Latest / Space News Today / Hawking Radiation, Dark Energy Dilemmas & Listener Curiosities | Space Nuts: Astronomy Insights...

Transcript

Hawking Radiation, Dark Energy Dilemmas & Listener Curiosities | Space Nuts: Astronomy Insights... · Space News Today

• 0:00
  Hello again. Thanks for joining us on
• 0:02
  Space Nuts. This is a Q&A edition. My
• 0:04
  name is Andrew Dunley and it's always
• 0:06
  good to have your company wherever you
• 0:08
  are in the world. Uh today we're going
• 0:12
  to be answering questions from our
• 0:14
  audience and we've got a question from
• 0:17
  Tony about Hawking radiation. Uh Stuart
• 0:20
  has asked a question about something
• 0:22
  we've never discussed before or have we
• 0:24
  discussed it a million times? It's
• 0:26
  called dark energy. And Thomas wants to
• 0:29
  know what would happen if we could just,
• 0:31
  you know, move Earth over there. Uh, all
• 0:35
  of those questions will be answered on
• 0:37
  today's episode of Space Nuts.
• 0:39
  >> 15 seconds. Guidance is internal. 10 9
• 0:44
  Ignition sequence start.
• 0:46
  >> Space Nuts.
• 0:46
  >> 5 4 3 2
• 0:49
  >> 1 2 3 4 5 5 4 3 2 1
• 0:51
  >> Space Nuts.
• 0:53
  >> Astronauts report. It feels good.
• 0:56
  >> He's back for more. His name is
• 0:58
  Professor Frag. What's an astronomer at
• 1:00
  large? Hello, Fred.
• 1:01
  >> Hello, Andrew. How are you after all
• 1:03
  that technical uh
• 1:06
  >> Yes. Um normally we record two episodes
• 1:09
  back to back with only moments in
• 1:11
  between, but today it was a very
• 1:13
  different story. Uh the internet would
• 1:15
  not cooperate.
• 1:17
  Um space doesn't cooperate either. I
• 1:19
  think they were in collusion. So, I
• 1:22
  mean, yeah, that left us high and dry,
• 1:25
  but it gave me time to make a cup of
• 1:26
  coffee.
• 1:27
  >> Very good.
• 1:28
  >> There it is. So,
• 1:29
  >> yeah,
• 1:31
  >> I've got one, too.
• 1:33
  >> Yes. Um, I love my coffee. I'm a I'm a
• 1:36
  nut for it. Uh, so let's um get stuck
• 1:40
  into some questions, shall we, Fred? Oh,
• 1:42
  before we do, though, uh we have a um a
• 1:46
  sort of an answer to one of our
• 1:47
  questions. We got an a question from
• 1:49
  Andy in London uh not so long ago and we
• 1:52
  we uh dealt with his um uh interests,
• 1:57
  but he he mentioned that he's a train
• 1:59
  driver and I just said, "Tell us more
• 2:02
  about your job." Really interested to
• 2:04
  learn. And he sent us a little bit of
• 2:06
  info about his job. And I like that we
• 2:09
  can do this. But I think uh you know
• 2:11
  we've created um or they've created
• 2:13
  themselves this interesting uh
• 2:16
  environment where a lot of the listeners
• 2:18
  can talk to each other on our podcast
• 2:21
  group on Facebook. Uh and it's nice to
• 2:25
  get to know a few people. So um this is
• 2:27
  this is Andy the train driver from
• 2:29
  London.
• 2:30
  >> Hi you guys. This is Andy the train
• 2:31
  driver from London. Uh thanks for
• 2:33
  answering my question. Uh much
• 2:35
  appreciated. Uh just we need to get back
• 2:37
  to you uh regarding um the question
• 2:40
  about trains. Yeah. So um I live in West
• 2:44
  Sussex but I actually work near Norwood
• 2:46
  Junction on the London Bridge Line. Um
• 2:50
  and I drive two of trains, one electric,
• 2:52
  one diesel. Uh both are about 50 tons
• 2:56
  per coach. So um longest train I drive
• 3:00
  is 12 coaches long. And so that equates
• 3:03
  to about 600 tons. Uh the diesel trains
• 3:06
  um I drive them from London Bridge down
• 3:08
  to West Sussex to a place called Arfield
• 3:11
  and they are uh they've got one engine
• 3:14
  per coach. Uh these engines are pretty
• 3:17
  similar to like a double-decker bus
• 3:19
  engine like 11 L turbocharged.
• 3:23
  So uh longest train to drive down there
• 3:25
  is 10 coaches. So you got 10 11 liter
• 3:28
  turbo engines all roaring away at the
• 3:31
  same time. Um sounds quite impressive.
• 3:34
  Yep. I've been doing it 22 years and I'm
• 3:38
  also an instructor. So, I teach all the
• 3:39
  new recruits how to drive these trains.
• 3:42
  Um I also do the um the DC lines and the
• 3:45
  AC lines which are the overhead cables
• 3:49
  uh 25,000 volts. Um and I drive the
• 3:52
  electric trains over to Watford
• 3:55
  um up to 100 miles an hour.
• 3:58
  So, yeah. Um it's good job. I enjoy it.
• 4:01
  Um I also enjoy your podcast. So, uh,
• 4:04
  thanks for for everything you do and I
• 4:07
  hope that answers your questions. Have a
• 4:09
  good day, guys. See you later. Bye.
• 4:11
  >> Thanks, Andy. Uh, I know that's got
• 4:13
  nothing to do with astronomy or space
• 4:15
  science, but I just thought it was um it
• 4:17
  was so good of him to tell us a little
• 4:19
  bit about his amazing life and his
• 4:21
  amazing job. And how many jobs do you
• 4:24
  know, Fred, where you're allowed to do
• 4:25
  over 100 miles an hour? I mean,
• 4:28
  >> well, you pay to do it as well. Yeah.
• 4:30
  >> Yeah. Yeah. What a great gig. Jeez,
• 4:32
  Andy, thanks a lot. That was fantastic.
• 4:34
  Really enjoyed hearing about you. My
• 4:36
  next door neighbor is a retired train
• 4:38
  driver. So, I'm going to um get him over
• 4:40
  here and and let him hear that because I
• 4:42
  think he'd be absolutely intrigued. And
• 4:44
  of course, there's been a lot of local
• 4:46
  interest lately because a whole set of
• 4:48
  new trains are being built in do for the
• 4:50
  regional lines. And uh I actually
• 4:53
  spotted one yesterday out doing a trial
• 4:55
  run and it's very quiet. I I thought I
• 4:59
  heard this sound and went, "What is
• 5:00
  that?" And I had a look and it whispered
• 5:03
  past. It was really um amazing. And Andy
• 5:06
  would be interested to know these these
• 5:08
  new trains that they're putting on
• 5:09
  regional New South Wales tracks are
• 5:11
  hybrids. So it'll run diesel from here
• 5:15
  to the city of Lithco and then they'll
• 5:18
  pop up the um the electric uh connector
• 5:20
  and run
• 5:22
  electric. Yeah. Yeah. And they'll run
• 5:25
  they'll run to Sydney.
• 5:26
  >> Yeah.
• 5:27
  >> On the electric
• 5:28
  >> line, which is uh Yeah. Awesome. So, um,
• 5:32
  yeah, lots of I love trains, so and and
• 5:35
  Judy's dad was a station master, so
• 5:37
  we've got a bit of a connection with
• 5:38
  with trains in our family and next door,
• 5:41
  as it turns out. Uh, we better get down
• 5:44
  to it though, Fred. We've got a bunch of
• 5:47
  questions to go through. And, uh, here's
• 5:49
  the first one. Hi, lads. Shane here from
• 5:51
  Ireland, and I have a question regarding
• 5:54
  Interstellar Comet 3 Atlas. I recently
• 5:57
  read an article that stated, "New
• 5:59
  studies indicate comet 3i Atlas could
• 6:01
  potentially be nearly as old as the
• 6:03
  universe itself." This got me to
• 6:05
  thinking about how a comet can exist for
• 6:07
  so long, potentially 13 billion years or
• 6:10
  so, and not burn up completely as it
• 6:13
  passes through solar systems. Even if it
• 6:16
  is as large as a few kilometers in
• 6:18
  diameter, it must burn off debris at an
• 6:20
  alarming rate for it to have a a coma
• 6:23
  thousands of kilometers in length uh
• 6:26
  that can be seen from Earth. My guess is
• 6:28
  that it has probably spent 99% of its
• 6:31
  time in freezing interstellar space. But
• 6:34
  even at 1% of the time spent passing
• 6:37
  through other solar systems should be
• 6:40
  enough to make it evaporate. Uh love the
• 6:42
  show. Keep up the good work. Over and
• 6:44
  out, Shane. Thank you, Shane. And um
• 6:47
  happy St. Patrick's Day, which was
• 6:49
  yesterday our time. And all the golfers
• 6:52
  at our course were dressed in green. So
• 6:55
  um yeah, that was fun. Sent me cuz I
• 6:57
  forgot. Um but uh yeah, what interesting
• 7:01
  question by Shane. Um is is that a thing
• 7:03
  that the threei Atlas could be that old?
• 7:07
  Um, yeah, the there's it's really
• 7:11
  interesting that there's new information
• 7:12
  coming out all the time about how
• 7:15
  different threeey atlases to the comets
• 7:18
  in our own solar system. In fact, I just
• 7:21
  saw one uh while we were off air um as
• 7:25
  as you were desperately trying to fix
• 7:27
  the um fix the interweb there. Uh I got
• 7:30
  saw a new story which is about the water
• 7:32
  content of three Atlas and it's um ratio
• 7:36
  of normal to heavy water which I haven't
• 7:38
  read yet but it's um again it's an
• 7:41
  outlier just like so many of its
• 7:43
  attributes are outliers. Uh I haven't
• 7:46
  seen reports that it might be as old as
• 7:47
  the universe. Um it it clearly won't be
• 7:51
  as old as you know it has to be
• 7:54
  middle-aged in the sense that uh some of
• 7:58
  the ices that we see in it are complex
• 8:01
  molecules. There's um the sort of u
• 8:07
  chemical mix that we see in the solar
• 8:10
  system except the the extremes in the
• 8:13
  way these you know the ratios of one to
• 8:15
  the other. Um, and for those elements
• 8:18
  all to be there, you must be talking
• 8:20
  about a solar system, its origin being
• 8:23
  in a solar system that is relatively
• 8:26
  rich in these elements. And that means
• 8:28
  it's not something in the very early
• 8:30
  universe where uh most you know there
• 8:33
  was just hydrogen, helium and iron were
• 8:36
  the most common constituents. It's got
• 8:39
  all the all the sort of array of
• 8:43
  chemistry or chemical elements that we
• 8:45
  are used to in the solar system. So, I
• 8:48
  think it's fair to say it's probably
• 8:50
  old, but um I'm not going to hazard a
• 8:52
  guess on how old it is. I've seen
• 8:54
  >> I just had a quick look, Fred, and uh as
• 8:56
  at March 2026, according to live
• 8:58
  science, it's possibly 10 to 12 billion
• 9:02
  years old. They think
• 9:04
  >> that's a lot, isn't it?
• 9:06
  >> That's old. Yeah. Um, but you've got to
• 9:08
  balance that against the fact that it
• 9:09
  does have um, you know, it does have a
• 9:11
  chemical composition in terms of the
• 9:14
  elements that are present, the
• 9:15
  abundances of the elements that's not
• 9:16
  too different from ours, but that's
• 9:19
  clearly something uh that the pundits
• 9:22
  are working on. Um the I think the the
• 9:27
  nub of uh of Shane's question is
• 9:33
  I think his estimate of 99 99% of its
• 9:37
  time being in deep space and 1% being
• 9:40
  passing through a solar system. I
• 9:42
  suspect that's
• 9:45
  probably wildly wrong. uh because I
• 9:47
  suspect that it's more like
• 9:48
  99.99999999999999%
• 9:52
  in deep space and a tiny fraction that
• 9:55
  would be passing through solar systems.
• 9:57
  And what makes me say that is that space
• 9:59
  is big.
• 10:00
  >> Um it's um it's there's a lot of empty
• 10:03
  space out there and the and the solar
• 10:05
  systems are yes they're everywhere we
• 10:08
  see them. You know, we can see stars and
• 10:10
  planets and all the rest of it, but the
• 10:12
  space between them is immense. Uh and so
• 10:16
  I yeah I think it's understandable uh
• 10:19
  that um an object as old as that let's
• 10:22
  say uh 10 10 to 12 billion years uh that
• 10:27
  could well have been um an object that
• 10:32
  has kept most of its primordial ice. Um,
• 10:36
  I don't think
• 10:38
  a lot is going to depend on how near it
• 10:41
  passes to a star when it's when it's
• 10:43
  going through a solar system. That's the
• 10:45
  crucial thing. How much radiation is it
• 10:47
  feeling from the star? How much of its
• 10:49
  ice sublimes into space? And uh it it
• 10:54
  it's a fairly small fraction I think of
• 10:56
  the total mass. I have seen work on
• 11:00
  trying to understand
• 11:02
  uh comets in our own solar system in
• 11:05
  terms of how many times they've passed
• 11:06
  near the sun and what that what the sort
• 11:09
  of mass loss uh has resulted from that.
• 11:12
  >> Yeah.
• 11:12
  >> Um but um they are falling in from the
• 11:15
  or cloud. So their orbits are quite
• 11:18
  different from three Atlas which is
• 11:20
  hurtling through the solar system at 60
• 11:23
  60 odd kilometers/s.
• 11:25
  Uh it's nowhere near the sun in that
• 11:27
  regard. So and and it doesn't have a big
• 11:30
  tail. It's got it does the images that
• 11:32
  we see show a short stubby tail um with
• 11:35
  the coma. So there is material coming
• 11:37
  off it. Um I wouldn't like to hazard a
• 11:39
  guess as to how much and I don't even
• 11:41
  know whether there's a reasonable
• 11:42
  estimate as to what the size of three
• 11:45
  eye atlas is in terms of the size of its
• 11:47
  nucleus, the icy bit.
• 11:49
  >> Yeah,
• 11:49
  >> you might be able to find that out as
• 11:50
  well. In terms of diameter, it's 440
• 11:54
  m.
• 11:56
  Um,
• 11:58
  hang on a sec. It's got all sorts of
• 12:00
  different numbers here. Based on 2025
• 12:02
  Hubble Space Telescope observations, the
• 12:05
  nucleus of the comet is between uh 440 m
• 12:09
  and 5.6 kilometers in diameter.
• 12:11
  >> Yeah. Yeah. It's pretty hard to
• 12:13
  >> big. Yeah,
• 12:15
  >> that's right. Because we don't see the
• 12:17
  nucleus itself. we just see the the coma
• 12:19
  around the nucleus as it out gases.
• 12:22
  >> Yeah.
• 12:22
  >> But, you know, maybe when it set off it
• 12:24
  was twice the size of that. Who knows?
• 12:26
  Um, but yeah, I think it's it's an
• 12:28
  interesting question that Shane um uh
• 12:31
  poses, but I think it's uh it's it
• 12:34
  probably all makes sense. I think the
• 12:35
  the numbers kind of add up even if it is
• 12:37
  very very old.
• 12:39
  >> Yeah, I'm sure. And how fast did you say
• 12:42
  60 kilometers a second?
• 12:43
  >> Something like that. Yes, it's in that
• 12:44
  range.
• 12:44
  >> That's nearly as fast as Andy the train
• 12:46
  driver.
• 12:50
  Well, that's right.
• 12:52
  Yeah. All right. Uh, so there it is,
• 12:55
  Shane. Thanks for the question.
• 12:57
  Hopefully, we uh adequately answered it
• 12:59
  for you. Our uh next question comes from
• 13:04
  somebody else. Hi, Professor Fred and
• 13:06
  Andrew. My question is concerning
• 13:08
  Hawking radiation. When two quantum
• 13:10
  particles pop into existence from a
• 13:12
  black hole, are the particles entangled?
• 13:15
  if not why. Uh also um you inform and
• 13:20
  educate us uh so well. So I thought I
• 13:23
  would share some remarkable stats I read
• 13:25
  the other day. The surface of the sun is
• 13:26
  very noisy. Forget the vacuum u thingy
• 13:30
  for a minute. The sun's surface
• 13:31
  apparently crackles away at 100 dibels,
• 13:33
  give or take. Uh the light from the sun
• 13:36
  takes approximately 8 minutes to reach
• 13:38
  us. However, the sound of the crackling
• 13:40
  sun would not reach us for 13 years. Uh,
• 13:44
  I love your show, Tony from Marrickville
• 13:46
  in New South Wales. PS. Looking forward
• 13:48
  to professor uh the professor's next
• 13:50
  Belrose presentation.
• 13:53
  What's that about, Fred?
• 13:55
  >> Uh, well, we've been doing these for
• 13:57
  quite a long time. Uh, it's something
• 13:59
  called Fred Watson Presents. Um, and uh
• 14:03
  uh we it's it's a sporadic thing we um
• 14:07
  put on a talk. Many of course the the
• 14:11
  mastermind behind all this arranges it.
• 14:13
  We've got a place in Belrose uh not very
• 14:15
  far from where we live here in Davidson
• 14:17
  in the Northern Beaches. Um and there's
• 14:19
  a nice bowling club there and we go and
• 14:21
  they've got a room which has a actually
• 14:23
  has a great screen. Uh and um I give
• 14:26
  talks from time to time. Once in a while
• 14:28
  we get a guest speaker as well who gives
• 14:29
  a talk. So we we maybe do three or four
• 14:32
  a year something like that.
• 14:34
  >> Lovely. Very nice. Well that's what he's
• 14:37
  talking about. Um those sun statistics
• 14:39
  are very interesting. You and you and I
• 14:41
  have talked about how loud the sun is
• 14:42
  before, so it's a good thing we can't
• 14:44
  hear it or we'd, you know, that's
• 14:46
  >> we'd be in trouble. Uh, but his question
• 14:49
  was about Hawking radiation. When two
• 14:51
  quantum particles pop into existence
• 14:53
  from a black hole, are the particles
• 14:55
  entangled? If not, why not? Um, yeah.
• 14:59
  So, that that's the that's the bottom
• 15:01
  line. And I know you're not a particle
• 15:04
  physicist.
• 15:06
  Uh but no but doing what you do uh check
• 15:08
  it out on on the interweb and the answer
• 15:11
  seems to be yes.
• 15:13
  So um formed together from vacuum energy
• 15:16
  these temporary particle antiparticle
• 15:18
  pairs share linked quantum properties
• 15:20
  like spin. And so um they are entangled.
• 15:25
  And that does sort of raise the
• 15:27
  question, doesn't it, that um when one
• 15:29
  of them sucked into the black hole and
• 15:31
  the other one's not uh and it radiates
• 15:33
  outwards, well, they become disentangled
• 15:35
  then because they would um they would be
• 15:38
  um
• 15:39
  >> they wouldn't be in what's called a
• 15:40
  state of superposition, which is the
• 15:42
  quantum state where, you know, things
• 15:45
  can be upside down and the right way up
• 15:46
  at the same time and things of that
• 15:48
  sort. So, uh, yeah, I think, um, they're
• 15:50
  they're probably entangled when they and
• 15:52
  and look, I'm kind of making this up,
• 15:54
  but, um, and some particle physicists
• 15:56
  might want to correct me, but I think
• 15:57
  they're entangled when they're formed,
• 15:59
  but I suspect cross one of them crossing
• 16:02
  the event horizon, uh, becomes
• 16:04
  disentangled very quickly.
• 16:06
  >> Yeah, I guess so. We've got about 10,000
• 16:08
  quantum um, physicists who listen to us,
• 16:11
  so one of them might give us an answer
• 16:14
  to that. Yes.
• 16:15
  >> Um and and how does this differ from
• 16:18
  string theory? Is that nothing to do
• 16:21
  with quantum entanglement?
• 16:22
  >> Um so string theory uh look is a is a um
• 16:30
  it's still conjectured. It's still not
• 16:33
  um a theory that has any um real
• 16:37
  evidence to support it. But that
• 16:40
  envisages pairs sorry particles as being
• 16:44
  like strings um as the name implies. So
• 16:47
  rather than a particle uh what you've
• 16:50
  got is something with an additional
• 16:52
  dimension and that uh the suggestion is
• 16:56
  that some of those dimensions are
• 16:58
  microscopic. They're wrapped up on the
• 17:00
  external surface of a string. Um I'm not
• 17:03
  sure what the interface between uh
• 17:06
  quantum sorry between string theory and
• 17:09
  quantum entanglement is and it's an
• 17:11
  interesting thought that you've thrown
• 17:13
  in there Andrew. I wouldn't mind reading
• 17:15
  up a little bit more about that because
• 17:16
  it's quite an interesting area. I used
• 17:18
  to do do talks about string theory most
• 17:21
  of which I've forgotten but they were
• 17:23
  the thing the thing about string theory
• 17:25
  is you do have to have additional
• 17:27
  dimensions other than the four that we
• 17:29
  know about. And a lot of theories
• 17:31
  postulate additional dimensions. Um if I
• 17:34
  remember rightly uh string theories
• 17:38
  had I know the numbers were ridiculous.
• 17:41
  I think some of them some of these
• 17:42
  theories needed 20 or more additional
• 17:44
  dimensions.
• 17:46
  Uh and so uh it it's um yeah it's uh uh
• 17:52
  hard to get your head around where all
• 17:54
  those dimensions might be lurking. Uh
• 17:56
  but they're hidden dimensions basically.
• 17:59
  Fascinating. Yeah. Gosh, I think I
• 18:01
  opened a can of worms.
• 18:03
  >> You did? Yeah. You didn't. All right. Um
• 18:07
  but yeah, the bottom line uh for um that
• 18:11
  question is yes. Yes. They they
• 18:15
  Yeah. The two quantum particles pop into
• 18:17
  existence at the same time, but we don't
• 18:20
  know what happens if one of them gets
• 18:21
  sucked in. Is that it?
• 18:23
  >> I think that's the bottom line. Yeah.
• 18:25
  >> Yeah. Wow. Fascinating. All right.
• 18:27
  Thanks, Tony. Thanks for the question.
• 18:29
  Hope all is well in Maricville. This is
• 18:31
  Space Nuts with Andrew Dunley and
• 18:34
  Professor Fred Watson.
• 18:37
  Let's take a break from the show to tell
• 18:39
  you about our sponsor, NordVPN.
• 18:42
  Now, if you've ever felt like your
• 18:44
  online privacy is slipping through the
• 18:46
  cracks, then you're not alone. hackers,
• 18:49
  scammers, harvesters, they're all out
• 18:50
  there trying to get your private info.
• 18:53
  Whether that's your passwords or your
• 18:54
  personal details to sell on the dark web
• 18:57
  or to use themselves to access your bank
• 19:00
  accounts, credit card details, and who
• 19:02
  knows what else. But you can protect
• 19:04
  yourself with NordVPN.
• 19:07
  You can take control at home or or more
• 19:10
  importantly when you're out in public
• 19:12
  using free Wi-Fi. right now. Uh, using
• 19:16
  the exclusive Space Nuts offer, you can
• 19:19
  receive four extra months for free on a
• 19:23
  NordVPN.com
• 19:25
  plan. NordVPN encrypts your internet
• 19:29
  connection, hides your IP address, and
• 19:31
  offers access to over 7,700 servers
• 19:34
  around the world. Plus, with features
• 19:37
  like threat protection pro, meshet,
• 19:41
  ultra fast speeds via Nord links, your
• 19:44
  digital life stays private and
• 19:47
  efficient. So, don't miss out. Visit
• 19:50
  nordvpn.com/spacenuts
• 19:53
  and enter the code spacenuts to claim
• 19:56
  this deal. Remember, there's a 30-day
• 19:58
  money back guarantee, so it's riskfree
• 20:01
  to try. Stay safe, stay private, and
• 20:04
  browse with confidence. That's
• 20:06
  nordvpn.com/spacenuts.
• 20:12
  >> G, and I feel
• 20:13
  >> space nuts.
• 20:15
  >> Okay, Fred, we'll go straight to our
• 20:16
  next question. Uh, this one comes from
• 20:19
  Stuart. Good day. This is Stuart from
• 20:22
  Tasmania, home of the very cute little
• 20:24
  Tasmanian devil. I just had a question
• 20:26
  about dark energy and how it's
• 20:28
  propelling the expansion of the
• 20:30
  universe. Uh we know it's dark in the
• 20:33
  sense that it's mysterious, but I was
• 20:35
  also wondering about the use of the word
• 20:37
  energy. Uh considering the current
• 20:39
  theory says that having propelled the
• 20:41
  universe to expand, the level of dark
• 20:44
  energy does not decrease in our area and
• 20:48
  the new area of space has just as much
• 20:50
  dark energy in it. I was just wondering
• 20:53
  how this would be possible given the
• 20:55
  current understanding of the laws of
• 20:56
  physics and the conservation of energy.
• 20:59
  I was just wondering if you could give
• 21:01
  us an update on the current thinking
• 21:03
  with regard to all this and uh maybe I'm
• 21:05
  missing out on some new breakthroughs.
• 21:06
  Thank you.
• 21:08
  >> Thank you, Stuart. Uh love Tasmania,
• 21:10
  beautiful place and uh I I I would bork
• 21:14
  at calling a um Tasmanian devil cute.
• 21:18
  I have seen them devour a rabbit and uh
• 21:22
  they don't leave a thing. They eat
• 21:25
  absolutely everything. The bones, the
• 21:27
  fur, and everything in between. They
• 21:30
  they um they are the perfect nature's
• 21:33
  perfect garbage mulchure. Absolutely.
• 21:38
  So, um yeah,
• 21:40
  thanks for the info, Stuart. Um Fred,
• 21:44
  yes, it's a great question and there
• 21:47
  there is um new thinking on dark energy.
• 21:50
  Uh it it is counterintuitive that um as
• 21:54
  you make more space you make more energy
• 21:57
  uh because you've got to come from
• 21:59
  somewhere. Um but uh all right so what's
• 22:03
  the observation that leads to this idea?
• 22:05
  It's the fact that uh all the evidence
• 22:07
  points to an accelerated expansion of
• 22:09
  the universe. Uh and that has been known
• 22:13
  since 19 1998.
• 22:16
  uh we have attributed that acceleration
• 22:20
  to this phenomenon of dark energy which
• 22:23
  is I always think of it as a kind of
• 22:25
  springiness of space um and the bigger
• 22:29
  space gets the springier it becomes
• 22:30
  springier it becomes and that's the sort
• 22:34
  of standard model of dark energy which
• 22:37
  uh is puts a term into some of
• 22:40
  Einstein's theories of relativity uh
• 22:44
  which is he called the cosmological
• 22:46
  constant and it was a term that he
• 22:49
  invented in the mathematics to allow for
• 22:52
  the fact
• 22:54
  in fact he put it there because before
• 22:56
  when when he was doing this work he
• 22:58
  didn't know that the universe was
• 23:00
  expanding at all and so here he had to
• 23:02
  put this cosmological constant in to
• 23:05
  stop the universe expanding or
• 23:06
  contracting he thought it was static and
• 23:09
  then when in 1929 Hubble discovered that
• 23:12
  the universe is expanding he sort of
• 23:14
  regretted that And he in a conversation
• 23:16
  I think with George Gamoff around uh I
• 23:20
  don't know in the 40s or 50s he said it
• 23:22
  was the biggest blunder of his life the
• 23:23
  cosmological constant but uh when people
• 23:28
  realize that the expansion of the
• 23:30
  universe is actually accelerating
• 23:33
  then the cosmological constant suddenly
• 23:35
  became one way of explaining that or at
• 23:38
  least modeling it modeling what was
• 23:39
  happening. If it's the co cosmological
• 23:42
  constant that's doing this, then what
• 23:45
  you've got is an increase in energy that
• 23:48
  is proportional to the increase in
• 23:51
  space. So as the volume increases, you
• 23:53
  get a proportional amount of energy
• 23:55
  increase. That's because the energy per
• 23:57
  unit volume is constant. That's where
• 24:00
  the idea of a constant logical constant
• 24:02
  comes from. So um that uh that has been
• 24:06
  the model until recently because we
• 24:08
  didn't have any uh observations to
• 24:12
  support anything else. But as you and I
• 24:15
  have spoken about Andrew the um latest
• 24:18
  thinking and it comes from the dark
• 24:20
  energy survey uh a major survey of the
• 24:24
  positions and velocities of galaxies
• 24:26
  that actually give you some idea of
• 24:28
  what's going on on the big picture side
• 24:30
  of the universe. uh looking back several
• 24:33
  billion years in in our um you know time
• 24:37
  timewise direction as we look out into
• 24:39
  space always looking back in time. Uh so
• 24:41
  the latest thinking seems to suggest
• 24:44
  that the the cosmological constant isn't
• 24:47
  constant uh because it looks as though
• 24:50
  the acceleration is actually slowing
• 24:53
  down or reducing. uh and that's led to
• 24:57
  uh conversations that you and I have had
• 24:59
  that maybe one day the acceleration
• 25:01
  would turn into a deceleration and then
• 25:03
  we might well return to the era of the
• 25:06
  big crunch or the gnab gib. Um I I'll
• 25:10
  I'll put an aside in here Andrew just
• 25:12
  for your benefit. Um one of our I can't
• 25:15
  remember who it was. One of our
• 25:17
  listeners said the Gab Gibb sounds like
• 25:20
  one of the Lost Beij brothers.
• 25:23
  >> Yes. Um, and I I I told you uh in the
• 25:26
  last episode that I was narrating some
• 25:29
  music in a couple of concerts down in
• 25:31
  Canra over the weekend
• 25:33
  >> and I threw that one in
• 25:35
  >> and it went down an absolute treat. So,
• 25:39
  um, so thank you. Um, was it was it was
• 25:43
  it Martin? Yes, I had a feeling it was
• 25:45
  Martin. Uh, so Martin, thank you for
• 25:48
  that. He gave me a really He gave you
• 25:50
  gave Fred a joke and um he doesn't tell
• 25:54
  many jokes. So um
• 25:55
  >> well actually most of my talks are one
• 25:58
  constant joke I have to say. You've
• 26:00
  never heard one. You probably have
• 26:02
  actually a long time ago but yeah I do
• 26:04
  try try and throw in as much lightness
• 26:05
  as I can and that hit the spot
• 26:08
  perfectly. So thank you Martin. I really
• 26:10
  enjoyed that. Right back to the story.
• 26:13
  Uh so there won't be a gab gibb a big
• 26:15
  crunch uh unless the acceleration really
• 26:18
  turns into a deceleration and that would
• 26:21
  modify how we understand just coming
• 26:24
  back to Stuart's question how we
• 26:26
  understand that you know the energy uh
• 26:29
  constant of the universe and um I think
• 26:33
  it leads you to the sort of thing we
• 26:36
  were just talking about higher
• 26:38
  dimensions and new physics physics we
• 26:40
  don't understand uh I think if the uh
• 26:44
  the decelerating sorry the decreasing
• 26:46
  acceleration of the universe is going to
• 26:48
  be properly explained. We may well have
• 26:51
  to invoke new physics that currently are
• 26:54
  unknown. So uh this is cutting edge
• 26:57
  stuff. It's very exciting. Uh and we'll
• 27:00
  just see where it goes and you'll
• 27:01
  probably hear about it on Space Studio.
• 27:04
  Yes, it it's such a um a big area to try
• 27:08
  and understand and there's there's um we
• 27:11
  I think we're really only at the dawn of
• 27:13
  the um the process of of unraveling what
• 27:17
  dark energy is all about and we've said
• 27:19
  before it's it's poorly named. It's
• 27:22
  probably yeah it's creating so much
• 27:24
  confusion with dark matter which is also
• 27:26
  probably poorly named. But anyway,
• 27:29
  >> um Stuart might be interested to go to
• 27:31
  the darkenerys survey.org or website uh
• 27:35
  if he wants to find out more because
• 27:36
  there's plenty of information there and
• 27:38
  they're updating what they're learning
• 27:40
  or studying all the time. So, um yeah,
• 27:43
  darken energy survey.org
• 27:46
  uh could be a good port of call for you,
• 27:49
  Stuart. Uh and have fun down there with
• 27:52
  your Tasmanian devils. Uh when Judy and
• 27:54
  I went to Tasmania on our honeymoon,
• 27:57
  believe it or not, she never let me
• 27:58
  forget it. Um, one of the most common
• 28:01
  roadkills we saw were Tasmanian
• 28:04
  devilles, which is very sad, but um,
• 28:06
  yeah, that there were quite a few of
• 28:08
  them lying on the sides of the roads,
• 28:09
  which is, I guess, um, you know, it's
• 28:13
  unique to Tasmania. Uh, here it's
• 28:15
  kangaroos and more kangaroos.
• 28:18
  Okay, thanks Stuart. Uh, we'll go on to
• 28:20
  our final question. Hello, Space Nuts.
• 28:22
  This is Thomas from Virginia. So, and
• 28:26
  this is a what if question, Fred. I love
• 28:27
  what if questions. So, if you had a way
• 28:30
  to push Earth to another stars
• 28:33
  Goldilocks zone when our sun starts to
• 28:36
  die, what would happen to the atmosphere
• 28:39
  on the way? I assume it would freeze,
• 28:41
  but then what would happen to it after
• 28:44
  that? So, um yeah, that comes from
• 28:46
  Thomas. Uh it reminds me of a movie I
• 28:49
  watched. Um and I must confess I didn't
• 28:52
  finish it. It just got too much for me.
• 28:54
  I I love science fiction, but this one
• 28:56
  just threw me over the edge. It was a I
• 28:59
  can't remember the title of it, but um
• 29:02
  Earth had to move because there was an
• 29:04
  issue probably with the sun and they
• 29:06
  wanted to move us out to Jupiter and so
• 29:09
  they attached all these giant rockets to
• 29:11
  Earth and it just got crazier from
• 29:14
  there. Uh but let's say you could what
• 29:16
  would happen to our atmosphere?
• 29:20
  >> Um it it's a great question. Uh because
• 29:25
  there are, you know, when you think of
• 29:28
  gas giants, they've got atmospheres that
• 29:30
  are uh still gaseous, well outside the
• 29:34
  the Goldilock zone. Um possibly partly
• 29:38
  because the those bodies are radiating
• 29:40
  heat themselves as is the Earth at a
• 29:43
  very low level. Uh the Earth has some
• 29:46
  low-level nuclear reactions going on in
• 29:48
  its nucleus in the center uh at the core
• 29:51
  of the Earth. And so um there is a
• 29:53
  little bit of heat comes from the earth
• 29:55
  itself uh that might stop it freezing.
• 29:58
  Um so
• 30:01
  I I I'm sort of draw the parallel that I
• 30:04
  would draw in my head is with with the
• 30:08
  dwarf planet Pluto which does have an
• 30:10
  atmosphere. Uh it's very very thin. uh
• 30:15
  uh but a lot of the kind of atmospheric
• 30:19
  constituents of the earth are actually
• 30:22
  frozen at the distance of Pluto. Um so I
• 30:26
  think what is it minus 230 or
• 30:29
  thereabouts the the temperature at Pluto
• 30:32
  on the surface uh the nitrogen uh is is
• 30:36
  frozen because you've got nitrogen
• 30:39
  glaciers there and um sort of slushy
• 30:42
  slushy nitrogen flowing around. Um so I
• 30:46
  suspect that might happen to the earth's
• 30:48
  atmosphere but there would be a residual
• 30:51
  level of air I think. Uh but when you
• 30:54
  got back to your Goldilock zone in
• 30:56
  another solar system, hopefully it would
• 30:58
  all just come good again and you know
• 31:01
  your nitrogen starts to be a gas rather
• 31:03
  than a rather than a a solid. Uh and um
• 31:08
  you could with with there might be some
• 31:11
  loss of of components of the atmosphere,
• 31:13
  but generally I think what you might
• 31:15
  have is something much the same as you
• 31:17
  set off with. That's my guess anyway. I
• 31:21
  don't think we have to take Earth that
• 31:22
  far though if you know when the sun
• 31:25
  expands and we just have to move out a
• 31:28
  little bit we
• 31:29
  >> that I think that's right you know
• 31:32
  >> um but the problem is as you said um
• 31:35
  it's just science fiction to think of
• 31:37
  moving a planet uh we don't have any way
• 31:40
  of doing that at the moment other than
• 31:42
  the only other way to do it will be to
• 31:44
  hit it with another planet but that
• 31:46
  brings its own concerns that would
• 31:51
  as we spoke about in the last episode.
• 31:53
  Although Yeah, indeed. That's right.
• 31:55
  Indeed.
• 31:55
  >> Wouldn't wouldn't be a good effect. Um
• 31:58
  maybe we could employ string theory and
• 32:00
  just drag ourselves out there.
• 32:03
  >> Who knows? Well, if there's extra hidden
• 32:05
  dimensions, we might be able to pop the
• 32:07
  Earth into one of them and come out
• 32:08
  somewhere else. I think if you did find
• 32:11
  a way to move Earth to a better place
• 32:13
  when required, you'd have to put people
• 32:15
  somewhere else in the meantime. She'd
• 32:18
  probably survive the journey on the
• 32:20
  planet itself.
• 32:23
  A bit tough. Um, but yeah, interesting
• 32:26
  question, Thomas. But yes, this South
• 32:28
  Koreans did make a movie about this very
• 32:30
  concept if you want to look it up. I
• 32:32
  can't remember the name. Um, I don't
• 32:35
  want to. I didn't I didn't really enjoy
• 32:38
  it. It was a weird weird film, but they
• 32:40
  do make weird movies in in South Korea,
• 32:42
  so it's right up there. They love their
• 32:45
  science fiction, though. Um, thanks,
• 32:47
  Thomas. Great to hear from you. And if
• 32:49
  you have questions for us, please,
• 32:51
  please, please go to our website and
• 32:53
  click on the ask me anything tab at the
• 32:55
  top where you can send us text and audio
• 32:58
  questions. Uh, we still struggling to
• 33:00
  get audio questions. People don't want
• 33:02
  to talk to us, Fred. I think that's what
• 33:03
  it comes down to. spaceodcast.com
• 33:07
  and spacets.io
• 33:09
  are the two URLs that will work. And
• 33:11
  while you're there, have a look around.
• 33:13
  Um, and and please leave reviews on your
• 33:17
  favorite podcasting platform. The more
• 33:19
  reviews the better, apparently, unless
• 33:21
  they're, you know, one star. Um, don't
• 33:25
  really like those, but, you know, you
• 33:26
  get the occasional one, I suppose. Uh,
• 33:29
  there it is, Fred. Thanks so much. Great
• 33:31
  to catch up.
• 33:32
  >> It is. Uh, thank you for having me and
• 33:35
  um, sorry about all the glitches earlier
• 33:36
  on.
• 33:37
  >> It's all good. It's all good. Professor
• 33:39
  Fred Watson, astronomer at large. We'll
• 33:41
  catch him on the next episode and thanks
• 33:43
  to Hugh in the studio who couldn't be
• 33:45
  with us today because they called him
• 33:47
  out to fix the internet. So, he'll be
• 33:49
  back in about 300 years. And from me,
• 33:52
  Andrew Dunley, thanks for your company.
• 33:54
  We'll see you on the next episode of
• 33:55
  Space Nuts. Bye-bye.
• 33:57
  >> Space Nuts. You've been listening to the
• 33:59
  Space Nuts podcast
• 34:02
  >> available at Apple Podcasts, Spotify,
• 34:05
  iHeart Radio, or your favorite podcast
• 34:08
  player. You can also stream on demand at
• 34:10
  byes.com. This has been another quality
• 34:13
  podcast production from byes.com.