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Cosmic Connections: Mapping Magnetic Fields, Dark Matter Mysteries & SpaceX's IPO Success · Space Nuts: Astronomy Insights & Cosmic Discoveries

• 0:00
  Andrew Dunkley: Hello again. Thanks for joining us on another
• 0:02
  episode of Space Nuts. My name is Andrew
• 0:04
  Dunkley. It's great to have your company. I
• 0:06
  hope you're well. Uh, coming up in this
• 0:08
  episode, some exciting storeys. And
• 0:11
  one of them is a new
• 0:13
  CSIRO map
• 0:16
  developed in Australia of
• 0:19
  magnetic fields. Now, it's been quite a while
• 0:21
  since they updated this and they've got a new
• 0:23
  one out. And, uh, it's quite extraordinary,
• 0:26
  uh, the way it was done and what it shows and
• 0:28
  what it can be used for. Uh, we've also got
• 0:31
  a new report about the relationship
• 0:34
  or otherwise between, uh, black holes
• 0:36
  and dark matter. Now this is interesting
• 0:39
  because it's only been a theory
• 0:41
  until now. Now, this isn't absolute
• 0:44
  proof, but it's a step closer to
• 0:47
  proving there is something going on between
• 0:49
  the two of them and they just don't want
• 0:51
  anyone to know. And the world's first
• 0:53
  trillionaire goes public. We'll talk
• 0:56
  about all of that on this episode of space
• 0:59
  nuts.
• 1:00
  Professor Fred Watson: 15 seconds. Guidance is internal.
• 1:02
  10, 9. Ignition
• 1:05
  sequence start.
• 1:06
  Professor Fred Watson: Space nuts.
• 1:07
  Professor Fred Watson: 5, 4, 3, 2. 1, 2, 3, 4,
• 1:10
  5, 5, 4, 3, 2, 1.
• 1:12
  Andrew Dunkley: Space nuts.
• 1:13
  Professor Fred Watson: Astronauts report it feels good.
• 1:16
  Andrew Dunkley: And he's with us again for another dose of
• 1:19
  whatever it is he takes before he talks to
• 1:21
  me.
• 1:21
  It's Professor Fred Watson Watson, Astronomer
• 1:23
  at, uh, large. Hello, Fred Watson.
• 1:25
  Professor Fred Watson: It's good cup of tea that I take
• 1:27
  normally.
• 1:29
  Andrew Dunkley: Uh, I've been drinking a bit more
• 1:32
  tea of late. Um, only because, um,
• 1:36
  by the afternoon I'm not really into coffee.
• 1:38
  But today I did have coffee, so.
• 1:41
  Do love my coffee.
• 1:43
  Professor Fred Watson: I do too, but I make my own.
• 1:45
  Andrew Dunkley: I got the whole barista thing going.
• 1:48
  I'm even doing latte art, Fred Watson.
• 1:50
  Professor Fred Watson: Oh, really?
• 1:51
  Andrew Dunkley: Yeah. I don't know if you'll see this. I took
• 1:53
  this photo, um,
• 1:56
  today of my latte art. Can you see that?
• 1:59
  Professor Fred Watson: That is brilliant.
• 2:00
  Professor Fred Watson: Yeah.
• 2:01
  Andrew Dunkley: Whoa.
• 2:01
  Professor Fred Watson: That's real pro stuff. Self taught
• 2:03
  barista.
• 2:05
  Professor Fred Watson: Yes.
• 2:06
  Andrew Dunkley: I don't know what it is. It's like some kind
• 2:08
  of flower, like a lotus flower.
• 2:09
  Professor Fred Watson: Well, it reminds me of ears of corn.
• 2:12
  Andrew Dunkley: Oh, yeah, it does, doesn't it? Yeah, yeah,
• 2:14
  yeah, that's what it was. Or just ducks
• 2:16
  sitting on top of each other or something.
• 2:17
  Professor Fred Watson: Could be your. Could be your corny latte.
• 2:20
  Andrew Dunkley: Yes, it could be. Anyway, I've been working
• 2:23
  on that.
• 2:23
  Professor Fred Watson: That's very good. Yeah.
• 2:25
  Andrew Dunkley: I was going to do a whole series and put them
• 2:27
  on Instagram of my progression through being
• 2:30
  really crap at it and to reaching a
• 2:32
  point where it's, you know, something to look
• 2:35
  at, but I didn't bother and now I wish I had
• 2:37
  because I've had some epic fails.
• 2:40
  But um, that one came out quite well today.
• 2:43
  Professor Fred Watson: That's very nice. Well done.
• 2:44
  Andrew Dunkley: M. Right, let's uh, let's get on with this
• 2:47
  because, uh, we've got a lot to talk about as
• 2:49
  always.
• 2:50
  And our first storey comes from Australia,
• 2:53
  mate. And it is the uh,
• 2:56
  remapping of uh, the magnetic
• 2:58
  fields of a, uh, large swathe of
• 3:01
  um, uh, the universe. Or is it a large
• 3:04
  swathe of uh, whatever piece of the backyard
• 3:07
  sky someone can see out of. Not sure how much
• 3:09
  of it they
• 3:10
  Professor Fred Watson: got a good chunk of it
• 3:13
  actually. I, uh, thought so because, um.
• 3:16
  So these observations were made
• 3:19
  at uh, uh, a site in
• 3:22
  Western Australia known as Inyariman il Ghare
• 3:24
  Bundara, which is Wajari for
• 3:27
  sharing sky and stars. The Wodgery people are
• 3:29
  the traditional owners there. And it's also
• 3:32
  called the CSIRO Murchison Radio Astronomy
• 3:34
  Observatory, but we tend to refer to it as
• 3:36
  Inyarimana il Ghari Bundara because it's a
• 3:39
  very nice name. Uh,
• 3:42
  so what's there? There is, um, first of
• 3:45
  all, um, it's the site for the
• 3:47
  Low Frequency, uh, arm, um, of the
• 3:50
  Square Kilometre Array. Uh, Square Kilometre
• 3:53
  Array Observatory exists in three places.
• 3:56
  Uh, one is western, earlier where the Low
• 3:58
  Frequency antennas are. The uh, other is
• 4:00
  in South Africa where the mid Frequency
• 4:03
  antennas are. And the other is near
• 4:05
  Manchester where the headquarters are. Um,
• 4:08
  that's Chodrell bank is where the
• 4:10
  headquarters of SKAO are. Uh, uh, and
• 4:13
  they've just got a new Director General, uh,
• 4:15
  by the way, um, Jessica Dempsey I think is
• 4:18
  her name. Somebody I've kind of run
• 4:21
  into before over the years. Uh, is um,
• 4:24
  uh, the new Director General of the SKAO
• 4:27
  Observatory. Sorry, SKA Observatory. Anyway,
• 4:30
  yeah, also on the site in Western Australia
• 4:33
  is ascap, which is the
• 4:35
  Australian SKA
• 4:38
  Pathfinder. A s K a p.
• 4:41
  Coincidence.
• 4:43
  Andrew Dunkley: Uh, an ASCAP is also something you can wear
• 4:45
  if you don't have any pants.
• 4:50
  Professor Fred Watson: There's no answer to that, Andrew.
• 4:52
  Andrew Dunkley: Uh, no,
• 4:55
  no, that one. Can't we just let that one.
• 4:56
  Professor Fred Watson: No, I might leave that one alone. Yeah.
• 4:59
  Anyway, notwithstanding that.
• 5:02
  See, you don't get this on other podcasts, do
• 5:04
  you? It's why we're number one in Iceland.
• 5:07
  Andrew Dunkley: That's right, we are. Thank you.
• 5:10
  Iceland.
• 5:11
  Professor Fred Watson: Absolutely. Go for it. Um,
• 5:14
  I forgot. Yes. ASCAP,
• 5:17
  not the garment, but the um,
• 5:20
  Radio Telescope Array, 3612 metre
• 5:23
  dishes which were built um, over
• 5:25
  the. I guess 15 years ago was when they
• 5:28
  started. It's been operational for probably
• 5:30
  more than 10 years now and done some fabulous
• 5:33
  work. Uh, but the latest piece of high
• 5:36
  profile research that's come from ASCAP is
• 5:39
  exactly as you've said, the largest
• 5:41
  magnetic map of the universe ever produced,
• 5:44
  five times larger than all previous efforts
• 5:46
  combined. And it marks the beginning of a new
• 5:49
  generation of research into the field of
• 5:51
  intergalactic magnetism. And I'm reading
• 5:53
  there from the CSIRO news release,
• 5:56
  um, probably spot the hype but it's well
• 5:58
  deserved type as well and a, uh, well
• 6:01
  deserved kudos to the team leader Alec
• 6:03
  Thompson of csiro. Um,
• 6:06
  what they've done is used
• 6:08
  the telescope uh, in a, I
• 6:11
  suppose in an innovative way.
• 6:14
  Uh, how do you measure magnetic fields? Well
• 6:16
  you know normally to measure a magnetic field
• 6:18
  we stick uh, a magnetometer in the way.
• 6:21
  That's how magnetic fields are measured in
• 6:23
  the solar system by various spacecraft
• 6:25
  because they carry magnetometers which
• 6:27
  measure the local magnetic field of where you
• 6:29
  are. Um, and that gives us
• 6:32
  some insights into not just the sun's
• 6:35
  magnetic field, not the Earth's magnetic
• 6:36
  field and the sun's magnetic field, but also
• 6:39
  uh, courtesy of Voyager, the two Voyager
• 6:41
  spacecraft. The galaxy's magnetic field
• 6:44
  because we can sense the direction of that
• 6:46
  with the magnetometers uh, carried by those
• 6:49
  spacecraft which are now beyond the sun's
• 6:51
  magnetic influence. But
• 6:54
  uh, it's quite a long jump
• 6:57
  from the environs of the
• 7:00
  solar system to the universe as a whole,
• 7:03
  uh, which is what these scientists have done.
• 7:06
  And the basic technique
• 7:09
  is uh, it's all about
• 7:12
  um, polarisation and
• 7:15
  we've talked about polarisation before, we
• 7:18
  all know what it does when we
• 7:21
  wear our uh, polarising sunglasses and you're
• 7:23
  driving your car into the sunlight and
• 7:26
  there's a huge reflection coming off the
• 7:29
  road, especially if it's wet. Uh, and your
• 7:31
  polarising sunglasses magically take away
• 7:35
  that's happening because uh, the light waves
• 7:38
  uh, have um,
• 7:41
  if you think of them as just being wiggles in
• 7:43
  space, which they are, ah, electromagnetic
• 7:45
  wiggles, they have a preferred direction.
• 7:48
  Um, normal light has a mix of all these
• 7:51
  directions but uh, it turns out that
• 7:54
  you can separate out them by using
• 7:56
  well a polarising filter which is what we've
• 7:59
  got in our sunglasses that only lets through
• 8:01
  the vibrations that are vertical. That's the
• 8:04
  vertical direction of the light that's coming
• 8:06
  to you because the horizontal ones which are
• 8:10
  very um, much reflected uh,
• 8:14
  in the reflection from the wet road, they are
• 8:17
  cancelled out and so you don't see them. Uh,
• 8:21
  so we're kind of familiar with that idea of
• 8:24
  the direction of vibration of
• 8:26
  Light waves. Well, the same holds good
• 8:29
  in, um, in radio waves. And
• 8:32
  so ASCAP and many other radio
• 8:34
  telescopes can actually sense the
• 8:37
  polarisation of the radio
• 8:39
  signals that they're receiving from deep
• 8:41
  space. Uh, and so that's all
• 8:44
  well and good, you can sense the
• 8:46
  polarisation, but you can also
• 8:48
  detect if that polarisation's
• 8:51
  been twisted. And that's what happens
• 8:54
  when the light passes through a magnetic
• 8:56
  field. Um, it actually rotates,
• 8:59
  called Faraday rotation. It's the plane of
• 9:02
  the radio waves twists. And
• 9:05
  you can detect that with an array like
• 9:08
  ascap. And that is what has allowed
• 9:11
  people to measure the magnetic field of the
• 9:13
  universe. Because what you do
• 9:16
  is you look at, uh, the light from
• 9:19
  a distant galaxy and you look at the way
• 9:22
  its polarisation changes, uh, as that
• 9:25
  light comes towards us by using this
• 9:28
  technique. And so what you're saying is
• 9:31
  that you've got a kind of, um,
• 9:34
  a beacon lamp in the distance and
• 9:37
  what you can sense is what's happening to the
• 9:39
  light coming from that as it passes through
• 9:41
  magnetic fields on its way. And so
• 9:44
  that's the basis of the map, as
• 9:47
  far as I can tell from, because I'm not a
• 9:50
  radio astronomer, which is pain, the obvious,
• 9:52
  probably from the way I'm talking about it.
• 9:54
  Um, I think you probably
• 9:57
  don't know how far away that magnetic field
• 10:00
  is. And so, um, what you can
• 10:02
  infer is, uh,
• 10:06
  for example, how rapidly it changes, uh,
• 10:08
  depending on the position
• 10:11
  in the sky. Um,
• 10:15
  when you look at this map, and I urge our
• 10:17
  listeners to have a look at it, it's pretty
• 10:19
  easy to find and largest magnetic map of the
• 10:21
  universe yet. Um, you'll see lots of colours.
• 10:24
  Um, the colours, I think, are colour coded in
• 10:27
  that. I, um, think if I remember rightly,
• 10:29
  red is with the North Pole
• 10:32
  pointing towards us of the magnetism, and
• 10:35
  blue is it pointing the other way. Um,
• 10:38
  and so that, uh, lets you sense the
• 10:41
  magnetism along that line of sight. And so
• 10:44
  the biggest detail is actually in the
• 10:46
  galactic centre, which is full of churning
• 10:49
  magnetic fields. I guess you are having a
• 10:51
  look at it now.
• 10:52
  Andrew Dunkley: I'm looking at it right this minute. And
• 10:54
  yeah, you're right that they're explaining
• 10:56
  that just like, um, you've got blue shift and
• 10:58
  redshift with light waves, the magnetic
• 11:01
  fields have the same kind of qualities in
• 11:04
  terms of north, south, um, on the
• 11:07
  magnetic plane. And yes, the centre of the
• 11:09
  Milky Way galaxy is probably the most
• 11:11
  volatile part of this entire picture. Um,
• 11:14
  which is not surprising. We live there.
• 11:17
  Professor Fred Watson: That's right.
• 11:17
  Andrew Dunkley: We know all about volatility.
• 11:19
  Professor Fred Watson: Yeah. It's home from home.
• 11:21
  Uh, and just going back to, um, what
• 11:24
  you said a few minutes ago, um, there is a
• 11:27
  hole in the, uh, map. And
• 11:30
  that's because ascap, there's certainly
• 11:33
  regions of the northern sky that ASCAP can't
• 11:35
  see because they're permanently below the
• 11:37
  horizon. They're relatively small, actually,
• 11:38
  because ASCAP can look a long way down
• 11:41
  towards the horizon, much further than we
• 11:42
  can. In optical astronomy. In optical
• 11:45
  astronomy, the atmosphere just gets too thick
• 11:47
  when you're looking very low down until you
• 11:49
  get all the distortions and everything from
• 11:51
  the atmosphere. That doesn't happen, uh, with
• 11:53
  low frequency radio waves. Um,
• 11:56
  the gap that's missing because of the
• 11:58
  Northern Hemisphere, uh, because it's not
• 12:00
  visible to the telescope, that's actually
• 12:02
  relatively small compared with if it was an
• 12:04
  optical astronomy picture that you were
• 12:06
  looking at. But yes, this map has
• 12:09
  the line of the Milky Way across its equator,
• 12:11
  across the middle. Um, lots of magnetic
• 12:14
  turbulence in there, some really intriguing
• 12:17
  features, things that look like magnetic
• 12:19
  fingers just sort of pointing around. It's
• 12:22
  a remarkable map which, um, yeah, I encourage
• 12:24
  people to have a look at.
• 12:26
  Andrew Dunkley: Now, just by way of, um, taking this a step
• 12:29
  further. Uh, what can they now,
• 12:31
  or what can anybody now do with a map like
• 12:34
  this? Because it's been made publicly
• 12:36
  available, hasn't it?
• 12:37
  Professor Fred Watson: Yes, so that's exactly right. Those data, uh,
• 12:40
  are now publicly available. By the way, I
• 12:43
  do like the name of it, which is
• 12:45
  Spice.
• 12:46
  Andrew Dunkley: Spice Racks.
• 12:47
  Professor Fred Watson: Yeah. Uh, so Racks is
• 12:50
  the Rapid ASCAP Continuum Survey.
• 12:53
  And I've forgotten what Spice is, but it's
• 12:56
  something equally, equally delightful.
• 12:59
  Uh, but the Spice Racks Survey, I think is,
• 13:01
  uh, is. It's got its own, uh,
• 13:04
  own. Own charm about it.
• 13:06
  Andrew Dunkley: I was going to say something tongue in
• 13:09
  cheek about a girl group named Something to
• 13:11
  do with spice.
• 13:12
  Professor Fred Watson: Oh, yes, I know that.
• 13:14
  Andrew Dunkley: Then I thought, no, you can't really
• 13:16
  associate that with racks. You could get
• 13:17
  yourself smashed.
• 13:20
  Professor Fred Watson: I would leave that well alone. I will.
• 13:22
  Andrew Dunkley: I won't mention it.
• 13:23
  Professor Fred Watson: Yeah, so, um,
• 13:25
  it's. Yes, so it's so. And, and yes,
• 13:28
  as data are already publicly
• 13:31
  available, uh, research groups are already
• 13:35
  actually digging through this to see
• 13:37
  what it tells us about the, you know, the
• 13:40
  magnetism of galaxies, for a start.
• 13:42
  Professor Fred Watson: Uh,
• 13:44
  Professor Fred Watson: and just the way the environment of a galaxy
• 13:48
  is dominated by a particular magnetic field.
• 13:50
  It's only recently that we've understood
• 13:53
  that cosmic magnetic fields. That,
• 13:56
  uh, is magnetic fields in space play a huge
• 13:58
  role in so many areas of astrophysics,
• 14:01
  but certainly in the way galaxies evolve
• 14:04
  over the millennia. Millennia.
• 14:07
  I suppose they are uh, the way they evolve,
• 14:10
  uh, is, um, very much
• 14:13
  dominated by the local magnetic fields. And
• 14:16
  one of the big puzzles in cosmology, the
• 14:19
  science of the universe as a whole, is where
• 14:22
  did these magnetic fields come from in the
• 14:23
  first place? And it's actually
• 14:26
  one of the things on the list of target
• 14:29
  science. The Square Kilometre Array
• 14:32
  itself was designed to address what's the
• 14:35
  origin of the cosmic magnetic field, uh,
• 14:38
  because we really don't know how they came to
• 14:41
  exist. And more than that, we don't
• 14:44
  know how magnetic fields have changed as, you
• 14:46
  know, as the universe itself has evolved. All
• 14:49
  this lets you do that because, of course, as
• 14:51
  you look further out into space, you're
• 14:52
  looking further back in time. So there's a
• 14:55
  time dimension of this as well.
• 14:57
  Andrew Dunkley: Yeah, there's a lot of magnetism out there.
• 14:59
  And as you say, they don't know where it came
• 15:01
  from. Uh, we probably would have solved it
• 15:04
  except dark matter and dark energy came along
• 15:06
  and we went, oh, well, this is more exciting.
• 15:08
  But, um, yeah, it's just another one of those
• 15:10
  mysteries.
• 15:12
  Professor Fred Watson: It is. And I'm sure,
• 15:14
  um, all the scientists who've been involved
• 15:17
  with this have got magnetic personalities.
• 15:20
  Oh, sorry. I do my best.
• 15:23
  We aim to please.
• 15:24
  Andrew Dunkley: Pretty good, that one. All right. If you'd
• 15:26
  like to read up on it, you can do that
• 15:28
  through the scene. CSIRO website. It's an
• 15:30
  Australian website and you can download the
• 15:33
  map. It's only 6 million megabytes. It's
• 15:35
  a 6 megabytes. It's not a big file in the
• 15:38
  modern age. Uh, you can also read the
• 15:41
  paper in publications of the Astronomical
• 15:44
  Society of Australia. This is
• 15:47
  Space Nuts with Professor Fred Watson Watson
• 15:49
  and Andrew Dunkley.
• 15:55
  Space Nuts.
• 15:56
  Professor Fred Watson: All right. Um, now, you
• 15:59
  did press, didn't you?
• 16:01
  Andrew Dunkley: I did press record. Yes. Um, yes,
• 16:04
  the giant gap was a misfire.
• 16:06
  Professor Fred Watson: Oh, good. That's good.
• 16:07
  Andrew Dunkley: Okay, we get those.
• 16:09
  Uh, now our next storey, it's a, uh, new
• 16:12
  report about the relationship between
• 16:14
  black holes and dark matter. Now this is,
• 16:16
  this is something that our audience has quite
• 16:19
  often thrown up. You know, there's got to be
• 16:21
  a connection, uh, between black holes and
• 16:24
  dark matter, et cetera, et cetera. Uh,
• 16:27
  and now they've released a paper that's
• 16:29
  suggesting just that.
• 16:31
  Professor Fred Watson: Yes, this is really interesting stuff. And of
• 16:34
  course, um, it covers
• 16:37
  two of the most popular topics that we
• 16:40
  discuss on, uh, Spacenuts. This is
• 16:43
  research, uh, from Virginia Tech,
• 16:46
  uh, in the United States. And
• 16:49
  it's very neat because it uses a technique
• 16:51
  that I've always found absolutely
• 16:53
  fascinating, um, which
• 16:56
  is it's got A fancy name, uh,
• 16:59
  called reverberation mapping. Uh,
• 17:02
  but we usually talk about light echoes.
• 17:06
  Uh, and the easiest way to
• 17:08
  envisage it is, uh, the one that
• 17:11
  I think drew
• 17:13
  everybody's attention to this phenomenon back
• 17:16
  in the 1980s, uh, when
• 17:19
  supernova 1987A,
• 17:22
  the nearest supernova to us since
• 17:24
  Kepler's supernova in 1604, I think it was,
• 17:28
  um, that uh, became very much the object
• 17:30
  of attention. Uh, it was in the Large
• 17:32
  magellanic Cloud, to 165,000 light
• 17:35
  years away from us as the crow flies.
• 17:38
  And what was discovered as time
• 17:41
  went on was the. So that the
• 17:43
  supernova explodes. You've got this brilliant
• 17:46
  flash of light. It was easily visible to the
• 17:48
  naked eye. I remember looking at it. Uh,
• 17:51
  and uh, then as time goes by, the light
• 17:54
  fades. But what you get,
• 17:57
  uh, uh, as time goes on is a series of
• 18:00
  rings around the, apparently around
• 18:04
  the site of the explosion. And those
• 18:07
  rings are caused by light being
• 18:11
  reflected off clouds of dust which
• 18:13
  are between us and the supernova. And you
• 18:16
  can do all kinds of really neat calculations,
• 18:20
  uh, to discover how thick those clouds of
• 18:23
  dust are, where they are in relation to the
• 18:25
  supernova. Um, um, one of my
• 18:27
  colleagues, now sadly no longer with us,
• 18:30
  David Allen, was a past master,
• 18:32
  uh, about working on this and writing about
• 18:35
  it. And uh, those rings are called
• 18:37
  light echoes because it's the echo of the
• 18:39
  light of the supernova which has now faded
• 18:42
  away. But you can still see it because it's
• 18:44
  bouncing off clouds of dust in space.
• 18:48
  So, so what this article is
• 18:51
  about, the Virginia Tech work that we've just
• 18:53
  mentioned is we know that black
• 18:56
  holes, supermassive black holes, are
• 18:58
  surrounded by swirling discs of
• 19:01
  matter. Uh, they're called the accretion
• 19:04
  disc. It's the stuff that's basically
• 19:06
  swirling around the plug hole, um, before it
• 19:09
  either gets sucked into the black hole or
• 19:11
  shot out vertically from the poles of the
• 19:14
  black hole. The rotation poles it in the form
• 19:16
  of these jets, which we hear a lot about. But
• 19:18
  the accretion disc itself is bright,
• 19:21
  um, in X rays and radio radiation.
• 19:25
  Uh, once in a while, um, a
• 19:27
  larger dollop of matter enters the
• 19:30
  accretion disc. And you get this
• 19:32
  outburst, you get a brilliant outburst
• 19:36
  of radiation. Um, and
• 19:39
  that outburst is relatively short lived.
• 19:42
  It might last for a few weeks or even months,
• 19:44
  but it's short lived. And so what you can
• 19:47
  look for is a light echo
• 19:50
  around it. Because that light radiates
• 19:52
  outwards from the accretion disc. And if it
• 19:55
  hits anything outside it,
• 19:58
  it will reflect back to us. And we'll see it
• 20:01
  at a later date from when
• 20:04
  the bright event itself
• 20:06
  happened. So you see the bright event in the
• 20:09
  accretion disc and then at, uh, some time
• 20:11
  later you see an echo of that
• 20:14
  light which is being reflected off,
• 20:17
  usually gas and D which is surrounding,
• 20:20
  uh, the accretion disc. What this storey is
• 20:23
  all about though, is that, uh, when you do
• 20:25
  calculations about how
• 20:28
  much material there
• 20:31
  is in the accretion disc where the echo
• 20:34
  is taking place, you get a much
• 20:37
  higher mass than what you can see. And
• 20:39
  that's always the, um,
• 20:42
  that's always the um, uh, kind of
• 20:44
  telltale signature of dark matter
• 20:48
  when you can only see a limited, limited
• 20:50
  amount of stuff. But gravity tells you
• 20:53
  there's much more, there's more there. And
• 20:55
  that's exactly the basis of this storey. So
• 20:57
  it's just a new way of detecting
• 21:00
  the dark matter, uh, around
• 21:03
  black holes. But it looks as though black
• 21:06
  holes, as you'd expect, not only
• 21:09
  are a magnet for regular matter. I, uh,
• 21:12
  mean a gravitational magnet. I guess it's not
• 21:15
  magnetic in the sense that we've just been
• 21:16
  talking about, uh, but a gravitational,
• 21:19
  uh, pull from, for normal matter. It's also a
• 21:21
  gravitational pull for dark matter as
• 21:24
  well. And it looks as though the dark matter
• 21:26
  actually congregates around black holes that
• 21:29
  we've got, um, these buildups of dark
• 21:32
  matter, ah, in the vicinity of a black
• 21:34
  hole. Quite remarkable.
• 21:37
  Andrew Dunkley: Now, the situation is that they
• 21:39
  haven't absolutely proven it. They've
• 21:42
  just come up with a way of suggesting that
• 21:45
  this might be the case. But, um.
• 21:47
  Yeah, it's not absolute. It's not.
• 21:52
  Professor Fred Watson: It is in the sense that, um, they've looked
• 21:55
  at this for 14 different
• 21:57
  galaxies and all found
• 22:00
  cases where, uh,
• 22:03
  what you're looking for is the way the mass
• 22:06
  changes with distance from the black hole.
• 22:08
  And that mass is increasing because you're
• 22:11
  looking at stuff swirling around. But the
• 22:14
  increase in mass is faster
• 22:17
  than the visible matter on its own can
• 22:19
  explain. And that's the a. It's
• 22:22
  a kind of smoking gun for dark matter,
• 22:24
  really.
• 22:24
  Andrew Dunkley: Yeah, I, I've, I've found the paragraph. It
• 22:27
  says data limitations mean the results are a
• 22:30
  proof of concept, not a definitive,
• 22:32
  Definitive detection. Detection. But the
• 22:34
  study outlines a clear path to confirmation.
• 22:36
  Professor Fred Watson: That's right, yeah. So that.
• 22:37
  Andrew Dunkley: We're almost there.
• 22:38
  Professor Fred Watson: We're almost there. That's. That's exactly
• 22:40
  right. We're almost there.
• 22:41
  Andrew Dunkley: That is very exciting news. And, um, that
• 22:44
  will stop probably 75% of the questions we
• 22:47
  get on our Q A editions.
• 22:50
  Professor Fred Watson: Well, it, it might, but I Bet it produces
• 22:53
  another 150 about what it is that we're
• 22:56
  finding and how do we know why? Isn't it mond
• 22:58
  and things like that? Yeah.
• 23:00
  Andrew Dunkley: Yes. Oh gosh, it will just. It'll never end.
• 23:03
  It will never end. I hope it never ends.
• 23:05
  Professor Fred Watson: I think it's great.
• 23:07
  Andrew Dunkley: But if you want to read about it,
• 23:08
  it's@fizz.org uh, they publish the paper
• 23:11
  in the Physical Review D. Does that mean
• 23:14
  there's an A, B and C that comes with.
• 23:16
  Professor Fred Watson: Yes it does.
• 23:17
  Andrew Dunkley: I assume so.
• 23:18
  Professor Fred Watson: But um, that's a high profile journal though.
• 23:20
  Physical Review. It's uh, definitely uh,
• 23:24
  uh, you know it's, it's uh, ranks with Nature
• 23:26
  and Science and these very high profile
• 23:28
  journals. So it's not work that is
• 23:31
  in any way secondary. It's not like Space
• 23:34
  Nuts where it's adequate. This is top
• 23:38
  ranked stuff.
• 23:39
  Andrew Dunkley: Indeed it is. Uh, yes. So read about it
• 23:42
  at Physical review or@phys.org this is
• 23:45
  space Nuts. Andrew Dunkley here with
• 23:46
  Professor Fred Watson Watson.
• 23:51
  Professor Fred Watson: Okay, we checked all four systems.
• 23:54
  Professor Fred Watson: Space Nets.
• 23:56
  Andrew Dunkley: Our final storey. Fred Watson takes us
• 23:58
  into the realm of um,
• 24:01
  publicly offering your company up on the
• 24:04
  stock exchange.
• 24:05
  Professor Fred Watson: I wonder why we're going to talk about that.
• 24:07
  Andrew Dunkley: I wonder why uh, the world's first
• 24:09
  trillionaire has just done that in um, a
• 24:12
  very interesting way. And to coincide with
• 24:14
  the launch, um, he's selling stuff
• 24:17
  like we do on the Space Nuts shop. All
• 24:20
  sorts of little bits and bobs if you want a
• 24:23
  piece of the action.
• 24:24
  Professor Fred Watson: Yes, the IPO merch.
• 24:26
  Andrew Dunkley: It really is a remarkable storey though. Uh,
• 24:29
  elon Musk and SpaceX. Because uh,
• 24:32
  as this article briefly um, mentions,
• 24:35
  he didn't think the company would survive. He
• 24:37
  didn't expect it to actually be a success.
• 24:40
  He gave it a very low chance of lasting
• 24:43
  and look at him now.
• 24:46
  Professor Fred Watson: Quite so. The world's world first
• 24:48
  trillionaire. Ah yeah, it's um,
• 24:52
  I mean I don't honestly I know virtually
• 24:54
  nothing about the world of high finance.
• 24:57
  Andrew Dunkley: Um, well you know more than me then.
• 25:00
  Professor Fred Watson: When I see numbers like millions and
• 25:02
  billions, I always expect there to be light
• 25:04
  years after them rather than dollars.
• 25:07
  But yeah, it's uh, the, the public,
• 25:10
  the IPO initial public offering, um, has
• 25:13
  valued this company at uh, something
• 25:15
  absolutely huge. Compared with all the other
• 25:18
  tech companies that are being floated or are
• 25:20
  likely to be floated into public ownership.
• 25:23
  It's enormous. Um, is it
• 25:26
  170 billion? Am I thinking of the right
• 25:28
  number there or is that light years? That
• 25:30
  could be light years, I don't know.
• 25:33
  Anyway, um, the bottom line so, yes, that
• 25:35
  was, um, uh, over the weekend that
• 25:39
  m offering IPO
• 25:42
  happened, uh, and it was very successful.
• 25:45
  Um, I heard people on Friday saying, oh, no,
• 25:48
  it'll probably just fail because nobody will
• 25:50
  actually believe what Elon Musk's saying.
• 25:53
  Well, they might not have believed what he
• 25:55
  was saying, but they put their money where
• 25:56
  their mouths were. And um, yeah, so it's done
• 25:59
  very, very well. Um, I think the number
• 26:02
  I'm thinking of is $160.95,
• 26:05
  which is the share price.
• 26:07
  Andrew Dunkley: Well, I've just looked now and I know this is
• 26:09
  being recorded. So by the time people hear
• 26:11
  this, the number will change. But at the
• 26:13
  moment, at this very moment,
• 26:15
  $192.50 in US
• 26:18
  dollars.
• 26:18
  Professor Fred Watson: All right, so they've already gone up then.
• 26:21
  Andrew Dunkley: They've gone up 19.6%.
• 26:23
  Professor Fred Watson: Yeah.
• 26:24
  Andrew Dunkley: In fact, they're up 31.55% today.
• 26:27
  Professor Fred Watson: So not a bad investment really, if you're
• 26:29
  into that kind of thing. Yeah, well, we're
• 26:31
  not into that kind of thing, but we're
• 26:33
  definitely into merge. Uh, and that's what
• 26:35
  this storey's about because,
• 26:38
  um. Uh, I guess the one
• 26:41
  thing you can not accuse Elon
• 26:44
  Musk of is lacking flair, um,
• 26:47
  because he's done this very nicely. You can
• 26:49
  buy a mission patch,
• 26:52
  Professor Fred Watson: uh,
• 26:52
  Professor Fred Watson: for the ipo, uh, which says
• 26:55
  the future is public. There's a lovely
• 26:58
  embroidered starship in the
• 27:01
  background. Uh, in the middle it says
• 27:03
  SPCX, which is SpaceX liftoff
• 27:06
  underneath it. And, uh, SpaceX
• 27:08
  2026. Uh, and it's also got a four
• 27:11
  leaf clover on it, which I think is present
• 27:13
  on all Elon Musk. SpaceX.
• 27:16
  Andrew Dunkley: I think that's been his logo since day one.
• 27:18
  Professor Fred Watson: Yes. Yeah. M a sign of good luck.
• 27:21
  Maybe that's what's done it. But the thing I
• 27:24
  liked was, um, uh,
• 27:27
  you can have a souvenir bell.
• 27:30
  And I guess I don't know whether
• 27:33
  bells are normally associated. I know they're
• 27:35
  certainly associated with the stock exchange,
• 27:37
  but whether with, uh, public offerings,
• 27:40
  they're associated. But they certainly are in
• 27:42
  this case. And what he's chosen for the shape
• 27:44
  of his bell is something absolutely perfect.
• 27:46
  It's the bell, um, of,
• 27:49
  uh, a Raptor engine. These rocket
• 27:52
  motors have a very strongly bell shaped,
• 27:55
  uh, thrust chamber. I guess it's the, um,
• 27:58
  opening, uh, that lets all the gas out, uh,
• 28:01
  after it's been ignited in the combustion
• 28:04
  combustion chamber above it. And so it's a
• 28:05
  scale replica of the Raptor engines that
• 28:08
  actually power the Falcon
• 28:11
  Heavy, um. I beg your pardon, the super heavy
• 28:13
  Booster, which is the basis of starship.
• 28:16
  It's got 33 of these. And
• 28:19
  um, uh, this one's
• 28:22
  got a little clapper in the middle that lets
• 28:24
  you ring it as well as all the artwork. And
• 28:27
  apparently it rings. Yes, because there's a
• 28:28
  video on the website that shows you that, uh,
• 28:31
  they
• 28:32
  Andrew Dunkley: haven't released those yet to the
• 28:34
  public.
• 28:35
  Professor Fred Watson: That's right.
• 28:35
  Andrew Dunkley: They will be out probably. I think they're
• 28:37
  talking December. Yeah, um,
• 28:40
  yeah, they're sort of an 18 centimetre or
• 28:43
  7 inch scale model of the, the
• 28:45
  SpaceX Raptor Bell. This
• 28:48
  one has a, you know, clunker in it that makes
• 28:51
  it ring. I don't know what that thing's
• 28:53
  called inside the bell, the dinghy thing.
• 28:56
  Professor Fred Watson: It's a clapper, is it? That's the technical
• 28:59
  name. Yeah, for.
• 29:00
  Andrew Dunkley: Anyway, so they're selling those, they're
• 29:02
  selling, uh, tote bag and
• 29:05
  um, as you said, mission patches, T shirts,
• 29:08
  caps, you
• 29:11
  Professor Fred Watson: know, he's um, he's the sort of
• 29:13
  Andrew Dunkley: bloke that never lets opportunity get away.
• 29:15
  Professor Fred Watson: None whatsoever. I, I did hear
• 29:19
  some of the things that he said publicly at
• 29:22
  the launch which made me cringe,
• 29:25
  uh, because,
• 29:28
  you know, I can, I can, can just about,
• 29:32
  um, believe that we
• 29:34
  might get humans to Mars in his lifetime.
• 29:38
  It won't be millions. And that's because
• 29:41
  that's immoral, apart from anything else.
• 29:44
  Um, but he was talking about,
• 29:47
  uh, you know, flying through,
• 29:50
  around the solar system and beyond.
• 29:54
  And at the moment that is off
• 29:57
  the agenda. Physics doesn't let you do
• 30:00
  that.
• 30:01
  Uh, just actually as a little footnote to
• 30:03
  that, I read a paper yesterday, uh, which
• 30:06
  is about, you know, the idea of
• 30:09
  using, um, photonic
• 30:12
  propulsion, or basically light, Ah,
• 30:14
  energy blasted at a light sail. You've got a
• 30:17
  laser, uh, you fire it at this light sail and
• 30:20
  the spacecraft accelerates because of that.
• 30:22
  That's all fine and dandy and will work,
• 30:25
  um, if you can make your spacecraft light
• 30:27
  enough. But it turns out that you're not ever
• 30:29
  going to get near the speed of light
• 30:32
  beyond about 75% of the speed of light.
• 30:35
  You, uh, get something called relativistic
• 30:37
  drag, uh, where space itself drags on the
• 30:40
  light sail as well as any kind of
• 30:42
  interstellar matter that you've got to plough
• 30:45
  through at 75% of the speed of light.
• 30:47
  So that's not going to get us touring around
• 30:50
  the galaxy.
• 30:51
  Andrew Dunkley: No, we'll have to find another way.
• 30:52
  Professor Fred Watson: Need another way? Yes.
• 30:54
  Andrew Dunkley: They need to go to science fiction, um,
• 30:56
  writers and see what they've come up with.
• 30:59
  Professor Fred Watson: Maybe that's what Elon's thinking of. Maybe
• 31:01
  he was suddenly in the realm of science
• 31:03
  fiction, but he didn't bother to tell us.
• 31:05
  Andrew Dunkley: No, maybe not, no. But there's no, Nothing
• 31:08
  fictional about his, um, ip.
• 31:11
  Professor Fred Watson: No, not at all.
• 31:12
  Andrew Dunkley: Uh, initial public offering that is out there
• 31:14
  and it is going gangbusters. It's burning
• 31:17
  like a raptor at the moment.
• 31:20
  Professor Fred Watson: Yeah, probably will. I mean, you know,
• 31:23
  you've got to give the guy credit. Uh,
• 31:26
  two of the biggest breakthroughs of our, of
• 31:28
  our generation, huh? Electric vehicles
• 31:31
  and, um, reusable booster rockets. And
• 31:34
  basically they've come from him.
• 31:35
  Andrew Dunkley: Yes, they have. It's quite
• 31:38
  extraordinary. Yeah, you can read about it at
• 31:41
  collectspace. Uh, dot com. We, um,
• 31:44
  won't tell you all the prices of everything
• 31:46
  he's selling because that's, you know, you go
• 31:48
  and have a look. Um,
• 31:51
  totally your call. Um, but I do like the
• 31:54
  idea of mission patches and I'm pretty sure I
• 31:56
  suggested that to Huw many years ago that we
• 31:59
  should have mission patches.
• 32:01
  Professor Fred Watson: Yes, yes, we do.
• 32:02
  Andrew Dunkley: Yes. I've got something we should. A new one
• 32:05
  for every episode.
• 32:07
  Professor Fred Watson: Oh, all right. Okay.
• 32:09
  Andrew Dunkley: No, that's a bit much.
• 32:10
  Professor Fred Watson: Look, the trouble is the mission patches,
• 32:12
  they would just be adequate and if you.
• 32:15
  Andrew Dunkley: Although, I think, ah, our logo would make a
• 32:17
  great patch.
• 32:19
  Professor Fred Watson: It would. Yeah.
• 32:20
  Professor Fred Watson: Yeah.
• 32:21
  Andrew Dunkley: Anyway, um, we'll, we'll do that one day
• 32:24
  maybe. I don't know. There's plenty of other
• 32:25
  stuff in the shop. Just go and have a look in
• 32:27
  our shop. It's on our website.
• 32:28
  Spacenutspodcast.com or
• 32:31
  spacenuts IO uh,
• 32:33
  click on the shop link and buy yourself a
• 32:35
  pair of socks or a notebook or a,
• 32:38
  um, or a coffee cup or a hat or a
• 32:41
  hoodie, stickers. Um,
• 32:44
  there's just all this great stuff there. I've
• 32:46
  got some of it. Look, I've got my car cup
• 32:48
  here. See, here's my cup.
• 32:50
  Professor Fred Watson: Oh, that's nice. Yeah, I might
• 32:53
  have one of those somewhere.
• 32:54
  Andrew Dunkley: I probably do, yes. And I've got the tote
• 32:57
  bag as well. So we thought of that before
• 33:00
  Elon. Probably using the same company that
• 33:03
  we do. But
• 33:06
  yes. Um, I think that brings us to the end.
• 33:08
  Fred Watson, thank you so much.
• 33:10
  Professor Fred Watson: A pleasure, Andrew, good to talk. And we'll
• 33:12
  speak again.
• 33:14
  Andrew Dunkley: We will indeed.
• 33:15
  Professor Fred Watson Watson, astronomer at
• 33:17
  large, and thanks to Huw in the studio,
• 33:18
  couldn't be with us today because he wants to
• 33:20
  be the world's second trillionaire and he's
• 33:23
  just put down five bucks and he's just
• 33:25
  watching to see what happens. And from me,
• 33:27
  Andrew Dunkley, thanks for your company.
• 33:28
  We'll see you on the next episode of Space
• 33:30
  Nuts.
• 33:31
  Professor Fred Watson: Bye. Bye.
• 33:33
  Andrew Dunkley: You've been listening to the Space Nuts
• 33:35
  podcast, available at
• 33:38
  Apple Podcasts, Spotify,
• 33:40
  iHeartRadio or your favourite podcast
• 33:43
  player. You can also stream on
• 33:44
  demand@bytes.com this has been another
• 33:47
  quality podcast production from
• 33:49
  bytes.com.