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Cosmic Queries: Time Dilation, Black Holes, and Gravastars
In this thought-provoking Q&A edition of Space Nuts , hosts Andrew Dunkley and Professor Fred Watson tackle a range of intriguing questions from listeners around the globe. From the complexities of time dilation near supergiant stars to the mysteries surrounding black holes and the hypothetical concept of gravastars, this episode is a deep dive into the fabric of our universe.
Episode Highlights:
- Time Dilation Near Supergiants: Andrew and Fred discuss the effects of gravity on time near supergiant stars and whether significant time dilation occurs compared to black holes.
- Black Holes and Stars: A listener inquires why black holes can’t revert to stars, prompting a fascinating exploration of singularity and the structure of stars.
- Understanding Atoms and Black Holes: The hosts clarify the nature of atoms, free space, and how density calculations relate to black holes, addressing the paradox of infinite density.
- Redshift Limits and Gravastars: The episode wraps up with an examination of redshift limits in the expanding universe and a discussion about the theoretical existence of gravastars, including their implications for our understanding of cosmic phenomena.
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Stay curious, keep looking up, and join us next time for more stellar insights and cosmic wonders. Until then, clear skies and happy stargazing.
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Episode link: https://play.headliner.app/episode/30648493?utm_source=youtube
00:00:00 --> 00:00:01 Hello again. Thanks for joining us. This
00:00:01 --> 00:00:04 is Space Nuts Q&A edition. My name is
00:00:04 --> 00:00:05 Andrew Dunley. This will be our last
00:00:06 --> 00:00:09 official show for 2025. We'll go into a
00:00:09 --> 00:00:12 short recess and be back with you early
00:00:12 --> 00:00:15 in the new year. Uh but we've got some
00:00:15 --> 00:00:17 questions to nail down before any of
00:00:17 --> 00:00:20 that happens. And we've got a whole
00:00:20 --> 00:00:22 bunch of topics that seem to have
00:00:22 --> 00:00:25 stirred the imaginations of uh our
00:00:25 --> 00:00:27 audience. Uh Andrew wants to know about
00:00:27 --> 00:00:29 time dilation of stars.
00:00:29 --> 00:00:32 Uh Adriano is talking black holes
00:00:32 --> 00:00:36 becoming stars. Uh Ishtto uh is wanting
00:00:36 --> 00:00:39 to ask about free space.
00:00:40 --> 00:00:41 H
00:00:41 --> 00:00:43 I always thought it was expensive
00:00:43 --> 00:00:45 officially all the space around where we
00:00:45 --> 00:00:49 live. Y and Ggo red shift and graars. We
00:00:49 --> 00:00:51 will tackle all of that in this edition
00:00:51 --> 00:00:53 of Space Nuts.
00:00:53 --> 00:00:58 >> 15 seconds. Guidance is internal. 10 9
00:00:58 --> 00:00:59 ignition sequence start.
00:00:59 --> 00:01:00 >> Space nuts.
00:01:00 --> 00:01:03 >> 5 4 3 2
00:01:03 --> 00:01:05 >> 1 2 3 4 5 5 4 3 2 1
00:01:05 --> 00:01:06 >> Space nuts.
00:01:06 --> 00:01:09 >> Astronauts report. It feels good.
00:01:09 --> 00:01:11 >> And here he is again. It's Professor
00:01:11 --> 00:01:13 Fred Watson, an astronomer at large.
00:01:13 --> 00:01:15 Hello, Fred.
00:01:15 --> 00:01:16 >> Hello, Andrew.
00:01:16 --> 00:01:17 >> Good to see you again.
00:01:18 --> 00:01:19 >> Fancy seeing you.
00:01:19 --> 00:01:21 >> Yeah. How odd. How strange.
00:01:21 --> 00:01:24 >> How strange. Hm. Uh getting ready for
00:01:24 --> 00:01:26 your Christmas break. I mean, you've
00:01:26 --> 00:01:27 just come back from a break, so you'd
00:01:27 --> 00:01:31 be, you know, probably
00:01:31 --> 00:01:34 feeling rather relaxed. Well, no. Uh
00:01:34 --> 00:01:36 because only the last six days weren't
00:01:36 --> 00:01:38 work.
00:01:38 --> 00:01:38 >> Ah.
00:01:38 --> 00:01:40 >> Yeah.
00:01:40 --> 00:01:42 So, um No, that's not quite true because
00:01:42 --> 00:01:44 we did have some time off with my family
00:01:44 --> 00:01:46 in Scotland. Um but we did have a proper
00:01:46 --> 00:01:48 holiday at the end of our trip. But yes,
00:01:48 --> 00:01:50 we did two months of pretty hard work.
00:01:50 --> 00:01:52 Ku had a tour in Japan and then uh the
00:01:52 --> 00:01:54 conference in Ireland and a few other
00:01:54 --> 00:01:57 things like that that um kept us busy.
00:01:57 --> 00:01:57 So uh
00:01:58 --> 00:01:59 >> if you if you want to call international
00:01:59 --> 00:02:02 travel a job that's you know that's
00:02:02 --> 00:02:04 fine.
00:02:04 --> 00:02:05 >> Um
00:02:05 --> 00:02:07 >> want to call it work.
00:02:07 --> 00:02:09 >> Um if you Yeah. But when you've got a
00:02:10 --> 00:02:11 tour group when you got 20 people who
00:02:11 --> 00:02:15 you were entertained for a month or it's
00:02:15 --> 00:02:18 actually three and a half weeks. Um it
00:02:18 --> 00:02:21 is work. Yeah. Yeah. Well, we've got a
00:02:21 --> 00:02:23 similar problem in the coming week or
00:02:23 --> 00:02:25 two with four grandchildren that we're
00:02:25 --> 00:02:26 taking to the co.
00:02:26 --> 00:02:28 >> Yeah. To be honest, I'd rather have 20
00:02:28 --> 00:02:30 tourists than four grandchildren.
00:02:30 --> 00:02:31 Although my grandchildren are now
00:02:32 --> 00:02:33 totally self-propelled, apart from the
00:02:33 --> 00:02:35 youngest one, Agie. She's on it. She's
00:02:36 --> 00:02:37 she's nine months like yesterday
00:02:37 --> 00:02:38 actually.
00:02:38 --> 00:02:38 >> Anyway,
00:02:38 --> 00:02:41 >> anyway, yes,
00:02:41 --> 00:02:44 >> it's a matter of But we Yeah. So, we The
00:02:44 --> 00:02:46 bottom line is we will have a relaxing
00:02:46 --> 00:02:48 end of year break, I hope.
00:02:48 --> 00:02:49 >> Very good.
00:02:49 --> 00:02:51 Um, you mentioned Edinburgh. Well, uh,
00:02:51 --> 00:02:54 our first question comes from Andrew in
00:02:54 --> 00:02:56 Edinburgh. Uh, he says, "I have a
00:02:56 --> 00:02:58 two-part question about, uh, the gravity
00:02:58 --> 00:03:00 and subsequent d time dilation that
00:03:00 --> 00:03:03 occurs in and around super giant stars.
00:03:03 --> 00:03:05 If the super giants can collapse into
00:03:05 --> 00:03:08 black holes, then they must have as much
00:03:08 --> 00:03:10 or even more mass than the resulting
00:03:10 --> 00:03:12 black hole just spread over a much
00:03:12 --> 00:03:15 larger area." Uh, I guess my question
00:03:15 --> 00:03:18 is, is there significant time dilation
00:03:18 --> 00:03:21 near these stars or are they simply not
00:03:21 --> 00:03:23 dense enough to have meaningful amounts
00:03:23 --> 00:03:26 of time dilation? If they do, it's weird
00:03:26 --> 00:03:29 that it never comes up. And a slight
00:03:29 --> 00:03:31 followup would be, what about time
00:03:32 --> 00:03:34 dilation within the star itself?
00:03:34 --> 00:03:37 Presumably near the core of these stars,
00:03:37 --> 00:03:40 the density ramps right up. Does a large
00:03:40 --> 00:03:42 difference in time dilation within a
00:03:42 --> 00:03:45 star have any impact on how it behaves?
00:03:45 --> 00:03:47 Hope that all makes sense. Thanks. Love
00:03:47 --> 00:03:50 the show. That's Andrew in Edinburgh.
00:03:50 --> 00:03:55 >> They're great questions. Um um
00:03:55 --> 00:03:59 I'm just not sure about
00:03:59 --> 00:04:02 the first sentence. If the super giants
00:04:02 --> 00:04:05 can collapse into black holes, then they
00:04:05 --> 00:04:08 must have as much or even more mass than
00:04:08 --> 00:04:09 the resulting black hole. Yeah. Okay.
00:04:09 --> 00:04:11 I've read that properly now. Uh just
00:04:11 --> 00:04:11 spread.
00:04:12 --> 00:04:13 >> Maybe I didn't read it properly.
00:04:13 --> 00:04:15 >> No, it's all right. No, it's it's fine.
00:04:15 --> 00:04:17 Um so, so yeah, Andrew's first question
00:04:18 --> 00:04:19 is there significant time dilation near
00:04:20 --> 00:04:23 these stars? And the answer is yes. Uh
00:04:23 --> 00:04:26 the there would be. Um um it's I mean
00:04:26 --> 00:04:30 the time dilation in a black hole is so
00:04:30 --> 00:04:33 great that uh to an outside observer,
00:04:33 --> 00:04:36 time stops on the event horizon. uh for
00:04:36 --> 00:04:39 a star because it's it's spread over a
00:04:40 --> 00:04:41 larger volume of space, the time
00:04:41 --> 00:04:43 dilation is nowhere near as great.
00:04:43 --> 00:04:46 >> Uh but time dilation will be something
00:04:46 --> 00:04:48 that you would have to take into account
00:04:48 --> 00:04:51 if you had um a spacecraft orbiting near
00:04:51 --> 00:04:54 a giant star. Um the bottom line is with
00:04:54 --> 00:04:58 and time dilation is is it's a little
00:04:58 --> 00:05:02 bit spooky in the sense that to to the
00:05:02 --> 00:05:06 star itself and to something uh you know
00:05:06 --> 00:05:07 say you've got something in orbit around
00:05:07 --> 00:05:09 this star their time ticking away at the
00:05:09 --> 00:05:11 normal rate the time dilation is only
00:05:11 --> 00:05:13 what you see from the outside.
00:05:13 --> 00:05:15 >> So this is this is basically the same as
00:05:15 --> 00:05:17 we were talking about in the last
00:05:17 --> 00:05:19 episode regarding Mars. Same problem.
00:05:19 --> 00:05:21 >> Yes that's right it is the same thing.
00:05:21 --> 00:05:25 Yeah. So, so time ticks away normally
00:05:25 --> 00:05:27 for the star, but to to watch it from
00:05:27 --> 00:05:30 the outside, you basically see time
00:05:30 --> 00:05:32 ticking away a little bit more slowly.
00:05:32 --> 00:05:35 Um, so so they they would have time
00:05:35 --> 00:05:37 dilation. Um, and Andrew is asking
00:05:37 --> 00:05:39 whether they're not simply not dense
00:05:39 --> 00:05:41 enough to have a meaningful amount of
00:05:41 --> 00:05:44 time dilation. And um, I don't think
00:05:44 --> 00:05:45 that's true. I think that this time
00:05:45 --> 00:05:47 dilation is significant, especially if
00:05:47 --> 00:05:49 you're looking at microsconds as we were
00:05:49 --> 00:05:53 in the last episode. Um yeah. Uh so they
00:05:53 --> 00:05:56 they do and look you're not talking
00:05:56 --> 00:05:58 about time dilation of the kind that was
00:05:58 --> 00:06:01 depicted in Interstellar where you know
00:06:01 --> 00:06:04 time kind of grinds to a halt almost. Uh
00:06:04 --> 00:06:06 it's a it's a more modest amount of time
00:06:06 --> 00:06:08 dilation but it would would actually
00:06:08 --> 00:06:11 happen. And uh Andrew's follow-up
00:06:11 --> 00:06:13 question. What about time dilation
00:06:13 --> 00:06:14 within the star itself? Presumably near
00:06:14 --> 00:06:17 the core this of these stars the density
00:06:17 --> 00:06:19 ramps right up. Does a large difference
00:06:19 --> 00:06:20 in time?
00:06:20 --> 00:06:23 >> I'm not going in there to find out.
00:06:23 --> 00:06:24 >> Does a large difference in time dilation
00:06:24 --> 00:06:27 within a star have any impact on how it
00:06:27 --> 00:06:30 behaves? Um, and there's a curious thing
00:06:30 --> 00:06:33 there because as you uh get near the the
00:06:33 --> 00:06:35 core of an object uh with spherical
00:06:36 --> 00:06:37 symmetry,
00:06:37 --> 00:06:39 um your gravitational field gets less
00:06:39 --> 00:06:42 and less. Uh and in fact, at the center,
00:06:42 --> 00:06:43 you wouldn't feel any gravity. And
00:06:43 --> 00:06:45 that's because everything's pulling you
00:06:45 --> 00:06:48 in the same direction all around. And I
00:06:48 --> 00:06:49 so I believe that time dilation will
00:06:50 --> 00:06:51 probably stop in the middle of a star.
00:06:51 --> 00:06:53 That might be right. So something I've
00:06:53 --> 00:06:56 never thought about before. Uh maybe
00:06:56 --> 00:06:58 that's not true because you you're still
00:06:58 --> 00:07:00 in a gravitational field. The fact that
00:07:00 --> 00:07:02 it cancels out everywhere. I'll check
00:07:02 --> 00:07:04 that one out actually and try and
00:07:04 --> 00:07:06 remember for our first show next year
00:07:06 --> 00:07:07 because that's a really interesting
00:07:07 --> 00:07:09 question. Time dilation in the center of
00:07:09 --> 00:07:11 a star. How does it behave?
00:07:12 --> 00:07:12 >> Yeah.
00:07:12 --> 00:07:13 >> Very interesting. But there wouldn't be
00:07:14 --> 00:07:15 a I I think the bottom line is there
00:07:15 --> 00:07:17 wouldn't be a a big difference in time
00:07:17 --> 00:07:19 dilation from one part of a star to
00:07:19 --> 00:07:21 another. That's that's what I'm trying
00:07:21 --> 00:07:21 to say.
00:07:21 --> 00:07:23 >> But he brings up another interesting
00:07:23 --> 00:07:25 point. You've got time dilation around a
00:07:25 --> 00:07:28 massive star. Yeah. Then it goes, you
00:07:28 --> 00:07:31 know, whatever black hole. Uh the time
00:07:32 --> 00:07:33 dilation changes.
00:07:33 --> 00:07:35 >> Yes, it does. Because um as it
00:07:35 --> 00:07:38 collapses, the the gravitational field
00:07:38 --> 00:07:43 increases. uh in increases in in um sort
00:07:43 --> 00:07:44 of angle in the sense that you know it's
00:07:44 --> 00:07:47 a steeper gravitational uh field as you
00:07:48 --> 00:07:50 get as the black hole collapses. And by
00:07:50 --> 00:07:51 that I'm thinking of the gravitational
00:07:51 --> 00:07:54 well you know this dip in in the in the
00:07:54 --> 00:07:55 trampoline sheet that's the
00:07:55 --> 00:07:57 gravitational well of an object which
00:07:57 --> 00:08:00 turns into something like a plug hole.
00:08:00 --> 00:08:02 Yeah. With water going around it as a
00:08:02 --> 00:08:05 vortex for a black hole. Uh so that's
00:08:05 --> 00:08:06 what I mean by the steepness of the
00:08:06 --> 00:08:09 gravitational field. Um and yes, it is
00:08:09 --> 00:08:11 so steep that the event horizon
00:08:11 --> 00:08:13 delineates where the time dilation
00:08:13 --> 00:08:16 becomes uh such that time appears to
00:08:16 --> 00:08:17 stop on the surface of the event
00:08:17 --> 00:08:18 horizon.
00:08:18 --> 00:08:20 >> Yeah, I've I've seen that demonstration
00:08:20 --> 00:08:23 done with like a a big rubber sheet and
00:08:23 --> 00:08:25 they say that right that's that's the
00:08:25 --> 00:08:27 time space-time continuum. Then they put
00:08:27 --> 00:08:28 a bowling ball in it and they said
00:08:28 --> 00:08:30 that's gravity.
00:08:30 --> 00:08:34 >> Yeah, that's right. Yep. Um I know.
00:08:34 --> 00:08:36 Yeah,
00:08:36 --> 00:08:38 >> it's a simple way of explaining it, but
00:08:38 --> 00:08:41 that's that's what it is. Um I suppose.
00:08:41 --> 00:08:43 >> Um great questions, Andrew, and I hope
00:08:43 --> 00:08:46 all is well in Edinburgh. Um Fred's uh
00:08:46 --> 00:08:48 Fred's home stomping ground. Um
00:08:48 --> 00:08:49 >> yep.
00:08:49 --> 00:08:50 >> Yeah, I'll give you his address and he
00:08:50 --> 00:08:53 can go and rock his roof. This is Bas
00:08:53 --> 00:08:55 Arts with Andrew Dunley and Professor
00:08:55 --> 00:08:57 Fred Watson. Uh we have got an audio
00:08:57 --> 00:09:01 question, Fred. This is from Adriano.
00:09:01 --> 00:09:03 Hi guys, Adrianiano from Florence in
00:09:03 --> 00:09:05 Italy. I have my first question about
00:09:05 --> 00:09:07 black holes. So if I understood
00:09:07 --> 00:09:09 correctly, a star continue to burn his
00:09:09 --> 00:09:12 fuel like hydrogen and helium and there
00:09:12 --> 00:09:14 are nuclear fusions and there is enough
00:09:14 --> 00:09:17 energy for the star to fight against its
00:09:17 --> 00:09:20 own gravitational pool. But at some
00:09:20 --> 00:09:22 point there is not enough fuel and the
00:09:22 --> 00:09:25 star collapse into a black hole. After
00:09:25 --> 00:09:28 this the black hole will start to absorb
00:09:28 --> 00:09:30 material like hydrogen and then it
00:09:30 --> 00:09:34 should have enough energy enough fuel to
00:09:34 --> 00:09:37 have nuclear fusions and to fight
00:09:37 --> 00:09:40 against the gravitational pool but uh so
00:09:40 --> 00:09:43 why a black hole cannot turn back into a
00:09:43 --> 00:09:45 star? I'm sure this is not possible but
00:09:45 --> 00:09:48 I cannot understand why. And also guys
00:09:48 --> 00:09:50 we had a lot of beautiful updates from
00:09:50 --> 00:09:52 the princess. Can we also have some
00:09:52 --> 00:09:54 updates from Fred? Thank you guys.
00:09:54 --> 00:09:55 Bye-bye,
00:09:55 --> 00:09:57 >> Adrianiano. Thank you very much. Um Fred
00:09:57 --> 00:10:01 gave us his update when he got back.
00:10:01 --> 00:10:04 >> But uh yeah, your point is well made. Um
00:10:04 --> 00:10:06 Florence, what a beautiful beautiful
00:10:06 --> 00:10:06 city.
00:10:06 --> 00:10:08 >> Yeah. Isn't it just
00:10:08 --> 00:10:09 >> uh we we visited Florence a few years
00:10:09 --> 00:10:13 ago and uh it was it was
00:10:13 --> 00:10:15 amazing, but it was also terrible timing
00:10:15 --> 00:10:17 because it was All Saints weekend, which
00:10:17 --> 00:10:19 is a 4-day long weekend, and there were
00:10:19 --> 00:10:22 like tens of thousands of people there.
00:10:22 --> 00:10:24 You couldn't move. You absolutely
00:10:24 --> 00:10:28 couldn't move. So, um uh we went to what
00:10:28 --> 00:10:31 was it called? The Ponttovecia. Um and
00:10:31 --> 00:10:32 we couldn't get near it. You just
00:10:32 --> 00:10:36 couldn't. It was um it was insane. Yeah.
00:10:36 --> 00:10:37 We didn't know until we got there.
00:10:37 --> 00:10:40 That's what was happening. But yeah, we
00:10:40 --> 00:10:41 still got to see it. It was a beautiful
00:10:41 --> 00:10:44 place. And all those amazing statues and
00:10:44 --> 00:10:47 Galileo got got up close with Galileo.
00:10:47 --> 00:10:49 >> Very good. Yeah.
00:10:49 --> 00:10:51 >> Yeah. Yeah. Did you see his um I think
00:10:51 --> 00:10:53 it's his it's one of his fingers or his
00:10:53 --> 00:10:54 thumb. I can't remember which is on
00:10:54 --> 00:10:56 display in the science museum there.
00:10:56 --> 00:10:59 >> Oh, no. No. Couldn't get near that. Um
00:10:59 --> 00:11:01 honestly, it was just mayhem. But um
00:11:01 --> 00:11:04 yeah, understandable though. Um all
00:11:04 --> 00:11:06 right, so the bottom line with Adriano's
00:11:06 --> 00:11:10 question is um why can't a black hole
00:11:10 --> 00:11:13 turned back into a star? Um yeah, I
00:11:13 --> 00:11:14 would I would think there'd be all sorts
00:11:14 --> 00:11:16 of reasons why not.
00:11:16 --> 00:11:18 >> Well, that's right. I think once you've
00:11:18 --> 00:11:22 turned into a singularity uh as the um
00:11:22 --> 00:11:26 >> you can't double down. Boom. Boom.
00:11:26 --> 00:11:27 >> Sorry.
00:11:27 --> 00:11:30 >> That you took the words out of my mouth.
00:11:30 --> 00:11:33 >> No, you didn't. Um I mean all bets are
00:11:33 --> 00:11:35 off basically once you once you've gone
00:11:35 --> 00:11:39 into a singularity. Uh and so um I think
00:11:39 --> 00:11:41 you know it's it's a great thought that
00:11:42 --> 00:11:44 um Adriano's had. I and that it's never
00:11:44 --> 00:11:47 occurred to me before, but but you know,
00:11:47 --> 00:11:49 you're talking about hydrogen uh which
00:11:49 --> 00:11:51 certainly would get sucked into a black
00:11:51 --> 00:11:54 hole because a lot of the gas clouds
00:11:54 --> 00:11:57 that um that a black hole um accretion
00:11:57 --> 00:12:00 disc would would draw in and and suck
00:12:00 --> 00:12:04 into the center. Uh that um uh that
00:12:04 --> 00:12:07 that's that's hydrogen. Uh and hydrogen
00:12:07 --> 00:12:09 is the raw material of stars. Why can't
00:12:09 --> 00:12:12 nuclear fusion kick in again and drive
00:12:12 --> 00:12:14 the star back into being a star rather
00:12:14 --> 00:12:16 than a black hole? And I think the
00:12:16 --> 00:12:19 answer is in structure. Um so stars have
00:12:20 --> 00:12:23 quite a complex structure uh to make
00:12:23 --> 00:12:26 them work uh with the the core with all
00:12:26 --> 00:12:28 the nuclear burning taking place. Then
00:12:28 --> 00:12:30 there's a convection zone and then
00:12:30 --> 00:12:32 there's an sort of outer layer before
00:12:32 --> 00:12:33 you get to the photosphere. the layer
00:12:33 --> 00:12:36 that you can see um when you've put
00:12:36 --> 00:12:39 something into a singularity all
00:12:39 --> 00:12:44 structure disappears and um it almost
00:12:44 --> 00:12:48 relates to um an issue that occupied the
00:12:48 --> 00:12:50 mind of Steven Hawking for a while which
00:12:50 --> 00:12:53 is that does information get lost when
00:12:53 --> 00:12:55 when it goes into a black hole
00:12:55 --> 00:12:58 >> and I think there was some argument with
00:12:58 --> 00:12:59 another well-known physicist in fact I
00:13:00 --> 00:13:03 think they had a bet uh which Hawin lost
00:13:03 --> 00:13:06 Um because the um the the b the I think
00:13:06 --> 00:13:08 the bottom line was hawking bet that
00:13:08 --> 00:13:10 information couldn't come out of a black
00:13:10 --> 00:13:12 hole but somebody proved a theory that
00:13:12 --> 00:13:14 information could come out of a black
00:13:14 --> 00:13:15 hole. I think I've got the the right way
00:13:15 --> 00:13:16 round.
00:13:16 --> 00:13:16 >> Okay.
00:13:16 --> 00:13:18 >> But basically it's all completely
00:13:18 --> 00:13:21 mangled in in terms of you know we don't
00:13:21 --> 00:13:23 understand the physics of what would
00:13:23 --> 00:13:25 happen inside a singularity. We just
00:13:25 --> 00:13:27 have no idea what the physical processes
00:13:27 --> 00:13:29 would be and they almost certainly would
00:13:29 --> 00:13:34 rule out hydrogen atoms getting together
00:13:34 --> 00:13:36 uh and with enough temperature to to to
00:13:36 --> 00:13:38 produce the nuclear fusion that we see
00:13:38 --> 00:13:41 in a normal star.
00:13:41 --> 00:13:43 A a black hole is a very abnormal
00:13:43 --> 00:13:46 object. Nothing relates to normal in a
00:13:46 --> 00:13:49 black hole. And so I think that is the
00:13:49 --> 00:13:51 answer to Adriana's question. uh physics
00:13:52 --> 00:13:53 physics doesn't work the way it works on
00:13:54 --> 00:13:55 the outside of a black hole and I think
00:13:55 --> 00:13:57 that's why we don't see black holes
00:13:57 --> 00:13:58 turning into stars.
00:13:58 --> 00:14:01 >> Yeah. Well, there's also the fuel issue
00:14:01 --> 00:14:03 like um you know the the star has
00:14:03 --> 00:14:06 collapsed because of fuel depletion has
00:14:06 --> 00:14:07 it not?
00:14:07 --> 00:14:08 >> Yes, that's right. But what we're saying
00:14:08 --> 00:14:10 and what Adriano is saying is that um
00:14:10 --> 00:14:13 among the stuff that is accreted by the
00:14:13 --> 00:14:15 black hole when it's sitting there
00:14:15 --> 00:14:17 gobbling stuff up, a lot of that is
00:14:17 --> 00:14:20 hydrogen which is the fuel. So, they're
00:14:20 --> 00:14:22 getting more fuel, but they don't any
00:14:22 --> 00:14:24 longer have the process to make it turn
00:14:24 --> 00:14:27 into something that will deliver energy.
00:14:27 --> 00:14:28 >> I think that's the bottom line.
00:14:28 --> 00:14:31 >> I get it. I get it. Okay. Um, great
00:14:32 --> 00:14:35 question though because uh
00:14:35 --> 00:14:37 we we've
00:14:37 --> 00:14:39 been talking black holes for I don't
00:14:39 --> 00:14:41 know how long. Probably since the very
00:14:41 --> 00:14:44 beginning of the time that this podcast
00:14:44 --> 00:14:46 began. And I don't think we've ever been
00:14:46 --> 00:14:47 asked that question before.
00:14:47 --> 00:14:50 >> No, I think that's right. Yeah.
00:14:50 --> 00:14:53 >> Says a lot for our for our listeners,
00:14:53 --> 00:14:55 doesn't it? That they can produce
00:14:55 --> 00:14:57 questions that we've never had before
00:14:57 --> 00:14:59 after however many episodes. Is it? It's
00:14:59 --> 00:15:01 getting on for 500 now.
00:15:01 --> 00:15:02 >> This is 582.
00:15:02 --> 00:15:04 >> Oh, 582. Okay.
00:15:04 --> 00:15:05 >> 582. Yeah.
00:15:05 --> 00:15:07 >> Right. There you go. Getting on for 600.
00:15:07 --> 00:15:10 >> I know. It's nuts. I mean, it's
00:15:10 --> 00:15:11 happening faster because of time
00:15:11 --> 00:15:14 dilation and the fact that we
00:15:14 --> 00:15:15 decided to do two episodes a week
00:15:16 --> 00:15:19 instead of one, but
00:15:19 --> 00:15:20 I think it's nuts by definition, isn't
00:15:20 --> 00:15:23 it? Um, I've got a feeling
00:15:23 --> 00:15:24 >> probably.
00:15:24 --> 00:15:25 >> Yeah.
00:15:25 --> 00:15:27 >> Uh, anyway, thank you, Adriano, and hope
00:15:27 --> 00:15:30 all is well in the beautiful Florence.
00:15:30 --> 00:15:32 This is Space Nuts with Andrew Dunley
00:15:32 --> 00:15:36 and Professor Fred Watson.
00:15:36 --> 00:15:37 Let's take a break from the show to tell
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00:17:08 --> 00:17:10 or you can tap on the link in the show
00:17:10 --> 00:17:12 notes.
00:17:12 --> 00:17:15 >> 3 2 1
00:17:15 --> 00:17:17 >> Space nuts.
00:17:17 --> 00:17:18 >> Our next question doesn't come from
00:17:18 --> 00:17:21 Italy. It comes from Slovenia. Um Russia
00:17:21 --> 00:17:22 next door.
00:17:22 --> 00:17:24 >> Yeah. Uh I am listening to your podcast
00:17:24 --> 00:17:27 while driving to and from work. Great
00:17:27 --> 00:17:29 show. I hope you managed to keep control
00:17:29 --> 00:17:31 because you know this gets a bit crazy
00:17:31 --> 00:17:33 sometimes. Uh I'm curious about wait for
00:17:33 --> 00:17:36 it Fred black holes. Uh we know that an
00:17:36 --> 00:17:38 atom is actually a lot of free space
00:17:38 --> 00:17:41 where electrons fly around. Uh
00:17:41 --> 00:17:44 eliminating that we probably probably
00:17:44 --> 00:17:47 get a neutron star uh with high density.
00:17:47 --> 00:17:49 But what about a black hole? How does
00:17:49 --> 00:17:52 this work? Where is the free space uh
00:17:52 --> 00:17:53 that can be squeezed even further to get
00:17:54 --> 00:17:56 a black hole uh get black hole material
00:17:56 --> 00:17:58 and density and to calculate the density
00:17:58 --> 00:18:00 of the black hole? Would it be a correct
00:18:00 --> 00:18:03 assumption to take the event horizon as
00:18:03 --> 00:18:07 the boundary and um based on that
00:18:07 --> 00:18:09 calculate the volume or is it something
00:18:09 --> 00:18:12 else? Um thank you. Best regards Isht.
00:18:12 --> 00:18:14 Um another black hole question. Not
00:18:14 --> 00:18:17 surprising we get a lot of them.
00:18:17 --> 00:18:21 >> We do. Yeah. So um the it's a it's a
00:18:21 --> 00:18:23 great question and I you that's
00:18:23 --> 00:18:25 absolutely right. An atom is a lot of
00:18:25 --> 00:18:27 free space empty space
00:18:27 --> 00:18:29 >> uh with cloud of electrons doing their
00:18:29 --> 00:18:33 quantum thing. Um if you collapse the
00:18:33 --> 00:18:35 space down so that only the electrons
00:18:35 --> 00:18:37 are pushing uh the atoms apart, you've
00:18:37 --> 00:18:39 got a white dwarf star uh which is
00:18:39 --> 00:18:42 called electron degenerate. Uh and if
00:18:42 --> 00:18:43 you get rid of the electrons, then you
00:18:43 --> 00:18:45 get a neutron star. Exactly as Ishtuk
00:18:45 --> 00:18:49 says uh with um very high density uh
00:18:49 --> 00:18:52 where only the neutrons keep the thing
00:18:52 --> 00:18:54 from collapsing into a black hole. But
00:18:54 --> 00:18:58 with a black hole um well the free space
00:18:58 --> 00:19:00 is is is basically disappeared down the
00:19:00 --> 00:19:05 black hole. Um it's uh it's and in terms
00:19:05 --> 00:19:09 of its density, you have a definition of
00:19:09 --> 00:19:12 a black hole. Uh, one of the definitions
00:19:12 --> 00:19:13 is a point in space with infinite
00:19:14 --> 00:19:16 density. So, the volume the volume is
00:19:16 --> 00:19:18 zero. See, Jordi Jordi thinks that as
00:19:18 --> 00:19:21 well. He does. Gosh, I don't know what's
00:19:21 --> 00:19:22 happening out there, but
00:19:22 --> 00:19:23 >> yeah,
00:19:23 --> 00:19:25 >> I love it.
00:19:25 --> 00:19:27 >> Oh, we had to hear we had to hear him
00:19:27 --> 00:19:29 from the last show of the year, didn't
00:19:29 --> 00:19:29 he?
00:19:29 --> 00:19:32 >> Last show of the year. That's right.
00:19:32 --> 00:19:34 >> In full flight.
00:19:34 --> 00:19:36 >> Um, so yes, so it's a point of infinite
00:19:36 --> 00:19:39 density. So um it's a comment about
00:19:39 --> 00:19:41 calculating the density of the black
00:19:41 --> 00:19:42 hole. Would it be a correct assumption
00:19:42 --> 00:19:44 to take the event horizon as the
00:19:44 --> 00:19:47 boundary? Uh no it wouldn't. The event
00:19:47 --> 00:19:49 horizon is just that imaginary point
00:19:49 --> 00:19:52 where of no return. Uh and the volume is
00:19:52 --> 00:19:54 zero. Uh the volume of the black hole is
00:19:54 --> 00:19:57 zero which is how the the density gets
00:19:57 --> 00:20:01 infinite because um mass over density
00:20:01 --> 00:20:03 sorry mass over volume is density. The
00:20:03 --> 00:20:06 mass is a is a parameter. Um, but the
00:20:06 --> 00:20:08 volume is zero. I have no idea what's
00:20:08 --> 00:20:09 happening out there. I drew it with
00:20:10 --> 00:20:11 Jordy, but he obviously likes this
00:20:11 --> 00:20:12 conversation.
00:20:12 --> 00:20:16 >> Yes. Yes, he does. He wants in.
00:20:16 --> 00:20:17 >> Yeah.
00:20:17 --> 00:20:21 >> Oh dear. Um, yeah. Look, I still don't
00:20:21 --> 00:20:23 get
00:20:23 --> 00:20:26 >> receding into the distance.
00:20:26 --> 00:20:29 >> Yeah. Probably chasing a snake. Um,
00:20:29 --> 00:20:30 yeah. Uh,
00:20:30 --> 00:20:34 >> go ahead, Andrew. No, it's it's hard to
00:20:34 --> 00:20:36 get your head around something like a
00:20:36 --> 00:20:38 black hole
00:20:38 --> 00:20:41 having
00:20:41 --> 00:20:45 no density.
00:20:45 --> 00:20:46 >> No volume.
00:20:47 --> 00:20:49 >> It's got no size. It's got zero
00:20:49 --> 00:20:50 dimensions.
00:20:50 --> 00:20:53 >> I mean, we we we give them names based
00:20:53 --> 00:20:56 on size and yet it has no size. Has no
00:20:56 --> 00:20:56 volume.
00:20:56 --> 00:20:58 >> Super massive. Yeah. Well, but it's the
00:20:58 --> 00:21:00 mass. That's the thing. So the mass is
00:21:00 --> 00:21:02 defined for a black hole. It's one of
00:21:02 --> 00:21:03 the properties that they have. The
00:21:03 --> 00:21:06 there's this thing called the the no
00:21:06 --> 00:21:09 hair theorem uh which I like very much.
00:21:09 --> 00:21:10 >> Yeah.
00:21:10 --> 00:21:11 >> And it's about you know
00:21:11 --> 00:21:12 >> would that wouldn't
00:21:12 --> 00:21:15 >> Yeah, that's right. Which there's it's
00:21:15 --> 00:21:18 about the very few parameters that you
00:21:18 --> 00:21:20 can get from a black hole. I think it's
00:21:20 --> 00:21:22 mass, charge and spin. I think that's
00:21:22 --> 00:21:25 all you know about a black hole. Um
00:21:25 --> 00:21:27 because the volume's zero and that's why
00:21:27 --> 00:21:29 the density is zero. Density is mass
00:21:29 --> 00:21:31 over volume. Volume zero. So the density
00:21:31 --> 00:21:33 goes to infinite infinity but you can
00:21:34 --> 00:21:36 vary the mass and that's why we talk
00:21:36 --> 00:21:37 about super massive black holes and
00:21:37 --> 00:21:39 intermediate mass black holes and things
00:21:39 --> 00:21:40 of that sort.
00:21:40 --> 00:21:43 >> Okay. So what was the answer to the
00:21:43 --> 00:21:44 question?
00:21:44 --> 00:21:48 >> Uh no. Right. Right. What was the
00:21:48 --> 00:21:51 question again? Hang on. Uh yeah. Would
00:21:51 --> 00:21:53 it be yes would it be correct assumption
00:21:53 --> 00:21:55 to take the event horizon as a boundary
00:21:55 --> 00:21:56 and and use that to calculate the
00:21:56 --> 00:21:58 volume? No. The event horizon is an
00:21:58 --> 00:22:02 imaginary sphere that um is where the
00:22:02 --> 00:22:03 thing turns black basically because no
00:22:04 --> 00:22:05 light can escape
00:22:05 --> 00:22:07 >> precisely.
00:22:07 --> 00:22:10 Um hope that helped is uh it's a great
00:22:10 --> 00:22:11 question.
00:22:11 --> 00:22:13 >> It is terrific question. Uh just a very
00:22:13 --> 00:22:16 difficult subject cuz we we just don't
00:22:16 --> 00:22:19 know a hell of a lot about black holes.
00:22:19 --> 00:22:23 They're just such a mysterious and
00:22:23 --> 00:22:26 weird object. And um we we're we're
00:22:26 --> 00:22:28 still trying to gather information about
00:22:28 --> 00:22:30 them and they just keep throwing up
00:22:30 --> 00:22:32 these curve balls at us and not letting
00:22:32 --> 00:22:34 us in. Not that you want to go in, but
00:22:34 --> 00:22:36 you know what I mean.
00:22:36 --> 00:22:37 >> Yes, that's right.
00:22:38 --> 00:22:39 >> Yeah, quite s.
00:22:39 --> 00:22:42 >> All right, thanks.
00:22:42 --> 00:22:44 >> Time to take a break from the show to
00:22:44 --> 00:22:46 tell you about our sponsor, NordVPN. If
00:22:46 --> 00:22:49 you're online, your data is always at
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00:22:56 --> 00:22:58 private network is the way to go. Uh
00:22:58 --> 00:23:00 there are lots of hackers and trackers
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00:24:09 --> 00:24:11 Nuts at the checkout.
00:24:11 --> 00:24:12 >> Space Nuts.
00:24:12 --> 00:24:15 >> We have one more question to finish
00:24:15 --> 00:24:19 things off for 2025 and it it's a real
00:24:19 --> 00:24:21 European flavor for this episode. This
00:24:21 --> 00:24:22 is Ggo.
00:24:22 --> 00:24:25 >> Greetings gentlemen. GGO from Slovakia
00:24:25 --> 00:24:27 here. I have a question about red
00:24:27 --> 00:24:30 shifting. Does it have a limit? Is there
00:24:30 --> 00:24:32 a point beyond which light cannot be
00:24:32 --> 00:24:34 stretched any further? If so, what
00:24:34 --> 00:24:36 happens if the light continues to travel
00:24:36 --> 00:24:39 through expanding space? And the second
00:24:39 --> 00:24:41 question, could you talk a bit about
00:24:41 --> 00:24:44 gra? Do you think they might be real?
00:24:44 --> 00:24:46 Uh, thank you for your time and for the
00:24:46 --> 00:24:48 great show. Bye.
00:24:48 --> 00:24:52 >> Thanks, Ggo. Uh, yeah, it's we an
00:24:52 --> 00:24:55 eclectic mix of nationalities this week.
00:24:55 --> 00:24:56 Yeah, it's terrific.
00:24:56 --> 00:24:57 >> Yeah, it's great.
00:24:57 --> 00:25:00 >> Uh, so two questions he's um he's thrown
00:25:00 --> 00:25:03 into the mix. Um, yeah. Is there a limit
00:25:03 --> 00:25:06 on red shift? Um,
00:25:06 --> 00:25:09 yeah, good one. So,
00:25:09 --> 00:25:12 uh, yeah, it is a good question. I mean,
00:25:12 --> 00:25:19 so, so red shift as a term we define as
00:25:19 --> 00:25:20 being due to the expansion of the
00:25:20 --> 00:25:23 universe. Um, and it's slightly
00:25:23 --> 00:25:26 different from the Doppler shift. Uh,
00:25:26 --> 00:25:28 Doppler shift is something we understand
00:25:28 --> 00:25:30 well. It's the way the light changes
00:25:30 --> 00:25:32 wavelength from a moving object. But
00:25:32 --> 00:25:34 with red shift, we're talking about
00:25:34 --> 00:25:36 space itself rather than rather than
00:25:36 --> 00:25:38 objects moving through space. We're
00:25:38 --> 00:25:40 talking about the way space behaves. Uh
00:25:40 --> 00:25:43 and so it's a a much more fundamental
00:25:43 --> 00:25:46 thing than the Doppler shift. So in a
00:25:46 --> 00:25:49 sense, um there's already a limit to red
00:25:49 --> 00:25:55 shift. Uh but it's one that is exactly
00:25:55 --> 00:25:58 related to the age of the universe. Um,
00:25:58 --> 00:26:02 so and for so what I'm thinking of here
00:26:02 --> 00:26:05 is the the uh cosmic microwave
00:26:06 --> 00:26:08 background radiation. That's the wall of
00:26:08 --> 00:26:11 radiation which corresponds to the
00:26:11 --> 00:26:15 brightness of the big bang fireball
00:26:15 --> 00:26:17 which we're still seeing because as we
00:26:17 --> 00:26:19 look further into space, we look back in
00:26:19 --> 00:26:22 time. So everywhere in space we see this
00:26:22 --> 00:26:24 wall of radiation which is now in the
00:26:24 --> 00:26:26 microwave region of the spectrum which
00:26:26 --> 00:26:28 is why we call it the cosmic microwave
00:26:28 --> 00:26:29 background radiation.
00:26:29 --> 00:26:29 >> Yeah.
00:26:29 --> 00:26:34 >> And so um it's if I remember rightly
00:26:34 --> 00:26:38 that is basically the visible flash of
00:26:38 --> 00:26:42 the big bang because it was it was
00:26:42 --> 00:26:46 basically a a visible light flash. It's
00:26:46 --> 00:26:50 the visible flash redshifted by I think
00:26:50 --> 00:26:54 about 1300 times. So everything in the
00:26:54 --> 00:26:57 universe must have a that we can observe
00:26:57 --> 00:27:00 must have a red shift less than that. Uh
00:27:00 --> 00:27:03 I think 1300 is the the number that
00:27:03 --> 00:27:05 comes into my mind. I've looked at this
00:27:05 --> 00:27:07 for a long time. Um but it's visible
00:27:07 --> 00:27:11 light um whose uh which whose waves have
00:27:11 --> 00:27:14 been stretched by that amount to give us
00:27:14 --> 00:27:17 microwaves. So stretched about 1300
00:27:17 --> 00:27:19 times thereabouts.
00:27:19 --> 00:27:21 Now um
00:27:21 --> 00:27:24 as the universe expands and time goes on
00:27:24 --> 00:27:27 that number will increase not by much
00:27:27 --> 00:27:31 might become 131 or 135 but as time goes
00:27:31 --> 00:27:34 on that number is increasing. So
00:27:34 --> 00:27:37 >> in a sense that's a limit to red shift.
00:27:37 --> 00:27:39 Uh physically though I don't think there
00:27:39 --> 00:27:41 is a limit. You could, you know, if if
00:27:41 --> 00:27:43 you expand the universe, if you're
00:27:43 --> 00:27:44 talking about 40 billion years into the
00:27:44 --> 00:27:46 future and the universe is expanding
00:27:46 --> 00:27:48 more, yes, the cosmic microwave
00:27:48 --> 00:27:50 background is going to be the cosmic
00:27:50 --> 00:27:53 long wavelength radio background. Uh,
00:27:53 --> 00:27:57 and so it's uh it's the the wavelength
00:27:57 --> 00:27:59 will have stretched more. Uh, so there
00:27:59 --> 00:28:03 isn't a physical limit, but there is a a
00:28:03 --> 00:28:06 limit in the real universe. uh simply
00:28:06 --> 00:28:07 because of the age of the universe. The
00:28:07 --> 00:28:10 universe hasn't hasn't expanded for long
00:28:10 --> 00:28:12 enough for the red shift to be more than
00:28:12 --> 00:28:14 about 1300.
00:28:14 --> 00:28:17 >> Right. Okay. Yeah. Got it.
00:28:17 --> 00:28:19 >> Good. What was the other thing? Oh,
00:28:19 --> 00:28:19 gravity stars.
00:28:20 --> 00:28:21 >> Oh, grav stars. Yeah, we've had we've
00:28:21 --> 00:28:24 had questions about gravis stars before
00:28:24 --> 00:28:26 more than once. Um it it seems to be
00:28:26 --> 00:28:28 something that sort of captured the
00:28:28 --> 00:28:31 imagination of uh of people that are so
00:28:31 --> 00:28:33 interested in astronomy and space
00:28:33 --> 00:28:36 science. So, I suppose we should start
00:28:36 --> 00:28:39 by reminding people what a graar is
00:28:39 --> 00:28:40 supposed to be because I don't think
00:28:40 --> 00:28:42 we've ever found one.
00:28:42 --> 00:28:45 >> No, that's correct. Um, I'm I'm going to
00:28:45 --> 00:28:47 read from uh that font of all knowledge,
00:28:47 --> 00:28:51 Wikipedia, who I do subscribe to uh
00:28:51 --> 00:28:52 despite the fact that they keep asking
00:28:52 --> 00:28:54 me for another subscription. Anyway,
00:28:54 --> 00:28:55 that's probably because I've got more
00:28:55 --> 00:28:58 than one username. Never mind. Let me
00:28:58 --> 00:29:01 read from Wikipedia. In astrophysics,
00:29:01 --> 00:29:04 the graar which is a blend word of
00:29:04 --> 00:29:07 gravitational vacuum star is an object
00:29:07 --> 00:29:11 hypothesized in a 2001 paper by Pavl O
00:29:11 --> 00:29:16 Mazour and Emil Moah as an alternative
00:29:16 --> 00:29:19 to the black hole theory. It has the
00:29:19 --> 00:29:21 usual black hole metric outside of the
00:29:21 --> 00:29:23 horizon and a metric is just a way of
00:29:23 --> 00:29:27 describing space but ditter metric
00:29:27 --> 00:29:30 inside and that's a different one. Don't
00:29:30 --> 00:29:32 worry about that. A typical grav star is
00:29:32 --> 00:29:36 as big as London but weighs 10 solar
00:29:36 --> 00:29:37 masses.
00:29:37 --> 00:29:38 >> Why?
00:29:38 --> 00:29:40 >> Yeah. So a neutron star would be about
00:29:40 --> 00:29:42 the size of London but weigh one solar
00:29:42 --> 00:29:44 mass basically.
00:29:44 --> 00:29:46 >> Didn't they find one in a sewer? Um,
00:29:46 --> 00:29:47 they called it a fatburgg or something.
00:29:48 --> 00:29:50 >> Fatburgg. That's right. Yeah. Which was
00:29:50 --> 00:29:52 just about to turn into a graver star.
00:29:52 --> 00:29:56 Yes. Um, on the horizon there is an
00:29:56 --> 00:29:59 ultra thin, incredibly tight shell of
00:29:59 --> 00:30:03 entirely new unique exotic matter named
00:30:03 --> 00:30:05 Galactic Flubber.
00:30:05 --> 00:30:07 >> I was close.
00:30:07 --> 00:30:09 >> You weren't far off. That's right. Which
00:30:09 --> 00:30:11 is the next thing to a fatburg. Yeah.
00:30:11 --> 00:30:13 Anyway, continuing to read. This
00:30:13 --> 00:30:15 solution to the Einstein equations is
00:30:15 --> 00:30:18 stable and there's no singularities
00:30:18 --> 00:30:20 which we've just been talking about
00:30:20 --> 00:30:23 singularities points of zero volume.
00:30:23 --> 00:30:25 Instead, a grav star is filled with
00:30:25 --> 00:30:28 either dark energy or with vacuum energy
00:30:28 --> 00:30:30 but also vacuum
00:30:30 --> 00:30:33 only the inside one 10 to the 44 times
00:30:33 --> 00:30:36 denser than the outside. I'm not sure
00:30:36 --> 00:30:37 how you can have a vacuum that's 10 to
00:30:38 --> 00:30:40 the 44 times denser than another one,
00:30:40 --> 00:30:43 but I'll just let that pass. Yes.
00:30:43 --> 00:30:46 >> Uh, as a bonus, further theoretical
00:30:46 --> 00:30:48 considerations of grav stars include the
00:30:48 --> 00:30:51 notion of a nest star, a second graar
00:30:51 --> 00:30:54 nested within the first one. So, that's
00:30:54 --> 00:30:56 the technical definition. I bet you're
00:30:56 --> 00:30:59 no wiser than I am. Um, but the bottom
00:30:59 --> 00:31:03 line is that um um and I'll read again.
00:31:03 --> 00:31:06 Mazour and Matahus suggest that the
00:31:06 --> 00:31:09 violent creation of a grab star might be
00:31:09 --> 00:31:11 an explanation for the origin of our
00:31:11 --> 00:31:14 universe and many other universes
00:31:14 --> 00:31:15 because all the matter from a collapsing
00:31:16 --> 00:31:18 star would implode through the central
00:31:18 --> 00:31:20 hole and explode into a new dimension
00:31:20 --> 00:31:22 and expand forever which would be
00:31:22 --> 00:31:25 consistent with the con current theories
00:31:25 --> 00:31:27 regarding the big bang.
00:31:27 --> 00:31:31 >> Okay. So now that we know what it is.
00:31:31 --> 00:31:33 >> Yeah. Do you think they exist? And will
00:31:34 --> 00:31:35 we ever find one?
00:31:35 --> 00:31:39 >> Uh, no and no, basically. Uh, it's um
00:31:39 --> 00:31:42 it's a it's a an alternative theory for
00:31:42 --> 00:31:43 the Big Bang.
00:31:43 --> 00:31:46 >> Uh, and it's certainly interesting and
00:31:46 --> 00:31:50 uh I you know I I think um uh GGO's
00:31:50 --> 00:31:52 asked us to talk about it and now we
00:31:52 --> 00:31:56 have so so um that's perhaps doing the
00:31:56 --> 00:31:59 best we can. Um interesting. There's
00:31:59 --> 00:32:01 there's just one other sentence I might
00:32:01 --> 00:32:04 like to read. Uh
00:32:04 --> 00:32:09 uh if I can find it. I've lost it now.
00:32:09 --> 00:32:12 Oh yeah. The the new dimension that will
00:32:12 --> 00:32:15 be created in this implosion. The new
00:32:15 --> 00:32:18 dimension exerts an outward pressure on
00:32:18 --> 00:32:21 the Bose Einstein condensate layer and
00:32:21 --> 00:32:23 present prevents it from collapsing
00:32:23 --> 00:32:26 further. So the Bose Einstein
00:32:26 --> 00:32:28 condensate, it sounds as though that's
00:32:28 --> 00:32:30 this thinned crust that it's got rather
00:32:30 --> 00:32:33 than an event horizon. And a Bose
00:32:33 --> 00:32:35 Einstein condensate is really
00:32:35 --> 00:32:37 interesting. I think we've just
00:32:37 --> 00:32:39 celebrated,
00:32:39 --> 00:32:43 is it the 30th anniversary of the first
00:32:43 --> 00:32:46 example of a Bose Einstein condenser
00:32:46 --> 00:32:48 being produced? I think that's right. I
00:32:48 --> 00:32:51 think it's 30 years. I think it's 1995.
00:32:51 --> 00:32:54 Uh what is it? It's a a it's a
00:32:54 --> 00:32:56 condensation of atoms at very low
00:32:56 --> 00:32:59 temperature that behave like one quantum
00:32:59 --> 00:33:02 object. Uh that's the crucial thing. So
00:33:02 --> 00:33:04 they it's almost like entanglement,
00:33:04 --> 00:33:05 Andrew, where you've got quantum
00:33:05 --> 00:33:07 particles being entangled. This is a
00:33:07 --> 00:33:09 whole bunch of stuff that is so
00:33:09 --> 00:33:11 entangled it just looks like one quantum
00:33:11 --> 00:33:14 object and we've we can now create them.
00:33:14 --> 00:33:16 >> Um so that's what they're saying that
00:33:16 --> 00:33:18 maybe this thing is made of a Bose
00:33:18 --> 00:33:20 Einstein condenser. I think this is a
00:33:20 --> 00:33:23 really good way to end uh the year's uh
00:33:23 --> 00:33:25 space nuts episode because it is
00:33:25 --> 00:33:28 completely off the wall and talking
00:33:28 --> 00:33:30 about stuff that is right at the cutting
00:33:30 --> 00:33:32 edge of physics which I love
00:33:32 --> 00:33:34 >> indeed. Uh thank you for your questions
00:33:34 --> 00:33:37 Ggo and uh hope you're well. Uh good to
00:33:37 --> 00:33:39 hear from you. You sent in questions
00:33:39 --> 00:33:41 before so it's nice to catch up. Uh in
00:33:41 --> 00:33:45 fact I think um I think Isht uh has sent
00:33:45 --> 00:33:47 questions in before as well. But uh
00:33:47 --> 00:33:48 yeah, thank you for your questions
00:33:48 --> 00:33:50 everybody for uh contributing to this
00:33:50 --> 00:33:52 the final episode of 2025. Keep the
00:33:52 --> 00:33:54 questions coming in because we're coming
00:33:54 --> 00:33:55 back
00:33:55 --> 00:33:57 >> next year and we'll we'll need some
00:33:57 --> 00:33:59 fresh stuff cuz we're we're down to the
00:33:59 --> 00:34:02 last one or two um which I didn't use
00:34:02 --> 00:34:03 because they all came from the same
00:34:03 --> 00:34:05 source and I like to spread the love a
00:34:05 --> 00:34:07 bit. So um we'll get into those next
00:34:07 --> 00:34:09 year. Uh if you go to our website if
00:34:09 --> 00:34:11 you'd like to send a question in, click
00:34:11 --> 00:34:14 on the AMA link at the top and you can
00:34:14 --> 00:34:16 send text and audio questions there. As
00:34:16 --> 00:34:18 always, please remember to tell us who
00:34:18 --> 00:34:20 you are and where you're from. While
00:34:20 --> 00:34:22 you're at on the website, um check out
00:34:22 --> 00:34:24 how you might be able to support us uh
00:34:24 --> 00:34:27 through various channels. Um whatever
00:34:27 --> 00:34:29 you choose or don't choose to, we're not
00:34:29 --> 00:34:31 going to make you do it. Uh you can
00:34:31 --> 00:34:32 check out the shop as well. That's
00:34:32 --> 00:34:35 another way of supporting us. And so on
00:34:35 --> 00:34:37 and so forth. Um, while I
00:34:37 --> 00:34:39 >> I think Andrew, while you were talking
00:34:39 --> 00:34:40 about the questions, I think we've got a
00:34:40 --> 00:34:43 pending one still from Rusty, which we
00:34:43 --> 00:34:44 should
00:34:44 --> 00:34:46 >> I'm sure we'll take it next year.
00:34:46 --> 00:34:50 >> Yes. Yes, I I recall that. But, um, we I
00:34:50 --> 00:34:51 thought we'd sit on it till the new year
00:34:51 --> 00:34:53 because reading the question will
00:34:53 --> 00:34:59 actually take the pulp of the episode.
00:34:59 --> 00:35:00 >> Thank you, Andrew. Sorry to interrupt
00:35:00 --> 00:35:02 you there. That's okay. No, it's okay.
00:35:02 --> 00:35:04 Um, I just want to say thank you to you,
00:35:04 --> 00:35:06 Fred. Um,
00:35:06 --> 00:35:09 And and I should also um thank Jonty
00:35:10 --> 00:35:12 because he he did a fair chunk of the
00:35:12 --> 00:35:16 show and we also had our guest presenter
00:35:16 --> 00:35:18 Heidi while I was away. So thank you to
00:35:18 --> 00:35:21 Heidi for uh her amazing contribution
00:35:21 --> 00:35:24 because uh it really saved my uh my back
00:35:24 --> 00:35:27 because um there was probably no way in
00:35:27 --> 00:35:28 the world I could have recorded from a
00:35:28 --> 00:35:30 cruise ship and got away with it. But um
00:35:30 --> 00:35:32 yeah, fantastic. Uh we've got a great
00:35:32 --> 00:35:37 team. Um and and you know bring on the
00:35:37 --> 00:35:39 next uh the next year of Space Nuts. And
00:35:39 --> 00:35:41 I look I give him a hard time every
00:35:41 --> 00:35:42 week. I do. But I've got to say thanks
00:35:42 --> 00:35:46 to Hugh in the studio for his um amazing
00:35:46 --> 00:35:48 work. It's not just our podcast that he
00:35:48 --> 00:35:50 looks after. He's got a whole stable of
00:35:50 --> 00:35:53 them. And uh it's it's basically a
00:35:53 --> 00:35:55 full-time job trying to run all this. uh
00:35:55 --> 00:35:57 and you know there's not much money in
00:35:57 --> 00:36:00 it but uh uh there's certainly joy in
00:36:00 --> 00:36:03 putting our skills into something uh in
00:36:03 --> 00:36:06 our semi-retirement um from from radio.
00:36:06 --> 00:36:09 So um yeah but uh also without the
00:36:09 --> 00:36:12 audience we would be nothing. So we send
00:36:12 --> 00:36:16 out our um uh our thanks. We are so
00:36:16 --> 00:36:19 grateful to have you behind us. And I do
00:36:19 --> 00:36:21 keep an eye on the audience through the
00:36:21 --> 00:36:24 Space Nuts podcast group on Facebook
00:36:24 --> 00:36:26 because they uh they spend a lot of time
00:36:26 --> 00:36:27 there talking to each other, sharing
00:36:27 --> 00:36:31 pictures uh and uh posing unusual
00:36:31 --> 00:36:32 questions which occasionally we will
00:36:32 --> 00:36:35 bring up on the show. And special thanks
00:36:35 --> 00:36:37 to our sponsors. We've had a few
00:36:37 --> 00:36:38 sponsors who've been with us for quite
00:36:38 --> 00:36:41 some time now and and you know obviously
00:36:41 --> 00:36:42 we're doing something right if they're
00:36:42 --> 00:36:45 willing to stick with us. So very much
00:36:45 --> 00:36:49 appreciated. Uh thank you Fred. Um thank
00:36:49 --> 00:36:53 you uh Jordy and um we'll talk to you in
00:36:53 --> 00:36:55 the new year.
00:36:55 --> 00:36:56 >> Sounds great. Look forward to it Andrew
00:36:56 --> 00:36:58 and all the very best for the festive
00:36:58 --> 00:36:58 season to you
00:36:58 --> 00:37:01 >> and to you and um thank you very much.
00:37:02 --> 00:37:03 Professor Fred Watson, astronomer at
00:37:03 --> 00:37:05 large. And from me, Andrew Dunley, have
00:37:05 --> 00:37:07 a great Christmas, a happy new year.
00:37:07 --> 00:37:10 We'll see you in 2026. Until then,
00:37:10 --> 00:37:11 bye-bye.
00:37:11 --> 00:37:14 >> Space. your Venus to the Space Nuts
00:37:14 --> 00:37:16 podcast
00:37:16 --> 00:37:19 >> available at Apple Podcasts, Spotify,
00:37:19 --> 00:37:22 iHeart Radio, or your favorite podcast
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00:37:24 --> 00:37:26 byes.com.
00:37:26 --> 00:37:28 This has been another quality podcast
00:37:28 --> 00:37:32 production from byes.com.