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Theia’s True Origins, 40,000 Asteroids & Enceladus’ Organic Mystery | Space Nuts: Astronomy... · Space News Today

• 0:00
  Hi there. Thanks for joining us on Space
• 0:02
  Nuts, where we talk astronomy and space
• 0:04
  science. My name is Andrew Dunley. Great
• 0:06
  to have your company. Coming up on this
• 0:09
  episode, uh, a new study from the Max
• 0:11
  Plank Institute shedding some new light
• 0:13
  on the the Earth relationship, which
• 0:16
  might surprise you. And just when you
• 0:18
  thought it was safe to go back to sleep
• 0:21
  at night, 40,000 new uh near Earth
• 0:24
  asteroids have been discovered. Only
• 0:26
  40,000. And they're all coming our way.
• 0:29
  No, they're not. Uh, the Search for Life
• 0:31
  just got another um a bit closer uh
• 0:34
  thanks to some Cassini data and three
• 0:37
  Atlas still making the news. We'll talk
• 0:40
  about all of that on this episode of
• 0:42
  Space Nuts.
• 0:43
  >> 15 seconds. Guidance is internal. 10 9
• 0:48
  Ignition sequence start.
• 0:50
  >> Space Nuts.
• 0:51
  >> 5 4 3 2
• 0:53
  >> 1 2 3 4 5 5 4 3 2 1
• 0:56
  >> Space nuts. astronauts report. It feels
• 0:58
  good.
• 1:00
  >> And we rolled out the red carpet because
• 1:02
  he's back. It's Professor Fred, what's
• 1:04
  an astronomer at large? Hello, Fred.
• 1:06
  >> Hi, Andrew. I'm actually looking for the
• 1:08
  red carpet.
• 1:09
  >> Yeah, I rolled it back up again. It's
• 1:12
  had a few moth holes in it. [laughter]
• 1:14
  >> Yeah. But he's glad to hear it.
• 1:16
  >> Good.
• 1:17
  >> And you, too. And um Well, we've missed
• 1:20
  you. No, wait a minute. No, you've
• 1:21
  missed one or the other. Yes, we did
• 1:24
  have a few people starting to um I found
• 1:26
  in radio if you were away for more than
• 1:28
  about 3 or 4 weeks people started
• 1:30
  ringing the station and emailing to say
• 1:33
  where's Joe Blogs or where's you know
• 1:36
  this started happening with you Fred so
• 1:38
  >> oh seriously
• 1:39
  >> where's Fred where's Fred what's going
• 1:40
  on with Fred what happened to Fred
• 1:42
  >> uh and and funnily enough I I was able
• 1:45
  to say yeah I don't know
• 1:48
  [laughter]
• 1:48
  >> seen him for weeks
• 1:50
  >> he's just disappeared but no he's back.
• 1:53
  He's back. So, where did where did you
• 1:55
  go? What was the give us the give us the
• 1:57
  the the preed version of your seven
• 1:59
  weeks away.
• 2:01
  >> Three weeks um leading one of man's
• 2:04
  tours uh which uh is the third big one
• 2:07
  we've done this year actually um after
• 2:10
  the Arctic in in January and February
• 2:12
  and then it was uh Western Australia in
• 2:14
  the middle of the year and then this
• 2:16
  time we went to Japan. Uh, so we had a
• 2:18
  tour that took in uh interesting places
• 2:21
  like Osaka and Kyoto and Tokyo. And um
• 2:25
  Mani and I actually made a side trip
• 2:27
  down to Hiroshima, which is a place I've
• 2:29
  always wanted to visit and I'm very glad
• 2:31
  I did.
• 2:32
  >> Very sobering place to be. Uh but a
• 2:35
  welcoming city as well. It was um it was
• 2:38
  a pleasure to be there.
• 2:39
  >> Uh and then um we wound up actually in
• 2:41
  Hokkaido right in the north of of Japan
• 2:44
  where it was essentially coming on to
• 2:46
  winter. uh they they get lots and lots
• 2:48
  of snow up there. It's a lot similar to
• 2:51
  um to the Arctic, even though it's at a
• 2:52
  much lower latitude. Um yeah, that was
• 2:55
  all fun. So, we came back, we had four
• 2:56
  nights in Sydney at home [laughter] in
• 2:58
  our own bed, do the washing, and then
• 3:00
  off again to a conference on dark skies
• 3:02
  in County Mayo in Ireland. Uh we were in
• 3:05
  Ireland for about a week, a little bit
• 3:07
  more than a week. We did some touring
• 3:08
  down in the south. We blew a kiss to the
• 3:12
  Blanny Stone. I did.
• 3:14
  >> Yeah. [laughter]
• 3:15
  I wasn't game to kiss the Blney Stone
• 3:17
  because you have to be upside down.
• 3:18
  Yeah.
• 3:19
  >> Doesn't suit me at all.
• 3:20
  >> We didn't do that either.
• 3:22
  >> No. [snorts] So, we blew it a kiss,
• 3:23
  which is enough apparently to get the
• 3:25
  gift of the gab. And then, in fact,
• 3:27
  Blani was a delightful place. It was the
• 3:29
  one sunny afternoon we had in in um
• 3:31
  Ireland and it was lovely. Such an
• 3:33
  amazing castle and the crowds are
• 3:35
  picture perfect. Uh then we went over to
• 3:37
  Scotland, spent some time with my two
• 3:40
  daughters. Had a great time with them.
• 3:42
  Took a weekend out. Uh we all beled off
• 3:45
  to St. Andrews where I was educated. Uh
• 3:47
  a town that's very close to my heart. We
• 3:49
  had a great time there. Didn't do any
• 3:50
  golf. I'm sorry, but we did walk past
• 3:52
  the old course and thought of you with
• 3:54
  your golf clubs and that they don't
• 3:57
  float and things like that.
• 3:58
  >> And and
• 4:00
  then after that we um took the train
• 4:03
  down to Birmingham from Edinburgh and
• 4:05
  that was pleasant. And at Birmingham, we
• 4:07
  got on a plane and went to Cyprus uh in
• 4:09
  the eastern end of the Mediterranean and
• 4:11
  had we actually had a holiday six
• 4:13
  >> nights. Found an observatory, a brand
• 4:15
  new one called Trudeau.
• 4:17
  >> Trudeau observatory. Yes, we did. We
• 4:19
  Manne checked it out as she does with
• 4:20
  these things. And so we made a
• 4:22
  pilgrimage up into the hills, not very
• 4:24
  far from the highest point in the island
• 4:26
  actually, Mount Olympus. Uh but um it's
• 4:29
  got its own little mountain has uh uh
• 4:31
  the Trudeau Observatory. Uh we went up
• 4:33
  there. We went completely unannounced.
• 4:35
  They just had a tour group through. So,
• 4:37
  there were two coaches which were just
• 4:39
  about to set off down this road that was
• 4:42
  slightly narrower than a coach. Uh, and
• 4:44
  an angle of 45 degrees. Uh, if we'd been
• 4:48
  um, you know, if we'd been half an hour
• 4:49
  later, we'd have probably not been able
• 4:51
  to get there because these damn coaches
• 4:53
  going by. But when we arrived, um, that,
• 4:56
  you know, they just got rid of all the
• 4:57
  coach party and we turned up and said,
• 4:59
  "We're astronomers. Uh, can we have a
• 5:01
  look?" And they said, "Oh, no, no,
• 5:02
  you'll have to wait till the next tour."
• 5:04
  Uh but we managed to get hold of the
• 5:06
  events manager who said, "Yeah, come in.
• 5:08
  Let's talk about what we do and all the
• 5:09
  rest of it." Had a great time. Awesome.
• 5:11
  So that was very very nice.
• 5:12
  >> Yeah.
• 5:13
  >> And if she's a Space Nuts listener, um
• 5:16
  nice to have met you. I think it was
• 5:18
  Arena was her name.
• 5:20
  >> Nice.
• 5:20
  >> Greek version of that. And then came
• 5:22
  home uh and we came home last week and
• 5:24
  we're now jetlagged.
• 5:26
  >> Yeah, it's it's hard to get over
• 5:27
  jetlagged. I think it's it's an age
• 5:28
  thing, Fred. We can't
• 5:30
  >> could be except um my other half is a
• 5:32
  lot younger than I am and she's jetlike
• 5:34
  too. [laughter]
• 5:36
  >> Just goes a bit territory.
• 5:38
  >> Yeah. Well, I I got a golf story for
• 5:39
  you. While you were away, I won a I won
• 5:41
  a championship.
• 5:42
  >> You You did? Yeah.
• 5:44
  >> Well done. So, it was um
• 5:46
  >> 17 years between
• 5:48
  >> uh uh Well, no, I came uh in the state
• 5:51
  championships. I came third on handicap
• 5:55
  and uh top 10. I finished ninth, I
• 5:57
  think.
• 5:58
  >> Fantastic. in the state championship,
• 5:59
  but then we had our own um championship
• 6:01
  at do golf club the other day and I I
• 6:04
  managed to win one of those. So
• 6:05
  >> that's very good.
• 6:06
  >> And then today just before this I played
• 6:09
  in the proam because we're hosting the
• 6:11
  New South Wales women's open qualifying
• 6:14
  event. So
• 6:15
  >> played with a young lass from Melbourne.
• 6:17
  Her name is Piper. Um Piper
• 6:21
  oh gone blank. Um anyway, come back to
• 6:25
  me. Uh lovely young lady, hits a really
• 6:28
  mean ball and wishing her well. Hope she
• 6:31
  makes it to the New South Wales Open and
• 6:33
  um I'll be watching her career closely.
• 6:35
  So very good.
• 6:37
  >> She beat you.
• 6:38
  >> Uh gosh, yes. Oh yes. Well, it was a
• 6:41
  team's event today, so we were
• 6:42
  technically playing together, but she
• 6:43
  out drove us miles. Yes. She could hit
• 6:47
  it a long way, but uh just a pleasure.
• 6:50
  Just a delight. We had a good day.
• 6:53
  >> We should get down to it, Fred.
• 6:55
  >> We should. Yes, we're not here to talk
• 6:57
  about golf, are we? Although it doesn't
• 6:59
  seem that way.
• 7:00
  >> Not for a change. Um, our first story
• 7:03
  takes us back 4 and a half billion years
• 7:05
  when our neighboring world known as Thea
• 7:08
  smashed into us and all hell broke
• 7:10
  loose, literally and figuratively. But,
• 7:13
  uh, a new study has just been released
• 7:15
  from the Max Plank Institute that's shed
• 7:17
  a bit of new light on the the earth
• 7:20
  relationship. Uh it it doesn't sound
• 7:22
  like this was a what we originally
• 7:25
  thought, just some random thing coming
• 7:27
  in and hitting us. There's there's more
• 7:29
  to the story now.
• 7:32
  >> There is. Yes. Um sorry, Andrew, you
• 7:34
  broke up there, but I think I know what
• 7:35
  you said. Uh
• 7:37
  um the the story of the of course this
• 7:40
  has been the the principal theory uh for
• 7:43
  the origin of the moon for at least the
• 7:44
  last 60 years. uh when the Apollo
• 7:47
  astronauts brought back what was it 380
• 7:49
  kg of lunar rock and soil which is still
• 7:52
  being analyzed. Um so uh thea is the
• 7:56
  hypothesized planet uh perhaps
• 8:00
  protolanet is a better word because this
• 8:02
  was at a time when the solar system was
• 8:04
  still in its infancy 4 and a half
• 8:05
  billion years ago. Um and this object uh
• 8:09
  basically clouded the earth. Uh and uh
• 8:12
  we think that what happened in the
• 8:14
  aftermath of the that collision was a
• 8:16
  cloud of debris raised from the surface
• 8:19
  of the earth went into orbit around the
• 8:21
  earth and eventually coalesed to form
• 8:22
  the moon. And so we've we've um had
• 8:26
  puzzles which you and I have spoken
• 8:28
  about a number of times as to why it is.
• 8:32
  Well, let me let me step back a bit. The
• 8:34
  the first theory was that because this
• 8:37
  is a smaller object hitting a bigger
• 8:39
  object. So theor is thought to have been
• 8:41
  half the size of the earth to get the
• 8:43
  dynamics right. Um the earth's a bigger
• 8:46
  planet. Uh what you would expect is that
• 8:49
  the the debris cloud raised from the
• 8:52
  earth when the collision happened would
• 8:54
  be mostly made of the material. Um, and
• 8:58
  that's been a puzzle for a long time
• 9:00
  because most of the lunar rocks and soil
• 9:04
  have the same isotopic signature, which
• 9:07
  we've talked about before as well, the
• 9:10
  same isotopic signature as the Earth.
• 9:11
  They're identical uh to the Earth's
• 9:14
  rocks. And so that was seen as a puzzle.
• 9:16
  And then about probably five years ago
• 9:18
  or so, we did cover it on Space Note.
• 9:20
  some Japanese researchers um figured out
• 9:22
  that if the Earth was still effectively
• 9:24
  molten at that time, if it was still a
• 9:27
  magnum magma world when the collision
• 9:29
  happened, then you'd get um a moon that
• 9:32
  was formed largely of of Earth
• 9:34
  compounds.
• 9:36
  So, um what has now happened is that um
• 9:39
  a close examination has been made and as
• 9:42
  you're right, it's the Maxplank
• 9:44
  Institute for Solar System Research
• 9:46
  along with the University of Chicago. um
• 9:48
  they've they've really honed in on the
• 9:52
  uh the the exact uh details of the
• 9:56
  isotopes in rocks from the earth, the
• 9:59
  moon and meteorites because they're part
• 10:02
  of the story too. And and it's not just
• 10:05
  the sort of isotopes that have been
• 10:06
  looked at before. These are iron,
• 10:08
  chromium, malibdum, malibdinum,
• 10:11
  zirconium. All these iso that these um
• 10:15
  chemical elements their isotope data
• 10:18
  have been analyzed to look again at what
• 10:22
  we find because yes we we still find
• 10:25
  that the the earth and the moon have
• 10:27
  very similar isotopic mixes. Uh but then
• 10:31
  you can identify some slight differences
• 10:34
  that are attributed to be isotopes that
• 10:37
  have come from thea itself. So they can
• 10:40
  tease out what was Thea and what was
• 10:43
  Earth. And it turns out that when you do
• 10:46
  that, you still get a similar picture
• 10:49
  that the isotope ratios on Thea were
• 10:53
  probably very similar to what they are
• 10:56
  on Earth. Um, and that is
• 11:01
  symptomatic, if I can put it that way,
• 11:03
  of the Earth and Thea being born close
• 11:08
  together. And the reason why we think
• 11:10
  that is that when you look at the solar
• 11:12
  system, you find that these isotope
• 11:15
  ratios change depending on how far out
• 11:18
  you are from the sun. So if you've got
• 11:20
  two planets with very similar isotope
• 11:23
  ratios, then what you can deduce from
• 11:26
  that is that they were orbiting the sun
• 11:29
  close together. And that makes complete
• 11:32
  sense because eventually they run into
• 11:33
  one another. Um but what the outcome of
• 11:37
  this research is is that uh thea was not
• 11:40
  just a random object that ran into the
• 11:42
  earth in the early solar system. It was
• 11:44
  actually if not a companion of earth but
• 11:47
  something in a very similar orbit. So
• 11:50
  you know maybe we had Mercury, Venus,
• 11:51
  the Earth, Mars as the rocky planets. Um
• 11:55
  although that order, you know, I've made
• 11:57
  that up, but that's the kind of thing
• 11:59
  it's it's bringing bringing Thea into
• 12:02
  the picture as something that would have
• 12:03
  been maybe had it not collided with the
• 12:06
  Earth, it would have been uh the ninth
• 12:08
  planet uh in the inner part of the solar
• 12:10
  system. So uh a very nice piece of work,
• 12:13
  some very very careful studies there
• 12:15
  that I think has raised a lot of um
• 12:16
  interest in the uh uh the planetary
• 12:20
  science community. Yeah, I suppose that
• 12:22
  sort of uh confirms that it was part of
• 12:25
  the solar system and not just some
• 12:26
  random thing passing through knocking us
• 12:29
  over in the process.
• 12:31
  >> That's right. Yeah. And um and I should
• 12:33
  just explain how how the the remnants
• 12:36
  have been the the isotopes have been
• 12:39
  determined and it's by looking at things
• 12:41
  that we find in the crust of the earth.
• 12:43
  Uh because we know that the heavy
• 12:45
  elements would have already sunk to the
• 12:47
  to the center of the earth when that
• 12:49
  collision happened. So when we think
• 12:51
  find things like these malib malibdinum
• 12:54
  iron zirconium things of that sort we
• 12:58
  can infer that some of that actually
• 12:59
  came from theory itself and that's how
• 13:02
  the similarity has been deduced along
• 13:05
  with looking at meteorite samples too.
• 13:07
  So you're right um it it is not
• 13:11
  something that's come from another solar
• 13:13
  system like our current visitor Threei
• 13:15
  Atlas. Uh it's it's definitely a
• 13:18
  homegrown planet that we collided with.
• 13:21
  >> Okay. And now it's sort of a well it's
• 13:23
  not a part of us. There's bits and
• 13:25
  pieces of it but um most of it sort of
• 13:27
  vanquished into into the never never
• 13:29
  didn't it?
• 13:30
  >> Yeah. A lot of it would have done but um
• 13:32
  some of it's in the moon. Some of it's
• 13:33
  on the earth as well.
• 13:35
  >> Yeah. All right. Uh so I guess some new
• 13:38
  information from the Max Planck
• 13:40
  Institute about uh Thea being a part of
• 13:43
  the inner solar system. If you'd like to
• 13:44
  read about that, there's a really great
• 13:46
  article at scienceblog.com.
• 13:49
  This is Space Nuts with Andrew Dunley
• 13:51
  and Professor Fred.
• 13:53
  Let's take a break from the show and
• 13:55
  talk about our sponsor, NordVPN. Now, if
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• 15:17
  >> And I feel
• 15:18
  >> space nuts. Uh, now to some really good
• 15:20
  news, Fred. 40,000 near-earth asteroids
• 15:24
  have been discovered. Is that all? Is
• 15:26
  that all they could find?
• 15:28
  >> Well, it's Yeah, I mean, we've for a you
• 15:30
  know, for a long time we've known of
• 15:32
  39,999.
• 15:34
  [laughter]
• 15:36
  Maybe not for very long because because
• 15:37
  we're discovering asteroids at a very
• 15:39
  prolific rate at the moment and that
• 15:41
  comes about because we've got such good
• 15:42
  technology discovering them. Um, and so
• 15:46
  yes, this is a milestone that's been
• 15:47
  celebrated by ISSa, the European Space
• 15:49
  Agency. Uh, and you know, so they've
• 15:52
  they've put out a a press release saying
• 15:55
  40,000 near-ear asteroids discovered.
• 15:57
  Uh, what do we mean by a near-earth
• 15:59
  asteroid? It's one that approaches
• 16:01
  within about 45 million kilometers of
• 16:05
  the Earth. And that's nearly a third of
• 16:08
  the distance to the sun. So it's when
• 16:11
  you say near, it's it's a fairly
• 16:13
  relative term. It's one uh with objects
• 16:16
  that that can get within that distance
• 16:18
  of Earth. Then there's another subset of
• 16:21
  those though that we tend to call PHAS,
• 16:24
  potentially hazardous asteroids. Uh and
• 16:28
  um there are something like I think if I
• 16:30
  remember right, it's about two and a
• 16:31
  half thousand of those. And they're the
• 16:33
  ones whose orbits cross the orbit of the
• 16:35
  Earth.
• 16:36
  >> Um and so they are potentially
• 16:38
  hazardous. So they're the ones that we
• 16:40
  keep an eye on all the time uh
• 16:42
  monitoring where they are uh and
• 16:45
  checking forward uh in computers once we
• 16:48
  know their orbits checking forward as to
• 16:50
  whether there's any likelihood of
• 16:52
  collision. The good news is is that
• 16:54
  there's not uh over the next 100 years
• 16:56
  or so we've got a fairly clean sweep of
• 16:59
  things at least things bigger than about
• 17:01
  140 mters across and they can be very
• 17:04
  dangerous. they can be they could be
• 17:06
  city destroyers or even state
• 17:08
  destroyers. So um so keeping an eye on
• 17:11
  those is important. Uh and I think you
• 17:13
  know the reason why um issa has
• 17:16
  highlighted this is because it does
• 17:17
  highlight the whole um regime of
• 17:20
  planetary defense. Uh that's a very
• 17:22
  active area in astronomy and um actually
• 17:26
  almost civil defense as well. It's not
• 17:28
  just astronomy that is concerned with
• 17:30
  that. I I think I probably mentioned
• 17:32
  before when I was at the IAU a couple of
• 17:34
  years ago um I actually got myself into
• 17:36
  a meeting uh which was the planetary
• 17:38
  defense agency
• 17:41
  uh talking about uh their next
• 17:43
  activities which included a a mock um a
• 17:47
  mock threatened planetary asteroid
• 17:49
  impact and how all the services would
• 17:52
  deal with that and you know the astron
• 17:53
  from the astronomers right to the people
• 17:56
  who get the fire engines out to put out
• 17:58
  the fires and things of that. thought it
• 18:00
  was very interesting thing to watch. So,
• 18:02
  um what it did was reure reassured me
• 18:04
  that were in quite good hands. Uh but
• 18:07
  yeah, the bottom line, uh 40,000
• 18:09
  near-earth asteroids known. Uh the good
• 18:12
  news is always that the big ones, uh
• 18:14
  which are the most dangerous ones,
• 18:16
  they're the easiest to find. And we
• 18:18
  think we know pretty well all of the
• 18:21
  asteroids bigger than a kilometer, which
• 18:24
  would be um dinosaur killers. they would
• 18:27
  wipe out, you know, there'd be mass
• 18:28
  extinction objects. Uh we think one of
• 18:31
  those hits the earth roughly every 200
• 18:35
  million years. Uh it's 66 million years
• 18:37
  ago since the last one did, which was
• 18:40
  was the one that wiped out the the
• 18:42
  dinosaurs. Um since then though, we've
• 18:44
  learned a lot about not only about
• 18:46
  asteroids, but about how we might
• 18:48
  deflect uh an asteroid if uh if there
• 18:52
  was one that could be shown to be on a
• 18:54
  collision course with Earth. And you
• 18:56
  have I you and I have talked at length
• 18:58
  and with great enthusiasm about the Dart
• 19:00
  mission back in 2022 in the double
• 19:02
  asteroid redirection test uh a really
• 19:06
  well put together experiment by NASA
• 19:08
  which uh succeeded in changing the orbit
• 19:12
  of a little world called Dorphos uh and
• 19:15
  that's great news because we know that
• 19:17
  it's now possible to do that. And just
• 19:19
  as a postcript to this story, um, ISSA
• 19:22
  currently has a spacecraft called HIA, H
• 19:25
  E R A on its way to Dorphos to check out
• 19:29
  what the result of that impact was. It's
• 19:32
  going to study that little world, look
• 19:34
  at the debris that was raised by the
• 19:37
  impact, uh, get a much better idea of
• 19:39
  whether it's a it really is just a
• 19:41
  rubble pile, which we think it probably
• 19:43
  is, and just, uh, learn more about what
• 19:46
  an impact by uh, a spacecraft does to an
• 19:50
  asteroid because that's the key thing.
• 19:52
  If we're going to have to save ourselves
• 19:54
  one day by doing this, we want to know
• 19:56
  as much about it as possible. And if I
• 19:58
  remember rightly, here will reach
• 20:00
  Dimorphus. I think it's late next year.
• 20:02
  I think it's towards the end of next
• 20:03
  year.
• 20:04
  >> Very exciting. Yeah. Nice to get a
• 20:07
  follow-up on that story, too. Yeah. Um
• 20:09
  and of course this is not the end of
• 20:12
  finding these kinds of things cuz uh the
• 20:14
  Vera C Rubin Observatory in Chile is
• 20:18
  it's it's not its primary role but it
• 20:20
  will be looking for other um near-Earth
• 20:24
  objects and they expect it to find tens
• 20:27
  of thousands of them.
• 20:28
  >> Absolutely. That's right. By this time
• 20:30
  next year we might be talking about
• 20:32
  80,000 or 100,000 nearear asteroids
• 20:35
  discovered. And of course again that's a
• 20:37
  good news story because as soon as you
• 20:39
  discover one of these things first thing
• 20:41
  you do is put its orbital elements into
• 20:43
  the computer grind away uh look at its
• 20:46
  trajectory in the future and that is all
• 20:49
  done automatically and if there is a
• 20:51
  need uh the system will raise alerts
• 20:53
  that there could be a collision uh in a
• 20:56
  certain window in the future. So um that
• 20:58
  whole process is really part of
• 21:01
  planetary defense. It's what's
• 21:02
  safeguarding us from the asteroid
• 21:03
  hazard.
• 21:04
  >> Yeah. Yeah. Um I I read a story the
• 21:08
  other day. I think Vera C. Rubin um had
• 21:11
  had it took its first picture, first
• 21:13
  light or I think they refer to it as in
• 21:15
  was it June or July this year?
• 21:17
  >> It was Yeah, I think it's about Yeah.
• 21:19
  >> Yeah. Uh so we almost at the pointy end
• 21:22
  of that um that observatory kicking into
• 21:25
  action.
• 21:25
  >> That's right. If I remember rightly, I
• 21:27
  might have these figures slightly wrong,
• 21:28
  but it was something like was it a
• 21:30
  10-hour set of observations they took
• 21:32
  and they discovered more than a thousand
• 21:34
  asteroids. Yeah. Period. So, you know,
• 21:36
  imagine what it's going to be like. This
• 21:37
  thing looks at the entire southern sky
• 21:40
  every three nights.
• 21:42
  >> That's incredibly remarkable.
• 21:43
  >> Yeah. It's quite
• 21:44
  >> Yeah. Um like we we were so blessed to
• 21:47
  be able to get so much information out
• 21:49
  of um um Oh gosh, my brain's not working
• 21:53
  today. Um the other observatory, the one
• 21:56
  that's out on in the L2.
• 21:58
  >> Oh yeah, you you mean the James Webb
• 22:00
  telescope?
• 22:00
  >> James Webb. Gosh, why couldn't I think
• 22:02
  of that? But um working side by side
• 22:05
  with Ver Rubin, this is just going to
• 22:07
  open up a whole new
• 22:09
  >> Yep, that's right. List of new
• 22:12
  discoveries. Yeah. Yeah. Very exciting.
• 22:15
  >> Uh if you would like to read about those
• 22:17
  40,000 near-earth objects,
• 22:20
  if you really, you know, you can go to a
• 22:22
  horror movie instead. It probably much
• 22:24
  more fun. But um 40,000 near-earth
• 22:26
  objects, you can do that through the
• 22:28
  European Space Agency website.
• 22:33
  Okay, we checked all four systems and
• 22:36
  >> space nets.
• 22:37
  >> Now, this this is a story that really
• 22:38
  excites me because um we've talked about
• 22:41
  this so many times, but um this this
• 22:45
  story I saw pop up last weekend and we
• 22:48
  we have been talking so much about the
• 22:51
  potential for life elsewhere. haven't
• 22:54
  found it yet, but the signs are starting
• 22:56
  to build, particularly within our own
• 22:59
  solar system. And this particular story
• 23:03
  is is one again where we have taken a
• 23:07
  bit of old data and reanalyzed it. And
• 23:10
  this involves the Cassini uh mission uh
• 23:14
  which has been taking samples of the
• 23:17
  eruptions from Enceladus. And what
• 23:21
  they've discovered is very very uh
• 23:24
  exciting.
• 23:25
  >> It is. Uh that's right. And uh yes,
• 23:28
  Cassini, you know, uh it was active if
• 23:30
  if I remember rightly between
• 23:33
  200
• 23:35
  I think was it 2004? Yes. And 2017. So
• 23:39
  that was the period when Cassini was
• 23:41
  collecting its data. And as you've just
• 23:43
  said, we're still learning things from
• 23:46
  those data. Uh, and in particular, what
• 23:49
  has been identified is some previously
• 23:52
  unknown organic chemicals in the ice
• 23:56
  grains that Cassini flew through, which
• 23:59
  are erupting, as you said, from the ice
• 24:02
  geysers in near the southern uh pole,
• 24:05
  the south pole of Enteladus, that little
• 24:08
  500 kilometer diameter world, which is
• 24:11
  one of Saturn's moons with the structure
• 24:13
  that we think is fairly common out in
• 24:15
  that part of the solar system, a rocky
• 24:18
  body overlay with a liquid ocean with
• 24:21
  ice on top of that. And the pressure of
• 24:23
  the ice is what's keeping that ocean
• 24:24
  liquid along with the the squeezing and
• 24:27
  squashing of the of the rocky part of
• 24:29
  the the body by the tidal forces exerted
• 24:32
  by the giant planet Saturn uh next door.
• 24:35
  And Saturn, by the way, um we've just
• 24:37
  gone through its ring plane. So Saturn,
• 24:39
  if you looked at Saturn through a
• 24:40
  telescope tonight or anytime within the
• 24:43
  next couple of weeks, you won't see any
• 24:44
  sign of the rings because we're they're
• 24:46
  edge onto us.
• 24:46
  >> Oh, okay.
• 24:47
  >> Y just a little aside there. Um so what
• 24:51
  uh what has happened is that uh we've
• 24:55
  we've known about these organic
• 24:58
  chemicals in ice grains which we we know
• 25:02
  come from Enceladus because they
• 25:04
  actually feed into the outer ring of
• 25:07
  Saturn something called the E-ring which
• 25:09
  is a very diffuse ring and we know that
• 25:12
  the material in that ring the ice
• 25:14
  crystals in that E-ring actually come
• 25:16
  from the south pole of of Enceladus.
• 25:19
  And those have been well analyzed um by
• 25:22
  Cassini and also by other observations.
• 25:26
  And so it was known that there were
• 25:27
  organics in there. But the question was
• 25:31
  these ice crystals may have been in
• 25:34
  orbit. They may have been in space for
• 25:35
  centuries. And so their chemical
• 25:39
  structure might well have been modified
• 25:43
  first of all by the the sun's
• 25:44
  ultraviolet radiation which tends to
• 25:47
  change chemistry. uh and the the solar
• 25:50
  wind, the wind of subatomic particles
• 25:52
  that comes from the sun that too can
• 25:54
  change the chemistry of particles uh
• 25:57
  grains of you know of of of ice with
• 26:00
  their with their organics uh on them the
• 26:03
  organic chemicals uh it can change their
• 26:05
  chemistry and so there was always a
• 26:07
  question whether these quite complex
• 26:10
  organic chemicals that were identified
• 26:13
  uh in the E-ring uh whether they are
• 26:17
  telling knew that that's how
• 26:19
  [clears throat] the ice crystals were
• 26:21
  when they came when they were spat out
• 26:23
  from Cassini's south pole. Um, it puts
• 26:26
  doubt on it. And so what this new
• 26:29
  analysis does is looks back to one of
• 26:32
  the flythroughs of uh Cassini through
• 26:36
  the ice plumes back in 2008.
• 26:40
  uh Cassini flew through the plume at
• 26:42
  about um 18 kilometers/s
• 26:45
  at a height of about 20 kilometers above
• 26:47
  the surface of Cassini. And so the the
• 26:51
  ice crystals that it passed through um
• 26:54
  only a few minutes earlier were actually
• 26:57
  water in the ocean of Enceladus. So
• 27:01
  these are fresh crystals of ice straight
• 27:04
  from the ocean. In other words, they,
• 27:06
  you know, they're effectively samples of
• 27:07
  the ocean water. And what they've
• 27:10
  succeeded in showing, uh, what the
• 27:12
  scientists who have done this succeeded
• 27:13
  in showing is that the chemistry is
• 27:16
  still there. The the organic, the
• 27:18
  complex organics are there in this fresh
• 27:22
  ocean spray, as they call it. I love
• 27:24
  that idea. It's an ocean spray, but it's
• 27:26
  ice crystals. And there's a whole you
• 27:30
  know a whole list of um things like
• 27:33
  esters, aromatics, hetereroatombearing
• 27:36
  organics. These are chemical terms that
• 27:39
  um I'm not that familiar with because
• 27:41
  chemistry was not my strong point. Uh
• 27:44
  but these chemicals are yes they are
• 27:47
  there in the ocean of Enceladus. Uh and
• 27:50
  what that has done is raised again the
• 27:53
  possibility that living organisms might
• 27:55
  exist in that ocean. uh and that because
• 27:58
  these chemicals are as we keep on saying
• 28:00
  the building blocks of life. Uh so just
• 28:04
  maybe there's something swimming around
• 28:05
  in the ocean of Enceladus that we are
• 28:07
  yet to discover.
• 28:09
  >> Yes. And wouldn't it be exciting? And uh
• 28:11
  hopefully in the not too distant future
• 28:13
  we'll be able to confirm it. Um I think
• 28:17
  people are starting to get very
• 28:18
  confident about the possibility though.
• 28:20
  >> Yeah. Yep.
• 28:20
  >> Yeah, that's right.
• 28:21
  >> So um fingers crossed. But uh yeah, the
• 28:24
  signs are starting to really build and I
• 28:25
  I even though it'll be probably one of
• 28:28
  the most exciting things ever discovered
• 28:31
  should we succeed in finding evidence of
• 28:33
  life elsewhere, we also probably
• 28:36
  shouldn't be surprised because water we
• 28:40
  now is know prolific throughout the
• 28:42
  universe.
• 28:43
  >> We know there are probably exoplanets
• 28:47
  orbiting almost every star in the
• 28:49
  universe. stands to reason that
• 28:51
  somewhere somewhere out there there's
• 28:54
  there's got to be some form of life.
• 28:56
  Even if it's only microbial, but
• 28:59
  >> or krill.
• 29:01
  >> Krill would be exciting. Green slime is
• 29:04
  what we're likely to find. I think
• 29:06
  >> green slime. Green slime will do.
• 29:08
  >> Green. Green slime would do it. That's
• 29:10
  right. It would indeed.
• 29:11
  >> Indeed. If you'd like to read up on that
• 29:13
  story about the latest from Enceladus,
• 29:16
  you can find it in the journal Nature
• 29:18
  Astronomy
• 29:22
  Space Nuts. One last story in this
• 29:25
  episode, Fred, and it's a bit of an
• 29:27
  update on three Atlas, the exo comet
• 29:30
  that is currently uh doing its thing.
• 29:34
  It's doing whatever it wants really. Uh
• 29:36
  but um it it's uh it's it's sort of
• 29:39
  reappeared and they're getting some
• 29:41
  great pictures of it, not only from
• 29:42
  Earth, but from Mars. And um some of
• 29:47
  these photos are extraordinary.
• 29:49
  Yes, they are. They're when you look at
• 29:51
  them, they're a little bit underwhelming
• 29:53
  until you realize that they've they've
• 29:54
  been taken by telescopes, not on Earth,
• 29:57
  but um in one case on the surface of
• 29:59
  Mars, but but also from Mars orbit. Uh
• 30:04
  and there's a little bit of a story to
• 30:06
  this because these images were taken um
• 30:09
  when uh the interstellar comet Three
• 30:13
  Atlas uh made its closest passage next
• 30:18
  close closest flyby of Mars basically uh
• 30:20
  30 million kilometers of Mars. That's
• 30:23
  quite a close approach compared with the
• 30:25
  distances that we we are from from it on
• 30:28
  Earth. Uh and that took place actually
• 30:31
  nearly two months ago. uh in early
• 30:34
  October. Um but what's held up the
• 30:36
  release of the uh of the images is the
• 30:40
  um US government shutdown which
• 30:43
  prevented these images being the world.
• 30:47
  >> Spoke about that at length
• 30:49
  previous episode. So yeah, I think
• 30:51
  pretty we're pretty well squared away on
• 30:53
  the issue. Um but he had colleagues that
• 30:56
  were so badly affected by that because
• 30:59
  >> the um you know well basically no income
• 31:02
  for as long as the shutdown existed.
• 31:04
  It's very very difficult situation but
• 31:07
  >> yes so we we we know why NASA couldn't
• 31:09
  do anything at the time.
• 31:11
  >> Yeah. So so that's right. So um but we
• 31:15
  now have these images revealed now that
• 31:17
  things are up and running again. And it
• 31:19
  perhaps the the best one has come from
• 31:22
  the um high-rise camera on board Mars
• 31:26
  Reconnaissance Orbiter. Uh and that's
• 31:28
  quite a detailed image of comet 3i Atlas
• 31:32
  with its a short tail and its coma.
• 31:35
  That's the region around the nucleus
• 31:37
  where material is outgassing and and
• 31:41
  shining because of exitation by the sun.
• 31:44
  Um the there there's some interesting
• 31:47
  images from uh from the Maven uh
• 31:51
  spacecraft as well which uh has cameras
• 31:54
  on looking in the ultraviolet and in
• 31:56
  fact it's got a spectrometer on that
• 31:57
  allows you to uh split the light up into
• 32:00
  its component colors. Uh so we see the
• 32:03
  glow of hydrogen actually from uh from
• 32:06
  three Atlas uh photographed by the Maven
• 32:09
  spectra uh spec spacecraft cameras and
• 32:12
  the mast cam uh camera on the uh it's
• 32:17
  mass cam zed it's called on perseverance
• 32:20
  on the surface of Mars actually managed
• 32:22
  to capture a very very faint image uh of
• 32:26
  uh of three eye atlas against a
• 32:28
  background of stars. It's faint because
• 32:30
  that cam, mass cam, was never designed
• 32:33
  to do astronomy. It's all designed to
• 32:36
  navigate on the surface of Mars, but yet
• 32:38
  it's managed to catch a picture uh by
• 32:41
  being pointed upwards obviously uh at um
• 32:43
  at this celestial visitor. So the the
• 32:46
  hope is that as these images are
• 32:48
  analyzed, Andrew, we'll find out more
• 32:50
  about threei Atlas, maybe even to get a
• 32:53
  good measurement of how big its nucleus
• 32:55
  is, the the icy component that gives
• 32:57
  rise to all this all this luminosity. Um
• 33:01
  the last I heard was that the thinking
• 33:03
  was it was in the region of 20
• 33:05
  kilometers across, which is large for a
• 33:06
  comet nucleus. Uh but I think the jury
• 33:09
  is probably still out on that. Um might
• 33:11
  find more from these measurements. So,
• 33:13
  how much longer will ThreeI Atlas be in
• 33:16
  our vicinity?
• 33:18
  >> Uh, no, no, quite a while. Uh, it's not,
• 33:21
  you know, it's it's it's um I think it
• 33:24
  passes closest to Earth this month if I
• 33:27
  remember rightly. Um, and then we'll be
• 33:29
  receding. Uh, it has passed its closest
• 33:32
  to the sun and so it it certainly
• 33:34
  brightened up when it did that, which is
• 33:35
  what you expect. uh as it as it leaves
• 33:38
  the solar system, we'll continue to
• 33:40
  track it with the world's big
• 33:42
  telescopes. Probably the James Web will
• 33:44
  have a few more looks at it. Uh and so
• 33:46
  um I think we're we're going to be
• 33:48
  observing it for several months yet.
• 33:51
  >> Very good. All right. Yeah, it keeps
• 33:52
  making the news and uh I mean it's it's
• 33:55
  one of those things like this it's only
• 33:58
  one of a handful of these things that
• 34:00
  we've we've found, but it's starting to
• 34:03
  look like this is not an uncommon
• 34:04
  thread.
• 34:06
  That's right. And I think once again
• 34:08
  harking back to the Ver Rubin telescope,
• 34:10
  we're going to find more of these uh
• 34:12
  when that telescope comes online. We're
• 34:14
  probably going to have, you know, we've
• 34:15
  got three known interstellar objects
• 34:18
  now. It'll probably be 20 by middle of
• 34:20
  next year. Who knows? It'll be quite
• 34:23
  extraordinary
• 34:24
  >> indeed. All right. Uh you can read more
• 34:26
  about the uh the images that have been
• 34:29
  taken of three Atlas and you can see
• 34:30
  them too at the univertoday.com
• 34:34
  website. Uh Fred, that brings us to the
• 34:37
  end. Thank you so much.
• 34:39
  >> It's been a pleasure, Andrew. I amum uh
• 34:42
  I've forgotten how much I miss uh my
• 34:44
  weekly dose of space knots. So it's good
• 34:46
  to be talking again.
• 34:48
  >> It's good to have you back. Thank you
• 34:49
  for Thank you for deciding to return.
• 34:52
  >> [laughter]
• 34:53
  >> Yes,
• 34:53
  >> even without the red carpet. Oh, and by
• 34:56
  the way, that golfer I played with
• 34:57
  today, Piper Stubs from Melbourne, Piper
• 35:00
  Stubs. Look up her name.
• 35:01
  >> She uh she studied um at college in the
• 35:05
  United States and played collegiate golf
• 35:06
  over there.
• 35:07
  >> Very good.
• 35:08
  >> Uh she's finished now and she um
• 35:10
  qualified as a in political science. So,
• 35:14
  >> yeah. Uh quite a bright young lady. Uh,
• 35:18
  and um, thanks to Hugh in the studio,
• 35:20
  although he couldn't be with us today
• 35:21
  because he heard there were 40,000 near
• 35:23
  Earth asteroids discovered, so he built
• 35:25
  himself a bunker. He won't come out. And
• 35:29
  um,
• 35:30
  and by the way, uh, if you would like to
• 35:33
  become a patron, uh, by all means, jump
• 35:35
  on our website and and, uh, find out all
• 35:38
  about it. Uh, I know it's there are
• 35:40
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• 35:42
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• 35:47
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• 35:54
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• 36:01
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• 36:07
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• 36:10
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• 36:12
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• 36:20
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• 36:22
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• 36:24
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• 36:27
  That's it for this episode. Join us
• 36:28
  again soon when we do a Q&A episode. Um
• 36:32
  and and looking forward to having you
• 36:34
  join us then from me, Andrew Dunley.
• 36:36
  Until next time, bye-bye.
• 36:38
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• 36:41
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• 36:43
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