Sponsor Link:
This episode of Space Nuts is brought to you with the support of NordVPN . When it's time to do something about your online privacy, use the one we trust - NordVPN . To get our special deal visit nordvpn.com/spacenuts (https://nordvpn.com/spacenuts)
Dark Matter Theories, Solar Origins, and Black Hole Temperatures
In this milestone 600th episode of Space Nuts , hosts Andrew Dunkley and Professor Fred Watson celebrate with a captivating Q&A session , tackling a variety of thought-provoking questions from listeners around the globe. Prepare to dive deep into the mysteries of the universe as they explore intriguing theories and concepts that challenge our understanding of cosmology.
Episode Highlights:
- Dark Matter and Dark Energy: Daryl from South Australia presents a unique theory suggesting a connection between dark matter and dark energy, likening them to opposites with gravitational effects. Andrew and Fred dissect this idea and discuss the fundamental differences between these two cosmic phenomena.
- Where Was the Sun Born? Slaty Bartfast from Norway asks if we could see the Sun's birth by pointing a telescope at its historical coordinates. The hosts explain why this wouldn’t yield any observable results and discuss the concept of solar siblings born in the same gas cloud.
- Black Hole Temperatures: Bjorn from Gothenburg seeks clarification on the temperature of black holes and the material that spirals into them. Andrew and Fred clarify how the extreme heat of accreting material contrasts with the near-absolute zero temperature of the black hole itself.
- The Expansion of Space: Peter from Falun poses a complex question about the nature of space and time in an expanding universe. The hosts unravel the intricacies of how our measurements of distance and time are affected by the universe's expansion.
For more Space Nuts, including our continuously updating newsfeed and to listen to all our episodes, visit our website. (https://www.spacenutspodcast.com/) Follow us on social media at SpaceNutsPod on Facebook, Instagram, and more. We love engaging with our community, so be sure to drop us a message or comment on your favorite platform.
If you’d like to help support Space Nuts and join our growing family of insiders for commercial-free episodes and more, visit spacenutspodcast.com/about (https://www.spacenutspodcast.com/about) .
Stay curious, keep looking up, and join us next time for more stellar insights and cosmic wonders. Until then, clear skies and happy stargazing.
Become a supporter of this podcast: https://www.spreaker.com/podcast/space-nuts-astronomy-insights-cosmic-discoveries--2631155/support (https://www.spreaker.com/podcast/space-nuts-astronomy-insights-cosmic-discoveries--2631155/support?utm_source=rss&utm_medium=rss&utm_campaign=rss) .
Episode link: https://play.headliner.app/episode/31689187?utm_source=youtube
00:00:00 --> 00:00:02 Hi there. Thanks for joining us. My name
00:00:02 --> 00:00:06 is Andrew Dunley and this is Space Nuts
00:00:06 --> 00:00:08 Q&A edition. It also happens to be our
00:00:08 --> 00:00:11 sixth hundth episode, believe it or not.
00:00:11 --> 00:00:14 And what are we doing special today?
00:00:14 --> 00:00:17 Nothing. We're just going to answer a
00:00:17 --> 00:00:20 Well, it happens so often now. Uh we're
00:00:20 --> 00:00:21 just going to answer audience questions.
00:00:21 --> 00:00:23 And we've got a bunch of them. Um the
00:00:24 --> 00:00:26 question of dark matter and dark energy
00:00:26 --> 00:00:28 theory has come up again. Uh, in fact,
00:00:28 --> 00:00:30 one of our listeners has come up with a
00:00:30 --> 00:00:32 theory about dark matter and dark energy
00:00:32 --> 00:00:35 theory. So, we'll investigate that. We
00:00:35 --> 00:00:37 also have a question from somebody using
00:00:37 --> 00:00:40 a very interesting pseudonym. Uh,
00:00:40 --> 00:00:43 finding where our sun was born. I think
00:00:43 --> 00:00:45 we've been down that road before
00:00:45 --> 00:00:47 recently, so they're revisiting that.
00:00:48 --> 00:00:50 The temperature of black holes has been
00:00:50 --> 00:00:52 raised yet again. We talked about that
00:00:52 --> 00:00:55 recently. And Peter has asked us about
00:00:56 --> 00:00:58 the expansion of the universe. That's
00:00:58 --> 00:01:01 all coming up on this edition of Space
00:01:01 --> 00:01:01 Nuts.
00:01:01 --> 00:01:06 >> 15 seconds. Guidance is internal. 10 9g
00:01:06 --> 00:01:08 Ignition sequence start.
00:01:08 --> 00:01:09 >> Space nuts.
00:01:09 --> 00:01:14 >> 5 4 3 2 1 2 3 4 5 5 4 3 2 1
00:01:14 --> 00:01:15 >> Space Nuts.
00:01:15 --> 00:01:18 >> Astronauts report. It feels good. once
00:01:18 --> 00:01:21 again joining us from the oh it's not
00:01:21 --> 00:01:23 the 600th time because we've had time
00:01:23 --> 00:01:26 off so it's probably 592
00:01:26 --> 00:01:28 or something like that maybe I don't
00:01:28 --> 00:01:31 know maybe a few less but um his name is
00:01:31 --> 00:01:32 Fred Watson professor Fred Watson in
00:01:32 --> 00:01:35 fact astronomer at large hi Fred
00:01:35 --> 00:01:37 >> how you doing to see you again
00:01:37 --> 00:01:39 >> good to see you too
00:01:39 --> 00:01:41 >> can you believe it's 600 episodes my
00:01:41 --> 00:01:42 goodness
00:01:42 --> 00:01:44 >> so we because we now have two a week
00:01:44 --> 00:01:46 that you go through a hundred every year
00:01:46 --> 00:01:48 basically doesn't more or less.
00:01:48 --> 00:01:49 >> Yeah.
00:01:49 --> 00:01:51 >> Whereas it used to be every couple of
00:01:51 --> 00:01:52 years. So
00:01:52 --> 00:01:53 >> yes,
00:01:53 --> 00:01:55 >> we're just moving faster. It's it's the
00:01:55 --> 00:01:56 expansion of the universe because it's
00:01:56 --> 00:01:58 accelerating. That's what it is.
00:01:58 --> 00:02:01 >> It's a relative relativistic effect
00:02:01 --> 00:02:04 >> indeed. Uh let us uh get straight into
00:02:04 --> 00:02:06 our questions because we've got a whole
00:02:06 --> 00:02:08 bunch of them. Daryl has sent us in a
00:02:08 --> 00:02:10 question. Good day, Space Nuts. I've
00:02:10 --> 00:02:12 been giving dark energy and dark matter
00:02:12 --> 00:02:15 some thought. If I've got this right,
00:02:15 --> 00:02:17 dark matter matter pushes the universe
00:02:17 --> 00:02:21 apart or away while um dark energy
00:02:21 --> 00:02:24 attracts or brings stuff together. So
00:02:24 --> 00:02:26 could dark matter and dark energy be the
00:02:26 --> 00:02:29 same thing but have uh like a north and
00:02:29 --> 00:02:32 south pole? I.e. dark matter north would
00:02:32 --> 00:02:34 be the particle that clumps together and
00:02:34 --> 00:02:36 dark energy south would be the particle
00:02:36 --> 00:02:39 that pushes outwards creating negative
00:02:39 --> 00:02:41 pressure and expanding the universe.
00:02:41 --> 00:02:43 Thoughts. Now, that's his question. But
00:02:43 --> 00:02:45 he says, "By the way, Martin's joke
00:02:45 --> 00:02:48 about the Ganab Gibb being a lost BG
00:02:48 --> 00:02:50 brother made me laugh out loud for a
00:02:50 --> 00:02:52 couple of minutes." That's Daryl from
00:02:52 --> 00:02:54 South Australia. Yeah, I thought it was
00:02:54 --> 00:02:56 funny, too. And that's the first time
00:02:56 --> 00:02:58 Martin's ever been funny. But, um, no,
00:02:58 --> 00:03:00 we It was a good one. It was a very good
00:03:00 --> 00:03:04 one. Um, yes. So, um, this is an
00:03:04 --> 00:03:06 interesting theory. as a dark matter
00:03:06 --> 00:03:10 south pole dark energy north pole
00:03:10 --> 00:03:12 opposites attract type of scenario I
00:03:12 --> 00:03:16 don't know what do you think so the the
00:03:16 --> 00:03:19 issue yes uh it's a nice thought because
00:03:19 --> 00:03:21 the you know we naturally think along
00:03:21 --> 00:03:23 those lines when we recognize that one
00:03:24 --> 00:03:27 of these forces entities
00:03:28 --> 00:03:30 pull stuff together and the other pushes
00:03:30 --> 00:03:32 it apart
00:03:32 --> 00:03:33 um
00:03:33 --> 00:03:35 And
00:03:36 --> 00:03:38 in in many ways that's the crux of the
00:03:38 --> 00:03:41 matter because the the two of them are
00:03:41 --> 00:03:44 fundamentally different in their uh in
00:03:44 --> 00:03:46 their effect on the universe. So dark
00:03:46 --> 00:03:50 energy which comes as a man which is
00:03:50 --> 00:03:53 manifested to us in the accelerated
00:03:53 --> 00:03:55 expansion of the universe that's an
00:03:55 --> 00:03:58 energy of space itself and to the best
00:03:58 --> 00:04:01 of our ability uh to determine these
00:04:01 --> 00:04:04 things it is isotropic uh in other words
00:04:04 --> 00:04:07 it's the same in all directions. Now
00:04:07 --> 00:04:09 some people have questioned that
00:04:10 --> 00:04:13 >> uh s suggesting that maybe you know for
00:04:13 --> 00:04:16 all we are looking at a big chunk of the
00:04:16 --> 00:04:18 universe with a horizon of 13.8 8
00:04:18 --> 00:04:21 billion light years. Um it may be that
00:04:21 --> 00:04:23 that's just a small part of the universe
00:04:23 --> 00:04:25 and there are other bits where where you
00:04:25 --> 00:04:27 know the
00:04:27 --> 00:04:29 the acceleration is not sorry the
00:04:29 --> 00:04:32 expansion is not accelerating uh and the
00:04:32 --> 00:04:37 two sort of even out. Um that's that's
00:04:37 --> 00:04:39 a a a caveat that we can't really deal
00:04:39 --> 00:04:41 with because we've no idea what happens
00:04:41 --> 00:04:43 beyond the little bubble of the universe
00:04:43 --> 00:04:45 that we can observe. Yeah. And certainly
00:04:45 --> 00:04:48 it's true within that bubble the
00:04:48 --> 00:04:50 acceleration is basically this or the
00:04:50 --> 00:04:53 accelerated sorry the accelerated
00:04:53 --> 00:04:56 expansion is basically the same in all
00:04:56 --> 00:04:58 directions. So it's a property of space
00:04:58 --> 00:05:01 itself. It's a fundamental property. Um
00:05:01 --> 00:05:03 whereas dark matter yes that's got
00:05:03 --> 00:05:05 gravitation
00:05:05 --> 00:05:08 um and pulls stuff in. It's definitely
00:05:08 --> 00:05:13 clumpy. Uh it it it actually um well it
00:05:13 --> 00:05:15 follows the the the visible matter. That
00:05:15 --> 00:05:17 was the way it was thought to be when we
00:05:17 --> 00:05:19 first started thinking about dark
00:05:19 --> 00:05:20 matter. But now we think it's probably
00:05:20 --> 00:05:21 the other way around that the visible
00:05:21 --> 00:05:24 matter is visible because dark matter
00:05:24 --> 00:05:27 acted as a kind of scaffolding uh in the
00:05:27 --> 00:05:29 early universe for uh the gravitational
00:05:30 --> 00:05:33 pull of dark matter uh in order to bring
00:05:33 --> 00:05:34 the clouds of hydrogen together,
00:05:34 --> 00:05:36 compress them and make them turn into
00:05:36 --> 00:05:40 stars. So um that's why dark matter and
00:05:40 --> 00:05:42 normal matter stick together but they do
00:05:42 --> 00:05:45 stick together. Uh and when you you know
00:05:45 --> 00:05:47 when you observe the universe on the
00:05:47 --> 00:05:50 larger scales we can see um by for
00:05:50 --> 00:05:53 example gravitational lensing uh we can
00:05:53 --> 00:05:58 see that the uh the the um dark matter
00:05:58 --> 00:06:00 definitely follows the visible matter.
00:06:00 --> 00:06:03 So there will be places where uh there's
00:06:03 --> 00:06:05 hardly any visible matter and there's
00:06:05 --> 00:06:08 hardly any dark matter whereas with the
00:06:08 --> 00:06:10 dark energy it's everywhere
00:06:10 --> 00:06:12 >> and so there's there are fundamental
00:06:12 --> 00:06:14 differences between them and I suspect
00:06:14 --> 00:06:16 in the end you know if we were having
00:06:16 --> 00:06:21 this conversation in 20 or 30 years time
00:06:21 --> 00:06:24 we probably will be actually but anyway
00:06:24 --> 00:06:26 um when we look back on this we we might
00:06:26 --> 00:06:30 have realized that uh the dark uh energy
00:06:30 --> 00:06:33 is a bzon. It's a it's a force particle.
00:06:33 --> 00:06:36 Uh whereas dark matter is some sort of
00:06:36 --> 00:06:38 matter particle made of quarks and
00:06:38 --> 00:06:40 things of that sort. So there probably
00:06:40 --> 00:06:43 fundamental differences rather than just
00:06:43 --> 00:06:46 that sort of the idea that they might be
00:06:46 --> 00:06:47 the same thing but with a different
00:06:47 --> 00:06:48 polarity.
00:06:48 --> 00:06:48 >> Yeah.
00:06:48 --> 00:06:51 >> Um I I I don't think the evidence
00:06:51 --> 00:06:53 supports that. I suppose we could say
00:06:53 --> 00:06:57 Daryl's fallen for the naming error uh
00:06:57 --> 00:07:00 of of these two things because um we
00:07:00 --> 00:07:02 we've said all along that dark energy is
00:07:02 --> 00:07:06 poorly named. It's it's not really
00:07:06 --> 00:07:09 the right thing to call it. Well, well,
00:07:09 --> 00:07:11 neither of them are really, you know,
00:07:11 --> 00:07:14 they're invisible would have been far
00:07:14 --> 00:07:17 better, but dark. It was actually Fritz
00:07:17 --> 00:07:21 Vicki back in 1933 who labeled um this
00:07:21 --> 00:07:23 stuff dark matter. He didn't what it was
00:07:23 --> 00:07:24 and he said there must be something
00:07:24 --> 00:07:26 there which he was calling dark matter
00:07:26 --> 00:07:29 that um that's providing enough of a
00:07:30 --> 00:07:31 gravitational attraction to stop
00:07:31 --> 00:07:33 clusters of galaxies from dispersing
00:07:33 --> 00:07:34 altogether.
00:07:34 --> 00:07:37 >> Yeah. Interesting. Um they'll figure it
00:07:37 --> 00:07:40 out one day, but um for now it it
00:07:40 --> 00:07:42 remains a mystery. But that there's got
00:07:42 --> 00:07:44 to be something in that connection
00:07:44 --> 00:07:48 between real matter and dark matter
00:07:48 --> 00:07:51 plumping. Like if you go somewhere there
00:07:51 --> 00:07:53 isn't much matter, there isn't much dark
00:07:53 --> 00:07:56 matter. So there's got to be some
00:07:56 --> 00:07:57 connection there that
00:07:57 --> 00:07:58 >> there is. That's right.
00:07:58 --> 00:07:59 >> That will that will give us the answer
00:07:59 --> 00:08:01 one day if we can figure out what the
00:08:01 --> 00:08:03 connection is.
00:08:03 --> 00:08:05 >> Yeah. Well, the connection is gravity
00:08:05 --> 00:08:07 and um it's the only um
00:08:07 --> 00:08:09 >> Well, we haven't figured that out
00:08:09 --> 00:08:09 either.
00:08:09 --> 00:08:11 >> No, that's right. We basically we we
00:08:11 --> 00:08:13 know how it behaves. We know very
00:08:13 --> 00:08:14 accurately how it behaves, but we don't
00:08:14 --> 00:08:17 know what it is.
00:08:17 --> 00:08:17 >> Yeah,
00:08:17 --> 00:08:19 >> it is indeed a mystery, Darl. Uh but
00:08:19 --> 00:08:23 coming up with an idea always is um a
00:08:23 --> 00:08:25 good way to get people thinking and
00:08:25 --> 00:08:28 maybe maybe somewhere in the dark
00:08:28 --> 00:08:29 reaches of the internet someone will
00:08:29 --> 00:08:31 hear this and go, "Hang on, Daryl's on
00:08:31 --> 00:08:33 to something." And then he'll go to his
00:08:33 --> 00:08:36 Wikipedia or his uh encyclopedia
00:08:36 --> 00:08:39 Bratannica or his Funkin Wagnoff, flick
00:08:39 --> 00:08:41 a few pages and go,
00:08:41 --> 00:08:43 I've got it figured out thanks to
00:08:43 --> 00:08:45 Daryl's question on space nuts. So, you
00:08:45 --> 00:08:48 know, there are no dumb questions in
00:08:48 --> 00:08:49 astronomy, are there, Fred?
00:08:49 --> 00:08:52 >> No, that's absolutely right. There's
00:08:52 --> 00:08:55 just dumb answers from the likes of me.
00:08:55 --> 00:08:57 >> Thanks, Daryl. Great to hear from you.
00:08:57 --> 00:09:00 Our next question comes from the fjords
00:09:00 --> 00:09:05 of Norway. Uh and um this uh question
00:09:05 --> 00:09:07 goes by the name of someone will
00:09:07 --> 00:09:09 recognize this Slatty Bfast. Uh
00:09:10 --> 00:09:11 listening from the fields of Norway last
00:09:11 --> 00:09:13 week. Someone asked the question about
00:09:13 --> 00:09:15 viewing the birth of the sun and Fred
00:09:15 --> 00:09:19 answered with the hypothetical mirror in
00:09:19 --> 00:09:22 space. My question is if we calculated
00:09:22 --> 00:09:25 the exact location in space for the sun
00:09:25 --> 00:09:28 4.6 six billion years ago and pointed a
00:09:28 --> 00:09:30 telescope at those coordinate uh
00:09:30 --> 00:09:36 coordinates, would we see anything?
00:09:36 --> 00:09:38 >> Cuz slatty Bfast won an award, didn't
00:09:38 --> 00:09:41 he, for the fields of Norway? So that
00:09:41 --> 00:09:44 >> Oh, that's right. That's right. Yes,
00:09:44 --> 00:09:46 that wasn't because he he designed them
00:09:46 --> 00:09:47 or
00:09:47 --> 00:09:49 >> designed them. Yes, he made he made
00:09:49 --> 00:09:50 fjords.
00:09:50 --> 00:09:52 >> That's right. That was what Zan Bartfast
00:09:52 --> 00:09:55 was famous for. One of my favorite
00:09:55 --> 00:09:56 Douglas Adams characters.
00:09:56 --> 00:09:58 >> Oh, yeah. Brilliant. I think the moment
00:09:58 --> 00:10:01 where he's forced to say his name is one
00:10:01 --> 00:10:04 of the the the funniest moments I've
00:10:04 --> 00:10:06 ever experienced
00:10:06 --> 00:10:08 cuz first time I ever listened to it. I
00:10:08 --> 00:10:12 listened to the audio version. That just
00:10:12 --> 00:10:14 caught me so beautifully. I just
00:10:14 --> 00:10:17 couldn't stop cackling.
00:10:17 --> 00:10:20 >> Very No, it's it's epic. Epic stuff. One
00:10:20 --> 00:10:22 of the all-time greats in science
00:10:22 --> 00:10:24 fiction. Absolutely. Yes.
00:10:24 --> 00:10:27 >> Yeah. Um anyway, the answer to Slatty
00:10:27 --> 00:10:31 Bfast's question is no. So, um do you
00:10:31 --> 00:10:33 want to keep going?
00:10:33 --> 00:10:35 >> Well, I mean, he he's basically saying
00:10:35 --> 00:10:37 we So, you're saying we would not see
00:10:37 --> 00:10:39 anything if we could figure out where
00:10:39 --> 00:10:41 the sun was 4.6 billion years ago and
00:10:41 --> 00:10:43 then pointed a telescope at it.
00:10:43 --> 00:10:46 >> Yeah. Because um first of all, the sun
00:10:46 --> 00:10:47 isn't there anymore.
00:10:47 --> 00:10:49 >> No, I know where it is.
00:10:49 --> 00:10:52 >> Yes. The odds are there.
00:10:52 --> 00:10:56 >> That that point uh you Let me see which
00:10:56 --> 00:10:57 way you're pointing.
00:10:57 --> 00:10:58 >> I'm pointing that way.
00:10:58 --> 00:11:00 >> That way. That's good. That's probably
00:11:00 --> 00:11:02 correct, too. In fact, it's behind me,
00:11:02 --> 00:11:07 too. It's to my It's to my right rear.
00:11:07 --> 00:11:07 >> That way.
00:11:08 --> 00:11:09 >> All right. Okay. At the moment. That's a
00:11:10 --> 00:11:11 bit intimate, isn't it? Anyway, never
00:11:11 --> 00:11:15 mind. Um the uh the sun is certainly not
00:11:15 --> 00:11:17 shining out of that particular part of
00:11:17 --> 00:11:20 me at the moment, but it's it's in that
00:11:20 --> 00:11:23 kind of direction.
00:11:23 --> 00:11:25 >> It's what all your fans think though,
00:11:25 --> 00:11:25 isn't it?
00:11:26 --> 00:11:29 >> They don't. Uh I don't even have any I
00:11:29 --> 00:11:32 don't get fan mail. I get abuse.
00:11:32 --> 00:11:33 >> Well,
00:11:33 --> 00:11:36 uh anyway, um notwithstanding all that,
00:11:36 --> 00:11:38 what was the question again? Yes. If you
00:11:38 --> 00:11:40 could work out where the sun was 4.6 six
00:11:40 --> 00:11:43 billion years ago and point a telescope
00:11:43 --> 00:11:46 at it, you wouldn't see anything because
00:11:46 --> 00:11:50 the the point where the sun was formed.
00:11:50 --> 00:11:53 Um, and it it it will be only a few at
00:11:54 --> 00:11:58 most 100 million light years away. Uh,
00:11:58 --> 00:12:00 so yeah, you've got to look back time,
00:12:00 --> 00:12:02 but you've got to look back time. It's
00:12:02 --> 00:12:04 probably less than 100 million years.
00:12:04 --> 00:12:07 Uh, and the sun 100 million years ago
00:12:07 --> 00:12:09 was a lot like what it is now. It's
00:12:09 --> 00:12:11 slightly hotter uh and a few other
00:12:11 --> 00:12:13 things that were going on at the time,
00:12:13 --> 00:12:15 but not much different. But the fact is
00:12:15 --> 00:12:20 it's not there, it's here. Um so even
00:12:20 --> 00:12:23 as I think I said uh in that thought
00:12:23 --> 00:12:25 experiment, you'd have to have a mirror
00:12:25 --> 00:12:29 uh something like 2.3 billion light
00:12:29 --> 00:12:31 years away
00:12:31 --> 00:12:33 uh which is going to take you quite a
00:12:33 --> 00:12:36 lot of time to put in place anyway. But
00:12:36 --> 00:12:39 if that mirror was looking back to
00:12:39 --> 00:12:40 wherever the sun was formed, and we
00:12:40 --> 00:12:43 don't know where that was. Uh we know
00:12:43 --> 00:12:45 it's within the present vicinity of the
00:12:45 --> 00:12:47 sun because stars don't move that fast.
00:12:47 --> 00:12:50 Uh anyway, um you you have this mirror
00:12:50 --> 00:12:54 and you capture a reflection of the sun
00:12:54 --> 00:12:57 being born. Uh that thought experiment I
00:12:57 --> 00:13:00 think would work, but just um looking at
00:13:00 --> 00:13:04 where the sun was when it was born isn't
00:13:04 --> 00:13:06 going to tell you very much. There's got
00:13:06 --> 00:13:08 to be something there though, right?
00:13:08 --> 00:13:10 >> Well, there be Yeah. Probably other
00:13:10 --> 00:13:12 stars and things like that, you know.
00:13:12 --> 00:13:13 It's just part of the the solar
00:13:13 --> 00:13:15 neighborhood. Yeah.
00:13:15 --> 00:13:18 >> Yeah. Our our son, I suspect, came from,
00:13:18 --> 00:13:21 you know, a pretty rough neighborhood
00:13:21 --> 00:13:23 and that's why it left. It uh inherited
00:13:24 --> 00:13:26 money and managed to managed to get
00:13:26 --> 00:13:27 away.
00:13:28 --> 00:13:29 >> Yeah. But then it discovered drugs,
00:13:29 --> 00:13:30 didn't it? That's
00:13:30 --> 00:13:32 >> Yeah. Well, that's that's what happened.
00:13:32 --> 00:13:35 Yes. And and then we turned up and um
00:13:35 --> 00:13:36 Yeah.
00:13:36 --> 00:13:39 >> Well, hell broke loose. Yes. Uh but
00:13:39 --> 00:13:41 there'd be nothing to see there. Nothing
00:13:41 --> 00:13:43 to see there. No.
00:13:43 --> 00:13:44 >> Nothing that's really of any interest.
00:13:44 --> 00:13:45 Just other stars.
00:13:45 --> 00:13:46 >> Yeah.
00:13:46 --> 00:13:48 >> Yeah. Although we're still looking for
00:13:48 --> 00:13:50 Earth's siblings. Uh sorry, the sun's
00:13:50 --> 00:13:51 siblings. That's
00:13:52 --> 00:13:52 >> That's right.
00:13:52 --> 00:13:54 >> Because there there would be some, but
00:13:54 --> 00:13:55 they wouldn't be there either, would
00:13:55 --> 00:13:59 they? Well, that you know that the stars
00:13:59 --> 00:14:01 and that I'm sorry, the stars that were
00:14:01 --> 00:14:04 born alongside the sun in the same cloud
00:14:04 --> 00:14:06 of gas and dust uh are probably not that
00:14:06 --> 00:14:13 far away. Uh but um they
00:14:13 --> 00:14:14 yeah
00:14:14 --> 00:14:17 100 Yeah, 100 100 million light years I
00:14:17 --> 00:14:19 mentioned before. It's probably much
00:14:19 --> 00:14:21 much less than that. I don't know quite
00:14:21 --> 00:14:25 why I thought of that, but anyway,
00:14:25 --> 00:14:26 because the center of our galaxy is only
00:14:26 --> 00:14:30 25 light years away. Uh, so um I
00:14:30 --> 00:14:33 probably meant 100 light years as
00:14:33 --> 00:14:36 when I said 100 million. Um,
00:14:36 --> 00:14:38 something's going wrong with this
00:14:38 --> 00:14:39 program today. I'm not quite sure. Well,
00:14:39 --> 00:14:39 we
00:14:40 --> 00:14:42 >> It's 100 It's a 600.
00:14:42 --> 00:14:44 >> That's what it is. That's what it is.
00:14:44 --> 00:14:46 There's a there's a a gap in spaceime
00:14:46 --> 00:14:49 has opened up uh which I'm floundering
00:14:49 --> 00:14:51 in at the moment. Yeah. So, you know,
00:14:51 --> 00:14:54 you might it's it's not gone very far.
00:14:54 --> 00:14:56 Uh that's what I'm saying. The siblings
00:14:56 --> 00:14:59 from from the sun in the born in the
00:14:59 --> 00:15:01 same gas cloud from the sun are probably
00:15:01 --> 00:15:03 within they might even be within the
00:15:03 --> 00:15:06 nearest 100 million sorry 100 light
00:15:06 --> 00:15:11 years not million light years. Um so uh
00:15:11 --> 00:15:16 and that's why we can use very high
00:15:16 --> 00:15:19 resolution instruments, ones that uh
00:15:19 --> 00:15:21 really analyze the spectrum of a star in
00:15:21 --> 00:15:23 great detail but need the star to be
00:15:23 --> 00:15:25 relatively bright. That's why we can use
00:15:25 --> 00:15:27 that technology with a real hope of
00:15:27 --> 00:15:29 finding the solar siblings because it's
00:15:29 --> 00:15:32 by analyzing the the spectrum the
00:15:32 --> 00:15:34 chemical composition of a star uh in
00:15:34 --> 00:15:37 very great detail. That's how we would
00:15:37 --> 00:15:39 identify that a star had exactly the
00:15:40 --> 00:15:42 same chemical composition as the sun and
00:15:42 --> 00:15:44 could be regarded as likely to be a
00:15:44 --> 00:15:46 solar sibling.
00:15:46 --> 00:15:50 >> Okay. We may one day find one of them,
00:15:50 --> 00:15:52 but who knows? Yeah,
00:15:52 --> 00:15:55 >> we'll see. Uh, and thank you Slatty
00:15:55 --> 00:15:57 Bartfast. Um, whatever your real name
00:15:57 --> 00:15:59 is. That maybe that's it. Um,
00:15:59 --> 00:16:00 >> could be. Could be.
00:16:00 --> 00:16:02 >> Thanks. Thanks for the question and and
00:16:02 --> 00:16:03 thank you for sending me the Babel fish
00:16:03 --> 00:16:06 so I could read the question. That was
00:16:06 --> 00:16:08 that was a good idea. Very very good
00:16:08 --> 00:16:11 idea. This is Space Nuts. Andrew Dunley
00:16:11 --> 00:16:14 here with Professor Fred Watson.
00:16:14 --> 00:16:16 Let's take a break from the show to tell
00:16:16 --> 00:16:19 you about our sponsor, NordVPN.
00:16:19 --> 00:16:21 Now, if you've ever felt like your
00:16:21 --> 00:16:23 online privacy is slipping through the
00:16:23 --> 00:16:25 cracks, then you're not alone. Hackers,
00:16:26 --> 00:16:27 scammers, harvesters, they're all out
00:16:27 --> 00:16:29 there trying to get your private info.
00:16:29 --> 00:16:31 Whether that's your passwords or your
00:16:31 --> 00:16:34 personal details to sell on the dark web
00:16:34 --> 00:16:37 or to use themselves to access your bank
00:16:37 --> 00:16:39 accounts, credit card details, and who
00:16:39 --> 00:16:41 knows what else. But you can protect
00:16:41 --> 00:16:44 yourself with NordVPN.
00:16:44 --> 00:16:47 You can take control at home or or more
00:16:47 --> 00:16:49 importantly when you're out in public
00:16:49 --> 00:16:53 using free Wi-Fi. Right now uh using the
00:16:53 --> 00:16:56 exclusive Space Nuts offer, you can
00:16:56 --> 00:17:00 receive four extra months for free on a
00:17:00 --> 00:17:02 NordVPN.com
00:17:02 --> 00:17:05 plan. NordVPN encrypts your internet
00:17:05 --> 00:17:07 connection, hides your IP address, and
00:17:07 --> 00:17:11 offers access to over 7 servers
00:17:11 --> 00:17:13 around the world. Plus, with features
00:17:14 --> 00:17:17 like threat protection pro, meshet,
00:17:17 --> 00:17:20 ultra fast speeds via Nord links, your
00:17:20 --> 00:17:23 digital life stays private and
00:17:23 --> 00:17:26 efficient. So, don't miss out. Visit
00:17:26 --> 00:17:30 nordvpn.com/spacenuts
00:17:30 --> 00:17:32 and enter the code spacenuts to claim
00:17:32 --> 00:17:35 this deal. Remember, there's a 30-day
00:17:35 --> 00:17:37 money back guarantee, so it's riskfree
00:17:37 --> 00:17:40 to try. Stay safe, stay private, and
00:17:40 --> 00:17:43 browse with confidence. That's
00:17:43 --> 00:17:46 nordvpn.com/spacenuts
00:17:46 --> 00:17:49 and use the code word spacen nuts.
00:17:49 --> 00:17:54 nordvpn.com/spacenuts.
00:17:54 --> 00:17:56 >> Okay, we've had a problem here.
00:17:56 --> 00:17:58 >> This is Houston. Say again, please.
00:17:58 --> 00:17:59 >> Houston, we had a problem. We had a
00:17:59 --> 00:18:00 main.
00:18:00 --> 00:18:03 >> Roger. Main. Okay, stand by 13. We're
00:18:03 --> 00:18:04 looking at it.
00:18:04 --> 00:18:06 >> Space nuts. You know, that moment where
00:18:06 --> 00:18:09 they realized they had a problem on um
00:18:09 --> 00:18:12 Apollo 13 sounded much better in the
00:18:12 --> 00:18:14 movie.
00:18:14 --> 00:18:17 >> It just um Yeah,
00:18:18 --> 00:18:21 >> you bro you broke up exactly as you were
00:18:21 --> 00:18:21 saying.
00:18:21 --> 00:18:23 >> I noticed that and I was going to keep
00:18:23 --> 00:18:25 talking until you came back, but um
00:18:25 --> 00:18:26 >> tell me what you said.
00:18:26 --> 00:18:29 >> I said that that moment where Apollo 13
00:18:29 --> 00:18:32 realized they had that problem sounded
00:18:32 --> 00:18:35 much better in the movie.
00:18:35 --> 00:18:35 Yeah.
00:18:35 --> 00:18:37 >> Wasn't nearly as dramatic in real life,
00:18:38 --> 00:18:39 was it?
00:18:39 --> 00:18:39 >> Well, that's
00:18:39 --> 00:18:41 >> Well, it was dramatic, but the way they
00:18:41 --> 00:18:41 announced it.
00:18:42 --> 00:18:42 >> Absolutely.
00:18:42 --> 00:18:44 >> Yeah. They they basically just said,
00:18:44 --> 00:18:47 "Yeah, this button didn't work."
00:18:47 --> 00:18:48 >> More or less.
00:18:48 --> 00:18:49 >> Um,
00:18:49 --> 00:18:51 >> yeah. Epic stuff. I mean, it still gives
00:18:51 --> 00:18:54 me tingles. Does Apollo 13.
00:18:54 --> 00:18:57 >> Absolutely. Yeah. Now, Fred, let's move
00:18:57 --> 00:19:00 on to our third question. This one comes
00:19:00 --> 00:19:02 from Bejorn.
00:19:02 --> 00:19:06 >> Good evening, Fred. And Andrew, I have
00:19:06 --> 00:19:10 to thank you for a fantastic podcast. My
00:19:10 --> 00:19:13 first choice every evening
00:19:13 --> 00:19:17 among lots of interesting stuff. It's
00:19:17 --> 00:19:20 the first one I choose.
00:19:20 --> 00:19:22 Uh it's regarding the question you had
00:19:22 --> 00:19:25 about temperature of black holes.
00:19:25 --> 00:19:30 I must ask you to clarify.
00:19:30 --> 00:19:33 If material accretes
00:19:33 --> 00:19:35 close to the end horizon, it's millions
00:19:36 --> 00:19:38 of degrees hot.
00:19:38 --> 00:19:41 If I follow the material spiraling
00:19:41 --> 00:19:44 inwards, it does not suddenly become
00:19:44 --> 00:19:46 cold when it enters the event horizon.
00:19:46 --> 00:19:48 Right?
00:19:48 --> 00:19:51 It's still extremely hot, maybe even
00:19:51 --> 00:19:53 hotter, even if it's supposedly hard to
00:19:53 --> 00:19:54 measure.
00:19:54 --> 00:19:57 because it's hard to get a thermometer
00:19:57 --> 00:20:00 in there and have a reference.
00:20:00 --> 00:20:02 But it extremely hot.
00:20:02 --> 00:20:05 That seems cold to an outside observer
00:20:05 --> 00:20:09 because it does not radiate anything.
00:20:09 --> 00:20:13 But maybe it could be clarified somehow.
00:20:13 --> 00:20:15 It's not magic that it suddenly gets
00:20:15 --> 00:20:18 cold. It just
00:20:18 --> 00:20:21 stops emitting. Right.
00:20:22 --> 00:20:24 Take care. It's Bjon from Goththingberg.
00:20:24 --> 00:20:26 I love your show.
00:20:26 --> 00:20:28 >> Thank you, Bjorn. That Babel Fish is
00:20:28 --> 00:20:29 working well because his English was
00:20:29 --> 00:20:31 excellent.
00:20:31 --> 00:20:33 >> He lives in a nice place as well.
00:20:33 --> 00:20:35 Goththingberg's got a very nice city
00:20:35 --> 00:20:37 center with a lovely opera house.
00:20:37 --> 00:20:39 >> Yeah, I haven't been there. In fact, I
00:20:39 --> 00:20:42 haven't been to Sweden yet, but um yeah,
00:20:42 --> 00:20:44 it's it's on the wish list. So, we'll
00:20:44 --> 00:20:45 we'll see how we go.
00:20:45 --> 00:20:47 >> It's great. Now, he's referring to a
00:20:47 --> 00:20:49 question that came from Casey in
00:20:49 --> 00:20:51 Colorado when she was asking about the
00:20:51 --> 00:20:54 temperature of a of a black hole. Uh, so
00:20:54 --> 00:20:58 he's basically kind of saying, "Look,
00:20:58 --> 00:20:59 I understand what you were saying when
00:20:59 --> 00:21:01 you answered Casey, but now everyone
00:21:01 --> 00:21:04 thinks they're cold when they're
00:21:04 --> 00:21:05 probably not cold. They're just not
00:21:05 --> 00:21:07 emitting anything."
00:21:07 --> 00:21:08 Is that right?
00:21:08 --> 00:21:12 >> Yeah, that's that's right. They're cold
00:21:12 --> 00:21:14 because they're not emitting anything.
00:21:14 --> 00:21:18 But uh but uh Bjorn's right that you
00:21:18 --> 00:21:21 know the temperature of the accretion
00:21:21 --> 00:21:23 disc and and probably the way to look at
00:21:23 --> 00:21:24 it is the temperature of the event
00:21:24 --> 00:21:27 horizon is millions of degrees because
00:21:27 --> 00:21:29 that's where all this stuff is is
00:21:30 --> 00:21:33 circulating at high speed uh and with
00:21:33 --> 00:21:35 huge amounts of energy and emitting
00:21:35 --> 00:21:38 X-rays. um it disappears over the event
00:21:38 --> 00:21:42 horizon uh at very high temperature and
00:21:42 --> 00:21:45 presumably within the event horizon it's
00:21:45 --> 00:21:48 still got that high temperature but then
00:21:48 --> 00:21:52 it hits the black hole it's sucked in uh
00:21:52 --> 00:21:54 and if you could measure the temperature
00:21:54 --> 00:21:57 of the black hole itself you'd find it
00:21:57 --> 00:21:59 was virtually absolute zero very very
00:22:00 --> 00:22:01 small temperature
00:22:01 --> 00:22:02 >> okay
00:22:02 --> 00:22:04 >> um because it's not emitting anything's
00:22:04 --> 00:22:09 going in um and it is it is hard to
00:22:09 --> 00:22:11 imagine and Bjorn mentioned magic and
00:22:11 --> 00:22:14 that's almost what it is um you know
00:22:14 --> 00:22:15 stuff that's going in at very high
00:22:15 --> 00:22:17 temperature but if you could measure the
00:22:17 --> 00:22:19 black hole itself supposing it stopped
00:22:19 --> 00:22:21 accreating material and you could then
00:22:21 --> 00:22:23 measure its temperature it would be
00:22:23 --> 00:22:25 virtually zero
00:22:25 --> 00:22:29 >> well well they are so complicated though
00:22:29 --> 00:22:31 aren't they? I mean, we we we we're
00:22:31 --> 00:22:35 still learning a lot about um black
00:22:35 --> 00:22:37 holes and and we we're starting to image
00:22:38 --> 00:22:39 a few of them. We've got a couple of
00:22:39 --> 00:22:43 good pickies now, but uh we we
00:22:43 --> 00:22:46 they are still mesmerizing and
00:22:46 --> 00:22:48 mystifying because until dark matter
00:22:48 --> 00:22:50 came along, um we got more questions
00:22:50 --> 00:22:52 about black holes than anything else.
00:22:52 --> 00:22:54 they they are the thing that people want
00:22:54 --> 00:22:57 us to unravel in terms of understanding.
00:22:57 --> 00:22:59 But um we're I think we're a long way
00:22:59 --> 00:23:01 away from that at the moment, aren't we?
00:23:01 --> 00:23:05 >> Um I actually I think you know that we
00:23:05 --> 00:23:09 know a lot about black holes. Um
00:23:09 --> 00:23:12 considering that 60 years ago nobody
00:23:12 --> 00:23:13 believed they existed.
00:23:13 --> 00:23:17 >> Yeah. Well, the point um and um we've
00:23:17 --> 00:23:19 observed them. We've actually observed
00:23:19 --> 00:23:23 the uh radiation coming from the the the
00:23:23 --> 00:23:25 accretion disc, the region around the
00:23:25 --> 00:23:27 event horizon. We've we've observed the
00:23:27 --> 00:23:29 effectively the shadow of the event
00:23:29 --> 00:23:32 horizon of several black holes now. Uh
00:23:32 --> 00:23:34 and even detected the polarization of
00:23:34 --> 00:23:36 the material that's being sucked into
00:23:36 --> 00:23:38 it. And this is extraordinary stuff.
00:23:38 --> 00:23:40 These are measurements that really only
00:23:40 --> 00:23:41 a few years ago would have been thought
00:23:41 --> 00:23:43 to be impossible, but we're I think
00:23:44 --> 00:23:47 doing it rather well. So, we're still
00:23:47 --> 00:23:49 learning about black holes. They are and
00:23:49 --> 00:23:51 that that's the reason why they're so
00:23:51 --> 00:23:52 fascinating is that they are completely
00:23:52 --> 00:23:54 counterintuitive.
00:23:54 --> 00:23:55 How do you have something that's
00:23:55 --> 00:23:57 simultaneously at zero and a million
00:23:57 --> 00:24:01 degrees and that's what you've got? Uh
00:24:01 --> 00:24:06 so, yeah. So, it's um it it yeah, there
00:24:06 --> 00:24:08 still very very interesting object.
00:24:08 --> 00:24:12 >> But, um back to Bjorn's question, the
00:24:12 --> 00:24:15 temperature is
00:24:15 --> 00:24:18 zero absolute zero or thereabouts
00:24:18 --> 00:24:21 because of the fact that it doesn't
00:24:21 --> 00:24:23 >> it doesn't radiate anything. Yeah.
00:24:23 --> 00:24:25 Exactly. So, so the the way to imagine
00:24:25 --> 00:24:27 it I think and this probably puts it
00:24:27 --> 00:24:30 more succinctly. Yes. While while it's
00:24:30 --> 00:24:32 accreting, you can't you can't see the
00:24:32 --> 00:24:33 black hole because it's surrounded by
00:24:33 --> 00:24:36 this hot material at very high
00:24:36 --> 00:24:38 temperature that's being swallowed into
00:24:38 --> 00:24:40 it. But if there was if that supply of
00:24:40 --> 00:24:42 gas ran out and the black hole stopped
00:24:42 --> 00:24:44 accreting then you would and you could
00:24:44 --> 00:24:47 measure its temperature then um it would
00:24:47 --> 00:24:49 be zero effectively be absolute zero a
00:24:49 --> 00:24:51 little bit above but not very much.
00:24:51 --> 00:24:54 >> Okay there you go Bjorn and I'm looking
00:24:54 --> 00:24:57 at uh photographs of Gottenberg. It's it
00:24:57 --> 00:25:00 is an absolute beauty of a city isn't
00:25:00 --> 00:25:03 it? What a lovely part of the world. So
00:25:03 --> 00:25:08 uh yeah, very lucky. Nice tra
00:25:08 --> 00:25:10 um thanks buen. Great to hear from you
00:25:10 --> 00:25:14 uh in Sweden.
00:25:14 --> 00:25:16 >> Okay, we checked all four systems and
00:25:16 --> 00:25:17 with the go
00:25:17 --> 00:25:18 >> space nets
00:25:18 --> 00:25:21 >> and believe it or not, our next question
00:25:21 --> 00:25:24 comes from Sweden. Uh does the expansion
00:25:24 --> 00:25:27 of space mean that the universe gains
00:25:27 --> 00:25:30 more meters or are the meters becoming
00:25:30 --> 00:25:33 longer? related to this. Is it space
00:25:33 --> 00:25:36 only that is expanding or is it space
00:25:36 --> 00:25:40 time? If so, what's happening uh to the
00:25:40 --> 00:25:43 time part of it? Is time expanding too?
00:25:43 --> 00:25:45 What would that mean? Uh thanks for a
00:25:46 --> 00:25:49 most interesting podcast, Peter from
00:25:49 --> 00:25:50 uh I'm going to pronounce this
00:25:50 --> 00:25:55 incorrectly. Falloon in Sweden.
00:25:55 --> 00:25:57 >> So yeah, hopefully I got that right.
00:25:57 --> 00:25:59 think my babel my babel fish can't
00:25:59 --> 00:26:02 translate back into Swed Swedish.
00:26:02 --> 00:26:04 >> Well, if you put it the other way
00:26:04 --> 00:26:04 around,
00:26:04 --> 00:26:06 >> got to put in the other ear.
00:26:06 --> 00:26:08 >> Yeah, that's right.
00:26:08 --> 00:26:09 >> That'll do it.
00:26:09 --> 00:26:13 >> Um, so, uh, yes, uh, that's a great
00:26:13 --> 00:26:16 question. And so um my view you know the
00:26:16 --> 00:26:21 intuitive view uh which is based on
00:26:21 --> 00:26:23 a few years of thinking about this kind
00:26:23 --> 00:26:26 of thing. Um the me the meters are
00:26:26 --> 00:26:31 becoming longer. Um and that's sort of
00:26:31 --> 00:26:32 illustrated by the fact that the
00:26:32 --> 00:26:34 wavelength of radiation is getting
00:26:34 --> 00:26:37 longer. Uh you know that radiation had a
00:26:37 --> 00:26:39 particular wavelength when it was
00:26:39 --> 00:26:42 emitted. Uh um and as the universe has
00:26:42 --> 00:26:44 expanded, whatever it's coming from,
00:26:44 --> 00:26:46 whether it's a distant galaxy or a
00:26:46 --> 00:26:48 quazar or whatever, uh as the universe
00:26:48 --> 00:26:50 has expanded, that radiation has been
00:26:50 --> 00:26:52 stretched, which means that the meat has
00:26:52 --> 00:26:54 been stretched because the frequency
00:26:54 --> 00:26:59 remains the same. Uh
00:27:00 --> 00:27:02 except when you observe it
00:27:02 --> 00:27:05 >> uh from our vantage point in the depths
00:27:06 --> 00:27:07 of the universe.
00:27:07 --> 00:27:10 >> Yeah. Forget about the frequency.
00:27:10 --> 00:27:12 That's a that's a fury. But the
00:27:12 --> 00:27:14 wavelength the wavelength stretches. So
00:27:14 --> 00:27:17 the time the um the length scale is
00:27:18 --> 00:27:20 increasing. Um in fact there's there's a
00:27:20 --> 00:27:21 thing called the scale factor of the
00:27:21 --> 00:27:26 universe. Uh and it's very easy to
00:27:26 --> 00:27:28 prove. It's one of the most simple
00:27:28 --> 00:27:30 geometrical equations in cosmology. Uh
00:27:30 --> 00:27:34 the scale factor of the universe. uh now
00:27:34 --> 00:27:35 compared with when the light was emitted
00:27:36 --> 00:27:37 the ratio of the two is equal to 1 over
00:27:37 --> 00:27:40 1 plus zed uh where zed is the red shift
00:27:40 --> 00:27:42 of the light that you're measuring and
00:27:42 --> 00:27:44 so there's this direct link between the
00:27:44 --> 00:27:46 sort of scale size of the universe which
00:27:46 --> 00:27:49 is the length of a meter effectively um
00:27:49 --> 00:27:51 and the red shift that we measure when
00:27:51 --> 00:27:55 we look in deep into the universe um you
00:27:55 --> 00:27:57 look as though you got a question now
00:27:57 --> 00:27:59 I'm confused so what you're basically
00:27:59 --> 00:28:02 saying in regard to his question was
00:28:02 --> 00:28:06 that um the meter is expanding. So a
00:28:06 --> 00:28:08 meter is not a meter.
00:28:08 --> 00:28:11 >> Well, it's it's still a meter, but it's
00:28:11 --> 00:28:14 a different meter.
00:28:14 --> 00:28:18 Okay. Um because the scale factor of the
00:28:18 --> 00:28:22 universe was less when the light was
00:28:22 --> 00:28:23 emitted. This is the thing, you know,
00:28:23 --> 00:28:25 you've got two different reference
00:28:25 --> 00:28:28 frames here. That's why this stuff gets
00:28:28 --> 00:28:30 a little bit complicated because in our
00:28:30 --> 00:28:33 reference frame the meter is longer. But
00:28:33 --> 00:28:35 if you were traveling along with your
00:28:35 --> 00:28:39 meter stick uh as it as it sped through
00:28:39 --> 00:28:41 the universe uh it would be changing in
00:28:42 --> 00:28:44 length. It would it would sorry appear
00:28:44 --> 00:28:46 to be the same length.
00:28:46 --> 00:28:49 Right?
00:28:49 --> 00:28:51 I'm sorry. This is just
00:28:51 --> 00:28:55 it's mindbending,
00:28:55 --> 00:28:56 >> isn't it?
00:28:56 --> 00:29:00 >> It it bends mine as well. Um, and so
00:29:00 --> 00:29:02 something similar happens to time, but
00:29:02 --> 00:29:05 once again, so so we are we're we're
00:29:05 --> 00:29:08 still inside the universe, but we're
00:29:08 --> 00:29:12 we're observers from a in a different
00:29:12 --> 00:29:15 reference frame from when the light was
00:29:15 --> 00:29:16 emitted. Because that's what we're
00:29:16 --> 00:29:18 talking about. We're talking about being
00:29:18 --> 00:29:19 able to measure the expansion of the
00:29:19 --> 00:29:21 universe through the through the light
00:29:21 --> 00:29:23 waves.
00:29:23 --> 00:29:27 So, so and we know that time dilation
00:29:27 --> 00:29:29 took place. We can we can measure that
00:29:29 --> 00:29:32 by looking at this rise and fall rates
00:29:32 --> 00:29:34 of supernovi in the distant universe and
00:29:34 --> 00:29:36 they actually appear to rise and fall
00:29:36 --> 00:29:40 slower. So, it is the time uh element of
00:29:40 --> 00:29:41 that changes as well.
00:29:41 --> 00:29:44 >> Okay. I think he chose a meter because
00:29:44 --> 00:29:48 um the meter was defined by uh the
00:29:48 --> 00:29:51 international system of units as a as
00:29:51 --> 00:29:53 the length of the path light travels in
00:29:53 --> 00:29:56 a vacuum during a time inter interval of
00:29:56 --> 00:30:02 1 299
00:30:02 --> 00:30:05 of the second.
00:30:05 --> 00:30:07 >> Yeah, that's how it's that that's how
00:30:07 --> 00:30:09 it's defined today. It was originally
00:30:10 --> 00:30:11 defined as being what was it?
00:30:11 --> 00:30:13 1/400th of the circumference of the
00:30:13 --> 00:30:14 I can't remember.
00:30:14 --> 00:30:15 >> Yeah, I can't
00:30:15 --> 00:30:16 >> something like that.
00:30:16 --> 00:30:16 >> Yeah.
00:30:16 --> 00:30:18 >> All right.
00:30:18 --> 00:30:19 >> Okay. So,
00:30:19 --> 00:30:22 >> well, no, it would be 140. Uh, yeah.
00:30:22 --> 00:30:24 Anyway, it was like it was a it was
00:30:24 --> 00:30:26 related to the circumference of the
00:30:26 --> 00:30:27 earth.
00:30:27 --> 00:30:28 >> Can't do the sums anymore. My brain's
00:30:28 --> 00:30:30 fried today. I don't know why. I mean,
00:30:30 --> 00:30:32 you're right. I think it's episode 300
00:30:32 --> 00:30:34 600 is a a relativistic phenomenon
00:30:34 --> 00:30:35 taking place here.
00:30:35 --> 00:30:37 >> It it it's just messing us up. I mean,
00:30:37 --> 00:30:41 if we need a holiday of some kind. Um,
00:30:41 --> 00:30:43 but anyway, uh, hopefully that helped,
00:30:43 --> 00:30:46 Peter. I don't know. Uh,
00:30:46 --> 00:30:48 but, um, I think somewhere in there we
00:30:48 --> 00:30:50 did answer a question. Thanks for
00:30:50 --> 00:30:52 sending it in. And and and good to have
00:30:52 --> 00:30:56 a, um, a very Scandinavian sort of, uh,
00:30:56 --> 00:30:58 600th episode. So, um, yeah, I mean, we
00:30:58 --> 00:31:02 we've got Slatty Bfast, we've got Sweden
00:31:02 --> 00:31:04 a couple of times over, Norway, and then
00:31:04 --> 00:31:07 South Australia. Uh, okay. Well, no.
00:31:07 --> 00:31:09 Anyway, close enough. Close enough.
00:31:09 --> 00:31:11 >> South Australia is not known for its
00:31:11 --> 00:31:12 fjords, but it is a nice place.
00:31:12 --> 00:31:14 >> It is a lovely place, except it was
00:31:14 --> 00:31:16 pouring rain and gale force winds when
00:31:16 --> 00:31:17 we visited. But anyway, that's the way
00:31:18 --> 00:31:20 it goes. Uh, thank you, Peter Bjorn,
00:31:20 --> 00:31:22 Slatty Badfast, and Daryl for sending in
00:31:22 --> 00:31:23 questions. If you've got questions for
00:31:23 --> 00:31:26 us, please send them in to us via our
00:31:26 --> 00:31:28 website, spacenutspodcast.com,
00:31:28 --> 00:31:30 spacenuts.io.
00:31:30 --> 00:31:32 uh click on the AMA button which stands
00:31:32 --> 00:31:35 for ask me anything and send us your
00:31:35 --> 00:31:37 text or audio questions. Don't forget to
00:31:37 --> 00:31:38 tell us who you are and where you're
00:31:38 --> 00:31:40 from. We'd love to hear from you,
00:31:40 --> 00:31:42 especially if you haven't sent in
00:31:42 --> 00:31:45 questions before. Uh also, if you'd like
00:31:45 --> 00:31:47 to help us out, um please, wherever you
00:31:47 --> 00:31:50 listen to us, uh leave reviews because
00:31:50 --> 00:31:53 the more reviews the the better. uh the
00:31:53 --> 00:31:56 the more we move up the the
00:31:56 --> 00:31:59 relativistic food chain that is podcast
00:31:59 --> 00:32:02 world and uh we we get more listeners
00:32:02 --> 00:32:04 perhaps that's that's the aim of the
00:32:04 --> 00:32:06 game anyway uh if you could do that for
00:32:06 --> 00:32:08 us that would be great and Fred thank
00:32:08 --> 00:32:10 you very much nice to chat we'll catch
00:32:10 --> 00:32:12 you on the next episode
00:32:12 --> 00:32:14 >> sounds great Andrew uh hope we get our
00:32:14 --> 00:32:16 breath back before then
00:32:16 --> 00:32:18 >> yes yes it's been a bit tiring hasn't it
00:32:18 --> 00:32:20 but uh we got there in the end professor
00:32:20 --> 00:32:23 Fred Watson astronomer at and he'll be
00:32:23 --> 00:32:24 back with us next week. Uh Hugh in the
00:32:24 --> 00:32:26 studio. We thank him too for all the
00:32:26 --> 00:32:29 work he's done over these last um well
00:32:29 --> 00:32:31 actually he doesn't turn up for most. So
00:32:31 --> 00:32:33 the last four episodes that he's been
00:32:33 --> 00:32:35 with us. Um in fact he couldn't be with
00:32:35 --> 00:32:37 us today because we told him he could
00:32:37 --> 00:32:40 have every 600th episode off. And from
00:32:40 --> 00:32:42 me Andrew Dunley, thanks for your
00:32:42 --> 00:32:44 company. We'll see you on the next
00:32:44 --> 00:32:46 episode of Space Nuts. Bye-bye.
00:32:46 --> 00:32:47 >> Space Nuts.
00:32:47 --> 00:32:49 >> You've been listening to the Space Nuts
00:32:49 --> 00:32:51 podcast.
00:32:51 --> 00:32:54 Available at Apple Podcasts, Spotify,
00:32:54 --> 00:32:57 iHeart Radio, or your favorite podcast
00:32:57 --> 00:32:59 player. You can also stream on demand at
00:32:59 --> 00:33:02 byes.com. This has been another quality
00:33:02 --> 00:33:07 podcast production from byes.com.