To check out our special NordVPN deal with big savings, Click Here
White Dwarfs, Black Holes, and Cosmic Oddities In this enlightening Q&A edition of Space Nuts, hosts Andrew Dunkley and Professor Fred Watson tackle a plethora of intriguing audience questions that span the cosmos. From the fascinating processes of white dwarf stars to the mysteries of black holes and the peculiarities of space, this episode is a treasure trove of astronomical insights.
Episode Highlights:
- Understanding White Dwarf Crystallisation: Mark from Bloomington, Indiana, poses a thought-provoking question about the crystallisation process of white dwarfs and how it affects their cooling. Andrew and Fred Watson delve into the lifecycle of these stars, exploring the formation of diamond cores and the implications for the universe's timeline.
- Black Holes and Gravitational Forces: Steve from Tin Can Bay wonders about the effects of falling into different sized black holes. The hosts discuss the concept of spaghettification and how the gravitational gradient varies between smaller and supermassive black holes, shedding light on the physics of these enigmatic entities.
- Gravity in Orbit: Wayne's question leads to a discussion on how astronauts experience gravity while in orbit and how far they must travel to feel its absence. Andrew and Fred Watson explain the nuances of gravitational pull and the complexities of interplanetary travel, highlighting the continuous influence of celestial bodies.
- Oddities of the Cosmos: Casey from Colorado asks about the weirdest phenomena in space, prompting a lively discussion on everything from dark matter and dark energy to the peculiar shapes of celestial objects. The hosts share their favourite cosmic curiosities, including the coincidence of the sun and moon appearing the same size in the sky and the bizarre nature of neutron stars.
For more Space Nuts, including our continuously updating newsfeed and to listen to all our episodes, visit our website. Follow us on social media at SpaceNutsPod on Facebook, Instagram, and more. We love engaging with our community, so be sure to drop us a message or comment on your favourite platform.
If you’d like to help support Space Nuts and join our growing family of insiders for commercial-free episodes and more, visit spacenutspodcast.com/about.
Stay curious, keep looking up, and join us next time for more stellar insights and cosmic wonders. Until then, clear skies and happy stargazing.
Become a supporter of this podcast: https://www.spreaker.com/podcast/space-nuts-astronomy-insights-cosmic-discoveries--2631155/support.
00:00:00 --> 00:00:02 Andrew Dunkley: Hi there. Thanks for joining us on another
00:00:02 --> 00:00:04 episode of Space Nuts. This is a Q and A
00:00:04 --> 00:00:07 edition. This is where we answer audience
00:00:07 --> 00:00:10 questions. Well, we read them out or we
00:00:10 --> 00:00:12 listen to them and we nod
00:00:13 --> 00:00:15 and then we go home. Uh, today we're
00:00:15 --> 00:00:18 going to be discussing white dwarf stars. An
00:00:18 --> 00:00:20 interesting question, a double barreled
00:00:20 --> 00:00:23 question in fact. Um, we've got
00:00:23 --> 00:00:26 one about uh, the different size of black
00:00:26 --> 00:00:28 holes. Gosh, a question about black holes.
00:00:28 --> 00:00:31 How odd. Uh, the effect of being in orbit
00:00:32 --> 00:00:34 come up and Casey wants to know about
00:00:34 --> 00:00:37 some of the oddities that exist in the
00:00:37 --> 00:00:40 cosmos. We'll cover all of that in this
00:00:40 --> 00:00:42 edition of space nuts. 15
00:00:42 --> 00:00:45 seconds. Guidance is internal. 10,
00:00:45 --> 00:00:48 9, ignition sequence start.
00:00:48 --> 00:00:49 Professor Fred Watson: Space nuts.
00:00:49 --> 00:00:52 Andrew Dunkley: 5, 4, 3, 2. 1, 2, 3, 4,
00:00:52 --> 00:00:55 5, 5, 4, 3, 2, 1. Space
00:00:55 --> 00:00:57 nuts. Astronauts report it feels good.
00:00:58 --> 00:01:01 And Fred Watson brought with him today his
00:01:01 --> 00:01:03 brain the size of a planet to answer all your
00:01:03 --> 00:01:04 questions. Professor Fred Watson, what's an
00:01:04 --> 00:01:06 astronomer at large? Hello Fred Watson.
00:01:06 --> 00:01:08 Professor Fred Watson: Hello Andrew. Fancy seeing you here.
00:01:09 --> 00:01:10 Andrew Dunkley: It's unusual, isn't it, really?
00:01:13 --> 00:01:15 We've got a fair bit to get through, so we
00:01:15 --> 00:01:18 might just get straight into it, uh,
00:01:18 --> 00:01:20 as they say in Britain, we'll muck in.
00:01:21 --> 00:01:24 Professor Fred Watson: Um, I think it's, you'll find it's muckin
00:01:24 --> 00:01:25 nookin mukin.
00:01:25 --> 00:01:27 Andrew Dunkley: I've got to get the accent right.
00:01:27 --> 00:01:27 Professor Fred Watson: Yes, of course.
00:01:29 --> 00:01:32 Andrew Dunkley: All right, uh, our first question comes from
00:01:32 --> 00:01:34 Bloomington, Indiana. Two questions, if I
00:01:34 --> 00:01:37 may, about white dwarf stars. After a very
00:01:37 --> 00:01:40 long period of initial cooling, white
00:01:40 --> 00:01:42 dwarf stars undergo crystallisation before
00:01:42 --> 00:01:45 eventually transforming into theoretical
00:01:45 --> 00:01:48 black dwarf objects. So the
00:01:48 --> 00:01:50 questions are, uh, what is the process of
00:01:50 --> 00:01:53 crystallisation and how might crystallisation
00:01:53 --> 00:01:56 slow the further cooling of a white dwarf for
00:01:56 --> 00:01:58 such an incredibly long time? Thank you very
00:01:58 --> 00:02:00 much for your terrific podcast, Keep Smiling
00:02:00 --> 00:02:03 in the Land down under. That comes from Mark.
00:02:03 --> 00:02:06 Thank you, Mark. Lovely to hear from you. We
00:02:06 --> 00:02:08 don't talk all that often about white dwarfs,
00:02:08 --> 00:02:11 although we have had them pop up a couple of
00:02:11 --> 00:02:14 times lately. But um, yeah, you might want to
00:02:14 --> 00:02:16 tackle that uh, process of crystallisation
00:02:16 --> 00:02:18 first. What is that?
00:02:19 --> 00:02:22 Professor Fred Watson: Uh, so, um, you need to sort of think about
00:02:22 --> 00:02:24 what a white dwarf is before you get to the
00:02:24 --> 00:02:25 crystallisation.
00:02:25 --> 00:02:28 Andrew Dunkley: I suppose so, yeah, yeah. Is that what our,
00:02:28 --> 00:02:29 uh, sun's going to turn into?
00:02:29 --> 00:02:32 Professor Fred Watson: Yeah, yeah it is. So, uh, a couple of weeks
00:02:32 --> 00:02:35 time, I think, uh, it was it
00:02:35 --> 00:02:37 uh, after tomorrow, wasn't it? I can't
00:02:37 --> 00:02:39 remember. Yeah, anyway, um, it's or the, the
00:02:39 --> 00:02:41 Andrew Dunkley: billionth of a year after tomorrow.
00:02:43 --> 00:02:46 Professor Fred Watson: Yes, it's about, uh, so
00:02:46 --> 00:02:49 it will be in the region of 5 billion
00:02:49 --> 00:02:49 years.
00:02:50 --> 00:02:50 Andrew Dunkley: Oh, that's okay.
00:02:50 --> 00:02:53 Professor Fred Watson: Then have to put up with that. So
00:02:53 --> 00:02:56 uh, as well, let's take this and as an
00:02:56 --> 00:02:58 example, so the um, the outer.
00:02:58 --> 00:03:00 So what, what basically happens at the
00:03:00 --> 00:03:02 moment? We've got this reaction taking place
00:03:02 --> 00:03:05 that converts hydrogen into helium
00:03:06 --> 00:03:08 and produces a few other things as well.
00:03:08 --> 00:03:11 There are other reactions going on, uh, many
00:03:11 --> 00:03:14 of which produce carbon. Uh, and so
00:03:14 --> 00:03:17 carbon sort of builds up in the core
00:03:17 --> 00:03:20 of the sun over
00:03:20 --> 00:03:23 time and in particular as, as it
00:03:23 --> 00:03:25 gets nearer the end of its life it becomes
00:03:25 --> 00:03:28 quite carbon rich, uh, the
00:03:28 --> 00:03:31 nuc. So um,
00:03:32 --> 00:03:35 when it sheds its outer
00:03:35 --> 00:03:38 atmosphere and turns into what we call a
00:03:38 --> 00:03:40 planetary nebula. Nothing to do with planets,
00:03:40 --> 00:03:41 it's just that the early astronomers thought
00:03:41 --> 00:03:43 they looked like planets, but they're
00:03:43 --> 00:03:45 actually clouds of gas. Yeah, um, William
00:03:45 --> 00:03:47 Herschel, who called them planetary nebulae,
00:03:47 --> 00:03:50 he called a lot of things their names that we
00:03:50 --> 00:03:52 still use. Very eminent astronomer.
00:03:52 --> 00:03:55 Anyway, you get a planetary nebula,
00:03:55 --> 00:03:58 uh, but the, the core of the
00:03:58 --> 00:04:01 star that's left
00:04:02 --> 00:04:04 uh, behind basically
00:04:04 --> 00:04:07 collapses under its own gravity because it
00:04:07 --> 00:04:09 doesn't have the radiation any longer to
00:04:10 --> 00:04:13 support a swollen star. If
00:04:13 --> 00:04:15 I can put it that way. Radiation's gone.
00:04:16 --> 00:04:19 So uh, it's still. But it's incredibly hot,
00:04:19 --> 00:04:22 which is why it's a white dwarf. It's because
00:04:23 --> 00:04:26 the radiation pushes it into a very
00:04:26 --> 00:04:29 extreme white part of the spectrum. A bit
00:04:29 --> 00:04:31 like uh, a lot of the headlights on cars
00:04:31 --> 00:04:34 these days with LED, ultra white
00:04:34 --> 00:04:37 LEDs, it's that sort of thing. Um, but for
00:04:37 --> 00:04:39 different processes it's very hot. That's why
00:04:39 --> 00:04:42 it radiates the whiteness. Uh, but it
00:04:42 --> 00:04:44 basically uh, is an object with
00:04:45 --> 00:04:48 uh, it's in a state of what's
00:04:48 --> 00:04:51 called electron degeneracy. And that means
00:04:52 --> 00:04:55 that the electrons
00:04:55 --> 00:04:58 are uh, the only thing stopping it collapsing
00:04:58 --> 00:05:00 into something more dense
00:05:01 --> 00:05:04 like ah, a black hole. So it's this electron
00:05:04 --> 00:05:06 pressure that uh, sort of stops a
00:05:06 --> 00:05:09 further collapse. Uh, and
00:05:09 --> 00:05:12 essentially um, you've got.
00:05:14 --> 00:05:16 Matter does very, very funny things under
00:05:16 --> 00:05:19 those circumstances because it's under
00:05:19 --> 00:05:22 extreme compression. Uh, and
00:05:22 --> 00:05:24 so you've got basically
00:05:26 --> 00:05:28 a carbon oxygen rich
00:05:28 --> 00:05:31 carbon core which uh, in the
00:05:31 --> 00:05:33 initial stages, uh, as Mark
00:05:34 --> 00:05:37 says, uh, um, after a very
00:05:37 --> 00:05:38 long period of initial cooling, that's what
00:05:38 --> 00:05:41 he says in those initial stages, uh,
00:05:41 --> 00:05:44 it's liquid, It's a liquid core, a liquid of
00:05:44 --> 00:05:47 carbon and oxygen. Uh, and
00:05:47 --> 00:05:50 it's very hard for us to imagine
00:05:50 --> 00:05:53 that now as that cools it,
00:05:53 --> 00:05:56 uh, it's when the crystallisation takes
00:05:56 --> 00:05:59 place, it becomes a lattice of rather than
00:05:59 --> 00:06:01 a slushy liquid of these Atoms,
00:06:02 --> 00:06:05 they form a lattice structure which we call a
00:06:05 --> 00:06:07 crystal. Uh, and
00:06:08 --> 00:06:11 that uh. So Mark asks
00:06:11 --> 00:06:13 what's the process of crystallisation? It's
00:06:13 --> 00:06:15 the cooling of the, of the liquid core
00:06:15 --> 00:06:18 further. Uh, so uh, under the extreme
00:06:18 --> 00:06:20 pressure you get basically diamond
00:06:20 --> 00:06:23 forming, that's what it is. Um,
00:06:23 --> 00:06:26 and so that crystallisation, it means that
00:06:26 --> 00:06:28 the core is diamond related.
00:06:29 --> 00:06:31 Um so uh,
00:06:32 --> 00:06:34 that's the sort of end product.
00:06:35 --> 00:06:37 Um, so
00:06:39 --> 00:06:41 then that process of
00:06:42 --> 00:06:44 diamond formation actually releases
00:06:44 --> 00:06:47 heat, what we call latent heat. It releases
00:06:47 --> 00:06:50 heat and so it slows down the
00:06:50 --> 00:06:53 star's cooling. Uh, and apparently it slows
00:06:53 --> 00:06:56 it down by roughly a billion years.
00:06:57 --> 00:07:00 Uh, and so the
00:07:00 --> 00:07:02 suggestion, uh, there's a comment here that
00:07:02 --> 00:07:05 um, I'm looking at that says Gaia data,
00:07:05 --> 00:07:07 that's the measurement of the positions of
00:07:07 --> 00:07:10 billions of stars and their colours.
00:07:11 --> 00:07:13 Recent uh, Gaia data suggests this is a
00:07:13 --> 00:07:16 common 10 million year long high density
00:07:16 --> 00:07:18 phase. Uh, but when it,
00:07:20 --> 00:07:23 when it, when um, when you've, when
00:07:23 --> 00:07:25 you've basically not quite sure why, there's
00:07:25 --> 00:07:28 a conflict of numbers there which are
00:07:28 --> 00:07:30 struggling to understand. But if you've got
00:07:30 --> 00:07:33 the star cooling delayed by a
00:07:33 --> 00:07:34 billion years and then
00:07:36 --> 00:07:38 the cooling phase keeps on going,
00:07:38 --> 00:07:41 uh, you've got then many tens of billions of
00:07:41 --> 00:07:44 years before it becomes a cold and dead
00:07:44 --> 00:07:46 object, uh, which we call a black dwarf.
00:07:46 --> 00:07:48 Uh, I don't think there are any black dwarfs
00:07:48 --> 00:07:50 yet because the universe isn't old enough for
00:07:50 --> 00:07:53 them to, them to be, to have been created.
00:07:53 --> 00:07:56 Andrew Dunkley: So they're theoretical. But they um,
00:07:56 --> 00:07:58 might suppose in terms of
00:07:59 --> 00:08:00 theoretical, they're probable.
00:08:01 --> 00:08:03 Professor Fred Watson: Yes, that's right. That's about right.
00:08:04 --> 00:08:05 Andrew Dunkley: Okay.
00:08:05 --> 00:08:07 Professor Fred Watson: The diamond stars, I mean it's a nice
00:08:07 --> 00:08:07 concept, isn't it?
00:08:07 --> 00:08:10 Andrew Dunkley: Yeah. Gee, it's such a. Time frames
00:08:10 --> 00:08:13 that you just can't, yeah.
00:08:13 --> 00:08:16 Contemplate. It just makes us seem so tiny
00:08:16 --> 00:08:18 and small and insignificant, doesn't it?
00:08:19 --> 00:08:21 Professor Fred Watson: Uh, yes. Although we're important to each
00:08:21 --> 00:08:22 other.
00:08:22 --> 00:08:25 Andrew Dunkley: Yeah, that's, that's true. Um, I, I was
00:08:25 --> 00:08:26 just doing a bit of research while you were
00:08:26 --> 00:08:29 talking. Apparently they think 97%
00:08:29 --> 00:08:31 of stars in the Milky Way will become white
00:08:31 --> 00:08:32 dwarfs.
00:08:32 --> 00:08:35 Professor Fred Watson: Yeah, that's right. They're, they're, you
00:08:35 --> 00:08:38 know, they're the ones that go supernova are
00:08:38 --> 00:08:38 the rarities.
00:08:40 --> 00:08:42 Andrew Dunkley: That's good though. I mean imagine if 97
00:08:42 --> 00:08:44 of the stars in the Milky Way became black
00:08:44 --> 00:08:46 holes. We'd all be in trouble.
00:08:46 --> 00:08:47 Professor Fred Watson: Yeah.
00:08:48 --> 00:08:49 Andrew Dunkley: Could be messy.
00:08:49 --> 00:08:52 Professor Fred Watson: Uh, that, that's right. Yes we
00:08:52 --> 00:08:55 would, it would be a much more
00:08:55 --> 00:08:57 um, inhospitable universe.
00:08:57 --> 00:09:00 Andrew Dunkley: Indeed. Thank you, Mark.
00:09:00 --> 00:09:02 Hopefully we adequately answered Your
00:09:02 --> 00:09:02 question.
00:09:02 --> 00:09:05 Great to hear from you. Uh, we've got an
00:09:05 --> 00:09:06 audio question now. This one comes from
00:09:06 --> 00:09:07 Steve.
00:09:07 --> 00:09:10 Speaker C: Hi guys. Love your podcast. Keeps
00:09:10 --> 00:09:13 me uh, awake a little later every
00:09:13 --> 00:09:14 evening listening.
00:09:16 --> 00:09:18 Steve here from Tin Can Bay
00:09:18 --> 00:09:21 in Queensland. Very dark sky
00:09:21 --> 00:09:24 place actually. And my question is to
00:09:24 --> 00:09:27 do with different sized black holes
00:09:27 --> 00:09:29 and gravitational gradient.
00:09:30 --> 00:09:32 Not that I know much about this. I was
00:09:32 --> 00:09:35 wondering, um, if you fell into a
00:09:35 --> 00:09:38 smaller black hole, believe this
00:09:38 --> 00:09:41 specification effect where the
00:09:41 --> 00:09:43 gravity at one end of your body to the other
00:09:43 --> 00:09:46 would tear uh, you apart, that if you
00:09:46 --> 00:09:47 free fell into a
00:09:49 --> 00:09:51 super large black hole,
00:09:52 --> 00:09:55 wouldn't the gravitational gradient be
00:09:56 --> 00:09:58 more even out across the plane and
00:09:59 --> 00:10:01 you uh, would just free fall into it?
00:10:03 --> 00:10:06 Can explain that and make
00:10:06 --> 00:10:06 more sense of it.
00:10:08 --> 00:10:10 Andrew Dunkley: Thank you, Steve. Uh, Tin Can Bay. What a
00:10:10 --> 00:10:12 beautifully named place. I love it.
00:10:13 --> 00:10:15 Professor Fred Watson: Have you ever been, Andrew?
00:10:15 --> 00:10:16 Andrew Dunkley: I haven't been there, no.
00:10:16 --> 00:10:17 Professor Fred Watson: No, I haven't either.
00:10:18 --> 00:10:20 Andrew Dunkley: Yeah, sounds like it's a great place to
00:10:20 --> 00:10:22 visit, especially at night if it's a dark sky
00:10:22 --> 00:10:23 area. Fantastic.
00:10:23 --> 00:10:24 Professor Fred Watson: Yep. Cheque it out.
00:10:24 --> 00:10:27 Andrew Dunkley: Um, so we're talking about different sized
00:10:27 --> 00:10:30 black holes and if you fell into them, well,
00:10:30 --> 00:10:32 we all know what would probably happen. But
00:10:32 --> 00:10:35 uh, what if it's super large? Uh, is
00:10:35 --> 00:10:37 its gravitational gradient spread evenly
00:10:37 --> 00:10:39 and does that mean you could fall into it
00:10:39 --> 00:10:40 without too much trouble?
00:10:42 --> 00:10:45 Professor Fred Watson: I think, um, so if you think about the um,
00:10:45 --> 00:10:47 the gravitational, well the shape of this,
00:10:48 --> 00:10:51 this sort of vortex that is the black
00:10:51 --> 00:10:54 hole in gravity. Um, yes,
00:10:54 --> 00:10:57 for a bigger black hole, ah, black hole, uh,
00:10:57 --> 00:11:00 it will be less steep. It will
00:11:00 --> 00:11:03 basically extend over a much wider area than
00:11:03 --> 00:11:05 for a small black hole and will start
00:11:05 --> 00:11:08 off less steep because it's, it's a gentler
00:11:08 --> 00:11:11 slope, um, which means, and
00:11:11 --> 00:11:13 what that's telling you is the event horizon
00:11:13 --> 00:11:16 is bigger, uh, for a larger
00:11:16 --> 00:11:19 black hole, a larger mass black hole, but the
00:11:19 --> 00:11:22 end product is pretty well all always
00:11:22 --> 00:11:24 the same. Uh, maybe your
00:11:24 --> 00:11:27 spaghettification will be a bit gentler, but
00:11:27 --> 00:11:29 you're always going to end up in a very, very
00:11:29 --> 00:11:32 steep gravity gradient. Um, and
00:11:32 --> 00:11:35 yes, I think, um,
00:11:35 --> 00:11:37 uh, you know, Steve's question, Steve's
00:11:37 --> 00:11:38 thinking I think is right, that
00:11:40 --> 00:11:43 the way that gradient changes is what
00:11:43 --> 00:11:45 uh, tells you how quickly you're going to be
00:11:45 --> 00:11:48 spaghettified. Um, and it changes
00:11:48 --> 00:11:51 more slowly for a larger mass black hole than
00:11:51 --> 00:11:54 for a smaller black hole. But uh,
00:11:54 --> 00:11:56 you're still going to wind up in deep trou,
00:11:56 --> 00:11:58 um, you're still going to get spaghettified
00:11:59 --> 00:11:59 in the end.
00:12:00 --> 00:12:02 Andrew Dunkley: Yeah, I suppose depending on the size and
00:12:02 --> 00:12:04 gravity effect of the black hole, it could be
00:12:04 --> 00:12:07 spaghettified or linguinified
00:12:07 --> 00:12:10 you know, it could, it could be variables
00:12:10 --> 00:12:10 like that.
00:12:11 --> 00:12:14 Professor Fred Watson: It could be. Yes, that's right. Yes. Yeah.
00:12:14 --> 00:12:15 Andrew Dunkley: Well, I haven't thought to fly pastified.
00:12:16 --> 00:12:18 That would be. That would be really
00:12:18 --> 00:12:18 different.
00:12:19 --> 00:12:20 Professor Fred Watson: Yeah.
00:12:20 --> 00:12:22 Andrew Dunkley: Uh, very unusual. But, um, I think in the
00:12:22 --> 00:12:24 movie Interstellar, they broke the laws of
00:12:24 --> 00:12:26 physics when they actually did successfully
00:12:26 --> 00:12:29 go through a black hole at one point in that
00:12:29 --> 00:12:32 film. Um, I think they did. I think they
00:12:32 --> 00:12:34 described it as a. It was a supermassive
00:12:34 --> 00:12:36 black hole, but it was very, very well
00:12:36 --> 00:12:39 tempered, something to that effect.
00:12:40 --> 00:12:43 Um, but yes, that, that, um. Because what
00:12:43 --> 00:12:45 they were looking for was only available to
00:12:45 --> 00:12:48 them, uh, in terms of research on the
00:12:48 --> 00:12:51 inside of a black hole. And so they had to go
00:12:51 --> 00:12:53 in there and find what they needed to save
00:12:53 --> 00:12:53 the world.
00:12:54 --> 00:12:55 Professor Fred Watson: Yeah, Y.
00:12:57 --> 00:12:58 Yes, that's right.
00:12:59 --> 00:13:01 Andrew Dunkley: Great film though. One of my favourites. Uh,
00:13:01 --> 00:13:04 thank you, Steve. Hopefully we answered, uh,
00:13:04 --> 00:13:07 your question today on Space Nuts. Uh,
00:13:07 --> 00:13:10 and you're listening to a Q A edition with
00:13:10 --> 00:13:12 Andrew Dunkley and Professor Fred Watson
00:13:12 --> 00:13:12 Watson.
00:13:16 --> 00:13:18 Speaker C: M. Space Nuts.
00:13:18 --> 00:13:20 Andrew Dunkley: Okay, uh, next question, Fred Watson. Over
00:13:20 --> 00:13:22 the years, Fred Watson has explained how
00:13:22 --> 00:13:25 astronauts orbiting the Earth are affected by
00:13:25 --> 00:13:28 gravity about the same as us because
00:13:28 --> 00:13:30 they are in effect continually falling. When
00:13:30 --> 00:13:33 they leave orbit and head into space, how far
00:13:33 --> 00:13:36 do they need to travel before they no longer
00:13:36 --> 00:13:38 feel the effects of gravity? Also,
00:13:39 --> 00:13:41 uh, when they orbit the moon, is it the same
00:13:41 --> 00:13:43 as orbiting the Earth? Uh, that one comes
00:13:43 --> 00:13:45 from Wayne. Hi, Wayne. Thanks for the
00:13:45 --> 00:13:45 question.
00:13:48 --> 00:13:51 Professor Fred Watson: Yes. So how far do you need to
00:13:51 --> 00:13:51 go?
00:13:52 --> 00:13:53 Andrew Dunkley: I had a question, but it dropped out of my
00:13:53 --> 00:13:56 head. But, um, uh, I suppose that the first
00:13:56 --> 00:13:58 point we look at, if you're orbiting Earth,
00:13:58 --> 00:14:00 you're continually falling, but
00:14:00 --> 00:14:03 you're still, uh, feeling weightlessness,
00:14:03 --> 00:14:03 aren't you?
00:14:04 --> 00:14:07 Professor Fred Watson: Yes. So that's how it works. You're
00:14:07 --> 00:14:09 being pulled towards the centre of the Earth
00:14:09 --> 00:14:12 by gravity. Uh, and you're feeling much the
00:14:12 --> 00:14:14 same gravity as we do on the surface. Uh, but
00:14:14 --> 00:14:16 what's stopping you from falling is your
00:14:16 --> 00:14:19 forward motion. You're always, um,
00:14:19 --> 00:14:22 moving, uh, in an orbit that means
00:14:22 --> 00:14:25 that you never actually reach the centre of
00:14:25 --> 00:14:27 the Earth. Uh, which is just as well because
00:14:27 --> 00:14:30 it's not a nice place. No, um, not really,
00:14:30 --> 00:14:33 but. Okay. So then you, uh, you fire your
00:14:34 --> 00:14:36 rockets, you do translunar injection or
00:14:36 --> 00:14:39 whatever that is. Uh,
00:14:39 --> 00:14:41 wherever you're going, if you're going to the
00:14:41 --> 00:14:42 moon, it's a translunar injection, that's
00:14:42 --> 00:14:45 what they call it, which puts you.
00:14:45 --> 00:14:48 Takes you from the orbit that you're in, a
00:14:48 --> 00:14:50 circular orbit around the Earth and puts you
00:14:50 --> 00:14:53 into a different orbit which,
00:14:53 --> 00:14:56 uh, will carry you out towards the moon.
00:14:56 --> 00:14:59 Uh, and if you don't do anything, uh,
00:14:59 --> 00:15:01 as happened with Artemis 2, there were a
00:15:01 --> 00:15:03 couple of minor course corrections, but
00:15:03 --> 00:15:04 basically that will bring you back to Earth
00:15:05 --> 00:15:07 because you're still in an orbit,
00:15:08 --> 00:15:10 even though it's a very long thin one. It was
00:15:10 --> 00:15:13 a figure of 8:1 in the case of Artemis 2. But
00:15:13 --> 00:15:14 you're still in orbit, you're still being
00:15:14 --> 00:15:17 pulled towards the Earth. Uh, the Earth's
00:15:17 --> 00:15:19 gravity is
00:15:19 --> 00:15:22 reducing, uh, as you go further out,
00:15:24 --> 00:15:27 uh, um, but you're still
00:15:27 --> 00:15:29 feeling it. And okay, uh, if
00:15:29 --> 00:15:31 you go out, uh, to Saturn,
00:15:33 --> 00:15:35 um, you're still feeling the Earth's gravity.
00:15:35 --> 00:15:36 Um,
00:15:39 --> 00:15:41 there comes a time, uh, which is when
00:15:41 --> 00:15:44 you expand your voyage beyond the
00:15:44 --> 00:15:46 Earth moon system. There comes a time when
00:15:46 --> 00:15:49 you're feeling the sun's gravity more so
00:15:50 --> 00:15:51 of technically in orbit around the sun. And
00:15:51 --> 00:15:54 that's what happens with interplanetary
00:15:54 --> 00:15:56 probes. You go to Saturn,
00:15:58 --> 00:16:01 you're in an orbit, but you're still being
00:16:01 --> 00:16:03 pulled back towards the sun. And if you don't
00:16:03 --> 00:16:06 do anything when you get to Saturn, like fire
00:16:06 --> 00:16:08 your braking rockets to slow you down, to put
00:16:08 --> 00:16:10 you in orbit around Saturn, if you don't do
00:16:10 --> 00:16:12 anything, you'll wind up going back to the
00:16:12 --> 00:16:15 sun. You'll end up coming back.
00:16:15 --> 00:16:17 Andrew Dunkley: Is that what's happening with comets and
00:16:17 --> 00:16:18 asteroids?
00:16:18 --> 00:16:21 Professor Fred Watson: Yeah, yeah. They're just feeling the pull of,
00:16:21 --> 00:16:24 so, um, comets in particular. Out there in
00:16:24 --> 00:16:25 the Oort cloud, they get a little bit of a
00:16:25 --> 00:16:27 nudge. That means that um,
00:16:28 --> 00:16:31 their velocity is not enough to keep them
00:16:31 --> 00:16:34 from falling in towards the sun. Uh,
00:16:34 --> 00:16:36 and so they do. And it takes them a long time
00:16:36 --> 00:16:39 to get in towards the sun. Hundreds of
00:16:39 --> 00:16:41 thousands of years, but they still do it.
00:16:41 --> 00:16:42 They're still in orbit.
00:16:43 --> 00:16:46 Andrew Dunkley: Okay, so how, how far would
00:16:46 --> 00:16:48 you have to go outside the solar system
00:16:49 --> 00:16:51 to not feel that effect?
00:16:53 --> 00:16:55 Or you're always going to feel something
00:16:55 --> 00:16:55 somewhere.
00:16:55 --> 00:16:58 Professor Fred Watson: Yeah, gravity's not something that
00:16:59 --> 00:17:01 disappears. It actually falls
00:17:01 --> 00:17:04 away and uh, effectively becomes zero at
00:17:04 --> 00:17:07 very big distances. But it's still there, as
00:17:07 --> 00:17:10 witnessed by the oak clouds a light year away
00:17:10 --> 00:17:12 or something like that. Um, you know,
00:17:13 --> 00:17:15 um, the,
00:17:16 --> 00:17:19 what eventually happens in interstellar space
00:17:19 --> 00:17:22 is you feel, you still feel the pull of stars
00:17:22 --> 00:17:24 around you, including the sun, but
00:17:24 --> 00:17:27 you're also under the influence of the
00:17:27 --> 00:17:30 galaxy itself. So our,
00:17:30 --> 00:17:32 uh, sun for example, is in orbit around the
00:17:32 --> 00:17:35 galactic centre. It's falling towards the
00:17:35 --> 00:17:38 galactic centre, but its velocity of, uh,
00:17:38 --> 00:17:40 200 kilometres per second,
00:17:41 --> 00:17:44 uh, actually about nearer
00:17:44 --> 00:17:47 to 250 kilometres per second around the
00:17:47 --> 00:17:49 centre of the galaxy. That's what's stopping
00:17:49 --> 00:17:51 it falling in towards the galactic centre
00:17:52 --> 00:17:54 goes around in about 200 million years.
00:17:55 --> 00:17:58 It's weird. Yeah, it is
00:17:58 --> 00:17:59 weird. It's very weird.
00:17:59 --> 00:18:01 Andrew Dunkley: I mean we're talking about that next with
00:18:01 --> 00:18:04 oddities in space, but that's one of them. I
00:18:04 --> 00:18:06 mean we've got this situation where these
00:18:06 --> 00:18:09 things been doing this for billions of years
00:18:09 --> 00:18:12 and that's not going to stop in a hurry.
00:18:12 --> 00:18:14 And, and even when our
00:18:15 --> 00:18:18 solar system ultimately has the
00:18:18 --> 00:18:21 sun go, you know, boom,
00:18:21 --> 00:18:23 it's still going to be happening like that,
00:18:24 --> 00:18:25 is it not?
00:18:26 --> 00:18:28 Professor Fred Watson: Yes, well, I mean the sun will
00:18:28 --> 00:18:31 swell, uh, to possibly
00:18:31 --> 00:18:33 engulf the inner planets, but the centre of
00:18:33 --> 00:18:36 its gravity is still where it is now,
00:18:36 --> 00:18:39 effectively. Um, so yes.
00:18:39 --> 00:18:42 Andrew Dunkley: What about maybe uh, you know, getting
00:18:42 --> 00:18:44 yourself into a Lagrange point?
00:18:45 --> 00:18:47 Professor Fred Watson: Yeah. So that's where those points
00:18:47 --> 00:18:50 are, where gravity and often
00:18:50 --> 00:18:52 centrifugal force balance out.
00:18:53 --> 00:18:55 So you've got this stable point
00:18:56 --> 00:18:58 M. You still. They're not that stable
00:18:58 --> 00:19:01 actually. The, you can tip one way or the
00:19:01 --> 00:19:03 other. It's more like a saddle in the
00:19:03 --> 00:19:06 gravitational pull, but they're still
00:19:06 --> 00:19:07 more stable.
00:19:07 --> 00:19:09 And I was actually going to mention that, um,
00:19:09 --> 00:19:12 that leads then to this idea of the
00:19:12 --> 00:19:14 interplanetary superhighway.
00:19:16 --> 00:19:19 The planets and their Lagrange points are
00:19:20 --> 00:19:22 kind of interlinked by these low energy
00:19:22 --> 00:19:25 pathways through the solar system. So if you
00:19:25 --> 00:19:28 push uh, an object into one of these low
00:19:28 --> 00:19:30 energy pathways, they are feeling the gravity
00:19:30 --> 00:19:33 of not just the sun and the Earth, but the
00:19:33 --> 00:19:35 moon and other planets as well. But they can
00:19:35 --> 00:19:37 wander their way along one of these pathways,
00:19:38 --> 00:19:40 uh, till they get to the other Lagrange
00:19:40 --> 00:19:42 point. And that's something that's been
00:19:42 --> 00:19:44 looked at for slow speed
00:19:44 --> 00:19:47 interplanetary travel, maybe for supply ships
00:19:47 --> 00:19:49 or something like that. But you're going to
00:19:49 --> 00:19:52 take decades to get to wherever you want to
00:19:52 --> 00:19:52 go.
00:19:52 --> 00:19:55 Andrew Dunkley: And by then, um, um, your
00:19:55 --> 00:19:57 iPhone's probably defunct.
00:19:58 --> 00:20:00 Uh, the technology would be too old.
00:20:00 --> 00:20:02 Professor Fred Watson: Yeah, yeah, yeah, yeah.
00:20:02 --> 00:20:05 Andrew Dunkley: Uh, so if you get far enough away from the,
00:20:05 --> 00:20:08 the pull of the Earth and the moon, the sun's
00:20:08 --> 00:20:09 going to grab you.
00:20:09 --> 00:20:11 Professor Fred Watson: You, you feel other things as well. Yeah,
00:20:11 --> 00:20:12 Jupiter's another.
00:20:12 --> 00:20:15 Andrew Dunkley: Oh yeah. Well it, yeah, it does not
00:20:15 --> 00:20:16 like being ignored.
00:20:16 --> 00:20:17 Professor Fred Watson: No it doesn't. That's right.
00:20:18 --> 00:20:21 Andrew Dunkley: In fact, that's another factor in our
00:20:21 --> 00:20:24 uh, solar system that Jupiter, because of its
00:20:24 --> 00:20:27 size and gravitational effect, is
00:20:28 --> 00:20:30 a good barrier for Earth when it comes to
00:20:31 --> 00:20:34 big, um, rocks heading in this direction.
00:20:34 --> 00:20:37 Professor Fred Watson: That's right. That's been um,
00:20:37 --> 00:20:40 postulated as one of the reasons why the
00:20:40 --> 00:20:42 Earth has evolved life because
00:20:42 --> 00:20:45 it's protected to some extent, particularly
00:20:45 --> 00:20:48 by comets. From comets, uh,
00:20:48 --> 00:20:50 by Jupiter, which turns a lot of comets
00:20:51 --> 00:20:54 from having fallen in from the Oort Cloud.
00:20:54 --> 00:20:55 They get grabbed by Jupiter's gravity and
00:20:55 --> 00:20:57 become what we call short period comets.
00:20:58 --> 00:21:01 Uh, so. But I've read papers that
00:21:01 --> 00:21:04 say the opposite is true. Jupiter's effect is
00:21:04 --> 00:21:07 not as protective as we'd like it to be. And
00:21:07 --> 00:21:09 maybe some of Jupiter's
00:21:10 --> 00:21:12 malevolence, uh, is when it redirects comets
00:21:12 --> 00:21:14 into short period orbits and we run into
00:21:14 --> 00:21:15 them.
00:21:16 --> 00:21:19 Andrew Dunkley: Yeah, not nice. Not nice at all.
00:21:19 --> 00:21:22 Um, so basically, doesn't matter where
00:21:22 --> 00:21:24 you go, you're going to be affected by some
00:21:24 --> 00:21:25 sort of gravity?
00:21:25 --> 00:21:27 Professor Fred Watson: That's right. Yes, you will. Even if you're
00:21:27 --> 00:21:29 deep in interstellar space, you'll still be
00:21:29 --> 00:21:31 feeling the effect of the gravity as a whole,
00:21:31 --> 00:21:32 as that
00:21:32 --> 00:21:35 Andrew Dunkley: means weightlessness is a myth in real terms.
00:21:35 --> 00:21:38 Professor Fred Watson: Um, yeah. Yes,
00:21:38 --> 00:21:41 in a sense it is. Uh,
00:21:42 --> 00:21:45 weight needs gravity. Um, and
00:21:46 --> 00:21:48 if you are experiencing forces
00:21:49 --> 00:21:52 that balance that, uh, force of gravity, then
00:21:52 --> 00:21:53 you're weightless and that's what happens
00:21:53 --> 00:21:55 when you're in orbit. There you go.
00:21:55 --> 00:21:58 Andrew Dunkley: All right, Good question. Thanks, Wayne.
00:21:58 --> 00:22:00 Lovely to hear from you. Our final question
00:22:00 --> 00:22:03 in this episode comes from Casey.
00:22:03 --> 00:22:05 Speaker C: Hi, guys, this is Casey from Colorado.
00:22:06 --> 00:22:08 There's a lot of weird stuff in space and I
00:22:08 --> 00:22:09 was wondering what some of your favourite
00:22:09 --> 00:22:12 oddities are. Thanks for the podcast
00:22:12 --> 00:22:15 and shout out to Huw for fixing the audio
00:22:15 --> 00:22:16 submissions. Bye.
00:22:17 --> 00:22:19 Andrew Dunkley: Thank you, Casey. Oh, Huw did some work. My
00:22:19 --> 00:22:22 goodness. Um,
00:22:22 --> 00:22:25 only took a couple of months. Um, no, thanks,
00:22:25 --> 00:22:27 Casey. Uh, oddities in space. I love this
00:22:27 --> 00:22:30 question, uh, because there are many,
00:22:30 --> 00:22:32 uh, if you go through an official list, of
00:22:32 --> 00:22:34 course, number one would be dark matter,
00:22:35 --> 00:22:36 number two would be dark energy.
00:22:37 --> 00:22:40 Um, those are obvious. Um,
00:22:41 --> 00:22:42 have you had a think about this one,
00:22:42 --> 00:22:43 Fred Watson? What have you come up with?
00:22:44 --> 00:22:45 Professor Fred Watson: Well, you know, we've just been talking about
00:22:45 --> 00:22:47 what, Something that's really odd and
00:22:47 --> 00:22:49 counterintuitive. A diamond star?
00:22:49 --> 00:22:50 Andrew Dunkley: Yeah.
00:22:50 --> 00:22:53 Professor Fred Watson: Um, a, uh, metal asteroid. That would
00:22:53 --> 00:22:56 be an oddity. We think Psyche is a metal
00:22:56 --> 00:22:58 asteroid. We'll find out when the Psyche
00:22:58 --> 00:23:00 spacecraft reaches Psyche. I, uh,
00:23:00 --> 00:23:03 think in 2031 or thereabouts. I think it's
00:23:03 --> 00:23:06 got a way to go yet. Uh, maybe not
00:23:06 --> 00:23:08 that far anyway. Sure, it's going to happen.
00:23:09 --> 00:23:11 Um, but I think
00:23:14 --> 00:23:16 some of the coincidences, uh, are
00:23:16 --> 00:23:19 oddities. And the one that always
00:23:19 --> 00:23:21 blows my mind is the coincidence of the sun
00:23:21 --> 00:23:24 and the moon looking to be the same size in
00:23:24 --> 00:23:27 the sky. That's a complete random thing
00:23:27 --> 00:23:29 with no physical
00:23:30 --> 00:23:32 mechanism that has caused that. And you've
00:23:32 --> 00:23:33 got these two objects which are the most
00:23:33 --> 00:23:35 prominent objects in our skies and they
00:23:35 --> 00:23:37 appear to be exactly the same size.
00:23:38 --> 00:23:40 Andrew Dunkley: And it's just a coincidental, just a
00:23:40 --> 00:23:42 coincidence proximity thing, isn't it?
00:23:42 --> 00:23:43 Professor Fred Watson: Very weird.
00:23:43 --> 00:23:45 Andrew Dunkley: Yeah. Actually I've got one that involves the
00:23:45 --> 00:23:48 moon I just, uh, found. And um,
00:23:48 --> 00:23:50 despite the fact that we look at it in the
00:23:50 --> 00:23:53 night sky and it's round, um, they say it's
00:23:53 --> 00:23:56 lemon shaped. Is that true?
00:23:56 --> 00:23:59 Professor Fred Watson: Um, it's
00:23:59 --> 00:24:02 got a slight deviation. Yes, that's right.
00:24:03 --> 00:24:05 Uh, ah, a bulge.
00:24:06 --> 00:24:07 Because it's always feeling,
00:24:08 --> 00:24:10 uh, because it always faces the same
00:24:11 --> 00:24:14 side to the Earth, I think it's slightly
00:24:15 --> 00:24:16 elongated in that direction.
00:24:17 --> 00:24:17 Andrew Dunkley: Okay.
00:24:17 --> 00:24:19 Professor Fred Watson: Um, I think that's the case. But
00:24:20 --> 00:24:23 in the, from the direction
00:24:23 --> 00:24:26 we see it, uh, because that lemon
00:24:26 --> 00:24:29 shape is towards us, what we see
00:24:29 --> 00:24:31 is an object that is almost perfectly
00:24:31 --> 00:24:34 circular. The moon. Very, very,
00:24:34 --> 00:24:37 very, very, uh, perfectly circular.
00:24:37 --> 00:24:39 Andrew Dunkley: And while we're talking about that, because
00:24:39 --> 00:24:41 you just popped into my head while you were
00:24:41 --> 00:24:43 talking, the sun in terms of,
00:24:44 --> 00:24:47 um, being spherical is almost the perfect
00:24:47 --> 00:24:48 circle, isn't it?
00:24:48 --> 00:24:51 Professor Fred Watson: It is, um, it differs from
00:24:51 --> 00:24:54 being spherical by something like 10
00:24:54 --> 00:24:57 kilometres and it's 1.4 million
00:24:57 --> 00:25:00 kilometres in diameter. That's right. And
00:25:00 --> 00:25:02 actually that raises another oddity in my
00:25:02 --> 00:25:05 mind, uh, which we've talked about many
00:25:05 --> 00:25:07 times. The mountains on neutron stars. Oh,
00:25:07 --> 00:25:10 yes. A few millimetres high.
00:25:10 --> 00:25:12 Andrew Dunkley: Yeah. That's just crazy, isn't it?
00:25:13 --> 00:25:16 Yeah. M. If you do
00:25:16 --> 00:25:18 Google searches for these things, it's
00:25:18 --> 00:25:21 millions of them. But uh, you know, if
00:25:21 --> 00:25:23 we stick to our solar system for a moment,
00:25:23 --> 00:25:25 um, a day on Mercury
00:25:26 --> 00:25:27 is twice as long as a year.
00:25:28 --> 00:25:29 Professor Fred Watson: Yes, that's right.
00:25:29 --> 00:25:32 Andrew Dunkley: Is that because of its, um, uh,
00:25:32 --> 00:25:35 what do you call it, um, tidal locking? Yes,
00:25:35 --> 00:25:36 tidal locking does sound.
00:25:36 --> 00:25:39 Professor Fred Watson: It's not quite tidally locked, but there's a
00:25:39 --> 00:25:41 relationship between the rotation and the
00:25:41 --> 00:25:44 revolution period, which is what you've said.
00:25:44 --> 00:25:46 Yeah, very weird. Yeah. Some of the
00:25:46 --> 00:25:48 planets have very weird things. I mean,
00:25:49 --> 00:25:51 um, Uranus on its side, that's an
00:25:51 --> 00:25:54 oddity. Um, that's very
00:25:54 --> 00:25:56 strange. But we think that's caused by a
00:25:56 --> 00:25:58 collision in the early solar system.
00:25:58 --> 00:26:01 Andrew Dunkley: Yeah. Uh, all the planets
00:26:01 --> 00:26:03 could fit between Earth and the moon.
00:26:03 --> 00:26:04 Professor Fred Watson: Yes, that's right.
00:26:04 --> 00:26:06 Andrew Dunkley: I mean that just blows my mind.
00:26:10 --> 00:26:12 Professor Fred Watson: It's actually. Go ahead.
00:26:12 --> 00:26:14 Andrew Dunkley: No, uh, that would make for some very
00:26:14 --> 00:26:16 interesting nights of observation, I imagine.
00:26:16 --> 00:26:19 Professor Fred Watson: Yeah. And it's an issue. It's um,
00:26:19 --> 00:26:22 quite interesting because the moon's, you
00:26:22 --> 00:26:24 know, the moon's orbit around the Earth is
00:26:24 --> 00:26:27 not circular, so sometimes it's nearer than
00:26:27 --> 00:26:29 at others. Perigee is when it's at its
00:26:29 --> 00:26:32 closest apogee is when it's at its furthest.
00:26:32 --> 00:26:35 Uh, the planets. The eight planets. Sorry,
00:26:35 --> 00:26:37 seven planets. Because the Earth's not part
00:26:37 --> 00:26:40 of it. Uh, they will only
00:26:40 --> 00:26:43 fit between the Earth and the Moon when
00:26:43 --> 00:26:46 the Moon is near apogee, if it's near
00:26:46 --> 00:26:48 perigee, you can't squeeze them in and it
00:26:48 --> 00:26:49 becomes a bit ugly, really.
00:26:49 --> 00:26:52 Andrew Dunkley: Yeah, I imagine so, yeah. Uh, I like
00:26:52 --> 00:26:55 this one. A teaspoon of neutron star
00:26:55 --> 00:26:57 weighs the same as the human population.
00:26:59 --> 00:27:01 I don't know how they figured that out.
00:27:01 --> 00:27:04 Professor Fred Watson: Uh, yes, yeah, uh,
00:27:04 --> 00:27:05 that's right.
00:27:06 --> 00:27:09 Andrew Dunkley: But, yeah, they're very heavy. Heavy.
00:27:10 --> 00:27:12 Professor Fred Watson: The one I like, the numerical one that I like
00:27:12 --> 00:27:15 is. And again, it's completely
00:27:15 --> 00:27:18 bizarre. It's got no reason for it. But the
00:27:18 --> 00:27:20 number of astronomical units and an
00:27:20 --> 00:27:22 astronomical unit is the distance from the
00:27:22 --> 00:27:25 sun to the earth, 150 million million
00:27:25 --> 00:27:27 kilometres. The number of astronomical units
00:27:27 --> 00:27:30 in a light year is almost
00:27:30 --> 00:27:33 exactly the same as the number of inches in
00:27:33 --> 00:27:33 a mile.
00:27:35 --> 00:27:38 It's very, very weird. 63 is the
00:27:38 --> 00:27:40 number, so there's a few digits that don't
00:27:40 --> 00:27:41 fit, but.
00:27:41 --> 00:27:44 Andrew Dunkley: Yeah, that's incredible. Uh, and then, and
00:27:44 --> 00:27:46 then there's these ones that sound, um,
00:27:46 --> 00:27:49 weird, but so logical when you
00:27:49 --> 00:27:51 explain it. That there are stars in the
00:27:51 --> 00:27:53 universe that we will never see.
00:27:54 --> 00:27:57 Professor Fred Watson: Yeah, uh, yes, because the light will never
00:27:57 --> 00:27:58 reach us. That's right.
00:27:59 --> 00:28:01 Andrew Dunkley: And that's probably why we'll never, ever
00:28:02 --> 00:28:04 find alien life too far away.
00:28:06 --> 00:28:09 Professor Fred Watson: Maybe. Maybe. Maybe the
00:28:09 --> 00:28:10 SETI people aren't giving up.
00:28:10 --> 00:28:13 Andrew Dunkley: No, they're not. Uh, now, I did say that,
00:28:13 --> 00:28:16 um, um, a day on Mercury is twice as long
00:28:16 --> 00:28:18 as a year. But on Venus,
00:28:19 --> 00:28:22 I think, um, it's a similar
00:28:22 --> 00:28:25 storey, isn't it? A day on Venus is longer
00:28:25 --> 00:28:25 than a year.
00:28:26 --> 00:28:27 Professor Fred Watson: Very long. Yeah. I can't remember the
00:28:27 --> 00:28:30 details, but Venus basically rotates the
00:28:30 --> 00:28:32 wrong way around. Uh, so
00:28:34 --> 00:28:36 its North Pole is facing downwards.
00:28:37 --> 00:28:40 That's what gives you the funny rotation. You
00:28:40 --> 00:28:43 define the north and south poles as
00:28:43 --> 00:28:45 being the direction or the point on a
00:28:45 --> 00:28:48 planet where, if you're looking at it from
00:28:48 --> 00:28:50 above, it's rotating anti clockwise.
00:28:51 --> 00:28:54 Because virtually everything in the solar
00:28:54 --> 00:28:56 system is rotating and revolving anti
00:28:56 --> 00:28:58 clockwise as seen from above the. The North
00:28:58 --> 00:29:01 Pole. Weird.
00:29:01 --> 00:29:03 Andrew Dunkley: Oh, you like this one, Casey? Neptune has
00:29:03 --> 00:29:05 only, uh, completed one orbit since it was
00:29:05 --> 00:29:08 discovered. M Very
00:29:08 --> 00:29:11 quirky, very quirky. And look, there must
00:29:11 --> 00:29:14 be billions of these.
00:29:14 --> 00:29:17 Like, um, you know, the, the weirdness of
00:29:17 --> 00:29:20 rogue planets or, um. Yeah, or the sun
00:29:20 --> 00:29:21 losing a billion kilos per second.
00:29:23 --> 00:29:24 Professor Fred Watson: That's right, yes.
00:29:24 --> 00:29:26 Andrew Dunkley: We found out the secret to that somebody
00:29:26 --> 00:29:27 could make billions of dollars on
00:29:27 --> 00:29:30 Professor Fred Watson: Earth, I reckon needs quite high
00:29:30 --> 00:29:31 temperatures to do that.
00:29:32 --> 00:29:34 Andrew Dunkley: Yeah, yeah. Um, and the list goes on.
00:29:34 --> 00:29:35 You got any more?
00:29:36 --> 00:29:39 Professor Fred Watson: Uh, well, you know, even black holes are
00:29:39 --> 00:29:41 things so weird. And the fact
00:29:41 --> 00:29:43 that we can actually, here's another
00:29:43 --> 00:29:45 statistic that's mind blowing.
00:29:45 --> 00:29:48 Um, it's the, the
00:29:48 --> 00:29:50 ligo, um,
00:29:50 --> 00:29:53 interferometer, which measures gravitational
00:29:53 --> 00:29:56 waves. The accuracy that we
00:29:56 --> 00:29:58 position it or know the mirrors to
00:29:59 --> 00:30:01 is something like a thousandth of the
00:30:01 --> 00:30:04 diameter of a proton. It's just incredible.
00:30:04 --> 00:30:06 But that's technology rather than space
00:30:06 --> 00:30:09 oddities really. That's technology. Yeah,
00:30:09 --> 00:30:10 that blows my mind too.
00:30:11 --> 00:30:14 Andrew Dunkley: And another one that's um, not talked about
00:30:14 --> 00:30:16 much. But our days are getting longer. I
00:30:16 --> 00:30:18 think there was an official report not so
00:30:18 --> 00:30:21 long ago about uh, the new length of a,
00:30:21 --> 00:30:23 of a day on Earth. But they uh, are getting
00:30:23 --> 00:30:26 longer because our rotation's
00:30:26 --> 00:30:27 slowing. Is that what it is?
00:30:28 --> 00:30:30 Professor Fred Watson: Yeah, it actually speeds up occasionally as
00:30:30 --> 00:30:33 well due to probably the movement of
00:30:33 --> 00:30:35 ice and things of that sort. But the overall
00:30:35 --> 00:30:37 trend is definitely slowing of the rotation.
00:30:38 --> 00:30:40 Andrew Dunkley: Yeah, there are so many of them, Casey.
00:30:40 --> 00:30:43 Um, and if, if anybody comes uh,
00:30:43 --> 00:30:45 across one they'd like to ask us about,
00:30:45 --> 00:30:47 please, uh, please send it in. But uh, thanks
00:30:47 --> 00:30:48 Casey. That was a lot of fun.
00:30:49 --> 00:30:51 Uh, and uh, that brings us to the end of the
00:30:51 --> 00:30:52 show, Fred Watson.
00:30:53 --> 00:30:55 Professor Fred Watson: Yes. Another show in the bag.
00:30:55 --> 00:30:58 Andrew Dunkley: And yeah, we're in the can as you, you know.
00:30:58 --> 00:31:00 That's the shop talk way of saying it.
00:31:00 --> 00:31:03 Professor Fred Watson: Shop talk. Yes, in the can. In the can.
00:31:03 --> 00:31:05 Um, and hopefully there'll be many more,
00:31:05 --> 00:31:05 Andrew.
00:31:06 --> 00:31:08 Andrew Dunkley: That would be lovely. Uh, we'll, we'll catch
00:31:08 --> 00:31:11 you on the next one in uh, a few days time.
00:31:11 --> 00:31:12 Fred Watson, thank you.
00:31:12 --> 00:31:14 Professor Fred Watson: Sounds like it. Thanks a lot. Take care.
00:31:14 --> 00:31:15 Andrew Dunkley: Professor Fred Watson Watson, astronomer at
00:31:15 --> 00:31:18 large. And thanks to Huw in the studio, uh,
00:31:18 --> 00:31:21 who couldn't be with us today due to
00:31:21 --> 00:31:24 some kind of oddity, a space
00:31:24 --> 00:31:26 oddity. Um, and don't uh,
00:31:26 --> 00:31:29 forget to visit us online at our website, uh,
00:31:29 --> 00:31:32 or on social media and send us your questions
00:31:32 --> 00:31:34 via the Ask me anything link at the top of
00:31:34 --> 00:31:37 our webpage, uh, in audio
00:31:37 --> 00:31:40 form or uh, as a text. And uh,
00:31:40 --> 00:31:42 don't forget to tell us who you are and where
00:31:42 --> 00:31:44 you're from. Always lovely to hear from you,
00:31:44 --> 00:31:46 wherever you are, are in the world and from
00:31:46 --> 00:31:48 me, Andrew Dunkley. Thanks for your company.
00:31:48 --> 00:31:50 We'll catch you on the next episode of Space
00:31:50 --> 00:31:53 Nuts. Bye bye. You've
00:31:53 --> 00:31:55 been listening to the Space Nuts podcast
00:31:57 --> 00:31:59 available at Apple Podcasts, Spotify,
00:32:00 --> 00:32:02 iHeartRadio or your favourite podcast
00:32:02 --> 00:32:04 player. You can also stream on
00:32:04 --> 00:32:06 demand@bytes.com this
00:32:06 --> 00:32:09 Professor Fred Watson: has been another quality podcast production
00:32:09 --> 00:32:10 from bytes.com.