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Planetary Orbits, Cosmic Expansion & The Nature of Nothing | Space Nuts Q&A · Space Nuts: Astronomy Insights & Cosmic Discoveries

• 0:00
  Speaker 1: Hi there, Thanks again for joining us. This is Space
• 0:03
  Speaker 1: Nuts a Q and A Edition. My name is Andrew Dunkley,
• 0:06
  Speaker 1: your host. It's good to have your company. A Q
• 0:09
  Speaker 1: and A edition means that people ask us questions and
• 0:13
  Speaker 1: we don't do anything about it except try to answer them.
• 0:18
  Speaker 1: Justin has sent a question in about planetary orbits versus energy.
• 0:23
  Speaker 1: He doesn't quite get what's going on there. Larry is
• 0:27
  Speaker 1: asking about whether or not the Earth is expanding in
• 0:30
  Speaker 1: relation to the universe expanding. Giles wants to talk about
• 0:36
  Speaker 1: solid metal projectiles in a what if question, and Mike
• 0:40
  Speaker 1: wants to talk about nothing for fifteen seconds. Guidance is
• 0:44
  Speaker 1: in channel ten nine ignition sequence Space Nuts Guy or
• 0:51
  Speaker 1: three two one spacenutes as can I report it? Bill's
• 0:58
  Speaker 1: good and back to share his wealth of knowledge with
• 1:02
  Speaker 1: us is Professor Fred Watson, an astronomer at large. Hello Fred, Hello,
• 1:07
  Speaker 1: an't true?
• 1:09
  Speaker 2: That's a nice word.
• 1:10
  Speaker 1: Is wealth?
• 1:10
  Speaker 2: Isn't it wealth?
• 1:11
  Speaker 1: Yes?
• 1:12
  Speaker 2: Yes, the knowledge is fine, but do make you wealthy?
• 1:18
  Speaker 1: No, it doesn't does it does not unless you know
• 1:21
  Speaker 1: what to use it for. Yes, that's right, Yes, never mind,
• 1:28
  Speaker 1: Let's let's get some questions sorted out because we've got
• 1:31
  Speaker 1: a batch of really really good ones again today, and
• 1:35
  Speaker 1: our first question comes from Justin.
• 1:40
  Speaker 3: Hello, Fred and Andrew, it's Justin down in Melbourne. Thank
• 1:43
  Speaker 3: you for answering my first question earlier this year. I
• 1:47
  Speaker 3: have another question now, which relates to the Solar System.
• 1:52
  Speaker 3: We're told that classical physics can't explain the existence of
• 1:55
  Speaker 3: the assom because negatively charged particles orbiting a positive nucleus
• 2:00
  Speaker 3: would lose energy and spiral in towards a nucleus. And
• 2:03
  Speaker 3: of course we need quantum mechanics to explain the atom stability.
• 2:07
  Speaker 1: But by extension, I was thinking about the Solar system.
• 2:10
  Speaker 3: How is it that the planets maintain orbits around the
• 2:13
  Speaker 3: Sun without losing energy and spiraling in towards the Sun.
• 2:17
  Speaker 3: If you think about that classic demonstration with the rubber
• 2:20
  Speaker 3: sheet and the bowling ball with some marbles, the marbles
• 2:24
  Speaker 3: will orbit the bowling ball, but then very quickly lose
• 2:27
  Speaker 3: energy and find themselves next to the bowling ball. And
• 2:31
  Speaker 3: of course that's due to the friction of the rubber sheet.
• 2:34
  Speaker 3: But I'm assuming there's a frictional component even in interplanetary space.
• 2:40
  Speaker 3: But is it the fact that that really is negligible
• 2:43
  Speaker 3: even on geological time scales and wouldn't cause the planets
• 2:46
  Speaker 3: to lose energy. So perhaps you can walk us through
• 2:49
  Speaker 3: how that works. And my second question is to do
• 2:54
  Speaker 3: with the fact that the planets themselves obviously gravitationally interact,
• 2:58
  Speaker 3: and perhaps there are some resins and is there as
• 3:00
  Speaker 3: well which can cause planets to move either further away
• 3:05
  Speaker 3: from the Sun, as Jupiter is supposed to have done
• 3:09
  Speaker 3: in its lifespan. So, given that the Sun is at
• 3:12
  Speaker 3: the halfway point in its life, do we foresee any
• 3:16
  Speaker 3: radical restructuring or reshuffling of the planets in the Solar
• 3:22
  Speaker 3: System in the Sun's second half of life. I love
• 3:26
  Speaker 3: the podcast and I hope you can share some insights
• 3:29
  Speaker 3: on that one.
• 3:30
  Speaker 1: Thank you. We will do our very best. Actually I
• 3:32
  Speaker 1: won't do anything, thank you, justin I'll end it all
• 3:36
  Speaker 1: over to Fred. So two questions really interesting, both of
• 3:39
  Speaker 1: them planetary orbits versus energy. Why don't they sort of
• 3:43
  Speaker 1: slow down and fall in like you do with the
• 3:45
  Speaker 1: old bowling ball on a rubber mat trick and the
• 3:50
  Speaker 1: planet's reshuffling as the Sun gets older? Will do them separately?
• 3:57
  Speaker 1: It's a good question. I don't know if we've had
• 3:59
  Speaker 1: this one recently. We might have had it before. But
• 4:03
  Speaker 1: what keeps them keeping on for it?
• 4:06
  Speaker 2: Well, they do, They just keep on keeping on. So
• 4:09
  Speaker 2: just Justin's right in that, Yes, the thing that sends
• 4:13
  Speaker 2: the marble down to the bowling ball on the rubber
• 4:16
  Speaker 2: sheet is the friction of the of the rolling phenomenon.
• 4:22
  Speaker 2: All sorts of frictions come in. There's a bit of
• 4:24
  Speaker 2: air braking as well with that, not much, but and
• 4:28
  Speaker 2: that that's what leads to that situation. In the Solar System,
• 4:33
  Speaker 2: there's very little to provide any kind of friction, if
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  Speaker 2: at all. The I mean, the outward pressure of the
• 4:42
  Speaker 2: solar wind is in terms of planetary dynamics, exerts a
• 4:48
  Speaker 2: negligible force that the force actually does affect small objects
• 4:54
  Speaker 2: like asteroids. We've discussed recently how the Sun's red can
• 5:00
  Speaker 2: speed up the spin of asteroids. That's an effect to
• 5:04
  Speaker 2: his name, I can't remember, but that's the case.
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  Speaker 1: So it's.
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  Speaker 2: Essentially a situation where you've you've set these things in
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  Speaker 2: motion and the speed of rotation determined or revolution determined
• 5:20
  Speaker 2: how far away they are from the Sun's We are
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  Speaker 2: in a very stable era in the Solar System, and
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  Speaker 2: I mean, notwithstanding the fact that it seems counterintuitive that
• 5:39
  Speaker 2: they should just be able to go on forever rotating
• 5:41
  Speaker 2: in their orbits to sort of lurch towards the second
• 5:45
  Speaker 2: part of Justin's question. Yes, there probably have been migrations,
• 5:49
  Speaker 2: we believe of planets from one orb bit to another.
• 5:54
  Speaker 2: Things are very very stable, as they are now, incredibly
• 5:56
  Speaker 2: stable we have, yeah, and probably for the second half
• 6:01
  Speaker 2: of the Sun's life, things will remain much as they
• 6:05
  Speaker 2: are now. The Moon's drifting away from the Earth, we
• 6:09
  Speaker 2: know about that. That's because it's losing energy or gaining
• 6:13
  Speaker 2: it sorry, gaining energy from the slow down of the
• 6:15
  Speaker 2: s rotation that pushes it further and further out. But
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  Speaker 2: in terms of the planets, there isn't anything really similar
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  Speaker 2: going on. The Sun's mass is by far the biggest component,
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  Speaker 2: by a huge amount, of the mass of the Solar System,
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  Speaker 2: and Jupiter's mass is by a huge amount the biggest
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  Speaker 2: component of the mass of the planets. So Jupiter certainly
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  Speaker 2: calls the shots, and that's why we've got an asteroid
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  Speaker 2: belt where we have, because it probably Jupiter's gravitational interaction
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  Speaker 2: with the debris disk from which the planets formed probably
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  Speaker 2: sort of stymied the idea of things sticking together. Well,
• 6:53
  Speaker 2: as soon as protoplanets stuck together, they or as planet
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  Speaker 2: Isi wal stuck together, that they got blasted apart by
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  Speaker 2: the gravitational pull of Jupiter and probably collisions as well.
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  Speaker 2: So the history of the Solar System is probably dominated
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  Speaker 2: in its early era by planetary orbits evolving, and that's
• 7:22
  Speaker 2: just because the density of material. There's still a lot
• 7:24
  Speaker 2: of debris left in the dust disk, there's a lot
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  Speaker 2: of collisions carrying taking place, and perhaps some gravitational instabilities
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  Speaker 2: that just needed to get themselves sorted out. Justin mentioned resonances,
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  Speaker 2: and there are many situations like that in the Solar System.
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  Speaker 2: There's a group of asteroids called the Hilda asteroids, which
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  Speaker 2: are in the main asteroid belt, but they have a
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  Speaker 2: resonance with Jupiters. So for every three orbits of a
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  Speaker 2: Hilda asteroid, you get two orbits of Jupiter. So every
• 8:01
  Speaker 2: three a filled and two of Jupiter.
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  Speaker 1: There. Yes, we talked about this before and that didn't
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  Speaker 1: we find some weird ex planet that had like eight planets.
• 8:11
  Speaker 2: Yes, that's right, Yes, that's one. I think that's the Trappist.
• 8:15
  Speaker 2: I think it's one of the trappest planetary systems. Yes,
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  Speaker 2: and it's got that they're all in neat orders because
• 8:21
  Speaker 2: they're all in resonance, and that that's something that's evolved,
• 8:24
  Speaker 2: you know, probably quite early on in the history of
• 8:27
  Speaker 2: that planetary system. You've got this array of planets that
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  Speaker 2: do pull themselves into resonant orbits. Now resident there aren't
• 8:35
  Speaker 2: really resonances between the planets except that Pluto is in
• 8:39
  Speaker 2: resonance with Neptune. I can't remember. That might be three
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  Speaker 2: to two as well, for every three orbits of Neptune
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  Speaker 2: two of Pluto. You might need to check what those
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  Speaker 2: numbers are. But it is a resonance. It's called a
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  Speaker 2: resonant object, and so that's come about over time. Neptune
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  Speaker 2: is much more dominant than Pluto in its gravitational pool, so.
• 9:03
  Speaker 1: It is a three it's a three to two resonance. Yeah.
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  Speaker 2: Yeah, so that's a fairly common one. So, yes, it
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  Speaker 2: does happen. But the way things are now is they're
• 9:14
  Speaker 2: very stable. They've evolved over four point seven billion years,
• 9:17
  Speaker 2: and they're pretty happy with the way things are.
• 9:19
  Speaker 1: I think. Yeah, it's fascinating, isn't it. You mentioned that
• 9:23
  Speaker 1: effect of the Sun on asteroids. There's actually two effects.
• 9:26
  Speaker 1: There's the yorp effect. Yeah, that's the sport in four
• 9:31
  Speaker 1: names four yes, and the Yarkovsky effect, which is where
• 9:35
  Speaker 1: the Sun heats the asteroid up, which causes it to
• 9:40
  Speaker 1: emit heat, which acts as a tiny thruster which accelerates
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  Speaker 1: its orbital speed. Yeah.
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  Speaker 2: But these are you know, these are the tiny bodies
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  Speaker 2: of the Solar System. So they're they're orbits are evolving,
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  Speaker 2: that suggests, but they very much the you know, they're
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  Speaker 2: not planets.
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  Speaker 1: No, definitely not. So there's basically nothing stopping the planets
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  Speaker 1: from just doing what they're doing forever until the Sun
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  Speaker 1: gives up and says all right, I've had enough of
• 10:09
  Speaker 1: you lot and gets too big for itselves. Yes, so
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  Speaker 1: nothing to worry about. Justin, you can go to work tomorrow.
• 10:16
  Speaker 1: Oh I heard him say, thanks for the question. Justin.
• 10:19
  Speaker 1: Lovely to hear from you. Our next question comes from Larry.
• 10:24
  Speaker 1: I know we've been down this road before, actually, but
• 10:26
  Speaker 1: it's a great question. Larry asks, is space. If space
• 10:31
  Speaker 1: is expanding, then is the Earth also expanding? By how much?
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  Speaker 1: And would it be measurable?
• 10:38
  Speaker 4: Now?
• 10:39
  Speaker 1: I seem to remember a conversation we had a long
• 10:41
  Speaker 1: time ago about the fact that as the universe expands,
• 10:45
  Speaker 1: everything's expanding with it and moving further and further away,
• 10:49
  Speaker 1: and we're going to reach a point where it will
• 10:51
  Speaker 1: expand so much that we won't be able to see
• 10:53
  Speaker 1: anything because everything we're just too far away for the
• 10:55
  Speaker 1: light to reach us. But I think I did ask
• 10:58
  Speaker 1: you the question as to whether or not my next
• 11:00
  Speaker 1: door neighbor's house will be moving away from me, and
• 11:03
  Speaker 1: the answer was yes, wasn't it.
• 11:05
  Speaker 2: No, it's no, it's no right, you stuck with them,
• 11:08
  Speaker 2: I'm afraid. Yeah, so you're right that the space occupied
• 11:16
  Speaker 2: by the Earth is expanding, but it's you know, it's
• 11:22
  Speaker 2: not even microscopic, it's a sub atomic level over even
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  Speaker 2: geological lifetimes, probably because it's such a small distance. The
• 11:32
  Speaker 2: universe is very, very big and might long way to
• 11:37
  Speaker 2: the exactly chemist shop. Yeah, that's twice we've had Douglas
• 11:43
  Speaker 2: Adams been worth quoting. Yes, in recent weeks. I was
• 11:49
  Speaker 2: going to say, yes, they are worth quoting. So it's
• 11:53
  Speaker 2: it's you only really see the expansion when you start
• 11:56
  Speaker 2: looking out millions of light years. Then you do, as
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  Speaker 2: discovered back in nineteen twenty nine. But the reason why
• 12:04
  Speaker 2: the Earth is not participating in that expansion. Is that
• 12:08
  Speaker 2: the forces that hold atoms together and that holds the
• 12:12
  Speaker 2: Earth together, which is certainly gravity in terms of keeping
• 12:15
  Speaker 2: the Earth together, is by far the dominant force. So
• 12:19
  Speaker 2: the Earth's self gravity is easily enough to basically to
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  Speaker 2: overcome any tendency of the space within which the Earth
• 12:29
  Speaker 2: sits to expands. On the scale of the Solar System,
• 12:34
  Speaker 2: you can forget the cosmic expansion. In fact, on the
• 12:37
  Speaker 2: scale of our galaxy, you can forget it.
• 12:39
  Speaker 1: Basically.
• 12:41
  Speaker 2: It's only when you start looking at more distant galaxies
• 12:44
  Speaker 2: that you start seeing any measurable velocity change.
• 12:47
  Speaker 1: Okay, so yep, gravity overcomes all. Yes, So sorry, Larry,
• 12:53
  Speaker 1: You're stuck with your neighbors as I am with mine.
• 12:55
  Speaker 1: It's just just the way it is. Earth will hold
• 12:59
  Speaker 1: itself together. We are tough. Good question, though, good question,
• 13:05
  Speaker 1: and is I was going to say, yeah, if you
• 13:10
  Speaker 1: do want to said his questions, you can do so
• 13:11
  Speaker 1: on our website and I'll tell you about that at
• 13:14
  Speaker 1: the end of the show. This is Space Nuts with
• 13:16
  Speaker 1: Andrew Dunkley and Professor Fred Watson. The crew of.
• 13:22
  Speaker 3: Artemis two now bound for the Moon, Humanity's next Great
• 13:26
  Speaker 3: Voyage begins space Nuts.
• 13:29
  Speaker 1: Our next question, Fred is going to be a quick
• 13:32
  Speaker 1: one because basically it's about nothing.
• 13:36
  Speaker 2: No.
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  Speaker 4: This is Mike from Cromer in the UK. You had
• 13:42
  Speaker 4: a question, Well, i'm podcast, I'm listening to the beginning
• 13:47
  Speaker 4: of the universe as in the Big Bang, referred to
• 13:50
  Speaker 4: it as being nothing before it, Shirley, from a non
• 13:57
  Speaker 4: science point of view, it be better to say there
• 14:01
  Speaker 4: was something before the Big Bang, but you don't know
• 14:05
  Speaker 4: what it was. Why do you refer it refer to
• 14:10
  Speaker 4: it as nothing before the Big Bang? It was trans question,
• 14:15
  Speaker 4: but I thought i'd ask cheers.
• 14:18
  Speaker 1: Thank you, Mike. I think it was me that said
• 14:22
  Speaker 1: that we thought there was nothing before the Big Bang,
• 14:24
  Speaker 1: and I think your answer was now it wasn't nothing,
• 14:27
  Speaker 1: it's we don't know. Is that right? Or am I
• 14:30
  Speaker 1: getting crossed up with something?
• 14:32
  Speaker 2: And I mean that's right as well?
• 14:36
  Speaker 1: That the issue, yes, so that.
• 14:39
  Speaker 2: The standard line is in the beginning there was nothing
• 14:43
  Speaker 2: and then it exploded. That's you know, that's a standard line,
• 14:48
  Speaker 2: and that's very glib. The issue I have with trying
• 14:52
  Speaker 2: to explain this is not with the word nothing or
• 14:55
  Speaker 2: even with the word something, which is what Mike would
• 14:59
  Speaker 2: prefer something, but we don't know what it was. But
• 15:02
  Speaker 2: the issue I have is with the word before, because
• 15:07
  Speaker 2: our understanding of the universe, certainly as far as relativity,
• 15:11
  Speaker 2: informs us the models that you can build that you
• 15:15
  Speaker 2: can build Time started with the Big Bang. Now, that
• 15:19
  Speaker 2: is the prevalent, prevalent theory, but it is only one theory.
• 15:23
  Speaker 2: There are others that do suggest that there was something
• 15:26
  Speaker 2: before the Big Bang. Roger Penrose is one of the
• 15:29
  Speaker 2: proponents of that sort of thing. But the kind of
• 15:32
  Speaker 2: classical relativistic theory of the origin of the universe is
• 15:37
  Speaker 2: that it's not that there was nothing before the Big Bang,
• 15:43
  Speaker 2: it's that there was no time, and so before is
• 15:46
  Speaker 2: not defined. Before has no meaning if you've before, only
• 15:52
  Speaker 2: has meaning if you're in a time domain, and time
• 15:56
  Speaker 2: the start of the universe may be created time as
• 15:59
  Speaker 2: well as space. And that sort of ties in with
• 16:03
  Speaker 2: some of the theories that are upcoming now from which
• 16:06
  Speaker 2: you and I have talked about. The idea that time
• 16:09
  Speaker 2: is an illusion really is an illusion that emerges from
• 16:13
  Speaker 2: a much deeper level by quantum entanglement. That's the thinking.
• 16:18
  Speaker 2: I'm not clear in my own head how these things
• 16:20
  Speaker 2: link together, but it's certainly a very interesting possibility. And
• 16:25
  Speaker 2: so that you know the idea that before the Big Bang, that.
• 16:31
  Speaker 1: There was no before.
• 16:34
  Speaker 2: Before the Big Bank because time didn't exist, then that
• 16:37
  Speaker 2: would seem to be a possibility, given that we're looking
• 16:40
  Speaker 2: for a deeper theory that explains the existence of the universe,
• 16:45
  Speaker 2: in which time is not really a player. Time comes
• 16:47
  Speaker 2: up as an illusion rather than a real thing. It's
• 16:52
  Speaker 2: fascinating stuff. A lot of it's, as Mike says, it's
• 16:56
  Speaker 2: almost into philosophy rather than rather and science. But the
• 17:01
  Speaker 2: scientists are working hard on it. I'm really interested in
• 17:04
  Speaker 2: this stuff because I think you know, Einstein himself was
• 17:09
  Speaker 2: convinced that times in illusion, and he wrote something to
• 17:13
  Speaker 2: that effect to a widow of one of his best
• 17:16
  Speaker 2: friends who just died. It said time is a stubbor.
• 17:20
  Speaker 1: It wasn't.
• 17:20
  Speaker 2: He said, the idea of past, present, and future is
• 17:24
  Speaker 2: a stubbornly persistent illusion.
• 17:27
  Speaker 1: That was that.
• 17:28
  Speaker 2: Those were his words in his letter.
• 17:30
  Speaker 1: Yeah, I've read a theory a while back that suggested
• 17:34
  Speaker 1: that all of time overlaps and that everything we know
• 17:41
  Speaker 1: exists simultaneously.
• 17:42
  Speaker 2: Yeah, that's that's what comes out of relativity. That's the
• 17:46
  Speaker 2: Einstein view exactly that, and it comes from the fact
• 17:51
  Speaker 2: that we realized very shortly after Hubbell, sorry, after Einstein
• 17:57
  Speaker 2: developed his special theory of relativity in ninety one hundred
• 18:00
  Speaker 2: and five, there was a mathematician who kind of unpicked
• 18:05
  Speaker 2: the details, and it was from there that we realized
• 18:08
  Speaker 2: that time is actually a dimension which behaves a little
• 18:12
  Speaker 2: bit like space, because you can bend time. Relativity bends time,
• 18:17
  Speaker 2: and that's one of the things that tells you that
• 18:18
  Speaker 2: it's probably not a very deep and fundamental thing. And
• 18:23
  Speaker 2: so Einstein's view of the universe was exactly what you've
• 18:27
  Speaker 2: just elucidated, the idea of that everything back, past, present,
• 18:32
  Speaker 2: and future all exists in some way, and our sort
• 18:37
  Speaker 2: of gradual progress through them from past to future is
• 18:41
  Speaker 2: the bit that's an illusion. It has a name that
• 18:44
  Speaker 2: is called the block time theory of the universe. It's
• 18:47
  Speaker 2: sort of time is all is in a single block,
• 18:51
  Speaker 2: if I can put it that way, and we just
• 18:52
  Speaker 2: stepped through it from moment to moment, but it all exists.
• 18:55
  Speaker 1: Yeah. There's another element to that, which we've also talked
• 18:59
  Speaker 1: about before, and that is that our existence is a
• 19:04
  Speaker 1: manifestation of our own what our lives are what our
• 19:10
  Speaker 1: world is, what our planet, what our universe is, is
• 19:13
  Speaker 1: a manifestation of ours we I don't know how they
• 19:18
  Speaker 1: come to that concept, but that's another theory that's been
• 19:22
  Speaker 1: put forward, that none of this is real. We've just
• 19:25
  Speaker 1: created it in our minds.
• 19:27
  Speaker 2: Yeah, which tells you that a consciousness might be a
• 19:31
  Speaker 2: fundamental part of the universe. And if it took the
• 19:35
  Speaker 2: universe several billion years to evolve creatures that had consciousness
• 19:41
  Speaker 2: and what was happening before that.
• 19:44
  Speaker 1: Maybe we were just living a giant mind. We just
• 19:47
  Speaker 1: made it all up or a big black hole. That's
• 19:49
  Speaker 1: another ye.
• 19:52
  Speaker 2: But thanks for that, Mike, trying to get these things
• 19:55
  Speaker 2: sorted out in our heads. And yeah, chrome is quite
• 19:58
  Speaker 2: a nice part of the world if I remember rightly,
• 20:00
  Speaker 2: a bit to the Isle of Wight, but that's where
• 20:01
  Speaker 2: it is.
• 20:02
  Speaker 1: Wonderful. Thank you, Mike. Very thought provoking. We love those
• 20:05
  Speaker 1: kinds of questions.
• 20:09
  Speaker 4: Three space nuts.
• 20:14
  Speaker 1: Our final question today comes from Giles. This is really
• 20:19
  Speaker 1: interesting as well. This is a what if high from
• 20:21
  Speaker 1: England Andrew and fred. A popular idea in science fiction
• 20:25
  Speaker 1: when dealing with objects in fixed orbits, such as space
• 20:28
  Speaker 1: stations or planetary targets, is simply to fire big rocks
• 20:32
  Speaker 1: at them from a ship elsewhere in the system. What
• 20:35
  Speaker 1: sort of accuracy could we currently hope to achieve with
• 20:39
  Speaker 1: a simple shaped, solid metal projectile fired from low earth orbit,
• 20:45
  Speaker 1: dropping through the atmosphere, assuming no corrective adjustments after launch,
• 20:51
  Speaker 1: Could we, for instance, landscape London or would we be
• 20:56
  Speaker 1: lucky to hit something in the city of England. Ume
• 21:00
  Speaker 1: hitting a target in orbit would be much easier to achieve. Giles, Now,
• 21:05
  Speaker 1: before you answer this, Fred, it's really interesting that he
• 21:08
  Speaker 1: brings that up because I am currently reading a John
• 21:12
  Speaker 1: Birmingham series called World War three point two and it's
• 21:17
  Speaker 1: called subtitle The Access of Time. John Birmingham's from the UK,
• 21:22
  Speaker 1: but he's living in Australia, up in Queensland.
• 21:28
  Speaker 2: What's did a gig with him? Yeah?
• 21:29
  Speaker 1: A lovely guy and he writes beautifully. I love his books,
• 21:33
  Speaker 1: highly recommend them if you're into science fiction. And in
• 21:39
  Speaker 1: this series there were three books and he enjoyed writing
• 21:41
  Speaker 1: them so much he wrote three more books, which were
• 21:44
  Speaker 1: just novel atts and then he announced, look, I'm going
• 21:48
  Speaker 1: to keep going. This is just too much fun. And
• 21:50
  Speaker 1: he's written three more books and he's now announced he's
• 21:52
  Speaker 1: going to keep going again on this series. It's got
• 21:56
  Speaker 1: some great characters in it, including Prince Harry, who's actually
• 21:59
  Speaker 1: one of the main characters of the story. You've got
• 22:02
  Speaker 1: to remember that Prince Harry was thrust back in time
• 22:05
  Speaker 1: to World War Two with the rest of a fleet
• 22:07
  Speaker 1: and so on and so forth. There's time travel in
• 22:09
  Speaker 1: and all that. But what's interesting is in those novelettes
• 22:13
  Speaker 1: in between, they were trying to rescue a scientist, a
• 22:18
  Speaker 1: rocket scientist or a nuclear scientist, to try and stop
• 22:22
  Speaker 1: Russia from getting a nuclear weapon, and et cetera, et cetera.
• 22:26
  Speaker 1: As a part of that, Stalin decides to lash out
• 22:31
  Speaker 1: against the Allies in Europe and attacks them with tungsten
• 22:37
  Speaker 1: spears fired from a weapons platform in orbit and obliterates
• 22:42
  Speaker 1: the NATO forces. So that's exactly what Giles is talking about. Yeah,
• 22:50
  Speaker 1: and they even though it's not a nuclear weapon, the effect,
• 22:54
  Speaker 1: from what John writes in his novels, the effect is
• 22:58
  Speaker 1: the same it probably was.
• 23:01
  Speaker 2: Yeah, I mean, it's you know, just turling things down,
• 23:05
  Speaker 2: whether it's got explosive in it or not.
• 23:10
  Speaker 1: That's right.
• 23:10
  Speaker 2: You've got enough enough momentum in order to when you
• 23:15
  Speaker 2: convert that to energy in order to make a big impact,
• 23:19
  Speaker 2: which is why we lost the dinosaurs back in the day,
• 23:22
  Speaker 2: same explosion, explosion from that, so, I think Giles's question
• 23:26
  Speaker 2: is how well you could control that, and he's right
• 23:30
  Speaker 2: in that from you know, firing an object from orbit
• 23:34
  Speaker 2: from one place to another is straightforward because the dominant
• 23:40
  Speaker 2: feature there is the interaction of the object with gravity,
• 23:45
  Speaker 2: and it's the you know, gravity generally in the Solar
• 23:48
  Speaker 2: System from the Sun and the planets, and that's highly predictable.
• 23:51
  Speaker 2: And of course we had a dead on bulls eye
• 23:55
  Speaker 2: hit with the Dart spacecraft on Dimorphous back in twenty
• 24:01
  Speaker 2: twenty two that I think I can't remember. It was
• 24:03
  Speaker 2: within just a few meters of the target, and that's
• 24:05
  Speaker 2: because it's easy to do that with high precision. I
• 24:09
  Speaker 2: guess when you're putting something down to the Earth's surface
• 24:12
  Speaker 2: from orbit, you've got the vagaries of the atmosphere to
• 24:16
  Speaker 2: deal with, and so you've got winds which are probably
• 24:21
  Speaker 2: having some influence at different levels. You're still talking about
• 24:25
  Speaker 2: very high velocities though, so they would you know, for
• 24:28
  Speaker 2: your descending object, the winds would have some effect, but
• 24:32
  Speaker 2: maybe not as much as you would think. We're now
• 24:37
  Speaker 2: entering an era of hypersonic missile technology which could be
• 24:43
  Speaker 2: launched from orbit, and those things are very high speed
• 24:48
  Speaker 2: vehicles that can be steered in atmosphere. That's why they're
• 24:52
  Speaker 2: different from ballistic missiles, which followed just the laws of
• 24:56
  Speaker 2: gravity and a bit of atmospheric interaction, so you can
• 25:01
  Speaker 2: kind of work out where they're going to land or
• 25:03
  Speaker 2: where they're going to come in and intercept them. With
• 25:06
  Speaker 2: defensive missiles. That doesn't hold true for hypersonics because they
• 25:09
  Speaker 2: can steer to get out of the way. I don't
• 25:12
  Speaker 2: know why I thought of that, but it's just you know,
• 25:14
  Speaker 2: this business of of how you target something, the atmosphere
• 25:18
  Speaker 2: is going to make a difference.
• 25:20
  Speaker 1: Yeah, I imagine it would. But what Joseph Stalin did
• 25:25
  Speaker 1: to overcome that problem was saturation bombing, Yeah, from strace
• 25:31
  Speaker 1: with tungsten spears. So it didn't matter if this is
• 25:35
  Speaker 1: in the book, this is in the pot. His solution
• 25:38
  Speaker 1: or his scientists solution for lack of accuracy was multiple spears.
• 25:45
  Speaker 2: Basically, well in a way that was you know, wars
• 25:49
  Speaker 2: were fought with bows and arrows, that sort of thing.
• 25:52
  Speaker 1: Yeah, yeah, because bows and arrows weren't all that accurate
• 25:57
  Speaker 1: over distance, but over the Yeah, you fire enough of them,
• 26:01
  Speaker 1: they're going to hit something. Yeah, that's yeah, that's an
• 26:06
  Speaker 1: interesting story in itself, the history of bows and arrows
• 26:08
  Speaker 1: and how the English defeated the French at art and
• 26:11
  Speaker 1: Core using the longbow. Wasn't it that? The ones and
• 26:17
  Speaker 1: that was the end. That was the end of the
• 26:18
  Speaker 1: Nights era of medieval times because the Knights became redundant.
• 26:23
  Speaker 1: Their armor couldn't stop the longbow. As far as I
• 26:27
  Speaker 1: understand it, Yes, yeah, it's fascinating stuff and love that question, Giles,
• 26:33
  Speaker 1: But yes, in real terms, it's too easy to do
• 26:39
  Speaker 1: what you suggest. It really is too easy. And I'm
• 26:44
  Speaker 1: sure these kinds of ideas are bouncing around in the
• 26:47
  Speaker 1: halls of secret buildings somewhere around the world. Anyway, thanks
• 26:52
  Speaker 1: for the question. If you have questions for us, please
• 26:54
  Speaker 1: go to our website. It is space nuts podcast dot
• 26:56
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• 26:59
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• 27:02
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• 27:06
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• 27:09
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• 27:11
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• 27:13
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• 27:15
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• 27:18
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• 27:22
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• 27:24
  Speaker 1: reviews for us wherever you listen to us and we
• 27:27
  Speaker 1: appreciate that in advance. Thank you and thank you Fred.
• 27:30
  Speaker 1: As always, We'll see you next time.
• 27:33
  Speaker 2: Hi, hope, will you do it?
• 27:34
  Speaker 1: So?
• 27:34
  Speaker 2: Even if time is an illusion, it's still nice to
• 27:37
  Speaker 2: go from one week to the next.
• 27:39
  Speaker 1: It is, it is indeed all right. Thanks Red Professor
• 27:43
  Speaker 1: Fred Watson, Astronomer at Large, and thanks to Hue in
• 27:45
  Speaker 1: the studio who was going to join us today but
• 27:48
  Speaker 1: we got nothing. And from me Andrew Dunkley, thanks to
• 27:52
  Speaker 1: your company. We'll see you on the next episode of
• 27:53
  Speaker 1: Space That's bye bye. You'll be listening to the Space
• 27:58
  Speaker 1: Nuts podcast available at Apple Podcasts, Spotify, iHeartRadio, or your
• 28:05
  Speaker 1: favorite podcast player. You can also stream on demand at
• 28:08
  Speaker 1: bytes dot com. This has been another quality podcast production
• 28:13
  Speaker 1: from bites dot com.