Latest / Space Nuts: Astronomy Insights & Cosmic Discoveries / Hawking Radiation, Dark Energy Dilemmas & Listener Curiosities

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Hawking Radiation, Dark Energy Dilemmas & Listener Curiosities · Space Nuts: Astronomy Insights & Cosmic Discoveries

• 0:00
  Speaker 1: Hello again, thanks for joining us on Space Nuts. This
• 0:02
  Speaker 1: is a Q and A edition. My name is Andrew Dunkley,
• 0:05
  Speaker 1: and it's always good to have your company wherever you
• 0:08
  Speaker 1: are in the world. Today we're going to be answering
• 0:13
  Speaker 1: questions from our audience, and we've got a question from
• 0:17
  Speaker 1: Tony about Hawking radiation. Stewart has asked a question about
• 0:22
  Speaker 1: something we've never discussed before, or have we discussed it
• 0:25
  Speaker 1: a million times. It's called dark energy, and Thomas wants
• 0:29
  Speaker 1: to know what would happen if we could just, you know,
• 0:32
  Speaker 1: move Earth over there. All of those questions will be
• 0:36
  Speaker 1: answered on today's episode of Space Nuts fifteen seconds. Guidance
• 0:40
  Speaker 1: is in Channel ten nine ignition sequence Space Nuts NY
• 0:47
  Speaker 1: or three.
• 0:48
  Speaker 2: Two more Redio one Space Nuts as the night report.
• 0:53
  Speaker 1: It Bill's good, He's back for more. His name is
• 0:58
  Speaker 1: Professor Accred. What's on a at Large? Hello Fred?
• 1:01
  Speaker 3: Hello Andrew? How are you after all that technical?
• 1:07
  Speaker 1: Normally we record two episodes back to back with only
• 1:10
  Speaker 1: moments in between, but today it was a very different story.
• 1:14
  Speaker 1: The Internet would not cooperate. Space doesn't cooperate either. I
• 1:19
  Speaker 1: think they were in collusion. So yeah, that left us
• 1:24
  Speaker 1: high and drive. But it gave me time to make
• 1:26
  Speaker 1: a cup of copy. Very good there it is, So.
• 1:31
  Speaker 3: I've got one too.
• 1:32
  Speaker 1: Yes, I love coffee. I'm a nut for it. So
• 1:39
  Speaker 1: let's get stuck into some questions, shall we fret? Oh,
• 1:42
  Speaker 1: before we do, though, we have a sort of an
• 1:46
  Speaker 1: answer to one of our questions. We got a question
• 1:49
  Speaker 1: from Andy in London not so long ago, and we
• 1:53
  Speaker 1: dealt with his interests. But he mentioned that he's a
• 1:59
  Speaker 1: train driver and I just said, tell us more about
• 2:02
  Speaker 1: your job, really interested to learn, and he said us
• 2:06
  Speaker 1: a little bit of info about his job. And I
• 2:08
  Speaker 1: like that we can do this. I think you know,
• 2:11
  Speaker 1: we've created, or they've created themselves, this interesting environment where
• 2:17
  Speaker 1: a lot of the listeners can talk to each other
• 2:19
  Speaker 1: on our podcast group on Facebook, and it's nice to
• 2:25
  Speaker 1: get to know a few people. So this is Andy
• 2:28
  Speaker 1: the train driver from London.
• 2:30
  Speaker 4: Hi, guys, this is Andy the train driver from London.
• 2:33
  Speaker 4: Thanks for answering my question. Much appreciate. Just we need
• 2:37
  Speaker 4: to go back to regarding the question about trains. Yeah,
• 2:42
  Speaker 4: so I live in West Sussex, but I actually work
• 2:46
  Speaker 4: near Nord Junction on the London Bridge Line and I
• 2:50
  Speaker 4: drive too tart the trains one electric, one diesel. Both
• 2:55
  Speaker 4: are about fifty tons per coach, so longest trainer driver
• 3:00
  Speaker 4: is twelve coaches long, and so that craates to about six
• 3:03
  Speaker 4: hundred tons. The diesel trains, I've drive them from London
• 3:07
  Speaker 4: Bridge down to West Sussex to a place called Uckfield,
• 3:11
  Speaker 4: and they are they've got one engine per coach. These
• 3:16
  Speaker 4: engines are pretty similar to like a double decker bus
• 3:19
  Speaker 4: engine like eleven liter turbo charged. So the longest train
• 3:24
  Speaker 4: to drive down there is ten coaches. So you've got
• 3:27
  Speaker 4: ten eleven liter turbo engines all roaring away at the
• 3:31
  Speaker 4: same time. Sounds quite impressive. Yep.
• 3:35
  Speaker 1: I've been doing it.
• 3:35
  Speaker 4: Twenty two years and I'm also an instructor, so a
• 3:39
  Speaker 4: teacher with the new recruits how to drive these trains.
• 3:43
  Speaker 4: I also do the DC lines and the AC lines,
• 3:46
  Speaker 4: which are the overhead cables twenty five thousand vaults, and
• 3:52
  Speaker 4: I'll drive the electric trains over to Watford up to
• 3:55
  Speaker 4: one hundred miles an hour.
• 3:58
  Speaker 1: So yeah, it's a good job. I enjoy it.
• 4:02
  Speaker 4: I also enjoy your podcast, So thanks well for everything
• 4:05
  Speaker 4: you do and I hope I answered your questions.
• 4:09
  Speaker 1: Have good day, guys, So you like to buy. Thanks Andy.
• 4:12
  Speaker 1: I know that's got nothing to do with astronomy or
• 4:15
  Speaker 1: space science, but I just thought it was so good
• 4:18
  Speaker 1: of him to tell us a little bit about his
• 4:19
  Speaker 1: amazing life and his amazing job. And how many jobs
• 4:23
  Speaker 1: do you know, Fred were you're allowed to do over
• 4:25
  Speaker 1: one hundred miles an hour? I mean, well you paid
• 4:29
  Speaker 1: to do it as well. Yeah, what a great gig. Jeez, Andy,
• 4:33
  Speaker 1: thanks a lot. That was fantastic. I really enjoyed hearing
• 4:35
  Speaker 1: about you. My next door neighbors are retired train driver,
• 4:38
  Speaker 1: so I'm going to get him over here and let
• 4:41
  Speaker 1: him hear that, because I think he'd be absolutely intrigued,
• 4:44
  Speaker 1: and because there's been a lot of local interest lately,
• 4:47
  Speaker 1: because the whole set of new trains are being built
• 4:49
  Speaker 1: in Dubbo for the regional lines, and I actually spotted
• 4:54
  Speaker 1: one yesterday out doing a trial run and it's very quiet.
• 4:58
  Speaker 1: I thought, I heard this sound, went what is that?
• 5:01
  Speaker 1: And I had a look and it whispered past. It
• 5:04
  Speaker 1: was really amazing, and Andy would be interested to know.
• 5:07
  Speaker 1: These these new trains that they're putting on regional New
• 5:10
  Speaker 1: South Wales tracks are hybrids, so it'll run diesel from
• 5:14
  Speaker 1: here to the city. Of liftgo and then they'll pop
• 5:18
  Speaker 1: up the electric connector and run on school electric group. Yeah, yeah,
• 5:24
  Speaker 1: and they'll run They'll run to Sydney on the electricty Wine,
• 5:29
  Speaker 1: which is awesome. So yeah, lots of I love trains,
• 5:35
  Speaker 1: and Judy's dad was a station master, so we've got
• 5:37
  Speaker 1: a bit of a connection with trains in our family
• 5:41
  Speaker 1: and next door. As it turns out, we better get
• 5:44
  Speaker 1: down to it though, Fred, We've got a bunch of
• 5:46
  Speaker 1: questions to go through. And here's the first one. Hi.
• 5:50
  Speaker 1: Lad's Shane here from Oil and and I have a
• 5:53
  Speaker 1: question regarding interstellar comets three atlas. I recently read an
• 5:57
  Speaker 1: article that stated new studies indicate common at three I
• 6:00
  Speaker 1: atlas could potentially be nearly as old as the universe itself.
• 6:05
  Speaker 1: This got me to thinking about how comet can exist
• 6:07
  Speaker 1: for so long, potentially thirteen billion years or so, and
• 6:11
  Speaker 1: not burn up completely as it passes through solar systems.
• 6:14
  Speaker 1: Even if it is as large as a few kilometers
• 6:17
  Speaker 1: in diameter, it must burn off debris at an alarming
• 6:21
  Speaker 1: rate for it to have a coma thousands of kilometers
• 6:24
  Speaker 1: in length that can be seen from Earth. My guess
• 6:28
  Speaker 1: is that it has probably spent ninety nine percent of
• 6:31
  Speaker 1: its time in freezing into stellar space, but even at
• 6:34
  Speaker 1: one percent of the time spent passing through other solar
• 6:38
  Speaker 1: systems should be enough to make it evaporate. Love the show,
• 6:42
  Speaker 1: keep up the good work over and out, Shane. Thank
• 6:45
  Speaker 1: you Shane, and happy Saint Patrick's Day, which was yesterday
• 6:50
  Speaker 1: our time, and all the golfers at our course were
• 6:53
  Speaker 1: dressed in green. So yeah, that was fun except me
• 6:57
  Speaker 1: because I forgot. But yeah, the interesting question by Shane
• 7:02
  Speaker 1: is that a thing that the Three Eye Atlas could
• 7:05
  Speaker 1: be that old.
• 7:08
  Speaker 3: Yeah, it's really interesting that there's new information coming out
• 7:13
  Speaker 3: all the time about how different three Eye atlases to
• 7:17
  Speaker 3: the comets in our own solar system. In fact, I
• 7:20
  Speaker 3: just saw one while we were off air, as you
• 7:26
  Speaker 3: were desperately trying to fix the fix the interweb there.
• 7:30
  Speaker 3: I got a new story which is about the water
• 7:32
  Speaker 3: content of Three Eye Atlas and is a ratio of
• 7:36
  Speaker 3: normal to heavy water, which I haven't read yet, but
• 7:39
  Speaker 3: it's again it's an outlier, just like so many of
• 7:43
  Speaker 3: its attributes are outliers. I haven't seen reports that it
• 7:46
  Speaker 3: might be as old as the universe. It clearly won't
• 7:50
  Speaker 3: be as old as you know, it has to be
• 7:54
  Speaker 3: middle aged in the sense that some of the ice
• 7:59
  Speaker 3: is that we see in it are complex molecules. There's
• 8:05
  Speaker 3: the sort of chemical mix that we see in the
• 8:10
  Speaker 3: solar system, except their extremes in the way these you know,
• 8:14
  Speaker 3: the ratios of one to the other, and for those
• 8:17
  Speaker 3: elements all to be there, you must be talking about
• 8:21
  Speaker 3: a solar system its origin being in a solar system
• 8:24
  Speaker 3: that is relatively rich in these elements, and that means
• 8:28
  Speaker 3: it's not something in the very early universe where most
• 8:33
  Speaker 3: you know, there was just hydrogen, helium and iron were
• 8:36
  Speaker 3: the most common constituents. It's got all the sort of
• 8:42
  Speaker 3: array of chemistry or chemical elements that we are used
• 8:46
  Speaker 3: to in the solar system. So I think it's fair
• 8:49
  Speaker 3: to say it's probably old, but I'm not going to
• 8:51
  Speaker 3: hazard a guess on how old it is.
• 8:53
  Speaker 1: I've seen had a quick look for it in as
• 8:56
  Speaker 1: at March twenty twenty six. According to Live Science, it's
• 9:00
  Speaker 1: possibly ten to twelve billion years old. They think that's
• 9:05
  Speaker 1: a lot that's old.
• 9:06
  Speaker 3: Yeah, but you've got to balance that against the fact
• 9:09
  Speaker 3: that it does have you know, it does have a
• 9:11
  Speaker 3: chemical composition in terms of the elements that are present,
• 9:14
  Speaker 3: the abundances of the elements. That's not too different from ours.
• 9:18
  Speaker 3: But that's clearly something that the pundits are working on.
• 9:25
  Speaker 1: I think the nub of.
• 9:29
  Speaker 3: Change question is I think his estimate of ninety nine
• 9:34
  Speaker 3: point ninety nine percent of its time being in deep
• 9:38
  Speaker 3: space and one percent being passing through a solar system.
• 9:42
  Speaker 3: I suspect that's probably wildly wrong, because I suspect that
• 9:48
  Speaker 3: it's more like ninety nine point nine nine nine nine
• 9:50
  Speaker 3: nine nine nine nine nine percent in deep space and
• 9:54
  Speaker 3: a tiny fraction that would be passing through solar systems.
• 9:57
  Speaker 3: And what makes me say that is that space is big.
• 10:02
  Speaker 3: There's a lot of empty space out there, and the
• 10:05
  Speaker 3: solar systems are Yes, they're everywhere we see them, you know,
• 10:09
  Speaker 3: we can see stars and planets and all the rest
• 10:11
  Speaker 3: of it, but the space between them is immense. And
• 10:15
  Speaker 3: so yeah, I think it's understandable that an object as
• 10:21
  Speaker 3: old as that, let's say ten to twelve billion years,
• 10:26
  Speaker 3: that could well have been an object that has kept
• 10:33
  Speaker 3: most of its primordial ice. I don't think a lot
• 10:39
  Speaker 3: is going to depend on how near it passes to
• 10:41
  Speaker 3: a star. When it's when it's going through a solar system.
• 10:44
  Speaker 3: That's the crucial thing. How much radiation is it feeling
• 10:47
  Speaker 3: from the star? How much of its ice sublimes into space,
• 10:52
  Speaker 3: And it's a fairly small fraction I think of the
• 10:56
  Speaker 3: total mass. I have seen work on trying to understand
• 11:03
  Speaker 3: comets in our own solar system in terms of how
• 11:05
  Speaker 3: many times if passed near the Sun, and that what
• 11:08
  Speaker 3: the sort of mass loss has resulted from that. But
• 11:14
  Speaker 3: they are falling in from the oat cloud, so their
• 11:17
  Speaker 3: orbits are quite different from Three Eye Atlas, which is
• 11:20
  Speaker 3: hurtling through the Solar system at sixty sixty odd kilometers
• 11:24
  Speaker 3: per second. It's nowhere near the Sun in that regard,
• 11:27
  Speaker 3: so and it doesn't have a big tail.
• 11:30
  Speaker 1: It does.
• 11:31
  Speaker 3: The images that we see show a short, stubby tail
• 11:35
  Speaker 3: with the coma, So there is material coming off it.
• 11:38
  Speaker 3: I wouldn't like to hazard I guess as to how much.
• 11:40
  Speaker 3: And I don't even know whether there's a reasonable estimate
• 11:43
  Speaker 3: as to what the size of three Eye atlases in
• 11:46
  Speaker 3: terms of the size of its nucleus the icy bit, Yeah,
• 11:49
  Speaker 3: you might be able to find that out as well.
• 11:51
  Speaker 1: In terms of diameter, it's four hundred and forty meters
• 11:58
  Speaker 1: hang on a say, it's got all sorts of different numbers. Here,
• 12:01
  Speaker 1: based on twenty twenty five Hubble Space Telescope of observations,
• 12:04
  Speaker 1: the nucleus of the comet is between four hundred and
• 12:08
  Speaker 1: forty meters and five point six kilo meters in diameter.
• 12:12
  Speaker 3: Yeah, it's pretty hard to be. Yeah, that's right, because
• 12:16
  Speaker 3: we don't see the nucleus itself. We just see the
• 12:19
  Speaker 3: coma around the nucleus as the dark gases. But you know,
• 12:23
  Speaker 3: maybe when it set off it was tril the size
• 12:25
  Speaker 3: of that, who knows, But yeah, I think it's it's
• 12:27
  Speaker 3: an interesting question that Shane poses, but I think it's
• 12:34
  Speaker 3: it probably all makes sense. I think that the numbers
• 12:36
  Speaker 3: kind of add up, even if it is very very old.
• 12:39
  Speaker 1: Yeah, I'm sure. And how fast did you say? Sixty
• 12:42
  Speaker 1: kilometers a.
• 12:42
  Speaker 3: Second something like that? Yes, it's in that.
• 12:44
  Speaker 1: That's nearly as fast as Andy the train driver.
• 12:50
  Speaker 3: Well that's right.
• 12:52
  Speaker 1: Yeah, all right, So there it is, Shane. Thanks for
• 12:56
  Speaker 1: the question. Hopefully we adequately answered it for you. Our
• 13:01
  Speaker 1: next question comes from somebody else, Hi, Professor Fred and Andrew.
• 13:06
  Speaker 1: My question is concerning Hawking radiation, when two quantum particles
• 13:11
  Speaker 1: pop into existence from a black hole. Are the particles entangled?
• 13:15
  Speaker 1: If not, why also you inform an educators so well?
• 13:22
  Speaker 1: So I thought I would share some remarkable stats I
• 13:24
  Speaker 1: read the other day. The surface of the sun is
• 13:26
  Speaker 1: very noisy. Forget the vacuum thingy for a minute. The
• 13:30
  Speaker 1: Sun's surface apparently crackles away at one hundred decer bells
• 13:33
  Speaker 1: give or take. The light from the sun takes approximately
• 13:37
  Speaker 1: eight minutes to reach us. However, the sound of the
• 13:40
  Speaker 1: crackling sun would not reach us for thirteen years. I
• 13:44
  Speaker 1: love your show, Tony from Marrickville in New South Wales
• 13:47
  Speaker 1: PS looking forward to Professor the Professor's next Belrose presentation.
• 13:53
  Speaker 1: What's that about, Fred?
• 13:55
  Speaker 3: Well, we've been doing this for quite a long time,
• 13:58
  Speaker 3: something called Fred Watson pre sense and is a sporadic thing.
• 14:06
  Speaker 3: We put on a talk money of course, the mastermind
• 14:11
  Speaker 3: behind all this arranges it. We've got a place in Belrose,
• 14:15
  Speaker 3: not very far from where we live here in Davidson
• 14:17
  Speaker 3: in the Northern Beaches, and there's a nice bowling club
• 14:20
  Speaker 3: there and we can't They've got a room which actually
• 14:23
  Speaker 3: has a great screen, and I give talks from time
• 14:26
  Speaker 3: to time. Once in a while we get a guest
• 14:28
  Speaker 3: speaker as well, who gives au talk. So we maybe
• 14:31
  Speaker 3: do three or four a year something like that.
• 14:34
  Speaker 1: Lovely, very nice. Well that's what he's talking about. Those
• 14:38
  Speaker 1: sun statistics are very interesting, and you and I have
• 14:41
  Speaker 1: talked about how loud the sun is before, so it's
• 14:43
  Speaker 1: a good thing we can't hear at all, you know,
• 14:46
  Speaker 1: we've been in trouble. But his question was about Hawking radiation.
• 14:51
  Speaker 1: When two quantum particles pop into existence from a black hole,
• 14:54
  Speaker 1: are the particles entangled? If not? Why not? Yeah, so
• 15:00
  Speaker 1: that's the that's the bottom line. And now you're not
• 15:03
  Speaker 1: a particle physicist.
• 15:06
  Speaker 3: But no, but doing what you do, check it out
• 15:08
  Speaker 3: on the interweb and the answer seems to be yes. So,
• 15:14
  Speaker 3: formed together from vacuum energy, these temporary particle anti particle
• 15:18
  Speaker 3: pairs share linked to quantum properties like spin, and so
• 15:23
  Speaker 3: they are entangled. And that does to raise the question,
• 15:27
  Speaker 3: doesn't it that when one of them sucked into the
• 15:30
  Speaker 3: black hole and the other one's not and it radiates outwards,
• 15:33
  Speaker 3: well they become disentangled then, because they would be they
• 15:39
  Speaker 3: wouldn't be in what's called a state of superposition, which
• 15:42
  Speaker 3: is the quantum state where you know, things can be
• 15:45
  Speaker 3: upside down in the right way up at the same time,
• 15:47
  Speaker 3: and things of that sort. So yeah, I think they're
• 15:50
  Speaker 3: probably entangled when they and look, I'm kind of making
• 15:53
  Speaker 3: this up, but some particle physicists might want to correct me.
• 15:57
  Speaker 3: But I think they're entangled when they're formed. I suspect
• 16:00
  Speaker 3: across one of them crossing the event horizon becomes disentangled
• 16:04
  Speaker 3: very quickly.
• 16:06
  Speaker 1: Yeah, I guess. So we've got about ten thousand quantum
• 16:09
  Speaker 1: physicists who listen to us, so one of them might
• 16:13
  Speaker 1: give us an answer to that. And how does this
• 16:17
  Speaker 1: differ from string theory? Is that nothing to do with
• 16:21
  Speaker 1: quantum entanglement.
• 16:24
  Speaker 3: So string theory, look, it's still conjectured, it's still not
• 16:33
  Speaker 3: a theory that has any real evidence to support it.
• 16:39
  Speaker 3: But that envisages pairs sorry particles as being like strings,
• 16:46
  Speaker 3: as the name implies. So rather than a particle, what
• 16:49
  Speaker 3: you've got is something with an additional dimension, and that
• 16:55
  Speaker 3: the suggestion is that some of those dimensions are microscopic.
• 16:59
  Speaker 3: They're wrapped up on the external surface of a string.
• 17:03
  Speaker 3: I'm not sure what the interface between quantum sorry between
• 17:08
  Speaker 3: string theory and quantum entanglement is, and it's an interesting
• 17:12
  Speaker 3: thought that you've.
• 17:12
  Speaker 1: Thrown in there, Andrew.
• 17:14
  Speaker 3: I won't mind reading up a little bit more about that,
• 17:16
  Speaker 3: because it's quite an interesting area. It used to do
• 17:19
  Speaker 3: talks about string theory, most of which I've forgotten. But
• 17:23
  Speaker 3: the thing about string theory is you do have to
• 17:26
  Speaker 3: have additional dimensions other than the four that we know about,
• 17:30
  Speaker 3: and a lot of theories postulate additional dimensions. If I
• 17:34
  Speaker 3: remember right, list string theories had now, the numbers were ridiculous.
• 17:41
  Speaker 3: I think some of them. Some of these theories needed
• 17:43
  Speaker 3: twenty or more additional dimensions, and so it's yeah, it's
• 17:52
  Speaker 3: hard to get your head around where all those dimensions
• 17:55
  Speaker 3: might be lurking, but they're hidden dimensions, basically fascinating.
• 18:00
  Speaker 1: Yeah, gosh, I think I opened a can of worms.
• 18:03
  Speaker 1: You did, all right, But yeah, the bottom line for
• 18:10
  Speaker 1: that question is yes, yes, they Yeah, the two quantum
• 18:16
  Speaker 1: particles pop into existence at the same time, but we
• 18:19
  Speaker 1: don't know what happens if one of them gets sucked in?
• 18:22
  Speaker 1: Is it?
• 18:23
  Speaker 3: I think that's the bottom line.
• 18:24
  Speaker 1: You Yeah, Wow, fascinating, All right, Thanks Tony, Thanks for
• 18:28
  Speaker 1: the question. Hopefull as well. In Marrickville. This is Space
• 18:32
  Speaker 1: Nuts with Andrew Dunkley and Professor Fred Watson. Let's take
• 18:38
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  Speaker 1: your pace nuts. Okay, Fred, We'll go straight to our
• 20:16
  Speaker 1: next question. This one comes from.
• 20:19
  Speaker 3: Stuart's Good This is Stuart from Tasmania, home of the
• 20:23
  Speaker 3: very cute little Tasmanian Devil.
• 20:26
  Speaker 2: I just had a question about dark energy and how
• 20:28
  Speaker 2: it's propelling the expansion of the universe. We know it's
• 20:32
  Speaker 2: dark in the sense that it's mysterious, but I was
• 20:35
  Speaker 2: also wondering about the use of the word energy considering
• 20:38
  Speaker 2: the current theory says that having propelled the universe to expand,
• 20:43
  Speaker 2: the level of dark energy does not decrease in our area,
• 20:47
  Speaker 2: and the new area of space has just as much
• 20:50
  Speaker 2: dark energy in it. I was just wondering how this
• 20:53
  Speaker 2: would be possible given the current understanding of the laws
• 20:56
  Speaker 2: of physics and the conservation of energy. Wondering if you
• 21:00
  Speaker 2: could give us an update on the current thinking with
• 21:03
  Speaker 2: regard to all this, and maybe I'm missing out on
• 21:05
  Speaker 2: some new breakthroughs.
• 21:06
  Speaker 1: Thank you, Thank you. Stuart loved Tasmania a beautiful place
• 21:11
  Speaker 1: and I would balk at calling a Tasmanian devil cute.
• 21:18
  Speaker 1: I have seen them devour a rabbit and they don't
• 21:23
  Speaker 1: leave a thing. They eat absolutely everything, the bones, the fur,
• 21:28
  Speaker 1: and everything in between. They are the perfect Nature's perfect
• 21:33
  Speaker 1: garbage multa. Absolutely so, yeah, thanks for the info, Stuart Fred.
• 21:44
  Speaker 3: Yes, it's a great question, and there is new thinking
• 21:49
  Speaker 3: on dark energy. It is counterintuitive that as you make
• 21:55
  Speaker 3: more space, you make more energy, because you've got to
• 21:58
  Speaker 3: come from somewhere. But all right, so what's the observation
• 22:03
  Speaker 3: that leads to this idea. It's the fact that all
• 22:06
  Speaker 3: the evidence points to an accelerated expansion of the universe,
• 22:11
  Speaker 3: and that has been known since nineteen ninety eight. We
• 22:17
  Speaker 3: have attributed that acceleration to this phenomenon of dark energy,
• 22:23
  Speaker 3: which is I always think of it as a kind
• 22:25
  Speaker 3: of springiness of space, and the bigger space gets the springery,
• 22:30
  Speaker 3: it becomes springier it becomes and that's the sort of
• 22:34
  Speaker 3: standard model of dark energy, which is put a term
• 22:39
  Speaker 3: into some of Einstein's theories of relativity, which he called
• 22:45
  Speaker 3: the cosmological constant, and it was a term that he
• 22:49
  Speaker 3: invented in the mathematics to allow for the fact. In fact,
• 22:54
  Speaker 3: he put it there because before when he was doing
• 22:58
  Speaker 3: this work, he didn't know that the verse was expanding
• 23:01
  Speaker 3: at all, and so he had to put this cosmological
• 23:03
  Speaker 3: constant in to stop the universe expanding or contracting. He
• 23:07
  Speaker 3: thought it was static, and then when in nineteen twenty
• 23:11
  Speaker 3: nine Hubble discovered that the universe is expanding, he sort
• 23:14
  Speaker 3: of regretted that, and he in a conversation I think
• 23:16
  Speaker 3: with George Gamoff around I don't know, in the forties
• 23:20
  Speaker 3: or fifties, he said it was the biggest blunder of
• 23:22
  Speaker 3: his life, the cosmological constant. But when people realize that
• 23:29
  Speaker 3: the expansion of the universe is actually accelerating, then the
• 23:33
  Speaker 3: cosmological constant suddenly became one way of explaining that, or
• 23:38
  Speaker 3: at least modeling it, modeling what was happening. If it's
• 23:41
  Speaker 3: a cosmological constant that's doing this, then what you've got
• 23:46
  Speaker 3: is an increase in energy that is proportional to the
• 23:49
  Speaker 3: increase in space. So as the volume increases, you get
• 23:54
  Speaker 3: a proportional amount of energy increase. That's because the energy
• 23:57
  Speaker 3: per unit volume is constant. That's where the idea of
• 24:00
  Speaker 3: asological constant comes from.
• 24:03
  Speaker 1: So that.
• 24:06
  Speaker 3: Has been the model until recently. Because we didn't have
• 24:10
  Speaker 3: any observations to support anything else. But as you and
• 24:14
  Speaker 3: I have spoken about, Andrew, the latest thinking, and it
• 24:19
  Speaker 3: comes from the Dark Energy Survey, a major survey of
• 24:24
  Speaker 3: the positions and velocities of galaxies that actually give you
• 24:27
  Speaker 3: some idea of what's going on on the big picture
• 24:30
  Speaker 3: side of the universe, looking back several billion years in
• 24:35
  Speaker 3: our time wise direction as we look out into space,
• 24:39
  Speaker 3: always looking back in time. So the latest thinking seems
• 24:43
  Speaker 3: to suggest that the cosmological constant isn't constant because it
• 24:49
  Speaker 3: looks as though the acceleration is actually slowing down or reducing.
• 24:55
  Speaker 3: And that's led to conversations that you and I have
• 24:59
  Speaker 3: had that maybe one day the acceleration would turn into
• 25:01
  Speaker 3: a deceleration and then we might well return to the
• 25:05
  Speaker 3: era of the Big Crunch or the ganab gibb. I'll
• 25:10
  Speaker 3: put an aside in here, Andrew, just for your benefit.
• 25:14
  Speaker 3: One of our I can't remember who it was, one
• 25:17
  Speaker 3: of our listeners said, the gannab GiB sounds like one
• 25:20
  Speaker 3: of the lost Beg Brothers. Yes, and I told you
• 25:26
  Speaker 3: in the last episode that I was narrating some music
• 25:30
  Speaker 3: in a couple of concerts down in Canberra over the
• 25:32
  Speaker 3: weekend and I threw that one in and it went
• 25:35
  Speaker 3: down an absolute treat, So, so thank you. Was it Martin? Yes,
• 25:44
  Speaker 3: I had a feeling it was Martin, So Martin, thank
• 25:48
  Speaker 3: you for that.
• 25:49
  Speaker 1: You think of me? Were really gave you gave Fred
• 25:51
  Speaker 1: a joke. He doesn't tell many jokes so well.
• 25:56
  Speaker 3: Actually most of my talks are at one constant joke.
• 25:58
  Speaker 3: I have to say, you've never heard one. You probably
• 26:02
  Speaker 3: have actually a long time ago. But yeah, I do
• 26:04
  Speaker 3: try and throw in as much lightness as I can
• 26:06
  Speaker 3: and that hit the spot perfectly. So thank you Martin.
• 26:10
  Speaker 3: I really enjoyed that. Right back to the story, So
• 26:14
  Speaker 3: there won't be a gonna GiB a big crunch unless
• 26:17
  Speaker 3: the acceleration really turns into a deceleration, and that would
• 26:21
  Speaker 3: modify how we understand Just coming back to Stewart's question,
• 26:25
  Speaker 3: how we understand that? You know the energy constant of
• 26:30
  Speaker 3: the universe, and I think it leads you to the
• 26:36
  Speaker 3: sort of thing we were just talking about higher dimensions
• 26:39
  Speaker 3: and new physics, physics we don't understand. I think if
• 26:42
  Speaker 3: the decelerating, sorry the decreasing acceleration of the universe is
• 26:48
  Speaker 3: going to be properly explained, we may well have to
• 26:51
  Speaker 3: invoke new physics that currently are unknown. So this is
• 26:56
  Speaker 3: cutting edge stuff. It's very exciting and we'll just see
• 27:00
  Speaker 3: where it goes and you'll probably hear about it on
• 27:02
  Speaker 3: Space Nuts, Stuart.
• 27:04
  Speaker 1: Yes, it's such a big area to try and understand,
• 27:09
  Speaker 1: and there's I think we're really only at the dawn
• 27:13
  Speaker 1: of the process of unraveling what dark energy is all about.
• 27:18
  Speaker 1: And we've said before it's poorly named. It's probably it's
• 27:23
  Speaker 1: creating so much confusion with dark matter, which is also
• 27:26
  Speaker 1: probably poorly named. But anyway, Stewart might be interested to
• 27:30
  Speaker 1: go to the Dark Energy Survey dot org website if
• 27:35
  Speaker 1: he wants to find out more, because there's plenty of
• 27:37
  Speaker 1: information there and they're updating what they're learning or studying
• 27:41
  Speaker 1: all the time. So yeah, dark energy survey dot org
• 27:46
  Speaker 1: could be a good port of call for you. Stuart,
• 27:50
  Speaker 1: and I have fun down there with your Tasmanian Devils
• 27:53
  Speaker 1: when Judy and I went to Tasmania on our honeymoon,
• 27:57
  Speaker 1: believe it or not, she never let me forget it,
• 28:00
  Speaker 1: and one of the most common roadkills we saw at
• 28:03
  Speaker 1: Tasmanian Devils, which is very sad, but yeah, there were
• 28:07
  Speaker 1: quite a few of them lying on the sides of
• 28:09
  Speaker 1: the roads, which is I guess you know it's unique
• 28:13
  Speaker 1: to Tasmania. Here it's kangaroos and more kangaroos. Okay, thanks Stuet.
• 28:19
  Speaker 1: We'll go on to our final question. Hello, space nuts.
• 28:22
  Speaker 1: This is Thomas from Virginia. So this is a what
• 28:26
  Speaker 1: if question? Fred, I love what if questions. So if
• 28:29
  Speaker 1: you had a way to push Earth to another star's
• 28:33
  Speaker 1: Goldilocks zone when our Sun starts to die, what would
• 28:37
  Speaker 1: happen to the atmosphere on the way. I assume it
• 28:40
  Speaker 1: would freeze, but then what would happen to it after that?
• 28:45
  Speaker 1: So yeah, that comes from Thomas. It reminds me of
• 28:48
  Speaker 1: a movie I watched, and I must confess I didn't
• 28:52
  Speaker 1: finish it. It just got too much for me. I
• 28:55
  Speaker 1: love science fiction, but this one just threw me over
• 28:58
  Speaker 1: the edge. It was I can't remember the title of it,
• 29:01
  Speaker 1: but Earth had to move because there was an issue,
• 29:04
  Speaker 1: probably with the Sun, and they wanted to move out
• 29:07
  Speaker 1: to Jupiter and so they attached all these giant rockets
• 29:10
  Speaker 1: to Earth and it just got grazier from there. But
• 29:15
  Speaker 1: let's say he could what would happen to our atmosphere.
• 29:21
  Speaker 3: It's a great question because there are you know, when
• 29:26
  Speaker 3: you think of gas giants, they've got atmospheres that are
• 29:31
  Speaker 3: still gaseous well outside the Goldilock zone, possibly partly because
• 29:39
  Speaker 3: those bodies are radiating heat themselves, as is the Earth
• 29:42
  Speaker 3: at a very low level. The Earth has some low
• 29:46
  Speaker 3: level nuclear reactions going on in its nucleus in the center,
• 29:51
  Speaker 3: the core of the Earth, and so there is a
• 29:53
  Speaker 3: little bit of heat comes from the Earth itself that
• 29:56
  Speaker 3: might stop it freezing. So I'm sort of drawing. The
• 30:03
  Speaker 3: parallel that I would draw in my head is with
• 30:07
  Speaker 3: the dwarf planet Pluto, which does have an atmosphere. It's
• 30:13
  Speaker 3: very very thin, but a lot of the kind of
• 30:18
  Speaker 3: atmosphere constituents of the Earth are actually frozen at the
• 30:24
  Speaker 3: distance of Pluto. So I think, what is it minus
• 30:28
  Speaker 3: two hundred and thirty or thereabouts the temperature that Pluto
• 30:32
  Speaker 3: on the surface, and the nitrogen is frozen because you've
• 30:37
  Speaker 3: got nitrogen glaciers there sort of slushy slushy nitrogen flowing around.
• 30:45
  Speaker 3: So I suspect that might happen to the Earth's atmosphere,
• 30:49
  Speaker 3: but there would be a residual level of air, I think,
• 30:53
  Speaker 3: but when you got back to your Goldilocks zone in
• 30:56
  Speaker 3: another solar system, hopefully it would all just come good again.
• 31:00
  Speaker 3: And you know, your nitrogen starts to be a gas
• 31:03
  Speaker 3: rather than a rather than a solid, and you could
• 31:09
  Speaker 3: with there might be some loss of components of the atmosphere,
• 31:13
  Speaker 3: but generally I think what you might have is something
• 31:16
  Speaker 3: much the same as you set off with. That's my guess.
• 31:19
  Speaker 1: Anyway. I don't think we have to take a sep
• 31:22
  Speaker 1: farther if you know, when the Sun expands and we
• 31:27
  Speaker 1: just have to move out a little bit.
• 31:29
  Speaker 3: But I think that's right, you know. But the problem is,
• 31:33
  Speaker 3: as you said, it's just science fiction to think of
• 31:37
  Speaker 3: moving a planet. We don't have any way of doing
• 31:40
  Speaker 3: that at the moment, other than the only other way
• 31:43
  Speaker 3: to do it will be to hit it with another planet,
• 31:45
  Speaker 3: But that brings its own concerns.
• 31:47
  Speaker 1: That would work, as we spoke about in the last episode.
• 31:53
  Speaker 3: Although yeah, indeed that's right, it did.
• 31:55
  Speaker 1: Wouldn't be a good effect. Maybe we could employee string
• 31:59
  Speaker 1: theory and drag ourselves out there.
• 32:03
  Speaker 3: Who knows, well, if this extra hidden dimensions, we might
• 32:06
  Speaker 3: be able to pop the Earth into one of them
• 32:08
  Speaker 3: and come out somewhere else.
• 32:09
  Speaker 1: I think if you did find a way to move
• 32:11
  Speaker 1: Earth to a better place when required, you'd have to
• 32:14
  Speaker 1: put people somewhere else. In the meantime, you'd probably survived
• 32:19
  Speaker 1: the journey on the planet gep It tough, but yeah,
• 32:25
  Speaker 1: interesting question, Thomas. But yes this South Koreans did make
• 32:29
  Speaker 1: a movie about this very concept if you want to
• 32:32
  Speaker 1: look it up. I can't remember the name. I don't
• 32:34
  Speaker 1: want to. I didn't really enjoy it. It was a weird,
• 32:39
  Speaker 1: weird film. But they do make weird movies in South Korea,
• 32:42
  Speaker 1: so it's right up there. They love their science fiction though.
• 32:47
  Speaker 1: Thanks Thomas. Great to hear from you, And if you
• 32:49
  Speaker 1: have questions for us, please please please go to our
• 32:52
  Speaker 1: website and click on the Ask Me Anything tab at
• 32:55
  Speaker 1: the top where you can send us text and audio questions.
• 32:59
  Speaker 1: We still struggling to get audio questions. People don't want
• 33:02
  Speaker 1: to talk to us, fred I think that's what it
• 33:03
  Speaker 1: comes down to. Podcast dot com at space That's dot
• 33:08
  Speaker 1: io are the two r ls that will work. Man.
• 33:11
  Speaker 1: While you're there, have a look around, and please leave
• 33:15
  Speaker 1: reviews on your favorite podcasting platform. The more reviews, the better.
• 33:20
  Speaker 1: Apparently unless they're you know, one star is. Don't really
• 33:25
  Speaker 1: like those, but you know you get the occasional one.
• 33:27
  Speaker 1: I suppose there it is. Fred, thanks so much, great
• 33:31
  Speaker 1: to catch up it is.
• 33:33
  Speaker 3: Thank you for hubbing me, and sorry about all the
• 33:36
  Speaker 3: glitches earlier on.
• 33:37
  Speaker 1: It's All Good. It's all good. Professor Fred Watson, Astronomer
• 33:40
  Speaker 1: at Large. We'll catch him on the next episode. And
• 33:43
  Speaker 1: thanks to Hugh in the studio who couldn't be with
• 33:46
  Speaker 1: us today because they called him out to fix the internet,
• 33:49
  Speaker 1: so he'll be back in about three hundred years. And
• 33:51
  Speaker 1: from me Andrew Dunkley, thanks for your company. We'll see
• 33:54
  Speaker 1: you on the next episode of Space Nuts. Bye bye
• 33:59
  Speaker 1: to the Space Nuts podcast. Available at Apple Podcasts, Spotify, iHeartRadio,
• 34:06
  Speaker 1: or your favorite podcast player. You can also stream on
• 34:09
  Speaker 1: demand at bites dot com. This has been another quality
• 34:13
  Speaker 1: podcast production from nights dot Com.