Secure your online life...make sure your data stays yours alone. Do what we did and get NordVPN with our special deal which includes and extra 4 months for free and big savings, all at no risk to you. To check out the details visit www.nordvpn.com/spacenuts
Angular Momentum, Cosmic Time, and the Vastness of Space In this thought-provoking Q&A edition of Space Nuts, hosts Andrew Dunkley and Professor Fred Watson tackle a series of intriguing questions that delve into the complexities of the universe. From the nature of angular momentum in black holes to the perception of time across different gravitational fields, this episode promises to expand your understanding of cosmic phenomena.
Episode Highlights:
- Angular Momentum in Merging Black Holes: Mark from Baton Richie, Louisiana, asks whether two black holes spinning in opposite directions could result in a new black hole with zero angular momentum. Andrew and Fred Watson explain the nuances of angular momentum and how gravitational waves play a crucial role in this cosmic dance.
- The Age of the Universe and Gravitational Time Dilation: John poses a fascinating question about how the age of the universe might differ for someone near a supermassive black hole compared to an observer on Earth. The hosts discuss gravitational time dilation and the implications for our understanding of cosmic history.
- The Vastness of Space and Dark Matter: Pete shares his insights on the sparsity of matter in the galaxy and the uniform distribution of dark matter. Fred Watson elaborates on how dark matter influences galactic structures and why its effects are negligible on a solar system scale.
- The Big Leap and Speed Limits in the Universe: Martin Berman Gorvine challenges the hosts with a question about the theoretical possibility of circumventing the speed of light by accessing other universes. Andrew and Fred Watson navigate the complexities of this intriguing concept and its implications for our understanding of physics.
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. This is Space Nuts, A, uh, Q
00:00:02 --> 00:00:05 and A edition. My name is Andrew Dunkley,
00:00:05 --> 00:00:06 your host. Great to have your company. Hope
00:00:06 --> 00:00:08 you're well. Coming up on this episode,
00:00:08 --> 00:00:10 Fred Watson will be answering questions about
00:00:10 --> 00:00:13 angular momentum. The age of the
00:00:13 --> 00:00:16 universe versus the perception of time.
00:00:16 --> 00:00:18 That's an interesting one. The vastness of
00:00:18 --> 00:00:21 space and the big leap.
00:00:21 --> 00:00:23 Stick around. We'll deal with all of that
00:00:23 --> 00:00:26 coming up soon on this edition of space
00:00:26 --> 00:00:26 nuts.
00:00:26 --> 00:00:29 Mark Rabelais: 15 seconds. Guidance is internal.
00:00:29 --> 00:00:32 Professor Fred Watson: 10, 9. Ignition
00:00:32 --> 00:00:34 sequence. Star space nuts.
00:00:34 --> 00:00:35 Andrew Dunkley: 5, 4, 3.
00:00:35 --> 00:00:35 Professor Fred Watson: 2. 1.
00:00:36 --> 00:00:38 Andrew Dunkley: 2, 3, 4, 5, 5, 4, 3, 2,
00:00:38 --> 00:00:40 1. Space nuts.
00:00:40 --> 00:00:42 Mark Rabelais: Astronauts report it feels good.
00:00:43 --> 00:00:45 Andrew Dunkley: And we welcome him back once more. It's
00:00:45 --> 00:00:47 Professor Fred Watson Watson, astronomer at
00:00:47 --> 00:00:48 large. Hello, Fred Watson.
00:00:48 --> 00:00:50 Professor Fred Watson: Hello, Andrew. How you doing? Seeing you
00:00:50 --> 00:00:51 here.
00:00:51 --> 00:00:53 Andrew Dunkley: Yeah. So unusual.
00:00:53 --> 00:00:53 Professor Fred Watson: Doing all right?
00:00:53 --> 00:00:55 Andrew Dunkley: Seems like ages since we last spoke.
00:00:56 --> 00:00:57 Professor Fred Watson: Yes.
00:00:57 --> 00:00:58 Andrew Dunkley: Could have been a few seconds, though. Who
00:00:58 --> 00:01:01 knows? We will be talking about time shortly,
00:01:01 --> 00:01:03 so maybe the answer is in there.
00:01:04 --> 00:01:06 Um, let's get down to business.
00:01:06 --> 00:01:09 Uh, this first, uh, question comes from
00:01:09 --> 00:01:12 Mark. Now, uh, it's actually two
00:01:12 --> 00:01:14 questions about angular momentum. But, uh,
00:01:14 --> 00:01:15 Mark,
00:01:18 --> 00:01:21 he's sort of weeding this one out a little
00:01:21 --> 00:01:23 bit. Uh, so, um, let's find out what he
00:01:23 --> 00:01:24 wants to know.
00:01:25 --> 00:01:27 Mark Rabelais: Hello, fellas. My name is Mark
00:01:28 --> 00:01:31 and I reside in Baton Rouge,
00:01:31 --> 00:01:33 Louisiana. My question,
00:01:34 --> 00:01:37 my first question has to do with
00:01:37 --> 00:01:39 the two black holes that were
00:01:40 --> 00:01:43 very rapidly orbiting each other
00:01:43 --> 00:01:46 just before they merged. And each of
00:01:46 --> 00:01:48 those black holes presumably had
00:01:49 --> 00:01:52 its own angular momentum and
00:01:54 --> 00:01:57 was spinning, in a
00:01:57 --> 00:01:59 certain sense, either clockwise
00:01:59 --> 00:02:02 or counterclockwise. And,
00:02:02 --> 00:02:04 uh, my question is,
00:02:05 --> 00:02:07 if these two black holes,
00:02:08 --> 00:02:10 as unlikely as it might be,
00:02:11 --> 00:02:14 happened to be spinning
00:02:15 --> 00:02:16 with equal
00:02:18 --> 00:02:20 rates but in opposite
00:02:20 --> 00:02:23 directions in such a way that
00:02:23 --> 00:02:26 the net angular
00:02:26 --> 00:02:28 momentum of the combined system
00:02:30 --> 00:02:33 would be zero. Then would
00:02:33 --> 00:02:35 the final new black hole
00:02:36 --> 00:02:38 created have an angular momentum of zero?
00:02:39 --> 00:02:42 Not sure if I posed that correctly. But I'm
00:02:42 --> 00:02:44 sure you get what I'm saying, what I'm
00:02:44 --> 00:02:46 meaning here. Could the
00:02:46 --> 00:02:49 resulting black hole have a net angular
00:02:49 --> 00:02:51 momentum of zero? And if so,
00:02:52 --> 00:02:55 would that result in any unusual
00:02:56 --> 00:02:59 characteristics if a
00:02:59 --> 00:03:02 black hole was not spinning?
00:03:03 --> 00:03:06 Anyhow, that's my first question. My second
00:03:06 --> 00:03:07 question has to do with the
00:03:08 --> 00:03:10 universe writ large. Um,
00:03:11 --> 00:03:14 wouldn't the universe have a
00:03:14 --> 00:03:17 net angular momentum when the Big
00:03:17 --> 00:03:19 Bang occurred? I presume.
00:03:20 --> 00:03:22 Although I don't understand why there would
00:03:22 --> 00:03:24 be a non zero
00:03:25 --> 00:03:27 angular momentum of the entire universe.
00:03:29 --> 00:03:31 If the Big Bang
00:03:32 --> 00:03:34 was perfectly symmetric, the net
00:03:34 --> 00:03:37 angular momentum should be zero, should
00:03:37 --> 00:03:40 it not? And, uh,
00:03:40 --> 00:03:43 of course the Big Bang
00:03:43 --> 00:03:46 was not perfectly symmetric. And that is what
00:03:46 --> 00:03:47 I understand is the reason
00:03:48 --> 00:03:51 for the uh, clumping of matter
00:03:52 --> 00:03:55 as shown in the WMAP image.
00:03:55 --> 00:03:56 I guess I'm getting too
00:03:58 --> 00:04:01 off, off the beaten path here. But anyhow,
00:04:01 --> 00:04:04 uh, it has to. My question is,
00:04:04 --> 00:04:06 does the universe
00:04:07 --> 00:04:10 have a net angular momentum and
00:04:10 --> 00:04:12 what's the implications of that either way,
00:04:12 --> 00:04:15 whether it does or does not? Anyhow,
00:04:15 --> 00:04:17 see that's why I stay awake at night.
00:04:18 --> 00:04:21 Okay guys, love uh, your podcast. Uh,
00:04:22 --> 00:04:23 take care.
00:04:23 --> 00:04:26 Andrew Dunkley: Thank you Mark. Yeah, there's a lot packed
00:04:26 --> 00:04:29 into those, um, those ideas from Mark
00:04:29 --> 00:04:29 Fred Watson.
00:04:30 --> 00:04:32 Double barrel Question. Um, we'll start off
00:04:32 --> 00:04:35 with the two black holes merging with equal
00:04:35 --> 00:04:37 rate in opposite directions.
00:04:39 --> 00:04:40 Would uh, they
00:04:42 --> 00:04:44 achieve uh, zero angular
00:04:44 --> 00:04:47 momentum under those special circumstances?
00:04:49 --> 00:04:51 Professor Fred Watson: Uh, and the answer is yes, yes they could.
00:04:51 --> 00:04:54 Um, so there are two things at play here.
00:04:55 --> 00:04:58 Uh, one is the individual spin of each
00:04:58 --> 00:05:01 black hole. Uh, most black holes
00:05:01 --> 00:05:03 are spinning, uh, and
00:05:04 --> 00:05:07 so those two, um,
00:05:08 --> 00:05:10 the angular momentum of those two of each
00:05:10 --> 00:05:12 black hole when they collide,
00:05:13 --> 00:05:15 uh, it could be that they'll cancel out if
00:05:15 --> 00:05:17 they're rotating at the same rate in the
00:05:17 --> 00:05:19 opposite direction. Now normally, um,
00:05:19 --> 00:05:22 that's unlikely to happen because
00:05:23 --> 00:05:26 uh, you know, it will be very, very
00:05:26 --> 00:05:29 unusual to have two black
00:05:29 --> 00:05:32 holes with exactly the same rotation rate but
00:05:32 --> 00:05:35 one the negative of the other one rotating in
00:05:35 --> 00:05:37 the opposite direction. But it could happen.
00:05:37 --> 00:05:39 It could happen. But the bigger phenomenon
00:05:39 --> 00:05:42 uh, is actually the
00:05:43 --> 00:05:46 orbital angular momentum of the
00:05:46 --> 00:05:48 two black holes as they spin together.
00:05:49 --> 00:05:51 Uh, that's where most of the angular
00:05:51 --> 00:05:54 momentum in a binary black hole, a
00:05:54 --> 00:05:57 pair of black holes, that's where most of it
00:05:57 --> 00:05:59 lies, um, when they collide.
00:06:01 --> 00:06:03 What happens to that angular uh,
00:06:03 --> 00:06:06 momentum? Well it is radiated away
00:06:06 --> 00:06:09 in gravitational waves. And that's one of
00:06:09 --> 00:06:11 the things that is taken into account when
00:06:11 --> 00:06:14 people look at a gravitational wave signal
00:06:14 --> 00:06:16 coming from two colliding black holes.
00:06:16 --> 00:06:19 Um, the angular
00:06:19 --> 00:06:22 momentum gives rise to the um,
00:06:23 --> 00:06:25 change in angular momentum is one of the
00:06:25 --> 00:06:28 things that gives rise to the, to the uh,
00:06:28 --> 00:06:30 gravitational waves that are observed. And
00:06:30 --> 00:06:32 that's all modelled and all makes complete
00:06:32 --> 00:06:35 sense. Uh, so um, in particular
00:06:35 --> 00:06:37 though, um, that means that that's the
00:06:37 --> 00:06:40 biggest component of spin. The
00:06:40 --> 00:06:43 individual spin of each black holes is a
00:06:43 --> 00:06:45 smaller one. Uh, but still,
00:06:46 --> 00:06:49 um, it basically is uh, exactly
00:06:49 --> 00:06:52 as Mark has postulated. Uh, they
00:06:52 --> 00:06:55 could cancel out completely what happens to
00:06:55 --> 00:06:58 the angular momentum. Once again it, it is
00:06:58 --> 00:07:01 radiated out in the form of gravitational
00:07:01 --> 00:07:03 waves. That's where the angular momentum
00:07:03 --> 00:07:05 goes. It's a form of energy and that comes
00:07:05 --> 00:07:07 out as energy that we can now measure with
00:07:07 --> 00:07:09 our ah, gravitational wave detectors.
00:07:09 --> 00:07:12 And turning to part two, which I
00:07:12 --> 00:07:15 Andrew Dunkley: think, yes, the universe
00:07:15 --> 00:07:18 um, yeah. Ah, assuming that
00:07:18 --> 00:07:21 it radiated, radiated out in all directions
00:07:21 --> 00:07:23 simultaneously in a spherical
00:07:23 --> 00:07:26 way, um, would it have and
00:07:27 --> 00:07:29 should it not have m net 0 angular momentum?
00:07:31 --> 00:07:34 Professor Fred Watson: And apparently it does, uh, in the
00:07:34 --> 00:07:36 sense that, uh, it has never.
00:07:37 --> 00:07:40 There's no evidence for a
00:07:40 --> 00:07:42 rotation of the universe as a whole.
00:07:42 --> 00:07:45 Um, Mark, again is on absolutely the right
00:07:45 --> 00:07:47 track because, uh, if there was
00:07:48 --> 00:07:50 a rotation in the universe, you'd
00:07:50 --> 00:07:52 expect to see particular
00:07:53 --> 00:07:56 patterns within the cosmic microwave
00:07:56 --> 00:07:58 background radiation, which is what he
00:07:58 --> 00:08:01 mentioned in relation to wmap, the Wilkinson
00:08:01 --> 00:08:03 Microwave Wave Anisotropy Probe.
00:08:03 --> 00:08:06 And, uh, we don't see that. We don't see, um,
00:08:07 --> 00:08:09 characteristics that would suggest that the
00:08:09 --> 00:08:12 universe is rotating. So it looks as though
00:08:12 --> 00:08:15 there was enough symmetry in the Big Bang
00:08:15 --> 00:08:18 itself, uh, that no rotation
00:08:18 --> 00:08:20 was imparted to the universe. One of the
00:08:20 --> 00:08:23 other issues with this, of course, is
00:08:23 --> 00:08:26 if it was rotating, then you
00:08:26 --> 00:08:28 have to, um,
00:08:29 --> 00:08:32 basically invoke a central point,
00:08:32 --> 00:08:35 uh, and an absolute reference frame. And
00:08:35 --> 00:08:38 neither of these things are permitted in our,
00:08:38 --> 00:08:41 uh, normal cosmological theories. Uh,
00:08:41 --> 00:08:43 so it's just as well that it's not there.
00:08:44 --> 00:08:46 And it's the fact that we don't see any
00:08:46 --> 00:08:48 rotation that allows us to ignore the
00:08:48 --> 00:08:51 idea of an absolute reference frame. Uh, we
00:08:51 --> 00:08:53 just take the universe as a whole.
00:08:53 --> 00:08:56 Andrew Dunkley: It's like a snow globe. Like the snow
00:08:56 --> 00:08:58 globe's got no angular momentum, but
00:08:58 --> 00:09:00 everything inside's doing all sorts of busy
00:09:00 --> 00:09:00 stuff.
00:09:01 --> 00:09:04 Professor Fred Watson: Uh, yes, that's right. That's a very nice way
00:09:04 --> 00:09:06 to put it. Um, you'll go far, Andrew, with
00:09:07 --> 00:09:08 analogues like that.
00:09:08 --> 00:09:10 Andrew Dunkley: I went to a tourist shop to figure that out.
00:09:10 --> 00:09:11 Yeah,
00:09:13 --> 00:09:16 Professor Fred Watson: you've got to choose the right snow globe.
00:09:16 --> 00:09:16 That's right.
00:09:17 --> 00:09:19 Andrew Dunkley: Did you know that people who invented snow
00:09:19 --> 00:09:22 globes never, ever, to this day, it's still
00:09:22 --> 00:09:24 a trade secret revealed what the glittery
00:09:24 --> 00:09:26 stuff inside a snow globe is.
00:09:27 --> 00:09:29 Professor Fred Watson: No, I didn't know. That's true.
00:09:29 --> 00:09:32 Andrew Dunkley: Look m it up. The
00:09:32 --> 00:09:34 original inventors and the family that
00:09:34 --> 00:09:37 started it still has control
00:09:37 --> 00:09:40 of, um, uh, the invention to this
00:09:40 --> 00:09:42 day have never ever
00:09:42 --> 00:09:45 revealed what is inside a snow
00:09:45 --> 00:09:47 globe. What makes all the glittery
00:09:48 --> 00:09:50 snow like effect. They've never
00:09:50 --> 00:09:53 told anybody. Uh, I think it's the same
00:09:53 --> 00:09:56 stuff they put on KFC nuggets. But
00:09:56 --> 00:09:59 I, uh, could be wrong. I could be
00:09:59 --> 00:10:01 wrong. Secret herbs and spices,
00:10:01 --> 00:10:04 maybe. Uh, thank you, Mark. A very thoughtful
00:10:04 --> 00:10:07 question. Uh, and it sounds like, um, you're
00:10:07 --> 00:10:09 on the money so you can actually go to sleep
00:10:09 --> 00:10:12 tonight. Uh, well done.
00:10:12 --> 00:10:14 Uh, our next question, Fred Watson, comes
00:10:14 --> 00:10:16 from John. Does the age of the universe
00:10:16 --> 00:10:19 depend on the gravity well, that you
00:10:19 --> 00:10:22 exist within. If Andrew was living on a
00:10:22 --> 00:10:24 planet orbiting a super massive black hole,
00:10:24 --> 00:10:27 eg. Sagittarius, a star, uh,
00:10:27 --> 00:10:30 time would be slower for him relative to
00:10:30 --> 00:10:32 Fred Watson living on Earth. Would Andrew
00:10:32 --> 00:10:34 then calculate the age of the universe, the
00:10:34 --> 00:10:36 universe to be less than what Fred Watson
00:10:36 --> 00:10:39 does? That one comes from John. That's a good
00:10:39 --> 00:10:41 one. That's a what if question.
00:10:43 --> 00:10:46 Professor Fred Watson: It is. We should try it out
00:10:46 --> 00:10:48 one day. Yeah, uh, you can be the one
00:10:49 --> 00:10:50 going and living on the black hole.
00:10:50 --> 00:10:53 Andrew Dunkley: Yeah, uh, that I don't think it'd be a very
00:10:53 --> 00:10:56 long lived situation. But uh, you know,
00:10:56 --> 00:10:58 yeah, I'm happy to, happy to give it a
00:10:58 --> 00:10:59 whirl.
00:11:00 --> 00:11:02 Professor Fred Watson: So um, turning to the um,
00:11:03 --> 00:11:05 um, the answer to John's uh,
00:11:05 --> 00:11:08 conundrum. Uh, the, the answer is yes, there
00:11:08 --> 00:11:11 is gravitational time dilation.
00:11:11 --> 00:11:14 So if you were, you know, if
00:11:14 --> 00:11:17 you were hanging around a black hole, you'd
00:11:17 --> 00:11:20 think the universe would have a
00:11:20 --> 00:11:22 younger age than an
00:11:22 --> 00:11:24 observer in deep empty space.
00:11:25 --> 00:11:26 But uh,
00:11:28 --> 00:11:31 it is a small effect
00:11:31 --> 00:11:34 compared with the size of the universe
00:11:34 --> 00:11:37 at uh, large. So what we do is
00:11:37 --> 00:11:40 we treat the age of the universe as a,
00:11:40 --> 00:11:43 basically as a
00:11:43 --> 00:11:46 universal constant. And you can sort
00:11:46 --> 00:11:48 of imagine um, when we look at
00:11:48 --> 00:11:50 for example the cosmic microwave background
00:11:50 --> 00:11:53 radiation, we look around the whole sky
00:11:53 --> 00:11:56 and we see the flash of the Big
00:11:56 --> 00:11:59 Bang and we assume that it's the same age in
00:11:59 --> 00:12:02 all directions. Uh, and
00:12:02 --> 00:12:04 that's basically what we do.
00:12:04 --> 00:12:07 We take, we take uh, the
00:12:08 --> 00:12:10 flash of the Big Bang as being our uh,
00:12:10 --> 00:12:12 yardstick for the 13.8 billion
00:12:12 --> 00:12:15 years age of the universe. And
00:12:15 --> 00:12:18 that's so it irons out, if I can put it that
00:12:18 --> 00:12:21 way. This is the global view that irons out
00:12:21 --> 00:12:23 all the local funny uh, gravitational
00:12:23 --> 00:12:25 effects like you hanging around a black hole
00:12:25 --> 00:12:28 and seeing a younger universe. This is
00:12:29 --> 00:12:31 um, what you might call um, a
00:12:31 --> 00:12:34 measurement made in a, in a, in a
00:12:34 --> 00:12:36 preferred reference frame. You're just
00:12:36 --> 00:12:38 talking about reference frames in terms of a
00:12:38 --> 00:12:40 rotating universe. This is the same issue.
00:12:41 --> 00:12:43 This is the, the sort of standard reference
00:12:43 --> 00:12:45 frame of the universe kind of defined by the
00:12:45 --> 00:12:48 cosmic microwave background radiation. Um,
00:12:48 --> 00:12:51 and so gravitational effects on that whole
00:12:52 --> 00:12:54 picture are ah, minimal compared with what
00:12:54 --> 00:12:57 might be felt when you were very close to
00:12:57 --> 00:12:59 something with a very high gravity.
00:13:00 --> 00:13:03 Andrew Dunkley: Okay, all right. I, I was surprised that
00:13:03 --> 00:13:06 it went the way you said because I was,
00:13:06 --> 00:13:08 I thought you were going to say no. For me,
00:13:08 --> 00:13:10 time will pass as it would anywhere else.
00:13:10 --> 00:13:13 It's just, you know, to the observer it would
00:13:13 --> 00:13:15 be different. You wouldn't be moving.
00:13:16 --> 00:13:18 Um, but, no but
00:13:19 --> 00:13:21 from the inside it would
00:13:22 --> 00:13:24 Be different because what you're looking at
00:13:24 --> 00:13:27 on the outside would
00:13:27 --> 00:13:30 age, uh, slower, therefore seem younger. Is
00:13:30 --> 00:13:31 that what you said?
00:13:31 --> 00:13:34 Professor Fred Watson: Yes, that's right. So, so the, um.
00:13:35 --> 00:13:37 It is, it's, you know, you're, you're
00:13:37 --> 00:13:39 observing from a different reference frame
00:13:39 --> 00:13:41 when you're hanging around the black hole.
00:13:42 --> 00:13:45 Uh, and that's. And so that it's. I mean, we
00:13:45 --> 00:13:46 normally think, you know, we talk about
00:13:46 --> 00:13:49 people falling into a black hole and they.
00:13:49 --> 00:13:52 Time stops on the event horizon
00:13:52 --> 00:13:54 as they cross the event horizon.
00:13:54 --> 00:13:57 Uh, but that's how we normally think about
00:13:57 --> 00:14:00 these things. But if you, if you, if you
00:14:00 --> 00:14:03 yourself are in the black hole, then it looks
00:14:03 --> 00:14:04 as though the whole universe is doing
00:14:04 --> 00:14:07 different things like becoming younger
00:14:07 --> 00:14:08 and things of that sort.
00:14:08 --> 00:14:09 Andrew Dunkley: Extraordinary.
00:14:09 --> 00:14:10 Professor Fred Watson: Yeah.
00:14:10 --> 00:14:11 Andrew Dunkley: It's just such a weird place, isn't
00:14:11 --> 00:14:13 Professor Fred Watson: it, when you're very weird. Yes.
00:14:15 --> 00:14:17 Andrew Dunkley: All right, John, Uh, great question. And, uh,
00:14:17 --> 00:14:20 yeah, the answer was yes. This is Space Nuts
00:14:20 --> 00:14:22 with Andrew Dunkley and Professor Fred Watson
00:14:22 --> 00:14:24 Watson. A Q and A edition.
00:14:29 --> 00:14:30 Mark Rabelais: Space Nuts.
00:14:30 --> 00:14:33 Andrew Dunkley: Okay, Fred Watson, our, uh, next storey
00:14:33 --> 00:14:36 comes from Pete, who says hi.
00:14:36 --> 00:14:38 Great show. Well done. Oh, thank you.
00:14:39 --> 00:14:41 Um, in trying to understand the impact of
00:14:41 --> 00:14:44 dark matter matter on the stability of the
00:14:44 --> 00:14:46 galaxy, I was perplexed by the lack of
00:14:46 --> 00:14:49 reported impact on our solar system. And
00:14:49 --> 00:14:51 then closer to home, the Earth, the moon and
00:14:51 --> 00:14:54 space traffic, uh, that
00:14:54 --> 00:14:57 led me to a, uh, realisation that whilst we
00:14:57 --> 00:15:00 see visual images of galaxies that look full,
00:15:00 --> 00:15:03 that in reality, if all the
00:15:03 --> 00:15:05 baryonic matter in the galaxy was accumulated
00:15:05 --> 00:15:08 together, it would represent a minuscule
00:15:08 --> 00:15:10 percentage of the volume of the galaxy. That
00:15:10 --> 00:15:13 the galaxy may have 100 billion stars
00:15:13 --> 00:15:16 but is basically empty. Dark
00:15:16 --> 00:15:18 matter, whatever it turns out to be, is
00:15:18 --> 00:15:21 likewise so sparsely distributed that
00:15:21 --> 00:15:24 it is undetectable at the solar system
00:15:24 --> 00:15:27 level. Maybe the professor, uh, could expand
00:15:27 --> 00:15:29 on these comments for the benefit of all of
00:15:29 --> 00:15:32 us who struggle to grasp the vastness of
00:15:32 --> 00:15:34 empty space that constitutes the galaxy and
00:15:34 --> 00:15:37 ultimately the universe. Many thanks from
00:15:37 --> 00:15:40 Pete. What do you reckon, Fred Watson?
00:15:40 --> 00:15:43 Professor Fred Watson: Well, Pete's right as well. Uh, we've done
00:15:43 --> 00:15:45 really well today. We've had three
00:15:45 --> 00:15:47 speculations, all of which have turned out to
00:15:47 --> 00:15:50 be on the money. Um, it's the fact that,
00:15:50 --> 00:15:53 um, dark matter, whilst we know it,
00:15:53 --> 00:15:55 clumps. It clumps on
00:15:55 --> 00:15:58 scales that are much bigger than the galaxy.
00:15:58 --> 00:16:01 So our galaxy is in a blob of dark
00:16:01 --> 00:16:04 matter that, um, actually, uh, is
00:16:05 --> 00:16:08 much, uh, you know, much bigger
00:16:08 --> 00:16:10 than the galaxy itself. So what that means
00:16:10 --> 00:16:13 is that, um, exactly
00:16:13 --> 00:16:16 as Pete says, you've got a uni,
00:16:17 --> 00:16:19 to all intents and purposes, within the solar
00:16:19 --> 00:16:21 system. And actually within the
00:16:21 --> 00:16:24 galaxy itself too, you've got the kind of
00:16:24 --> 00:16:27 uniform background of dark matter whose
00:16:27 --> 00:16:30 gravitational influence, uh, is
00:16:30 --> 00:16:33 there, but is kind of acts
00:16:33 --> 00:16:36 equally in all directions to stuff that's
00:16:36 --> 00:16:39 immersed in it, if I can put it that way. So,
00:16:39 --> 00:16:42 yes, the solar
00:16:42 --> 00:16:45 system is full of dark matter, um, but it's
00:16:45 --> 00:16:47 effectively uniform. It's just like a
00:16:47 --> 00:16:50 background uniformity, which is why
00:16:52 --> 00:16:53 when we calculate the orbits of planets and
00:16:53 --> 00:16:55 things like that, we can completely ignore it
00:16:56 --> 00:16:59 because it's essentially a flat
00:16:59 --> 00:17:02 space of, uh, of uniform
00:17:02 --> 00:17:05 gravitational influence, if I can put it that
00:17:05 --> 00:17:06 way. I don't think I'm explaining that very
00:17:06 --> 00:17:08 well, but that's the bottom line. And it's
00:17:08 --> 00:17:10 basically. It's exactly what Pete said.
00:17:12 --> 00:17:13 Andrew Dunkley: And what did he say?
00:17:15 --> 00:17:17 Professor Fred Watson: He said what I've just said,
00:17:19 --> 00:17:21 that the, the blob of dark matter that the
00:17:21 --> 00:17:24 galaxy's in is effectively uniform on
00:17:24 --> 00:17:27 distances, uh, comparable with the, the
00:17:27 --> 00:17:29 solar system and in fact on distances
00:17:29 --> 00:17:31 comparable with the stars in the galaxy as
00:17:31 --> 00:17:31 well.
00:17:31 --> 00:17:34 Andrew Dunkley: Yeah, it's seems to be a need of
00:17:34 --> 00:17:37 dark matter to have stuff
00:17:37 --> 00:17:38 to hang around.
00:17:39 --> 00:17:41 Professor Fred Watson: Yes. With. We think it's the other way
00:17:41 --> 00:17:43 around. We think that the stuff gravitated
00:17:43 --> 00:17:46 inwards, being pulled because of the
00:17:46 --> 00:17:48 glut. The dark matter. That's right. And
00:17:48 --> 00:17:51 that's what caused galaxies to form.
00:17:51 --> 00:17:54 Uh, sort of built on a scaffolding of dark
00:17:54 --> 00:17:56 matter, which was what was created in the big
00:17:56 --> 00:17:56 bone.
00:17:57 --> 00:18:00 Andrew Dunkley: Right. Wow. Okay. That
00:18:00 --> 00:18:02 just makes it even more mysterious
00:18:02 --> 00:18:05 really, doesn't it?
00:18:06 --> 00:18:09 Professor Fred Watson: Um, well, it neatly explains
00:18:09 --> 00:18:12 why galaxies are there because that, you
00:18:12 --> 00:18:14 know, it's very convenient. It is convenient
00:18:14 --> 00:18:17 to have galaxies. Yeah. That the,
00:18:17 --> 00:18:20 this sort of web like structure, uh,
00:18:20 --> 00:18:21 which we think dark matter,
00:18:22 --> 00:18:25 um, you know, that was the shape of dark
00:18:25 --> 00:18:27 matter. It was like a honeycomb of material,
00:18:28 --> 00:18:30 except it's not material as we know it.
00:18:30 --> 00:18:33 Um, that web like structure is actually
00:18:33 --> 00:18:35 a direct consequence of the Big bang. It's
00:18:35 --> 00:18:38 what we expect. It's what we expect the big
00:18:38 --> 00:18:40 bang to do. Um, and, uh,
00:18:40 --> 00:18:42 Jordi agrees with that.
00:18:42 --> 00:18:43 Andrew Dunkley: Yes, he does have noticed.
00:18:43 --> 00:18:45 Professor Fred Watson: Yeah, he's upset because.
00:18:46 --> 00:18:48 Andrew Dunkley: Yeah, he, he's, he's dealing with a dark
00:18:48 --> 00:18:51 matter by the sound of it. Poor old
00:18:51 --> 00:18:52 Jordy.
00:18:52 --> 00:18:54 Professor Fred Watson: Jordy. It's all right. It's okay.
00:18:54 --> 00:18:55 Andrew Dunkley: It's okay.
00:18:55 --> 00:18:57 Professor Fred Watson: Yeah, his tail's gone up again. It was very
00:18:57 --> 00:18:59 down the second ago. Yeah.
00:18:59 --> 00:19:01 Andrew Dunkley: We were talking about dark matter and
00:19:01 --> 00:19:03 Professor Fred Watson: that's, that's what he is.
00:19:03 --> 00:19:03 Andrew Dunkley: Yes.
00:19:03 --> 00:19:06 Professor Fred Watson: Very dark indeed. Probably the blackest thing
00:19:06 --> 00:19:07 in the whole house. Yes.
00:19:09 --> 00:19:12 Andrew Dunkley: Um, I, I know there's. We get so
00:19:12 --> 00:19:14 many Questions about dark matter and, and
00:19:14 --> 00:19:17 dark energy and black holes. It's, um,
00:19:18 --> 00:19:21 probably the top three things that people ask
00:19:21 --> 00:19:24 us about. And, and
00:19:24 --> 00:19:25 Jordy. We ask about Georgie all the time.
00:19:25 --> 00:19:28 Sarah. Um, but, yeah, you know,
00:19:30 --> 00:19:33 just never ceases to amaze me
00:19:33 --> 00:19:36 that there are, like,
00:19:36 --> 00:19:39 how long ago didn't we even know about dark
00:19:39 --> 00:19:41 matter? And now we've started thinking, well,
00:19:41 --> 00:19:42 okay, it's, it's doing a lot more than we
00:19:43 --> 00:19:46 ever anticipated. And now we seem to have a
00:19:46 --> 00:19:48 total reliance on it to keep everything
00:19:48 --> 00:19:49 together. It's the, it's the glue of the
00:19:49 --> 00:19:50 universe.
00:19:51 --> 00:19:53 Professor Fred Watson: Um, it's a good way to put it.
00:19:53 --> 00:19:54 Andrew Dunkley: Yeah, yeah.
00:19:56 --> 00:19:59 Professor Fred Watson: What? Write a book. Should be on
00:19:59 --> 00:19:59 radio.
00:19:59 --> 00:20:00 Andrew Dunkley: All right, yes,
00:20:03 --> 00:20:06 maybe one day. Uh, but, um. You think they'll
00:20:06 --> 00:20:07 ever crack it? I've probably asked that
00:20:07 --> 00:20:10 question many times, but, um, you know,
00:20:10 --> 00:20:12 do you think they'll ever figure out what
00:20:12 --> 00:20:14 this is and how it all came to be?
00:20:15 --> 00:20:17 Professor Fred Watson: Yeah, I think so.
00:20:17 --> 00:20:19 And, you know, there's, there's ideas buzzing
00:20:19 --> 00:20:20 around all the time. We talked not very long
00:20:20 --> 00:20:23 ago about the idea that suddenly people are
00:20:23 --> 00:20:26 suspecting that, um, primordial
00:20:26 --> 00:20:29 black holes might be a reality. And, uh, they
00:20:29 --> 00:20:31 can come in any size you like, rather than
00:20:31 --> 00:20:33 have to be bigger than the size of the sun.
00:20:34 --> 00:20:36 Uh, and so one that's smaller than the sun
00:20:36 --> 00:20:39 has been found. Uh, and that suggests that
00:20:39 --> 00:20:41 primordial black holes may exist. And that
00:20:41 --> 00:20:43 might open the whole debate again about
00:20:43 --> 00:20:46 whether, uh, dark matter is made of
00:20:46 --> 00:20:49 machos or wimps, uh, with the machos
00:20:49 --> 00:20:51 being massive compact halo objects. That's
00:20:52 --> 00:20:54 things like black holes. And the wimps are
00:20:54 --> 00:20:56 weakly interacting massive particles, which
00:20:56 --> 00:20:59 is kind of the preferred view now.
00:20:59 --> 00:21:01 And then on top of that, there's the
00:21:01 --> 00:21:03 possibility that we've got it all wrong
00:21:03 --> 00:21:05 anyway, uh, that it might be
00:21:05 --> 00:21:08 actually modified Newtonian dynamics that
00:21:08 --> 00:21:11 work. So it's
00:21:11 --> 00:21:14 still some open questions with regard to dark
00:21:14 --> 00:21:15 matter. And we've been thinking about this
00:21:15 --> 00:21:18 seriously, uh, for almost
00:21:18 --> 00:21:21 the last 50 years. It was 1978 when Vera
00:21:21 --> 00:21:24 Rubin's observations really hit home,
00:21:24 --> 00:21:26 that there was something very basic about the
00:21:26 --> 00:21:27 universe that we didn't understand.
00:21:29 --> 00:21:31 Andrew Dunkley: Like how wasn't it throwing itself to pieces?
00:21:31 --> 00:21:32 Professor Fred Watson: Yes, that's right.
00:21:32 --> 00:21:33 Andrew Dunkley: That was the question.
00:21:34 --> 00:21:36 Professor Fred Watson: That question was asked by Ken Freeman, who's
00:21:36 --> 00:21:38 an Australian astronomer. He, he, uh,
00:21:38 --> 00:21:41 published a paper in 1970 which was
00:21:41 --> 00:21:43 saying galaxies are rotating too fast to stay
00:21:43 --> 00:21:46 together. Yeah, um,
00:21:46 --> 00:21:49 Vera postulated that there are halos of stuff
00:21:49 --> 00:21:51 that keep them together. And that's when the
00:21:51 --> 00:21:53 whole dark matter, um, vogue, if I can
00:21:53 --> 00:21:56 put it that way, started yeah, and it's, it's
00:21:56 --> 00:21:59 Andrew Dunkley: still the big question, isn't it? Uh,
00:21:59 --> 00:22:01 one of several, but, yeah, one of the biggest
00:22:01 --> 00:22:04 ones. Uh, thank you, Pete. Great question,
00:22:04 --> 00:22:06 and, uh, thanks for sending it in.
00:22:09 --> 00:22:11 Okay, we've had a problem here.
00:22:11 --> 00:22:11 Professor Fred Watson: This is Houston.
00:22:11 --> 00:22:12 Andrew Dunkley: Say again, please.
00:22:16 --> 00:22:18 Okay, standby 13. We're looking at it.
00:22:18 --> 00:22:21 Spacebuds, our final question
00:22:21 --> 00:22:23 comes from, uh, uh, you were saying,
00:22:23 --> 00:22:24 Fred Watson, that we. We've been right on the
00:22:24 --> 00:22:27 money. These questions have been, you know,
00:22:27 --> 00:22:29 spot on until now.
00:22:30 --> 00:22:33 Berman Gorvine: Hello, space nuts. Uh,
00:22:34 --> 00:22:36 Martin Berman Gorvine here, writer
00:22:37 --> 00:22:39 extraordinaire in many
00:22:39 --> 00:22:42 genres, here to accept
00:22:43 --> 00:22:45 Professor Watson's thanks
00:22:46 --> 00:22:49 for the Bee Gees
00:22:49 --> 00:22:52 quip. And I'm asking
00:22:52 --> 00:22:54 today about another
00:22:55 --> 00:22:57 BG brother. This
00:22:57 --> 00:23:00 one, uh, may not even exist,
00:23:01 --> 00:23:04 and I know that, nonetheless, you
00:23:04 --> 00:23:06 have gotten questions about him before.
00:23:07 --> 00:23:10 And that would be Peel, Give.
00:23:11 --> 00:23:13 Yes, Peel, Give,
00:23:14 --> 00:23:16 otherwise known as
00:23:17 --> 00:23:18 the Big Leap.
00:23:20 --> 00:23:22 Can you somehow
00:23:24 --> 00:23:25 circumvent
00:23:27 --> 00:23:30 the absolute speed
00:23:30 --> 00:23:31 limit of
00:23:33 --> 00:23:36 the speed of light in the
00:23:36 --> 00:23:39 universe by having
00:23:39 --> 00:23:42 a, ah, quick, uh, dodge out
00:23:42 --> 00:23:45 into another universe where the speed
00:23:45 --> 00:23:48 speed of light is arbitrarily high,
00:23:48 --> 00:23:51 which is a staple of
00:23:51 --> 00:23:54 science fiction? Um,
00:23:54 --> 00:23:56 is this theoretically possible?
00:23:57 --> 00:24:00 Um, and even if it were,
00:24:00 --> 00:24:03 would it be possible to go have
00:24:03 --> 00:24:06 a visit with Mr. Peel Gibb
00:24:06 --> 00:24:08 without being spaghettified
00:24:09 --> 00:24:12 and turned into, um,
00:24:12 --> 00:24:14 mush of particles without even
00:24:15 --> 00:24:16 marinara thought?
00:24:17 --> 00:24:19 Can't wait for the answer.
00:24:20 --> 00:24:22 Berman Gourvine, over
00:24:23 --> 00:24:24 and out.
00:24:26 --> 00:24:28 Andrew Dunkley: Uh, thank you, Martin. I think he just
00:24:28 --> 00:24:31 brought our, um, podcast episode back
00:24:31 --> 00:24:33 to kind of the average
00:24:34 --> 00:24:36 sphere in terms of. No, no,
00:24:37 --> 00:24:39 I'm kidding. Um, love you, Martin. Love
00:24:39 --> 00:24:42 you very much. Um, Peel Gibb. Peel
00:24:42 --> 00:24:45 Gibb. The, um, the Big leap. So
00:24:45 --> 00:24:48 I think I'm just trying to. I'm scratching my
00:24:48 --> 00:24:51 head here. I, I think he's asking, is
00:24:51 --> 00:24:53 the absolute speed limit of light
00:24:53 --> 00:24:56 constant? If you could go and
00:24:56 --> 00:24:59 visit another. Another universe in
00:24:59 --> 00:25:00 comparison. Is that what he meant?
00:25:01 --> 00:25:03 Professor Fred Watson: That's the bottom line of this question.
00:25:03 --> 00:25:03 Yeah.
00:25:04 --> 00:25:06 Andrew Dunkley: One answer for this, and it could be one or
00:25:06 --> 00:25:07 the other.
00:25:07 --> 00:25:08 Professor Fred Watson: Well, it is. It's, It's. No,
00:25:10 --> 00:25:13 but, um, you know, just thinking aloud on
00:25:13 --> 00:25:15 that. So, uh,
00:25:15 --> 00:25:18 first of all, it is possible that in, if
00:25:18 --> 00:25:20 there were other universes, some of the
00:25:20 --> 00:25:22 fundamental physical constants might be
00:25:22 --> 00:25:24 different. The charge on the electron might
00:25:24 --> 00:25:26 be different, the speed of light might be
00:25:26 --> 00:25:28 different. Um, that's
00:25:29 --> 00:25:31 something we, we know so little about other
00:25:31 --> 00:25:33 universes, mainly because we don't know
00:25:33 --> 00:25:34 whether they exist, and there isn't really
00:25:34 --> 00:25:36 any theoretical framework that says they do.
00:25:37 --> 00:25:39 Uh, they have been suggested by some very
00:25:39 --> 00:25:42 eminent people, but we really don't have any
00:25:42 --> 00:25:44 more than suggestions. People have looked for
00:25:44 --> 00:25:47 evidence for other universes in the cosmic
00:25:47 --> 00:25:48 microwave background radiation that we're
00:25:48 --> 00:25:51 talking about a few minutes ago. Um, but
00:25:51 --> 00:25:54 unless you have an eye of faith, which one or
00:25:54 --> 00:25:56 two people do, there's not really anything
00:25:56 --> 00:25:59 there, nothing to see there. So um,
00:25:59 --> 00:26:01 other universes may well not exist and even
00:26:01 --> 00:26:04 if they do they might end up having the same
00:26:04 --> 00:26:06 speed of light. We simply do not know. But I
00:26:06 --> 00:26:09 think the main problem is going to be getting
00:26:10 --> 00:26:13 from ours into another one. Uh because the
00:26:13 --> 00:26:15 word universe means everything we can see and
00:26:15 --> 00:26:18 observe or deal with. Uh,
00:26:18 --> 00:26:21 and you know, um, transferring
00:26:21 --> 00:26:23 from this universe into another one I
00:26:23 --> 00:26:26 suspect is one that would, with
00:26:26 --> 00:26:28 even with the most open minded science
00:26:28 --> 00:26:31 fiction uh, brain in the world,
00:26:32 --> 00:26:35 um, might cause problems. Uh, unless
00:26:35 --> 00:26:37 you're Martin. Martin will cheerfully write
00:26:37 --> 00:26:39 about it and um, I hope it's a bestseller.
00:26:40 --> 00:26:42 Andrew Dunkley: I don't doubt it.
00:26:42 --> 00:26:43 Professor Fred Watson: Um, I've read a bit of uh,
00:26:43 --> 00:26:46 Andrew Dunkley: Martin's work and I've thoroughly enjoyed it.
00:26:46 --> 00:26:49 So uh, yeah, I would encourage to
00:26:49 --> 00:26:51 look up his books. Um, there's a few
00:26:51 --> 00:26:54 goodies there. Um, yeah.
00:26:55 --> 00:26:57 The speed of light intrigues me because
00:26:58 --> 00:27:01 we know what it is, we know how fast it is,
00:27:01 --> 00:27:03 what 300 kilometres per second or,
00:27:03 --> 00:27:06 or whatever. Um, and
00:27:07 --> 00:27:10 we can't even think about
00:27:10 --> 00:27:12 going near that speed. I mean we can't even
00:27:12 --> 00:27:15 achieve what, 2% of the um,
00:27:16 --> 00:27:17 relativistic speed.
00:27:18 --> 00:27:20 Uh, and if we could that'd be a major
00:27:20 --> 00:27:23 achievement. But um, it's,
00:27:23 --> 00:27:25 it's, it's an uh,
00:27:25 --> 00:27:28 unfathomable number in the scheme of
00:27:28 --> 00:27:28 things.
00:27:28 --> 00:27:31 Professor Fred Watson: Fred Watson. It is. Um, and you
00:27:31 --> 00:27:34 know the very good reasons for believing that
00:27:34 --> 00:27:36 nothing can go faster than that. And that's
00:27:36 --> 00:27:39 because as you accelerate things,
00:27:39 --> 00:27:41 any object with mass, as you accelerate it,
00:27:42 --> 00:27:45 uh, uh, the more
00:27:45 --> 00:27:47 energy it takes. So uh, you know, every
00:27:48 --> 00:27:51 metre per second per second that you add
00:27:51 --> 00:27:53 to its velocity, um, you
00:27:54 --> 00:27:57 kind of have huge energy penalties and
00:27:57 --> 00:28:00 eventually in order it all sort of um,
00:28:00 --> 00:28:02 basically asymptotes to infinity.
00:28:03 --> 00:28:05 In other words you'd have to put infinite
00:28:05 --> 00:28:08 energy into something, uh, to accelerate
00:28:08 --> 00:28:09 something to the speed of light. And we
00:28:09 --> 00:28:11 haven't got infinite energy so we're never
00:28:11 --> 00:28:14 going to do it. Um, there'd be other problems
00:28:14 --> 00:28:17 as well. Uh, so it is a real speed limit.
00:28:17 --> 00:28:20 Uh, it's very sad from the point of view
00:28:20 --> 00:28:22 of science fiction writers or from
00:28:23 --> 00:28:25 scientists. Uh, you've got to find a way of
00:28:25 --> 00:28:27 getting around it. I'm think you're a dab
00:28:27 --> 00:28:29 hand at that. So um, but that's What?
00:28:29 --> 00:28:32 Andrew Dunkley: I can't reveal anything. I'm just in the last
00:28:32 --> 00:28:34 couple of chapters of my trilogy and I'm not.
00:28:34 --> 00:28:36 No, I'm not going to blow the whistle on
00:28:36 --> 00:28:36 myself.
00:28:36 --> 00:28:38 Professor Fred Watson: No, no, don't do that. Don't do that.
00:28:38 --> 00:28:41 Andrew Dunkley: But, yeah, short answer is yes, I've solved
00:28:41 --> 00:28:42 that.
00:28:42 --> 00:28:43 Professor Fred Watson: Yeah, good.
00:28:43 --> 00:28:45 All right, well, I'm glad you have. Um, let
00:28:45 --> 00:28:48 us know what you did to overcome this, uh,
00:28:48 --> 00:28:50 infinite energy requirement.
00:28:51 --> 00:28:53 Andrew Dunkley: Yeah, yeah. Uh, there are ways,
00:28:54 --> 00:28:55 um, in theory,
00:28:55 --> 00:28:58 Professor Fred Watson: but, yes, we haven't figured them out yet.
00:28:58 --> 00:29:00 Andrew Dunkley: Um, so did we answer the question? Oh, yeah,
00:29:00 --> 00:29:01 it was no.
00:29:01 --> 00:29:02 Professor Fred Watson: Yes, it's no.
00:29:02 --> 00:29:04 Andrew Dunkley: Yes, it's no, Martin.
00:29:04 --> 00:29:07 Professor Fred Watson: No, but I do like the
00:29:07 --> 00:29:09 idea. I do like the idea of the Peel Gibb.
00:29:09 --> 00:29:11 The Peel Gib. Yes, yes, that's good.
00:29:11 --> 00:29:14 Andrew Dunkley: Very interesting, Martin.
00:29:14 --> 00:29:16 Uh, if you've got questions for us, please go
00:29:16 --> 00:29:18 to our website and send them in
00:29:18 --> 00:29:20 spacenatspodcast.com SpaceNats
00:29:21 --> 00:29:23 are our two URLs. Uh,
00:29:23 --> 00:29:26 we're working on a third URL. It's
00:29:26 --> 00:29:29 peelgib.com. no, probably, um,
00:29:30 --> 00:29:32 not. But, uh, yeah, you can click on the AMA
00:29:32 --> 00:29:34 tab to send us questions. Don't forget to
00:29:34 --> 00:29:36 tell us who you are or where you're from. You
00:29:36 --> 00:29:38 can do that in, uh, audio or text
00:29:38 --> 00:29:40 format and have a look around while you're
00:29:40 --> 00:29:43 there. Don't forget, too, if you will, to
00:29:43 --> 00:29:45 leave reviews, uh, on whatever
00:29:45 --> 00:29:48 podcasting platform you listen to us through
00:29:48 --> 00:29:50 or via or on.
00:29:50 --> 00:29:52 Um, reviews are very, very helpful,
00:29:52 --> 00:29:55 apparently. They, um, they tell people things
00:29:55 --> 00:29:58 about us that we might not want them to know.
00:29:58 --> 00:30:00 But anyway, uh, you, if you would do
00:30:01 --> 00:30:03 us that, ah, kindness, we would be most
00:30:03 --> 00:30:06 appreciative. Uh, and we are just about. We
00:30:06 --> 00:30:07 are done, Fred Watson. Thank you very much.
00:30:07 --> 00:30:10 And you're off for a few weeks because, um,
00:30:10 --> 00:30:12 you've got, you've got some travelling to do
00:30:12 --> 00:30:14 and some people to see and some bills to pay
00:30:14 --> 00:30:16 and, and all that kind of stuff.
00:30:17 --> 00:30:20 Professor Fred Watson: Yes, it's the travel that's taking me away.
00:30:20 --> 00:30:22 Uh, but I'm, um, delighted that you will be
00:30:22 --> 00:30:25 able to keep the flag, uh, waving and keep
00:30:25 --> 00:30:27 the show on the road with our good friend
00:30:27 --> 00:30:28 John T. Horner.
00:30:28 --> 00:30:30 Andrew Dunkley: Yes, John T. Will be joining us from the
00:30:30 --> 00:30:32 University of Southern Queensland, uh, for a
00:30:32 --> 00:30:34 few weeks. Um, Fred Watson, thank you so
00:30:34 --> 00:30:37 much. Uh, happy trails. Um, and, uh, to you
00:30:37 --> 00:30:38 and Marnie. Have a good trip and we'll see
00:30:38 --> 00:30:39 you when you get back.
00:30:40 --> 00:30:42 Professor Fred Watson: Sounds great. Many thanks, Andrew, and talk
00:30:42 --> 00:30:43 to you soon indeed.
00:30:43 --> 00:30:45 Andrew Dunkley: Professor, uh, Fred Watson Watson, astronomer
00:30:45 --> 00:30:48 at large, part of the team here at Space
00:30:48 --> 00:30:50 Nuts, and thanks to Huw in the studio,
00:30:51 --> 00:30:53 uh, who couldn't be with us today. He tried
00:30:53 --> 00:30:55 to peel a gib and nearly cut his finger off.
00:30:55 --> 00:30:58 And from me, Andrew Dunkley, thanks to your
00:30:58 --> 00:30:59 company, we'll see you on the next episode of
00:30:59 --> 00:31:01 Space Nuts. Bye. Bye.
00:31:02 --> 00:31:04 You've been listening to the Space Nuts
00:31:04 --> 00:31:07 podcast, available at
00:31:07 --> 00:31:09 Apple Podcast, Spotify,
00:31:10 --> 00:31:12 iHeartRadio or your favourite podcast
00:31:12 --> 00:31:14 player. You can also stream on
00:31:14 --> 00:31:17 demand@bytes.um.com. this has been another
00:31:17 --> 00:31:19 quality podcast production from
00:31:19 --> 00:31:20 bytes.um.com.