Latest / Space Nuts: Astronomy Insights & Cosmic Discoveries / Theia's Fate, Galaxy Mergers & the Mysteries of Mars' Atmosphere | Q&A

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Theia's Fate, Galaxy Mergers & the Mysteries of Mars' Atmosphere | Q&A · Space Nuts: Astronomy Insights & Cosmic Discoveries

• 0:00
  Speaker 1: Hello again, thanks for joining us on a Q and
• 0:03
  Speaker 1: a edition of Space Nuts. My name is Andrew Dunkley,
• 0:06
  Speaker 1: and today we will be I won't Fred will be
• 0:09
  Speaker 1: answering questions about the former planet known as Fear Galaxy.
• 0:16
  Speaker 1: Mergers have come up. We go back to Mars with
• 0:20
  Speaker 1: a theory about Olympus mons and why only hydrogen? That
• 0:26
  Speaker 1: is a question that comes from a believer, a five
• 0:30
  Speaker 1: year old. We'll deal with all of that today on
• 0:32
  Speaker 1: this edition of Space Nuts fifteen in channel ten nine
• 0:39
  Speaker 1: ignition sequence Space nuts or three two space nuts as
• 0:48
  Speaker 1: can I reported Neil Goods. And to solve all of
• 0:52
  Speaker 1: those little riddles, we're joined again by Professor Fred Watson,
• 0:55
  Speaker 1: Astronomer at Large.
• 0:56
  Speaker 2: Hello Fred, Hello Andrew, very good to see you again.
• 1:00
  Speaker 1: Good to see you too. We've got a bit of
• 1:03
  Speaker 1: weird noise on your line. I think it's probably just
• 1:06
  Speaker 1: the Internet being the Internet, so hopefully that'll go away.
• 1:09
  Speaker 1: In fact, it just did, so yeah, there you go,
• 1:11
  Speaker 1: solved itself. It must have heard me winging all as well.
• 1:16
  Speaker 1: I assume.
• 1:17
  Speaker 2: Yep, we're doing fine. Thank you. It's good to join
• 1:20
  Speaker 2: you on the questions episode of what's this called again?
• 1:24
  Speaker 2: Oh Space Nuts?
• 1:25
  Speaker 1: That's right, space idiots, space nuts. Yes, yeah, they're all
• 1:29
  Speaker 1: good people. We might as well jump in straight away
• 1:33
  Speaker 1: to our first question, and it comes from one of
• 1:37
  Speaker 1: our regular contributors.
• 1:38
  Speaker 3: It's Rusty today, Fred and Andrew, It's Rusty in Donnybrook.
• 1:43
  Speaker 3: I've been listening to your latest episode where look at
• 1:49
  Speaker 3: the relationship between Sea and the Earth before the collision,
• 1:56
  Speaker 3: and I just want to make sure I've got the
• 1:59
  Speaker 3: story glory straight, so I put it in my own words.
• 2:03
  Speaker 3: The Earth had a buddy named THEA who came a
• 2:07
  Speaker 3: little too near. She hit with a splash, then made
• 2:12
  Speaker 3: off with a dash. But there's no mooning for THEA
• 2:17
  Speaker 3: around here, So what happened to THEA after the collision?
• 2:22
  Speaker 3: The theories prior to this revelation said THEA had enough
• 2:27
  Speaker 3: kinetic energy to leave the Solar System all together.
• 2:31
  Speaker 1: But if the orbits were so close, that doesn't seem likely.
• 2:34
  Speaker 3: So it seems to me there's three possibilities that THEA
• 2:40
  Speaker 3: fell into the Sun, which would be another amazing feat
• 2:45
  Speaker 3: to get that sort of precision. After the collision, Sea
• 2:50
  Speaker 3: picked up a little slingshot energy and moved out further
• 2:55
  Speaker 3: and became Mars, and Mars is a Mars size object
• 3:00
  Speaker 3: after all. And the third possibility I can think of
• 3:04
  Speaker 3: is that it picked up an unlikely amount of kinetic
• 3:08
  Speaker 3: energy and became planet nine. So if it did become
• 3:15
  Speaker 3: planet nine, it would have a highly eccentric orbit because
• 3:20
  Speaker 3: it's too far away from us to actually see at
• 3:23
  Speaker 3: the moment. But would this orbit then at some stage
• 3:29
  Speaker 3: bring it back to the Inner Solar System of its origin?
• 3:35
  Speaker 1: That's it? How you guys? Well, jeez, thanks, Rusty, hope
• 3:39
  Speaker 1: you're will two over there in w A. What happened
• 3:43
  Speaker 1: to THEA? He's come up with some interesting theories, quite
• 3:46
  Speaker 1: a few ideas. I'm guessing they can't all be true.
• 3:52
  Speaker 2: I think that's right. There's actually a fourth possibility I
• 3:58
  Speaker 2: did to the three that that Rusty has proposed, and
• 4:04
  Speaker 2: I think that's the one that's usually accepted, and there's
• 4:07
  Speaker 2: kind of evidence for that. The fourth possibility is that
• 4:12
  Speaker 2: basically was absorbed into the Earth. The remnants of thear
• 4:17
  Speaker 2: actually in the Earth's mantle, And in fact, there's something
• 4:26
  Speaker 2: called and there are two of these, a large low
• 4:30
  Speaker 2: sheer velocity province in the Earth's lower mantle. And the
• 4:36
  Speaker 2: hypothesis is that that is the remnants of thear so
• 4:41
  Speaker 2: that we still see the evidence of that collision by
• 4:44
  Speaker 2: anomalies basically in the Earth's mantle, which we investigate, you know,
• 4:51
  Speaker 2: with seismology. That's how we know about what's going on
• 4:54
  Speaker 2: in the mantle of the Earth. It's how we know
• 4:56
  Speaker 2: about large low sheer velocity provinces. I'm kind of just
• 5:01
  Speaker 2: using the words here because I'm not somebody who knows
• 5:04
  Speaker 2: about the inside of the planet other than you know,
• 5:08
  Speaker 2: the sketchiest outline of a core, a mantle, and a crust.
• 5:13
  Speaker 2: But the mantle we know has significant structure and in
• 5:17
  Speaker 2: fact money. And I have a good friend who Nick Petford,
• 5:23
  Speaker 2: who is a volcanologist, and he's somebody who looks at
• 5:26
  Speaker 2: these velocity structures in the in the mantle of the
• 5:31
  Speaker 2: Earth and you know, the upwelling of material to form
• 5:36
  Speaker 2: volcanoes and things like that. Next time we see Nick,
• 5:39
  Speaker 2: I will ask him about these large scale low velocity
• 5:42
  Speaker 2: shear areas and their relationship to THEA. But I think
• 5:47
  Speaker 2: that's the consensus, rusty that the impact basically resulted in
• 5:55
  Speaker 2: an explosion which shed something like I think one of
• 6:01
  Speaker 2: the suggestions is about seventy percent of the mass of
• 6:07
  Speaker 2: the Moon may have come from THEA. I'm actually I
• 6:14
  Speaker 2: think that might. Let's put it this way, THEA is
• 6:19
  Speaker 2: responsible for seventy to ninety percent of the total mass
• 6:23
  Speaker 2: of the Moon. Under the classic giant impact scenario, where
• 6:28
  Speaker 2: THEA is considerably smaller than a proto Earth, which it
• 6:31
  Speaker 2: would have been, the Earth was still kind of Earthish sized.
• 6:35
  Speaker 2: THEA was Mars ish sized, but the Earth would have
• 6:39
  Speaker 2: probably grown a bit by absorbing the debris from THEA.
• 6:44
  Speaker 2: Remember that the mass of the Moon is about one
• 6:46
  Speaker 2: eightieth of the mass of the Earth, so it's a
• 6:50
  Speaker 2: significantly large body compared with the other moons in the
• 6:52
  Speaker 2: Solar System, but it's clearly smaller than you know, it's
• 6:58
  Speaker 2: not Mars sized, And so Rusty's right in that the
• 7:03
  Speaker 2: you know, the remnants of THEAR had to do something,
• 7:06
  Speaker 2: but the current theory is that they were absorbed by
• 7:09
  Speaker 2: the proto Earth, and we can still see evidence for them.
• 7:12
  Speaker 1: Yeah, okay, so yeah, definitely not likely to be P nine.
• 7:19
  Speaker 1: That would be a very odd kind of occurrence, wouldn't it.
• 7:25
  Speaker 2: Yeah, well, yes, I think that kinematics don't work. You
• 7:31
  Speaker 2: you know, you can't give it enough velocity and you
• 7:34
  Speaker 2: need you need a lot of velocity for it to
• 7:36
  Speaker 2: fall back into the Sun as well, too much energy.
• 7:39
  Speaker 2: That's quite an energetic process, is getting rid of the
• 7:43
  Speaker 2: orbital velocity of a body to make it fall into
• 7:46
  Speaker 2: the sub It's you know, you need as much energy
• 7:48
  Speaker 2: as you do to get it pushed out to the
• 7:51
  Speaker 2: outer planet.
• 7:52
  Speaker 1: So, yeah, didn't we talk about it once before and
• 7:56
  Speaker 1: suggest that remnants of it just probably speed off into
• 7:58
  Speaker 1: space never to be So again.
• 8:00
  Speaker 2: I'm sure there would have been an element of that. Yes,
• 8:04
  Speaker 2: you know that that debris cloud that eventually formed the
• 8:06
  Speaker 2: Moon probably lost some of its some of its material content,
• 8:11
  Speaker 2: and there may even be stuff wandering around in the
• 8:15
  Speaker 2: form of neuroth asteroids now that are bits and pieces
• 8:18
  Speaker 2: that are left over from that. But remember this was
• 8:20
  Speaker 2: you know, this was within the first couple of hundred
• 8:23
  Speaker 2: million years of the history of the Solar System. So
• 8:27
  Speaker 2: you're talking about things that happened a very long time ago. Yeah.
• 8:31
  Speaker 1: Indeed, I'm wondering, Fred, why we've just got this sudden
• 8:36
  Speaker 1: influx of people asking questions in POM. This is just
• 8:41
  Speaker 1: I'm blaming Martin for that. Martin Berman Gorvine, you started
• 8:46
  Speaker 1: this and now it's so I think.
• 8:50
  Speaker 2: I really liked Rusty's one there about the thought that
• 8:53
  Speaker 2: was very nice.
• 8:54
  Speaker 1: Yeah, I don't know. I think he pushed it a
• 8:55
  Speaker 1: bit on one of those one of those rhymes. Although
• 8:59
  Speaker 1: there there was a regular guest, and I'm sure you
• 9:01
  Speaker 1: know who I'm talking about, col Wilson, who used to
• 9:03
  Speaker 1: join us on the radio once a week to do
• 9:05
  Speaker 1: bush poetry, Blew the Shearer, and he often got asked
• 9:10
  Speaker 1: to do shearing demonstrations and he had to tell them, look,
• 9:12
  Speaker 1: I'm not a shearer. I can't the sheer a sheep
• 9:14
  Speaker 1: that saved my life. It's just my show name. But
• 9:18
  Speaker 1: he used to actually invent words to create rhymes. It
• 9:24
  Speaker 1: was one of his wonderful traits. And yeah, I used
• 9:29
  Speaker 1: to spend a lot of time with Collie as a
• 9:30
  Speaker 1: terrific bloke. I think we've dealt with Rusties theories and
• 9:35
  Speaker 1: they were all wrong. Thanks for Rusty. Takes Rusty great
• 9:40
  Speaker 1: to hear from you. Let's take a break from the
• 9:44
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• 11:18
  Speaker 1: to our next question, and this one I've lost here
• 11:21
  Speaker 1: it is. This comes from Lena. I am a new
• 11:24
  Speaker 1: listener and not as hardcore as Spacenut as most of
• 11:28
  Speaker 1: your audience. It's probably a good thing, but I saw
• 11:31
  Speaker 1: an article today talking about merging spiral galaxies. If the
• 11:36
  Speaker 1: universe is expanding, how does something as large as a
• 11:39
  Speaker 1: galaxy move toward and merge with another galaxy? It seems
• 11:43
  Speaker 1: they should be moving further away from each other. That
• 11:46
  Speaker 1: comes from Lena in British Columbia in Canada. I think
• 11:52
  Speaker 1: we've had questions of this ilk before, but it's always
• 11:55
  Speaker 1: good to go over it again because there's a lot
• 11:58
  Speaker 1: more going on in the universe than just you know,
• 12:01
  Speaker 1: spreading out like school children playing what's that game where
• 12:04
  Speaker 1: you don't know, I don't know what you call it?
• 12:08
  Speaker 1: Something that you throw a ball and try and hit
• 12:09
  Speaker 1: someone in the head. Anyway, go on, that's cricket, isn't it? Dodgeball? Dodgeball?
• 12:17
  Speaker 1: And there's a bunch of games like that, like Red
• 12:21
  Speaker 1: Rover Crossover. Did you ever play that? Oh no, we
• 12:25
  Speaker 1: mustill have a lot of fun with that.
• 12:29
  Speaker 2: Anyway. Look, Lina's question is a great one, and I
• 12:32
  Speaker 2: guess the simplest answer here is that, yes, galaxies are big,
• 12:38
  Speaker 2: but they're tiny compared with the universe, And so the
• 12:43
  Speaker 2: expansion of the universe is something that we look at
• 12:46
  Speaker 2: on very large scales. You know, you're looking out billions
• 12:50
  Speaker 2: of light years and seeing this expansion. It's actually, with
• 12:56
  Speaker 2: today's technology, it's one of the easiest observations that you
• 12:58
  Speaker 2: can make that the universe is expanding, discovered back in
• 13:03
  Speaker 2: nineteen twenty nine by Edwin Hubble. So, yes, So if
• 13:07
  Speaker 2: the universe is expanding in space, is getting bigger and
• 13:10
  Speaker 2: naturally carrying things further and further apart, why are some
• 13:14
  Speaker 2: galaxies coming towards each other? And it's because on the
• 13:16
  Speaker 2: scale of a galaxy, the expansion of the universe is miniscule,
• 13:22
  Speaker 2: and that by far the dominant the dominant process is gravity.
• 13:27
  Speaker 2: So galaxies, which yes, are being carried gradually apart by
• 13:34
  Speaker 2: the expansion of the universe, when you put them close together,
• 13:38
  Speaker 2: their own gravity gives them a force that pulls them
• 13:40
  Speaker 2: together that's much greater than the expansion. And we actually
• 13:46
  Speaker 2: give that a name. We call this the peculiar velocities
• 13:50
  Speaker 2: of galaxies, because it's a velocity peculiar to an individual galaxy.
• 13:54
  Speaker 2: And the usual way that we describe it, and I
• 13:56
  Speaker 2: think we've talked about this before on Space Nuts, is
• 14:00
  Speaker 2: if you imagine a river flowing, which represents the kind
• 14:06
  Speaker 2: of expansion of the universe, and then somebody in a
• 14:08
  Speaker 2: boat is moving around on the river. They're being carried
• 14:11
  Speaker 2: downstream by the river's movement, but they've got their own
• 14:14
  Speaker 2: movement provided by the boat on the water. And it's
• 14:18
  Speaker 2: a bit like that with galaxies. They're being carried along
• 14:20
  Speaker 2: by the expansion of the universe, but a far bigger
• 14:23
  Speaker 2: effect is the way gravity pulls them together. So that's
• 14:27
  Speaker 2: what's pulling our galaxy and the Andromeda galaxy together. It's
• 14:31
  Speaker 2: the gravitational force between them. And on the scale of
• 14:35
  Speaker 2: the distance between Andromeda and our own galaxy, which is
• 14:39
  Speaker 2: about two and a half million light years, the expansion
• 14:42
  Speaker 2: of the universe makes virtually no difference. You only start
• 14:45
  Speaker 2: really noticing it when you get to much bigger, bigger scales.
• 14:49
  Speaker 1: Yeah, they will come a point in time where all
• 14:52
  Speaker 1: these galaxy mergers will finished, They'll be done and dusted,
• 14:56
  Speaker 1: and the universe will keep expanding and eventually it'll just
• 15:00
  Speaker 1: be darkness. There'll be nothing.
• 15:03
  Speaker 2: Yeah. If that's assuming dark aage big crunch, right, yeah,
• 15:09
  Speaker 2: I mean dark energy. We're now just starting to see
• 15:11
  Speaker 2: the first signs that maybe over the last few billion
• 15:14
  Speaker 2: years it's decreased. And so the acceleration of the universe
• 15:19
  Speaker 2: it's still accelerating. The expansion is still getting faster, but
• 15:23
  Speaker 2: it's getting faster at a slower rate, if I put
• 15:26
  Speaker 2: it that way. So the acceleration itself looks as though
• 15:29
  Speaker 2: it's declining. And that's why some people are still talking
• 15:32
  Speaker 2: about the big crunch or they're going to have gibb again.
• 15:36
  Speaker 2: It's it's because if the acceleration eventually goes away and
• 15:40
  Speaker 2: becomes a deceleration, then yeah, you're going to get a
• 15:42
  Speaker 2: big crunch.
• 15:43
  Speaker 1: Yeah, yeah, it's you know, could go either way at
• 15:47
  Speaker 1: this stage the way they're talking. We we have witnessed
• 15:52
  Speaker 1: some galaxy e mergers, haven't we. It doesn't. Our own
• 15:54
  Speaker 1: galaxy actually contain a couple of other galaxies that have
• 15:58
  Speaker 1: been sucked into our void.
• 16:00
  Speaker 2: Yeah, two quite big ones. Actually, what the things we
• 16:03
  Speaker 2: call the large and small Madrilanic clouds. They are satellite
• 16:08
  Speaker 2: galaxies of our own and they're being stripped of their
• 16:10
  Speaker 2: stars by our own galaxy. It's gravitational pull and will
• 16:15
  Speaker 2: eventually be part of the halo of our own galaxy.
• 16:18
  Speaker 2: But we see we also see examples in deep space
• 16:22
  Speaker 2: of big galaxies actually merging. The most famous is the
• 16:26
  Speaker 2: Antenna Galaxies, two galaxies which are merging and pulling off
• 16:31
  Speaker 2: spiral arms off each other.
• 16:33
  Speaker 1: Quite it all happens in slow motion, though, doesn't it.
• 16:38
  Speaker 1: And and when people, you know, think about galaxy merger merges,
• 16:43
  Speaker 1: they're thinking all this drama and collisions and generally doesn't
• 16:48
  Speaker 1: turn out that way.
• 16:49
  Speaker 2: Well, you're talking about processes that take millions of years,
• 16:52
  Speaker 2: and yeah, and you know it's and and in fact,
• 16:57
  Speaker 2: galaxies probably when they collide, you don't get stars actually
• 17:01
  Speaker 2: colliding because there's so much space between the stars. But
• 17:03
  Speaker 2: what you get is the effect of clouds of gas colliding,
• 17:07
  Speaker 2: and that spawns new star formation, so you might get
• 17:10
  Speaker 2: lots of hot young stars being born in a galaxy collision.
• 17:14
  Speaker 1: All right, here's my horrible attempt at poetry. It's more
• 17:17
  Speaker 1: of a dance than a glance.
• 17:20
  Speaker 2: I like that.
• 17:21
  Speaker 1: Yeah, yeah it is.
• 17:22
  Speaker 2: Actually that's exactly what it is.
• 17:24
  Speaker 1: Yeah, there we go. All right. I hope that answers
• 17:27
  Speaker 1: your question. Lena, Thanks for sending it in and thanks
• 17:30
  Speaker 1: for listening to Space Nuts, which is what you're doing
• 17:33
  Speaker 1: right now with Andrew Dunkley and Professor Fred Watson.
• 17:38
  Speaker 2: We choose to go to the moon and this decay
• 17:41
  Speaker 2: and do the other thing not because they are easy,
• 17:45
  Speaker 2: but because.
• 17:45
  Speaker 1: They are hard, these nuts. Our next question comes from Kevin,
• 17:53
  Speaker 1: and he said, I've been listening with much learning and
• 17:55
  Speaker 1: enjoyment to all the previous podcasts. I'm about halfway through them,
• 18:00
  Speaker 1: so he's at around two hundred and nearly three hundred,
• 18:02
  Speaker 1: I imagine, so let's just wait for him to catch up.
• 18:08
  Speaker 1: He says, your discussions of Mars and its lack of
• 18:12
  Speaker 1: atmosphere made me wonder if perhaps what must have been
• 18:16
  Speaker 1: an enormous eruption of Olympus Olympus Mons is what might
• 18:20
  Speaker 1: have killed the planet, or at least its atmosphere. That
• 18:23
  Speaker 1: comes from Kevin, So, yeah, I'm very impressed by Olympus
• 18:30
  Speaker 1: Monds because it is the biggest volcano in the Solar System,
• 18:34
  Speaker 1: and it's staggeringly huge. But could an Olympus Mons eruption
• 18:42
  Speaker 1: have stripped the atmosphere of Mars?
• 18:47
  Speaker 2: Probably not, the I mean the eruptions of Olympus Mons
• 18:53
  Speaker 2: would certainly have sent a lot of gas into the atmosphere.
• 19:00
  Speaker 2: Olympus Mons has probably taken a long long time to grow.
• 19:04
  Speaker 2: It's you know, it will have had eruptions kind of
• 19:09
  Speaker 2: like some of the bigger volcanoes on Earth, and they
• 19:12
  Speaker 2: took a long long time, so it's not like one
• 19:15
  Speaker 2: big explosion. And that's why Olympus Mons is so high.
• 19:20
  Speaker 2: It's because it's over a hot spot in Mars's mantle
• 19:23
  Speaker 2: that just keeps on pushing out material, or did for
• 19:27
  Speaker 2: a long period of time, and without the plate tectonics
• 19:30
  Speaker 2: that carry the surface crossed over the hot spot and
• 19:34
  Speaker 2: results in a chain of volcanoes like we see in Hawaii.
• 19:37
  Speaker 2: It all built this one big volcano. So it's a
• 19:41
  Speaker 2: process that took a long time, and maybe it did
• 19:44
  Speaker 2: play a role in the changes in Mars's atmosphere. But
• 19:49
  Speaker 2: we think the main reason why Mars lost its atmosphere
• 19:53
  Speaker 2: is because it is a world that is too small
• 19:57
  Speaker 2: to sustain plate tectonics. It doesn't have a magnetic field,
• 20:01
  Speaker 2: so the subatomic particles from the Sun bombard the atmosphere continuously,
• 20:05
  Speaker 2: and we think that's one of the main reasons why
• 20:08
  Speaker 2: why it eventually lost lost its atmosphere. I mean, it's
• 20:11
  Speaker 2: not most altogether. It's still got zero point six of
• 20:14
  Speaker 2: a percent of the Earth's atmospheric pressure at the surface.
• 20:16
  Speaker 2: That's enough for winds to blow and you know, to
• 20:20
  Speaker 2: sort of blow dust clouds onto solar panels of spacecraft
• 20:23
  Speaker 2: and things of that sort. But it's certainly not an
• 20:26
  Speaker 2: atmosphere that we would recognize as being similar to Earth's.
• 20:30
  Speaker 2: So I think, I think it's a good question. Actually,
• 20:33
  Speaker 2: I think Olympus Mons and the neighboring volcanoes, there's there's
• 20:38
  Speaker 2: more than one big volcano, the Olympus Mons is the biggest.
• 20:42
  Speaker 2: They probably would have affected the atmosphere of Mars, but
• 20:45
  Speaker 2: they're probably not the root cause why the atmosphere drifted
• 20:48
  Speaker 2: into space.
• 20:49
  Speaker 1: Yeah, it's more likely it was because Mars just couldn't
• 20:54
  Speaker 1: hold itself together. Basically, it didn't have the gravity.
• 21:01
  Speaker 2: It's yeah, it doesn't have the gravity to keep it
• 21:06
  Speaker 2: hot enough to sustain plate tectonics or a magnetic dynabo basically,
• 21:12
  Speaker 2: which is a magnetic field.
• 21:14
  Speaker 1: Yeah, but Olympus Mons is fascinating for a few reason,
• 21:18
  Speaker 1: So correct me if I'm wrong. But I think right now,
• 21:21
  Speaker 1: as Mars is Olympus Mon's summit actually peaks out of
• 21:26
  Speaker 1: the atmosphere. Is that right? It's sticking up that high?
• 21:29
  Speaker 2: Yeah, it's certainly. I mean the atmosphere is like Earth's atmosphere.
• 21:34
  Speaker 2: It gradually disappears as you go higher. But yeah, I
• 21:39
  Speaker 2: mean effectively the summit is the pressure will be considerably
• 21:42
  Speaker 2: lower there than it is delm what you might call
• 21:45
  Speaker 2: the surface of Mars.
• 21:46
  Speaker 1: This is one honking big shield volcano, though, isn't it
• 21:50
  Speaker 1: like twenty one point two eighty seven kilometers in height
• 21:55
  Speaker 1: thirteen point two miles or sixty and forty feet. Someone's
• 22:01
  Speaker 1: going to climb that one day and stick a flag
• 22:04
  Speaker 1: in it. It's two and a half times the elevation
• 22:07
  Speaker 1: of Mount Everest. And this is something about Mars that
• 22:10
  Speaker 1: astounds me. It's a smaller planet, but all its features
• 22:13
  Speaker 1: geographically just make ours look like tidley wings. And it
• 22:19
  Speaker 1: span is six hundred kilometers six hundred kilometers wide.
• 22:24
  Speaker 2: Yep, that's that's extra.
• 22:25
  Speaker 1: I just can't imagine it. I'd love to be able
• 22:28
  Speaker 1: to stand there and have a look in my last
• 22:30
  Speaker 1: five seconds of life, because I didn't take my breathing apparatus.
• 22:34
  Speaker 1: But it is an amazing world.
• 22:38
  Speaker 2: It's got cliffs as well around its base which are
• 22:41
  Speaker 2: pretty spectacular. I think they're killing meters as well, so
• 22:45
  Speaker 2: you know, it's quite quite, quite an extraordinary world.
• 22:51
  Speaker 1: Yeah. Well, the Coldera itself is fifty miles across, and
• 22:55
  Speaker 1: you compare that to Kilaweo, which is like a couple
• 22:58
  Speaker 1: of miles across. It's amazing. No. I love that question,
• 23:04
  Speaker 1: and yeah, good thinking, but probably not. And it sort
• 23:07
  Speaker 1: of brings back the same argument on Earth that people
• 23:10
  Speaker 1: say our global warming is caused by volcanoes and cows.
• 23:13
  Speaker 1: It's got nothing to do with the billions of cars
• 23:16
  Speaker 1: that we're driving around every day. But I think they've
• 23:19
  Speaker 1: proven that's just not the case as far as i'm aware.
• 23:26
  Speaker 1: Thanks for your question, Kevin, lovely to hear from you.
• 23:28
  Speaker 1: Our final question comes from Yuki Hi. I'm Yuki. I
• 23:33
  Speaker 1: am five years old and I live in Canberra. We
• 23:37
  Speaker 1: listen to your podcast nearly every day. My question is
• 23:40
  Speaker 1: why is hydrogen the only element that isn't made in stars?
• 23:45
  Speaker 1: Why was hydrogen the only element around just after the
• 23:49
  Speaker 1: Big Bang and not others?
• 23:52
  Speaker 2: Yeah, that's a great question. Yeah, and congratulations to your
• 23:57
  Speaker 2: ki on being able to even think of a question.
• 24:00
  Speaker 2: Like that at the age of five, because I certainly
• 24:02
  Speaker 2: wouldn't have.
• 24:03
  Speaker 1: Been now I wouldn't either. I was still trying to
• 24:06
  Speaker 1: fix the wheel on my conquered toy.
• 24:08
  Speaker 2: Yes, that's right. I think I was at that level,
• 24:11
  Speaker 2: and that look, the the bottom line is that hydrogen
• 24:17
  Speaker 2: it was created in the aftermath of the Big Bang.
• 24:21
  Speaker 2: I think sort of three minutes after the Big Bang,
• 24:24
  Speaker 2: the temperature had cool enough that you could start to
• 24:27
  Speaker 2: form atoms. And the atom that was was produced was
• 24:34
  Speaker 2: the simplest it's one proton. It's the simplest atomic nucleus.
• 24:40
  Speaker 2: And so that was what basically condensed out of the
• 24:46
  Speaker 2: of the of the aftermath of the Big Bang. As
• 24:49
  Speaker 2: as energy became matter, you got protons forming, and hydrogen
• 24:56
  Speaker 2: is protons. In fact, in that period you also got
• 25:03
  Speaker 2: the start of the process that does produce other elements
• 25:07
  Speaker 2: in stars, what we call nuclear synthesis, where the nuclei
• 25:11
  Speaker 2: of atoms, the centers of the atoms stick together, and
• 25:16
  Speaker 2: it did. That process did start. So I think it
• 25:18
  Speaker 2: come from the percentage it's something like twenty percent. I
• 25:21
  Speaker 2: think of the aftermath of the Big Bang is helium,
• 25:24
  Speaker 2: which is the next most complex atomic nucleus, and formed
• 25:31
  Speaker 2: by hydrogen atoms coming together, but then the temperature dropped
• 25:36
  Speaker 2: far enough that you didn't get the extension of that
• 25:40
  Speaker 2: process into the formation of other atoms. So it basically
• 25:48
  Speaker 2: had to wait until stars started to form because of
• 25:53
  Speaker 2: the gravitational pull of these clouds of hydrogen together that
• 25:58
  Speaker 2: raised the temperature again enough to start forming other elements.
• 26:04
  Speaker 2: And so that's basically what it's all about. It's just
• 26:07
  Speaker 2: the simplest of atoms is the hydrogen atom. That is
• 26:10
  Speaker 2: why that was created. And you know, we nearly got
• 26:14
  Speaker 2: more elements being created in the Big Bang, but only helium.
• 26:21
  Speaker 2: Actually there's a bit of lithium and other stuff as
• 26:24
  Speaker 2: well tiny amounts of other nuclei. But it's true to
• 26:31
  Speaker 2: say that the star formations, star formation, and the interiors
• 26:36
  Speaker 2: of stars is what led to the huge array of
• 26:39
  Speaker 2: elements that we see now, all the elements of the
• 26:41
  Speaker 2: periodic table. That's a fantastic question. It is.
• 26:46
  Speaker 1: When you look at the list of the top ten
• 26:49
  Speaker 1: gases in the universe by order of concentration, hydrogen is
• 26:54
  Speaker 1: far and away the most dominant, with seventy four to
• 26:58
  Speaker 1: seventy five percent of what they did scrub is baryonic
• 27:01
  Speaker 1: mass helium at twenty four to twenty five percent, which
• 27:05
  Speaker 1: leaves almost no room for anything else. Oxygen is less
• 27:09
  Speaker 1: than one percent carbon, less than half a percent, neon,
• 27:11
  Speaker 1: less than point one and then it just dwindles away.
• 27:16
  Speaker 1: At number ten, you've got sulfur at point zero zero
• 27:19
  Speaker 1: point zero four to four percent concentrations. They're staggering numbers
• 27:27
  Speaker 1: when you're really.
• 27:28
  Speaker 2: Yeah, so you go down the list. The bottom line
• 27:31
  Speaker 2: is that the Big Bang hydrogen is still around. In fact,
• 27:35
  Speaker 2: it it makes up quite a large percentage of the
• 27:38
  Speaker 2: items in your body as well. Yeah.
• 27:42
  Speaker 1: Yeah, well it's everywhere, isn't it. And that's the bottom line.
• 27:48
  Speaker 1: And the way the Big Bang happened and everything that
• 27:52
  Speaker 1: went on afterwards, you know, one smidgy little thing didn't happen,
• 27:56
  Speaker 1: we probably wouldn't be here. Yeah, that's right. It's a
• 28:01
  Speaker 1: scary thought. But then again, there's so much we don't know.
• 28:05
  Speaker 2: U People believe in multiverses because they say, you know,
• 28:10
  Speaker 2: the conditions are exactly right for life to form in
• 28:14
  Speaker 2: our universe, and they might not have been. Yes, maybe
• 28:17
  Speaker 2: there are lots of other universes where life didn't form.
• 28:22
  Speaker 1: Well, yeah, the mathematics supports the theory, doesn't it. Oh gosh,
• 28:29
  Speaker 1: the brain hurting part of the show just happened. So anyway, Yeah,
• 28:35
  Speaker 1: it just keeps us thinking and it keeps us looking
• 28:37
  Speaker 1: for answers, and that's what it's all about. Yuki. Great
• 28:40
  Speaker 1: to hear from you, and hope all is well in Canberra.
• 28:43
  Speaker 1: And a reminder, if you would like to send us questions,
• 28:47
  Speaker 1: we welcome them with open arms. You can send them
• 28:49
  Speaker 1: through our website space nuts dot io and just click
• 28:53
  Speaker 1: on the ask Me Anything link at the top. It
• 28:55
  Speaker 1: says a M A and we will do our best.
• 28:58
  Speaker 1: Don't forget to tell us who you are and where
• 29:01
  Speaker 1: you're from, and we will put your question on if
• 29:05
  Speaker 1: we haven't had it before, and even if we have,
• 29:07
  Speaker 1: we might revisit them. We do that from time to time.
• 29:11
  Speaker 1: Keep them coming. And if you haven't asked a question
• 29:14
  Speaker 1: before and you've always wanted to, please send it in.
• 29:17
  Speaker 1: We'd love to hear from you. And we're just about done. Fred,
• 29:21
  Speaker 1: thank you very much.
• 29:23
  Speaker 2: Great pleasure. Andrew Or was good and hopefully we'll chat
• 29:27
  Speaker 2: again soon.
• 29:28
  Speaker 1: I hope, so that'll be good. Professor Fred Watson, Astronomer
• 29:31
  Speaker 1: at Large. And thanks to Hu in the studio who
• 29:33
  Speaker 1: didn't have a hydrogen problem, but he did have a
• 29:36
  Speaker 1: methane problem. But he'll be out of an emergency surgery
• 29:39
  Speaker 1: very very soon, hopefully for next week's episode. And from
• 29:41
  Speaker 1: me Andrew Dunkley, thanks for your company. Catch you on
• 29:43
  Speaker 1: the next episode of Space Nuts. Bye bye.
• 29:48
  Speaker 3: You'll be listening to the Space Nuts podcast.
• 29:52
  Speaker 1: Available at Apple Podcasts, Spotify, iHeartRadio, or your favorite podcast player.
• 29:58
  Speaker 1: You can also stream onto the at fights dot com.
• 30:01
  Speaker 1: This has been another quality podcast production from fights dot com.