Latest / Space Nuts: Astronomy Insights & Cosmic Discoveries / Oceans, Space-Time Stiffness & Ganymede's Hidden Crater: A Cosmic Q&A

Transcript

Oceans, Space-Time Stiffness & Ganymede's Hidden Crater: A Cosmic Q&A · Space Nuts: Astronomy Insights & Cosmic Discoveries

• 0:00
  Speaker 1: Hi there, thanks for joining us again. This is Space Nuts,
• 0:03
  Speaker 1: a Q and A edition. My name is Andrew Dunkley,
• 0:06
  Speaker 1: your host. It's good to have your company. Questions today
• 0:09
  Speaker 1: coming from Matt, who wants to talk about the oceans
• 0:12
  Speaker 1: on Earth. Doug is asking about the stiffness of space time.
• 0:16
  Speaker 1: We have talked about that before, but he's got a
• 0:18
  Speaker 1: different idea. John is asking questions about a new antenna array,
• 0:23
  Speaker 1: and Rusty is honing in on something we talked about
• 0:27
  Speaker 1: late last year, the largest impact crater.
• 0:31
  Speaker 2: He wants to go further than the surface of the Earth.
• 0:33
  Speaker 2: So we'll talk about all of that on this episode of.
• 0:37
  Speaker 1: Space Nuts fifteen second Channel ten nine ignition sig on
• 0:45
  Speaker 1: Space Nuts NI or three two Space Nuts as when
• 0:52
  Speaker 1: I report it, Neil's good and he's done all his homework.
• 0:56
  Speaker 2: He's ready to go.
• 0:57
  Speaker 1: It's Professor Fred Watson, astronomer at LA TE Right.
• 1:00
  Speaker 3: I've just realized there was one bit of homework that
• 1:03
  Speaker 3: I didn't do, which mind it will be all right.
• 1:08
  Speaker 2: Well, it's a thing called guessing. We can do that.
• 1:11
  Speaker 2: We can do that. That'll solve it. Shall we just
• 1:15
  Speaker 2: get straight into it?
• 1:17
  Speaker 3: I think we all too, Yes, I think that would
• 1:18
  Speaker 3: be a very good thing to do.
• 1:20
  Speaker 2: All right.
• 1:21
  Speaker 1: Our first question is a text question from Matt High,
• 1:24
  Speaker 1: Andrew and Fred.
• 1:25
  Speaker 2: I have a question for you.
• 1:26
  Speaker 1: That's good because this is the Q and A segment,
• 1:28
  Speaker 1: so it's good that you've got a question. I was
• 1:30
  Speaker 1: thinking about what the Earth's surface would look like as
• 1:34
  Speaker 1: a rocky planet without any water. Imagine if you happen
• 1:38
  Speaker 1: to live by the sea and could stand on the surface,
• 1:41
  Speaker 1: how different you're part of the world would suddenly look.
• 1:45
  Speaker 1: You'd probably fall a long way too in some parts
• 1:49
  Speaker 1: of the world. That started me thinking, what is it
• 1:53
  Speaker 1: that determines how far our oceans got filled up? Why,
• 1:58
  Speaker 1: for instance, aren't there smaller and why aren't they much
• 2:03
  Speaker 1: smaller and only a max of say a few hundred
• 2:06
  Speaker 1: meters deep. What's the physics that governs how much total
• 2:09
  Speaker 1: water we ended up having on Earth? And if you
• 2:14
  Speaker 1: can share some wisdom on that, it would be grand.
• 2:16
  Speaker 2: Thank you.
• 2:16
  Speaker 1: I love the podcast, been listening for a few years.
• 2:20
  Speaker 2: But this is my first question. Keep up the good work.
• 2:23
  Speaker 2: Thanks Matt, well thanks for sending in the question. We've
• 2:27
  Speaker 2: talked about how.
• 2:28
  Speaker 1: Water ended up on Earth, and there are all sorts
• 2:30
  Speaker 1: of Initially the thought was it's carried by asteroids, but
• 2:34
  Speaker 1: then they started thinking, know that they wouldn't carry enough.
• 2:38
  Speaker 1: And the latest theory is that when the accretion of
• 2:43
  Speaker 1: the planet happened.
• 2:44
  Speaker 2: The water was already there, which would.
• 2:47
  Speaker 1: Probably go a long way to answering Matt's question about
• 2:50
  Speaker 1: how come there's this much.
• 2:52
  Speaker 3: Yes, maybe that's right. In fact, you probably answered it
• 2:56
  Speaker 3: in that regard, although I think the astroid and comet
• 3:01
  Speaker 3: theory still carries weight and holds water. It holds waters.
• 3:07
  Speaker 3: I was avoiding that term. The thing that put doubt
• 3:12
  Speaker 3: on that was the mixture between heavy water and normal water,
• 3:18
  Speaker 3: the isotope ratio, because that mixture in the earth sotionis
• 3:23
  Speaker 3: doesn't really match what we find in comets because we
• 3:27
  Speaker 3: can analyze the vapors that they give off when when
• 3:30
  Speaker 3: they get near the sun. And I mean, in fact,
• 3:33
  Speaker 3: we brought samples back from certainly from asteroids. So but
• 3:39
  Speaker 3: you're right. I think the prevalent idea is that the
• 3:44
  Speaker 3: water was intrinsic to the Earth's formation and maybe it
• 3:48
  Speaker 3: just got topped up a bit by asteroids and comets.
• 3:52
  Speaker 2: So that does.
• 3:53
  Speaker 3: To some extent answer the question. It is to do
• 3:56
  Speaker 3: with the you know, with the inherent mix molecular mix
• 4:01
  Speaker 3: of the constituents of the cloud of gas and dust
• 4:05
  Speaker 3: from which the Earth and the Sun and the Solar
• 4:08
  Speaker 3: System were formed. I think it's not necessarily a done
• 4:20
  Speaker 3: deal though, because we think about some of the ice
• 4:25
  Speaker 3: moons of the Solar System, which are effectively covered in water.
• 4:31
  Speaker 3: They have far more water than the Earth has in
• 4:33
  Speaker 3: its oceans. And I'm talking now about places like Europa,
• 4:37
  Speaker 3: like Titan Saturn's moon, Titan juice to Moon Europa. These
• 4:41
  Speaker 3: are ice worlds, have got a liquid water ocean with
• 4:46
  Speaker 3: a covering of solid ice on top of that. So
• 4:49
  Speaker 3: they're basically global water worlds, except they're covered with ice.
• 4:55
  Speaker 3: So a bigger world of that kind would have a
• 5:00
  Speaker 3: global ocean. And we when we're talking about K two
• 5:03
  Speaker 3: eighteen B, that planet whose atmosphere has shown some possible
• 5:09
  Speaker 3: biomarker chemicals. One of the possible scenarios on K two
• 5:15
  Speaker 3: eighteen B is a world that is actually covered in water,
• 5:19
  Speaker 3: that it's a global ocean, that it's got a thick
• 5:21
  Speaker 3: enough atmosphere that the atmospheric pressure balances out the water surface.
• 5:26
  Speaker 3: So you've got the situation like we have on Earth,
• 5:28
  Speaker 3: where you've got equilibrium between the liquid and the atmosphere.
• 5:33
  Speaker 3: So it may be that, you know, our Earth could
• 5:37
  Speaker 3: have had more water. Maybe some of it's evaporated, maybe
• 5:41
  Speaker 3: some of it has dissociated into its component chemicals, component
• 5:47
  Speaker 3: elements hydrogen and oxygen, which have been lost into space,
• 5:51
  Speaker 3: as we think has happened on the planet Mars. So
• 5:54
  Speaker 3: maybe you know, there is certainly snowball. Earth is one
• 5:58
  Speaker 3: of the things that we think happened in the history
• 6:01
  Speaker 3: of our planet, that it was covered with ice, with
• 6:04
  Speaker 3: an icy surface. It's a great question that that asks, though,
• 6:11
  Speaker 3: about you know what the Earth will be like if
• 6:13
  Speaker 3: you imagined it without the ocean? Those trenches. What's the
• 6:18
  Speaker 3: deepest one eight kilometers or something like that, Yes, and Andreas,
• 6:21
  Speaker 3: I think yes, which will be pretty impressive.
• 6:25
  Speaker 1: Yeah, can you imagine the Earth without water? Yes, Andreas, No.
• 6:32
  Speaker 2: It's not. And it's the what's it called Pacific Trench?
• 6:37
  Speaker 3: Yes, it's a Pacific one. I don't remember.
• 6:40
  Speaker 1: Either, the Marinara Trench.
• 6:43
  Speaker 3: That's the one.
• 6:44
  Speaker 2: Yeah, it's.
• 6:47
  Speaker 1: It's incredibly deep.
• 6:50
  Speaker 2: It's about.
• 6:53
  Speaker 1: Yeah, I'm just trying to find it now. Yeah, if
• 6:56
  Speaker 1: you imagine Earth without water, you could do some incredible
• 7:01
  Speaker 1: sky diving there I reckon without having to catch a plane. Yeah,
• 7:07
  Speaker 1: but getting out that would be the fun part, I imagine.
• 7:10
  Speaker 1: But yeah, it's I can't find the depth of it,
• 7:13
  Speaker 1: but it is. It is something massive. But they have
• 7:16
  Speaker 1: sent submarines down deep into it.
• 7:21
  Speaker 3: Yes, with other people on board.
• 7:22
  Speaker 2: Yeah.
• 7:23
  Speaker 1: Here it is twenty six eight hundred and fifty feet
• 7:26
  Speaker 1: or eight one hundred and eighty four meters deep. What
• 7:30
  Speaker 1: I said, Yeah, you're right, you're doing very well. So, Matt,
• 7:34
  Speaker 1: if the Earth did not have oceans.
• 7:38
  Speaker 2: It would look very, very different.
• 7:40
  Speaker 1: It would be quite spectacular in places, to say the least,
• 7:45
  Speaker 1: because there are mountain ranges under there the ocean which
• 7:48
  Speaker 1: we can't see. Yeah, and even you've got you've got
• 7:51
  Speaker 1: things like Hawaii, which is a super volcano, but you
• 7:53
  Speaker 1: can only see the tip of it.
• 7:55
  Speaker 3: Yes, I do wonder though. It's so you know, there
• 8:00
  Speaker 3: are significant differences. So plate tectonics is the key thing here.
• 8:06
  Speaker 3: The ocean plates are different from the continental plates, and
• 8:10
  Speaker 3: possibly a lot of that is the fact that they're
• 8:12
  Speaker 3: being weighed down by the water, and so without the
• 8:16
  Speaker 3: water they might bounce up a bit and you might
• 8:18
  Speaker 3: get a much more level playing field compared with what
• 8:22
  Speaker 3: it's like now.
• 8:23
  Speaker 1: Well you see evidence of that around New Zealand where
• 8:27
  Speaker 1: the Milford Sound and all the other and Dusty Sound
• 8:30
  Speaker 1: and all those beautiful areas are they're still lifting after
• 8:33
  Speaker 1: the ice Age where the glaciers compressed the ground, and
• 8:37
  Speaker 1: you can see evidence of the rebound effects. So, yeah,
• 8:41
  Speaker 1: you're right because the water ways, I don't know how
• 8:46
  Speaker 1: you'd measure it, but it's incredibly heavy, it's and putting
• 8:49
  Speaker 1: a lot of pressure on those areas. Yeah, the Earth
• 8:52
  Speaker 1: could look very different if all the water disappeared, and
• 8:56
  Speaker 1: it probably bounced back pretty quickly. Yes, in this in
• 9:00
  Speaker 1: geological time, that's right, Yes, yes, absolutely, Thanks for the question, Matt,
• 9:05
  Speaker 1: Howpe we adequately answered that for you. Our next question
• 9:09
  Speaker 1: is an audio a question from Doug Hi.
• 9:12
  Speaker 4: This is Doug and Hazel the Wonder Doodle calling from Whitby, Ontario, Canada.
• 9:19
  Speaker 4: Second time caller. Thanks very much for the show. The
• 9:23
  Speaker 4: question today from Hazel is we've heard people talk about
• 9:28
  Speaker 4: the stiffness of space time being something like one hundred
• 9:33
  Speaker 4: billion billion times stiffer than steal and we're wondering how
• 9:39
  Speaker 4: that can be when space time doesn't matter, so to speak,
• 9:44
  Speaker 4: How can you measure the stiffness of space time, and
• 9:49
  Speaker 4: what exactly are you measuring? Thank you?
• 9:53
  Speaker 2: How long is a piece of string?
• 9:57
  Speaker 3: It's a great question, and I appreciate that one because
• 10:00
  Speaker 3: this is one that has always fascinated me. So what
• 10:03
  Speaker 3: you do is you look at the way matter distort space.
• 10:13
  Speaker 3: And we know that very very well from Einstein's general
• 10:19
  Speaker 3: theory of relativity. We know what the distortion is for
• 10:22
  Speaker 3: a given amount of mass and a given size. That's
• 10:25
  Speaker 3: why we understand black holes because of the fact that
• 10:28
  Speaker 3: the space is so highly distorted. So what you do
• 10:32
  Speaker 3: you look at the way matter distort space, and from
• 10:36
  Speaker 3: that you can determine a property called the Young's modulus
• 10:40
  Speaker 3: of space, which is a kind of geometrical property. It's
• 10:45
  Speaker 3: usually applied to solids as exactly as Doug has said,
• 10:49
  Speaker 3: you know, how can you measure its stiffness when it's.
• 10:52
  Speaker 2: Not a solid.
• 10:54
  Speaker 3: So what you do is you know that it's flexible.
• 10:56
  Speaker 3: You can see the way matter flexes it, and you
• 11:00
  Speaker 3: go from there to saying if it was a solid,
• 11:04
  Speaker 3: it would have this property. And the property we measure
• 11:06
  Speaker 3: is something called Young's modulus. I remember doing Young's modulus
• 11:11
  Speaker 3: as a physics experiment at school. You hang weights on
• 11:13
  Speaker 3: a bit of wire and that gives you the amount
• 11:17
  Speaker 3: of stretch, the stiffness of the wire with the weights
• 11:21
  Speaker 3: hanging on it, and so you can do an equivalent thing.
• 11:24
  Speaker 3: And it's exactly the number actually that that dog has said.
• 11:27
  Speaker 3: It's one hundred billion billion times stiffer than steel ten
• 11:33
  Speaker 3: to the power twenty.
• 11:35
  Speaker 2: There is a there's a paper.
• 11:36
  Speaker 3: It's pretty easy to find it on the web. It
• 11:39
  Speaker 3: was written by let me see if I can bring
• 11:43
  Speaker 3: it up. It is by Kirk T. MacDonald who's at
• 11:48
  Speaker 3: Princeton University. So this is probably the you know, the
• 11:52
  Speaker 3: almost the headquarters of gravity, because that's where where Einstein
• 11:56
  Speaker 3: did a lot of his work. He's he's got a
• 12:00
  Speaker 3: little paper that you can find online what is the
• 12:02
  Speaker 3: stiffness of space time? And the answer I've given is
• 12:05
  Speaker 3: the classical answer, the tenth to power twenty. He's got
• 12:09
  Speaker 3: a quantum answer as well, and you can throw in
• 12:14
  Speaker 3: something about cosmological sound waves and electromagnetic waves and enjoy
• 12:19
  Speaker 3: yourself with some of the equations there. But that's basically
• 12:22
  Speaker 3: where that number comes from. It comes from that paper.
• 12:24
  Speaker 1: Yeah, And it's not so much about the physical attributes
• 12:28
  Speaker 1: of the universe. It's about the fabric of space time
• 12:31
  Speaker 1: itself and.
• 12:33
  Speaker 3: The way it behaves.
• 12:35
  Speaker 1: Yeah, yeah, because we have talked about it before, and
• 12:39
  Speaker 1: I think when we first talked about it, I was
• 12:42
  Speaker 1: quite astonished by how stiff space is. Yes, in the
• 12:49
  Speaker 1: scheme of things, but when you compare it to steel,
• 12:53
  Speaker 1: I guess it puts you in a mindset of a
• 12:55
  Speaker 1: physical thing. Yeah, that's right, like an object, But that's
• 12:59
  Speaker 1: not really what it's about, all right, short answer, but
• 13:06
  Speaker 1: there's yeah, that's pretty well documented. And yeah, you can
• 13:11
  Speaker 1: even certainly look that article up, Doug and learn more
• 13:15
  Speaker 1: about it. And thanks for the question, and thanks for
• 13:18
  Speaker 1: introducing us to your puppy dog. This is Space Nuts
• 13:22
  Speaker 1: Andrew Dunkley with Professor Fred Watson, a Q and A edition.
• 13:27
  Speaker 1: If you're heading overseas soon and you want to be
• 13:30
  Speaker 1: able to get data on your mobile service or your
• 13:33
  Speaker 1: cell phone while you're in another country, you're probably thinking, well,
• 13:38
  Speaker 1: you know, how can I do it? How can I
• 13:40
  Speaker 1: get reliability? How can I get something that's not going
• 13:43
  Speaker 1: to break the bank. The answer is sale s Ai
• 13:46
  Speaker 1: l Y Saley And of course they're offering a special
• 13:51
  Speaker 1: deal for Space Nuts listeners, so don't forget the coupon
• 13:53
  Speaker 1: code space nuts when you go to the checkout sale
• 13:57
  Speaker 1: dot com slash space nuts. What they're offering is an
• 14:01
  Speaker 1: exclusive discount on e SIMS so you can save big
• 14:05
  Speaker 1: on travel data plans. You can surf the web abroad
• 14:08
  Speaker 1: without having to worry about a thing and without roaming fees. Now,
• 14:13
  Speaker 1: I did use Saley on a recent trip, so I
• 14:16
  Speaker 1: can tell you without a shadow of a doubt it works.
• 14:20
  Speaker 1: I did not have a problem with it anywhere we went,
• 14:25
  Speaker 1: and it was high quality data capture. I didn't have
• 14:29
  Speaker 1: any lag, I didn't have any problem loading pages and maps,
• 14:33
  Speaker 1: I didn't have any dropouts. It just worked, and that's
• 14:37
  Speaker 1: what you want when you're overseas, and I would have
• 14:42
  Speaker 1: no hesitation in recommending it.
• 14:44
  Speaker 2: So how do you get the deal?
• 14:45
  Speaker 1: Well, you go to sale dot com slash space nuts
• 14:49
  Speaker 1: and you click get the deal, which I'll do right now,
• 14:53
  Speaker 1: and it will take you through all the options. You
• 14:55
  Speaker 1: can pick a country that you're going to from Afghanistan
• 15:02
  Speaker 1: right through to Zimbabwe and everything in between, or you
• 15:06
  Speaker 1: can get a region. Now, getting a package for a
• 15:10
  Speaker 1: region is a really great idea because you can go
• 15:12
  Speaker 1: to several countries within that area and you're covered. And
• 15:16
  Speaker 1: the prices that are very according to which package you
• 15:20
  Speaker 1: get and where you're going. But you know it is
• 15:23
  Speaker 1: very very inexpensive. Prices very of course, but there's an exclusive.
• 15:29
  Speaker 2: Deal right now.
• 15:30
  Speaker 1: You can get this at salee dot com slash space
• 15:34
  Speaker 1: Nuts and don't forget the code space Nuts at the
• 15:39
  Speaker 1: checkout for a fifteen percent discount. Grab your deal today
• 15:43
  Speaker 1: at sale dot com slash space nuts. Get an e
• 15:48
  Speaker 1: SIM at rockbottom prices. They've cut the prices for space
• 15:52
  Speaker 1: Nuts listeners and all you have to do is go
• 15:54
  Speaker 1: online to sale dot com slash space nuts and find
• 15:58
  Speaker 1: the package that works for you from our sponsor, Saley
• 16:02
  Speaker 1: Murder Spacemuts. Our next question comes from John I live
• 16:09
  Speaker 1: in Cloudcroft, New Mexico, in the United States. Today's Albuquerque
• 16:13
  Speaker 1: New Mexico newspaper reported on NGVLA it will replace an
• 16:19
  Speaker 1: existing twenty seven and TENA array with one hundred and
• 16:22
  Speaker 1: ninety two each new foundation, four hundred and thirty tons,
• 16:26
  Speaker 1: each new antenna generating one point five terror bytes per second,
• 16:31
  Speaker 1: and each eighteen meter tall structure weighing one hundred and
• 16:36
  Speaker 1: thirty tons. How will this new antenna fit into the
• 16:40
  Speaker 1: astronomy community, and he makes a reference to the square
• 16:46
  Speaker 1: kilometer Array and Meercat arrays that are being set up
• 16:49
  Speaker 1: in Australia and South Africa. Thank you, John, I didn't
• 16:52
  Speaker 1: know about this one.
• 16:54
  Speaker 3: Yeah, it's been in the pipeline quite a while. So
• 16:57
  Speaker 3: the VLA is the very large Array in New Mexico.
• 17:02
  Speaker 3: We visited it a few years ago, a very impressive
• 17:05
  Speaker 3: set of antennas, and essentially it's been a really productive
• 17:15
  Speaker 3: machine for research. The VLA back going back to the
• 17:18
  Speaker 3: nineteen seventies, and there's a note on their website that
• 17:22
  Speaker 3: says it's been used for more than eleven thousand different
• 17:25
  Speaker 3: observing projects and had an impact on nearly every branch
• 17:29
  Speaker 3: of astronomy. So what has happening, what is happening now
• 17:34
  Speaker 3: is an upgrade to make it the next generation very
• 17:38
  Speaker 3: large array, the n GVLA, and exactly as John says,
• 17:44
  Speaker 3: it's got similarities actually to the mid frequency component of
• 17:50
  Speaker 3: the square kilometer array, which is in South Africa and
• 17:53
  Speaker 3: is basically an extension of MEERCAP, which is an existing
• 17:57
  Speaker 3: array in South Africa. So that also will have antennas
• 18:03
  Speaker 3: about two hundred, much the same as the ng VLA.
• 18:07
  Speaker 3: Will have what I was looking for. This is a
• 18:10
  Speaker 3: bit of homework that I didn't actually do. It's it's
• 18:14
  Speaker 3: it's going to have a frequency range which I am
• 18:21
  Speaker 3: not sure about. It's probably quite similar.
• 18:24
  Speaker 1: One point two gigahertz or twenty months in amis to
• 18:27
  Speaker 1: one hundred and sixteen gigaherts.
• 18:29
  Speaker 3: Okay, that's rather more, I think, the than the mid
• 18:34
  Speaker 3: frequency of the of the Square Elementary Observatory. I think though,
• 18:41
  Speaker 3: the other thing is that the ng VLA will have
• 18:48
  Speaker 3: a much wider spacing of the antennas. They're talking about
• 18:55
  Speaker 3: over nearly nine thousand kilometers. So this is continent why stuff,
• 19:01
  Speaker 3: and that's certainly bigger than the array in South Africa,
• 19:06
  Speaker 3: and so it will probably be used for different signs.
• 19:09
  Speaker 3: So the answer to John's question is that, yes, these
• 19:12
  Speaker 3: things do dovetail together, maybe in frequency and in spacing,
• 19:19
  Speaker 3: in antenna spacing. It's the sort of thing that astronomers,
• 19:25
  Speaker 3: you know, they don't tend to work in isolation. They
• 19:29
  Speaker 3: have complementary things. And it's a bit like the three
• 19:32
  Speaker 3: ELTs that are currently being planned or built. Extremely large telescopes.
• 19:37
  Speaker 3: These are optical telescopes in the twenty to thirty meter class,
• 19:41
  Speaker 3: and well, there's only one of them that's anywhere near completion,
• 19:45
  Speaker 3: and that's the European extremely Large Telescope thirty nine meter instrument.
• 19:49
  Speaker 3: But there are two others that are still on the stock.
• 19:52
  Speaker 3: So I don't know how the current funding situation in
• 19:55
  Speaker 3: the US will affect them because they require a huge
• 19:59
  Speaker 3: component of u US funding even though they're international projects.
• 20:02
  Speaker 3: They're the Giant Magellant Telescope and the and the TMT
• 20:06
  Speaker 3: the thirty meter telescope in YI, so that it's a
• 20:10
  Speaker 3: similar situation. I think you've got differences. There are nuances
• 20:13
  Speaker 3: of differences between them. They will have different strengths in
• 20:18
  Speaker 3: terms of their capabilities, and the astronomical community throughout the
• 20:22
  Speaker 3: world we'll be glad to have them because the one
• 20:25
  Speaker 3: thing that we're always short of is is astronomical facilities.
• 20:30
  Speaker 3: Telescopes are rare things when it comes to this, you know,
• 20:34
  Speaker 3: things of this size, of this stature. So great to
• 20:37
  Speaker 3: welcome the n g v l A into the you know,
• 20:41
  Speaker 3: into the mix.
• 20:42
  Speaker 1: Yeah, they say the arrail achieve high surface brightness, sensitivity
• 20:46
  Speaker 1: and high fidelity imaging on angular scales down to the
• 20:50
  Speaker 1: milli arc second, and it will extend out to one
• 20:56
  Speaker 1: thousand kilometers and it'll have longer baselines or across North
• 21:00
  Speaker 1: America and Hawaii.
• 21:02
  Speaker 2: Yeah, it's just pretty amber out.
• 21:04
  Speaker 3: Longer comes from I mean that we've seen this already
• 21:08
  Speaker 3: with the you know, the Events Horizon telescope, which goes
• 21:11
  Speaker 3: over basically the diameter of the Earth is the is
• 21:15
  Speaker 3: the baseline for that, But it's only that that's on
• 21:18
  Speaker 3: the nine telescopes or something like that, or nine observatories.
• 21:21
  Speaker 1: Yeah, I mean, I think it's great that they can
• 21:24
  Speaker 1: integrate so much hardware over such vast distances to make
• 21:28
  Speaker 1: them you know, super telescopes basically, and they're so much
• 21:32
  Speaker 1: more powerful and the other data will be very interesting.
• 21:36
  Speaker 2: I'm sure we'll be talking about it at some stage.
• 21:39
  Speaker 1: John, So keep your ear to the podcast platform that
• 21:43
  Speaker 1: you use and there will be more.
• 21:45
  Speaker 2: Thanks for the question.
• 21:47
  Speaker 1: Let's take a little break from the show to tell
• 21:49
  Speaker 1: you about our sponsor, Insta three sixty. I'm going to
• 21:53
  Speaker 1: tell you about their new camera. Just keep in mind
• 21:55
  Speaker 1: as a space Nut's listener, there's a special offer for you,
• 21:59
  Speaker 1: and we'll tell.
• 22:00
  Speaker 2: You about that in a little while.
• 22:03
  Speaker 1: But Insta three sixties new camera is very exciting. It's
• 22:07
  Speaker 1: their new flagship three hundred and sixty degree camera and
• 22:10
  Speaker 1: it does exactly what it sounds like it does. It
• 22:12
  Speaker 1: can take footage in three hundred and sixty degrees. All
• 22:16
  Speaker 1: you have to do is push record and it'll do
• 22:20
  Speaker 1: the rest. And it does it in eight K eight K,
• 22:25
  Speaker 1: and they've also enhanced the low light performance so you'll
• 22:28
  Speaker 1: get outstanding images day or night. If you're a thrill
• 22:31
  Speaker 1: seeker and you love to jump off cliffs and you
• 22:34
  Speaker 1: want a good camera to do that, this will do
• 22:36
  Speaker 1: it for you. If you like to go to deep
• 22:38
  Speaker 1: sea diving, you can do that with this camera. If
• 22:41
  Speaker 1: you just want to take a great camera on holidays,
• 22:44
  Speaker 1: it'll do that brilliantly. And it's just taking a night
• 22:49
  Speaker 1: shooting to a whole new level as well. Now with
• 22:51
  Speaker 1: three hundred and sixty degree video capture, you can get
• 22:55
  Speaker 1: everything around you just by hitting record, find your focus,
• 22:59
  Speaker 1: choose the best stangles. Later with their AI technology, they've
• 23:03
  Speaker 1: got an AI powered reframing tool and you do it
• 23:06
  Speaker 1: all through the Inster three sixty app. It couldn't be
• 23:09
  Speaker 1: more simple. They have built a really tough camera and
• 23:13
  Speaker 1: it's got replaceable lenses so if you bang something up,
• 23:16
  Speaker 1: they can just get a new lens. It'll take some
• 23:20
  Speaker 1: work to break though, because it's got very, very tough
• 23:22
  Speaker 1: optical glass. They describe it as a superior drop resistance and.
• 23:29
  Speaker 2: Plenty more as well.
• 23:31
  Speaker 1: Now, if you would like to get one of those cameras,
• 23:33
  Speaker 1: they're offering a special d off of space Nuts listeners.
• 23:36
  Speaker 1: The first thirty purchases will get a free one hundred
• 23:40
  Speaker 1: and fourteen centimeter invisible selfie stick worth around twenty five
• 23:44
  Speaker 1: dollars US. That's with your Inster three sixty x five
• 23:49
  Speaker 1: standard package purchase. All you have to do is head
• 23:51
  Speaker 1: to store dot Inster three sixty dot com and use
• 23:55
  Speaker 1: the promo code space nuts. Very important store dot instat
• 24:00
  Speaker 1: three sixty dot com and use the promo code space
• 24:03
  Speaker 1: nuts and that deal with the invisible selfie stick available
• 24:07
  Speaker 1: for the first thirty standard package purchases only. And if
• 24:11
  Speaker 1: you want more information, check out our show notes. But
• 24:14
  Speaker 1: just remember the urlstore dot Insta three sixty dot com
• 24:18
  Speaker 1: and the promo code space nuts. Now back to the show. Okay,
• 24:23
  Speaker 1: we've tacked all four systems space Nuts. The one final
• 24:27
  Speaker 1: question that this one comes from You'll never guess Rusty
• 24:31
  Speaker 1: and Donnybrook Well, Fred Andrew, it's rusty and Donnybrook, Andrew,
• 24:37
  Speaker 1: it's good to have you back.
• 24:37
  Speaker 2: But didn't iidly do a great job in your absence?
• 24:40
  Speaker 1: How did you find it?
• 24:43
  Speaker 3: Questions about the largest.
• 24:48
  Speaker 1: Crater in the Solar System.
• 24:50
  Speaker 5: I presume that the one you spoke about last September
• 24:54
  Speaker 5: on Ganymede.
• 24:56
  Speaker 3: At sixteen hundred kilometers diameter, is larger.
• 24:58
  Speaker 5: Than the one on the Moon the eight conbas So
• 25:02
  Speaker 5: the title of the largest would then change to the
• 25:06
  Speaker 5: word I anime?
• 25:06
  Speaker 2: Does it have a name yet?
• 25:09
  Speaker 3: And I'm just wondering about Triton.
• 25:14
  Speaker 6: It's odd shape would have to have come from an
• 25:18
  Speaker 6: impact decision collision, and I'm wondering if that qualifies as
• 25:24
  Speaker 6: a creator.
• 25:25
  Speaker 5: It's about it took away about a third of the
• 25:27
  Speaker 5: Moon that impact, and was that impact with the planet
• 25:34
  Speaker 5: or did it acquire its odd shape by hitting something else?
• 25:40
  Speaker 2: Thanks guys, cheez, thanks for us.
• 25:43
  Speaker 1: He always good to hear from you, chucking his curveballs.
• 25:48
  Speaker 1: I answer his first question, how do we find Heidi?
• 25:50
  Speaker 1: Heidi found us. Heidi was a Space Nuts listener and
• 25:56
  Speaker 1: she came to us to say, look, I got an
• 25:59
  Speaker 1: idea and I just want to sort of go to
• 26:01
  Speaker 1: school off you guys to find out how I can
• 26:04
  Speaker 1: get my idea out there. And her idea was a
• 26:07
  Speaker 1: podcast about the relationship between real life and science fiction.
• 26:12
  Speaker 1: And I said, well, why don't I introduce you to
• 26:15
  Speaker 1: Hugh in the studio if you can find him and
• 26:19
  Speaker 1: see what happens. And while a Hide's podcast became one
• 26:24
  Speaker 1: of the bytes dot com Stable Reality Check the Science
• 26:28
  Speaker 1: of Fiction podcasts, So that's how it happened. Heidi just
• 26:32
  Speaker 1: sort of wanted to find out how she could get
• 26:34
  Speaker 1: her idea out there, and we took her on, simple
• 26:39
  Speaker 1: as that. So yeah, it turned out to be a
• 26:41
  Speaker 1: really great podcast series.
• 26:43
  Speaker 2: Too, if you want to look it up.
• 26:45
  Speaker 1: And listen to some of the great concepts that science
• 26:49
  Speaker 1: fiction can give to real life situations or vice versa.
• 26:54
  Speaker 1: Sometimes they're a little bit out there and it would
• 26:56
  Speaker 1: never be real. But and she speaks to experts in
• 26:59
  Speaker 1: the field about the ideas of science fiction and whether
• 27:03
  Speaker 1: or not they're feasible in real life.
• 27:05
  Speaker 3: Brilliant, brilliant.
• 27:06
  Speaker 2: Yes, she did fabulous job.
• 27:07
  Speaker 1: While I was always so very pleased to be able
• 27:10
  Speaker 1: to take a break and not have to have any
• 27:13
  Speaker 1: worries at all about friend's behavior.
• 27:16
  Speaker 2: Now now the largest impact crater.
• 27:21
  Speaker 1: We did talk about that recently, and I've forgotten the
• 27:26
  Speaker 1: nuts and bolts of Rusty's question now, but I'm sure
• 27:29
  Speaker 1: you've done your homework for it.
• 27:30
  Speaker 3: It. I have two parts to us this question. One
• 27:33
  Speaker 3: is he talks about and to go back to our
• 27:40
  Speaker 3: podcast of the fourth of September last year to find
• 27:43
  Speaker 3: out what we actually said. But yes, it was a
• 27:47
  Speaker 3: story that there is evidence on Jupiter's moon Gunnymy, the
• 27:52
  Speaker 3: biggest moon in the Solar System, that sometime in the
• 27:56
  Speaker 3: past it was hit by an asteroid, probably a big
• 27:59
  Speaker 3: one hundred kilometers in diameter, which would have created a
• 28:04
  Speaker 3: creator about somewhere between fourteen hundred and sixteen hundred kilometers
• 28:09
  Speaker 3: wide on Ganymede. That's a very very big chunk of Ganymede.
• 28:13
  Speaker 3: Now that crator doesn't no longer exist, it's long gone.
• 28:18
  Speaker 3: Ganymede has a surface that's probably icy and is being
• 28:21
  Speaker 3: renewed all the time by probably you know, the activity
• 28:29
  Speaker 3: maybe even guys as of ice as we see on
• 28:32
  Speaker 3: Europa and then cellared Us, so that crater isn't there anymore.
• 28:37
  Speaker 3: And the reason why we did that story and what
• 28:41
  Speaker 3: has led to the idea that there was this cloud
• 28:44
  Speaker 3: of Ganymede back in the distant past, about four billion
• 28:48
  Speaker 3: years ago. Was what they were saying was concentric circles
• 28:54
  Speaker 3: which are in the surface of Ganymede. So these concentric
• 29:00
  Speaker 3: circles which are all centered on a point which is
• 29:03
  Speaker 3: where that impact is thought to have taken place. So
• 29:06
  Speaker 3: there's no crater, but there are these ancient pieces of
• 29:10
  Speaker 3: evidence of there having been an impact, that these concentric
• 29:15
  Speaker 3: circular features which are quite prominent on Ganymede's surface. So
• 29:24
  Speaker 3: I think the eight and South Pole Basin still has
• 29:27
  Speaker 3: the record for the biggest crater, certainly one of the
• 29:32
  Speaker 3: biggest craters in the Solar system. It's two and a
• 29:35
  Speaker 3: half thousand kilometers in diameters, so it's actually bigger than
• 29:39
  Speaker 3: what the Ganymede crater would have been had it still
• 29:42
  Speaker 3: been there.
• 29:44
  Speaker 2: That's amazing.
• 29:45
  Speaker 3: Yes, So it's a big dip in the southern polar
• 29:49
  Speaker 3: region of the Moon and again thought to be due
• 29:52
  Speaker 3: to an asteroid impact perhaps in the very earliest history
• 29:56
  Speaker 3: of the Moon four billion years ago or so.
• 29:59
  Speaker 1: Now what can I can I glean as to how
• 30:03
  Speaker 1: large that asteroid would have been that hit the Moon?
• 30:06
  Speaker 3: Uh? Yes, I can't remember what the figure is though.
• 30:09
  Speaker 3: It's it's it's sort of almost like a planetary body.
• 30:13
  Speaker 3: It's almost a protoplanet or something like that. So several
• 30:16
  Speaker 3: hundred kilometers across probably yeah, Okay. The second part of
• 30:24
  Speaker 3: Ross's question has me very puzzled because he talks about Triton,
• 30:29
  Speaker 3: which is the biggest moon of Neptune, and it it
• 30:37
  Speaker 3: is uh, it's it's just well, what the the what
• 30:47
  Speaker 3: what ROSSI is saying is that it's got a big
• 30:50
  Speaker 3: impact crater on it to make it a very odd shape.
• 30:53
  Speaker 3: But actually Triton's almost perfectly spherical. So I'm not quite
• 30:57
  Speaker 3: sure what is thinking of and whether he and I
• 31:01
  Speaker 3: are at cross purposes here, whether he's thinking of another object.
• 31:05
  Speaker 3: But Triton is a very well behaved moon. It's in
• 31:08
  Speaker 3: terms of its shape, it's pretty spherical. It's a large moon.
• 31:12
  Speaker 3: It's unusual in that it orbits Neptune backwards. It's what's
• 31:18
  Speaker 3: called a retrograde orbit. It's clockwise a scene from above
• 31:21
  Speaker 3: the North Pole, which is backwards compared with the rest
• 31:24
  Speaker 3: of the Solar System, and so it's it's probably was
• 31:28
  Speaker 3: once a dwarf planet in the Koiker Belt. So it's
• 31:31
  Speaker 3: something that's been captured by the gravity of Neptune. But
• 31:36
  Speaker 3: it is nicely circular, nicely spherical. So not sure about
• 31:41
  Speaker 3: the impact crater. We might talk too Rusty again about that.
• 31:45
  Speaker 1: Yeah, he's not. I'm not sure he'll ever send a
• 31:49
  Speaker 1: question in again. But if he does, he can, he
• 31:53
  Speaker 1: can he can follow us up and provide more clarity.
• 31:59
  Speaker 1: I think we'll say I just looked it up. The
• 32:01
  Speaker 1: South Polar acn basin on the Moon impact crater. Yeah,
• 32:07
  Speaker 1: you said two and a half thousand kilometers, the biggest
• 32:09
  Speaker 1: in the Solar system. The object they think was about
• 32:12
  Speaker 1: two hundred kilometers in diameter. That's a bit hit on
• 32:16
  Speaker 1: a small moon.
• 32:17
  Speaker 2: It is type of situation. Yeah, made a bit of
• 32:20
  Speaker 2: a mess by the sound of it. Rusty, thank you.
• 32:23
  Speaker 2: If you want to kind of come back to us.
• 32:26
  Speaker 1: Yeah, by all means, send us a bit more info
• 32:29
  Speaker 1: so that we can revisit that question and don't forget.
• 32:33
  Speaker 1: If you've got a question for us, send us in
• 32:35
  Speaker 1: because we are a bit short, because I did a
• 32:37
  Speaker 1: bit of a clean out when I got back and
• 32:40
  Speaker 1: we need some fresh material. So send the questions into
• 32:45
  Speaker 1: us via our website, Spacenuts podcast dot com or space
• 32:48
  Speaker 1: Nuts dot io and just that little AMA link at
• 32:53
  Speaker 1: the top is where you can send text and audio questions,
• 32:56
  Speaker 1: which is pretty easy.
• 32:57
  Speaker 2: If you've got a device with a.
• 32:58
  Speaker 1: Microphone, whether that's a smartphone or a tablet or a computer,
• 33:04
  Speaker 1: send it into us. Don't forget, forget as always to
• 33:07
  Speaker 1: tell us who you.
• 33:07
  Speaker 2: Are and where you're from. We're all done, Fred, Thank
• 33:10
  Speaker 2: you so much.
• 33:11
  Speaker 3: Oh it's been a pleasure as always and always stimulating
• 33:15
  Speaker 3: and good to chat it is.
• 33:17
  Speaker 1: I love it all right, We'll see you soon. Professor
• 33:19
  Speaker 1: Fred Watson, Astronomer at large, and thanks to you in
• 33:22
  Speaker 1: the studio who couldn't be with us today because that's
• 33:26
  Speaker 1: his preferred state. He just doesn't want to be with us.
• 33:31
  Speaker 2: Thanks Hugh, and from me Andrew Uncley, thanks for your company.
• 33:34
  Speaker 1: See you on the very next episode of Space Nuts.
• 33:37
  Speaker 2: By listen to the Space Nuts podcast.
• 33:43
  Speaker 1: Available at Apple Podcasts, Spotify, iHeartRadio, or your favorite podcast player.
• 33:49
  Speaker 2: You can also stream on demand at bides dot com.
• 33:52
  Speaker 2: This has been another quality podcast production from Nights dot com.