Latest / Space Nuts: Astronomy Insights & Cosmic Discoveries / SpaceX Hit the Moon, and the Real Problem Is Just Beginning

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SpaceX Hit the Moon, and the Real Problem Is Just Beginning · Space Nuts: Astronomy Insights & Cosmic Discoveries

• 0:00
  Jonti Horner: Hi there.
• 0:00
  Andrew Dunkley: Thanks for joining us. My name is Andrew
• 0:02
  Dunkley. This is Space Nuts, uh, where we
• 0:05
  talk astronomy and space science. And coming
• 0:08
  up on Today's programme, uh, SpaceX
• 0:11
  in the news, you could say
• 0:14
  for all the wrong reasons, but, um, that's
• 0:16
  debatable, depending on which part of this
• 0:18
  storey that, um, you're talking about. But,
• 0:21
  uh, they've hit the moon. Uh, not in a good
• 0:24
  way. Uh, we'll also be looking at the
• 0:26
  upcoming launch of the Nancy Grace
• 0:29
  Roman Observatory. Uh, we've received a lot
• 0:32
  of questions from the audience about that,
• 0:33
  uh, in recent times and with good reason.
• 0:36
  It's a very exciting mission indeed and
• 0:39
  if time allows us, we'll, uh, look into a new
• 0:41
  study about Neptune's moons. Stick with
• 0:44
  us. That's all coming up on this edition of
• 0:47
  Space Nuts. 15 seconds.
• 0:49
  Jonti Horner: Guidance is internal. 10,
• 0:51
  9.
• 0:53
  Andrew Dunkley: Ignition sequence start.
• 0:54
  Jonti Horner: Space Nuts. 5, 4, 3, 2.
• 0:57
  Andrew Dunkley: 1, 2, 3, 4, 5, 5, 4, 3, 2,
• 1:00
  1. Space Nuts astronauts report at
• 1:03
  Beale. And joining us to, uh, furnish us
• 1:06
  with all his knowledge, which will only take
• 1:08
  a couple of minutes. No, no, it's not. It'll
• 1:10
  take probably a lot longer than that is
• 1:12
  Professor Jonty Horner, professor of
• 1:14
  Astrophysics at the University of Southern
• 1:16
  Queensland. Jonty, hello.
• 1:18
  Jonti Horner: Good afternoon. How are you going?
• 1:19
  Andrew Dunkley: Uh, good. You should feel good too, because
• 1:22
  it's only when I get to like people that I
• 1:24
  insult them like that.
• 1:25
  Jonti Horner: It's fine. It's just like growing up in
• 1:27
  Yorkshire again. It seems to be a
• 1:30
  recurring theme with kind of the better parts
• 1:31
  of the world is that the more you get on with
• 1:33
  people, the more offensively you critic. And,
• 1:36
  you know, the
• 1:39
  inverse of that being that the less you like
• 1:41
  people, the more polite you get. Which
• 1:42
  reminds me of Pratchett's almost version of
• 1:45
  the Montagues and Capulets with the old
• 1:48
  warring aristocracy who'd now got to such a
• 1:51
  level of dissatisfaction with one another
• 1:53
  that the only polite forms of conversation
• 1:55
  were about the weather. And that was it. So
• 1:56
  they have these meetings at formal events.
• 1:58
  It's like, oh, the weather today is
• 2:00
  beautiful, isn't it? M well, you know. Oh,
• 2:02
  yes, yes, but you're not.
• 2:04
  Andrew Dunkley: Yes, that kind of thing. M. Uh,
• 2:07
  we've got a lot to get through and, uh, very
• 2:09
  little time to do it, but we will manage as
• 2:11
  best we can.
• 2:12
  And this, uh, first storey is a bit of a
• 2:14
  combo. Two lunar based
• 2:17
  storeys and depending on where you sit
• 2:20
  on the spectrum of should we or should we
• 2:22
  not, um, they could both be considered bad or
• 2:25
  one could be sort of considered Good.
• 2:28
  Depending on. Yeah, perspective. But,
• 2:31
  uh, it's involving SpaceX and, uh, the
• 2:34
  recent collision, if you want to call it
• 2:36
  that, between a SpaceX rocket body and
• 2:39
  the lunar surface, uh, which,
• 2:42
  uh, happened not so long ago.
• 2:44
  Jonti Horner: Absolutely. I mean, as we're recording this,
• 2:45
  it was very, very recent. Very, very.
• 2:47
  Listening to this, it's slightly in the
• 2:50
  future. And for that reason we didn't talk
• 2:51
  about this last time, because last time we
• 2:53
  were recording in advance of this happening,
• 2:55
  but the broadcast would have gone out after
• 2:57
  it happened, which would have been very
• 2:58
  bizarre. Now we're recording after the
• 3:01
  event and you're hearing after the event, so
• 3:02
  at least the time flow is in an appropriate
• 3:05
  order.
• 3:06
  The storey here is basically
• 3:09
  one of celestial littering, which is a
• 3:11
  recurring theme. We've got this ongoing
• 3:14
  discussion in the past of what goes up, must
• 3:17
  come down, and the ongoing issue
• 3:19
  with the commercialization of space leading
• 3:22
  to a lot of things being launched. And the
• 3:24
  vast majority of those things that are
• 3:26
  launched return to Earth in a fiery blaze of
• 3:29
  glory. We see space junk more and more often
• 3:31
  in our skies, but on Earth,
• 3:34
  the concerns are primarily about the
• 3:36
  atmosphere with the stuff coming back. And
• 3:37
  we've talked a lot in the past about the
• 3:39
  worries atmospheric scientists have about
• 3:42
  dumping all these metals into the upper
• 3:43
  atmosphere and what it'll mean. But very
• 3:46
  rarely do pieces of space junk make it to the
• 3:49
  Earth's surface. And, um, that's because
• 3:51
  we've got an atmosphere. The atmosphere is
• 3:52
  brilliant and protects the surface of the
• 3:54
  Earth from all but the biggest bits of space
• 3:56
  junk. Making it down to Earth.
• 3:58
  Andrew Dunkley: Yep.
• 3:59
  Jonti Horner: Despite that, there is enough concern that
• 4:01
  people are, ah, doing things like calculating
• 4:03
  the odds for insurance companies of how
• 4:05
  likely it is that someone on Earth will die
• 4:07
  due to space junkie in the next decade,
• 4:09
  things like this. So it's not a null
• 4:12
  concern for people on the surface of Earth,
• 4:14
  but the odds of something crashing into
• 4:16
  Earth's surface, that is something we put up
• 4:18
  into orbit, are usually fairly low because
• 4:20
  most of it goes away in the atmosphere,
• 4:23
  ablates. It doesn't burn up. I'm always
• 4:25
  cautious of using the phrasing burn up
• 4:27
  because that evokes fire and fire requires
• 4:30
  oxygen and it's a chemical reaction. This is
• 4:32
  ablation because the air gets superheated and
• 4:34
  bakes away the material. But effectively,
• 4:37
  colloquially, you'd say this all burns up.
• 4:40
  The Earth, though, isn't the only thing out
• 4:43
  there that's in the firing line and this
• 4:46
  is where this storey comes in. So a while
• 4:48
  back, SpaceX launched a couple of
• 4:51
  things to head to the Moon. And in order
• 4:53
  to do that, they had to boost their rocket to
• 4:55
  a higher speed than they normally would do,
• 4:57
  which meant that the upper stage of this
• 4:59
  rocket went onto a very elongated orbit
• 5:01
  around the Earth, uh uh, and then essentially
• 5:03
  goes into free fall. It has burned all its
• 5:06
  fuel. It is, to all intents and purposes, out
• 5:08
  of control. And that means its orbit just
• 5:10
  evolves under the gravity of the Earth and
• 5:12
  the Moon and the vagaries of the environment
• 5:15
  around the Earth. Fast forward to
• 5:18
  now and that out of control rocket body
• 5:20
  crashed into the Moon. Now, the final
• 5:24
  collision was predicted in advance. This was
• 5:27
  big news for at least a week beforehand,
• 5:30
  and it was estimated roughly where the thing
• 5:32
  would hit the Moon. Now you're talking hit
• 5:34
  about a fairly hefty chunk of material.
• 5:36
  You're talking about, you know, a couple of
• 5:39
  thousand kilos, if not more, a fairly big
• 5:42
  chunk of material crashing into the Moon's
• 5:45
  surface at a speed of a few kilometres per
• 5:48
  second. And so the predictions were that
• 5:51
  when this hit in the location it hit,
• 5:53
  it would dig out a crater maybe 20, 25 metres
• 5:56
  across, and kick a load of dust and material
• 5:59
  up. It will create a plume that would rise
• 6:01
  above the Moon's limb, probably rise as high
• 6:03
  as 100 kilometres or so, and slowly fall back
• 6:05
  to the surf of the Moon.
• 6:08
  The time at which impact was going to happen
• 6:10
  was predicted, so astronomers on the part of
• 6:13
  the Earth that could see the Moon were
• 6:14
  watching to see what happened. Albert,
• 6:17
  to be fair, it was predicted that for most
• 6:19
  people you would see absolutely nothing. This
• 6:21
  thing was going to hit on the daylight side
• 6:22
  of the Moon and so reflected sunlight would
• 6:25
  obscure pretty much everything.
• 6:28
  So people looked, didn't really see anything.
• 6:31
  The only really, I think,
• 6:34
  strong indication that something was seen
• 6:36
  from the ground were a group of people
• 6:38
  observing from the Lowell Observatory in the
• 6:40
  US who were looking
• 6:43
  specifically at very specific wavelengths of
• 6:46
  light for sodium ions and lithium ions.
• 6:49
  And they saw what appeared to be an impact
• 6:51
  plume at the right location at the right
• 6:54
  time, kind of confirming that the impact
• 6:56
  happened.
• 6:57
  Andrew Dunkley: Yeah.
• 6:58
  Jonti Horner: Then after the event, the first images came
• 7:00
  back of the site that was hit. And those
• 7:02
  images came back from a Korean
• 7:05
  spacecraft, um, South Korea's first ever
• 7:08
  lunar spacecraft, that was launched back in
• 7:10
  2022, actually in August
• 7:12
  2022 has been floating around, minding its
• 7:15
  own business, doing work and pretty much
• 7:17
  widely being forgotten. I don't remember ever
• 7:19
  talking about this spacecraft before, even
• 7:20
  though me. It's a great. Yeah, even though
• 7:23
  it's a great achievement that the Koreans got
• 7:25
  it into lunar orbit and have been doing great
• 7:26
  stuff with it.
• 7:27
  Andrew Dunkley: Yeah.
• 7:27
  Jonti Horner: But this spacecraft, Dunuri, flew
• 7:30
  repeatedly over the area where the impact was
• 7:33
  going. And the
• 7:35
  Korean, um, Aerospace Research Institute
• 7:38
  Carri released an announcement that said,
• 7:41
  and I'm quoting here, Dhanuri began
• 7:44
  observations about 30 minutes before the
• 7:45
  collision and um, through orbit control
• 7:48
  passed over the impact site multiple times,
• 7:50
  conducting a total of eight imaging
• 7:52
  sessions. Through this observation, changes
• 7:55
  in the terrain around the impact site and
• 7:57
  traces of ejecta spread were confirmed. The
• 8:00
  spacecraft secured both pre collision and
• 8:02
  immediate post collision footage, enabling
• 8:04
  analysis of the changes. Changes, uh, that
• 8:06
  have happened. So there are now images only
• 8:08
  looks like a little black smudge, but to be
• 8:10
  fair, this is an area maybe 20 or 25 metres
• 8:13
  across. It's pretty impressive that we can
• 8:15
  get images that resolve that impact feature
• 8:18
  on the surface of the moon. And I think that
• 8:21
  in itself is going to be pretty important
• 8:24
  for researchers studying how craters form,
• 8:26
  how the lunar impact kind of scenarios
• 8:29
  happen. When you're hitting an object with
• 8:31
  the regolith, like the moon without an
• 8:34
  atmosphere to protect it, all this kind of
• 8:36
  stuff's pretty important. But it's doubly
• 8:38
  important in the context of our future use of
• 8:40
  the moon. You know, NASA have got these plans
• 8:42
  to put astronauts in a permanent lunar base
• 8:44
  at the South Pole. I know China have
• 8:46
  expressed similar aspirations. Elon Musk is
• 8:49
  looking at building a lunar industry, which
• 8:51
  we'll come to in a minute. Yeah. Ah, if
• 8:54
  you're wanting to have permanent presence on
• 8:56
  the moon, and particularly permanent human
• 8:57
  presence, you need to have a fairly good
• 9:00
  understanding of what's going to happen when
• 9:01
  impacts happen. You would have also thought
• 9:04
  though that you'd like to prevent impacts
• 9:06
  from happening, particularly impacts from
• 9:07
  things that are out of control. Because if
• 9:09
  this thing had come into the Earth's
• 9:10
  atmosphere, pretty much all of it would have
• 9:13
  ablated. You wouldn't have had to worry on
• 9:15
  the ground. On the Moon though,
• 9:18
  it makes it to the surface intact. That
• 9:21
  size of that impact scar, 25, 27 metres
• 9:24
  across, sounds to me very much like the size
• 9:27
  of a lunar habitat that you'd build. And the
• 9:29
  last thing I would want is to send astronauts
• 9:31
  up to the moon and then have a bit of a
• 9:33
  discarded rocket crash in and wipe out the
• 9:36
  habitat and kill them. Doesn't sound like a
• 9:38
  good idea. Not just that it's raised
• 9:41
  concerns not only about our kind of future
• 9:43
  presence on the moon, but about the
• 9:44
  preservation of our archaeological sites on
• 9:46
  the moon. We've talked about the incredible
• 9:49
  work of Professor Alice Gorman in Adelaide,
• 9:51
  who talks about space archaeology and has
• 9:54
  Been trying to raise awareness of the
• 9:56
  cultural impact of places like the Apollo 11
• 9:58
  landing site, where we've got this pristine
• 10:00
  record of humanity's first steps on the moon.
• 10:03
  And it'd be tragic if something like this
• 10:05
  happened and crashed into that. Yeah, it's
• 10:07
  really caused a lot of discussion about
• 10:10
  what's going on, what we should do about it.
• 10:13
  And I don't know that it's a particularly
• 10:15
  good look for SpaceX that this has happened,
• 10:17
  but it should be stressed that they are far,
• 10:18
  uh, from alone. I saw listed on a
• 10:21
  BBC article at the time of the
• 10:24
  impact detailed some of the other things that
• 10:26
  have hit the moon and they reckon that
• 10:30
  more than 3,000 human made objects have
• 10:33
  now either landed on or impacted the moon.
• 10:35
  Andrew Dunkley: Really? 3,000?
• 10:36
  Jonti Horner: 3,000 or more.
• 10:38
  Andrew Dunkley: I would never have guessed that many.
• 10:40
  Jonti Horner: It's astonishing. And that's a total of more
• 10:42
  than 190 tonnes of material. Now
• 10:45
  some of that landed softly. You know, we
• 10:47
  talked about Apollo 11 for example. The lunar
• 10:49
  landers from many nations, many nations have
• 10:52
  now landed on the moon. We've got crash
• 10:54
  landings like the Israeli mission that
• 10:56
  spattered tardigrades across the moon because
• 10:58
  they could. Which still strikes me as one of
• 11:00
  the dumbest space missions ever carried out.
• 11:03
  You know, from an astrobiology point of view,
• 11:05
  we want to go to places and look for evidence
• 11:06
  of life. The last thing you want to do is
• 11:08
  smear it over the face of the moon. Hey look,
• 11:10
  we've put life there anyway. That's an
• 11:12
  entirely other topic. But there's this long
• 11:14
  history of things hitting the moon in a both
• 11:17
  controlled and uncontrolled fashion. And it's
• 11:19
  going to happen more and more the more we put
• 11:21
  stuff out there.
• 11:22
  Andrew Dunkley: Yep.
• 11:23
  Jonti Horner: So it's caused a lot of discussion. It is
• 11:26
  really, really interesting. But it does shine
• 11:29
  a light on the risk for future missions more
• 11:31
  than anything else.
• 11:32
  Andrew Dunkley: Yeah, it does. Um,
• 11:34
  notwithstanding that, there is,
• 11:37
  um, an international law in place that you're
• 11:40
  responsible for cleaning up your own mess.
• 11:42
  But, um, when things get out of control
• 11:45
  or fly off in directions that make them
• 11:47
  irretrievable, what can you do
• 11:50
  about it?
• 11:51
  Jonti Horner: Absolutely. And I would be very interested to
• 11:54
  see whether any applications of that law
• 11:57
  apply to things beyond the Earth's
• 11:59
  atmosphere, because that
• 12:01
  gets enforced when you look at people
• 12:04
  cleaning up things on Earth. So there was a
• 12:06
  storey a few years ago about some SpaceX
• 12:09
  rocket parts, um, in the snowy
• 12:12
  mountains in Australia and SpaceX in theory
• 12:14
  had to come and collect them and there was a
• 12:17
  little bit of a lag in that happening.
• 12:19
  Similarly, when There was a fragmentation of
• 12:20
  one of their big starship test launchers that
• 12:23
  uh, dropped debris around the Caribbean.
• 12:25
  There was a lot of controversy about whether
• 12:27
  they were actually bothering to collect stuff
• 12:28
  or not.
• 12:29
  Andrew Dunkley: There is a faster way. It's called ebay.
• 12:32
  Jonti Horner: Oh absolutely.
• 12:36
  This is kind of an ongoing thing and I'm not
• 12:38
  sure that once again legislation has kept
• 12:41
  up with our use. We were talking about this
• 12:44
  last week with satellites I think, and with
• 12:46
  the FAA and FCC approving things but making
• 12:49
  it very clear that they weren't there to
• 12:51
  judge on whether the use of space was
• 12:53
  sensible. They were just ruling on their
• 12:54
  small area of influence and abrogating other
• 12:57
  responsibility.
• 12:58
  I don't think we have yet any real
• 13:01
  global pathway to improving things and
• 13:04
  getting a better handle on what we should and
• 13:06
  shouldn't do. But the discussions are
• 13:08
  happening and every time something like this
• 13:10
  comes along it further prompts those
• 13:12
  discussions and raises awareness of the
• 13:14
  problem, I guess.
• 13:15
  Andrew Dunkley: Yes. And uh, once people are
• 13:18
  up there in a permanent or semi permanent
• 13:20
  situation, that's when you've really
• 13:23
  got to start thinking about these kinds of
• 13:25
  problems. Hitting the moon at the moment is
• 13:27
  um, it is a risk for
• 13:30
  existing infrastructure and historical sites.
• 13:33
  But the day will come where people are there
• 13:35
  and that creates a whole new ball game. So.
• 13:38
  Jonti Horner: And industry will be there. Which brings us
• 13:40
  to the second half of this storey.
• 13:42
  Andrew Dunkley: Well, let's, let's get into that because this
• 13:44
  also involves SpaceX and
• 13:47
  Elon's big plan is to put a,
• 13:50
  um, uh, manufacturing plant on
• 13:53
  the moon to build uh, his
• 13:55
  starmind AI satellite array.
• 13:59
  Uh, and it looks like that this will be a
• 14:02
  fully automated system. They'll manufacture
• 14:04
  these things and launch them from the moon.
• 14:07
  And we're talking like, I don't
• 14:10
  know, M. Is it a million of these things?
• 14:12
  Jonti Horner: That's what it wants to do.
• 14:14
  Andrew Dunkley: Yeah, that's. I mean this is the stuff of
• 14:16
  science fiction, but it's rapidly becoming
• 14:19
  something real, isn't it?
• 14:21
  Jonti Horner: It is. And I mean we've discussed the light
• 14:23
  pollution side of this repeatedly on the
• 14:25
  show, both myself and Fred Watson. This
• 14:28
  StarMind idea is the idea that
• 14:31
  they will launch essentially data centres and
• 14:34
  AI centres into Earth orbit to farm
• 14:36
  solar energy and you'll have these
• 14:40
  heavily computing based satellites with
• 14:42
  enormous solar panels probably at a
• 14:45
  relatively high altitude above the Earth so
• 14:47
  that they can get permanent sunshine, which I
• 14:50
  know a number of reports over the last few
• 14:51
  months since this has talked about have
• 14:54
  spoken about how this will give a visible
• 14:56
  ring in the night sky that'll be visible
• 14:58
  all night from all locations on the Earth.
• 15:01
  And it'll be like living with a
• 15:03
  narrow, very thin ring, a bit like Saturn's
• 15:06
  rings, but just a single ring rather than
• 15:08
  really broad one. Lots of concern,
• 15:11
  lots of speculation about that. This
• 15:14
  storey relates to one of the
• 15:17
  quarterly calls that
• 15:19
  SpaceX are having. This is apparently the
• 15:21
  first ever, but they're going to happen every
• 15:23
  quarter and it's probably something that's
• 15:25
  followed on from the listing of SpaceX on the
• 15:27
  stock exchange and that where
• 15:30
  Musk talks to the investors. And um, this
• 15:33
  call was on the 4th of August, just under a
• 15:35
  week ago for me, but by the time you hear
• 15:37
  this three weeks ago. And in
• 15:40
  that call, Musk talked widely about
• 15:43
  his dreams to put factories on the
• 15:46
  moon. This is something he's talked about
• 15:47
  before, so it's not utterly new, but he's
• 15:50
  given more detail of what they want. He
• 15:52
  talks about landing a huge amount of tonnage
• 15:54
  on the moon to build factories. The factories
• 15:57
  will use robots akin to the Optimus robots
• 16:00
  that they use in the, um, Tesla car
• 16:02
  manufacturers, I think. And he's already
• 16:04
  talking about sending some of those Optimus
• 16:06
  robots to Mars. He wants to use
• 16:09
  the moon to build these starmind
• 16:12
  AI satellites which he'll then launch with
• 16:14
  giant rail guns using the obs abundant solar
• 16:17
  power you can generate on the moon, building
• 16:19
  a really, really, really long track with a
• 16:21
  kink at the end where you can accelerate
• 16:24
  using magnets, something to launch
• 16:27
  speed. And this is again something that's
• 16:28
  featured heavily in science fiction over the
• 16:30
  years as a method for launching things from
• 16:33
  bodies without an atmosphere. All makes
• 16:35
  sense, but the idea he's got is
• 16:38
  that, uh, by going onto the moon, he can
• 16:41
  scale up manufacturing to get to being a
• 16:44
  factor of a thousand and a factor of
• 16:47
  a million times more than he has on Earth.
• 16:50
  So a huge, vast expansion in their
• 16:53
  building capacity. And it's a kind
• 16:56
  of thing that, huh, many people might poo
• 16:59
  poo, but I think if we were talking a decade
• 17:00
  ago, people would have been poo pooing the
• 17:02
  idea of Starlink. And he's been very
• 17:04
  successful getting that off the ground and up
• 17:06
  and running. So I wouldn't rule this out. And
• 17:09
  long term we are seeing the dawn
• 17:11
  of the commercial use of space and the
• 17:13
  commercial exploitation of the moon and
• 17:15
  asteroids is sure to follow. So it wouldn't
• 17:18
  surprise me if other companies are having
• 17:19
  similar ideas and it may maybe that SpaceX
• 17:22
  are the first but not the only ones to do
• 17:24
  this if it happens. What I
• 17:27
  found interesting about this is this storey's
• 17:30
  going round at exactly the same time that
• 17:32
  we're talking about the uncontrolled crash of
• 17:34
  the SpaceX rocket to the moon. Which means
• 17:37
  you've got this almost a conflict of interest
• 17:40
  for SpaceX here because on the one hand
• 17:43
  they want to be able to launch their rockets.
• 17:45
  They've got to get that tonnage into space,
• 17:46
  as Musk says. And if they're launching things
• 17:48
  to the moon, that'll leave a lot of rocket
• 17:51
  bodies on orbits that could event actually
• 17:52
  impact the moon and they're out of control.
• 17:55
  Yet at the same time he's looking at building
• 17:57
  capacity for manufacturing on the surface of
• 18:00
  the moon. Now that strikes me that on the
• 18:03
  one hand he's increasing the risk that his
• 18:06
  industry will be damaged by his own industry,
• 18:08
  if that makes sense. Oh yeah, there's always
• 18:10
  a possibility that one of his rockets will
• 18:12
  crash into one of his factories. So it may
• 18:14
  well be that that leads to a certain amount
• 18:17
  of self interest in looking at ways to manage
• 18:19
  it that the outcry of astronomers wouldn't.
• 18:22
  It's a lot more impelling for
• 18:25
  a company like SpaceX to want to find a
• 18:27
  solution to a problem that will directly
• 18:29
  impact them than a problem that's just
• 18:32
  upsetting a few people and is considered a
• 18:33
  little niche. So it's going to be really
• 18:35
  interesting to see how these two things kind
• 18:37
  of develop in parallel, I think.
• 18:39
  Andrew Dunkley: Yeah. Uh, Elon Musk is um,
• 18:42
  to some a visionary, to others an absolute
• 18:45
  nutter. But uh, when you look at what he's
• 18:48
  achieved, you can't deny it. And when he
• 18:50
  starts to talk about doing things like this,
• 18:53
  you can't say it won't happen because
• 18:57
  he's proven that he'll put his money where
• 18:59
  his mouth is over and over again.
• 19:01
  Jonti Horner: Yeah. Um, and I do try when I'm talking about
• 19:03
  this, I know I fail sometimes, but I try to
• 19:05
  be as evenhanded as I can be M because I
• 19:07
  think very few people are purely good or
• 19:10
  purely evil. There's good and bad to most
• 19:11
  people and there are good and bad to the
• 19:13
  things that people do. And when we've talked
• 19:15
  a lot about Starlink, I always want
• 19:18
  to be a parent of stress that there is real
• 19:20
  benefit comes from this as well. Cause I
• 19:21
  think a big mistake people make is only
• 19:23
  focusing on the negative. And that doesn't
• 19:26
  put you in a good position. You need to look
• 19:28
  not to stop things entirely, but to look for
• 19:30
  a position where you get the maximum benefit
• 19:32
  for the minimum cost. You know that sweet
• 19:33
  spot.
• 19:34
  Andrew Dunkley: Yeah.
• 19:34
  Jonti Horner: And it is undeniable that Starlink has
• 19:37
  brought with it great benefits to people
• 19:40
  in terms of being able to access the Internet
• 19:42
  and access communication where previously
• 19:44
  they weren't able to see, were too remote.
• 19:46
  It's also come with associated problems and I
• 19:48
  think this kind of endeavour is going to be
• 19:51
  the same. It's also probably very fair to say
• 19:54
  that that commercial use of the Moon and
• 19:56
  commercial use of other things in the solar
• 19:58
  system is going to happen whether SpaceX do
• 20:00
  it or not. But they're very much at the
• 20:02
  forefront. So I don't see an argument to be
• 20:05
  made for just saying, oh well, they should
• 20:06
  stop this and think about it. I think what's
• 20:08
  really important is all this stuff is
• 20:10
  discussed very publicly and, um,
• 20:13
  we figure out what humanity as a
• 20:16
  whole thinks is the right balance to have.
• 20:19
  And that's challenging. I mean, it's not a
• 20:21
  case of nothing and it's not a case of
• 20:23
  everything. But it's probably going to be the
• 20:25
  case that, uh, the use of the Moon is just
• 20:28
  like the use of low Earth orbit, where the
• 20:30
  commercial use rapidly outstrips our,
• 20:32
  uh, abilities, at least at first, to
• 20:34
  legislate around it and then the legislation
• 20:36
  will come afterwards in much the same way. We
• 20:39
  were talking last week about previous
• 20:41
  examples being things like the Internet or
• 20:43
  even the printing press, things like this.
• 20:45
  The use always outstrips the legislation.
• 20:48
  Then the legislation sprints capture.
• 20:51
  Andrew Dunkley: Yes, uh, well, it crawls
• 20:54
  in some cases, but I know what you mean. Um,
• 20:57
  and look, if SpaceX don't do this, as you
• 20:59
  said, someone else will. It's, um, you know,
• 21:02
  everyone can point the finger at Elon Musk
• 21:04
  and SpaceX and say, oh, naughty. But
• 21:07
  if they say, look, yeah, okay, we agree
• 21:10
  it's a bad idea, we won't do it, someone else
• 21:12
  will. Absolutely, most certainly.
• 21:15
  So, uh, it's probably more a case of finding
• 21:18
  a way to manage this properly into the future
• 21:21
  rather than just saying, no, it shouldn't
• 21:23
  happen, shouldn't be done, no way, no how,
• 21:26
  because it will happen regardless.
• 21:29
  Interesting times ahead. Uh, yeah, a couple
• 21:31
  of interesting storeys focused, uh, on the
• 21:34
  Moon. And if you want to read about that
• 21:35
  impact, you can do that at,
• 21:38
  uh, the
• 21:40
  space.com website. I knew I'd find it there
• 21:43
  somewhere. This is Space Nuts with Andrew
• 21:45
  Dunkley and Professor Jonty Horner.
• 21:49
  I believe that this nation should commit
• 21:51
  itself to achieving the goal,
• 21:54
  before this decade is out, of landing a
• 21:57
  man
• 21:57
  Jonti Horner: on the moon and returning him safely to the
• 21:59
  Earth. These nuts.
• 22:02
  Andrew Dunkley: Now to something very exciting. We've been
• 22:04
  building up to this for quite some time and
• 22:07
  as this podcast, uh, goes
• 22:09
  out um, the day of release for this one is
• 22:12
  the 27th of August. Uh, we are three
• 22:15
  days away from the launch
• 22:18
  of the Nancy Grey Space Roman
• 22:20
  Observatory. That is big time
• 22:23
  excitement.
• 22:24
  Jonti Horner: It is of course the caveat is that uh, in the
• 22:26
  couple of weeks between recording this and it
• 22:28
  going live, it could be delayed change, you
• 22:30
  know, it's like, like the trains in the uk,
• 22:32
  never trust that they're going to arrive
• 22:34
  until they actually have done and even then
• 22:35
  be sceptical. Yeah, it's that kind of
• 22:38
  thing. But in this case that would be quite
• 22:41
  startling because until very recently
• 22:44
  everybody was expecting this telescope to be
• 22:45
  launched next year. So the, the launch,
• 22:48
  if it goes ahead on 30 August
• 22:51
  will be a launch that is nine months ahead of
• 22:53
  schedule, which is very, very cool. Now the
• 22:55
  scheduled launch time at the time of
• 22:58
  recording will be the 30th of August at
• 23:00
  uh, 9:26pm Australian
• 23:03
  Eastern Standard Time, which is 11, um,
• 23:05
  26:00am Universal Time or Greenwich Mean
• 23:08
  Time. I think a lot of these launches get
• 23:11
  streamed online so for those of you who are
• 23:13
  keen, there will almost certainly be live
• 23:15
  coverage of that. Uh, and a lot of very
• 23:17
  nervous people watching the launch hoping
• 23:18
  that it doesn't turn into a. Which has
• 23:21
  happened before.
• 23:22
  Andrew Dunkley: It has. We don't want to think about
• 23:25
  that. We're talking $4 billion
• 23:28
  worth of hardware.
• 23:29
  Jonti Horner: We are. But I mean this is why there are
• 23:31
  insurance policies, right? It's um,
• 23:35
  there is a risk.
• 23:36
  Andrew Dunkley: I'm surprised you'd find an insurance company
• 23:38
  willing.
• 23:40
  Jonti Horner: I think it's become fairly big business
• 23:41
  actually. I mean it's not my area, but I
• 23:43
  remember when we went to meetings
• 23:46
  a few years ago about off Earth resource
• 23:49
  collection, there was discussion about
• 23:50
  insurance and stuff like that and apparently
• 23:53
  there are insurance underwriters who insure
• 23:55
  satellites and launchers and
• 23:58
  I think I seem to remember, although I stand
• 24:00
  to be corrected on this, that the cluster
• 24:02
  mission probably 15, 20 years ago
• 24:05
  now blew up on the launch pad and insurance
• 24:07
  allowed them to essentially rebuild it and
• 24:10
  launch it again. Um, so it does happen, but
• 24:13
  fingers crossed, touch wood, there will be no
• 24:16
  problems with this. And um, what will happen
• 24:17
  is that on the 30th of August a uh, rocket
• 24:20
  will take off. SpaceX rocket that will carry
• 24:23
  Nancy Grace Roman Telescope
• 24:25
  into Earth orbit and beyond will boost
• 24:28
  hard, um, just like happened with the James
• 24:30
  Webb Space Telescope to give it a good kick
• 24:32
  because this thing is destined to go out to
• 24:34
  join James Webb at the outer Lagrange point,
• 24:37
  um, beyond the Earth, uh, so about a million
• 24:39
  kilometres further from the sun than the
• 24:41
  Earth is but moving in lockstep with our ah,
• 24:43
  at this kind of gravitational sweet spot
• 24:45
  where you can hang around fairly safely for a
• 24:48
  long time. To do that it is
• 24:50
  loaded with what is described as a very
• 24:53
  toxic fuel, um, hydrazine.
• 24:57
  They want to move away from it but until they
• 24:59
  find a better alternative they haven't yet.
• 25:00
  So as we talk right now
• 25:03
  the spacecraft has been fully fueled
• 25:06
  which is why they're fairly confident that
• 25:08
  they'll launch on time. That amount of fuel
• 25:11
  sets the lifetime of the mission. And there
• 25:14
  were similar discussions with Jim James Webb
• 25:15
  when it launched a few years ago in that the
• 25:18
  nominal mission is five years. So once Nancy
• 25:21
  Grace Roman gets to the L2 point and that
• 25:23
  journey will take about 100 days from the
• 25:25
  launch it is scheduled to have
• 25:28
  around a five year mission.
• 25:31
  May have a longer mission than that if it
• 25:34
  manages to keep hold of its hydrozine fuel.
• 25:37
  So what happened with James Webb was uh,
• 25:39
  everybody was delighted with how accurately
• 25:41
  and beautifully it launched so it needed to
• 25:43
  use less fuel to get on station which meant
• 25:46
  that have more fuel for a longer life
• 25:49
  and therefore the projected mission went from
• 25:52
  five years to maybe 10 or 20. Managed to keep
• 25:55
  those sorts of fuel and hopefully fingers
• 25:57
  crossed, such wood. Again the same will be
• 26:00
  true for Nancy Grace Roman Telescope.
• 26:03
  People have been really looking forward to
• 26:04
  this. Now the first I remember of Nancy Grace
• 26:07
  Roman Telescope was when it used to be badged
• 26:09
  as wfirst a Wide Field Infrared Survey
• 26:11
  Telescope. That was kind of the first
• 26:13
  proposal and that was going back to 2011,
• 26:15
  2012. And shortly after those first
• 26:18
  proposals there was a really interesting
• 26:21
  storey came out that NASA had been told
• 26:24
  that there were suddenly a number of
• 26:27
  what are known as National Reconnaissance
• 26:29
  Office telescopes made m by the Harris
• 26:31
  Corporation. Um, the nro
• 26:34
  uh, offered to donate two telescopes to
• 26:37
  NASA which are telescopes comparable in
• 26:40
  size to the Hubble Space Telescope but a
• 26:41
  wider field of view. To put that in other
• 26:44
  language. Effectively the defence community
• 26:46
  in the US said by the way, we've got a couple
• 26:48
  of spy satellites that we're not going to use
• 26:50
  so do you want them to actually do science?
• 26:53
  Which meant at least to me for the first time
• 26:56
  I became aware of the fact that there were a
• 26:57
  number of Hubble class telescopes orbiting
• 26:59
  the Earth. Looking down, um, I hadn't quite
• 27:02
  realised spy satellites had got that big and
• 27:04
  that impressive. But anyway
• 27:07
  that was a really nice
• 27:09
  mechanism through which you know you could do
• 27:12
  a cool mission a little bit cheaper. That
• 27:15
  got a bit of political interest and all the
• 27:16
  rest of it. But over time since
• 27:19
  the telescope was planned and then approved
• 27:22
  and then built. Now, I must confess
• 27:25
  that I don't actually know whether the
• 27:27
  current iteration of Nancy Grace Roman is a
• 27:29
  former spy satellite or whether they moved
• 27:31
  away from that. But what it is going to be is
• 27:34
  a space telescope with a mirror 2.4 metres
• 27:37
  across, which is your Hubble Space Telescope
• 27:39
  size, wider field of view than Hubble
• 27:42
  that will observe in the optical and in the
• 27:45
  near infrared using two instruments. So it's
• 27:48
  going to have a very wonderful wide field
• 27:50
  camera. This is a camera with
• 27:53
  300 megapixels. So
• 27:56
  that's a hell of a lot better than the CCD
• 27:58
  camera I've got on my digital telescope here.
• 28:01
  On my telescope here. Fabulous camera
• 28:04
  that will work at both visible and near
• 28:06
  infrared, will be able to take take images in
• 28:08
  a wide variety of colour bands and things
• 28:10
  like this. So that's going to be a fabulous
• 28:13
  camera that allows survey work to be done.
• 28:15
  And a lot of the work that is planned for
• 28:18
  this incredible telescope will be looking at
• 28:21
  the kind of cosmology stuff that you get so
• 28:22
  many questions about dark energy and
• 28:25
  gravitational lensing and things like this.
• 28:27
  Stuff that's a bit outside my professional
• 28:29
  wheelhouse, but it's also going to be
• 28:32
  carrying out an incredible survey looking for
• 28:34
  exoplanets. It's going to stare at the bulge
• 28:36
  of the Milky Way galaxy, looking for gravity
• 28:39
  gravitational microlensing events, which is
• 28:41
  when a planet going around a star where we
• 28:43
  can see neither the star nor the planet
• 28:46
  passes between us and a more distant star
• 28:48
  and some of the light from that sour is bent
• 28:50
  and focused towards us, causing the star to
• 28:52
  brighten and then fade. That microlensing
• 28:55
  event lets us detect the object that we can't
• 28:57
  see passing by in between and it
• 29:00
  will also let us find free floating planets.
• 29:02
  So Nancy Grace Roman Telescope still going to
• 29:05
  do a fabulous kind of census type survey
• 29:07
  of planets towards the middle of our galaxy
• 29:10
  using this micro technique. It's
• 29:13
  also carrying its other instrument, which is
• 29:15
  a really high contrast camera with a very
• 29:18
  small field of view, very different, that is
• 29:21
  attached to a coronagraph. And a coronagraph
• 29:24
  is a fabulous device that allows you to block
• 29:26
  out the light from a light source like
• 29:29
  a star and allow you to look at things that
• 29:32
  are very near to that light source that would
• 29:34
  normally be lost in the glare. And um, this
• 29:36
  is planned to take advantage of the fact that
• 29:38
  this thing's in space. We don't have the
• 29:40
  Earth's atmosphere to deal with to
• 29:43
  use both the camera and a spectrograph that
• 29:45
  are connected to this coronagraph
• 29:48
  to look at exoplanets and actually try and
• 29:51
  get direct imaging observations of them and
• 29:54
  to learn more about their atmospheres. It'll
• 29:56
  be used for planets more like the size of
• 29:57
  Jupiter than the Earth, but it's going to be
• 30:00
  an incredible tool for learning more about
• 30:02
  planets around stars like the sun
• 30:03
  effectively.
• 30:04
  Andrew Dunkley: Yeah, it's going to be very exciting and uh,
• 30:07
  can't wait. Hopefully everything will run
• 30:09
  according to plan on August 30th, which
• 30:12
  uh, by the time this, this podcast is
• 30:14
  released we'll be three days away. And
• 30:18
  um, yeah, we wait with bated breath. Uh, it's
• 30:21
  only got to go a million kilometres to get
• 30:23
  where it's going which will take um, it's not
• 30:26
  a heck of a long trip but it's going to take
• 30:28
  them ah, a little while to get there. I can't
• 30:31
  remember how long it was now.
• 30:33
  Jonti Horner: Oh well it's 100 days to roll on out to the
• 30:35
  Lagrange point for a start and then it'll be
• 30:37
  time to get yourself fired up and
• 30:40
  get all the testing done and all the rest of
• 30:42
  it. But it's going to be a fabulous tool and
• 30:44
  I think, I know I myself, my
• 30:47
  research is mainly theoretical, I'm mainly
• 30:49
  working on computers and to be honest I'm at
• 30:51
  a stage in my career and I'm sure Fred Watson
• 30:53
  can empathise with this where I'm becoming
• 30:54
  more of an administrator and a supervisor
• 30:56
  than I am a researcher. But um, I know
• 30:58
  colleagues of mine at UNISQ have been very
• 31:00
  successful in getting time to use the James
• 31:03
  Webb Space Telescope to study exoplanet
• 31:05
  atmospheres. And I'm thinking here
• 31:06
  particularly of George Zhao and Chelsea Huang
• 31:09
  who are really uh, truly world class
• 31:11
  scientists and I think they are waiting with
• 31:13
  bated breath to see what be able to do with
• 31:15
  this. So yes, you'll get a lot of discoveries
• 31:18
  coming out from the us but we will have
• 31:20
  Australian involvement looking at this and
• 31:22
  getting amazing results right here in
• 31:24
  Australia and for people living in other
• 31:26
  countries, other countries will have their
• 31:28
  own scientists beavering away
• 31:31
  using Nancy Grey's Roman telescope to do
• 31:33
  amazing, amazing things indeed.
• 31:35
  Andrew Dunkley: And uh, we will uh, obviously let you
• 31:38
  know how it all goes uh, once we know
• 31:42
  whether or not it launched on time, whether
• 31:44
  or not anything fingers crossed happened to
• 31:46
  uh, slow it down, whatever. Hopefully not. It
• 31:49
  should all go according to plan one
• 31:52
  hopes. Um, anyway we'll watch with interest
• 31:55
  and you can read that storey also on
• 31:57
  space.com, but uh, there are plenty of
• 31:59
  platforms carrying the storey of the Nancy
• 32:01
  Grace Roman Observatory. And um,
• 32:03
  if all goes to plan, there'll be many, many
• 32:06
  more storeys in a few days time. This is
• 32:08
  Space Nuts and you're uh, with Andrew Dunkley
• 32:11
  and Professor Jonty Horn.
• 32:16
  Jonti Horner: Three, two, one.
• 32:18
  Space Nuts.
• 32:20
  Andrew Dunkley: And seeing we've got a few minutes up our
• 32:22
  sleeve, we'll go on to our third and final
• 32:24
  storey.
• 32:25
  And this one involves three, uh,
• 32:28
  moons of Neptune which they think,
• 32:30
  according to a new study, might have uh, been
• 32:33
  created in a rather
• 32:36
  um, Earth, uh, shattering or Neptune
• 32:38
  shattering way involving the moon
• 32:41
  Triton, which is also a very mysterious
• 32:43
  place in our solar system.
• 32:46
  Jonti Horner: Yeah, and this is a fascinating one. Now some
• 32:48
  of the coverage of this has been kind of
• 32:50
  presenting this as a new theory that's come
• 32:53
  up from the observations. And to me it's
• 32:54
  actually a bit the other way around where
• 32:57
  these are observations that are potentially
• 32:59
  supporting ideas that have been held for a
• 33:01
  fair while. Now. Neptune has a
• 33:04
  system of satellites like the other giant
• 33:07
  planets in the ice giant Uranus. But
• 33:09
  Neptune's is unusual. You've a
• 33:12
  real behemoth of a moon in the form of Triton
• 33:15
  that along with our moon is one of the two
• 33:18
  oddest moons of any planet in the solar
• 33:20
  system. To give a bit of context from that
• 33:23
  and take a step back, aside from our moon and
• 33:26
  Triton, all of the other hundreds of moons
• 33:29
  in the solar system fall into two real
• 33:31
  categories. You've got regular satellites
• 33:34
  which fall on orbits
• 33:37
  that are above the equators of their planets,
• 33:39
  are very close in and they're going around on
• 33:41
  circular orbits that are in the same
• 33:43
  direction as a planet's spin. And they're
• 33:45
  thought to have formed particularly around
• 33:47
  the gas giant planets, but also around Uranus
• 33:50
  and Neptune in much the same way that the
• 33:52
  planets formed around the sun in that you had
• 33:53
  a disc of material around the planet and
• 33:55
  moons formed in that disc. They're quite
• 33:57
  compact and close in. You've
• 34:00
  then got irregular satellites which are um,
• 34:02
  much, much, much further from their planets,
• 34:05
  um, are found around. The outer planets
• 34:08
  are moving on a wide range of very elongated,
• 34:11
  often retrograde orbits to be captured
• 34:14
  objects that have then been smashed into
• 34:16
  pieces, giving you families of satellites.
• 34:19
  And it's these that give Jupiter and Saturn
• 34:21
  in particular such incredible numbers of
• 34:23
  satellites. More than 100 for Jupiter, more
• 34:26
  than 200 for Saturn, currently known.
• 34:29
  Triton and our moon stand out as
• 34:32
  oddities because they don't quite fit either
• 34:34
  class. And for Earth's
• 34:37
  satellite, the moon, the origin of the moon
• 34:39
  seems to have been a giant impact, very
• 34:41
  different to either scenario. For the Regular
• 34:43
  irregular sate. But Triton around
• 34:46
  Neptune is really kind of weird.
• 34:49
  It's a moon that is 2,700 kilometres in
• 34:51
  diameter. It's a chunky
• 34:54
  boy. It is close enough in that it
• 34:57
  would normally be considered one of the
• 34:59
  regular satellites. And it is orbiting
• 35:01
  pretty much above Neptune's equator. But it's
• 35:04
  going around the wrong way. It's moving on a
• 35:06
  retrograde orbit when all of the other
• 35:09
  moons in the inner part of the Neptune system
• 35:11
  are going around on a programme red orbit. So
• 35:14
  there is no real possibility that Triton
• 35:16
  could have formed where it is today. And
• 35:18
  that's led for many decades
• 35:21
  people to speculate as to the origin of
• 35:23
  Triton. And typically the two main ideas
• 35:26
  are either that it was formed by a
• 35:29
  transeptunion object or an object like Pluto
• 35:32
  coming into the Neptune system, colliding
• 35:34
  with the moon, knocking that moon out of
• 35:36
  orbit, and Triton being captured by the
• 35:38
  exchange of angular momentum. That's not
• 35:40
  really the favourite idea though. The
• 35:42
  favoured idea is that you had a binary object
• 35:44
  a bit like Pluto and Charon, or
• 35:47
  many of the transeptunion objects are these
• 35:50
  quite wide binaries of objects with similar
• 35:53
  sizes. You had one of these
• 35:55
  objects in the early days of the solar
• 35:57
  system, came very close to Neptune and you
• 35:59
  had this three body encounter where you've
• 36:01
  got Triton and um, its companion,
• 36:04
  which was possibly another object the size of
• 36:06
  Pluto, bound together, coming
• 36:09
  so close to Neptune that Neptune tore the
• 36:11
  couple apart. As it tore them apart,
• 36:14
  Triton was moving around its shared centre of
• 36:16
  mass with its partner at such a speed that it
• 36:19
  was moving slower than the escape velocity of
• 36:21
  Neptune. So one component of the binary was
• 36:23
  flung out and the other was captured. And
• 36:25
  that's a way to slow something down enough
• 36:27
  that it can be captured. So you trap Triton
• 36:30
  into this orbit that is retrograde,
• 36:33
  going around the wrong way around that
• 36:35
  quickly damps down to become circular because
• 36:38
  of tidal effects with Neptune.
• 36:41
  Now that seems to be the storey of Triton.
• 36:43
  And what supports this is that the regular
• 36:45
  satellites of Neptune are uh, pretty small
• 36:47
  and insignificant and smaller and
• 36:50
  more insignificant than the similar satellite
• 36:53
  systems of the other planets. They seem to be
• 36:55
  a bit smaller and more weedy than you'd
• 36:56
  expect them to be.
• 36:57
  Andrew Dunkley: Yeah.
• 36:58
  Jonti Horner: So the idea is that the capture of a moon the
• 37:00
  size of Triton would be pretty dramatic
• 37:03
  and would destabilise the Neptune system.
• 37:06
  The outside Triton, Nereid, which was the
• 37:09
  second moon to be found around Neptune, is a
• 37:11
  really interesting one because it's a fair
• 37:14
  bit further out than Triton but it's moving
• 37:15
  on this really elongated prograde orbit.
• 37:18
  And um, it's thought that that may well have
• 37:20
  been initially a regular satellite
• 37:23
  that was destabilised by Triton and flung
• 37:25
  onto this longer orbit. It's not really
• 37:27
  considered an irregular moon even though it
• 37:30
  behaves a bit like when it's really close in.
• 37:32
  But the moon's closer to Neptune, Neptune
• 37:34
  than Triton, of which there are seven known.
• 37:37
  We've got Naiad, Thalassa, Despina,
• 37:39
  Galatea, Larissa, Hippocamp and Proteus.
• 37:43
  They're all relatively small.
• 37:45
  Proteus is the biggest at 420ks.
• 37:48
  The rest are not quite as big. And um, the
• 37:51
  only images we've got up close and personal
• 37:53
  come from the Voyager 2 spacecraft in 1989
• 37:55
  that show these moons to be a little bit
• 37:57
  irregular. And um, they're also a little bit
• 38:00
  more stirred up and agitated in orbital
• 38:03
  tilts and orbital eccentricities than in,
• 38:06
  I mean they're barely tilted and they're
• 38:08
  barely on non circular orbits but you'd
• 38:10
  expect them, if they were properly original
• 38:12
  regulars to be totally circular.
• 38:15
  So the idea is maybe Triton stir them up.
• 38:19
  Now one of the suggestions to explain why
• 38:21
  they're all so small is that Triton as it was
• 38:23
  captured and then at its migrated senses,
• 38:26
  stirred them up enough that the original
• 38:27
  moons were destroyed. It stirred them onto
• 38:30
  all bits that collided with each other that
• 38:32
  formed a new disc of material. Some was lost
• 38:34
  but new moons were born of the process. And
• 38:37
  uh, that's become kind of like the canonical
• 38:40
  understanding of what we think happened to
• 38:42
  Neptune's moons in the early days.
• 38:44
  And that all a lot of background brings us to
• 38:46
  the new observations. As I say, the
• 38:48
  observations we had before came from
• 38:51
  Voyager 2. That's the up close and personal
• 38:54
  we've got. But there's been some new work
• 38:56
  done using the James Webb Space Telescope to
• 38:59
  get data ah on three of these moons,
• 39:02
  Lara, Larissa and Galatea being two of them
• 39:05
  and I think the third one was um,
• 39:07
  possibly um, the next one out
• 39:10
  Proteus have to double cheque that but I
• 39:12
  think it was. And what they found though was
• 39:14
  when they looked at both Larissa and
• 39:17
  um, Galatea, they
• 39:20
  found clear signals of clay
• 39:22
  type minerals on the surfaces of these moons.
• 39:26
  Now that's really unexpected.
• 39:29
  Clay minerals form at uh,
• 39:31
  temperatures high enough for you to have
• 39:33
  liquid water because clays are formed in the
• 39:36
  presence of liquid water. And the surfaces of
• 39:38
  moons in Neptune's orbit are blooming cold.
• 39:41
  You know, they're like 180200 degrees below
• 39:44
  freezing, which is not where you'd expect to
• 39:46
  find liquid water. So what the authors are
• 39:48
  proposing is that, uh, the surfaces of these
• 39:51
  moons, which look, to be honest, more like
• 39:53
  the surfaces of asteroids in the asteroid
• 39:54
  belt, are actually made from
• 39:57
  material that was once deep in the interior
• 40:00
  of moons that formed before, that therefore
• 40:03
  got hot enough for liquid water to be
• 40:05
  present. And we've talked a lot before about
• 40:07
  other moons in the solar system that have
• 40:09
  subsurface oceans. So you have these
• 40:12
  first generation of moons with their
• 40:13
  subsurface oceans water present
• 40:16
  high enough temperatures for you to develop
• 40:18
  all these clay minerals. Then those moons get
• 40:21
  stirred up. When Triton is captured, there
• 40:23
  are collisions, they're smashed apart, and
• 40:25
  you create a disc of material around Neptune
• 40:28
  that contains the material from the old
• 40:30
  moons, clays and all. Then you form new
• 40:33
  moons, and some of those new moons have that
• 40:35
  clay material on their surface. So what's
• 40:38
  been argued essentially, is that this, uh,
• 40:41
  detection of clays in the last place you'd
• 40:43
  expect to find them is like the smoking gun.
• 40:46
  It's a clue that is telling us about the
• 40:49
  heritage of this system, about events that
• 40:51
  happened more than 4 billion years ago.
• 40:53
  And he's telling us about this kind of
• 40:55
  collisional history and the dramatic storey
• 40:57
  of the Neptune satellite system. I think it's
• 40:59
  an astonish, astonishingly cool result. And
• 41:02
  it's really cool for me, as someone who's
• 41:04
  read about Triton a lot in the past, thought
• 41:06
  about it a lot, that the ideas that were
• 41:08
  being put around even when I was a teenager
• 41:10
  and listening to talks at my local astronomy
• 41:12
  society about the disruption of the Neptune
• 41:15
  satellite system are suddenly finding a test,
• 41:17
  thanks to people using James Webb. So theory
• 41:20
  making a prediction, that prediction getting
• 41:22
  more support. I think this is really lovely.
• 41:25
  Andrew Dunkley: Yeah, it is. Uh, and it certainly shows the
• 41:27
  worth of James Webb. And very soon, the
• 41:30
  Nancy Grace Roman Observatory, we're, uh,
• 41:32
  going to learn more and more about some of
• 41:33
  those, um, not so deep
• 41:36
  mysteries in the scheme of things. It's not
• 41:39
  far away, Neptune, but, uh, it's far enough
• 41:41
  away to still be mysterious in many
• 41:44
  ways. We really need to send a mission out
• 41:46
  there again soon, don't we?
• 41:48
  Jonti Horner: I was just thinking that there's been a lot
• 41:50
  of talk over the last decade
• 41:53
  or so, really, with solar system astronomers,
• 41:55
  astronomers getting more and more
• 41:56
  enthusiastic about the idea of sending new
• 41:59
  spacecraft out to Uranus and Neptune. Um,
• 42:02
  there's always debate when
• 42:05
  it's time to pitch new missions for NASA, of
• 42:07
  the different scales people put in competing
• 42:10
  proposals. And I know at the Last round there
• 42:13
  were a number of proposals of missions to
• 42:14
  Venus because we've not been there for a long
• 42:16
  time in terms of the Americans sent me. I
• 42:18
  know Japan had a fabulous orbit, are doing
• 42:21
  some great work there. There were also some
• 42:23
  really strong proposals of missions
• 42:26
  to Uranus and Neptune. I think this was a
• 42:28
  kind of medium sized stuff, so not Nancy
• 42:31
  Grace Roman pots of money, but more the $400
• 42:34
  million rather than $4 billion price
• 42:36
  missions. And in the last round I think the
• 42:39
  Venus missions won. But there is this growing
• 42:42
  longing to get missions to go back there
• 42:45
  and actually have orbiters because both
• 42:47
  Uranus and Neptune, the only up close and
• 42:49
  personal we've had with them were the Voyager
• 42:51
  spacecraft that launched in 1979.
• 42:55
  You know, launched back when I was one year
• 42:57
  old.
• 42:58
  Andrew Dunkley: Yeah.
• 42:58
  Jonti Horner: And flew past Uranus and Neptune. It was only
• 43:01
  Voyager 2 that got there. Voyager 1 went off
• 43:03
  on a different journey. So we've had one
• 43:05
  spacecraft that flew past faster than a
• 43:07
  speeding bullet, that spent less than a day
• 43:09
  within good imaging distance of these
• 43:11
  planets, return really tantalising
• 43:14
  information and then departed. And we've
• 43:17
  seen how much we learned from Galileo at
• 43:19
  Jupiter, from Cassini at Saturn, from Juno at
• 43:22
  Jupiter. So there's this growing body of
• 43:24
  scientists who are desperate to see this
• 43:26
  happen. Won't be cheap. And the other thing
• 43:29
  is, if such a mission was approved like next
• 43:31
  week, probably wouldn't launch for the best
• 43:34
  part of a decade and it would take the best
• 43:36
  part of a decade to get there. So it's the
• 43:38
  kind of thing where we're talking now. And
• 43:39
  I'll probably be retarded, retired when these
• 43:42
  spacecraft get there.
• 43:43
  Andrew Dunkley: I don't want to think about it.
• 43:47
  I don't think I'll be beyond retired.
• 43:49
  Jonti Horner: Let's just say that the sooner the better
• 43:51
  that we get there then.
• 43:53
  Andrew Dunkley: Yes, indeed, great storey. You can read
• 43:55
  about it online. Um, plenty of, uh, platforms
• 43:58
  have got storeys about uh, Neptune
• 44:01
  satellites. You can read the scientific paper
• 44:03
  in detail at the journal Science
• 44:06
  Advances. That brings us to the end.
• 44:08
  Jonty, thank you very much.
• 44:10
  Jonti Horner: That's an absolute pleasure. Thank you for
• 44:11
  having me.
• 44:12
  Andrew Dunkley: Always a pleasure. Professor, uh, John de
• 44:14
  Horner, professor of Astrophysics at the
• 44:17
  University of Southern Queensland. Between
• 44:19
  episodes, don't forget to visit our website
• 44:21
  for um, things to see and do like
• 44:24
  you can, um, send us messages or questions
• 44:26
  through the Ask me anything button at the
• 44:28
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• 44:31
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• 44:33
  leave reviews about the podcast wherever you
• 44:35
  listen to us and visit, uh, the Space
• 44:38
  Nuts shop while you're there.
• 44:40
  Um, Father's Day in Australia coming up
• 44:43
  soon. That's, you know, you might find
• 44:45
  something good in there. A couple of good
• 44:46
  books have been released lately. You might
• 44:48
  like the little cat, maybe. Uh,
• 44:51
  and, uh, thanks to Huw in the studio couldn't
• 44:54
  be with us today. He was actually driving
• 44:56
  over to, um, get to the studio
• 44:59
  for us today. But then, uh, as was
• 45:02
  the case with Neptune, uh, he got hit by a
• 45:05
  Mitsubishi Triton and that was the end of
• 45:07
  that. Uh, and from me, Andrew Dunkley. Oh,
• 45:09
  he's actually okay, you know, he just
• 45:12
  couldn't make it. And from me, Andrew
• 45:13
  Dunkley. Thanks for your company. We'll catch
• 45:14
  you on the next episode of Space Nuts. Bye.
• 45:17
  Bye. You've been listening to the
• 45:20
  Space Nuts
• 45:20
  Jonti Horner: podcast, available at
• 45:23
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• 45:25
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• 45:28
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  demand@bytes.com.
• 45:32
  Andrew Dunkley: this has been another quality podcast
• 45:34
  production from bytes.com.
• 45:36
  Jonti Horner: um,