Latest / Space Nuts: Astronomy Insights & Cosmic Discoveries / Asteroids, Comets & the Latest from the DART Mission: A Cosmic Update

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Asteroids, Comets & the Latest from the DART Mission: A Cosmic Update · Space Nuts: Astronomy Insights & Cosmic Discoveries

• 0:00
  Speaker 1: Hello again, and thank you for joining us on Space Nuts,
• 0:03
  Speaker 1: the astronomy and space science podcast and radio show on
• 0:07
  Speaker 1: community radio across Australia. My name is Andrew Dunkley. Great
• 0:11
  Speaker 1: to have your company in this the six hundred and
• 0:13
  Speaker 1: seventh episode of our program Can You Believe It? And
• 0:17
  Speaker 1: this one is one hundred percent dedicated to comets and
• 0:20
  Speaker 1: asteroids in one way or another. We've got an update
• 0:23
  Speaker 1: on the potential impact of asteroid.
• 0:25
  Speaker 2: Why are four with the Moon?
• 0:28
  Speaker 1: They've been keeping an eye on this and they've come
• 0:30
  Speaker 1: up with an answer and it's it's really clever the
• 0:32
  Speaker 1: way they've done it. More news out of the Dart mission.
• 0:36
  Speaker 1: Something else has happened there. Yes, it's on a collision
• 0:38
  Speaker 1: course with nothing. Had you worry there for a moment?
• 0:41
  Speaker 1: And three I Atlas is chemically unstable. In fact, it's
• 0:46
  Speaker 1: falling down drunk. We'll tell you why on this episode
• 0:49
  Speaker 1: of Space Nuts fifteen sec Channel ten nine Ignition, Space
• 0:57
  Speaker 1: Nuts SI two Space Nurse as Can I Report It?
• 1:05
  Speaker 3: Nels?
• 1:05
  Speaker 1: Good joining us again for another stint on this little
• 1:10
  Speaker 1: podcast of ours is Professor Fred Watts, an astronomer at last.
• 1:14
  Speaker 4: Hello, Fred, Allou Andrew and it's nice to talk to you.
• 1:18
  Speaker 2: What a surprise to see you.
• 1:22
  Speaker 1: Now we have got a real rock and program today.
• 1:27
  Speaker 3: Oh I love it.
• 1:28
  Speaker 1: It's all about rocks and ice and asteroids and something
• 1:32
  Speaker 1: else which we'll get too later that's not rock and ice.
• 1:36
  Speaker 1: But first, an update on the potential impact of asteroid
• 1:40
  Speaker 1: Why Are four with the moon. They were a little
• 1:44
  Speaker 1: bit worried that it's chances of hitting the moon were well,
• 1:47
  Speaker 1: I think I heard in the early stages it's discovery,
• 1:50
  Speaker 1: the people were quoting twenty or thirty percent chance of
• 1:53
  Speaker 1: it hitting the moon. That kind of got wound back
• 1:56
  Speaker 1: to a more reasonable number. But now they've got definitive
• 2:01
  Speaker 1: evidence of what's going to happen.
• 2:05
  Speaker 3: That's correct. I mean, it's not just the moon that
• 2:10
  Speaker 3: worried us for a while with asteroid twenty twenty four
• 2:14
  Speaker 3: YR four, because when it was discovered back in twenty
• 2:18
  Speaker 3: twenty four, as you might guess, Why Are four, when
• 2:23
  Speaker 3: its trajectory was analyzed and IVE got to remember that
• 2:28
  Speaker 3: an object is only sixty meters across, which is flying
• 2:32
  Speaker 3: through space. You make observations of its position, and if
• 2:37
  Speaker 3: you've only observed it over a short period of period
• 2:39
  Speaker 3: of time, the uncertainties in its weld. Both its past
• 2:44
  Speaker 3: orbit and its future orbit are very large. So it's
• 2:47
  Speaker 3: what we call the arc, the arc of observation. The
• 2:50
  Speaker 3: wider the arc of observations that you can make, the
• 2:53
  Speaker 3: more accurate is going to be your assessment of where
• 2:56
  Speaker 3: it's come from and where it's going. And so those
• 3:00
  Speaker 3: early assessments, actually they were in early twenty twenty five
• 3:05
  Speaker 3: when these calculations were made, but it did suggest a
• 3:09
  Speaker 3: small chance that it might hit the Earth, and that
• 3:12
  Speaker 3: was very quickly. I mean, I think I'm sure you
• 3:14
  Speaker 3: and I talked about this on space.
• 3:15
  Speaker 2: Yeah, we did.
• 3:16
  Speaker 3: It was very quickly ruled out. But as it sort
• 3:21
  Speaker 3: of wandered on its way early in twenty twenty five,
• 3:26
  Speaker 3: there was still a possibility that it might hit the Moon,
• 3:31
  Speaker 3: and the time that it would happen would be twenty
• 3:36
  Speaker 3: thirty five was basically the targeted time for Sorry, no,
• 3:42
  Speaker 3: is that right?
• 3:44
  Speaker 2: Twenty thirty two? Thirty two?
• 3:46
  Speaker 3: Yeah, yeah, that's correct. Sorry, I'm mixing up my numbers.
• 3:50
  Speaker 3: You deserve when you get to a certain age. Twenty
• 3:54
  Speaker 3: thirty two, there was a non zero chance that it
• 3:59
  Speaker 3: would hit the Moon, and the story what happened then was,
• 4:04
  Speaker 3: of course this object is. It's what we call a
• 4:07
  Speaker 3: near Earth asteroid because it approaches near the Earth, but
• 4:10
  Speaker 3: it's not near the Earth all the time. Most of
• 4:12
  Speaker 3: the time, it's a long way away as it goes
• 4:14
  Speaker 3: around in its orbit around the Sun. And it sort
• 4:18
  Speaker 3: of disappeared from view essentially, certainly from the purview of
• 4:23
  Speaker 3: ground based telescopes. There was not going to be any
• 4:26
  Speaker 3: way we thought of observing it again until twenty twenty eight,
• 4:31
  Speaker 3: when it would make another close approach, not one that
• 4:33
  Speaker 3: had any risk attached to it. But we didn't expect
• 4:37
  Speaker 3: to be able to see its position in any detail
• 4:40
  Speaker 3: until twenty twenty eight, which we would need in order
• 4:43
  Speaker 3: to predict where it might be in twenty thirty two,
• 4:46
  Speaker 3: whether it's going to hit the Moon or not. But
• 4:50
  Speaker 3: there are some scientists at who use the James Webb
• 4:54
  Speaker 3: Space Telescope who tend not to let faintness stand in
• 4:59
  Speaker 3: their way, because that's why you couldn't observe this object.
• 5:02
  Speaker 3: It was just too faint and sure enough, earlier this
• 5:05
  Speaker 3: year a last month in fact, they've made two sets
• 5:08
  Speaker 3: of observations where they've actually picked up.
• 5:11
  Speaker 4: The image a tiny faint image of.
• 5:15
  Speaker 3: Twenty twenty four yr four they've picked it up and
• 5:19
  Speaker 3: allowed them the calculations to basically take those new positions,
• 5:26
  Speaker 3: the twenty twenty six positions into the orbit calculation, and
• 5:31
  Speaker 3: what they've done is they've ruled out any possibility of
• 5:35
  Speaker 3: it hitting the Moon. So that's an unexpected story for us.
• 5:40
  Speaker 3: I didn't think we'll be talking about this again until
• 5:41
  Speaker 3: twenty twenty eight, but no, we've talked about it in
• 5:44
  Speaker 3: twenty twenty six, and the web telescope has come to rescue.
• 5:48
  Speaker 3: Some people are disappointed andrew an asteroid hitting the Moon,
• 5:53
  Speaker 3: especially if you know when it's going to happen, and
• 5:55
  Speaker 3: you would know where it was going to happen as well,
• 5:58
  Speaker 3: could have produced some quite interesting pyrotechnics. It would allow spectroscopy,
• 6:04
  Speaker 3: which would tell you a little bit about the asteroid's
• 6:06
  Speaker 3: makeup as well as the makeup of the lunar regulars
• 6:09
  Speaker 3: and lunar terrain that it's smashed into. But that's not
• 6:13
  Speaker 3: going to happen. And so for anybody like astronauts who
• 6:17
  Speaker 3: might happen to be hanging about on the Moon in
• 6:19
  Speaker 3: twenty thirty two, and they may well be both Chinese
• 6:22
  Speaker 3: teycher notes and Western astronauts on.
• 6:25
  Speaker 4: The moon by then that will be a great relief.
• 6:29
  Speaker 1: I'm sure, yes, yes, you don't really want a mission
• 6:32
  Speaker 1: interrupted by a piece of look and ice. What would
• 6:37
  Speaker 1: could you if it did hit the moon? Let's just
• 6:40
  Speaker 1: play that hard at the moment and you were looking
• 6:43
  Speaker 1: at it at the time, would you actually say it
• 6:45
  Speaker 1: with the naked eye or with the telescope?
• 6:47
  Speaker 3: I don't think you would with the naked eye, but
• 6:49
  Speaker 3: you certainly would with telescopes, and even maybe a relatively
• 6:52
  Speaker 3: small telescope. We've known, I mean, certainly since the nineteen
• 6:57
  Speaker 3: fifties that rocks do hit the moon, and often these
• 7:03
  Speaker 3: are ones that are much smaller than the sixty meters
• 7:06
  Speaker 3: of Yr four. It's for a long time. I remember,
• 7:12
  Speaker 3: you know, when I was first getting into astronomy in
• 7:14
  Speaker 3: the nineteen fifties that people talked, and in particular Patrick
• 7:19
  Speaker 3: Moore talked about these what were called TLS transient lunar events,
• 7:25
  Speaker 3: and there were flashes basically that amateur astronomers kept reporting
• 7:29
  Speaker 3: said every so often there'll be something, you know, they'd
• 7:32
  Speaker 3: be looking at the Moon through a telescope and suddenly
• 7:34
  Speaker 3: there'd be a flash. And for a long time it
• 7:38
  Speaker 3: was not shut not known really whether this was due
• 7:41
  Speaker 3: to some sort of residual volcanic activity on the Moon
• 7:45
  Speaker 3: or whether it was impact of asteroids and large meteor meteorites.
• 7:50
  Speaker 3: And it was really once we'd seen the Apollo results
• 7:55
  Speaker 3: and got to know the Moon a lot better because
• 7:57
  Speaker 3: of the Apollo missions, that it was deemed to be
• 8:01
  Speaker 3: impacts that caused these transient lunar events. And so it
• 8:05
  Speaker 3: would certainly be a sixty meter object hitting the Moon
• 8:08
  Speaker 3: is quite significant, and that I don't think it will
• 8:12
  Speaker 3: be naked eye visibility, but you probably wouldn't need that
• 8:16
  Speaker 3: big a telescope to be able to see it. So yeah,
• 8:19
  Speaker 3: so interesting, especially you know, sorry, especially if you could
• 8:23
  Speaker 3: predict when and where it was going to happen. You'd
• 8:25
  Speaker 3: have all the amateur astronomers in the world on that
• 8:28
  Speaker 3: side of the Earth a seems a moon with their
• 8:31
  Speaker 3: eyes glued to the telescope.
• 8:33
  Speaker 1: Yeah, now just need you probably do explain how this works.
• 8:39
  Speaker 1: But the scientists using the James Web took images eight
• 8:44
  Speaker 1: days apart. Is that that's obviously significant because then they
• 8:49
  Speaker 1: get a straight line observation.
• 8:52
  Speaker 2: Is that how it works?
• 8:54
  Speaker 3: No, what happens is in fact what even just one
• 8:58
  Speaker 3: of those observations would have been invaluable. Two is devastatingly invaluable.
• 9:04
  Speaker 3: It makes it, you know, it increases your accuracy even
• 9:07
  Speaker 3: more because what they do they combine those new observations
• 9:13
  Speaker 3: with what we knew from its orbit the last when
• 9:17
  Speaker 3: we observed it in twenty twenty four twenty five. So
• 9:21
  Speaker 3: what you've suddenly got is you've you know, the arc
• 9:24
  Speaker 3: of observation might just have been a few months at
• 9:26
  Speaker 3: the end of twenty twenty four early twenty twenty five.
• 9:29
  Speaker 3: Now what you've done is you've extended that arc by
• 9:32
  Speaker 3: a year effectively, and that gives you a much much
• 9:37
  Speaker 3: more accurate value of what we call its orbital elements.
• 9:44
  Speaker 3: The asteroid is its orbit is actually delineated by six numbers,
• 9:51
  Speaker 3: and those are the orbital elements, as they're called. Those
• 9:54
  Speaker 3: numbers get more accurate the more the longer you can
• 9:59
  Speaker 3: observe it for. So and it's not just that how
• 10:02
  Speaker 3: long you can observe it for, it's the interval between,
• 10:05
  Speaker 3: you know, what's the interval of time between the observations,
• 10:08
  Speaker 3: which is what we've got here. We've suddenly got observations
• 10:11
  Speaker 3: made a year later. It's it's absolutely narrowed down the
• 10:14
  Speaker 3: uncertainties in the in the orbital elements, and so what
• 10:18
  Speaker 3: we can then do is another great word. From those
• 10:21
  Speaker 3: orbital elements, we can generate what's called an ephemeris, and
• 10:24
  Speaker 3: the femurist tells you where the asteroid is going to be.
• 10:27
  Speaker 3: It's a future predictions. That was what my MSc was on,
• 10:31
  Speaker 3: making orbital elements and fMRI ds with of asteroids with
• 10:37
  Speaker 3: a really new invention called computers. Yes, it's I think
• 10:43
  Speaker 3: there'll be a big hit. Well that'd be hopefully not
• 10:48
  Speaker 3: depending where you're standing. It was certainly I told you
• 10:51
  Speaker 3: it was a big hit with the with the External Examiner,
• 10:54
  Speaker 3: a gentleman in Glasgow University by the name of Archie Roy.
• 10:57
  Speaker 4: He said, this work should be pop people should belt
• 11:01
  Speaker 4: I read about this.
• 11:03
  Speaker 3: It never was. But the one copy is actually behind me.
• 11:09
  Speaker 3: It's one of the two thick volumes at the end.
• 11:11
  Speaker 3: The others my PhD thesis.
• 11:13
  Speaker 1: I keep thinking of questions while we talk about this,
• 11:17
  Speaker 1: But what I find extraordinary is that the James Webspace
• 11:20
  Speaker 1: Telescope was trying to find something sixty meters in size
• 11:25
  Speaker 1: from a distance of forty eight million kilometers thirty million
• 11:29
  Speaker 1: miles YEP and it founded twice.
• 11:31
  Speaker 3: It's pretty fantastic, isn't it. It would just pop above
• 11:35
  Speaker 3: the background noise. You know, when you're doing these observations,
• 11:39
  Speaker 3: you've got various sources of what we call noise, which
• 11:42
  Speaker 3: is basically uncertainty, and these are probably very close to
• 11:48
  Speaker 3: that noise level. But it's just shown up enough that
• 11:51
  Speaker 3: gives them what they call what we call a three
• 11:53
  Speaker 3: sigma certainty. It's you know, that's a level of certainty
• 11:57
  Speaker 3: that you need. It's just a technical term for the
• 11:58
  Speaker 3: statistical analysis that's being used.
• 12:02
  Speaker 4: Maybe they got help from AI as well.
• 12:04
  Speaker 1: Maybe, Yeah, it's possible. I have a doomsday question though. Great,
• 12:11
  Speaker 1: and we're going to talk about the Dark Mission next
• 12:14
  Speaker 1: because there's new information about that deflection test. But when
• 12:18
  Speaker 1: do you intervene? Like if we left it a couple
• 12:22
  Speaker 1: of years because James Webb couldn't find it and then
• 12:26
  Speaker 1: we realized it was going to hit Earth or something
• 12:28
  Speaker 1: to that effect, when is it too late to we divene?
• 12:32
  Speaker 3: It's with an asteroid like that, it's almost too late
• 12:37
  Speaker 3: already because you've only got so if we'd observed this
• 12:40
  Speaker 3: in twenty twenty eight and the probability of an impact
• 12:43
  Speaker 3: with Earth had gone up. I mean that disappeared long ago,
• 12:47
  Speaker 3: so it's not a problem. But if that happened, you've
• 12:50
  Speaker 3: only got four years, and we're not ready quite yet
• 12:57
  Speaker 3: to mount an emergency mission. I think down the track
• 13:00
  Speaker 3: we will be, having seen what's come out the story,
• 13:03
  Speaker 3: we're going to do next tent. I think down the
• 13:06
  Speaker 3: track we will have probably planetary defense rockets and spacecraft
• 13:12
  Speaker 3: almost ready to go, so that you could think about
• 13:16
  Speaker 3: deflecting an object if it looked as though it was
• 13:18
  Speaker 3: going to impact the Earth. But I suspect with four years,
• 13:22
  Speaker 3: that's not very long for a modified orbit to evolve
• 13:25
  Speaker 3: into one that will miss the planet altogether. I think
• 13:30
  Speaker 3: what would happen would be you'd mobilize civil defense resources
• 13:37
  Speaker 3: because you'd probably quite quickly get an idea where the
• 13:40
  Speaker 3: collision was going to be. You'd have a circle of uncertainty,
• 13:43
  Speaker 3: but you would know roughly where it was, which side
• 13:46
  Speaker 3: of the planet was going to be facing it. And
• 13:49
  Speaker 3: a sixty meter object, I mean, it's probably twice the
• 13:54
  Speaker 3: size of what exploded over Chellyabinsk in twenty thirteen, and
• 13:59
  Speaker 3: we know that that caused structural damage when the shockwave
• 14:03
  Speaker 3: hit the ground from thirty kilometers high, and it was
• 14:07
  Speaker 3: the broken glass that caused all the injuries. Nobody died,
• 14:11
  Speaker 3: but people.
• 14:12
  Speaker 2: Did get injured.
• 14:13
  Speaker 3: And if you knew something like that was going to happen,
• 14:16
  Speaker 3: then you'd get the people out or get them in
• 14:19
  Speaker 3: bunkers or whatever, because that would be the most likely scenario.
• 14:23
  Speaker 3: And air burst it may be what happened at Tunguska.
• 14:26
  Speaker 2: Actually, yes, there's been.
• 14:29
  Speaker 3: Yeah.
• 14:31
  Speaker 1: I think the latest theory is it was actually a
• 14:33
  Speaker 1: atmospheric graze rather than an impact in the course explosion downwards. Yeah,
• 14:40
  Speaker 1: radiating out. The images from that are incredible. It can
• 14:44
  Speaker 1: look them up all the trees. Yeah, just flattened. Unbelievable. Yeah.
• 14:49
  Speaker 1: If you would like to read about the latest observations
• 14:52
  Speaker 1: regarding asteroid twenty twenty four yr two, you can go
• 14:56
  Speaker 1: to the science blog dot com website, or you can
• 14:58
  Speaker 1: go to the ESET website where that publish the findings.
• 15:02
  Speaker 1: There's a space Nuts with Andrew Dunkley and Professor Fred Watson.
• 15:06
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• 16:39
  Speaker 3: I believe that this nation should commit itself.
• 16:43
  Speaker 1: Were chieving the goal before this decade is out of
• 16:47
  Speaker 1: landing a man on the Moon and returning him safely
• 16:49
  Speaker 1: to the Europeece Nuts, Well, we said we talk about it,
• 16:53
  Speaker 1: and we're going to talk about it the Dart mission.
• 16:56
  Speaker 1: I think we should start by kind of just revisiting
• 16:59
  Speaker 1: what that mission was all about and why, well, we
• 17:02
  Speaker 1: know why, to see if we could move something that
• 17:05
  Speaker 1: may hit Earth one day off a bit so that
• 17:08
  Speaker 1: it missed us. I probably just explained it. But yeah,
• 17:12
  Speaker 1: this was four years ago, wasn't it, Fred.
• 17:15
  Speaker 3: Indeed it was, that's right, twenty twenty two, it was.
• 17:18
  Speaker 3: I think it was its September. I can't remember the question,
• 17:22
  Speaker 3: but I think it's about then. So a really really
• 17:27
  Speaker 3: clever experiment conducted by NASA and a team of project scientists.
• 17:34
  Speaker 3: What do you do to test whether you can move
• 17:37
  Speaker 3: an asteroid? What you don't do is slap something into
• 17:41
  Speaker 3: an asteroid and see whether you can change its orbit
• 17:44
  Speaker 3: around the Sun. And that's because the orbits of planets,
• 17:49
  Speaker 3: asteroids and comets actually as well, are very very stable.
• 17:53
  Speaker 3: It's quite hard to change them because you're talking about,
• 17:57
  Speaker 3: you know, lots of rather large forces, gravitational forces and
• 18:02
  Speaker 3: things like that. So what they did was they said Okay,
• 18:05
  Speaker 3: we won't do that. What we'll do is we'll find
• 18:07
  Speaker 3: an asteroid with a moon, and we now know there
• 18:10
  Speaker 3: are a lot of those, and they chose an asteroid
• 18:13
  Speaker 3: called Didimos, if I remember rightly, about half a kilometer across,
• 18:17
  Speaker 3: which had a little moon called Dimorphos, which is about
• 18:22
  Speaker 3: I think one hundred and seventy meters. Is a figure
• 18:24
  Speaker 3: that comes to mind, this little moon that goes around
• 18:27
  Speaker 3: Didimos once in I've got a feeling remembering it is
• 18:30
  Speaker 3: about eleven hours it's orbital period. So you smash something
• 18:33
  Speaker 3: into the little asteroid moon, and what you then look
• 18:39
  Speaker 3: for is how the orbit of the moon around its
• 18:42
  Speaker 3: parent body, in other words, the orbit of Dimorphos around Didimos,
• 18:47
  Speaker 3: how that changes, Because something on that scale is much
• 18:50
  Speaker 3: easier to change than the orbit of an asteroid around
• 18:53
  Speaker 3: the Sun. And as we all know, it was incredibly successful.
• 18:58
  Speaker 3: The orbit of the orbital period of Dimorphous I think
• 19:03
  Speaker 3: it was reduced by was it thirty three minutes? I
• 19:05
  Speaker 3: think was the figure if I remember rightly, the Dart
• 19:10
  Speaker 3: spacecraft and remembering these numbers from the last time we
• 19:13
  Speaker 3: talked about it, Andrew, I think it was three tons.
• 19:18
  Speaker 3: I think thereabouts. Hit dimorphous at six kilometers per second
• 19:24
  Speaker 3: caused a huge plume of data, sorry, a huge plume
• 19:27
  Speaker 3: of debris. Not data, lots of data as well, but
• 19:30
  Speaker 3: debris two. And that was all in fact visible from
• 19:35
  Speaker 3: Earth as well as from things like the Hubble space telescope.
• 19:39
  Speaker 3: So it was an experiment that was well devised, well
• 19:44
  Speaker 3: set up, and had excellent results. It did exactly it
• 19:47
  Speaker 3: Actually it did better than what the mission scientist hoped.
• 19:51
  Speaker 3: And the reason why it did better was because there
• 19:54
  Speaker 3: was a much bigger effect. When you hit something at
• 19:57
  Speaker 3: six kilometers per second. Everything's vapor the surface that you hit,
• 20:02
  Speaker 3: which is actually a rubble pile, but the surface he
• 20:04
  Speaker 3: hits vaporized, as is the spacecraft itself, and that vapor
• 20:08
  Speaker 3: acts like a rocket exhaust. So it's not just the
• 20:11
  Speaker 3: nudge that you get from knocking something weighing three tons
• 20:14
  Speaker 3: into an asteroid. It's also the sort of exhaust effect
• 20:18
  Speaker 3: that comes from that as well. So it and that
• 20:24
  Speaker 3: was what was very hard to quantify. We didn't really
• 20:27
  Speaker 3: know what that would be, but it was enough to
• 20:29
  Speaker 3: make a significant difference. So that's the backstory.
• 20:32
  Speaker 2: Andrew, Yes, then you were right.
• 20:33
  Speaker 1: It was the twenty sixth of September twenty twenty two. Okay, great, yeah.
• 20:38
  Speaker 3: Yeah, if you want to just check the of the
• 20:42
  Speaker 3: dark impact while you're looking there, so correct if I've
• 20:46
  Speaker 3: said it wrong. I said three tons, but I might
• 20:48
  Speaker 3: be wrong.
• 20:48
  Speaker 1: I can't someone I'll do that, But I guess we
• 20:52
  Speaker 1: could move on to what's actually happened now they've done
• 20:55
  Speaker 1: a more analysis and something spectacular has happened as a
• 20:59
  Speaker 1: contract that event three and a half years.
• 21:02
  Speaker 3: Ago, and the way it's happened is neat as well,
• 21:05
  Speaker 3: because what you're looking for, if you're looking at the
• 21:10
  Speaker 3: way an asteroid change an asteroid orbit changes, you're looking
• 21:14
  Speaker 3: for incredible precision in space.
• 21:18
  Speaker 4: And there are limits as to how.
• 21:20
  Speaker 3: Precise we can get those measurements using telescopes. It's all
• 21:25
  Speaker 3: about the position in space of the object. Telescopes are
• 21:28
  Speaker 3: great at that, of course, but there is a better
• 21:32
  Speaker 3: way for asteroids, and that is to use ocultations. And
• 21:37
  Speaker 3: an ocultation is when an object like an asteroid passes
• 21:41
  Speaker 3: in front of a star and you can predict this
• 21:45
  Speaker 3: is going to happen. So what you do is for
• 21:48
  Speaker 3: an object that's only one hundred and seventy meters across,
• 21:52
  Speaker 3: which is the size of Dimorphous you've got. What you
• 21:58
  Speaker 3: do is your space astronomers along a line who are
• 22:02
  Speaker 3: observing and because you're not quite sure where the shadow
• 22:07
  Speaker 3: of the asteroid cast in the light of the star
• 22:10
  Speaker 3: is going to fall. But with telescopes, what you can
• 22:13
  Speaker 3: do is you can see the dip in a star's
• 22:15
  Speaker 3: light as the asteroid passes in front of it. It's
• 22:17
  Speaker 3: what we call an ocultation. And if you've got enough
• 22:20
  Speaker 3: observers on the ground, it gives you a much higher
• 22:23
  Speaker 3: level of precision as to where in the sky that
• 22:26
  Speaker 3: asteroid is. And so that process was carried out I
• 22:31
  Speaker 3: think last year, and so that means that you've suddenly
• 22:36
  Speaker 3: got very very accurate measurements of the position not just
• 22:41
  Speaker 3: of Dimorphis itself, but also the parent asteroid Didimos. In fact,
• 22:45
  Speaker 3: I think you might be Didimos that was used for
• 22:48
  Speaker 3: the occultation. And so the bottom line is that low
• 22:55
  Speaker 3: and behold, it didn't just the impact didn't just change
• 22:59
  Speaker 3: the orbit of Dimorphous around Dilimos. It changed the orbit
• 23:03
  Speaker 3: of the whole system, the pair of them around the Sun.
• 23:07
  Speaker 3: And that is the first time one of the nice
• 23:10
  Speaker 3: quotes in one of these articles. It's the first time
• 23:13
  Speaker 3: a human made object has measurably altered the path of
• 23:16
  Speaker 3: a celestial body around the Sun. That's in a NASA statement.
• 23:20
  Speaker 2: That is incredible.
• 23:21
  Speaker 1: And of course the obvious question is now, will we
• 23:25
  Speaker 1: be able to track where it will go versus where
• 23:27
  Speaker 1: it would have gone?
• 23:29
  Speaker 3: Yes, And indeed that's already sort of already happening, because
• 23:33
  Speaker 3: there'll be further observations. And it's the same as we
• 23:36
  Speaker 3: were just talking about in regard to Yr four. The
• 23:39
  Speaker 3: longer the arc of observations you've got, the more accurate
• 23:42
  Speaker 3: your knowledge of its orbit.
• 23:44
  Speaker 4: Now the changing orbit is not much.
• 23:49
  Speaker 3: I can't remember how many days I've got the paper
• 23:53
  Speaker 3: in front of me. Actually, the main paper, it doesn't
• 23:58
  Speaker 3: actually give us the orbit little period of the pair
• 24:01
  Speaker 3: around the Sun, but they've changed that orbital period by
• 24:05
  Speaker 3: wait for its point one five of a second. So
• 24:09
  Speaker 3: it's very I mean, it's a matter of you know,
• 24:11
  Speaker 3: it's it's these two orbit between the between the orbits
• 24:16
  Speaker 3: of Mars and Jupiter, the part of the main asteroid belt.
• 24:19
  Speaker 3: So their orbital periods are probably measured in sort of
• 24:23
  Speaker 3: thousands of days or at least high numbers of hundreds
• 24:26
  Speaker 3: of days, and to change that by zero point one
• 24:29
  Speaker 3: five of a second is not very much. It speaks
• 24:33
  Speaker 3: wonders for the volumes, for the accuracy with which the
• 24:36
  Speaker 3: orbit has been determined. But it's look, it's it's it happened.
• 24:41
  Speaker 3: It has actually happened that we've changed the orbit of
• 24:44
  Speaker 3: an asteroid by hitting it, or hitting its little moon,
• 24:48
  Speaker 3: in fact, by with a with a massive object. Did
• 24:52
  Speaker 3: you manage to find out how much it weighed?
• 24:54
  Speaker 1: Six hundred and ten kilograms, Okay, so that's weigh one
• 24:57
  Speaker 1: hundred and forty pounds. Yeah, so it's less than a
• 25:00
  Speaker 1: ton half a ton. Yeah, I apologize for three tons.
• 25:04
  Speaker 1: That was the number from something else. I reckon if
• 25:07
  Speaker 1: they if they could have got three tons up there,
• 25:08
  Speaker 1: they would have used it, they would have done.
• 25:10
  Speaker 3: Yeah, but that makes it even more spectacular. You know,
• 25:13
  Speaker 3: something weighing less than a car clouting the moon of
• 25:18
  Speaker 3: an asteroid can change the orbit of that asteroid and
• 25:21
  Speaker 3: its parent body, just too very quickly. Since we're talking
• 25:26
  Speaker 3: to an educated, an arandie audience here, the mechanism by
• 25:30
  Speaker 3: which that changed is so you think, well, you've hit
• 25:33
  Speaker 3: the you've hit the moon, asteroid. How does that change
• 25:37
  Speaker 3: the orbit of the parent asteroid and what it does?
• 25:40
  Speaker 3: Hitting the moon asteroid gives you a slight change in
• 25:43
  Speaker 3: the position of the Barry center, and that's the center
• 25:46
  Speaker 3: of mass of the two objects, their center of gravity combined,
• 25:51
  Speaker 3: and it's that that has changed its orbit. It's the
• 25:54
  Speaker 3: Barry center, which of course includes both of the objects.
• 25:57
  Speaker 3: The Barry center is representative of both didimos and dimorphous
• 26:01
  Speaker 3: because it's the center of mass between them. So changing
• 26:04
  Speaker 3: the position of the Barry center or the orbit of
• 26:06
  Speaker 3: the Barry Center essentially changes the orbit of the asteroid,
• 26:10
  Speaker 3: which means that would something like that threatening the Earth,
• 26:14
  Speaker 3: and you had enough enough years down the track for
• 26:17
  Speaker 3: its orbit to evolve so that it would miss the Earth.
• 26:20
  Speaker 3: That might be a way to do it.
• 26:22
  Speaker 1: Yeah. I know a few people named Barry and they
• 26:24
  Speaker 1: always wanting to be the center of attencing.
• 26:29
  Speaker 2: It's had to cup, didn't it. Yeah, it did.
• 26:33
  Speaker 1: It's a great story, it's great read. You can pick
• 26:35
  Speaker 1: it up on the NASA website or you can go
• 26:38
  Speaker 1: to fizz dot org. Phys I got to do that
• 26:43
  Speaker 1: from now on because somebody came to us one day
• 26:46
  Speaker 1: and said, I can't find this fi double z dot
• 26:49
  Speaker 1: org because it's not it's fizz pH y s. Yes,
• 26:54
  Speaker 1: but it's great news out of that experiment.
• 26:57
  Speaker 2: Three and a half.
• 26:58
  Speaker 1: Years post event, This is space nuts. Andrew Dugley with
• 27:02
  Speaker 1: Professor Fred Watson withpen anguality they plant space nuts. Now
• 27:12
  Speaker 1: to another piece of rock that has been getting a
• 27:17
  Speaker 1: lot of attention in recent times. Three I Atlas, the
• 27:20
  Speaker 1: XO comet or exo asteroid. Is it a comet or
• 27:23
  Speaker 1: an asteroid thread comet?
• 27:25
  Speaker 2: Comet?
• 27:25
  Speaker 1: Yeah, yeah, it appears that it's it's very different from
• 27:29
  Speaker 1: anything we've seen before, to the point where it's raging
• 27:32
  Speaker 1: through our solar systems stone drunk off its face, not quite,
• 27:38
  Speaker 1: but its chemical makeup is just way out of kilter
• 27:42
  Speaker 1: with what we would have expected.
• 27:45
  Speaker 3: That's right, So you know, this is three Eye Atlas
• 27:48
  Speaker 3: is definitely the gift that keeps from giving because what
• 27:53
  Speaker 3: we've got is a free sample from another solar system
• 27:56
  Speaker 3: that is careering through our own solar system and enough
• 28:00
  Speaker 3: for our telescopes to get details of it. It's now
• 28:03
  Speaker 3: actually receding from Earth and from the Sun, but it's
• 28:09
  Speaker 3: still producing gases from its icy surface. It behaves exactly
• 28:14
  Speaker 3: like a comet. Wood from our own solar system gets
• 28:18
  Speaker 3: near the Sun, the ice is basically turn into gas directly.
• 28:23
  Speaker 3: This subly matate, and what then happens is we can
• 28:28
  Speaker 3: sense what gases are there, what chemical compounds are there
• 28:33
  Speaker 3: by looking at the spectrum of what we call the
• 28:36
  Speaker 3: coma of the comet. That's the fuzzy area around it
• 28:39
  Speaker 3: that's caused by all this out gasing material. And so
• 28:42
  Speaker 3: Comet three I Atlas has recently been the subject of
• 28:47
  Speaker 3: probably the world's most powerful, well certainly the world's most
• 28:50
  Speaker 3: powerful millimeter wave radio telescope, the array in the high
• 28:55
  Speaker 3: country of the Atta Karma, the Alma telescope, the Atta
• 28:59
  Speaker 3: Karma La milimeter submilimeter array at about five thousand meters high,
• 29:05
  Speaker 3: not very far from San Pedro de Atacama. And when
• 29:08
  Speaker 3: I went to try and get in their back door
• 29:11
  Speaker 3: one time, I nearly died because the air was so thin,
• 29:15
  Speaker 3: and we didn't get in the back door either. So
• 29:19
  Speaker 3: never mind, Alma is fabulous telescope. So what's the story Alma,
• 29:26
  Speaker 3: which is run by various different organizations. But the scientists
• 29:32
  Speaker 3: who have been observing three Eye Atlas with it have
• 29:36
  Speaker 3: looked at the fingerprints the spectral fingerprints of two molecules.
• 29:41
  Speaker 3: One is methanol, which is a type of alcohol, and
• 29:45
  Speaker 3: the other is hydrogen cyanide HCN. It's an organic molecule
• 29:50
  Speaker 3: very common in comets. So both of those are found
• 29:55
  Speaker 3: in comets in the Solar System. But what is the
• 29:58
  Speaker 3: surprise the amount of methanol. It's as ther NRAO National
• 30:06
  Speaker 3: Radio Astronomy Observatory press release says three I Atlas is
• 30:11
  Speaker 3: heavily enriched in methanol compared to hydrogen cyanide, far beyond
• 30:16
  Speaker 3: what is typically seen in comets born in our own
• 30:19
  Speaker 3: solar system.
• 30:20
  Speaker 2: You know what it is for it wait for it.
• 30:24
  Speaker 2: You're gonna love this one. It's inroxinated.
• 30:28
  Speaker 4: Well, oh, yes, I'll go with that.
• 30:34
  Speaker 2: I know. I just invented a new word what he did.
• 30:37
  Speaker 3: Yes, And you probably need to be reasonably androxinated in
• 30:40
  Speaker 3: order to invent it.
• 30:43
  Speaker 1: And it's so early, yes, so earlier in the day.
• 30:46
  Speaker 3: That's right. Anyway, the observing team just coming back to
• 30:51
  Speaker 3: a state of reality, perfect sobriety. It's methanolter to hydrogen
• 30:59
  Speaker 3: cyanide ration of between seventy and one hundred and twenty,
• 31:04
  Speaker 3: which means it's among the most methanol rich comets ever discovered.
• 31:11
  Speaker 3: There's been a few in the Solar system that have
• 31:14
  Speaker 3: got high levels of methanol, but this is, you know,
• 31:17
  Speaker 3: it's up there on the extreme end of this distribution
• 31:23
  Speaker 3: and familiar. I'll just read from the very nice National
• 31:26
  Speaker 3: Radiostronomy Observatory press release on this, which says, these measurements
• 31:32
  Speaker 3: imply that the ic material from three I Atlas was
• 31:35
  Speaker 3: formed by or experienced very different conditions from those that
• 31:41
  Speaker 3: shape most comets in our own solar system. Previous work
• 31:45
  Speaker 3: with the James Web Space telescope has shown that three
• 31:47
  Speaker 3: Eye Atlas had a coma dominated by carbon dioxide when
• 31:51
  Speaker 3: it was far from the Sun, and these new Alma
• 31:54
  Speaker 3: results add methanol as another unusual detail in its chemical
• 31:58
  Speaker 3: inventory in nice paragraph, so it is unusual. It's an
• 32:03
  Speaker 3: object that shows all the characteristics of a comet, but
• 32:07
  Speaker 3: we're seeing all the extremes and maybe that shouldn't surprise
• 32:11
  Speaker 3: us because we do know it has come from somewhere else.
• 32:15
  Speaker 1: Which tromps the question, does that mean where it's come
• 32:18
  Speaker 1: from might be quite different to our.
• 32:22
  Speaker 3: Yeah, it's yes, that's right. It could you know, it
• 32:24
  Speaker 3: would certainly lead credibility to any idea that chemical ratios
• 32:31
  Speaker 3: within other solar systems are not necessarily what we find
• 32:35
  Speaker 3: here in our own solar system. In other words, you know,
• 32:39
  Speaker 3: there could be quite different chemistry going on, particularly in
• 32:42
  Speaker 3: the early history of those solar systems. We think a
• 32:44
  Speaker 3: lot of these compounds like methanol and hydrogen cyanide, we
• 32:49
  Speaker 3: think a lot of these are formed very early in
• 32:52
  Speaker 3: the history of a solar system in the cold of space, molecules,
• 32:56
  Speaker 3: atoms combined together to form molecules, and we know that
• 33:00
  Speaker 3: there is a very, very rich chemistry out there, which
• 33:04
  Speaker 3: was kind of unexpected really. I mean, when I was
• 33:07
  Speaker 3: a young astronomer, we thought always in terms of just elements,
• 33:11
  Speaker 3: the elements that we can see in the atmospheres of stars, hydrogen, carbon, calcium, iron,
• 33:17
  Speaker 3: all of those. But now such a lot of what
• 33:19
  Speaker 3: we do with the you know, with the arsenal of
• 33:24
  Speaker 3: wonderful astronomical instruments that we have today, we can look
• 33:27
  Speaker 3: at the chemistry of these things, the actual chemical reactions
• 33:31
  Speaker 3: that go on in the laboratory of deep space.
• 33:35
  Speaker 2: Yeah.
• 33:35
  Speaker 1: Something you don't know about Fred is he's been in
• 33:37
  Speaker 1: astronomy so long that he got in trouble at school
• 33:40
  Speaker 1: once for throwing an apple at Isaac Newton. So true story.
• 33:45
  Speaker 4: Yeah, yeah, yeah, yeah, yeah I got the cane for that.
• 33:48
  Speaker 2: Yeah.
• 33:49
  Speaker 1: I got the cain a lot at school too, but
• 33:50
  Speaker 1: not for throwing apples. I did throw out a sandwich
• 33:53
  Speaker 1: at a teacher once, but yeah, I was egg gone
• 33:55
  Speaker 1: to do that, and I felt for it was exactly
• 33:59
  Speaker 1: and I can't remember was on Probably something hideous that
• 34:01
  Speaker 1: I ate when I was a kid.
• 34:03
  Speaker 3: If you're egged on, it must have been in it.
• 34:05
  Speaker 1: Yeah, it was a very silly move and I'll always
• 34:09
  Speaker 1: regret it. Okay, So if you want to read about
• 34:12
  Speaker 1: that what constitutes a rather drunk rock in space, you
• 34:17
  Speaker 1: can go to the National Radio Observatory website where they've
• 34:21
  Speaker 1: published their findings. And Fred, that brings us to the end.
• 34:25
  Speaker 2: Thank you so very much. It's a great pleasure.
• 34:27
  Speaker 3: Andrew. Always good to chat, and we'll see you again
• 34:30
  Speaker 3: next time.
• 34:31
  Speaker 2: We will on a Q and A edition.
• 34:33
  Speaker 1: Fred Watson, Professor Fred Watson, Astronomer at Large, joining us
• 34:37
  Speaker 1: every week twice a week in fact, for space nuts.
• 34:41
  Speaker 1: And if you would like to visit our website, please
• 34:43
  Speaker 1: do one thing we could use for our Q and
• 34:46
  Speaker 1: A episodes audio questions. We are desperately short of them.
• 34:49
  Speaker 1: There's some weird quirk at the beginning of every year
• 34:53
  Speaker 1: they dry up, and we don't know why that is
• 34:55
  Speaker 1: an anomaly, but it is a thing. But if you
• 34:59
  Speaker 1: go to our webs site space Nuts podcast dot com
• 35:02
  Speaker 1: and click on the ask Me Anything tab at the top,
• 35:04
  Speaker 1: it's just labeled AMA, you can send us your questions
• 35:07
  Speaker 1: or comments. We welcome them. Don't forget to tell us
• 35:10
  Speaker 1: who you are and where you're from. And thanks to
• 35:12
  Speaker 1: Hu in the studio who couldn't be with us today
• 35:15
  Speaker 1: because he went out on a bender last night and
• 35:17
  Speaker 1: got inoxicated. Bomb boom and from me, from me Andrew Dunkley,
• 35:22
  Speaker 1: thanks for your company. See on the next episode of
• 35:24
  Speaker 1: Space Nuts. Bye byepauts.
• 35:27
  Speaker 2: You'll be listening to the Space Nuts podcast.
• 35:31
  Speaker 1: Available at Apple Podcasts, Spotify, iHeartRadio, or your favorite podcast player.
• 35:37
  Speaker 2: You can also stream on demand at bides dot com.
• 35:41
  Speaker 1: This has been another quality podcast production from nights dot com.