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Q&A: Cosmic Queries and What If Scenarios In this thought-provoking episode of Space Nuts, hosts Andrew Dunkley and Professor Fred Watson dive into a range of intriguing questions posed by our curious listeners. From the mysteries of small celestial bodies to the hypothetical survival of humanity's legacy, this episode explores the cosmos through the lens of imagination and scientific inquiry.
Episode Highlights:
- Small Bodies in the Solar System: Bill's question about why small bodies aren't all fluffy leads to a fascinating discussion on the formation of planets and the role of gravity in shaping these celestial objects.
- Leaving a Legacy:Peter's thought-provoking "what if" scenario about leaving something behind after Earth's destruction sparks a conversation about the Voyager spacecraft and humanity's enduring mark on the universe.
- Saturn's Moons and Rings: Martin asks about the minimum size for an object to be classified as a moon, leading to an exploration of Saturn's numerous satellites and the dynamics of its iconic ring system.
- Impact of a Space Station: Finn's imaginative query about a giant space station's effect on the Earth and Moon orbits prompts a discussion on gravitational dynamics and the stability of planetary systems.
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Stay curious, keep looking up, and join us next time for more stellar insights and cosmic wonders. Until then, clear skies and happy stargazing.
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- Formation of Small Celestial Bodies
- Humanity's Cosmic Legacy
- Saturn's Moons and Ring Dynamics
- Gravitational Effects of Space Structures
- Listener Questions and Cosmic Curiosities
00:00:00 --> 00:00:02 Andrew Dunkley: Hi there. Thanks for joining us. This is a Q
00:00:02 --> 00:00:05 and A edition of Space Nuts. Not only do
00:00:05 --> 00:00:07 we talk astronomy and space science, we
00:00:07 --> 00:00:09 pretend to answer questions from our
00:00:09 --> 00:00:11 wonderful, uh, audience. We've got a bunch
00:00:11 --> 00:00:14 today. Bill, uh, is asking about small
00:00:14 --> 00:00:16 bodies in solar systems.
00:00:17 --> 00:00:19 I don't think that's got anything to do with
00:00:19 --> 00:00:21 weight loss, but we'll see. Uh, Peter is
00:00:21 --> 00:00:23 asking about, uh, leaving something behind
00:00:23 --> 00:00:25 that could survive the destruction of Earth.
00:00:26 --> 00:00:29 Wow, that's a what if question. Tiny moons
00:00:29 --> 00:00:32 and giant planets and issues with a
00:00:32 --> 00:00:34 giant space station. Those are, uh,
00:00:34 --> 00:00:36 questions we will endeavour to answer today
00:00:36 --> 00:00:39 on this edition of Space Nuts.
00:00:39 --> 00:00:41 Professor Fred Watson: 15 seconds. Guidance is internal.
00:00:42 --> 00:00:44 10, 9. Ignition
00:00:44 --> 00:00:47 sequence start. Space Nuts. 5, 4,
00:00:47 --> 00:00:50 3, 2. 1. 2, 3, 4, 5, 5,
00:00:50 --> 00:00:52 4, 3, 2, 1. Space Nuts
00:00:52 --> 00:00:54 astronauts report it feels good.
00:00:56 --> 00:00:58 Andrew Dunkley: And with us again is Professor Fred Watson
00:00:58 --> 00:01:00 Watson, um, astronomer at large. Hello,
00:01:00 --> 00:01:00 Fred Watson.
00:01:00 --> 00:01:03 Professor Fred Watson: Hello, Andrew. Uh, fancy seeing you here.
00:01:03 --> 00:01:05 Andrew Dunkley: Yes, unusual. Both wearing black.
00:01:05 --> 00:01:07 Professor Fred Watson: Is it black? Uh,
00:01:08 --> 00:01:09 it is, yeah.
00:01:11 --> 00:01:14 It's the, um, this is the, the shirt
00:01:14 --> 00:01:17 that if I have Jordy sitting on my lap, you,
00:01:17 --> 00:01:20 you can't see him at all because it's exactly
00:01:20 --> 00:01:22 the same colour as he is. Jet black.
00:01:23 --> 00:01:25 Andrew Dunkley: Uh, that'll make a good Instagram photo.
00:01:25 --> 00:01:28 Professor Fred Watson: Well, it might do. Just two eyes poking
00:01:28 --> 00:01:28 out.
00:01:29 --> 00:01:32 Andrew Dunkley: Now, um, we've got a lot to get through, so
00:01:32 --> 00:01:34 we'll start straight away with, uh, a
00:01:34 --> 00:01:36 question that comes from Bill
00:01:37 --> 00:01:40 and he asks if small bodies in the solar
00:01:40 --> 00:01:43 system formed by accretion of fine dust
00:01:43 --> 00:01:46 and gas, why are they not all
00:01:46 --> 00:01:48 fluffy, low gravity powder
00:01:48 --> 00:01:51 puffs? Um, we're
00:01:51 --> 00:01:54 all dense stony. Uh, or, uh, were
00:01:54 --> 00:01:56 all dense stony or metallic objects
00:01:56 --> 00:01:59 originally part of a larger body that could,
00:01:59 --> 00:02:01 could differentiate under, uh, decent
00:02:01 --> 00:02:04 gravity levels, then were smashed to small
00:02:04 --> 00:02:07 pieces in collisions. Uh, thanks for the
00:02:07 --> 00:02:09 great podcasts. Uh, that comes from Bill.
00:02:10 --> 00:02:12 Um, so, yeah, why isn't everything
00:02:12 --> 00:02:13 puffy?
00:02:14 --> 00:02:17 Professor Fred Watson: Um, I think it was to start with. Well, there
00:02:17 --> 00:02:18 you go. Yeah. So,
00:02:20 --> 00:02:22 um, people often say,
00:02:23 --> 00:02:26 people who should know better often say that
00:02:26 --> 00:02:28 if you want to know how planet formation
00:02:28 --> 00:02:30 starts, look under your bed because
00:02:32 --> 00:02:34 the bits of fluff that you tend to find under
00:02:34 --> 00:02:37 your bed are, uh, made of dust
00:02:37 --> 00:02:39 sticking together, uh, usually by
00:02:39 --> 00:02:42 electrostatic forces, which we think played a
00:02:42 --> 00:02:45 part in the early, uh, evolution of planets.
00:02:45 --> 00:02:48 Uh, these things stick together. You build
00:02:48 --> 00:02:51 up bigger and bigger fluff balls. Um,
00:02:51 --> 00:02:54 and eventually the
00:02:54 --> 00:02:57 fluff balls, because. Exactly,
00:02:57 --> 00:03:00 um, as Bill says, they do tend to collide
00:03:00 --> 00:03:02 with one another. We're now talking about a
00:03:02 --> 00:03:05 very, a very, very
00:03:05 --> 00:03:07 dense, dusty environment. We're talking about
00:03:07 --> 00:03:10 the protoplanetary disc that Surrounded the
00:03:10 --> 00:03:13 sun. Uh, very dusty place
00:03:13 --> 00:03:16 with lots of, um, basically
00:03:16 --> 00:03:19 lots of capacity for uh, dust
00:03:19 --> 00:03:22 fluff balls to build up to have bigger and
00:03:22 --> 00:03:24 bigger sizes. Eventually
00:03:25 --> 00:03:27 these various forces uh, will
00:03:27 --> 00:03:30 cause the dust balls to sort of
00:03:30 --> 00:03:33 collapse. Probably collisions will contribute
00:03:33 --> 00:03:36 to, um, by that I mean that they
00:03:36 --> 00:03:39 tend to lose their porosity. In other words,
00:03:39 --> 00:03:41 they become more solid.
00:03:41 --> 00:03:44 Um, now having said that, there are objects
00:03:44 --> 00:03:47 in space that we know are very
00:03:47 --> 00:03:47 porous.
00:03:48 --> 00:03:51 Andrew Dunkley: Um, well we've found powder puff planets,
00:03:51 --> 00:03:51 haven't we?
00:03:52 --> 00:03:54 Professor Fred Watson: Yes, that's right. Uh, yes, almost exactly
00:03:55 --> 00:03:57 a good description of them. I'm just thinking
00:03:57 --> 00:04:00 more nearer to home though. Um, uh,
00:04:00 --> 00:04:03 uh, Phobos, the larger moon of Mars,
00:04:03 --> 00:04:06 is thought to have a composition a bit like
00:04:07 --> 00:04:09 um. God, the word's gone.
00:04:09 --> 00:04:12 Uh, stuff that forms when
00:04:12 --> 00:04:14 eruptions, um, take place
00:04:14 --> 00:04:15 underwater.
00:04:15 --> 00:04:15 Andrew Dunkley: Like a honeycomb.
00:04:16 --> 00:04:19 Professor Fred Watson: Yes, um, but it's got a word. Oh, that's
00:04:19 --> 00:04:21 ridiculous. When you get to a certain age,
00:04:21 --> 00:04:24 words just disappear. It'll come to me
00:04:24 --> 00:04:27 in a minute. I know. Uh, but yeah,
00:04:27 --> 00:04:29 the stuff that floats on the water
00:04:29 --> 00:04:32 underground eruption. Pumice. The very word.
00:04:32 --> 00:04:33 That's what I was looking for. Thank you.
00:04:34 --> 00:04:36 Thank you, Andrew. So pumice is, you know,
00:04:36 --> 00:04:39 it's porous, it's a stony
00:04:39 --> 00:04:42 structure, uh, that's got a lot of gaps in it
00:04:42 --> 00:04:44 and I guess that might well be an
00:04:44 --> 00:04:46 intermediate structure of many of these
00:04:46 --> 00:04:49 objects. Ah, as I said, Phobos is like
00:04:49 --> 00:04:52 that, um, one of Saturn's moons and I
00:04:52 --> 00:04:54 can't remember which one it is, it's the one
00:04:54 --> 00:04:56 shaped like a potato. That'll probably come
00:04:56 --> 00:04:59 to me in a minute as well. Uh, it's also
00:04:59 --> 00:05:01 got that sort of structure. Um, so
00:05:01 --> 00:05:03 maybe, you know, when you get things like
00:05:03 --> 00:05:05 that colour colliding, uh, then
00:05:06 --> 00:05:09 and building up in size, then you're
00:05:09 --> 00:05:11 eventually going to get to this situation
00:05:12 --> 00:05:14 where gravity takes over, uh, and it
00:05:14 --> 00:05:17 pulls um, these low
00:05:18 --> 00:05:20 density materials into something
00:05:20 --> 00:05:21 more solid.
00:05:22 --> 00:05:24 Andrew Dunkley: Um, is it a malthea, A mouth?
00:05:25 --> 00:05:28 Professor Fred Watson: No, uh, it's one with a better known name.
00:05:28 --> 00:05:31 Ah. It's very highly cratered and
00:05:31 --> 00:05:32 potato shaped.
00:05:33 --> 00:05:33 Andrew Dunkley: Ah, okay.
00:05:34 --> 00:05:36 Professor Fred Watson: It's uh, yeah, it's one of the most cratered
00:05:36 --> 00:05:38 objects in the, in the solar system. I'm
00:05:38 --> 00:05:40 annoyed. I can't remember it. It's
00:05:40 --> 00:05:43 ridiculous. I was getting too
00:05:43 --> 00:05:44 old for this, Andrew.
00:05:44 --> 00:05:45 Andrew Dunkley: Oh no you're not.
00:05:45 --> 00:05:46 Professor Fred Watson: No, no, maybe I'm not.
00:05:46 --> 00:05:47 Andrew Dunkley: No, it keeps your brain active.
00:05:48 --> 00:05:51 Professor Fred Watson: Well, except it's demonstrating quite
00:05:51 --> 00:05:53 clearly, uh, that the memory banks are
00:05:53 --> 00:05:56 disappearing. Anyway, um, it'll come to me,
00:05:56 --> 00:05:58 as I said, in a minute. It's not Enceladus,
00:05:58 --> 00:06:01 but it's something like that. Uh, so, uh,
00:06:01 --> 00:06:04 if you've got, you know, gravity taking over,
00:06:04 --> 00:06:06 then you' to get basically solid rock
00:06:06 --> 00:06:09 emerging from that. Uh, uh,
00:06:10 --> 00:06:12 as Bill says, dense, stony or metallic
00:06:12 --> 00:06:14 objects, that's basically what they turn
00:06:14 --> 00:06:17 into. And then they collide. Uh,
00:06:18 --> 00:06:20 um, the larger objects are differentiated.
00:06:20 --> 00:06:22 That means the heavy stuff sinks to the
00:06:22 --> 00:06:24 middle. Uh, exactly as Bill says, but they
00:06:24 --> 00:06:26 collide. And that's how you can get stony
00:06:26 --> 00:06:29 meteorites or metallic
00:06:29 --> 00:06:31 meteorites because the metal tends to sink
00:06:31 --> 00:06:34 mostly, uh, to the middle. So I
00:06:34 --> 00:06:37 think, um, it is a natural process, but it's
00:06:37 --> 00:06:40 one in a way it's counterintuitive to us. You
00:06:40 --> 00:06:42 know, how do you get from a dust, a fluff
00:06:42 --> 00:06:45 ball under your bed. How do you get from that
00:06:45 --> 00:06:46 to a stone to a rock?
00:06:47 --> 00:06:47 Andrew Dunkley: Gravity.
00:06:48 --> 00:06:50 Professor Fred Watson: Yes, that's right, gravity. But over a long
00:06:50 --> 00:06:53 period of time. Uh, and probably heat as
00:06:53 --> 00:06:55 well. You know, you've got heat processes
00:06:55 --> 00:06:57 coming into this too. So, um,
00:06:57 --> 00:07:00 uh, I, uh,
00:07:00 --> 00:07:03 think uh, what um,
00:07:03 --> 00:07:06 Bill's saying is right. If the small bodies
00:07:06 --> 00:07:08 in the solar system formed by accretion of
00:07:08 --> 00:07:10 fine dust and gas, why are they not all
00:07:10 --> 00:07:13 fluffy, low gravity powder puffs? Well, some
00:07:13 --> 00:07:15 of them are and that's. Perhaps you could
00:07:15 --> 00:07:18 describe them like um,
00:07:18 --> 00:07:21 Phobos. Uh, perhaps he could describe them as
00:07:21 --> 00:07:23 unevolved. They haven't evolved much.
00:07:23 --> 00:07:26 I think it might be Hyperion, the one I'm
00:07:26 --> 00:07:26 thinking of.
00:07:26 --> 00:07:27 Andrew Dunkley: Okay.
00:07:28 --> 00:07:29 Professor Fred Watson: I think it might be Hyperion. I'll have a
00:07:29 --> 00:07:32 look, Have a look, See if it's um, shaped
00:07:32 --> 00:07:35 like a potato and got lots of graters on it.
00:07:35 --> 00:07:36 Andrew Dunkley: Yeah. Well, there's got to be a photo of it
00:07:36 --> 00:07:37 somewhere. Yes, it is.
00:07:38 --> 00:07:38 Professor Fred Watson: Yeah.
00:07:38 --> 00:07:38 Andrew Dunkley: Yeah.
00:07:38 --> 00:07:39 Professor Fred Watson: Okay, good.
00:07:39 --> 00:07:41 Andrew Dunkley: It's got, it's got that big, um.
00:07:42 --> 00:07:43 It's got a massive crater in it actually.
00:07:43 --> 00:07:46 Professor Fred Watson: Yeah. Yes, yes. Yeah, yeah.
00:07:46 --> 00:07:47 So, um, so these are you got
00:07:47 --> 00:07:48 Andrew Dunkley: there in the end, Fred Watson.
00:07:48 --> 00:07:51 Professor Fred Watson: In the end? Yeah, it's. Yes. It's just the
00:07:51 --> 00:07:53 processing speeds down a bit. I must be
00:07:53 --> 00:07:56 offline or something like that. Probably need
00:07:56 --> 00:07:59 a reboot. God, don't say that. Might
00:07:59 --> 00:07:59 never come back.
00:08:01 --> 00:08:02 Andrew Dunkley: Well, that's happened. My car did that while
00:08:02 --> 00:08:05 we were away. Uh, came home
00:08:05 --> 00:08:08 and to, uh, to, to stop falling asleep. We
00:08:08 --> 00:08:09 decided we'd go and do the groceries straight
00:08:09 --> 00:08:11 after getting off a long haul flight.
00:08:11 --> 00:08:12 Professor Fred Watson: Oh, yes. Yeah.
00:08:12 --> 00:08:14 Andrew Dunkley: And the car wouldn't start.
00:08:15 --> 00:08:17 Yeah, the battery died, so.
00:08:17 --> 00:08:18 Professor Fred Watson: Oh, the battery died.
00:08:18 --> 00:08:21 Andrew Dunkley: Yeah. That's another 315 bucks. Thank you
00:08:21 --> 00:08:21 very much.
00:08:22 --> 00:08:22 Professor Fred Watson: Yes.
00:08:22 --> 00:08:25 Andrew Dunkley: Anyway, it happens. It was four years. It
00:08:25 --> 00:08:26 lasted four years.
00:08:26 --> 00:08:27 Professor Fred Watson: Oh, that's all right. That's about as long as
00:08:27 --> 00:08:28 you get from a battery.
00:08:28 --> 00:08:31 Andrew Dunkley: Yes, it is indeed. But thanks, Bill, for the
00:08:31 --> 00:08:33 question. Uh, I think you answered it
00:08:33 --> 00:08:35 yourself, but, um, y, uh, although
00:08:35 --> 00:08:37 if you're, um, someone like me,
00:08:38 --> 00:08:40 um, and you don't clean under the bed, uh,
00:08:41 --> 00:08:43 you can watch planets evolve.
00:08:44 --> 00:08:45 That's what's happening.
00:08:46 --> 00:08:47 Professor Fred Watson: Yep, you can.
00:08:47 --> 00:08:48 Andrew Dunkley: All right, uh, thanks, Bill.
00:08:48 --> 00:08:51 Our next question, uh, is
00:08:51 --> 00:08:53 coming from Peter.
00:08:53 --> 00:08:56 Speaker C: Hello, this is Peter in Lamington
00:08:56 --> 00:08:59 Spa. And I want to know
00:09:00 --> 00:09:02 what would it take for
00:09:02 --> 00:09:04 humans to
00:09:05 --> 00:09:08 make something that will survive
00:09:09 --> 00:09:11 the destruction of Earth
00:09:11 --> 00:09:14 and then potentially be incorporated
00:09:15 --> 00:09:18 into a new planet when all the bits of Earth
00:09:18 --> 00:09:20 become a different planet and sometime in the
00:09:20 --> 00:09:22 future, Is it possible?
00:09:24 --> 00:09:27 Andrew Dunkley: Have a good evening. Thank you, Peter. That's
00:09:27 --> 00:09:30 a what if question. Uh, yeah, I wonder.
00:09:30 --> 00:09:33 That's a very. It's a long haul science
00:09:33 --> 00:09:36 fiction situation. You build something
00:09:36 --> 00:09:38 that will survive the destruction of Earth
00:09:38 --> 00:09:40 and then somehow the planet reconstitutes
00:09:40 --> 00:09:43 itself and billions of years later there's an
00:09:43 --> 00:09:45 intelligent race living on the planet and
00:09:45 --> 00:09:47 they go, oh, hello. What's all this then?
00:09:48 --> 00:09:51 Professor Fred Watson: This is some leftover of humankind? Yeah,
00:09:51 --> 00:09:52 whatever they were.
00:09:53 --> 00:09:55 Andrew Dunkley: There was a TV series that I watched many
00:09:55 --> 00:09:58 years ago called Childhood's End, and
00:09:59 --> 00:10:01 it was about the destruction of Earth. And
00:10:02 --> 00:10:04 before it, before it was destroyed,
00:10:05 --> 00:10:08 um, the humans asked the aliens
00:10:08 --> 00:10:11 that rescued the children, basically, um,
00:10:11 --> 00:10:13 can we just leave something behind so they
00:10:13 --> 00:10:15 know we were here? So they left. Music.
00:10:17 --> 00:10:20 Professor Fred Watson: Lovely. I like that. Yes, I like that very
00:10:20 --> 00:10:20 much.
00:10:20 --> 00:10:22 Andrew Dunkley: I just spoiled the whole thing too, by the
00:10:22 --> 00:10:22 way.
00:10:22 --> 00:10:24 Professor Fred Watson: Um, I don't think you did really, uh,
00:10:25 --> 00:10:28 because. Yes, that's a kind of concept, isn't
00:10:28 --> 00:10:31 it, that you're leaving behind? Uh, and
00:10:32 --> 00:10:35 my mind, when I read Peter's question or
00:10:35 --> 00:10:37 heard Peter's question, went to
00:10:38 --> 00:10:41 more concrete things, not necessarily made of
00:10:41 --> 00:10:42 concrete.
00:10:43 --> 00:10:44 Andrew Dunkley: I was about to say that.
00:10:46 --> 00:10:48 Professor Fred Watson: But in a sense we've already done it, Andrew,
00:10:48 --> 00:10:50 because there are five
00:10:52 --> 00:10:55 little spacecraft which are,
00:10:55 --> 00:10:58 ah, absolute, um,
00:10:59 --> 00:11:01 uh, monuments to humanity leaving the
00:11:01 --> 00:11:04 solar system, um, way, way beyond
00:11:04 --> 00:11:07 the orbit of Earth. Voyager 1 is
00:11:07 --> 00:11:10 probably beyond. Actually,
00:11:10 --> 00:11:13 that's not quite true. I, uh, was going to
00:11:13 --> 00:11:15 say beyond the limits of the sun. When it
00:11:15 --> 00:11:17 turns into a red giant star, um,
00:11:19 --> 00:11:21 Voyager 1 will probably survive,
00:11:22 --> 00:11:25 um, the red giant phase of
00:11:25 --> 00:11:28 our sun, uh, which will take place in
00:11:28 --> 00:11:30 a few billion years, three or four
00:11:30 --> 00:11:33 billion years. Um, it'll survive that,
00:11:33 --> 00:11:36 but might not survive the formation of
00:11:36 --> 00:11:39 a planetary nebula when you've got hot gas
00:11:39 --> 00:11:42 coming off the, uh, being puffed off the
00:11:42 --> 00:11:44 surface of the red Giant. It might actually
00:11:44 --> 00:11:47 melt in that because it's because planetary
00:11:47 --> 00:11:49 nebulae get to be light years in diameter.
00:11:49 --> 00:11:52 Uh, our Voyager, uh, is only, well, it's
00:11:52 --> 00:11:54 nearly a light day away. Um, on the other
00:11:54 --> 00:11:57 hand, we've got 3 or 4 billion years to play
00:11:57 --> 00:11:59 with because the sun's not going to do
00:11:59 --> 00:12:01 anything really nasty, um, within that
00:12:01 --> 00:12:04 time. So yes, Voyager 1 will be well out of
00:12:04 --> 00:12:06 the way, probably will survive the
00:12:06 --> 00:12:09 eventual evolution, um, and
00:12:11 --> 00:12:13 uh, final evolutionary stages of the sun when
00:12:13 --> 00:12:16 it actually turns into a white dwarf star. So
00:12:16 --> 00:12:19 yes, uh, those spacecraft, Voyager
00:12:19 --> 00:12:22 1, Voyager 2, Pioneer 10, Pioneer 11,
00:12:22 --> 00:12:25 is that right? And New Horizons,
00:12:25 --> 00:12:27 they're the five that are leaving the solar
00:12:27 --> 00:12:30 system which will probably outlive humanity.
00:12:30 --> 00:12:32 Andrew Dunkley: They probably won't. They probably won't be
00:12:32 --> 00:12:32 the last.
00:12:33 --> 00:12:35 Professor Fred Watson: They won't be the last. No, I think that's
00:12:35 --> 00:12:36 right. Uh, but,
00:12:37 --> 00:12:39 um, I mean
00:12:40 --> 00:12:43 the idea of, um, the Earth, uh,
00:12:43 --> 00:12:46 being destroyed, the
00:12:46 --> 00:12:48 kinds of things that might destroy the Earth,
00:12:48 --> 00:12:50 ah, are first of all, that eventual
00:12:50 --> 00:12:53 evolution of the sun to a red giant star that
00:12:53 --> 00:12:55 will almost certainly melt the Earth because
00:12:57 --> 00:13:00 the Sun's, um, surface, put
00:13:00 --> 00:13:03 it that way, will be, um, a quarter of a
00:13:03 --> 00:13:04 mile from the Earth. And we might be on the
00:13:04 --> 00:13:07 inside of, uh, could even,
00:13:07 --> 00:13:09 uh, overtake the planet Mars. Uh,
00:13:10 --> 00:13:12 so it's hard to imagine how you'd rebuild
00:13:13 --> 00:13:15 the Earth, uh, from the debris that is really
00:13:15 --> 00:13:17 just molecules, uh, because it'll have been
00:13:17 --> 00:13:20 vaporised. Um, so I think, uh,
00:13:21 --> 00:13:23 in addressing this question, you've really
00:13:23 --> 00:13:26 got to think about things that uh, have
00:13:26 --> 00:13:28 left the Earth. And that really basically
00:13:28 --> 00:13:31 pushes your mind to spacecraft. There are
00:13:31 --> 00:13:34 some spacecraft which are, uh, in orbit
00:13:34 --> 00:13:36 around the sun, uh, which
00:13:36 --> 00:13:39 are spacecraft that have been sent
00:13:39 --> 00:13:42 exploring the inner solar system. Mostly
00:13:42 --> 00:13:44 these days we try and get rid of them. We
00:13:44 --> 00:13:47 plunge them, uh, into either, uh, Jupiter or
00:13:47 --> 00:13:49 Saturn. Jupiter in the case of Galileo,
00:13:49 --> 00:13:51 Saturn in the case of Cassini. Uh, those
00:13:52 --> 00:13:55 spacecraft were destroyed purposely so that
00:13:55 --> 00:13:58 they didn't accidentally land on one of the
00:13:58 --> 00:14:00 moons of Jupiter or Saturn and leave microbes
00:14:00 --> 00:14:03 behind. Um, so you're really talking about
00:14:03 --> 00:14:05 something that's left the solar system. And
00:14:05 --> 00:14:07 that leaves those five spacecraft
00:14:07 --> 00:14:09 I've mentioned. And they definitely will
00:14:09 --> 00:14:11 outlast humankind.
00:14:11 --> 00:14:14 Andrew Dunkley: Okay, there you have it, Peter. Um, so we've
00:14:14 --> 00:14:17 already done it kind of, uh, I don't think
00:14:17 --> 00:14:19 you could probably build some kind
00:14:19 --> 00:14:22 of monolith or something that would survive
00:14:22 --> 00:14:24 the red giant phase of
00:14:25 --> 00:14:28 the sun and, and overwhelm Earth. That would
00:14:28 --> 00:14:31 all get destroyed, um, unless you did
00:14:31 --> 00:14:33 it deep down inside. But I don't even Know,
00:14:33 --> 00:14:36 if you could do that, I think a
00:14:36 --> 00:14:38 red giant phase would be pretty cataclysmic,
00:14:38 --> 00:14:39 wouldn't it?
00:14:39 --> 00:14:42 Professor Fred Watson: Yeah. Uh, yes. If your planet's being
00:14:42 --> 00:14:44 vaporised. Your planet's being vaporised. It
00:14:44 --> 00:14:46 is, yeah.
00:14:47 --> 00:14:49 Andrew Dunkley: Indeed. Thank you, Peter. Great to hear from
00:14:49 --> 00:14:52 you. I love what if questions. So, um, thanks
00:14:52 --> 00:14:55 for serving it up. This is Space Nuts with
00:14:55 --> 00:14:57 Andrew Dunkley and Professor Fred Watson
00:14:57 --> 00:14:57 Watson.
00:15:00 --> 00:15:03 Professor Fred Watson: Swiften Tranquilly Base here.
00:15:03 --> 00:15:06 The eagle has landed. Space Nuts.
00:15:06 --> 00:15:08 Andrew Dunkley: Our next question, Fred Watson, comes from
00:15:08 --> 00:15:11 Martin in Heswall. Heswall, is that right?
00:15:11 --> 00:15:13 Professor Fred Watson: Yes, Heswall. Yeah.
00:15:13 --> 00:15:15 Andrew Dunkley: Where's that? I'm going to guess it's the UK
00:15:15 --> 00:15:15 somewhere.
00:15:16 --> 00:15:19 Professor Fred Watson: It is indeed. It's, um, uh, on the Wirral
00:15:19 --> 00:15:21 Peninsula. So if you think of Liverpool,
00:15:21 --> 00:15:23 you've been to Liverpool? I have. And done
00:15:23 --> 00:15:24 the Beatles experience.
00:15:24 --> 00:15:25 Andrew Dunkley: Yes.
00:15:25 --> 00:15:27 Professor Fred Watson: Is that right? Yes. Yeah. Well, across the
00:15:27 --> 00:15:29 River Mersey from Liverpool is the Wirral
00:15:29 --> 00:15:32 Peninsula and Heswall is
00:15:33 --> 00:15:35 one of the towns on that, um, I've said
00:15:35 --> 00:15:38 before, and in fact we've had listener
00:15:38 --> 00:15:40 comments about this, I had a girlfriend once
00:15:40 --> 00:15:43 who lived on the Wirral Peninsula and so I
00:15:43 --> 00:15:45 used to be a very regular visitor there to a
00:15:45 --> 00:15:46 village called Barnston, which was not that
00:15:46 --> 00:15:49 far from Heswall. There you are. All right.
00:15:49 --> 00:15:51 It's very pretty too. It's a pretty village.
00:15:51 --> 00:15:52 Hmm.
00:15:52 --> 00:15:55 Andrew Dunkley: Okay. Just wanted to know where you
00:15:55 --> 00:15:57 were, Martin. So thank you for that. Uh, I
00:15:57 --> 00:15:58 hope, uh, you'll answer this question.
00:15:58 --> 00:16:01 According to Wikipedia, there are, uh, now
00:16:02 --> 00:16:04 known to be 292 satellites,
00:16:05 --> 00:16:07 uh, with confirmed orbits around Saturn.
00:16:07 --> 00:16:10 Presumably, many of these moons are very
00:16:10 --> 00:16:13 small. So is there a minimum size for
00:16:13 --> 00:16:16 an object to be called a moon? And is
00:16:16 --> 00:16:18 there a minimum size for an object to
00:16:18 --> 00:16:20 maintain a stable orbit around a planet?
00:16:21 --> 00:16:24 Uh, as all the giant plan have ring
00:16:24 --> 00:16:27 systems, would the smaller particles just
00:16:27 --> 00:16:30 be absorbed into the rings? Conversely, I
00:16:30 --> 00:16:32 suppose that many objects could be knocked
00:16:32 --> 00:16:34 out of the rings to form independent
00:16:34 --> 00:16:36 satellites that may become permanently
00:16:36 --> 00:16:39 separated from the rings. Will Saturn get,
00:16:39 --> 00:16:42 uh, to 1 moons or more?
00:16:42 --> 00:16:44 Also, uh, can you recommend a website
00:16:45 --> 00:16:47 which has the latest data about, uh, the
00:16:47 --> 00:16:50 solar system, as the numbers vary from one
00:16:50 --> 00:16:53 site to the next, no doubt due to how recent
00:16:53 --> 00:16:56 the information is. Keep up the work. Thanks,
00:16:56 --> 00:16:58 Martin. Um, that's a good question because,
00:16:58 --> 00:17:01 yeah, we know that the ring systems,
00:17:02 --> 00:17:04 um, are full of dust and ice, but they've
00:17:04 --> 00:17:07 also got larger objects that are referred to
00:17:07 --> 00:17:08 regularly as moons.
00:17:10 --> 00:17:12 Professor Fred Watson: Um, it's interesting, this was one of the
00:17:12 --> 00:17:14 exact questions that came up in the Q and
00:17:14 --> 00:17:17 A night, the science in the pub night that we
00:17:17 --> 00:17:20 had on Lord Howe island at the Dark Sky
00:17:20 --> 00:17:20 Festival.
00:17:21 --> 00:17:23 Andrew Dunkley: That was Martin. He was, he was there.
00:17:24 --> 00:17:25 No he probably wasn't.
00:17:26 --> 00:17:28 Professor Fred Watson: Carry on. There was a Martin
00:17:28 --> 00:17:29 there.
00:17:30 --> 00:17:31 Andrew Dunkley: Did he have a British accent?
00:17:32 --> 00:17:35 Professor Fred Watson: Uh no, he's quite Australian but
00:17:35 --> 00:17:38 he's not from Haswell. But yeah, uh,
00:17:38 --> 00:17:41 but interesting coincidence to get the two
00:17:41 --> 00:17:44 and I don't think at the moment there is
00:17:45 --> 00:17:47 a uh limiting size
00:17:48 --> 00:17:51 to differentiate between a ring particle
00:17:52 --> 00:17:54 and a moon. Um
00:17:55 --> 00:17:58 so uh, it
00:17:58 --> 00:18:01 is a great question um how
00:18:01 --> 00:18:03 do you define a moon around a planet which is
00:18:03 --> 00:18:06 festooned with objects orbiting around it
00:18:07 --> 00:18:09 in the form of rings. So we think the rings
00:18:09 --> 00:18:12 of Saturn are uh the debris
00:18:12 --> 00:18:14 of uh probably a satellite
00:18:15 --> 00:18:18 that came within the Roche limit
00:18:18 --> 00:18:21 of the the planet. The Roche limit
00:18:21 --> 00:18:24 being the point at which uh a solid
00:18:24 --> 00:18:27 object can't actually survive within
00:18:27 --> 00:18:30 that distance. In other words that close to
00:18:30 --> 00:18:32 the planet. Um and so
00:18:32 --> 00:18:35 it broke up into lots of small particles.
00:18:36 --> 00:18:39 Probably the biggest ring sized
00:18:40 --> 00:18:42 sorry the biggest ring particles
00:18:43 --> 00:18:46 uh, uh in the region of 10 metres
00:18:47 --> 00:18:49 because the rings themselves are only about
00:18:49 --> 00:18:52 100 metres thick. Yeah it's quite
00:18:52 --> 00:18:52 staggering.
00:18:54 --> 00:18:57 Um and 250 kilometres
00:18:57 --> 00:19:00 in diameter. So yes it's quite a contrast.
00:19:00 --> 00:19:03 Um a sort of blade of material in space is
00:19:03 --> 00:19:05 the way I've always described it. Uh
00:19:07 --> 00:19:09 but some of the smaller satellites of
00:19:09 --> 00:19:12 Saturn and some of them are actually embedded
00:19:12 --> 00:19:15 in the ring system. Uh some of them
00:19:15 --> 00:19:17 are measured in
00:19:18 --> 00:19:20 single digit kilometres so they're not that
00:19:21 --> 00:19:23 much more than
00:19:24 --> 00:19:27 the biggest ring particles and I'm not sure
00:19:27 --> 00:19:30 that there is a definition between the two.
00:19:30 --> 00:19:33 Uh and in a sense you could say that every
00:19:33 --> 00:19:36 solid object within Saturn's rings is a
00:19:36 --> 00:19:38 satellite and so you're then talking about
00:19:38 --> 00:19:41 millions or maybe even billions of
00:19:41 --> 00:19:44 moons of Saturn. Uh it's a great
00:19:44 --> 00:19:46 question and one that I don't have an answer
00:19:46 --> 00:19:49 for and I perhaps ough who have checked it
00:19:49 --> 00:19:51 out in the wake of the question that came uh
00:19:52 --> 00:19:55 at the science in the pub science in the bolo
00:19:55 --> 00:19:58 on Lord Howe island the week before last when
00:19:58 --> 00:19:59 we did the Dark Sky Festival there.
00:19:59 --> 00:20:02 Andrew Dunkley: Yeah, yeah he also
00:20:02 --> 00:20:05 asked about uh website. Yeah ah
00:20:05 --> 00:20:08 well I just did a quick cheque and top uh of
00:20:08 --> 00:20:11 the tree is NASA for up
00:20:11 --> 00:20:14 to date solar system information.
00:20:15 --> 00:20:17 Uh yeah, uh but the other ones that you could
00:20:17 --> 00:20:19 try uh the sky
00:20:19 --> 00:20:22 mylive.com apparently is
00:20:22 --> 00:20:25 very highly rated um says
00:20:25 --> 00:20:27 it offers comprehensive information about the
00:20:27 --> 00:20:29 most interesting celestial objects and sets
00:20:29 --> 00:20:32 tools designed to support the exploration et
00:20:32 --> 00:20:34 cetera. Uh the planets today
00:20:35 --> 00:20:38 uh is also there and there's a specific uh
00:20:38 --> 00:20:41 NASA page that you can look up
00:20:41 --> 00:20:44 called Eyes on the Solar System. Um,
00:20:44 --> 00:20:47 and it provides a 3D solar
00:20:47 --> 00:20:50 scape if you like. So there's a few
00:20:50 --> 00:20:53 ideas if you uh, want to um, chase them
00:20:53 --> 00:20:56 up, Martin. But um, there'd be plenty more
00:20:56 --> 00:20:58 out there. There's um, just to name a few
00:20:58 --> 00:21:00 more, Global Solar Atlas,
00:21:00 --> 00:21:03 um, the NOAA homepage,
00:21:03 --> 00:21:06 the Space Weather Prediction homepage, um,
00:21:06 --> 00:21:09 and Planet Labs just to name a few. So
00:21:10 --> 00:21:13 um, and they're constantly being updated as
00:21:13 --> 00:21:15 far as I'm aware, as things change or as
00:21:15 --> 00:21:18 new things come to light. So might be worth
00:21:18 --> 00:21:21 chasing all of those up because they do seem
00:21:21 --> 00:21:23 to be, um, highly credentialed. Fred Watson?
00:21:24 --> 00:21:27 Professor Fred Watson: Yeah, I was going to say I usually go
00:21:27 --> 00:21:29 to NASA when I want the latest figures on
00:21:30 --> 00:21:33 this sort of thing. M. So,
00:21:33 --> 00:21:35 uh, you've confirmed that and also given a
00:21:35 --> 00:21:37 few other options as well, which is good.
00:21:37 --> 00:21:38 Andrew Dunkley: Yep, plenty to look at. There's lots of great
00:21:38 --> 00:21:41 sites out there. Just don't go to the ones
00:21:41 --> 00:21:43 that start with um, words
00:21:43 --> 00:21:45 starting with F and e.
00:21:51 --> 00:21:53 Professor Fred Watson: I was thought you were going to say don't go
00:21:53 --> 00:21:55 to ones that start with space and have knots
00:21:55 --> 00:21:55 in the.
00:21:57 --> 00:21:59 Andrew Dunkley: That's, that's good advice too.
00:21:59 --> 00:21:59 Professor Fred Watson: Yeah.
00:22:00 --> 00:22:02 Andrew Dunkley: Okay, thank you, Martin.
00:22:02 --> 00:22:05 Our final question today comes from
00:22:05 --> 00:22:06 Finn.
00:22:06 --> 00:22:08 Speaker C: Hello, Andrew and Fred Watson. It's Finn from
00:22:08 --> 00:22:11 NAN in the Adelaide Hills in South
00:22:11 --> 00:22:14 Australia. And a happy May 4th to you as
00:22:14 --> 00:22:16 well. I was watching a 40 year old
00:22:16 --> 00:22:18 documentary the other day about a space
00:22:18 --> 00:22:21 station orbiting a planet. And this
00:22:21 --> 00:22:24 space station, um, if it was to orbit
00:22:24 --> 00:22:26 the Earth, I would like to know how that
00:22:26 --> 00:22:28 would affect the orbit of our
00:22:28 --> 00:22:31 moon and maybe the orbit of the Earth
00:22:31 --> 00:22:34 around the sun. This space station being 150
00:22:34 --> 00:22:36 kilometres diameter with a mass of about 10
00:22:36 --> 00:22:39 to the 15 tonne. Um, I'd
00:22:39 --> 00:22:42 like to know, and if for whatever reason this
00:22:42 --> 00:22:45 space station happened to destroy our planet,
00:22:46 --> 00:22:48 how would the rest of the planets in the
00:22:48 --> 00:22:50 solar system be affected by that
00:22:50 --> 00:22:53 destruction? One last question,
00:22:53 --> 00:22:56 um, to you both is, um, what was the first
00:22:56 --> 00:22:57 animal in space?
00:22:58 --> 00:22:59 Andrew Dunkley: It was a dog.
00:22:59 --> 00:23:02 Speaker C: Ah, ah, don't think it was that. It was
00:23:02 --> 00:23:04 actually the cow because it jumped over the
00:23:04 --> 00:23:06 moon. Thank you.
00:23:06 --> 00:23:07 Professor Fred Watson: Dear, oh dear.
00:23:07 --> 00:23:09 Andrew Dunkley: Finn. That was probably one of the worst dad
00:23:09 --> 00:23:12 jokes I've ever heard. So,
00:23:13 --> 00:23:15 but you know, most welcome on this show.
00:23:19 --> 00:23:20 Professor Fred Watson: Yeah, it was good. It wasn't, wasn't even
00:23:20 --> 00:23:21 adequate that one, was it?
00:23:21 --> 00:23:22 Andrew Dunkley: No, it wasn't.
00:23:22 --> 00:23:23 Professor Fred Watson: No, no.
00:23:23 --> 00:23:26 Andrew Dunkley: We strive for adequacy and we didn't even
00:23:26 --> 00:23:28 achieve that. Thank you, Finn.
00:23:28 --> 00:23:31 Uh, so the substance of his question was,
00:23:31 --> 00:23:34 uh, you got a space Station orbiting Earth
00:23:34 --> 00:23:36 at 150 kilometres in
00:23:37 --> 00:23:40 diameter or whatever. Uh what kind
00:23:40 --> 00:23:42 of effect could that have on the orbit of the
00:23:42 --> 00:23:45 Moon? And ye
00:23:46 --> 00:23:47 get to the next part of the question after
00:23:47 --> 00:23:49 that. Could it have, would that have any.
00:23:49 --> 00:23:50 That's pretty big.
00:23:52 --> 00:23:54 Professor Fred Watson: It's well the critical thing was the mass
00:23:54 --> 00:23:57 which um Fin actually
00:23:57 --> 00:24:00 mentioned as being 10 to
00:24:00 --> 00:24:03 the 15 tonnes I think is what he said
00:24:04 --> 00:24:07 uh which is 10 to the 18
00:24:07 --> 00:24:09 kilogrammes. Um and
00:24:10 --> 00:24:12 so the bottom line is that's not enough
00:24:14 --> 00:24:17 uh the Earth just. Yeah, nah, ah forget it.
00:24:17 --> 00:24:20 So the earth's uh six times 10 to the
00:24:20 --> 00:24:22 24 kilogrammes. So it's
00:24:23 --> 00:24:25 um, what is it? It's
00:24:26 --> 00:24:29 six uh orders of magnitude bigger in
00:24:29 --> 00:24:32 mass than uh this space station
00:24:33 --> 00:24:35 and so the other. So
00:24:37 --> 00:24:39 it's certainly not going to affect the orbit
00:24:39 --> 00:24:42 of the ah Earth. It might perturb
00:24:42 --> 00:24:44 the orbit of the Moon a bit.
00:24:45 --> 00:24:47 Uh one of the considerations will be how far
00:24:47 --> 00:24:50 away is it from the
00:24:50 --> 00:24:53 Earth? And uh, our last question
00:24:53 --> 00:24:56 actually pointed to an answer to that
00:24:56 --> 00:24:59 and that is that if it's 150
00:24:59 --> 00:25:02 kilometres in diameter it has to be a long
00:25:02 --> 00:25:04 way away or else it's within the Roche limit
00:25:06 --> 00:25:08 of the Earth uh and it would just break up
00:25:08 --> 00:25:10 straight away. So I'm not going to guess how
00:25:10 --> 00:25:12 far away it has to be but it'll be a long way
00:25:12 --> 00:25:15 the earth if it's 150 kilometres in diameter.
00:25:16 --> 00:25:18 Um so that again um, basically
00:25:18 --> 00:25:21 mitigates any effects it might have
00:25:21 --> 00:25:23 on the orbital dynamics of the Earth. It
00:25:23 --> 00:25:25 certainly wouldn't affect the Earth's orbit
00:25:25 --> 00:25:28 around the Sun. Might just tweak the
00:25:28 --> 00:25:30 Moon's orbit around the Earth a bit.
00:25:30 --> 00:25:33 Uh wouldn't cause the demolition of the
00:25:33 --> 00:25:36 Earth. The orbits of the other planets
00:25:36 --> 00:25:39 wouldn't even bother to, to take any
00:25:39 --> 00:25:42 notice of it. Uh they are too
00:25:42 --> 00:25:45 stable compared with uh, a
00:25:45 --> 00:25:48 thing of that mass and that far away from the
00:25:48 --> 00:25:50 Earth. So ah it's an interesting
00:25:50 --> 00:25:53 thought uh and one that I
00:25:53 --> 00:25:56 think um we can say yes you could have a
00:25:56 --> 00:25:58 space station 150 kilometres in diameter
00:25:58 --> 00:26:01 weighing 10 to the 15 tonnes uh and it
00:26:01 --> 00:26:04 probably would not affect the status quo
00:26:04 --> 00:26:05 terribly badly.
00:26:06 --> 00:26:08 Andrew Dunkley: Okay, there you go. Uh and I just did a quick
00:26:08 --> 00:26:11 cheque but um, there's not much information
00:26:11 --> 00:26:13 about how fast space stations have to be away
00:26:13 --> 00:26:16 to avoid the Roche limit. But a solid object
00:26:16 --> 00:26:19 such as a Rocky body
00:26:20 --> 00:26:22 with 150 kilometre diameter would have to be
00:26:22 --> 00:26:25 at least 141 kilometres
00:26:25 --> 00:26:28 away from Earth. Um probably better off being
00:26:28 --> 00:26:30 over 200 kilometres away.
00:26:30 --> 00:26:32 Professor Fred Watson: Yes that's the sort of distance I had in
00:26:32 --> 00:26:35 mind. Something like that. Three times as
00:26:35 --> 00:26:37 far away as the, the geostationary
00:26:37 --> 00:26:38 satellites. Huh.
00:26:38 --> 00:26:39 Andrew Dunkley: Are. There you are now.
00:26:39 --> 00:26:42 He had a second question as to what would
00:26:42 --> 00:26:44 happen to the other planets if Earth was
00:26:44 --> 00:26:46 destroyed, no longer existed. I think we've
00:26:46 --> 00:26:48 been down this road before and I can't
00:26:48 --> 00:26:49 remember the answer.
00:26:50 --> 00:26:52 Professor Fred Watson: Yeah, so, um, the other planets
00:26:52 --> 00:26:55 would more or less stay in the present
00:26:55 --> 00:26:58 orbits. Those orbits would be
00:26:58 --> 00:27:00 perturbed, uh, differently from what they are
00:27:00 --> 00:27:03 now. So perturbations are the gravitational
00:27:03 --> 00:27:05 effects of other bodies in the solar system.
00:27:06 --> 00:27:09 Uh, when you look at the way
00:27:09 --> 00:27:11 things are in orbit, you start off with a two
00:27:11 --> 00:27:14 body problem with the sun and your object in
00:27:14 --> 00:27:16 orbit. But then you modify it by
00:27:17 --> 00:27:19 taking into account the gravitational
00:27:19 --> 00:27:20 attraction of other bodies and it becomes a
00:27:20 --> 00:27:22 three body problem and then four body problem
00:27:22 --> 00:27:25 and all the rest of it. Now,
00:27:25 --> 00:27:27 that three body problem would change if the
00:27:27 --> 00:27:30 Earth wasn't there. Um, or the N body
00:27:30 --> 00:27:32 problem, I suppose it would be a solar system
00:27:32 --> 00:27:34 with seven planets rather than eight. Uh,
00:27:35 --> 00:27:37 that would change the dynamics of the planets
00:27:37 --> 00:27:40 a little bit, but they would basically
00:27:40 --> 00:27:42 remain in their present orbits, uh, with
00:27:42 --> 00:27:45 just changes to the orbit rather than the
00:27:45 --> 00:27:46 orbits being destroyed.
00:27:46 --> 00:27:48 Andrew Dunkley: So, uh, in other words, if Earth disappeared,
00:27:48 --> 00:27:49 no great loss.
00:27:50 --> 00:27:53 Professor Fred Watson: No, not really. I mean, uh, you know, Douglas
00:27:53 --> 00:27:55 Adams had it in one. Mostly harmless. Mostly
00:27:55 --> 00:27:57 harmless, that's right.
00:27:57 --> 00:27:58 Andrew Dunkley: Thanks to the white mice.
00:27:59 --> 00:28:00 Professor Fred Watson: Yes, that's right.
00:28:01 --> 00:28:03 Andrew Dunkley: I wonder how all the other mice felt about
00:28:03 --> 00:28:06 that. You know, it was
00:28:06 --> 00:28:08 musculus. Racism. That's what it was.
00:28:08 --> 00:28:11 Professor Fred Watson: It is, yes. Mass racism. Exactly. So,
00:28:12 --> 00:28:14 yeah, thanks.
00:28:14 --> 00:28:16 Andrew Dunkley: Uh, Finn, great question. We always love
00:28:16 --> 00:28:18 these what ifs. So, um, if you'd like to keep
00:28:18 --> 00:28:20 sending in questions like that, or if you've
00:28:20 --> 00:28:22 got something deadly serious to discuss with
00:28:22 --> 00:28:25 us, like, uh, I don't know, exploding
00:28:25 --> 00:28:27 rockets and whatever else, uh, you can send
00:28:27 --> 00:28:30 them in to us. Uh, just go to spacenuts
00:28:30 --> 00:28:33 IO or spacenutspodcast.com,
00:28:33 --> 00:28:35 click on the Ask me anything button.
00:28:36 --> 00:28:38 You won't be asking me, you'll be asking him.
00:28:39 --> 00:28:41 But, uh, I'll read it out or you can send us
00:28:41 --> 00:28:43 audio question. As long as you've got a
00:28:43 --> 00:28:45 device with a microphone, you're all set. Uh,
00:28:45 --> 00:28:46 and while you're there, have a look around.
00:28:47 --> 00:28:48 Uh, that brings us to the end. Fred Watson,
00:28:48 --> 00:28:49 thank you very much.
00:28:50 --> 00:28:52 Professor Fred Watson: Great pleasure, Andrew. Always good to chew
00:28:52 --> 00:28:54 the fat. And, uh, I, uh, hope we'll do it
00:28:54 --> 00:28:54 again soon.
00:28:54 --> 00:28:55 Andrew Dunkley: We will.
00:28:55 --> 00:28:56 That's Professor Fred Watson Watson,
00:28:56 --> 00:28:58 astronomer at large, part of the team here at
00:28:58 --> 00:29:00 Space Nuts and thanks to Huw in the studio.
00:29:01 --> 00:29:02 Uh, who couldn't be with us today. He was
00:29:02 --> 00:29:04 seeing his dietitian after he reached 10 to
00:29:04 --> 00:29:05 the 15 tonnes.
00:29:08 --> 00:29:10 I'm surprised he survived. And from me,
00:29:10 --> 00:29:12 Andrew Dunkley. Thanks for your company.
00:29:12 --> 00:29:14 We'll be back again soon with another episode
00:29:14 --> 00:29:16 of Space Nuts. See you then.
00:29:16 --> 00:29:17 Professor Fred Watson: Bye. Bye.
00:29:18 --> 00:29:20 Andrew Dunkley: You've been listening to the Space Nuts
00:29:20 --> 00:29:23 podcast, available at
00:29:23 --> 00:29:25 Apple Podcasts, Spotify,
00:29:25 --> 00:29:28 iHeartRadio or your favourite podcast
00:29:28 --> 00:29:30 player. You can also stream on
00:29:30 --> 00:29:33 demand@bytes.com. this has been another
00:29:33 --> 00:29:35 quality podcast production from
00:29:35 --> 00:29:36 bytes.com.