Latest / Space Nuts: Astronomy Insights & Cosmic Discoveries / The Intricacies of Angular Momentum - What Happens Near Black Holes

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The Intricacies of Angular Momentum - What Happens Near Black Holes · Space Nuts: Astronomy Insights & Cosmic Discoveries

• 0:00
  Andrew Dunkley: Hi there. Thanks again for joining us. This
• 0:02
  is Space Nuts. It's a Q and A edition where
• 0:04
  we answer audience questions. And,
• 0:07
  uh, we. I think we've got our very first
• 0:10
  question from Yemen. Uh, Hussein
• 0:12
  has sent, uh, it a question asking about
• 0:15
  radial velocity. Uh, Martin, one of
• 0:18
  our regular contributors, has a dark matter
• 0:20
  he wants to discuss. Uh, Peter
• 0:23
  in Sweden is talking angular momentum.
• 0:26
  Uh, that is the angular momentum of matter
• 0:29
  falling into a black hole. And a
• 0:32
  real bummer of a question. We'll tell you all
• 0:34
  about it on this episode of space
• 0:37
  nuts.
• 0:38
  Professor Fred Watson: 15 seconds. Guidance is internal.
• 0:40
  10, 9.
• 0:42
  Ignition sequence start. Space nuts.
• 0:45
  Berman Gorvine: 5, 4, 3, 2.
• 0:46
  Professor Fred Watson: 1, 2, 3, 4, 5, 5, 4, 3,
• 0:49
  2, 1.
• 0:50
  Andrew Dunkley: Space nuts.
• 0:51
  Professor Fred Watson: Astronauts report it feels good.
• 0:54
  Andrew Dunkley: And he's back again to solve all your
• 0:56
  riddles. It's Professor Fred Watson Watson,
• 0:58
  astronomer at large. Hello, Fred Watson.
• 1:01
  Professor Fred Watson: Hello, Andrew. Good to see you again. I
• 1:03
  always hoped we'd get back together again one
• 1:05
  day and here we've been ages.
• 1:09
  Andrew Dunkley: About two minutes. Uh, yeah.
• 1:12
  Um, anyway, I love the
• 1:15
  Q and A programme, I really do, because it
• 1:17
  gives people a chance to, um, dump on us
• 1:20
  and see how much we can mess it up. And
• 1:23
  that's always fun. Um, we might
• 1:26
  get straight into it. Fred Watson and
• 1:29
  I was very excited to see that. We've got a
• 1:31
  question from Yemen. I never thought we. I
• 1:34
  didn't even know we were heard in Yemen,
• 1:37
  so that's really fantastic. And,
• 1:39
  um, this one comes from Hussain, who says,
• 1:42
  I'm a huge fan of the podcast Calling in from
• 1:44
  Yemen. See, I was right. It was Yemen. Ah,
• 1:47
  First, a quick confession. I hope you're not
• 1:48
  offended, but Space Nuts is my absolute
• 1:51
  favourite show to listen to when I'm falling
• 1:53
  asleep.
• 1:57
  Your voices are incredibly soothing. Uh,
• 1:59
  though I promise I do actually listen to the
• 2:02
  science before I drift off. I
• 2:04
  appreciate that. Um, my wife says I keep
• 2:07
  her awake, um, because I snore, but
• 2:10
  I don't believe it. I've never heard me. Uh,
• 2:12
  my question is about the radial velocity
• 2:15
  method for detecting exoplanets. I understand
• 2:17
  that a star wobbles because of the
• 2:19
  gravitational pull of its orbiting planets.
• 2:22
  However, how do astronomers use this
• 2:25
  method to isolate individual planets? For
• 2:27
  example, our sun must wobble because Mercury,
• 2:30
  Venus, Earth, Mars, Jupiter and the rest pull
• 2:33
  in different directions at the same time. If
• 2:35
  an alien astronomer were looking at our
• 2:38
  sun's wobble from across the galaxy, would
• 2:40
  they actually be able to untangle that
• 2:43
  messy combined signal to
• 2:45
  identify individual planets and their
• 2:48
  specific characteristics?
• 2:50
  Or does the wobble method just tell us, hey,
• 2:53
  there are planets here, without giving away
• 2:55
  the exact Details of who's who. Love
• 2:58
  the show. Keep up the fantastic work,
• 3:00
  Hussein. That's a really well crafted
• 3:02
  question. Thank you, Hussain.
• 3:05
  Professor Fred Watson: It is a great question as well. Uh, and
• 3:08
  the answer in a way is both.
• 3:11
  Um, the two alternatives that
• 3:14
  Hussein's put forward, uh, can you
• 3:16
  disentangle them or does the wobble method
• 3:18
  just tell us, hey, there are planets there,
• 3:21
  without giving away the exact details and
• 3:24
  what differentiates
• 3:26
  between them is first of
• 3:29
  all how bright the star is, how near it is.
• 3:32
  So what kind of strength of signal you get in
• 3:35
  terms of measuring the velocity of the star
• 3:37
  itself by this Doppler wobble method,
• 3:40
  uh, to analyse for planets. But also it
• 3:43
  depends on the sizes of the planets
• 3:46
  and on their mix, uh, as well.
• 3:49
  Um, so, uh, just thinking about
• 3:52
  the solar system, we've got the biggest
• 3:55
  planet, Jupiter. That's the one that has by
• 3:58
  far the biggest effect on the sun.
• 4:00
  Saturn comes next, uh, in terms of its
• 4:03
  size. And then the other two, uh, gas giants,
• 4:06
  uh, uh, Uranus and Neptune, uh,
• 4:10
  the terrestrial planets or rocky planets
• 4:13
  also have an effect. Uh,
• 4:16
  but because their masses are much lower, the
• 4:19
  effect is also much lower.
• 4:21
  It's mitigated slightly by by the fact that
• 4:23
  they're nearer to the sun, uh, but
• 4:26
  nevertheless they're much, much weaker than
• 4:28
  the gas giants. So if you were, uh,
• 4:31
  uh, an alien on a planet,
• 4:33
  uh, orbiting a star maybe eight or nine light
• 4:36
  years away, something like that, which is the
• 4:38
  distance to Sirius, uh, the brightest star in
• 4:41
  the sky, and you're looking back at the solar
• 4:43
  system, uh, the first thing you
• 4:46
  would see would be, uh,
• 4:48
  the main motion which would be due
• 4:51
  to Jupiter because its mass is so much
• 4:54
  bigger. The other planets, however,
• 4:57
  if you had really highly
• 5:00
  accurate velocity measurements and
• 5:03
  you'd need them almost to
• 5:05
  centimetres per second accuracy, uh,
• 5:08
  it can be done. Uh, there are ways of
• 5:10
  calibrating spectrographs to let you do this.
• 5:13
  Uh, but if you did have these really accurate
• 5:16
  readings and you could do
• 5:19
  your measurements almost 24 7,
• 5:22
  which you can't because, uh, certainly if
• 5:24
  we're anything like the Earth, you've got
• 5:26
  daylight coming in the way. Uh, but what
• 5:29
  you want to do is fill in the time domain as
• 5:32
  full as you can to get as many data
• 5:34
  points as you can, then what you would
• 5:37
  do, you'd build up a picture which would
• 5:40
  be dominated by Jupiter. But the
• 5:43
  graph of the speed of the star,
• 5:46
  the wobble of the star would have little ups
• 5:49
  and downs in it caused by the
• 5:52
  other planets. Uh, and you
• 5:54
  can disentangle those. There is
• 5:57
  a technique called Fourier analysis,
• 6:01
  uh, it uses, uh, things that we call fast
• 6:04
  Fourier transforms, which is a mathematical
• 6:07
  tool that um, kind of dates
• 6:10
  from the early days of computing, in fact,
• 6:12
  well before that when people did their
• 6:13
  calculations by hand. But for this, it's a
• 6:16
  way of disentangling just how many,
• 6:19
  what we might call periodicities, in other
• 6:21
  words, how many regular, um, passages
• 6:24
  are there, ah, caused
• 6:27
  by individual planets, if I can put it that
• 6:29
  way.
• 6:30
  So you can tease out the effect of
• 6:33
  each individual planet because they all have
• 6:35
  different periods of revolution, uh,
• 6:37
  around the sun. In the case of, if
• 6:40
  you're looking at the solar system. So, um,
• 6:43
  if you've got good enough data, you can uh,
• 6:46
  as Hussein suggests, uh, identify
• 6:49
  the individual planets and their specific
• 6:51
  characteristics. But if your data aren't so
• 6:53
  good, then you're basically just seeing the
• 6:56
  biggest ones of them. And that's just telling
• 6:58
  you that there's at least one planet there.
• 7:01
  Andrew Dunkley: Yeah, early on when we started discovering
• 7:04
  uh, exoplanets, we were only finding the big
• 7:07
  ones, weren't we? We assumed there were small
• 7:09
  ones, but it took us a long time to find the
• 7:12
  first one, didn't it?
• 7:13
  Professor Fred Watson: That's right. And in fact, um,
• 7:16
  it highlights the uh, the
• 7:19
  deficiencies of the Doppler wobble method,
• 7:21
  what Hussain was talking about as a way to
• 7:23
  discover planets, because it's really,
• 7:27
  that's most sensitive to the biggest ones.
• 7:30
  Uh, it was when the Kepler spacecraft,
• 7:33
  uh, and uh, Tess, the
• 7:36
  other, um, planet finding spacecraft, when
• 7:39
  they started looking in detail at the way the
• 7:42
  brightness of stars changed, uh, as
• 7:45
  planets passed in front of their parent
• 7:47
  stars. Uh, that's when we
• 7:50
  started discovering the smaller ones because
• 7:52
  the smaller ones are actually, uh, easier
• 7:55
  to discover that way.
• 7:57
  Andrew Dunkley: Um, here's a dumb question.
• 8:01
  Can we, can,
• 8:04
  can we look with accuracy at
• 8:07
  the wobble of our own sun because of
• 8:10
  the planets surrounding it, including our
• 8:12
  own?
• 8:13
  Professor Fred Watson: Yeah, uh, you can, yes.
• 8:16
  Um, and um, you
• 8:19
  can actually find, um, uh,
• 8:21
  diagrams showing the way.
• 8:26
  It's what we call the barycenter. The
• 8:28
  barycenter of the solar system is its
• 8:30
  centre of gravity, which takes into account
• 8:33
  not just the sun, uh, but the planets
• 8:36
  as well. And the barycenter does wander
• 8:38
  around. Uh, mostly it's inside
• 8:41
  the sun. It does come outside the sun
• 8:44
  from time to time. Uh, but uh, you can
• 8:47
  find charts showing exactly how that happens.
• 8:50
  Uh, you know, little maps of the way the
• 8:51
  barycentra of the solar system wanders around
• 8:54
  relative to the sun.
• 8:57
  Berman Gorvine: Okay.
• 8:57
  Andrew Dunkley: I wondered, I didn't know if we
• 9:00
  could do it within our own sphere. So to
• 9:03
  speak.
• 9:04
  Professor Fred Watson: Not a dumb question at all. Absolutely.
• 9:05
  Andrew Dunkley: There you go. I occasionally ask one that's
• 9:08
  adequate. Uh, and uh, thank you
• 9:11
  to Hussain for sending that question in from
• 9:14
  Yemen. Lovely to hear from you. And you're
• 9:16
  listening to SpaceNuts with Andrew Dunkley
• 9:18
  and Professor Fred Watson Watson.
• 9:21
  Let's take a quick break from the show to
• 9:23
  tell you about our sponsor, NordVPN.
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  spacenuts and don't forget the code word
• 11:00
  Space Nuts.
• 11:02
  Professor Fred Watson: I'm going to step off the land now.
• 11:06
  That's one small step for man.
• 11:11
  Berman Gorvine: One
• 11:14
  Berman Gorvine: Space Nuts.
• 11:16
  Andrew Dunkley: Let's hit uh, you with an audio question from
• 11:18
  one of our regular contributors.
• 11:21
  Berman Gorvine: Hello, Space Nuts.
• 11:24
  Martin Berman Gorvine here from
• 11:27
  Potomac, Maryland, usa,
• 11:31
  writer extraordinaire in many
• 11:34
  genres. With a
• 11:37
  slightly less silly, though
• 11:40
  still highly
• 11:42
  speculative question.
• 11:46
  Since dark energy is
• 11:49
  thought to pervade the entire
• 11:52
  universe, would it
• 11:55
  be possible, at least in
• 11:58
  theory, to harness that energy
• 12:02
  to drive space flight? And
• 12:05
  if so, uh, could you make
• 12:08
  a spacecraft go arbitrarily
• 12:11
  fast? By that means, you
• 12:14
  know, 99 point a whole bunch of
• 12:17
  nines percent of
• 12:19
  uh, the Speed of light for
• 12:22
  that extra relativistic
• 12:25
  Philip. So that when you
• 12:29
  step out at your destination,
• 12:32
  the uh, universe has aged
• 12:35
  significantly, but you,
• 12:38
  the traveller, have not.
• 12:41
  Can't wait for the
• 12:44
  answer. Which will probably involve
• 12:47
  Professor Watson shooting me down in
• 12:50
  flames as usual. Berman
• 12:53
  Gorvine, over and
• 12:56
  out.
• 12:57
  Andrew Dunkley: Thanks, Martin. Martin sent me a couple
• 13:00
  copy, uh, of uh, two of his latest books
• 13:02
  which I haven't had a chance to, to read and
• 13:05
  I did promise I would but um, uh, I was too
• 13:07
  busy writing my own. So, uh,
• 13:10
  um, but I will get to the.
• 13:12
  Martin, thanks for sending those in. Uh, fire
• 13:14
  away, Fred Watson.
• 13:17
  Professor Fred Watson: To shoot him down. Uh, I have to say these
• 13:20
  um, these questions do sound like the making
• 13:23
  of another of Martin's books.
• 13:26
  Uh, so, uh, you know, putting
• 13:29
  the ingredients uh, of um,
• 13:31
  science into the books. It's a great idea if
• 13:33
  you're going to write science fiction. It's
• 13:35
  nice to have some science in it as well.
• 13:37
  Um, yes you do. Um,
• 13:41
  what Martin's question made me think about
• 13:45
  was, um, the number of
• 13:48
  joules of energy contained,
• 13:51
  represented by dark energy per
• 13:54
  cubic metre of space.
• 13:57
  And I've no idea what that is, but I bet per
• 13:59
  cubic metre it's actually quite small,
• 14:03
  uh, because um, we only
• 14:06
  see the effect of dark energy when we look at
• 14:08
  the universe on a very large scale. When we
• 14:11
  look, you know, billions of light years out,
• 14:14
  we start to see its effects. We can
• 14:17
  tell that the universe has been expanding
• 14:19
  more rapidly, uh, since the universe was
• 14:21
  about half its present age. Uh,
• 14:24
  so I guess, you know, if you imagine
• 14:27
  a tank full of dark energy,
• 14:30
  uh, on any kind of human scale,
• 14:33
  whether it's the size of a, I don't know, you
• 14:35
  know, the size of the fuel tank on your car
• 14:37
  or the size of the average supertanker,
• 14:40
  um, my guess is that the amount of energy
• 14:42
  that, that would cont would actually be
• 14:45
  quite small. Um, I'm um, happy to be
• 14:48
  shot down on that, but I think it would
• 14:50
  simply because you're looking at uh,
• 14:53
  um, almost an infinitesimally small
• 14:56
  volume compared with the volumes that we
• 14:58
  think about when we're talking about the
• 15:00
  expansion of the universe and the accelerated
• 15:02
  expansion of the universe. So,
• 15:04
  um, how do you bottle it? Well, good
• 15:07
  question. Uh, that's the first thing
• 15:10
  you've got to do is find a way of extracting
• 15:12
  dark energy from space, putting it in a tank.
• 15:15
  But you might that if you do that on any kind
• 15:18
  of conceivable scale, you don't have enough
• 15:20
  to make any difference whatsoever to your
• 15:22
  spacecraft, let alone accelerate it to
• 15:25
  99.99999999% of the
• 15:28
  speed of light. So, um, I hope
• 15:31
  that's, uh, suitably satisfactory. Shooting
• 15:33
  down, Martin.
• 15:35
  Uh, I don't always shoot your theories down.
• 15:37
  I think your, uh, ideas are uh, lovely and
• 15:40
  well worth listening to.
• 15:42
  Andrew Dunkley: Yes, he's got a way, he's got a way of asking
• 15:45
  questions that he does. Lots of, Lots of fun.
• 15:48
  Lots of fun.
• 15:48
  Professor Fred Watson: He does.
• 15:49
  Andrew Dunkley: Uh, thank you, Martin. Um, we've got some
• 15:52
  live listeners, uh, uh, or viewers,
• 15:55
  um, who messaged us. And remember, uh,
• 15:57
  James from Cincinnati. Haven't heard from
• 15:59
  James in ages. Well, he's just popped up to
• 16:01
  say hello.
• 16:02
  Professor Fred Watson: So.
• 16:02
  Andrew Dunkley: Hi James. And uh, a question without
• 16:04
  notice, um, which sort of goes back to our
• 16:07
  radial velocity message method of searching
• 16:09
  for exoplanets. Um, I'm wondering,
• 16:11
  um, so we already know other suns have
• 16:14
  planets, so why the extensive investigation
• 16:16
  to keep searching for more? What's the point?
• 16:20
  Professor Fred Watson: Oh, it's a good question. Um, so it's all
• 16:23
  about, it's surveying. Um, basically,
• 16:26
  uh, astronomers are, uh, inveterate
• 16:29
  surveyors. It's how we discover
• 16:31
  the large scale characteristics of the
• 16:34
  universe. And it's also how we find the
• 16:37
  outliers, the things that are really
• 16:38
  peculiar, uh, and that need
• 16:41
  explanation and that sometimes defy science
• 16:44
  as we know it and um, often result in
• 16:47
  physics being rewritten. Uh, so,
• 16:51
  uh, it's
• 16:54
  like doing population census studies. It's.
• 16:57
  Why do you want to know how many people, uh,
• 16:59
  live in a country? And it's all about,
• 17:02
  um. Well, in the case of humans, it's all
• 17:04
  about providing the right resources for them.
• 17:07
  But in the case of.
• 17:10
  Why do you want to know how many different
• 17:11
  kinds of exoplanets there are? It's uh,
• 17:14
  because we might find exactly what we've just
• 17:16
  been talking about. The water worlds. Uh, we
• 17:18
  might find habitable worlds. We might even
• 17:20
  find a SETI signal from one of them. So,
• 17:23
  uh, this is very much an important part of
• 17:26
  the astronomers understanding of the
• 17:28
  universe. To explore and
• 17:31
  investigate as many of these things as we
• 17:33
  can.
• 17:34
  Andrew Dunkley: Yeah. And of course, the most important
• 17:35
  reason, if we do a planetary census,
• 17:38
  we can then introduce an international tax
• 17:41
  system system or intergalactic tax system,
• 17:44
  more to the point. Yes.
• 17:47
  Okay. Uh, you are listening to a Q and A
• 17:50
  edition of Space Nuts with Andrew Dunkley and
• 17:52
  Professor Fred Watson Watson.
• 17:57
  Professor Fred Watson: Three, two, one.
• 18:00
  Andrew Dunkley: Space Nuts. Our next question comes from
• 18:03
  Svedon. Uh, can matter
• 18:06
  that falls into a black hole keep its angular
• 18:09
  momentum and sort of add it to
• 18:11
  the black hole's angular momentum? Uh,
• 18:14
  or does matter Fall into a black hole.
• 18:17
  Um, or does matter falling into a
• 18:20
  black hole need to shed its angular momentum,
• 18:22
  or part of it through radiating, uh, energy
• 18:25
  out into space before it can fall down the
• 18:28
  hole? If so, why can't a black
• 18:31
  hole that can retain light and
• 18:34
  spaghettify things pull things in despite
• 18:37
  their angular momentum and just add the
• 18:39
  incoming momentum to itself? That comes from
• 18:42
  Peter in Sweden.
• 18:45
  Uh, it's one of those complicated questions
• 18:48
  that would have wiped me out at school
• 18:50
  based on some form of geometry.
• 18:56
  Professor Fred Watson: Uh, I am, um. So I
• 18:59
  don't know the answer to this question. Um,
• 19:02
  but thinking what little I do know
• 19:05
  about black holes, I would guess. Um,
• 19:07
  and I'll need to cheque this, Peter. So I
• 19:10
  apologise that this is an off the cuff
• 19:12
  answer. But I would guess that the angular
• 19:14
  momentum does. That it is
• 19:17
  additive. Uh, that you would add the
• 19:20
  angular momentum of incoming accreted
• 19:22
  material which will have it because it's
• 19:24
  whizzing around the black hole at very high
• 19:26
  speeds. Um, uh, as the black
• 19:29
  hole collapse, as the stuff crosses the event
• 19:32
  horizon and is subsumed into the black hole,
• 19:35
  uh, I would guess that actually adds to the,
• 19:37
  to the black hole's angular momentum. But
• 19:40
  I'll need to cheque. Uh, and I will do that
• 19:42
  because that's a really good question.
• 19:44
  Andrew Dunkley: Okay. Well, that was easy.
• 19:46
  Professor Fred Watson: Yeah, well, it wasn't because I don't know
• 19:48
  the answer, but. But I'm guessing I,
• 19:51
  uh, I think it probably would. Yeah.
• 19:53
  Andrew Dunkley: Actually reminds me, we had one we had to do
• 19:56
  some homework on recently and I think we've.
• 19:59
  I don't know if we did it. Anyway, I'll go.
• 20:01
  Professor Fred Watson: I usually make it. Yeah, I usually make notes
• 20:04
  on things like that as well. I think you're
• 20:06
  right too.
• 20:07
  Andrew Dunkley: Yeah. I might do a whole show on
• 20:11
  Professor Fred Watson: things we've forgotten.
• 20:13
  Andrew Dunkley: Things we've forgotten to look up.
• 20:15
  Professor Fred Watson: Yeah, yeah.
• 20:16
  Andrew Dunkley: Um, we might get back to you, Peter.
• 20:19
  Uh, thanks for the question. Um, this
• 20:22
  question. This question needs
• 20:25
  setting up because, uh, it's a question,
• 20:28
  but it's not a question. Uh, and it comes
• 20:30
  from, uh, Dave. Now, I know people have
• 20:33
  accidentally called me Dave from time to
• 20:35
  time. It's nice to have a real Dave. And
• 20:38
  when I read your question, Dave, I thought, I
• 20:40
  can't just let you go. I've got
• 20:43
  to, um, preempt it with something that I
• 20:46
  thought was appropriate.
• 20:48
  Professor Fred Watson: Hello, Dave. You're looking well
• 20:51
  today.
• 20:53
  Andrew Dunkley: Um, this is Dave.
• 20:56
  Berman Gorvine: Greetings. This is Dave from Gilbert,
• 20:58
  Arizona, with apologies in advance for my
• 21:01
  question. So anyway, I don't know if you, uh,
• 21:04
  heard about this, but, um, it's been reported
• 21:06
  that there's something strange in the region
• 21:08
  of our solar system somewhere between Saturn
• 21:10
  and Neptune. And I wanted to hear your
• 21:13
  opinion on the notion that it could be a
• 21:15
  black hole or a brown dwarf, or possibly a
• 21:18
  black dwarf or a brown hole out near the
• 21:20
  orbit of Uranus. So, by
• 21:23
  the way, uh, some people in the US Government
• 21:25
  have pooh, poohed this idea, while others
• 21:27
  from the US Military, such as Colin Powell
• 21:30
  and several rear admirals, are calling for a
• 21:33
  probe so we can get to the bottom of this.
• 21:36
  Now, I was wondering if you can get behind
• 21:38
  this notion or if you care to rebut it.
• 21:40
  In either case, I'm looking forward to
• 21:42
  hearing your posterior analysis.
• 21:45
  Uh, I also have a question about. Dang
• 21:47
  it, I gotta go. That's my landlord calling. I
• 21:49
  must be in arrears again on my rent. I'll
• 21:52
  have to call you back later with my question,
• 21:54
  super massive dark matter. Although that
• 21:57
  may actually be more of a medical question.
• 21:59
  Anyway, I wanted to say that your podcast is
• 22:01
  a real asset to the astronomical community.
• 22:04
  No ifs, ifs, ands, or buts about that. So
• 22:07
  cheers to you. Slash. Bottoms up.
• 22:11
  Andrew Dunkley: Ah, that's very clever, Dave. Um, I
• 22:14
  don't think we've ever had. You ready for
• 22:15
  this one, Fred Watson? I don't think we've
• 22:17
  ever had such an asinine
• 22:20
  question.
• 22:23
  Professor Fred Watson: Uh, yeah, it's, um. It's got
• 22:26
  every buzzword in the dictionary in there,
• 22:28
  hasn't it?
• 22:29
  Andrew Dunkley: It sure has.
• 22:30
  Professor Fred Watson: Especially the no if so. But I like that. I
• 22:32
  loved it. I loved it.
• 22:34
  Andrew Dunkley: Well done, Dave. I like that he spent
• 22:37
  time thinking about that and. And come up
• 22:39
  with. Yeah, all those
• 22:42
  superlatives.
• 22:43
  Professor Fred Watson: It's very, very well done. Um, my
• 22:46
  answer to it is, uh, yes,
• 22:49
  accreted material does add to the
• 22:51
  angular momentum of a black hole.
• 22:53
  Andrew Dunkley: Oh, you looked it up?
• 22:55
  Professor Fred Watson: I looked it up well, while I was enjoying
• 22:57
  Dave's question, because I know, having heard
• 23:00
  it before, that I didn't have to provide an
• 23:02
  answer to that.
• 23:04
  Andrew Dunkley: Yeah, actually, the live audience thought
• 23:06
  that was brilliant, too. We've got some very
• 23:08
  good remarks about it.
• 23:10
  Professor Fred Watson: So. Yeah.
• 23:10
  Andrew Dunkley: And another question, without notice,
• 23:12
  Fred Watson,
• 23:15
  when AI first came along,
• 23:19
  um, the. The questioner can
• 23:21
  remember that, and. Well, I think we all can.
• 23:23
  But can Professor Watson
• 23:26
  say, um, whether or not
• 23:29
  AI is being used by seti? Didn't
• 23:32
  we get that question the other day? Or
• 23:35
  a similar question about the use of AI in,
• 23:38
  um.
• 23:38
  In, uh, in astronomy? I don't know if we did
• 23:41
  it in regard to the search for
• 23:43
  extraterrestrials yeah.
• 23:45
  Professor Fred Watson: Yes, we did, we did. About the way it can be
• 23:48
  used to really tease out
• 23:50
  information that might otherwise,
• 23:53
  uh, go unnoticed because of the
• 23:56
  statistical methods that we use. So,
• 23:58
  um, uh, it's an
• 24:01
  intriguing thought though,
• 24:04
  uh, when you turn it the other way around in
• 24:06
  regard to seti, whether
• 24:09
  the putative extraterrestrial intelligence
• 24:12
  itself is using AI and may even be
• 24:15
  AI, um, how would we
• 24:17
  disentangle that from, um,
• 24:20
  a non AI, um,
• 24:22
  uh, extraterrestrial entity?
• 24:25
  It leads us into all kinds of uncharted
• 24:27
  waters. Does. That's quite an interesting
• 24:29
  question.
• 24:30
  Andrew Dunkley: It does indeed.
• 24:32
  Um, and back to
• 24:34
  Dave's, uh, tongue in cheek question.
• 24:38
  Uh, of course there is an
• 24:41
  object that they think is out there somewhere
• 24:44
  that we haven't yet found, and that's called
• 24:46
  Planet Nine. So
• 24:48
  even though I know, I know where he was
• 24:51
  coming from, he was, he was being extra
• 24:54
  funny and the comments are still coming from
• 24:56
  people who thought it was. Um, but in
• 24:59
  reality there, there is
• 25:01
  definitely a possibility of something out
• 25:04
  there that they haven't found, but they, they
• 25:06
  know it exists, whether
• 25:09
  it's a planet or a bunch of stuff,
• 25:13
  um, that's affecting
• 25:17
  the outer solar system, I suppose.
• 25:19
  Professor Fred Watson: Correct. And it's been in the news again
• 25:21
  recently. Actually. I almost, uh, put it up
• 25:23
  as one of the topics we should cover that,
• 25:26
  um, there have been more comments on
• 25:28
  the possibility of Planet Nine. The original
• 25:31
  researchers who highlighted this,
• 25:34
  um, Mike Brown and uh,
• 25:38
  one of his colleagues, they have
• 25:41
  basically said that
• 25:44
  if it's not Planet Nine, there is still
• 25:46
  something that needs explained, which is more
• 25:49
  or less what you've just said. Ah, but, um,
• 25:51
  they are still very confident that we will,
• 25:53
  uh, unearth a very distant planet, quite
• 25:56
  a massive one, that is affecting the orbits
• 25:59
  of these, um, trans neptunian objects,
• 26:02
  which are, ah, in very elongated orbits.
• 26:05
  So the jury's still out on it. It's one of
• 26:07
  these, I think it's one of these questions
• 26:08
  that we'll talk about for some time to come,
• 26:10
  Andrew.
• 26:12
  Andrew Dunkley: And like, the questions are coming, but we
• 26:14
  can't keep. We can't. Like, we'll be here all
• 26:17
  day if we go. But, um, back to the AI
• 26:20
  question.
• 26:20
  How else has AI been used in
• 26:22
  astronomy? Uh, I think the possibilities,
• 26:25
  uh, are endless, aren't they?
• 26:28
  Professor Fred Watson: Yeah, pretty. Well, um, uh, it's,
• 26:30
  it's, you know, I mean, people,
• 26:33
  the main ways, the way I've just described in
• 26:36
  terms of actually using it to advance
• 26:38
  astronomy, people use AI, I'm sure, for
• 26:41
  writing their papers. And I do know one of my
• 26:43
  colleagues in Arizona uses, uh, AI to
• 26:46
  mark the papers as well. Oh, uh, wow.
• 26:50
  Andrew Dunkley: Looking for patterns of people who didn't
• 26:53
  think for themselves.
• 26:55
  Professor Fred Watson: I think looking for the whole hug. Um, he
• 26:58
  presented a paper. This was at a conference.
• 27:00
  Was it last year or the year before? I think
• 27:01
  it was the year before last. Uh, which, um,
• 27:04
  he was very impressed with, um, the,
• 27:07
  uh, I don't know which breed of AI he was
• 27:10
  using, but he was very impressed with the
• 27:11
  outcomes from that and said they actually
• 27:14
  matched the human marking results,
• 27:17
  uh, very well. But just
• 27:20
  aside from that, I think, um, the main use
• 27:23
  in advancing astronomy is very much in
• 27:25
  applying it to these very large data sets.
• 27:28
  Andrew Dunkley: Yeah, I have used it quite a
• 27:31
  bit, uh, in researching elements of my
• 27:34
  books when I write. Um, I've already
• 27:37
  started a prequel to my latest to
• 27:40
  my new trilogy, which is,
• 27:43
  um, going well and thanks to everyone who's,
• 27:45
  who's bought a copy. Uh,
• 27:48
  and it's lots of fun. I actually, uh,
• 27:51
  have found a way of using AI,
• 27:53
  um, that I, uh, really
• 27:56
  enjoy. It's not just about doing a search,
• 27:58
  but you can sit there and literally have a
• 28:00
  conversation and, and weed out information as
• 28:03
  you go. It's, It's a lot of fun. Um,
• 28:06
  my wife thought I was, you know,
• 28:09
  a bit, um, beyond my station using AI
• 28:12
  because I'm, I'm not a young person. Um,
• 28:16
  she went to the hairdresser the other day
• 28:17
  and, um, the hairdresser said, I'm going to
• 28:19
  redesign my salon. I asked Chat GPT
• 28:22
  to design it for me. Well, now she's using
• 28:25
  AI, isn't she? Yeah. Okay. Wouldn't, wouldn't
• 28:27
  do it if I suggested a it. But
• 28:30
  the hairdresser, they know everything.
• 28:33
  Um, okay, thanks to everybody who's
• 28:36
  sending questions and, uh, our live audience
• 28:38
  for contributing as well. It's been a lot of
• 28:40
  fun and thank you, Fred Watson.
• 28:42
  Uh, that brings us to the end of yet another
• 28:44
  episode.
• 28:46
  Professor Fred Watson: It does, doesn't it? Yeah, well, I've learned
• 28:48
  something in that one. Um, that, uh, yes,
• 28:51
  angular momentum does, ah, add from
• 28:54
  accretive material. So there you go.
• 28:56
  Andrew Dunkley: All right, uh, we'll see you soon,
• 28:58
  Fred Watson. Thank you.
• 29:00
  Professor Fred Watson: Cheers.
• 29:00
  Andrew Dunkley: For now, Professor Fred Watson Watson,
• 29:02
  astronomer at large. And if you've got
• 29:04
  questions for us, please jump on our website,
• 29:06
  spacenutspodcast.com or spacenuts
• 29:09
  IO if you're a lazy typist. And
• 29:12
  click on the AMA tab at the top and send us
• 29:14
  your text or audio questions. Don't forget to
• 29:16
  tell us who you are and where you're from. We
• 29:18
  just like to know so that we can spam
• 29:21
  you later. Uh, and, uh, thanks to
• 29:24
  Huw in the studio. Um, although Huw couldn't
• 29:26
  be with us today. Uh, you know, we've
• 29:29
  been, um, searching for. For Planet nine,
• 29:31
  which is difficult to find, but I reckon
• 29:33
  we'll probably find it before we find Huw.
• 29:36
  And from me, Andrew Dunkley, thanks for your
• 29:38
  company. We'll see you on the next episode of
• 29:40
  Space Nuts. Bye.
• 29:42
  Professor Fred Watson: Bye.
• 29:43
  Andrew Dunkley: You've been listening to the Space Nuts
• 29:45
  podcast, available at
• 29:48
  Apple Podcasts, Spotify,
• 29:50
  iHeartRadio or your favourite podcast
• 29:53
  player. You can also stream on
• 29:55
  demand@bytes.com.
• 29:57
  Professor Fred Watson: this has been another quality podcast
• 29:59
  production from bytes.com.
• 30:01
  Berman Gorvine: um,