroid. So it's got a number
00:24:21 --> 00:24:24 148780 and
00:24:24 --> 00:24:27 it's known as Algeria. that's its name.
00:24:27 --> 00:24:30 and they, they,
00:24:31 --> 00:24:33 they haven't seen the three
00:24:33 --> 00:24:36 bodies that they now think make it up, but
00:24:36 --> 00:24:37 they've seen two.
00:24:37 --> 00:24:38 Andrew Dunkley: Wait, dad, joke coming.
00:24:39 --> 00:24:40 Professor Fred Watson: Oh good. Okay. They're seeing two of them.
00:24:42 --> 00:24:43 Andrew Dunkley: I was going so they haven't seen the three
00:24:43 --> 00:24:44 bodies. That's a problem.
00:24:45 --> 00:24:48 Professor Fred Watson: Oh, there we go. Love it. Love
00:24:48 --> 00:24:51 it. I
00:24:51 --> 00:24:52 don't understand. You must rehearse our
00:24:52 --> 00:24:54 conversations weeks in advance, Andrew, to
00:24:54 --> 00:24:55 get.
00:24:55 --> 00:24:57 Andrew Dunkley: No, the scary part is this
00:24:57 --> 00:24:59 garbage just pops in there
00:25:00 --> 00:25:03 at random moments. It used to happen
00:25:03 --> 00:25:05 when I was on the radio. I'd just be talking
00:25:05 --> 00:25:08 about something and a little voice ago,
00:25:08 --> 00:25:09 hey, tell this joke.
00:25:10 --> 00:25:12 Professor Fred Watson: Yeah. And then at the end of it you think I
00:25:12 --> 00:25:14 got a Wish I hadn't said that.
00:25:15 --> 00:25:15 Yes, yeah.
00:25:15 --> 00:25:17 Andrew Dunkley: Ah, yeah, yeah.
00:25:17 --> 00:25:20 Professor Fred Watson: Anyway, so it's, it,
00:25:20 --> 00:25:23 it basically is new, ah, research.
00:25:23 --> 00:25:25 And so, so they can see two. They can
00:25:25 --> 00:25:27 detect that there are two objects
00:25:28 --> 00:25:29 orbiting one another.
00:25:30 --> 00:25:31 Andrew Dunkley: I sent the but.
00:25:32 --> 00:25:35 Professor Fred Watson: The butt is. Yes, yes. the
00:25:35 --> 00:25:37 but is that it looks as though one of them is
00:25:37 --> 00:25:40 actually a pair of objects. That's the trick.
00:25:41 --> 00:25:44 So we've got two things that have been
00:25:44 --> 00:25:46 seen, but one of them is
00:25:46 --> 00:25:49 probably a double. And they've had to
00:25:49 --> 00:25:52 use the very detailed,
00:25:52 --> 00:25:54 measurements of the way
00:25:55 --> 00:25:58 the object that they can see orbits the other
00:25:58 --> 00:26:00 one, the way that orbit changes.
00:26:01 --> 00:26:03 that is what tells you that the
00:26:04 --> 00:26:06 central object, if I can put it that way,
00:26:06 --> 00:26:09 might actually be two. and so it's
00:26:09 --> 00:26:11 the outer object, its orbit
00:26:11 --> 00:26:14 changes over time. And it's that change,
00:26:15 --> 00:26:18 that allows the deduction that the central
00:26:18 --> 00:26:21 object, if I put it that way, is.
00:26:23 --> 00:26:25 Well, they say it's either extremely
00:26:25 --> 00:26:28 elongated or it's two separate objects.
00:26:29 --> 00:26:31 And that, you know, the odds are that it is
00:26:31 --> 00:26:34 actually probably two. often though,
00:26:34 --> 00:26:36 we've got this situation, especially with
00:26:36 --> 00:26:39 these distant, asteroids,
00:26:40 --> 00:26:43 where you have clearly something that
00:26:43 --> 00:26:46 has been a binary, two objects in orbit
00:26:46 --> 00:26:47 around one another, but they've gradually,
00:26:48 --> 00:26:51 collapsed together, not in a violent way,
00:26:51 --> 00:26:54 and wound up in contact, which is something
00:26:54 --> 00:26:56 we call, believe it or not, a contact binary.
00:26:56 --> 00:26:59 And Arrokoth, it's one of the Kuiper Belt
00:26:59 --> 00:27:02 objects that you actually just referred to.
00:27:02 --> 00:27:04 It's beyond the orbit of Pluto. It was
00:27:04 --> 00:27:06 visited by New Horizons. when we saw it, it
00:27:06 --> 00:27:08 looked like a snowman. And that was very
00:27:08 --> 00:27:10 seasonal because I think it was Christmas
00:27:10 --> 00:27:13 time, when it was discovered. But the
00:27:13 --> 00:27:16 analysis of, New Horizons data as it
00:27:16 --> 00:27:18 flew past Arrokoth showed that it wasn't
00:27:18 --> 00:27:20 actually two balls joined together. It was
00:27:20 --> 00:27:22 two pancakes joined together, rim to rim,
00:27:23 --> 00:27:25 so that it actually looked like a snowman,
00:27:25 --> 00:27:27 but from the edge on, it looked a lot more
00:27:27 --> 00:27:30 like two pancakes stuck together. But that's
00:27:30 --> 00:27:32 a common phenomenon. Two objects, whatever
00:27:32 --> 00:27:34 their shape, is coming together gently and
00:27:34 --> 00:27:37 actually, basically cementing
00:27:37 --> 00:27:39 themselves together just by gravity. But then
00:27:39 --> 00:27:42 the sort of gap between them fills in and you
00:27:42 --> 00:27:43 end up with something that looks like a
00:27:43 --> 00:27:46 peanut. So I think it's still possible
00:27:47 --> 00:27:50 that Algeria could have that sort
00:27:50 --> 00:27:53 of shape. But they actually say,
00:27:53 --> 00:27:55 the research team who's done this, they say
00:27:56 --> 00:27:59 that the triple system actually fits the data
00:27:59 --> 00:28:01 best. it fits it better
00:28:02 --> 00:28:05 than a contact binary or a really elongated
00:28:05 --> 00:28:08 central object. So a triple system is what we
00:28:08 --> 00:28:11 Believe it is, it's a very nice target for
00:28:11 --> 00:28:13 a future mission to the outer solar system,
00:28:13 --> 00:28:15 but that's not going to happen anytime soon.
00:28:16 --> 00:28:18 but, yeah, so, very nice discovery. Triple
00:28:18 --> 00:28:21 systems are rare. That's why, that's why it,
00:28:21 --> 00:28:23 you know, it's making the headlines. These
00:28:23 --> 00:28:26 are rare phenomena. Binaries are very common.
00:28:27 --> 00:28:29 In fact, probably most objects out there in
00:28:29 --> 00:28:31 this outer solar system might be binaries,
00:28:31 --> 00:28:32 but triple systems are rare.
00:28:33 --> 00:28:36 Andrew Dunkley: interestingly, this, rock, if you want to
00:28:36 --> 00:28:39 call it that, or system Algeria,
00:28:39 --> 00:28:41 is much, much bigger than Arrokoth. it's,
00:28:42 --> 00:28:44 about 124 miles wide, or 200
00:28:44 --> 00:28:46 kilometres. That's a big chunk.
00:28:47 --> 00:28:49 Professor Fred Watson: Yes, it is, yes. A lot, more substantial than
00:28:49 --> 00:28:51 Arrokoth, which was only, if I remember
00:28:51 --> 00:28:52 right, it was less than a kilometre, I think.
00:28:53 --> 00:28:55 it's amazing that they found it at all. To
00:28:56 --> 00:28:59 give New Horizons a target beyond, Pluto.
00:29:00 --> 00:29:02 Andrew Dunkley: Yeah, yeah, as you say, we're probably not
00:29:02 --> 00:29:04 going to go back out there in a hurry. These
00:29:04 --> 00:29:07 missions are very long winded
00:29:07 --> 00:29:09 because of the distances involved. We're
00:29:09 --> 00:29:12 talking what, 30 or 30
00:29:12 --> 00:29:14 AU or something?
00:29:14 --> 00:29:16 Professor Fred Watson: Yeah, I think this is more, I think it's more
00:29:16 --> 00:29:18 like 45 AU or something like that. So it's.
00:29:18 --> 00:29:21 Yeah, AU is an astronomical unit,
00:29:21 --> 00:29:23 150 million kilometres.
00:29:23 --> 00:29:25 Andrew Dunkley: Yeah, that's a long way away. but
00:29:26 --> 00:29:29 yeah, it's probably an area of our
00:29:29 --> 00:29:31 solar system, even though it's so remote,
00:29:31 --> 00:29:34 that we need to learn more about because, you
00:29:34 --> 00:29:36 know, some of these rocks get
00:29:36 --> 00:29:38 bumped and end up heading our way.
00:29:39 --> 00:29:42 Professor Fred Watson: yes, that's right, they do, or, you know,
00:29:42 --> 00:29:44 gravitationally interact with other objects.
00:29:44 --> 00:29:47 but you're right, in some
00:29:47 --> 00:29:49 ways it's the last frontier. It's completing
00:29:49 --> 00:29:52 the evidence for the way we think. Our
00:29:52 --> 00:29:55 solar system formed by this icy,
00:29:55 --> 00:29:58 dust and gas cloud that collapsed. And a
00:29:58 --> 00:30:01 lot of this stuff is the last vestiges, the
00:30:01 --> 00:30:03 outer, the outer vestiges of those,
00:30:04 --> 00:30:06 you know, those, objects that eventually went
00:30:06 --> 00:30:08 up to make the inner planets. These are,
00:30:08 --> 00:30:10 these are worlds that have never been heated.
00:30:10 --> 00:30:12 And that's the, you know, the planets have
00:30:12 --> 00:30:15 been, they've been bombarded by gravitational
00:30:16 --> 00:30:19 interactions by collisions and, impacts
00:30:19 --> 00:30:20 and things of that sort, so that they're hot.
00:30:21 --> 00:30:23 these worlds have always been cold and that's
00:30:23 --> 00:30:25 why they're so interesting, because they're
00:30:25 --> 00:30:27 sort of the fossil of the solar system's
00:30:27 --> 00:30:28 earliest history.
00:30:28 --> 00:30:29 Andrew Dunkley: Yeah. Yeah.
00:30:29 --> 00:30:31 Well, I guess the time will come where we do
00:30:31 --> 00:30:33 extensive studies, but, I think we'll have to
00:30:33 --> 00:30:36 get better spacecraft and maybe use
00:30:36 --> 00:30:38 those, superhighways you were talking about.
00:30:38 --> 00:30:39 Professor Fred Watson: Yeah, yeah, that's right.
00:30:39 --> 00:30:41 Andrew Dunkley: Get out there and have a look.
00:30:41 --> 00:30:41 Professor Fred Watson: Yes.
00:30:41 --> 00:30:43 Andrew Dunkley: if you'd like to read up on that, you can do
00:30:43 --> 00:30:46 that at the NASA science website or you can
00:30:46 --> 00:30:49 go, to the study itself, which was published
00:30:49 --> 00:30:51 in the Planetary Science Journal.
00:30:52 --> 00:30:54 that brings us to the end. Fred, thank you so
00:30:54 --> 00:30:54 much.
00:30:55 --> 00:30:57 Professor Fred Watson: it's a pleasure, Andrew. a nice surprise to
00:30:57 --> 00:30:59 see you and, always a pleasure to talk.
00:31:00 --> 00:31:02 Andrew Dunkley: Good to see you too. And we'll catch you on
00:31:02 --> 00:31:04 the very next episode. Don't forget to visit
00:31:04 --> 00:31:06 us online. In the meantime, we've got, plenty
00:31:06 --> 00:31:09 of platforms. We're on Instagram, we're on
00:31:09 --> 00:31:11 YouTube, we're on Facebook, we're on our
00:31:11 --> 00:31:13 own website, spacenutspodcast.com
00:31:14 --> 00:31:16 SpaceNuts IO Either URL will
00:31:16 --> 00:31:19 take you to the same place and have a look
00:31:19 --> 00:31:22 around while you're there. And, Huw in
00:31:22 --> 00:31:24 the studio, he did actually turn up briefly
00:31:24 --> 00:31:26 today, but he forgot to put on his kuiper
00:31:26 --> 00:31:28 belt and his pants fell down, so he had to
00:31:28 --> 00:31:31 make a run for it from me, Andrew
00:31:31 --> 00:31:34 Dunkley. Oh, it's terrible. Thanks, for your
00:31:34 --> 00:31:36 company. We'll see you on the next episode of
00:31:36 --> 00:31:36 Space Nuts.
00:31:36 --> 00:31:37 Professor Fred Watson: Bye. Bye.
00:31:38 --> 00:31:40 Voice Over Guy: You've been listening to the Space Nuts
00:31:40 --> 00:31:43 podcast, available at
00:31:43 --> 00:31:45 Apple Podcasts, Spotify,
00:31:45 --> 00:31:48 iHeartRadio or your favourite podcast
00:31:48 --> 00:31:50 player. You can also stream on
00:31:50 --> 00:31:53 demand at bitesz.com This has been another
00:31:53 --> 00:31:55 quality podcast production from
00:31:55 --> 00:31:56 bitesz.com