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In this engaging Q&A episode of Space Nuts, join Andrew Dunkley and Professor Fred Watson as they tackle a variety of intriguing questions from listeners. From the mysteries of redshift and the perplexing concept of dark photons to the vastness of deep space astronomy and the ongoing expansion of the universe, this episode is brimming with thought-provoking insights and scientific discussion.
In this episode:
- Understanding redshift: What does it mean for the energy of light from distant galaxies, and how does it relate to the universe's expansion?
- A deep dive into dark photons: What are they, and how might they help explain dark matter and dark energy?
- Clarifying deep space astronomy: Why do we observe light from distant galaxies as it was billions of years ago, and how does this relate to our understanding of cosmic history?
- Exploring the universe's expansion: What is it expanding into, and what shapes might it take?
- The implications of cosmic observations for our understanding of the universe's structure and evolution.
Resources & Links:
- [NASA's Cosmic Microwave Background](https://map.gsfc.nasa.gov/universe/uni_cmb.html) - Understanding the remnants of the Big Bang.
- [Large Hadron Collider](https://home.cern) - The world's largest particle physics laboratory.
- [Dark Matter and Dark Energy Overview](https://www.nasa.gov/feature/dark-energy-and-dark-matter) - Insights from NASA on these enigmatic components of the universe.
Join Andrew and Fred Watson as they navigate the complexities of space science, encouraging curiosity and exploration of the cosmos. Don't forget to send in your questions for future episodes!
Become a supporter of this podcast: https://www.spreaker.com/podcast/space-nuts-astronomy-insights-cosmic-discoveries--2631155/support.
(00:00) This is a Q and A edition of Space Nuts
(01:14) Question from Roger: Does red shift of galaxies contribute to universe expansion
(07:53) Roger Stern: Well, generally speaking, you do get alternative views on this
(08:33) Fred Watson uses term dark photon to describe hypothetical dark particles
(13:29) Fred: I still can't get my head around deep space astronomy
(22:03) If the universe is expanding, what is it expanding into
(28:08) If you have questions for Space Nuts, please send them via email
00:00:00 --> 00:00:02 Andrew Dunkley: Hello again. Thanks for joining us on Space
00:00:02 --> 00:00:04 Nuts. This is a Q and A edition. My name is
00:00:04 --> 00:00:06 Andrew Dunkley. What's a Q and A edition?
00:00:06 --> 00:00:09 It's an edition where we get Q's and
00:00:09 --> 00:00:12 give you A's because you're so clever.
00:00:12 --> 00:00:14 Uh, something like that. Anyway, we're going
00:00:14 --> 00:00:16 to answer audience questions. That's what I'm
00:00:16 --> 00:00:17 getting at. We've got questions about
00:00:17 --> 00:00:20 redshift, We've got questions about dark
00:00:20 --> 00:00:20 photons.
00:00:20 --> 00:00:21 Professor Fred Watson: What?
00:00:21 --> 00:00:24 Andrew Dunkley: Uh, we've got questions about deep space
00:00:24 --> 00:00:26 astronomy and another one about the expansion
00:00:26 --> 00:00:29 of the universe. I think we talked about that
00:00:29 --> 00:00:31 last episode. Anyway, uh, we'll see if we can
00:00:31 --> 00:00:33 solve all of that on this episode of space
00:00:33 --> 00:00:35 nuts. 15 seconds.
00:00:35 --> 00:00:38 Professor Fred Watson: Guidance is internal. 10,
00:00:38 --> 00:00:41 9, ignition sequence. Star
00:00:41 --> 00:00:41 space nuts.
00:00:41 --> 00:00:43 Andrew Dunkley: 5, 4, 3, 2.
00:00:43 --> 00:00:43 Roger: 1.
00:00:43 --> 00:00:46 Professor Fred Watson: 2, 3, 4, 5, 5, 4, 3, 2,
00:00:46 --> 00:00:48 1. Space nuts.
00:00:48 --> 00:00:50 Andrew Dunkley: Astronauts report it feels good.
00:00:51 --> 00:00:54 And with us again to kind of
00:00:54 --> 00:00:56 try to maybe answer some of that is
00:00:56 --> 00:00:58 Professor Fred Watson Watson, astronomer at
00:00:58 --> 00:00:59 large. Hello, Fred Watson.
00:01:00 --> 00:01:02 Professor Fred Watson: Hello, Andrew. Um, kind of is probably the
00:01:02 --> 00:01:04 best description really, isn't it?
00:01:05 --> 00:01:08 Andrew Dunkley: Possibly so. Possibly so. Um,
00:01:08 --> 00:01:10 but you know, it's good to get questions.
00:01:10 --> 00:01:13 We've got a whole new batch, so, um, let's
00:01:13 --> 00:01:14 get stuck straight into it.
00:01:14 --> 00:01:17 Now. First question comes from, um. Uh,
00:01:18 --> 00:01:20 I love the way he always ends his questions.
00:01:20 --> 00:01:23 I'm not going to reveal anything, but, um,
00:01:23 --> 00:01:24 let's hear from Roger.
00:01:24 --> 00:01:27 Roger: Hey there, Space Nuts. This is Roger
00:01:27 --> 00:01:30 the truck driver. Tonight I'm in,
00:01:30 --> 00:01:33 uh, Rutland, Vermont. Got a
00:01:33 --> 00:01:35 question about the red shift of galaxies.
00:01:36 --> 00:01:38 Um, if the light that we're seeing from a far
00:01:38 --> 00:01:41 off galaxy is shifted to the red and it
00:01:41 --> 00:01:43 started out at a higher frequency,
00:01:44 --> 00:01:46 doesn't that mean energy's lost somewhere
00:01:46 --> 00:01:49 between here and there? And is that energy
00:01:49 --> 00:01:52 just transferred into space? And if it
00:01:52 --> 00:01:55 is, does that contribute to the
00:01:55 --> 00:01:57 expansion of space? And I'm not saying it's
00:01:57 --> 00:01:59 dark energy, but does it
00:01:59 --> 00:02:02 contribute to it or does that
00:02:02 --> 00:02:05 energy get dissipated in another way?
00:02:06 --> 00:02:08 All right. Always digging the show, guys.
00:02:08 --> 00:02:09 Keep on trucking.
00:02:11 --> 00:02:14 Andrew Dunkley: I love that. I love that. Uh, we've got
00:02:14 --> 00:02:15 train drivers that do that. Unfortunately,
00:02:15 --> 00:02:17 they do it at 3 o' clock in the morning.
00:02:18 --> 00:02:21 Although today he did it at 10 to 7. I was
00:02:21 --> 00:02:23 pretty annoyed. Pretty annoyed.
00:02:23 --> 00:02:25 Professor Fred Watson: This is, uh, the one going past your place?
00:02:25 --> 00:02:27 Andrew Dunkley: Yeah, behind our place there's a rail line.
00:02:27 --> 00:02:29 It doesn't get used a heck of a lot, but when
00:02:29 --> 00:02:30 it does, um.
00:02:30 --> 00:02:30 Eli: Yes?
00:02:31 --> 00:02:33 Andrew Dunkley: The glasses rattle. Uh, the ones on my face,
00:02:33 --> 00:02:36 I mean. Uh, thanks, Roger. Great question.
00:02:36 --> 00:02:39 Uh, so, um, yeah, the change
00:02:39 --> 00:02:42 in frequency with the, um,
00:02:43 --> 00:02:46 energy loss, um, where does the energy go and
00:02:46 --> 00:02:48 does it contribute to the expansion of the
00:02:48 --> 00:02:51 universe? And could it possibly be.
00:02:51 --> 00:02:53 Maybe, maybe not dark matter
00:02:54 --> 00:02:56 or dark energy or something?
00:02:56 --> 00:02:58 Professor Fred Watson: Yeah, yeah. Um, there's a lot.
00:02:58 --> 00:02:59 Andrew Dunkley: He packed a lot into that question.
00:03:00 --> 00:03:02 Professor Fred Watson: He did. And it's a great question too. Uh,
00:03:02 --> 00:03:04 and, you know, I mean, it's a,
00:03:04 --> 00:03:07 uh, project, um, Absolutely right. The
00:03:07 --> 00:03:10 conservation of energy. Uh, energy
00:03:10 --> 00:03:12 can't be created or destroyed. That's the
00:03:12 --> 00:03:15 fundamental rule. Its
00:03:15 --> 00:03:17 energy is always conserved.
00:03:18 --> 00:03:21 But, uh, the universe doesn't play
00:03:21 --> 00:03:23 by the ordinary rules.
00:03:24 --> 00:03:26 Uh, and, um,
00:03:28 --> 00:03:31 it's an interesting answer here.
00:03:31 --> 00:03:34 Um, and I have to say it's changed
00:03:34 --> 00:03:37 my view of what this, you know, what
00:03:37 --> 00:03:40 the answer to this problem was because,
00:03:40 --> 00:03:43 um, when we've been asked this before,
00:03:43 --> 00:03:45 we haven't been asked it for a long time.
00:03:46 --> 00:03:48 I just assumed that the energy, uh,
00:03:49 --> 00:03:51 basically was absorbed by the universe by
00:03:51 --> 00:03:54 space time, uh, and
00:03:55 --> 00:03:57 maybe contributed to the expansion.
00:03:57 --> 00:03:58 Although,
00:04:00 --> 00:04:02 uh, you can't have it both ways because it's
00:04:02 --> 00:04:05 the expansion that's causing the photon's
00:04:05 --> 00:04:08 energy to be lost. Uh,
00:04:08 --> 00:04:11 and just stepping back, exactly as
00:04:11 --> 00:04:13 Roger said, uh, you've got light going
00:04:13 --> 00:04:15 through the universe. It's,
00:04:15 --> 00:04:18 uh, its wavelength is being stretched by
00:04:18 --> 00:04:21 the expansion of the universe. Therefore the
00:04:21 --> 00:04:24 light is losing energy. Because the energy
00:04:24 --> 00:04:26 of a beam of light is all about the
00:04:26 --> 00:04:28 frequency of the light, in other words, or
00:04:28 --> 00:04:31 the wavelength. Putting it another way. So
00:04:31 --> 00:04:34 if you increase the wavelength, you lose
00:04:34 --> 00:04:37 energy. And that's, um,
00:04:37 --> 00:04:40 a given already. Uh, so what I
00:04:40 --> 00:04:42 used to say was, yes, it kind of goes into
00:04:42 --> 00:04:44 the universe. But I've done a bit more
00:04:44 --> 00:04:46 reading on this and I was wrong.
00:04:48 --> 00:04:51 Um, because when
00:04:51 --> 00:04:54 you apply general relativity to
00:04:54 --> 00:04:56 the universe as a whole, and that's the.
00:04:57 --> 00:04:59 As we've talked about, and we've talked about
00:04:59 --> 00:05:01 it at length in the last episode, it's, uh,
00:05:01 --> 00:05:04 the kind of fundamental rule that governs
00:05:04 --> 00:05:06 everything that we understand in the
00:05:06 --> 00:05:09 universe. Um, when you
00:05:09 --> 00:05:11 apply general relativity,
00:05:12 --> 00:05:12 Andrew Dunkley: uh,
00:05:12 --> 00:05:15 Professor Fred Watson: that conservation of energy
00:05:16 --> 00:05:19 that we expect to happen in the
00:05:19 --> 00:05:22 everyday world, it
00:05:22 --> 00:05:24 doesn't hold good. So energy, uh,
00:05:25 --> 00:05:27 is not conserved in an expanding
00:05:27 --> 00:05:30 universe. Uh, and so
00:05:31 --> 00:05:33 basically the energy
00:05:33 --> 00:05:36 simply disappears. It's
00:05:36 --> 00:05:39 just not there anymore because of the
00:05:39 --> 00:05:41 expansion of the universe. It's not causing
00:05:41 --> 00:05:43 the expansion of the universe. It's not
00:05:43 --> 00:05:45 create contributing to dark energy or dark
00:05:45 --> 00:05:48 matter, the energy loss, it just vanishes.
00:05:49 --> 00:05:51 Wow. So work that one out.
00:05:51 --> 00:05:52 Andrew Dunkley: I can't.
00:05:53 --> 00:05:54 Professor Fred Watson: No, I can't either.
00:05:56 --> 00:05:59 Um, I kind of really
00:05:59 --> 00:06:01 need to look at the equations on this.
00:06:02 --> 00:06:04 Andrew Dunkley: Um, don't show them to me. I mean,
00:06:06 --> 00:06:08 Professor Fred Watson: yeah, I'M not that keen on looking at them
00:06:08 --> 00:06:10 myself either. Too much else to do. But, uh,
00:06:11 --> 00:06:14 um, uh, but yes, that is
00:06:14 --> 00:06:16 the thinking on this.
00:06:17 --> 00:06:19 Uh, and I think the conservation
00:06:19 --> 00:06:22 rule does not work, uh,
00:06:24 --> 00:06:26 um, when it comes to
00:06:28 --> 00:06:29 the universe on a whole.
00:06:30 --> 00:06:30 Andrew Dunkley: Yeah.
00:06:30 --> 00:06:30 Professor Fred Watson: Wow.
00:06:30 --> 00:06:33 Andrew Dunkley: Gee, um, that's quite a
00:06:33 --> 00:06:35 revelation. Who figured that out?
00:06:37 --> 00:06:39 Professor Fred Watson: Uh, uh, it's on a number of
00:06:40 --> 00:06:43 different, uh, physics, uh, related websites.
00:06:43 --> 00:06:45 Andrew Dunkley: There's the reason no one knows about it
00:06:45 --> 00:06:47 because it's physics and
00:06:48 --> 00:06:50 who reads that stuff?
00:06:50 --> 00:06:53 Professor Fred Watson: Yeah, I think the relativistic bit of
00:06:53 --> 00:06:56 it, uh, comes from the fact
00:06:57 --> 00:07:00 that the energy of a particle,
00:07:00 --> 00:07:02 which is what we're talking about, it's an
00:07:02 --> 00:07:04 observer dependent quantity.
00:07:05 --> 00:07:08 And so that's why relativity plays a part in
00:07:08 --> 00:07:10 this because you're the observer
00:07:11 --> 00:07:13 and you're talking about something that's
00:07:13 --> 00:07:15 relative to another observer, that is the
00:07:15 --> 00:07:18 photon. Uh, and that's why you've got,
00:07:18 --> 00:07:21 uh, a relativistic
00:07:22 --> 00:07:23 access. Ah, to it.
00:07:24 --> 00:07:26 Andrew Dunkley: Wow. Okay. Um, great question,
00:07:26 --> 00:07:29 Roger. I'm not sure you were expecting that
00:07:29 --> 00:07:31 answer, but, uh, there it is. Uh, the energy
00:07:31 --> 00:07:34 just gone,
00:07:35 --> 00:07:38 goes, vanishes, ceases to
00:07:38 --> 00:07:40 exist. It's a dead poly.
00:07:41 --> 00:07:44 So anyway, um,
00:07:45 --> 00:07:47 no one got that joke. I was, um,
00:07:48 --> 00:07:50 doing a Monty Python skit for some reason.
00:07:50 --> 00:07:52 Professor Fred Watson: Yeah, you were. That's right.
00:07:53 --> 00:07:55 Look, I'm pursuing this in a little bit more
00:07:55 --> 00:07:58 detail and, uh, just trying to, you know, see
00:07:58 --> 00:08:00 whether we've got alternative. Alternative
00:08:00 --> 00:08:02 views of this.
00:08:02 --> 00:08:04 Andrew Dunkley: Well, generally speaking, you do get
00:08:04 --> 00:08:06 alternative views when it comes to this kind
00:08:06 --> 00:08:06 of stuff.
00:08:06 --> 00:08:09 Professor Fred Watson: That's right. Um, yes,
00:08:09 --> 00:08:10 so
00:08:12 --> 00:08:15 that's right. Uh, uh,
00:08:15 --> 00:08:18 I think the standard explanation today is
00:08:18 --> 00:08:21 that energy is not conserved.
00:08:21 --> 00:08:22 Okay.
00:08:23 --> 00:08:24 Andrew Dunkley: We'll leave it at that until somebody throws
00:08:24 --> 00:08:26 another spanner into the.
00:08:26 --> 00:08:27 Professor Fred Watson: Yeah, uh, we might be giving a different
00:08:27 --> 00:08:29 answer next week. It could be.
00:08:29 --> 00:08:31 Andrew Dunkley: Thanks, Roger. Great to hear from you. Toot,
00:08:31 --> 00:08:33 toot. Uh, we'll catch you next time.
00:08:33 --> 00:08:36 Our next question comes from
00:08:36 --> 00:08:39 Peter. He's from San Diego, California.
00:08:39 --> 00:08:40 While listening to another astrophysics
00:08:41 --> 00:08:43 podcast, I heard the term dark
00:08:43 --> 00:08:46 photon for the first time. Apparently this is
00:08:46 --> 00:08:48 a particle astrophysicists are, uh, seeking
00:08:49 --> 00:08:51 in order to explain dark matter and, or dark
00:08:51 --> 00:08:54 energy. Could you please elaborate on what a
00:08:54 --> 00:08:56 dark photon could be?
00:08:57 --> 00:08:59 Um, dad, joke for Andrew. A photon
00:08:59 --> 00:09:02 travels at the speed of light. Does that mean
00:09:02 --> 00:09:04 a dark photon travels at the speed of
00:09:04 --> 00:09:07 dark. I like that.
00:09:07 --> 00:09:09 That's good. Yeah, that's really good. Uh,
00:09:09 --> 00:09:12 keep up the great work, he says. Uh, thank
00:09:12 --> 00:09:12 you, Peter.
00:09:13 --> 00:09:13 Professor Fred Watson: All as well.
00:09:13 --> 00:09:15 Andrew Dunkley: In San Diego, California.
00:09:16 --> 00:09:18 Uh, have you ever heard of a dark photon,
00:09:18 --> 00:09:18 Fred Watson?
00:09:19 --> 00:09:21 Professor Fred Watson: Um, yes, I'VE probably got a few in this box
00:09:21 --> 00:09:24 here. The
00:09:24 --> 00:09:26 speed of dark. Just, just going back to that,
00:09:26 --> 00:09:29 that quip, uh, there was
00:09:29 --> 00:09:32 a storey I read, uh, probably
00:09:32 --> 00:09:35 a fortnight ago, uh, about
00:09:36 --> 00:09:38 exactly this. In that dark
00:09:39 --> 00:09:42 ness can move faster than the speed
00:09:42 --> 00:09:42 of light.
00:09:43 --> 00:09:43 Andrew Dunkley: No,
00:09:46 --> 00:09:49 Professor Fred Watson: but it's ah, an illusory darkness. It's when
00:09:49 --> 00:09:52 you've got um, light beams
00:09:52 --> 00:09:55 interfering with one another so that
00:09:55 --> 00:09:57 you've uh, interference
00:09:58 --> 00:10:00 light beams can cancel out. So if you've got
00:10:00 --> 00:10:03 two light waves and you add them up out of
00:10:03 --> 00:10:04 phase, they can cancel out and you get
00:10:04 --> 00:10:07 darkness. That's a well known principle
00:10:07 --> 00:10:09 of interferometry. I used to play with that
00:10:09 --> 00:10:12 when I was a student a lot. Uh,
00:10:12 --> 00:10:14 but there are certain circumstances that
00:10:14 --> 00:10:17 those patterns of darkness can actually
00:10:17 --> 00:10:19 exceed the speed of light
00:10:20 --> 00:10:22 because they're not actually real, they're
00:10:22 --> 00:10:24 not real entities. They're not a thing that's
00:10:24 --> 00:10:26 carrying any sort of information or energy.
00:10:26 --> 00:10:29 They're just patterns in an
00:10:29 --> 00:10:31 interference pattern. They're just dark
00:10:31 --> 00:10:32 patches in it. And I think under certain
00:10:32 --> 00:10:35 circumstances they could go faster than the
00:10:35 --> 00:10:38 speed of light. Darkness might
00:10:38 --> 00:10:41 be not quite as uh, you know, as twee as
00:10:41 --> 00:10:43 you thought it was. I guess so
00:10:43 --> 00:10:46 anyway, anyway, uh, that's not the
00:10:47 --> 00:10:49 question, uh, because dark photons are
00:10:49 --> 00:10:52 definitely something different and they're
00:10:52 --> 00:10:55 basically uh, hypothetical.
00:10:55 --> 00:10:58 They've been hypothesised by
00:10:58 --> 00:11:01 physicists and cosmologists as uh,
00:11:01 --> 00:11:03 being a uh, force carrier
00:11:04 --> 00:11:06 similar to the ordinary photon
00:11:07 --> 00:11:10 but related to dark
00:11:10 --> 00:11:13 matter. In other
00:11:13 --> 00:11:15 words, you might have. Sorry, somebody's
00:11:15 --> 00:11:17 trying to phone me. I'm just gonna kill that
00:11:17 --> 00:11:20 call. Yeah, um,
00:11:21 --> 00:11:21 that was me.
00:11:21 --> 00:11:23 Andrew Dunkley: That was me. No it wasn't.
00:11:26 --> 00:11:29 Professor Fred Watson: You know, they're part of the. There may be.
00:11:29 --> 00:11:32 When we discover finally what dark matter is,
00:11:33 --> 00:11:35 there may be a suite of
00:11:36 --> 00:11:39 dark particles which could include
00:11:39 --> 00:11:41 dark photons. That's the bottom line.
00:11:41 --> 00:11:42 Andrew Dunkley: Right?
00:11:42 --> 00:11:45 Professor Fred Watson: Um, and so you know we mentioned last
00:11:45 --> 00:11:48 week the, or in the last episode the uh, the
00:11:48 --> 00:11:50 Large Hadron Collider being upgraded to the
00:11:50 --> 00:11:53 High Luminosity Large Hadron Collider. Um,
00:11:53 --> 00:11:56 that's one of the things they'd be looking
00:11:56 --> 00:11:57 for, will be dark photons.
00:11:58 --> 00:11:59 Okay.
00:11:59 --> 00:12:02 Andrew Dunkley: You know, I tried to do
00:12:02 --> 00:12:04 um, an AI search for an
00:12:04 --> 00:12:06 explanation on it and um,
00:12:07 --> 00:12:10 it sort of gave me all this gobbledygook. But
00:12:10 --> 00:12:12 um, you know, what would a dark
00:12:12 --> 00:12:15 proton, a photon do? It says it would
00:12:15 --> 00:12:17 carry a force within the dark sector.
00:12:19 --> 00:12:21 We call that the government. It might allow
00:12:21 --> 00:12:23 dark matter particles to interact with each
00:12:23 --> 00:12:25 other and it could very weakly mix with
00:12:25 --> 00:12:28 normal photons, giving us a way to Detect it.
00:12:28 --> 00:12:31 And the reason they reckon that scientists
00:12:31 --> 00:12:34 care about this, as you said, could explain
00:12:34 --> 00:12:36 what dark matter is made of. So
00:12:36 --> 00:12:39 therefore solving some of those gaps in our
00:12:39 --> 00:12:40 current physics theories.
00:12:43 --> 00:12:45 That's why people are interested in this and
00:12:45 --> 00:12:47 that's why they're upgrading the Large Hadron
00:12:47 --> 00:12:50 Collider. And hopefully we will
00:12:50 --> 00:12:52 learn more in years to come.
00:12:54 --> 00:12:55 That's the hope.
00:12:55 --> 00:12:58 Professor Fred Watson: That's the hope, yeah. So we might be talking
00:12:58 --> 00:13:01 one day about dark photons, um, having been
00:13:01 --> 00:13:03 detected, which would be a coup
00:13:03 --> 00:13:05 for space newts.
00:13:05 --> 00:13:08 Andrew Dunkley: Yes, it will. Uh, but at this stage they
00:13:08 --> 00:13:11 are not proven. It's just a theory. So
00:13:11 --> 00:13:13 that's about as much as we know at this point
00:13:13 --> 00:13:16 in time. But, uh, very good question. Uh,
00:13:16 --> 00:13:19 and, uh, thank you, Peter, for sending it in.
00:13:19 --> 00:13:22 This is Space Nuts with Andrew Dunkley and
00:13:22 --> 00:13:23 Professor Fred Watson Watson.
00:13:26 --> 00:13:29 0G and I feel fine. Space Nuts.
00:13:29 --> 00:13:31 Okay, Fred Watson, we'll move straight on to
00:13:31 --> 00:13:33 our next question, which is, uh, another
00:13:33 --> 00:13:36 audio question from Eli.
00:13:36 --> 00:13:39 Eli: Hello, this is Eli from
00:13:39 --> 00:13:42 sunny Coachella Valley in
00:13:42 --> 00:13:45 California. I'm embarrassed to
00:13:45 --> 00:13:47 admit it, but I still can't get my head
00:13:47 --> 00:13:50 around deep space astronomy. I get that
00:13:50 --> 00:13:53 the light from, say, a distant galaxy is a
00:13:53 --> 00:13:56 billion years old, but why
00:13:56 --> 00:13:59 that particular point in its time? Is
00:13:59 --> 00:14:01 it just a matter of whatever light is hitting
00:14:01 --> 00:14:03 us is the time we get to see.
00:14:05 --> 00:14:06 But for really early light,
00:14:07 --> 00:14:10 the JWST, early universe stuff
00:14:10 --> 00:14:13 that's been travelling for 13 billion years
00:14:13 --> 00:14:15 and just hitting us now,
00:14:16 --> 00:14:18 are we looking for the light that hasn't
00:14:19 --> 00:14:21 passed us by or hasn't made it here yet,
00:14:22 --> 00:14:24 but is from that one precise
00:14:24 --> 00:14:25 location long ago?
00:14:27 --> 00:14:30 This stuff is so difficult to get my head
00:14:30 --> 00:14:33 around. Love the show and hope
00:14:33 --> 00:14:34 you guys can clear this up for me.
00:14:36 --> 00:14:38 Andrew Dunkley: Uh, no, we can't. We just thought we'd, um,
00:14:38 --> 00:14:41 put the question in there. Thanks,
00:14:41 --> 00:14:44 Eli. Uh, this is a deep, um, I'm, um.
00:14:44 --> 00:14:46 Not only in deep space astronomy terms, but
00:14:46 --> 00:14:48 it is a deep, deep topic.
00:14:48 --> 00:14:51 Um, I mean, when we look up into the sky
00:14:51 --> 00:14:53 at night and we see all those beautiful
00:14:53 --> 00:14:56 coloured dots, we are looking at history.
00:14:56 --> 00:14:59 And it's variable history because some of
00:14:59 --> 00:15:01 it's 4.41 light years away and
00:15:01 --> 00:15:04 some of it's 400 light
00:15:04 --> 00:15:07 years away, some of it's further than that.
00:15:07 --> 00:15:09 Um, but then you've got the cosmic
00:15:10 --> 00:15:12 microwave background radiation, which is kind
00:15:12 --> 00:15:14 of a leftover of,
00:15:14 --> 00:15:17 um, what happened after the
00:15:17 --> 00:15:19 Big Bang and that,
00:15:20 --> 00:15:23 that's a different kettle of fish. And I can
00:15:23 --> 00:15:25 understand why you've got a headache. Eli,
00:15:25 --> 00:15:26 over to you, Fred Watson.
00:15:27 --> 00:15:30 Professor Fred Watson: Thanks. Um, so I
00:15:30 --> 00:15:32 guess uh, you know,
00:15:33 --> 00:15:36 I understand Eli's issue as well.
00:15:36 --> 00:15:36 Um,
00:15:38 --> 00:15:40 you've got to be in the right place at the
00:15:40 --> 00:15:43 right time to see a photon from a distant
00:15:43 --> 00:15:46 galaxy. But I guess the way
00:15:46 --> 00:15:48 to envisage this is if you think
00:15:48 --> 00:15:50 of the universe, um,
00:15:51 --> 00:15:54 and you've got to perhaps think of it as if
00:15:54 --> 00:15:55 you were looking at it from the outside,
00:15:55 --> 00:15:58 which we never can. But, uh, if you can think
00:15:58 --> 00:16:00 of it that way, then it's full of
00:16:01 --> 00:16:03 objects which are radiating light.
00:16:04 --> 00:16:06 Even in its infancy, when the universe was
00:16:06 --> 00:16:09 very young, the stuff in it was basically
00:16:09 --> 00:16:12 shining. Um, once we got past the Dark Ages,
00:16:12 --> 00:16:14 where no stars were shining, uh,
00:16:15 --> 00:16:18 um, and those are the galaxies that we now
00:16:18 --> 00:16:20 see. So they constantly radiate, creating
00:16:20 --> 00:16:23 light. And that's just like a river of
00:16:23 --> 00:16:26 light that's flowing down time,
00:16:26 --> 00:16:29 if I can put it that way. Uh, and
00:16:30 --> 00:16:33 a long time in the future it
00:16:33 --> 00:16:35 reaches us. But it's not just
00:16:36 --> 00:16:38 an individual photon or something that's
00:16:38 --> 00:16:41 reaching us. It's this stream of stuff that
00:16:41 --> 00:16:43 is being radiated throughout the
00:16:43 --> 00:16:46 universe by these galaxies. So we,
00:16:46 --> 00:16:49 um. And we pick it up. We
00:16:49 --> 00:16:52 pick it up sometimes exactly as you've said.
00:16:52 --> 00:16:54 Well, up to 10 billion years after it's been
00:16:54 --> 00:16:57 radiated. I think 12 billion years,
00:16:58 --> 00:17:00 uh, are the oldest or the earliest galaxies
00:17:00 --> 00:17:02 that we now see. We're looking back in time
00:17:02 --> 00:17:05 12 billion years and seeing them as they were
00:17:05 --> 00:17:08 perhaps a billion and a half years after the
00:17:08 --> 00:17:11 Big Bang. Um, and they are shining,
00:17:11 --> 00:17:13 they're radiating light, uh, in the early
00:17:13 --> 00:17:16 universe and down the track that reaches us
00:17:16 --> 00:17:18 because that light's going in all directions.
00:17:18 --> 00:17:20 So it wouldn't matter where in the universe
00:17:20 --> 00:17:22 we were, we would still see them.
00:17:23 --> 00:17:25 Uh, we'd just see them in a, you know, in a
00:17:25 --> 00:17:27 different position in the sky. If we're a
00:17:27 --> 00:17:30 long way from where we are now. Yeah, but,
00:17:30 --> 00:17:33 yeah, so I guess it's, you
00:17:33 --> 00:17:35 know, in a way, one way of thinking about
00:17:35 --> 00:17:38 this is if you imagine us on planet
00:17:38 --> 00:17:41 Earth here and imagine us being
00:17:41 --> 00:17:44 surrounded by a whole series of
00:17:44 --> 00:17:47 shells which, uh, we're at the centre
00:17:47 --> 00:17:49 of. And this is a bit like the crystalline
00:17:49 --> 00:17:51 spheres that people used to think, uh, the
00:17:51 --> 00:17:54 universe was made of. Uh, but
00:17:54 --> 00:17:57 these shells, uh, spherical shells,
00:17:57 --> 00:17:59 all centred on the Earth, but each one
00:18:00 --> 00:18:02 clicks over to a time
00:18:02 --> 00:18:05 further in the past, uh, because the
00:18:05 --> 00:18:08 light's coming to us from the whole cosmos,
00:18:08 --> 00:18:11 which is full of stuff. Uh, and that's why
00:18:11 --> 00:18:13 we, these shells sort of being
00:18:13 --> 00:18:16 illuminated in a way by the objects that, uh,
00:18:16 --> 00:18:18 radiated them at that time. Uh,
00:18:20 --> 00:18:22 um, that we see them because of
00:18:23 --> 00:18:25 the distance that they are away from us means
00:18:25 --> 00:18:28 that the light has taken that long to get to
00:18:28 --> 00:18:31 us, whether that helps or not. In fact, I
00:18:31 --> 00:18:33 think I've just confused it completely. But,
00:18:35 --> 00:18:36 Andrew Dunkley: um, I
00:18:38 --> 00:18:41 just doing a little experimental search here
00:18:41 --> 00:18:41 for a sec.
00:18:44 --> 00:18:46 What I agree
00:18:46 --> 00:18:49 with in terms of Eli's question and getting
00:18:49 --> 00:18:52 your head around it is, um, if
00:18:52 --> 00:18:54 Betelgeuse, or however you want to pronounce
00:18:54 --> 00:18:57 it, went supernova right now as we
00:18:57 --> 00:18:58 were speaking,
00:19:00 --> 00:19:02 we wouldn't see it for
00:19:03 --> 00:19:05 640 years.
00:19:05 --> 00:19:06 Roger: Yeah.
00:19:07 --> 00:19:09 Andrew Dunkley: So for it to have gone
00:19:09 --> 00:19:12 supernova in the past and us to witness
00:19:12 --> 00:19:14 it, it has to have happened
00:19:15 --> 00:19:18 pretty close to 640 years ago.
00:19:19 --> 00:19:20 Does that make sense?
00:19:20 --> 00:19:23 Professor Fred Watson: Yes. Um, so you could think of that in
00:19:23 --> 00:19:25 another way. Um, you know,
00:19:26 --> 00:19:29 um, anywhere between us and 640
00:19:29 --> 00:19:31 light years away, there could be this pulse
00:19:31 --> 00:19:33 of light that's on its way to us
00:19:34 --> 00:19:37 from Betelgeuse. Uh, it would spread
00:19:37 --> 00:19:39 out in a sphere, and as that sphere
00:19:39 --> 00:19:42 expanded, eventually it would wash over the
00:19:42 --> 00:19:44 Earth and we'd see it, um, and perhaps
00:19:44 --> 00:19:46 see it during the day as well, because it
00:19:46 --> 00:19:49 might get bright enough to do that. Uh, and
00:19:49 --> 00:19:51 I think that's a really good way of putting
00:19:51 --> 00:19:53 it, Andrew, because thinking, um, about the
00:19:53 --> 00:19:55 galaxies, they're just streaming light out
00:19:55 --> 00:19:58 all the time, but something like a, uh,
00:19:58 --> 00:20:01 supernova explosion, which gives a big pulse
00:20:01 --> 00:20:04 of light, um, that's perhaps easier to get
00:20:04 --> 00:20:06 your head around because that's. That's just
00:20:06 --> 00:20:08 gotta, um. It'll
00:20:08 --> 00:20:11 take whatever time is
00:20:11 --> 00:20:14 represented by the distance away. So 640
00:20:14 --> 00:20:17 light years away. It'll take 640 years
00:20:17 --> 00:20:19 to get here for that pulse to get here. But
00:20:19 --> 00:20:22 then it will sweep over us and we'll see the
00:20:22 --> 00:20:24 light. The light fading away.
00:20:24 --> 00:20:25 Andrew Dunkley: Yeah. And, um,
00:20:27 --> 00:20:29 the reason I chose that target is because
00:20:29 --> 00:20:32 there's a lot of conjecture about
00:20:32 --> 00:20:35 its future and the possibility that it's
00:20:35 --> 00:20:36 reaching that critical mass point.
00:20:37 --> 00:20:37 Professor Fred Watson: Yes.
00:20:38 --> 00:20:39 Andrew Dunkley: Um, but it could have already happened.
00:20:39 --> 00:20:41 That's the other thing.
00:20:42 --> 00:20:45 Professor Fred Watson: But that's something we can have no knowledge
00:20:45 --> 00:20:47 of. That's the key thing, because, um,
00:20:47 --> 00:20:50 we are limited by the speed of light. That's
00:20:50 --> 00:20:52 the thing that always limits our view of the
00:20:52 --> 00:20:52 universe.
00:20:52 --> 00:20:55 Andrew Dunkley: And just to confuse Eli a little bit more,
00:20:56 --> 00:20:59 there are, ah, probably things in the
00:20:59 --> 00:21:01 universe we will never witness because the
00:21:01 --> 00:21:04 light is just too far away to reach us in any
00:21:04 --> 00:21:05 reasonable amount of time. Even
00:21:06 --> 00:21:09 beyond the life of the Earth itself or
00:21:09 --> 00:21:12 our sun. Uh,
00:21:13 --> 00:21:15 there are things we will never, ever know
00:21:15 --> 00:21:16 about.
00:21:16 --> 00:21:17 Professor Fred Watson: Correct.
00:21:18 --> 00:21:21 Andrew Dunkley: Um, and that's where it just gives you, um,
00:21:22 --> 00:21:24 one of those Headaches that requires, uh, you
00:21:24 --> 00:21:27 to take paracetamol and ibuprofen at the same
00:21:27 --> 00:21:27 time.
00:21:32 --> 00:21:34 Um, deep, deep headaches. But Eli, great
00:21:34 --> 00:21:36 question. I'm not sure we solved your
00:21:36 --> 00:21:39 problem, but, um, anyway, uh,
00:21:40 --> 00:21:42 I try to explain this sort of stuff to my
00:21:42 --> 00:21:45 grandson, uh, and, uh, my granddaughters.
00:21:45 --> 00:21:48 And, you know, how do you
00:21:48 --> 00:21:50 explain time and distance
00:21:51 --> 00:21:53 to a young child? And, um,
00:21:53 --> 00:21:55 when you're trying to get through traffic,
00:21:57 --> 00:21:58 Professor Fred Watson: that might not be the best time to do it.
00:21:58 --> 00:22:00 Andrew Dunkley: Probably not, but they're very interested.
00:22:01 --> 00:22:03 Very interested. Thanks, Eli.
00:22:03 --> 00:22:03 Great question.
00:22:06 --> 00:22:09 Professor Fred Watson: The crew of Artemis 2 now bound for the moon,
00:22:09 --> 00:22:11 humanity's next great voyage begins.
00:22:12 --> 00:22:13 Space nuts.
00:22:14 --> 00:22:16 Andrew Dunkley: Our final question comes, uh,
00:22:16 --> 00:22:19 from Nova Scotia. It's from Ken.
00:22:19 --> 00:22:21 Uh, look, this is an old chestnut. We've,
00:22:21 --> 00:22:24 we've probably spoken about this many times,
00:22:24 --> 00:22:27 but it's always good to, um, to revisit. If
00:22:27 --> 00:22:30 the universe is expanding, what is it
00:22:30 --> 00:22:32 expanding into? And also,
00:22:33 --> 00:22:35 is the universe spherical?
00:22:36 --> 00:22:39 Professor Fred Watson: So, um, yes. What's it expanding into?
00:22:39 --> 00:22:41 Andrew Dunkley: Well, we don't know.
00:22:41 --> 00:22:43 Professor Fred Watson: And yes, that's.
00:22:43 --> 00:22:45 Yes. Uh, it's actually, we don't know. And
00:22:45 --> 00:22:48 maybe, maybe, maybe. So,
00:22:49 --> 00:22:51 um, the universe
00:22:52 --> 00:22:55 is everything that we can detect. That's
00:22:55 --> 00:22:56 the definition of the universe. Everything we
00:22:56 --> 00:22:59 can measure or detect. And that means,
00:23:00 --> 00:23:02 and we observe the expansion,
00:23:03 --> 00:23:06 but we don't know whether there's an edge
00:23:06 --> 00:23:08 to the universe. We don't know whether it's
00:23:08 --> 00:23:10 infinite. We don't know anything beyond the
00:23:10 --> 00:23:13 horizons that we see. And um, the most
00:23:13 --> 00:23:14 obvious one is the cosmic microwave
00:23:14 --> 00:23:16 background radiation, um,
00:23:17 --> 00:23:19 beyond which we can't see. But the universe
00:23:19 --> 00:23:21 almost certainly goes on beyond that,
00:23:22 --> 00:23:24 probably for a very long way, maybe very big.
00:23:24 --> 00:23:27 But we've got no knowledge of a boundary or
00:23:28 --> 00:23:30 any other medium that it might be expanding
00:23:30 --> 00:23:33 into. So, um,
00:23:33 --> 00:23:36 uh, one possibility is the idea of multiple
00:23:36 --> 00:23:38 universes. And they might
00:23:38 --> 00:23:40 exist maybe
00:23:41 --> 00:23:44 in a higher dimensional, uh,
00:23:45 --> 00:23:48 arena, if I can put it that way. You know,
00:23:48 --> 00:23:51 if you can, um, find that
00:23:51 --> 00:23:54 there are extra dimensions, we know the
00:23:54 --> 00:23:56 three dimensions of space and one of time.
00:23:56 --> 00:23:58 That's what we've got now.
00:23:59 --> 00:24:02 But, uh, if there are hidden
00:24:02 --> 00:24:04 extra dimensions, maybe they provide
00:24:05 --> 00:24:08 a venue for the universe to expand into.
00:24:08 --> 00:24:11 Uh, and there are various theories
00:24:11 --> 00:24:14 that accept that, um, M. M theory is one of
00:24:14 --> 00:24:17 them, where M is probably an abbreviation
00:24:17 --> 00:24:19 for membrane. The idea is that the universe
00:24:20 --> 00:24:22 can be collapsed onto a two dimensional
00:24:22 --> 00:24:24 membrane, and there are lots of these
00:24:24 --> 00:24:27 membranes in the kind
00:24:27 --> 00:24:29 of higher dimensional universe. But that's
00:24:29 --> 00:24:31 just conjecture and we've got no
00:24:32 --> 00:24:34 mechanism for proving that at the moment. The
00:24:34 --> 00:24:36 only thing we know with certainty with
00:24:36 --> 00:24:38 absolute certainty is that the universe is
00:24:38 --> 00:24:39 expanding.
00:24:39 --> 00:24:41 Andrew Dunkley: Yes. Uh, at an accelerating rate. Although
00:24:41 --> 00:24:43 the accelerating rate's not as accelerating
00:24:43 --> 00:24:45 as it once was. Possibly.
00:24:45 --> 00:24:46 Professor Fred Watson: Possibly.
00:24:46 --> 00:24:49 Andrew Dunkley: Um, yeah. There's three possible
00:24:49 --> 00:24:52 shapes of the universe. He asks if it's
00:24:52 --> 00:24:55 a sphere. Um, there's, uh, the flat
00:24:55 --> 00:24:58 universe theory. Do we have to go there? Uh,
00:24:58 --> 00:25:00 there's the closed universe
00:25:01 --> 00:25:04 theory, which is the positive curvature, so a
00:25:04 --> 00:25:06 sphere. Or the open universe theory,
00:25:06 --> 00:25:09 which is negative curvature. Huh. So it's
00:25:09 --> 00:25:11 more like the shape of a saddle. From what
00:25:11 --> 00:25:13 I'm reading, the most popular,
00:25:15 --> 00:25:17 uh, likelihood is the flat universe theory.
00:25:18 --> 00:25:21 Professor Fred Watson: But it's only flat in a Euclidean sense.
00:25:21 --> 00:25:23 It doesn't mean it's shaped like a
00:25:23 --> 00:25:26 tabletop. Uh, it means that parallel
00:25:26 --> 00:25:29 lines never meet. Basically, that's what we
00:25:29 --> 00:25:31 mean by flat. It's the shape of the geometry.
00:25:32 --> 00:25:35 Andrew Dunkley: And the other thing that they suggest is
00:25:35 --> 00:25:37 that, um, it can be flat and still
00:25:37 --> 00:25:39 expanding. As you said, uh, it might be
00:25:39 --> 00:25:42 infinite. We've talked about that before.
00:25:42 --> 00:25:45 And there is likely no centre and no edge.
00:25:46 --> 00:25:48 Professor Fred Watson: Correct. That's what we believe
00:25:49 --> 00:25:51 now, um, to its shape.
00:25:52 --> 00:25:54 So, uh, so
00:25:56 --> 00:25:58 basically, I think Ken's question is, is it
00:25:58 --> 00:26:00 spherical? And
00:26:01 --> 00:26:03 we don't know the answer to that. We know
00:26:03 --> 00:26:06 that the volume within which we can
00:26:06 --> 00:26:08 detect is spherical because
00:26:09 --> 00:26:12 the cosmic microwave background radiation
00:26:12 --> 00:26:15 forms an imaginary shell,
00:26:16 --> 00:26:19 uh, all around our galaxy. And it's
00:26:19 --> 00:26:21 the same distance in every direction. So in
00:26:21 --> 00:26:24 that regard, it's what we call isotropic, the
00:26:24 --> 00:26:26 same in all directions. Uh, and
00:26:26 --> 00:26:28 that's really the only thing we can
00:26:29 --> 00:26:32 lay it down to. But there are ideas that if
00:26:32 --> 00:26:34 you looked at the universe on a bigger scale
00:26:34 --> 00:26:36 than we could see, it wouldn't be. That it
00:26:36 --> 00:26:38 might be different in different directions.
00:26:39 --> 00:26:42 Um, and that, in fact, has been
00:26:42 --> 00:26:44 hypothesised as one of the sources of dark
00:26:44 --> 00:26:47 energy, that we're just seeing a local bit of
00:26:47 --> 00:26:49 the universe that's expanding, whose, uh,
00:26:49 --> 00:26:51 expansion is increasing, whereas somewhere
00:26:51 --> 00:26:54 else it might be slowing down
00:26:54 --> 00:26:56 the expansion of the universe. Um,
00:26:58 --> 00:27:00 Andrew Dunkley: yeah, sorry, go on.
00:27:00 --> 00:27:02 Professor Fred Watson: No, that would be a universe that's not
00:27:02 --> 00:27:04 isotropic. It's not the same in all
00:27:04 --> 00:27:06 directions, but we assume it's isotropic. So,
00:27:06 --> 00:27:09 uh, that's all we can do in our assumptions
00:27:09 --> 00:27:10 in cosmology.
00:27:10 --> 00:27:13 Andrew Dunkley: We just can't see beyond
00:27:13 --> 00:27:15 what we can see. Which sounds stupid, but
00:27:15 --> 00:27:18 that's the way the universe is. Um,
00:27:18 --> 00:27:20 we've got the known universe and then the
00:27:20 --> 00:27:20 rest of the.
00:27:21 --> 00:27:24 Professor Fred Watson: That's right, basically. And the rest might
00:27:24 --> 00:27:25 be a lot bigger than the known universe.
00:27:25 --> 00:27:27 Andrew Dunkley: Yeah, but we just don't know. Um,
00:27:29 --> 00:27:30 the only thing I thought of is, like, you
00:27:30 --> 00:27:32 look at Earth's atmosphere and as you go out,
00:27:32 --> 00:27:35 it fins. And so there's no defined
00:27:35 --> 00:27:38 line between space and
00:27:38 --> 00:27:41 the Earth proper. Could the
00:27:41 --> 00:27:43 universe be of the same ilk?
00:27:44 --> 00:27:47 Professor Fred Watson: Yes, but that would imply that space time
00:27:47 --> 00:27:49 just sort of keeps. Just keeps on going. It
00:27:49 --> 00:27:50 just might be empty.
00:27:51 --> 00:27:53 Uh, yeah,
00:27:53 --> 00:27:56 uh, we don't know.
00:27:56 --> 00:27:57 Andrew Dunkley: We don't know.
00:27:57 --> 00:27:59 Professor Fred Watson: Why are you asking us? We don't know.
00:28:02 --> 00:28:05 Andrew Dunkley: Uh, um, thank you, Ken. Uh, very
00:28:05 --> 00:28:07 thought provoking question and thanks for
00:28:07 --> 00:28:08 sending it in.
00:28:08 --> 00:28:10 If you have questions for us, please send
00:28:10 --> 00:28:11 them to us via our website,
00:28:12 --> 00:28:14 spacenutspodcast.com spacenuts
00:28:14 --> 00:28:16 IO there's a little button at the top called
00:28:16 --> 00:28:19 AMA M and that's what you click on to
00:28:20 --> 00:28:22 send us text and audio questions. If you've
00:28:22 --> 00:28:23 got a device with a microphone, you're all
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00:28:32 --> 00:28:34 send us a text question. Just fill in the
00:28:34 --> 00:28:37 blanks. And while you're there, have a look
00:28:37 --> 00:28:39 around, visit the shop, get something from
00:28:39 --> 00:28:42 yourself. Um, you know, whatever you like.
00:28:42 --> 00:28:44 And we're done. Fred Watson, thank you so
00:28:44 --> 00:28:45 much. That was a tough one.
00:28:47 --> 00:28:50 Professor Fred Watson: Yeah, well, we, you know, uh, Space
00:28:50 --> 00:28:52 Nuts always probes the limits of knowledge.
00:28:52 --> 00:28:54 We. It does. Ah, that's what we.
00:28:54 --> 00:28:56 Andrew Dunkley: Unfortunately, I have such limited knowledge,
00:28:56 --> 00:28:58 I'm not very helpful. But I'm glad you're
00:28:58 --> 00:28:58 here.
00:28:59 --> 00:29:01 Professor Fred Watson: No, you are very helpful and, um, so are our
00:29:01 --> 00:29:04 listeners because they keep on probing, which
00:29:04 --> 00:29:04 is great.
00:29:04 --> 00:29:06 Andrew Dunkley: They do indeed. All right, Fred Watson,
00:29:06 --> 00:29:07 thanks very much. We'll catch you on the next
00:29:07 --> 00:29:08 episode.
00:29:08 --> 00:29:10 Professor Fred Watson: Sounds great. Thanks, Andrew.
00:29:10 --> 00:29:11 Andrew Dunkley: Professor Fred Watson Watson, astronomer at
00:29:11 --> 00:29:13 large. And thanks to Huw in the studio, who
00:29:13 --> 00:29:15 couldn't be with us today because he's been
00:29:15 --> 00:29:17 expanding at an accelerating rate. So he was.
00:29:17 --> 00:29:19 Enter the gym. And from me, Andrew Dunkley.
00:29:19 --> 00:29:21 Thanks for your company. We'll see you on the
00:29:21 --> 00:29:23 next episode of Space Nuts.
00:29:23 --> 00:29:23 Professor Fred Watson: Bye. Bye.
00:29:24 --> 00:29:27 Andrew Dunkley: Uh, you'll be listening to the Space Nuts
00:29:27 --> 00:29:30 podcast, available at
00:29:30 --> 00:29:32 Apple Podcasts, Spotify,
00:29:32 --> 00:29:34 iHeartRadio or your favourite podcast
00:29:34 --> 00:29:36 player. You can also stream on
00:29:36 --> 00:29:38 demand@bytes.comm this
00:29:38 --> 00:29:41 Professor Fred Watson: has been another quality podcast production
00:29:41 --> 00:29:42 from bytes.um.com.