Latest / Space Nuts: Astronomy Insights & Cosmic Discoveries / #470: Cosmic Questions: Dark Matter, Titan's Secrets & Universe's Energy

Transcript

#470: Cosmic Questions: Dark Matter, Titan's Secrets & Universe's Energy · Space Nuts: Astronomy Insights & Cosmic Discoveries

• 0:00
  Speaker 1: Hi there, Thanks for joining us on a Q and
• 0:02
  Speaker 1: A edition of Space Nuts. Andrew Duntley here, your Host's
• 0:05
  Speaker 1: great to have your company. In this episode, we are
• 0:07
  Speaker 1: going to talk about the universe without black holes, dark
• 0:11
  Speaker 1: matter or dark energy. What would it be like? Yeah,
• 0:15
  Speaker 1: probably completely different, mightn't exist at all, don't know. We've
• 0:19
  Speaker 1: also got a question about loss of energy and the
• 0:22
  Speaker 1: age of the universe. Another universe question, the early universe
• 0:27
  Speaker 1: and all the matter and the stars and things, and
• 0:30
  Speaker 1: why we get so surprised when we discover something that's
• 0:32
  Speaker 1: old because it's all been there from the very beginning.
• 0:35
  Speaker 1: It's a good question. And Titan's atmosphere has come up
• 0:40
  Speaker 1: from one of our audience members. So we'll answer all
• 0:42
  Speaker 1: of those questions today on Space Nuts.
• 0:46
  Speaker 2: Fifteen said in channel ten.
• 0:50
  Speaker 1: Nine ignition Space Nuts NI or three.
• 0:56
  Speaker 3: Two more red one Space Nets and I report it
• 1:01
  Speaker 3: Neils good.
• 1:02
  Speaker 1: And he's back again for more. Can't believe it. It's
• 1:05
  Speaker 1: Professor Fred Wat's an astronomer.
• 1:07
  Speaker 4: La. I can't believe it either.
• 1:11
  Speaker 1: How you doing, Andrew, Well, well, yeah, thank you, you're
• 1:15
  Speaker 1: looking well to you. In fact, I would go as
• 1:18
  Speaker 1: far as saying that since you left the public service
• 1:21
  Speaker 1: you seem a lot, you seem a lot less tense.
• 1:25
  Speaker 2: A lot.
• 1:25
  Speaker 4: How it's really interesting because I don't have to scan
• 1:31
  Speaker 4: my you know, my government laptop every morning to see
• 1:36
  Speaker 4: what meetings I've got during the day, and that makes
• 1:38
  Speaker 4: the day a lot more relaxed. I do still on
• 1:41
  Speaker 4: the meetings, but they're under a lot better control.
• 1:45
  Speaker 1: Yeah, well that's good, that's good. Shall we tackle some questions? Well,
• 1:51
  Speaker 1: let's attempt it. All right, Let's go to our first
• 1:55
  Speaker 1: one that comes from Reynold or he may pronounce it Renault.
• 2:00
  Speaker 1: How would our universe behave without black holes, dark matter,
• 2:03
  Speaker 1: and dark energy? At what phase did dark matter and
• 2:07
  Speaker 1: dark energy appear? That's a double banger. What do you
• 2:12
  Speaker 1: think for it?
• 2:14
  Speaker 4: Yeah, I think it's a profound question, and you know
• 2:17
  Speaker 4: it's at the forefront of modern day cosmology. So we
• 2:23
  Speaker 4: think that it was the dark matter that really caused
• 2:28
  Speaker 4: the ability of the universe to form galaxies, well, stars
• 2:36
  Speaker 4: and galaxies, because what we think happened was that the
• 2:41
  Speaker 4: dark matter came first and sort of coalesced into what
• 2:46
  Speaker 4: we call the cosmic web, this kind of honeycomb structure
• 2:49
  Speaker 4: of sheets of dark matter, which attracted the hydrogen that
• 2:56
  Speaker 4: that stage pervaded the universe to form a similar structure
• 3:01
  Speaker 4: because the hydrogen collapse gravitationally to sort of mimic the
• 3:06
  Speaker 4: underlying dark matter structure. And then, excuse me, during that collapse,
• 3:11
  Speaker 4: many stars were formed. Star formation took place, Galaxies formed
• 3:16
  Speaker 4: because the stars that you know, they all formed in
• 3:20
  Speaker 4: these large blobs of matter. And we see that today.
• 3:23
  Speaker 4: We still see when you look at a structure of
• 3:26
  Speaker 4: where galaxies lie in today's universe, you find that they
• 3:28
  Speaker 4: make up this honeycomb, which basically mimics what we see
• 3:33
  Speaker 4: in the cosmic microwave background radiation, which we think is
• 3:36
  Speaker 4: the precursor of those galaxies. That's the sound ways going
• 3:40
  Speaker 4: through the early universe. So we think that without dark matter,
• 3:45
  Speaker 4: the universe will be very different and wouldn't have this
• 3:48
  Speaker 4: underlying web, and maybe galaxies and stars wouldn't have formed.
• 3:52
  Speaker 4: That's really interesting. So now dark energy go ahead.
• 3:58
  Speaker 1: No, I was going to say, so if dark energy
• 4:02
  Speaker 1: was the driving force and it didn't exist, would our
• 4:07
  Speaker 1: universe have formed at all?
• 4:08
  Speaker 3: Anyway?
• 4:10
  Speaker 2: Well?
• 4:10
  Speaker 4: Yeah, dark energy is that different things? It's the.
• 4:16
  Speaker 3: Yeah.
• 4:16
  Speaker 4: So with that, yes, dark matter would think would is
• 4:20
  Speaker 4: what allowed galaxies to form out the universe itself might
• 4:23
  Speaker 4: have formed. We don't really understand the Big Bang well
• 4:27
  Speaker 4: enough to know just where it all came from, but
• 4:34
  Speaker 4: we might have had a universe devoid of dark matter,
• 4:38
  Speaker 4: just full of cold hydrogen and not really doing anything.
• 4:41
  Speaker 4: So that's pretty boring for the universe. And dark energy,
• 4:45
  Speaker 4: it really is a property of the expansion of the universe,
• 4:50
  Speaker 4: so it's set telling us that space itself has energy.
• 4:54
  Speaker 4: So I think the second part of our renal question
• 4:59
  Speaker 4: is at what phase did dark matter and dark energy appear?
• 5:03
  Speaker 4: So we think dark matter appeared right at the beginning. Now,
• 5:07
  Speaker 4: dark energy was probably always there. This is a hot
• 5:10
  Speaker 4: topic in cosmology, but we think it's only manifested itself
• 5:16
  Speaker 4: in the last five or six hundred sorry, the last
• 5:18
  Speaker 4: five or six billion years, in other words, about half
• 5:21
  Speaker 4: the age of the universe. And we think that's probably
• 5:26
  Speaker 4: because dark matter. Dark energy might have been there all
• 5:29
  Speaker 4: the time, but it didn't have enough energy to cause
• 5:34
  Speaker 4: the universe's expansion to accelerate, which is how we see
• 5:38
  Speaker 4: dark energy. It didn't have enough energy early on because
• 5:42
  Speaker 4: the galaxies and stars, the galaxies themselves were too close
• 5:46
  Speaker 4: together and their neutral gravitational pull was enough to sort
• 5:50
  Speaker 4: of slow down the dark energy and hide its effect.
• 5:54
  Speaker 4: So we think dark energy might always have been there.
• 5:58
  Speaker 4: The big question is as if evolved, because for about
• 6:02
  Speaker 4: the last twenty years, the thinking has been that it's
• 6:04
  Speaker 4: a constant that it's a property of you know, the
• 6:08
  Speaker 4: same amount of dark energy per unit volume of space
• 6:12
  Speaker 4: per cubic centimeter if your like of space. That so
• 6:17
  Speaker 4: it's said that, in other words, the dark energy is
• 6:19
  Speaker 4: proportional to the volume of space. So as the space
• 6:22
  Speaker 4: expands with the expansion of the universe, that you get
• 6:25
  Speaker 4: more dark energy. But the thinking now is that maybe
• 6:28
  Speaker 4: that's not quite true. There might be a slight evolution
• 6:31
  Speaker 4: effect over time, which is still being explored.
• 6:35
  Speaker 1: So another piece of his question was, you know, a
• 6:39
  Speaker 1: universe devoid of black holes, what would that be like?
• 6:47
  Speaker 4: Yeah, we think black holes are a natural consequence of
• 6:51
  Speaker 4: the formation of stars and galaxies. Without a universe without
• 6:56
  Speaker 4: black holes might not be that different because until forty
• 7:02
  Speaker 4: or fifty years ago, we thought the universe didn't have
• 7:04
  Speaker 4: black holes. That's true, and it's only by a lot
• 7:09
  Speaker 4: of fairly detailed and careful research that we've discovered that
• 7:12
  Speaker 4: the black holes everywhere. Yeah, So yes, that's an interesting question.
• 7:17
  Speaker 4: I don't know that the consequences there would there will
• 7:19
  Speaker 4: be a lot less high energy events going on in
• 7:22
  Speaker 4: the universe. We wouldn't see quasars for a start. Quaisars
• 7:25
  Speaker 4: are powered by black holes, the delinquent galaxies with a
• 7:27
  Speaker 4: black hole at their center.
• 7:30
  Speaker 1: HM.
• 7:31
  Speaker 3: Okay.
• 7:32
  Speaker 1: But if you didn't have any of that, in any
• 7:35
  Speaker 1: of the black or dark stuff, you might just have
• 7:39
  Speaker 1: a universe that's full of hydrogen, looking pretty boring. I
• 7:43
  Speaker 1: suppose it might be the odd reactionary event that would
• 7:47
  Speaker 1: create something, but it wouldn't be wouldn't be much to
• 7:51
  Speaker 1: look at.
• 7:51
  Speaker 4: It to be Boarsville. Yes, well, it would be Boarsville
• 7:57
  Speaker 4: because without the formation of stars and galaxies, in particular stars.
• 8:01
  Speaker 4: Without the formation of stars, you don't get the heavy elements.
• 8:04
  Speaker 4: All you get is a universe with hydrogen, helium, a
• 8:07
  Speaker 4: little bit of lithium, and a couple of other things,
• 8:08
  Speaker 4: and that's it. So it would be a very boring place.
• 8:13
  Speaker 4: And talking of that, that is one of the main
• 8:17
  Speaker 4: targets of the square kilometer array, because cold hydrogen actually
• 8:21
  Speaker 4: radiates in relatively low frequency radio waves, and the square
• 8:28
  Speaker 4: kilometer array is going to be able to look so
• 8:31
  Speaker 4: far into space in other words, so far back in
• 8:33
  Speaker 4: time that it can see the dark ages when the
• 8:36
  Speaker 4: first stars have not yet come into being, and all
• 8:39
  Speaker 4: there was was cold hydrogen. So the built and map
• 8:41
  Speaker 4: that cold hydrogen and see whether it does actually fall
• 8:45
  Speaker 4: on the cosmic web as we believe it did.
• 8:48
  Speaker 1: Fascinating, fascinating. Reynald the Answery A question was it'd be
• 8:54
  Speaker 1: a very different universe without any of that stuff. Probably
• 8:57
  Speaker 1: pretty boring, and it was probably always there at the
• 9:02
  Speaker 1: beginning dark matter and dark energy perhaps as well. So yeah,
• 9:07
  Speaker 1: it's a great question, Thanks for sending it in. Our
• 9:10
  Speaker 1: next question, Fred comes from one of our regular although
• 9:15
  Speaker 1: we haven't heard from him in a while, Sendor Interes buddy.
• 9:20
  Speaker 2: Most case, that's his buddy from order again. How much
• 9:23
  Speaker 2: is they energy of the universe is kind of like
• 9:31
  Speaker 2: gone Basically.
• 9:34
  Speaker 5: He's never going to touch anything or is going to
• 9:37
  Speaker 5: just continue forever like light or gravitational waves, plus maybe
• 9:43
  Speaker 5: the potential of the energy.
• 9:44
  Speaker 2: Of moving object. How much of the viewers's energy is
• 9:47
  Speaker 2: tied up that way? Gay, I got one? Not one
• 9:49
  Speaker 2: more question?
• 9:52
  Speaker 5: Is it possible to calculate the age of the universe
• 9:54
  Speaker 5: from the half life of uranium or liquum. All right, guys,
• 9:58
  Speaker 5: keep up the good work, love the vodcas.
• 10:01
  Speaker 3: Thank you, buddy.
• 10:02
  Speaker 1: That's two very very good questions, so we'll tackle them
• 10:08
  Speaker 1: one at a time. He was asking about energy that's
• 10:11
  Speaker 1: been lost.
• 10:12
  Speaker 3: In the universe.
• 10:13
  Speaker 1: I assume he means over the time the universe has existed,
• 10:19
  Speaker 1: there was a big bang, everything expanded very quickly, and
• 10:23
  Speaker 1: then it slowed down out speeding up. There's a lot
• 10:27
  Speaker 1: been happening over billions and billions of years. But is
• 10:31
  Speaker 1: there energy loss in that process?
• 10:37
  Speaker 4: A great question that I'm thinking aloud here, Andrew, So, so, yeah,
• 10:47
  Speaker 4: the energy budget of the universe is really interesting because
• 10:52
  Speaker 4: it sort of ties in with the mass of the
• 10:54
  Speaker 4: universe as well. You know, mass, as we know, has
• 10:57
  Speaker 4: an intrinsic energy. Buddy is talking about the kinetic energy
• 11:06
  Speaker 4: of moving objects, and that's certainly an energy component, but
• 11:13
  Speaker 4: I think it is vanishingly small compared with the equivalent
• 11:18
  Speaker 4: of the mass of the universe when you convert it
• 11:21
  Speaker 4: to energy with the equals mc squared. So most of
• 11:24
  Speaker 4: the energy of the universe is tied up, sorry, most
• 11:28
  Speaker 4: of the Yeah, so most of the energy of the universe.
• 11:34
  Speaker 4: Getting myself into knot here. If you regard mass as
• 11:38
  Speaker 4: part of the mass energy budget of the universe, and
• 11:41
  Speaker 4: you can draw a pie chart, the stuff we can
• 11:44
  Speaker 4: see is about five percent of that energy budget. So
• 11:48
  Speaker 4: that's all the mass equivalent the energy equivalent of all
• 11:51
  Speaker 4: the mass in the universe, and it's very very small
• 11:56
  Speaker 4: compared with dark matter, which is about five times bigger.
• 12:00
  Speaker 4: And then the rest, which is seventy five or eighty
• 12:04
  Speaker 4: about seventy five percent is dark energy. So dark energy
• 12:08
  Speaker 4: is by far the biggest energy content of the universe,
• 12:11
  Speaker 4: and the rest almost doesn't matter.
• 12:14
  Speaker 3: You know.
• 12:14
  Speaker 4: It is an incredible situation that we have that the
• 12:19
  Speaker 4: biggest energy component of the universe is something we actually
• 12:22
  Speaker 4: don't understand, making the universe expand ever more rapidly. So yeah,
• 12:28
  Speaker 4: really very very interesting. Just moving on to uranium. Uraniums
• 12:35
  Speaker 4: are not something that you can use to determine the
• 12:39
  Speaker 4: age of the universe because it was created in super
• 12:43
  Speaker 4: and over explosions which occurred after the universe was formed.
• 12:48
  Speaker 4: With heavy elements like uranium are created within massive star
• 12:55
  Speaker 4: either collisions, neutron star collisions, or massive super and ova eruptions.
• 13:01
  Speaker 4: You can use uranium obviously, it has a half life,
• 13:05
  Speaker 4: and you can. I think that might be one of
• 13:07
  Speaker 4: the ways that you determine the age of the Earth. Actually,
• 13:10
  Speaker 4: when I think about it, four point six billion years,
• 13:14
  Speaker 4: I think the age of the Earth is partly due
• 13:20
  Speaker 4: to our understanding of the radioactive decay of isotopes like uranium.
• 13:25
  Speaker 4: So yes, it's got a place in cosmology, but not
• 13:30
  Speaker 4: in regard to the Big Bang itself.
• 13:33
  Speaker 1: Okay, you also mentioned lithium same day, did.
• 13:35
  Speaker 4: Yeah, Now, lithium is not That's what I was just
• 13:38
  Speaker 4: looking up. It's I think I'm not aware of the
• 13:44
  Speaker 4: radioactive properties of lithium. Let me put it that way.
• 13:48
  Speaker 2: Okay.
• 13:49
  Speaker 1: Yeah, Well, we know about its properties when it comes
• 13:52
  Speaker 1: to energy use on Earth, and it's a dwindling resource.
• 13:58
  Speaker 1: So they've got to find something else eventually. And I
• 14:01
  Speaker 1: think they're are working on sodium batteries and there's plenty
• 14:05
  Speaker 1: of that stuff around. But yeah, So if you can't
• 14:09
  Speaker 1: use the half life of uranium olthium to calculate the
• 14:12
  Speaker 1: age of the universe, what do you use.
• 14:18
  Speaker 4: The first way it was worked out was simply by
• 14:21
  Speaker 4: the measure measuring the Hubble constant, which is the rate
• 14:24
  Speaker 4: at which the universe is expanding. If you invert the
• 14:27
  Speaker 4: Hubble constant, you get the time how long it's been
• 14:30
  Speaker 4: expanding for You can basically use that simple number to
• 14:35
  Speaker 4: work out when everything was altogether in one place. But
• 14:38
  Speaker 4: that assumes that the expansion has been uniform throughout, and
• 14:42
  Speaker 4: we don't believe that's the case now, so you've got
• 14:44
  Speaker 4: to modify it. So these days it's a combination of
• 14:47
  Speaker 4: looking at the distribution of galaxies in the universe, plus
• 14:51
  Speaker 4: are observations of the flash of the Big Bang, which
• 14:55
  Speaker 4: we could still see, of course, is a cosmic microwave
• 14:57
  Speaker 4: background radiation, and you can deduce from that how the universes,
• 15:02
  Speaker 4: because you know, it was visible light when it left
• 15:04
  Speaker 4: and it's now microwaves, and that's the central calculation as well.
• 15:08
  Speaker 1: Yeah, I suppose in terms of dwindling energy or lost
• 15:12
  Speaker 1: energy in the universe, you can you can look at
• 15:14
  Speaker 1: I think we've spoken about it before. You can look
• 15:15
  Speaker 1: at photons, which do die, especially if they hit something,
• 15:22
  Speaker 1: but that energy transfers into something else, does it.
• 15:25
  Speaker 4: That's correct, Yeah, so it's conserved. That's right there. You go.
• 15:29
  Speaker 1: Okay, thank you buddy. Great to hear from you. It's
• 15:32
  Speaker 1: been a while. I hope you're well, our next question
• 15:35
  Speaker 1: comes from Oh, hang on a second, we've got to
• 15:38
  Speaker 1: do this first broad piece MUDs there we go, always
• 15:45
  Speaker 1: got to check one of those in. Ben has sent
• 15:48
  Speaker 1: us a question, and Ben asks, in the early universe
• 15:54
  Speaker 1: it was physically much smaller, but the total amount of
• 15:57
  Speaker 1: matter slash energy was the same, so everything was much
• 16:01
  Speaker 1: closer together than now. So wouldn't that make it much
• 16:03
  Speaker 1: easier to build stars, galaxies and stuff, even super massive
• 16:07
  Speaker 1: black holes? Yet we are supposed to be surprised that
• 16:10
  Speaker 1: these structures existed in the very early days. Why so
• 16:14
  Speaker 1: I would be surprised if huge compact structures didn't form
• 16:18
  Speaker 1: quickly as the ingredients were so readily available, Ben Hardy,
• 16:24
  Speaker 1: Thank you, Ben. We've kind of been talking about that
• 16:26
  Speaker 1: stuff as a part of today's program. And yes, you
• 16:31
  Speaker 1: bring up an interesting point. We get excited when we
• 16:35
  Speaker 1: find a primordial black hole or an ancient galaxy that
• 16:40
  Speaker 1: seems to almost be as old as the universe itself,
• 16:44
  Speaker 1: which has happened in recent times. Should we be surprised,
• 16:48
  Speaker 1: Fred or is been onto something? Look, it was all
• 16:52
  Speaker 1: there in the first place. Why are we getting super
• 16:55
  Speaker 1: super excited about it?
• 16:58
  Speaker 3: So?
• 16:58
  Speaker 4: Yeah, so if our models galaxy formation were perfect and
• 17:03
  Speaker 4: the perfect representation of reality, then we wouldn't be surprised
• 17:08
  Speaker 4: because the models will predict that. But the models need
• 17:12
  Speaker 4: fine tuning, so those surprises are I think. To be honest,
• 17:18
  Speaker 4: they're often beat up by the media, including its base notes.
• 17:24
  Speaker 4: So there is an element of you know, researchers who
• 17:32
  Speaker 4: are the ones who put together models of the way
• 17:35
  Speaker 4: galaxies form and evolve. They're the ones who've in some
• 17:40
  Speaker 4: ways had to rewrite their models. They've had to tune
• 17:42
  Speaker 4: the parameters. We had a talk at the fiftieth anniversary
• 17:48
  Speaker 4: of the End of Australian Telescope, that symposium that I
• 17:50
  Speaker 4: was chairing as the local Organizing Committee chair sorry Science
• 17:56
  Speaker 4: Organizing Committee chair not very long ago. One of the
• 17:59
  Speaker 4: talks was about exactly this, and that particular speaker said
• 18:04
  Speaker 4: we shouldn't be surprised that these structures formed so early
• 18:08
  Speaker 4: in the universe because the ingredients were there exactly as
• 18:12
  Speaker 4: Ben says, But you know, there's a bit more to
• 18:16
  Speaker 4: it than that. You've got to have the gravitational pull
• 18:20
  Speaker 4: that's provided by that cosmic web structure that we were
• 18:22
  Speaker 4: talking about a few minutes ago, that needs to be
• 18:24
  Speaker 4: in place as well, and that must have formed very
• 18:27
  Speaker 4: very early on in the history of the universe. That's
• 18:30
  Speaker 4: what we learn from the square kilometer array. We might
• 18:34
  Speaker 4: get surprises from the square kilometer array as well, because
• 18:37
  Speaker 4: we think there is at least, you know, at least
• 18:40
  Speaker 4: a time of more than one hundred million years when
• 18:44
  Speaker 4: the universe went through the dark ages there were no
• 18:46
  Speaker 4: stars shining. Now, that might turn out to be an
• 18:49
  Speaker 4: underestimate or an overestimate, and it might surprise the theorists
• 18:53
  Speaker 4: when we start to get the results from the square
• 18:55
  Speaker 4: kilometer array, which won't be too far down the track.
• 18:57
  Speaker 4: I don't think maybe two thousand to ask you.
• 19:00
  Speaker 1: That it can't be too long before they switch that on,
• 19:04
  Speaker 1: but it is still a while.
• 19:07
  Speaker 4: Yeah, it's twenty twenty eight or thereabouts. Yeah, right, but
• 19:12
  Speaker 4: there will switch on bits of it beforehand, so we
• 19:15
  Speaker 4: might glean stuff. It is an array, so you know,
• 19:18
  Speaker 4: it's not just a single telescope. Yes, tell us, Yeah, it.
• 19:23
  Speaker 1: Was very good, Thank you, Ben. I think we basically
• 19:27
  Speaker 1: answered it that yes, because of modeling and it's not
• 19:31
  Speaker 1: an exact science. These discoveries are quite surprising from time
• 19:35
  Speaker 1: to time, and not all us stuff was there in
• 19:39
  Speaker 1: the first place, I suppose fred because the consequence of
• 19:43
  Speaker 1: the Big Bang and that mix of materials that created
• 19:47
  Speaker 1: more materials and new materials and new discoveries being made
• 19:51
  Speaker 1: as a consequence of that, I suppose.
• 19:54
  Speaker 2: Yeah.
• 19:54
  Speaker 4: So, I mean the modeling of the Big bangs fairly
• 19:58
  Speaker 4: pretty well.
• 19:59
  Speaker 3: So up.
• 20:02
  Speaker 4: And then it's within the first few minutes that you
• 20:05
  Speaker 4: actually get atoms forming, but they are hydrogen and helium.
• 20:09
  Speaker 1: Uh.
• 20:09
  Speaker 4: And then you've got to wait a long time, probably
• 20:14
  Speaker 4: one hundred million years before you started getting carbon and
• 20:18
  Speaker 4: oxygen and the other things that are formed by the
• 20:20
  Speaker 4: interior of stars. And that you know, that's a fairly
• 20:24
  Speaker 4: coherent picture, which, as I said, will be demonstrated, we
• 20:29
  Speaker 4: hope by the square kilometer ray. What will be a
• 20:32
  Speaker 4: surprise there is if they when they analyze the signal
• 20:37
  Speaker 4: coming from that early gas, if heavy elements were present
• 20:41
  Speaker 4: in that early prime audio gas, then we really have
• 20:44
  Speaker 4: to start rewriting the textbooks because at the moment we
• 20:48
  Speaker 4: don't think there were any. So there's a there's a
• 20:50
  Speaker 4: challenge for the square kilometerra and that would probably win
• 20:53
  Speaker 4: a Nobel Prize a discovery like that.
• 20:55
  Speaker 1: Yeah, I imagine. So, so Ben's basically asked his question,
• 20:59
  Speaker 1: A few is too early.
• 21:01
  Speaker 4: Yes, that's right. So if a Nobel price came from that,
• 21:05
  Speaker 4: it will please me enormously, because I'm on record in
• 21:08
  Speaker 4: Hansard as having promised the government that the square kilometer
• 21:12
  Speaker 4: array would win a Nobel prize.
• 21:16
  Speaker 3: Oh day, Yeah that was a few years.
• 21:22
  Speaker 1: I'm just going to write a note because we're going
• 21:23
  Speaker 1: to follow that up. Okay, thanks Ben, Okay, we take
• 21:32
  Speaker 1: space nuts and our final question today comes from youngst.
• 21:39
  Speaker 3: Hello, space Nuts. This is the young from the Forest
• 21:42
  Speaker 3: of Dalston and Sweden. As we all know, Saturn's moon,
• 21:46
  Speaker 3: Titan is a very special place. So here's my question.
• 21:51
  Speaker 3: How did Titan become so special? How did it accumulate
• 21:55
  Speaker 3: stick nitrogen atmosphere and know it's meeting and eating so
• 21:59
  Speaker 3: does some months of out planets. Only Titan has an atmosphere.
• 22:04
  Speaker 3: What is it about Titan that made it become different
• 22:07
  Speaker 3: from all the other moons? And another related question. This
• 22:13
  Speaker 3: often said that Mars is too small to retain an
• 22:16
  Speaker 3: atmosphere in the long term, the Titan is even smaller.
• 22:20
  Speaker 3: How came Titan carry in an atmosphere when Mars cannot? Thanks?
• 22:25
  Speaker 1: Very great show, Thank you, Yes, great to hear from
• 22:30
  Speaker 1: somebody in Sweden and gee, that were great questions, especially
• 22:36
  Speaker 1: that last part comparing Mars that couldn't hold an atmosphere
• 22:40
  Speaker 1: to Tighten that's smaller, that can hold an atmosphere, and
• 22:44
  Speaker 1: had it Titan get its atmosphere in the first place
• 22:46
  Speaker 1: because it's unique. I think that was a reasonably good
• 22:51
  Speaker 1: paraphrasing it.
• 22:52
  Speaker 4: Solo phrases it very well. Yeah, and I can paraphrase
• 22:55
  Speaker 4: the answer, which is basically, I don't know.
• 22:59
  Speaker 2: I'm home. Yeah.
• 23:01
  Speaker 4: I think we will do some of homework on this,
• 23:02
  Speaker 4: but it's a great question, yes, and I just thinking
• 23:08
  Speaker 4: about it. You know, with Mars, the obvious difference between
• 23:13
  Speaker 4: Mars and Titan is that Mars, well, Mars is bigger
• 23:19
  Speaker 4: than Titan, but Mars is much closer to the Sun
• 23:23
  Speaker 4: and so well, it's not in the Goldilock zone, it's
• 23:26
  Speaker 4: it's near enough to the Sun that we think the
• 23:29
  Speaker 4: Sun's radiation. By that, I mean the sub atomic particles
• 23:33
  Speaker 4: has helped us strip off the atmosphere from Mars, which
• 23:40
  Speaker 4: is you know, some of it, some of it is water,
• 23:42
  Speaker 4: baker that's frozen frozen out, a lot of that, but
• 23:45
  Speaker 4: a lot of it was dissociated into well, the water
• 23:50
  Speaker 4: was certainly dissociated into hydrogen and oxygen, and the hydrogen
• 23:53
  Speaker 4: has just gone into space. Yeah, likewise, probably some of
• 23:57
  Speaker 4: the carbon dioxide. It's so I think it's there's a
• 24:01
  Speaker 4: temperature difference there. But once you get to Jupiter, now
• 24:05
  Speaker 4: Ganymede is bigger than Titan, Ganymede doesn't have a sceric
• 24:09
  Speaker 4: of an atmosphere. There's nothing there at all. So it's
• 24:12
  Speaker 4: a really interesting question why Titan should have that thick atmosphere.
• 24:18
  Speaker 4: And I am not an expert on planetary signs, but
• 24:22
  Speaker 4: I will take that one un notice because I think
• 24:24
  Speaker 4: that's worth following up just to find out. It's such
• 24:26
  Speaker 4: a great question, and it's a you know, it's glaringly obvious.
• 24:29
  Speaker 4: Why is this body in the outer Solar System? Why
• 24:33
  Speaker 4: is it clung onto an atmosphere that is thick and
• 24:37
  Speaker 4: murky when we've got a similar sized object, Ganymede, not
• 24:45
  Speaker 4: that far nearer to the inner Solar System in orbit
• 24:49
  Speaker 4: around Jupiter, that doesn't have any side of an atmosphere
• 24:53
  Speaker 4: like that. So that is one I'll come back to
• 24:56
  Speaker 4: and thank you for the question.
• 24:59
  Speaker 1: Just throw it. There could be something to do with
• 25:02
  Speaker 1: the volatility of Titan. It's it's it's volcanic, is it not?
• 25:07
  Speaker 1: And it's throwing up a lot of these nasty, smelly guesses.
• 25:11
  Speaker 1: And could it constantly be renewing its atmosphere, which anyway
• 25:15
  Speaker 1: it cannot.
• 25:16
  Speaker 4: Perhaps these are the cry of cry of volcanoes. We
• 25:20
  Speaker 4: think it's a mixture of water and pneumonia that comes
• 25:23
  Speaker 4: up from them and not, you know, not what the
• 25:27
  Speaker 4: kind of thing that we imagine when we think of
• 25:29
  Speaker 4: a terrestrial volcano. So the volcanoes are coming up from
• 25:32
  Speaker 4: the ocean layer beneath the ice of Titan, because titan
• 25:35
  Speaker 4: surface is solid ice, as we believe it is Ganymedes.
• 25:39
  Speaker 4: So it's a it's such a contrast, I mean, in
• 25:42
  Speaker 4: a sense. My first thought about this was, well, gas
• 25:47
  Speaker 4: giants are you know, they grow their gasiness because they've
• 25:52
  Speaker 4: got a massive core that's been built up by the
• 25:59
  Speaker 4: fact that that the beyond the ice line so is
• 26:02
  Speaker 4: has formed and they've got probably got an icy core.
• 26:07
  Speaker 4: Whether you can apply the same argument to Titan, I'm
• 26:11
  Speaker 4: not sure. I need to check on that. So, yeah,
• 26:15
  Speaker 4: thanks for the question, and we'll we'll have a look
• 26:17
  Speaker 4: at it.
• 26:18
  Speaker 3: I'm going to put.
• 26:21
  Speaker 1: We'll put a pin in that one and try and
• 26:24
  Speaker 1: come back to it in a later episode. But great question.
• 26:27
  Speaker 3: It's very very good.
• 26:28
  Speaker 1: And hope all as well in Sweden. Are you're heading
• 26:31
  Speaker 1: into the colder month so I won't be visiting for
• 26:34
  Speaker 1: a while, Well we will.
• 26:36
  Speaker 4: We'll be there next not next month, but the month after.
• 26:39
  Speaker 1: We've been so wonderful.
• 26:42
  Speaker 4: Ye, excellent.
• 26:45
  Speaker 1: Okay, that's it for today. Thanks to everyone who's sending questions.
• 26:49
  Speaker 1: Don't forget you can send us questions as well via
• 26:52
  Speaker 1: our website space nuts dot Io. Just click on the
• 26:56
  Speaker 1: A M A link up the top and send us
• 26:59
  Speaker 1: your questions through that and have a look around while
• 27:02
  Speaker 1: you're there, particularly the space nuts shop or the space
• 27:05
  Speaker 1: Nuts support a button if you want to push that.
• 27:08
  Speaker 1: What it does is as soon as you push that button,
• 27:10
  Speaker 1: it sends out a trojan and and your bank bank account.
• 27:15
  Speaker 1: No it doesn't, No, no it doesn't.
• 27:17
  Speaker 4: Don't even joke about that.
• 27:19
  Speaker 3: No it shouldn't.
• 27:20
  Speaker 1: Really good grief, No it doesn't. It's purely voluntary. Thanks.
• 27:27
  Speaker 1: Fred is always great to chat and great questions again
• 27:31
  Speaker 1: this week.
• 27:32
  Speaker 4: Well they're just they're terrific questions. Yeah, thank you very
• 27:35
  Speaker 4: much everybody, and Thanks Andrew.
• 27:37
  Speaker 1: No worries, catch you soon, Professor Fred Wat's an astronomer
• 27:40
  Speaker 1: at large. And thanks to Hu in the studio for
• 27:43
  Speaker 1: telling me about the trojan horse problem we've been having
• 27:45
  Speaker 1: now and I'm kidding again No he didn't, although he's
• 27:49
  Speaker 1: working on it. And from me Andrew Dunkley, thanks for
• 27:51
  Speaker 1: your company. Will catch you on the very next episode
• 27:53
  Speaker 1: of Space Nuts. See it then, Bye bye Nuts.
• 27:57
  Speaker 3: You'll be listening to the Space Nuts podcast.
• 28:02
  Speaker 1: Available at Apple Podcasts, Spotify, iHeartRadio, or your favorite podcast player.
• 28:08
  Speaker 3: You can also stream on demand at bites dot com.
• 28:11
  Speaker 4: This has been another quality podcast production from nights dot com.