This episode is brought to you with the support of NordVPN - your first stop when it comes to online security and privacy. To check out our special money saving offer for Space Nuts liseners, visit www.nordvpn.com/spaenuts
In this Q&A edition of Space Nuts, host Andrew Dunkley and astronomer Professor Fred Watson tackle intriguing audience questions ranging from the possibility of stopping a photon to the complexities of intertwining electromagnetic fields. They also discuss the speeds of colliding particles in the Large Hadron Collider and the growing issue of excess satellites in space. Join us for a fascinating exploration of these cosmic queries!
Chapters:
(00:00) Space Nuts aims to answer audience questions in a Q and A edition(01:04) Professor Fred Watson answers an audio question from Andrew Chunk(02:03) Kevin asks question regarding whether we have stopped a photon from moving(10:30) Fred: The fabric of space time consists of different fields(14:30) Stay safe online with our sponsor, NordVPN Space Nuts(16:28) Question comes from Andy from Cheshire, UK(22:52) There is growing problem of excess satellites in space and what to do(30:10) Mark: Everything you said, um, is possible(30:38) If you have questions for Space Nuts, send them in
Become a supporter of this podcast: https://www.spreaker.com/podcast/space-nuts-astronomy-insights-cosmic-discoveries--2631155/support.
00:00:00 --> 00:00:01 Andrew Dunkley: Hi there.
00:00:01 --> 00:00:03 Andrew Dunkley: This is Space Nuts. It's a Q and A edition.
00:00:04 --> 00:00:06 Uh, my name is Andrew Dunkley. Thanks for
00:00:06 --> 00:00:08 your company. In, uh, this episode we will
00:00:08 --> 00:00:11 endeavour to answer audience
00:00:11 --> 00:00:14 questions. Uh, Kevin wants to know about
00:00:14 --> 00:00:16 stopping a photon. Did that really happen?
00:00:17 --> 00:00:19 Ah, we've got a, uh, duo
00:00:20 --> 00:00:22 named Reynold and Brian wanting to ask about
00:00:22 --> 00:00:25 intertwining electromagnetic fields.
00:00:26 --> 00:00:29 Um, the speed of colliding particles in the
00:00:29 --> 00:00:32 Large Hadron Collider is a question we've
00:00:32 --> 00:00:35 received. And Mark is asking us
00:00:35 --> 00:00:38 about the excess number of satellites in
00:00:38 --> 00:00:40 space and what can be done about it. He's got
00:00:40 --> 00:00:43 an idea. We will see what that's all about
00:00:43 --> 00:00:46 on this episode of space nuts.
00:00:46 --> 00:00:48 Generic: 15 seconds. Guidance is internal.
00:00:48 --> 00:00:51 10, 9. Ignition
00:00:51 --> 00:00:52 sequence start.
00:00:52 --> 00:00:53 Professor Fred Watson: Space nuts.
00:00:53 --> 00:00:56 Generic: 5, 4, 3. 2. 1. 2, 3, 4,
00:00:56 --> 00:00:58 5, 5, 4, 3, 2, 1.
00:00:58 --> 00:00:59 Professor Fred Watson: Space nuts.
00:00:59 --> 00:01:01 Generic: Astronauts report it feels good.
00:01:02 --> 00:01:04 Andrew Dunkley: And he's back again for more.
00:01:04 --> 00:01:06 Uh, it is Professor Fred Watson Watson,
00:01:06 --> 00:01:08 Astronomer at large. Hello Fred Watson.
00:01:08 --> 00:01:11 Professor Fred Watson: Hello Andrew. Um, fancy seeing you here. Yes,
00:01:12 --> 00:01:13 in my study.
00:01:13 --> 00:01:16 Andrew Dunkley: Yes, I'm in mine as well. Although it's
00:01:16 --> 00:01:18 hard to see because the background's all
00:01:18 --> 00:01:20 blurred. I must have a setting
00:01:21 --> 00:01:23 that I changed in this thing and I can't
00:01:23 --> 00:01:25 figure it out how to undo it. But um, it
00:01:25 --> 00:01:28 doesn't really matter. You probably don't
00:01:28 --> 00:01:29 want to see all the junk at the back of my
00:01:29 --> 00:01:32 room anyway. It's not as good as your
00:01:32 --> 00:01:32 junk.
00:01:32 --> 00:01:35 Professor Fred Watson: Oh, it's good Chunk. My microscope, uh, there
00:01:35 --> 00:01:35 as well.
00:01:35 --> 00:01:36 Andrew Dunkley: Oh yeah, that's nice.
00:01:37 --> 00:01:39 Professor Fred Watson: If I see anything I need to look at closely,
00:01:39 --> 00:01:41 I can just turn around in my chair and have a
00:01:41 --> 00:01:41 look.
00:01:41 --> 00:01:43 Andrew Dunkley: Yeah, well, your age, that's probably.
00:01:46 --> 00:01:47 You walked into that one.
00:01:47 --> 00:01:48 Professor Fred Watson: I did deny. Yes.
00:01:50 --> 00:01:52 Andrew Dunkley: Um, shall we answer some questions?
00:01:53 --> 00:01:54 Professor Fred Watson: Uh, no, no, let's
00:01:57 --> 00:01:59 Andrew Dunkley: uh, let's go to our first question. It's an
00:01:59 --> 00:02:01 audio question and it comes from Kevin.
00:02:03 --> 00:02:06 Kevin: Hello, space notes. My name is Kevin. I'm
00:02:06 --> 00:02:08 from Las Vegas, Nevada and I finally have a
00:02:08 --> 00:02:11 question to ask you after listening to you
00:02:11 --> 00:02:13 guys from the beginning. It's regarding
00:02:14 --> 00:02:16 an article that I came across but didn't get
00:02:16 --> 00:02:18 to fully read on how we have
00:02:18 --> 00:02:21 officially docked a particle
00:02:21 --> 00:02:24 of light. Not just slowed it down but full
00:02:24 --> 00:02:27 on. Um, stop. My question is kind of a
00:02:27 --> 00:02:30 two part A, is this a
00:02:30 --> 00:02:32 legitimate thing? Have we stopped a, uh,
00:02:32 --> 00:02:35 photon from moving and B,
00:02:36 --> 00:02:38 if not, this can be posed as a what if
00:02:38 --> 00:02:41 question. But what's the consequences for
00:02:41 --> 00:02:43 a photon that come to a complete stop?
00:02:43 --> 00:02:46 Now, photons don't have rest mass. It's only
00:02:46 --> 00:02:49 in the mass of their energy. But does
00:02:49 --> 00:02:52 it Gain rest mass now that it is at a rest
00:02:52 --> 00:02:55 or is this one of those it enters
00:02:56 --> 00:02:58 and just ends up going back to the speed of
00:02:58 --> 00:03:01 light once whatever's holding it lets go?
00:03:02 --> 00:03:04 Um, Google doesn't quite give me the run
00:03:04 --> 00:03:07 around for a bunch of stuff so I figured I'd
00:03:07 --> 00:03:10 ask you guys. Love the show. Thank you for
00:03:10 --> 00:03:11 listening.
00:03:11 --> 00:03:12 Professor Fred Watson: Thank you.
00:03:12 --> 00:03:14 Andrew Dunkley: Kevin. Uh, I love this question. Uh, this is
00:03:14 --> 00:03:17 a subject that has come up uh, a few times
00:03:17 --> 00:03:20 over the years and it prompted me to do
00:03:20 --> 00:03:23 a bit of research. Uh, and I did find uh,
00:03:23 --> 00:03:26 an article on the Physics World website
00:03:26 --> 00:03:27 that uh, discusses this.
00:03:27 --> 00:03:29 Professor Fred Watson: Fred Watson Good.
00:03:32 --> 00:03:34 Uh, yes, that's right. Look, it's ah,
00:03:36 --> 00:03:38 it really is an interesting um, process.
00:03:39 --> 00:03:42 Um, but it's uh, it's,
00:03:43 --> 00:03:46 there's a bit of subterfuge here in the
00:03:46 --> 00:03:46 nomenclature
00:03:47 --> 00:03:49 Andrew Dunkley: because well that's a big word.
00:03:50 --> 00:03:53 Professor Fred Watson: Uh, there is two big words
00:03:53 --> 00:03:55 there. Don't know what either of them mean.
00:03:57 --> 00:04:00 There's a, you're almost
00:04:00 --> 00:04:02 playing with words here in a way because
00:04:03 --> 00:04:06 you do stop light. But it's not
00:04:06 --> 00:04:08 the individual photon
00:04:09 --> 00:04:11 that stops. It gets
00:04:11 --> 00:04:13 converted into something else,
00:04:14 --> 00:04:16 if I can put it that way. So you've got to
00:04:16 --> 00:04:18 start off with a Bose
00:04:19 --> 00:04:21 Einstein condensate. A
00:04:21 --> 00:04:24 condensate which is ultra
00:04:24 --> 00:04:27 cold atoms, they're a fraction of a
00:04:27 --> 00:04:29 degree above absolute zero.
00:04:30 --> 00:04:33 And the thing about one of these, they're
00:04:33 --> 00:04:35 usually called a bec, a Bose Einstein
00:04:35 --> 00:04:38 condensate. Um, it is
00:04:38 --> 00:04:41 basically a whole lot of atoms and usually
00:04:41 --> 00:04:43 it's sodium, uh, which um,
00:04:44 --> 00:04:46 are so cold that they behave
00:04:47 --> 00:04:50 like a single quantum object. So
00:04:50 --> 00:04:52 it's a bit like entanglement
00:04:53 --> 00:04:55 where you've got two quantum particles and
00:04:55 --> 00:04:58 they um, behave like a single particle.
00:04:58 --> 00:05:01 It's that. But in a, in
00:05:01 --> 00:05:04 a whole petri dish if you like, a lot
00:05:04 --> 00:05:07 of um, a lot of uh, these atoms are
00:05:07 --> 00:05:09 entangled effectively. So you've got this
00:05:09 --> 00:05:12 bec, the boson condensate. But
00:05:12 --> 00:05:14 then you've got to uh,
00:05:14 --> 00:05:17 you sort of excite it with
00:05:17 --> 00:05:20 a laser and then you send your
00:05:20 --> 00:05:22 photon in that you want to stop.
00:05:23 --> 00:05:26 And um, it basically
00:05:26 --> 00:05:27 the photon,
00:05:30 --> 00:05:32 it's not a photon anymore. It's now
00:05:32 --> 00:05:35 interacting with these super cold
00:05:35 --> 00:05:38 atoms, uh, in a way that
00:05:39 --> 00:05:42 effectively slows the transfer of energy
00:05:42 --> 00:05:45 down. So it's not the same photon that
00:05:45 --> 00:05:48 stopped. It becomes something else. It
00:05:48 --> 00:05:50 becomes um, uh.
00:05:50 --> 00:05:53 One um, document I read
00:05:54 --> 00:05:56 suggests it's actually
00:05:56 --> 00:05:59 converted into a matter
00:05:59 --> 00:06:02 based hologram, uh, uh,
00:06:02 --> 00:06:05 which is a slightly um, odd way of putting it
00:06:05 --> 00:06:07 but basically it tells you that
00:06:08 --> 00:06:11 you've changed the photon but
00:06:11 --> 00:06:14 uh, you can then basically,
00:06:14 --> 00:06:17 um, there's
00:06:17 --> 00:06:20 a separate laser that's exciting the BEC
00:06:20 --> 00:06:23 into this unusual state. If you turn that
00:06:23 --> 00:06:26 off, uh, the pulse doesn't
00:06:26 --> 00:06:29 just slow down. Sorry, the
00:06:29 --> 00:06:31 photon that you're trying to stop actually
00:06:31 --> 00:06:34 does stop when you turn this energy off.
00:06:34 --> 00:06:36 And what you've got is
00:06:37 --> 00:06:38 essentially,
00:06:40 --> 00:06:41 Kevin: uh,
00:06:41 --> 00:06:42 Professor Fred Watson: all the information, if I can put it that
00:06:42 --> 00:06:45 way, contained in the photon is
00:06:45 --> 00:06:48 transferred into this imprint in
00:06:48 --> 00:06:50 the bec, in the atoms of the
00:06:51 --> 00:06:54 Bose Einstein condensate. It
00:06:54 --> 00:06:57 becomes, as I said earlier, like a hologram.
00:06:57 --> 00:06:59 But then if you turn that, what's called the
00:06:59 --> 00:07:02 coupling laser back on, um, the light
00:07:02 --> 00:07:05 pulse is reconstructed
00:07:05 --> 00:07:08 and sets off again on its path. I haven't
00:07:08 --> 00:07:11 explained that very well, but that's
00:07:11 --> 00:07:12 basically what's happening.
00:07:12 --> 00:07:14 Andrew Dunkley: Okay, so
00:07:15 --> 00:07:17 Kevin's right. Uh, we
00:07:17 --> 00:07:20 have demonstrated that you can
00:07:20 --> 00:07:23 slow light down. I, uh, think when the storey
00:07:23 --> 00:07:25 first came out, they actually said they
00:07:25 --> 00:07:27 stopped it. Uh, but
00:07:28 --> 00:07:30 second, uh, part of his question was,
00:07:31 --> 00:07:34 does it reconstitute itself and get on with
00:07:34 --> 00:07:36 its journey? And the answer is yes, that's
00:07:36 --> 00:07:36 correct.
00:07:36 --> 00:07:39 Professor Fred Watson: Yeah. So this is. It's not, um, a
00:07:39 --> 00:07:41 particular, you know, it's not a specific
00:07:41 --> 00:07:43 piece of research. This. There's a whole lot
00:07:43 --> 00:07:46 of research going on. It's almost like
00:07:46 --> 00:07:49 becoming, um, uh, just a
00:07:50 --> 00:07:53 everyday tool of physicists to do this, to
00:07:53 --> 00:07:56 stop pulses of light, uh, and
00:07:56 --> 00:07:58 tinker around and see what they can learn
00:07:58 --> 00:08:00 from it. Making that grossly
00:08:00 --> 00:08:03 oversimplified. So I apologise to all my
00:08:03 --> 00:08:06 physicist friends. Um, but it's, um,
00:08:06 --> 00:08:09 almost a routine process to do this. Now. I
00:08:09 --> 00:08:11 think I'm right in saying that not just.
00:08:12 --> 00:08:14 Although I suspect it's only a few labs in
00:08:14 --> 00:08:15 the world that have got the equipment
00:08:15 --> 00:08:17 necessary, uh, to do it. Because
00:08:18 --> 00:08:20 it's not just your everyday microscope or
00:08:20 --> 00:08:22 anything like that. It's, uh, quite a
00:08:22 --> 00:08:25 specific piece of, uh, infrastructure,
00:08:25 --> 00:08:27 including the Bose Einstein condensate, which
00:08:27 --> 00:08:30 I think we're all actually made in the. Was
00:08:30 --> 00:08:32 it in the 1980s? Um, they were predicted by
00:08:32 --> 00:08:35 Bose and Einstein, two physicists. Uh,
00:08:35 --> 00:08:38 but I don't think we actually managed to make
00:08:38 --> 00:08:40 one until maybe 40 years ago. I might have
00:08:40 --> 00:08:42 that date wrong, but that sticks in my mind.
00:08:43 --> 00:08:45 Andrew Dunkley: Yeah, that's fascinating. I wonder why we're
00:08:45 --> 00:08:48 so keen to learn how to do this with light. I
00:08:48 --> 00:08:51 mean, what do we gain from it?
00:08:51 --> 00:08:54 Professor Fred Watson: Well, um, uh, it
00:08:54 --> 00:08:57 teaches you about the properties of the Bose
00:08:57 --> 00:09:00 Einstein condensate. And
00:09:00 --> 00:09:02 being able to stop a photon and store its
00:09:02 --> 00:09:05 energy is quite an
00:09:05 --> 00:09:07 interesting thing. Particularly if
00:09:07 --> 00:09:10 you think, well, maybe we can apply this to
00:09:10 --> 00:09:13 quantum computing. I think that's
00:09:14 --> 00:09:16 uh, one of the reasons why this is a hot
00:09:16 --> 00:09:18 topic, uh, that it does have
00:09:19 --> 00:09:21 applications for quantum,
00:09:21 --> 00:09:24 uh, information. It also,
00:09:25 --> 00:09:28 um, you know, it relates to
00:09:28 --> 00:09:30 our understanding of physics at the most
00:09:30 --> 00:09:32 basic level. Uh, it's, uh.
00:09:32 --> 00:09:35 Yes, it's extraordinary. I think it is a very
00:09:35 --> 00:09:38 useful line of research and, um.
00:09:38 --> 00:09:41 Sounds like it, I think. Yes, I think I
00:09:41 --> 00:09:43 should understand it better. That's the
00:09:43 --> 00:09:43 bottom line.
00:09:44 --> 00:09:46 Andrew Dunkley: Kevin might also be interested to know the
00:09:46 --> 00:09:49 revival process after you switch the laser
00:09:49 --> 00:09:52 back on is quite slow. It's not like it
00:09:52 --> 00:09:54 instantly goes back to its 300 million
00:09:54 --> 00:09:57 metres per second. Um, light speed,
00:09:57 --> 00:10:00 uh, takes a little bit, and
00:10:00 --> 00:10:03 I'm talking a little bit of time to, to sort
00:10:03 --> 00:10:04 of rev its engines back up again.
00:10:05 --> 00:10:08 Professor Fred Watson: Yeah, so, so that's not. I mean, photons
00:10:08 --> 00:10:11 in a vacuum always travel at that 300
00:10:11 --> 00:10:13 or 300 kilometres per second, the way we
00:10:13 --> 00:10:16 usually put it, 300 million kilometres
00:10:16 --> 00:10:19 per second. Um, uh, but that's only
00:10:19 --> 00:10:21 the speed in a vacuum. The speed in
00:10:21 --> 00:10:24 different, um, other media is
00:10:24 --> 00:10:24 different.
00:10:26 --> 00:10:28 Andrew Dunkley: Thanks for the question, Kevin. That's um,
00:10:28 --> 00:10:29 that's a really interesting one.
00:10:30 --> 00:10:33 Our next question, Fred Watson, comes from.
00:10:33 --> 00:10:35 Uh, Now I'm going to assume this is two
00:10:35 --> 00:10:37 people. And the reason I say that is because
00:10:37 --> 00:10:39 the other day we read a note from Rennie in
00:10:39 --> 00:10:41 California about, uh, one of his grandsons
00:10:41 --> 00:10:44 being inspired to perhaps study astronomy in
00:10:44 --> 00:10:47 the future. And these two fellows
00:10:47 --> 00:10:49 sport the same surname as Rennie. So I'm
00:10:49 --> 00:10:52 going to assume these are two people,
00:10:52 --> 00:10:54 Reynold and who've sent this question in.
00:10:55 --> 00:10:58 And if I'm wrong, I'm sorry, but, uh, I just
00:10:58 --> 00:11:00 got that gut feeling about it. They haven't
00:11:00 --> 00:11:02 actually said these are from two different
00:11:02 --> 00:11:05 people, but, um, uh, the fabric
00:11:05 --> 00:11:07 of space time consists of different
00:11:07 --> 00:11:10 fields. An example is the Higgs field,
00:11:11 --> 00:11:14 uh, electromagnetic field, et cetera.
00:11:14 --> 00:11:16 So my question is, theoretically, could any
00:11:16 --> 00:11:19 of these fields intertwine and become
00:11:19 --> 00:11:21 a new type of field, or could the
00:11:21 --> 00:11:24 intertwining effect a, uh, field
00:11:24 --> 00:11:26 to interfere with its behaviour?
00:11:28 --> 00:11:29 That's getting really into the,
00:11:30 --> 00:11:33 um, big complexities of,
00:11:34 --> 00:11:35 uh, studying
00:11:38 --> 00:11:40 these particles.
00:11:41 --> 00:11:43 It's the smallest level of anything really,
00:11:43 --> 00:11:44 isn't it?
00:11:45 --> 00:11:47 Professor Fred Watson: That's correct, yes. So we're talking about
00:11:47 --> 00:11:49 fundamental particles which equally, uh,
00:11:50 --> 00:11:53 well, can be seen as, um, uh,
00:11:53 --> 00:11:55 as disturbances
00:11:56 --> 00:11:59 or eddies if you like, in, in the field, in
00:11:59 --> 00:12:01 the force field. Uh, so, you
00:12:01 --> 00:12:04 know, whatever that force field is. But I
00:12:04 --> 00:12:06 think there's a fairly straightforward answer
00:12:06 --> 00:12:09 to this question though. Uh, um.
00:12:09 --> 00:12:12 Exactly. As Reynolds and Brian say, the
00:12:12 --> 00:12:13 fabric of space time consists of different
00:12:13 --> 00:12:16 fields, such as the Higgs field. And the
00:12:16 --> 00:12:18 Higgs boson is a disturbance within the Higgs
00:12:18 --> 00:12:21 field. But, um,
00:12:21 --> 00:12:23 uh, and so the question is, theoretically,
00:12:23 --> 00:12:25 could any of these fields intertwine and
00:12:25 --> 00:12:28 become a new type of field or could the
00:12:28 --> 00:12:30 intertwining affect a field to interfere with
00:12:30 --> 00:12:33 its behaviour? And the answer is yes to the
00:12:33 --> 00:12:36 first part. They don't exactly
00:12:36 --> 00:12:38 intertwine, they superimpose. And
00:12:39 --> 00:12:41 you've actually, um, Reynold and Brian
00:12:41 --> 00:12:43 already named one because the
00:12:43 --> 00:12:46 electromagnetic field is actually a
00:12:46 --> 00:12:49 superposition of the electric field and the
00:12:49 --> 00:12:50 magnetic field, which are themselves
00:12:50 --> 00:12:52 separate. And there are other, there are
00:12:52 --> 00:12:55 other superpositions as well.
00:12:55 --> 00:12:58 Um, uh, the weak
00:12:58 --> 00:13:01 nuclear force intertwines with
00:13:01 --> 00:13:03 the electromagnetic force to become the
00:13:03 --> 00:13:05 electroweak force, which is something we
00:13:05 --> 00:13:08 think was present in the early universe.
00:13:09 --> 00:13:10 Uh, so, uh,
00:13:12 --> 00:13:15 yes, it's interesting the way that these
00:13:15 --> 00:13:17 superpositions happen. So they're absolutely
00:13:17 --> 00:13:20 right. They can entwine, uh, and, uh,
00:13:22 --> 00:13:24 um, at least maybe intertwines the wrong
00:13:24 --> 00:13:27 word. But, uh, superimpose at least so that
00:13:27 --> 00:13:29 you have multiple fields becoming
00:13:30 --> 00:13:32 something different, a new type of field.
00:13:32 --> 00:13:34 Exactly as they say. Okay, yeah.
00:13:34 --> 00:13:36 Andrew Dunkley: Ah, it's a strange world, isn't it, when you
00:13:36 --> 00:13:39 get down to the. It is
00:13:39 --> 00:13:42 tiny, tiny objects and, um,
00:13:42 --> 00:13:44 Professor Fred Watson: strange in the big objects as well.
00:13:45 --> 00:13:48 Andrew Dunkley: I suppose so. I mean, if you
00:13:48 --> 00:13:50 really sit back and drink a few scotches and
00:13:50 --> 00:13:53 start looking up and thinking about it, your
00:13:53 --> 00:13:55 brain just explodes. It's probably the scotch
00:13:55 --> 00:13:57 more so than the problems of the universe.
00:13:59 --> 00:14:01 Um, it is so
00:14:02 --> 00:14:04 out there when you're, you know, just
00:14:05 --> 00:14:08 contemplating existence itself is one
00:14:08 --> 00:14:10 of the things I find myself thinking about
00:14:10 --> 00:14:13 from time to time. How is existence
00:14:14 --> 00:14:16 not, not just why, but how.
00:14:18 --> 00:14:19 Uh, it's all very weird.
00:14:21 --> 00:14:22 Uh, and thank you to Reynold and Brian for
00:14:23 --> 00:14:25 sending in that question. And, um,
00:14:27 --> 00:14:29 we wish you well. Uh, and please send some
00:14:29 --> 00:14:29 more.
00:14:30 --> 00:14:32 Uh, this is Space Nuts, a Q and A edition
00:14:32 --> 00:14:34 with Andrew Dunkley and Professor Fred Watson
00:14:34 --> 00:14:35 Watson.
00:14:36 --> 00:14:38 Andrew Dunkley: Let's take a short break from the show to
00:14:38 --> 00:14:41 tell you about our sponsor, NordVPN.
00:14:41 --> 00:14:43 Uh, let's talk about your online security.
00:14:44 --> 00:14:47 Now, I can tell you from personal experience,
00:14:47 --> 00:14:50 uh, last year when Judy and I were overseas,
00:14:50 --> 00:14:52 we ran into, uh, a bit of a frustrating
00:14:52 --> 00:14:55 issue. There were certain apps we simply
00:14:55 --> 00:14:58 couldn't use without a VPN connection. Things
00:14:58 --> 00:15:01 like our, um, banking apps, uh, they wouldn't
00:15:01 --> 00:15:03 load. Uh, and even a sports app I rely
00:15:03 --> 00:15:06 on wouldn't, uh, let me watch games back home
00:15:06 --> 00:15:08 because of, of geo fencing and things like
00:15:08 --> 00:15:11 that. Uh, so, um, with NordVPN,
00:15:11 --> 00:15:14 I was able to watch, uh, football back
00:15:14 --> 00:15:17 home while crossing the Atlantic Ocean.
00:15:17 --> 00:15:19 Andrew Dunkley: It was pretty weird, but, uh, it worked.
00:15:20 --> 00:15:23 Andrew Dunkley: Uh, and uh, NORDVPN is the best in the
00:15:23 --> 00:15:25 business. Uh, with NordVPN, you can securely
00:15:25 --> 00:15:27 connect to servers all around the world,
00:15:27 --> 00:15:30 which means your apps think you right back
00:15:30 --> 00:15:33 home even when you're not. Uh, uh. It also
00:15:33 --> 00:15:35 encrypts your Internet traffic, hides your IP
00:15:35 --> 00:15:37 address and keeps your personal data safe
00:15:37 --> 00:15:40 from hackers and trackers and anybody else
00:15:40 --> 00:15:42 who's trying to get at you online.
00:15:43 --> 00:15:46 And this can happen in, um, public WI fi
00:15:46 --> 00:15:48 situations, in hotels, airports, cafes,
00:15:48 --> 00:15:51 anywhere like that. The best part, it's
00:15:51 --> 00:15:54 fast. Thousands of servers globally and their
00:15:54 --> 00:15:57 Nordlynx technology allows, uh, you to
00:15:57 --> 00:16:00 run seamlessly, no slowing down. It
00:16:00 --> 00:16:02 is brilliant. Right now you can grab the
00:16:02 --> 00:16:05 special Space Nuts deal through this URL
00:16:05 --> 00:16:07 nordvpn.com
00:16:07 --> 00:16:10 spacenuts you'll get four extra months free,
00:16:10 --> 00:16:13 plus a 30 day money back guarantee. So
00:16:13 --> 00:16:15 there's absolutely no risk if you
00:16:15 --> 00:16:16 Andrew Dunkley: want to give it a go.
00:16:16 --> 00:16:18 Andrew Dunkley: That's nordvpn.com
00:16:18 --> 00:16:21 spacenuts Stay safe
00:16:21 --> 00:16:23 online with our sponsor,
00:16:23 --> 00:16:24 NordVPN
00:16:27 --> 00:16:28 Kevin: Space Nuts.
00:16:28 --> 00:16:30 Andrew Dunkley: Uh, I think we've got another audio question.
00:16:30 --> 00:16:33 We seem to be on a bit of a, um, um,
00:16:33 --> 00:16:36 um, you know, particle
00:16:36 --> 00:16:39 type of bender at the moment with this
00:16:39 --> 00:16:41 episode. Uh, this, this question comes from
00:16:41 --> 00:16:42 Andy.
00:16:43 --> 00:16:45 Andy: Hi guys. Andy again, from uk,
00:16:45 --> 00:16:47 actually from Cheshire, just down the road
00:16:47 --> 00:16:50 from the beautiful Jodrell Bank. Although
00:16:50 --> 00:16:52 I've never forgiven them since they took out
00:16:52 --> 00:16:55 the planetarium. Um, just a quick question.
00:16:55 --> 00:16:58 Um, the lhc, um,
00:16:58 --> 00:17:00 we're told that it
00:17:01 --> 00:17:03 accelerates particles to
00:17:04 --> 00:17:06 very close to the speed of light, about 0.9 C
00:17:06 --> 00:17:09 or whatever the actual figure is.
00:17:09 --> 00:17:12 Um, but they also say that
00:17:12 --> 00:17:14 they're colliding particles at close to the
00:17:14 --> 00:17:17 speed of light. Now if they're colliding
00:17:17 --> 00:17:18 particles that they're accelerating in
00:17:18 --> 00:17:21 opposite directions, surely that means they
00:17:21 --> 00:17:24 should be the collisions. The impact
00:17:24 --> 00:17:27 should be at close to twice
00:17:27 --> 00:17:29 the speed of light. Um,
00:17:30 --> 00:17:32 if you just clear that one up, I'd be very
00:17:32 --> 00:17:34 happy. Um, I,
00:17:36 --> 00:17:38 I think I'm right and I think the collisions
00:17:38 --> 00:17:39 are happening at greater than the speed of
00:17:39 --> 00:17:42 light. But prove me wrong
00:17:42 --> 00:17:45 again, fantastic show. Speak to you soon.
00:17:46 --> 00:17:49 Andrew Dunkley: Thanks, Andy. Um, reminds me of all
00:17:49 --> 00:17:49 those,
00:17:52 --> 00:17:52 Andrew Dunkley: I
00:17:52 --> 00:17:53 Andrew Dunkley: suppose, when they're teaching you to drive
00:17:53 --> 00:17:56 and they're saying, um, look, you're
00:17:56 --> 00:17:58 driving along the highway at 100 kilometres
00:17:58 --> 00:18:00 an hour and a car's coming in the opposite
00:18:00 --> 00:18:02 direction at 100 kilometres an hour and you,
00:18:03 --> 00:18:06 uh, sadly, hit each other. The
00:18:06 --> 00:18:08 impact speed is 200 kilometres an hour. I
00:18:08 --> 00:18:09 guess that's what he's getting at.
00:18:10 --> 00:18:12 Professor Fred Watson: Exactly that, yes. Um,
00:18:13 --> 00:18:16 um, and it's a natural thing and it's a
00:18:16 --> 00:18:19 question that we often get, uh, because it's
00:18:19 --> 00:18:20 completely counterintuitive.
00:18:22 --> 00:18:25 Uh, exactly as, um, as Andy's saying. Uh,
00:18:25 --> 00:18:28 and yeah, Cheshire's lovely. He's right. And
00:18:28 --> 00:18:31 so is Jodrell Bank. Um, uh, uh,
00:18:31 --> 00:18:33 as Andy's saying, you're colliding these
00:18:33 --> 00:18:36 things. If I remember rightly, the, uh,
00:18:36 --> 00:18:38 proton, uh, speed
00:18:39 --> 00:18:41 within the Large Hadron Collider,
00:18:42 --> 00:18:42 I think it's
00:18:42 --> 00:18:46 9998%
00:18:46 --> 00:18:49 of the speed of light. So that's how fast
00:18:49 --> 00:18:51 these things are going, almost the speed of
00:18:51 --> 00:18:54 light. And you've got two, uh, streams of
00:18:54 --> 00:18:56 them going in opposite directions. You bring
00:18:56 --> 00:18:58 them together at the various experiment
00:18:58 --> 00:19:01 points. Um, I've been to some of those. I've
00:19:01 --> 00:19:03 been in the cavity at the cavern, actually,
00:19:03 --> 00:19:05 where the compact muon solenoid lives.
00:19:06 --> 00:19:08 Uh, and that's where they collide. So
00:19:08 --> 00:19:10 shouldn't they collide at nearly twice the
00:19:10 --> 00:19:12 speed of light? And the answer is no,
00:19:13 --> 00:19:13 because then
00:19:13 --> 00:19:14 Andrew Dunkley: you ought to be no.
00:19:14 --> 00:19:17 Professor Fred Watson: Yeah, that only works in classical mechanics,
00:19:18 --> 00:19:20 uh, where, as you said, the velocities just
00:19:20 --> 00:19:23 add together. Uh, if these things were
00:19:23 --> 00:19:26 moving, you know, in the, what we call the
00:19:26 --> 00:19:29 classical realm, in other words, slow stuff,
00:19:29 --> 00:19:31 you would add the velocities together. Uh,
00:19:31 --> 00:19:33 but when you get to
00:19:33 --> 00:19:36 relativistic speeds, as we call them, speeds
00:19:36 --> 00:19:39 close to the speed of light, you have to
00:19:39 --> 00:19:42 account for two other relativistic
00:19:42 --> 00:19:44 factors, which are, uh, time dilation
00:19:44 --> 00:19:47 and length contraction. And both of those
00:19:47 --> 00:19:50 things are things, uh, that become very
00:19:50 --> 00:19:52 significant at, uh, nearly the speed of
00:19:52 --> 00:19:54 light. And so when you take those into
00:19:54 --> 00:19:57 account, you get a different formula. And
00:19:58 --> 00:19:59 I don't know whether listeners are going to
00:19:59 --> 00:20:02 turn off here, but, uh, I'm going to give you
00:20:02 --> 00:20:04 the formula. So in the
00:20:04 --> 00:20:07 classical case, if you've got two
00:20:07 --> 00:20:10 velocities, U and V, it's always U and V,
00:20:10 --> 00:20:12 not you and me, U and V. Um,
00:20:13 --> 00:20:16 uh, and yes, in classical case, U plus
00:20:16 --> 00:20:18 V is
00:20:18 --> 00:20:21 the closing speed, but in the relativistic
00:20:21 --> 00:20:24 case, the Closing speed is u
00:20:24 --> 00:20:26 +v divided by
00:20:27 --> 00:20:28 1 over u
00:20:29 --> 00:20:32 times v over c squared.
00:20:33 --> 00:20:36 So u +v divided by 1 over
00:20:36 --> 00:20:38 UV over c squared. That's the
00:20:38 --> 00:20:41 relativistic formula. And when you put the
00:20:41 --> 00:20:44 numbers in, uh, you realise
00:20:44 --> 00:20:47 that you can never, uh, exceed the speed
00:20:47 --> 00:20:48 of light by this.
00:20:50 --> 00:20:53 Um, you just get, uh, an answer
00:20:53 --> 00:20:55 that's even closer to the speed of light than
00:20:55 --> 00:20:58 your two initial, uh, colliders.
00:20:58 --> 00:21:01 So, um, here's an example. Uh,
00:21:01 --> 00:21:03 you've got two things travelling,
00:21:04 --> 00:21:07 hitting each other or travelling towards each
00:21:07 --> 00:21:09 other at 0.8 of the speed of light.
00:21:09 --> 00:21:12 In the classical situation, they would be
00:21:13 --> 00:21:15 coming together at 1.6 times the speed of
00:21:15 --> 00:21:17 light. That will be their relative veloc. But
00:21:17 --> 00:21:20 when you do the relativistic calculation, uh,
00:21:20 --> 00:21:22 their Closing velocity is
00:21:22 --> 00:21:25 0 times the
00:21:25 --> 00:21:26 speed of light.
00:21:26 --> 00:21:26 Andrea: Okay.
00:21:31 --> 00:21:31 Andrew Dunkley: Okay.
00:21:33 --> 00:21:36 Professor Fred Watson: I hope that makes sense. It's all
00:21:36 --> 00:21:38 about the weird things that happen when you
00:21:38 --> 00:21:40 get near the speed of light. You know, time
00:21:40 --> 00:21:42 dilation itself, time slowing down for,
00:21:43 --> 00:21:45 uh, you know, for the. For as
00:21:45 --> 00:21:47 a difference between the observer and the
00:21:47 --> 00:21:49 person moving at the speed of light and
00:21:49 --> 00:21:50 length contraction. These are all weird
00:21:50 --> 00:21:53 things. So it shouldn't be a surprise that
00:21:53 --> 00:21:55 they don't just. The velocities don't just
00:21:55 --> 00:21:56 add together, they combine in that
00:21:56 --> 00:21:59 relativistic sense. Sorry about the equation.
00:21:59 --> 00:22:01 It's an equation I quite like, which is why I
00:22:01 --> 00:22:02 threw it in there.
00:22:04 --> 00:22:06 Andrew Dunkley: It's fair enough, too. And, uh, hopefully
00:22:06 --> 00:22:09 that's solved, uh, Andy's dilemma.
00:22:09 --> 00:22:12 Um, he thought it would be twice the
00:22:12 --> 00:22:13 speed of light or something to that effect if
00:22:13 --> 00:22:16 you got two objects at the speed of light
00:22:16 --> 00:22:19 impacting each other head on. But no, can't
00:22:19 --> 00:22:21 be done is what you're saying.
00:22:22 --> 00:22:25 Professor Fred Watson: Yeah, they're close. I mean, only light
00:22:25 --> 00:22:26 can go at the speed of light. So you're
00:22:26 --> 00:22:28 talking about things going at nearly the
00:22:28 --> 00:22:31 speed of light. Uh, they're not colliding at
00:22:31 --> 00:22:32 nearly twice the speed of light. They're
00:22:32 --> 00:22:35 colliding at even more nearly the speed of
00:22:35 --> 00:22:37 light than they were to start with. But it
00:22:37 --> 00:22:39 never exceeds the speed of light.
00:22:39 --> 00:22:42 Andrew Dunkley: I get it. There you go, Andy. Uh, solved.
00:22:45 --> 00:22:47 Professor Fred Watson: The crew of Artemis 2 now bound for the moon.
00:22:48 --> 00:22:50 Humanity's next great voyage begins.
00:22:51 --> 00:22:52 Andrew Dunkley: Space Nuts.
00:22:52 --> 00:22:55 Andrew Dunkley: And our final question today comes, uh,
00:22:55 --> 00:22:58 from. Mark. Hi, Fred Watson, Andrew, uh,
00:22:58 --> 00:23:01 and team. It's, uh, Mark again from Sunny,
00:23:01 --> 00:23:02 is it Cece.
00:23:04 --> 00:23:06 Professor Fred Watson: Yes, it's where Patrick Moore used to live.
00:23:07 --> 00:23:08 He used to visit him.
00:23:08 --> 00:23:11 Andrew Dunkley: I really have to use a bigger font size with
00:23:11 --> 00:23:14 these questions. Sunny, uh, Selsey on the
00:23:14 --> 00:23:17 south coast of England. Um, in more
00:23:17 --> 00:23:19 than one of your podcasts, you mentioned the
00:23:19 --> 00:23:22 growing problem of excess satellites in space
00:23:22 --> 00:23:24 and what to do with them. That got me
00:23:24 --> 00:23:26 thinking. Would it be possible to use the
00:23:26 --> 00:23:29 action reaction principle to place a new
00:23:29 --> 00:23:31 satellite in the same place as an old
00:23:31 --> 00:23:34 one and move the old one into a higher
00:23:34 --> 00:23:37 graveyard orbit? Uh, Then at a later date,
00:23:37 --> 00:23:40 collect them to be dismantled safely. The way
00:23:40 --> 00:23:42 I look at it, if they want to put more
00:23:42 --> 00:23:44 satellites into space, they should also pay
00:23:44 --> 00:23:47 to clean the space up. Uh, I know this
00:23:47 --> 00:23:50 sounds, uh, a, uh, bit space
00:23:50 --> 00:23:53 snook, a bit like space space snooker. Yes,
00:23:53 --> 00:23:55 it does. Uh, but would it be possible. By the
00:23:55 --> 00:23:58 way, I broke the TV in the Globe Pub as a
00:23:58 --> 00:24:01 young man playing snooker, so probably not a
00:24:01 --> 00:24:03 good idea to ask me to work out the
00:24:03 --> 00:24:05 trajectories for all of this. Keep, uh, up
00:24:05 --> 00:24:07 the great work. It means a lot to everyone
00:24:07 --> 00:24:09 listening. And those, uh, that don't, well,
00:24:09 --> 00:24:11 you just gotta pity them,
00:24:12 --> 00:24:14 says Mark. Thanks, Mark, for the question.
00:24:15 --> 00:24:17 Uh, I'd love to, I'd love to have been the
00:24:17 --> 00:24:18 night he broke the tv.
00:24:18 --> 00:24:20 Professor Fred Watson: That would have been spectacular.
00:24:20 --> 00:24:20 Generic: Yeah.
00:24:20 --> 00:24:21 Andy: Gosh.
00:24:22 --> 00:24:24 Andrew Dunkley: Now what I want to know is, was that he's
00:24:24 --> 00:24:27 backswing, getting ready for the, the,
00:24:27 --> 00:24:29 the move of the queue that hit the screen, or
00:24:29 --> 00:24:31 did he actually fire a ball,
00:24:32 --> 00:24:35 uh, across the, across the room and hit the
00:24:35 --> 00:24:38 tv? Uh, you're gonna have to clarify that
00:24:38 --> 00:24:40 one, Mark. Um, look,
00:24:41 --> 00:24:42 uh, in, in regard to, um,
00:24:43 --> 00:24:45 cleaning up your own mess, there's actually
00:24:45 --> 00:24:48 a. Isn't there an international law
00:24:48 --> 00:24:51 that requires you to deal with your own
00:24:51 --> 00:24:52 stuff up there?
00:24:52 --> 00:24:55 Professor Fred Watson: Yes, there is now. Um, I think it was added
00:24:55 --> 00:24:57 to the, uh, the
00:24:57 --> 00:24:59 approvals given by the International
00:24:59 --> 00:25:01 Telecommunications Union, which is a
00:25:01 --> 00:25:04 governing body of all this stuff, um,
00:25:04 --> 00:25:06 that you. I think this came in
00:25:06 --> 00:25:09 probably five, 10 years ago. You have to
00:25:09 --> 00:25:12 demonstrate, uh, before they'll give you
00:25:12 --> 00:25:15 permission to launch, that you've got a way
00:25:15 --> 00:25:17 of removing your spacecraft from
00:25:17 --> 00:25:20 orbit. Um, in other words,
00:25:20 --> 00:25:22 you've got to be able to clean up your own
00:25:22 --> 00:25:24 junk. Uh, now that's
00:25:25 --> 00:25:27 fine for new stuff, but there's a lot of
00:25:27 --> 00:25:30 stuff up there that didn't
00:25:30 --> 00:25:32 qualify for that. And no thought was given to
00:25:32 --> 00:25:35 the idea of trashing space that you, you
00:25:35 --> 00:25:38 know, your spacecraft would
00:25:38 --> 00:25:41 just continue in orbit, um, after
00:25:41 --> 00:25:44 its useful life was over. And
00:25:44 --> 00:25:46 indeed for many of them, for objects,
00:25:47 --> 00:25:50 uh, especially ones with solar panels which
00:25:50 --> 00:25:52 are big and act as a drag on the residual
00:25:52 --> 00:25:55 atmosphere up there. Uh, even if you're up
00:25:55 --> 00:25:57 at, uh, uh, four or five hundred
00:25:57 --> 00:26:00 kilometres, there's enough atmosphere that
00:26:00 --> 00:26:03 if you do nothing, your spacecraft will,
00:26:03 --> 00:26:06 uh, the orbit will decay. It will
00:26:06 --> 00:26:08 hit the atmosphere and slow down and that
00:26:08 --> 00:26:11 brings it down lower and then it slows down
00:26:11 --> 00:26:14 more. And that is how
00:26:15 --> 00:26:18 space is kind of almost automatically cleaned
00:26:18 --> 00:26:18 up.
00:26:19 --> 00:26:21 Andrew Dunkley: And that's what's happening to the Swift.
00:26:21 --> 00:26:23 Professor Fred Watson: Uh, yes, that we talked about a couple of
00:26:23 --> 00:26:25 episodes ago. Exactly right. That's right.
00:26:25 --> 00:26:28 And that one's worth saving, which is why a
00:26:28 --> 00:26:30 mission's been mounted to do that, to boost
00:26:30 --> 00:26:32 it into a higher orbit. So in a way, what
00:26:32 --> 00:26:34 that's doing is actually what Mark is
00:26:34 --> 00:26:37 suggesting. You, uh, can go, uh,
00:26:37 --> 00:26:38 attach another rocket to it and push it up to
00:26:38 --> 00:26:41 a higher orbit to safeguard it. Um,
00:26:42 --> 00:26:45 um, so for low Earth
00:26:45 --> 00:26:48 orbit, There's below about 5,
00:26:48 --> 00:26:50 600 kilometres. There is this natural
00:26:50 --> 00:26:53 sweeping up as things decay
00:26:53 --> 00:26:55 unless you do something about it. Many
00:26:55 --> 00:26:58 spacecraft have got thrusters that lets you
00:26:58 --> 00:27:01 lift its orbit. Um, but if you switch the
00:27:01 --> 00:27:03 thrusters off, that means they're going to
00:27:03 --> 00:27:04 come back to Earth anyway. And that might be
00:27:04 --> 00:27:06 enough to satisfy the international
00:27:06 --> 00:27:09 Telecommunications Unit, uh, going higher
00:27:09 --> 00:27:10 up, though.
00:27:10 --> 00:27:11 Andrew Dunkley: Except.
00:27:11 --> 00:27:13 Andrew Dunkley: Yes, one more point. Uh, when these things
00:27:13 --> 00:27:15 are burning up, they're putting all those
00:27:15 --> 00:27:17 metals into our atmosphere.
00:27:17 --> 00:27:19 Professor Fred Watson: Yeah, you're still getting contamination.
00:27:19 --> 00:27:21 That's right. We're getting aluminium oxide
00:27:21 --> 00:27:23 and all sorts of stuff up there that
00:27:23 --> 00:27:25 shouldn't be there. Uh, but,
00:27:25 --> 00:27:27 um, yes, for higher orbits,
00:27:30 --> 00:27:32 these are the ones, what you might call mid
00:27:32 --> 00:27:34 earth orbits above 1 kilometres,
00:27:35 --> 00:27:38 uh, they're not gonna decay so readily. And
00:27:38 --> 00:27:40 so they are an. And then,
00:27:41 --> 00:27:44 uh, the, um, geostationary
00:27:45 --> 00:27:47 satellites. So the geostationary orbits are
00:27:47 --> 00:27:50 very, very specific. Um, in fact,
00:27:50 --> 00:27:52 all the satellites are in the same orbit,
00:27:52 --> 00:27:54 more or less, um, because it's the one that
00:27:55 --> 00:27:57 keeps them over the equator and keeps them
00:27:57 --> 00:28:00 going, uh, round once in a day.
00:28:00 --> 00:28:03 Um, those geostationary orbits, they're at
00:28:03 --> 00:28:05 36 kilometres. They have to have
00:28:05 --> 00:28:08 mechanisms to push them into what's called
00:28:08 --> 00:28:11 exactly as, uh, Malik mentions, a grave
00:28:12 --> 00:28:15 orbit, which just gets them out of the way so
00:28:15 --> 00:28:16 that when they become defunct and you can't
00:28:16 --> 00:28:18 control them anymore, they're not going to
00:28:18 --> 00:28:20 bang into one of the active geostationary
00:28:20 --> 00:28:23 satellites. So it is a game of snooker up
00:28:23 --> 00:28:26 there, um, in a perhaps more gentle way than
00:28:26 --> 00:28:29 knocking one satellite into another, um, and
00:28:29 --> 00:28:31 replacing its position in space.
00:28:32 --> 00:28:34 All you do, if you do that is
00:28:35 --> 00:28:37 you've got another one that's going to decay
00:28:37 --> 00:28:38 at the same rate. If it's in low Earth orbit,
00:28:38 --> 00:28:39 it.
00:28:39 --> 00:28:41 Andrew Dunkley: Yeah, they reckon there's somewhere between
00:28:41 --> 00:28:44 three and four and a half thousand inactive
00:28:44 --> 00:28:46 or defunct satellites in orbit at the moment.
00:28:47 --> 00:28:49 Professor Fred Watson: That's correct, yes. Um, but
00:28:49 --> 00:28:52 then on top of that there's a, uh, host
00:28:52 --> 00:28:55 of, uh, upper stages, launch,
00:28:55 --> 00:28:58 you know, the launch vehicles. Lots of bits
00:28:58 --> 00:29:00 and pieces, bits of fairing, bits of junk,
00:29:00 --> 00:29:03 debris from previous collisions. It's a
00:29:03 --> 00:29:05 fleck of paint, flecks of Paint. That's
00:29:05 --> 00:29:06 right. There's even a glove.
00:29:08 --> 00:29:10 Andrew Dunkley: And a spanner with a spanner too. Yeah,
00:29:10 --> 00:29:13 there's all sorts of stuff floating around.
00:29:13 --> 00:29:15 Professor Fred Watson: It's all going at 8 kilometres per second.
00:29:15 --> 00:29:17 That's the dangerous bit.
00:29:17 --> 00:29:20 Andrew Dunkley: So I think that, uh, was another part to his
00:29:20 --> 00:29:23 question. Could you replace a satellite in
00:29:23 --> 00:29:26 its exact position, move the
00:29:26 --> 00:29:28 defunct one out and put a new one in the
00:29:28 --> 00:29:31 exact spot that its predecessor was?
00:29:31 --> 00:29:33 Professor Fred Watson: Well, you could, and, uh, indeed that's done.
00:29:33 --> 00:29:36 You don't move the other one out. You. Once
00:29:36 --> 00:29:38 its orbit's decayed, you, uh, just let it
00:29:38 --> 00:29:41 drop. Yeah, you've got that orbit, uh, freed
00:29:41 --> 00:29:43 up and you put another
00:29:43 --> 00:29:44 spacecraft there. That's what's happening
00:29:44 --> 00:29:46 with Starlink. Actually, it's exactly what's
00:29:46 --> 00:29:49 happening. The Starlink satellites are all at
00:29:49 --> 00:29:51 round about 500 kilometres. They were
00:29:51 --> 00:29:54 planning another shell at, uh, 1200
00:29:54 --> 00:29:57 kilometres. But, uh, for once, um, SpaceX
00:29:57 --> 00:29:59 listened to the astronomy lobby. Because
00:29:59 --> 00:30:01 those outer ones can be visible all night in
00:30:01 --> 00:30:04 some parts of the world, um, even though
00:30:04 --> 00:30:06 they're fainter because they're higher up,
00:30:06 --> 00:30:08 uh, it means that they're visible for much
00:30:08 --> 00:30:10 longer during twilight.
00:30:10 --> 00:30:13 Andrew Dunkley: Yeah, and that's a real problem, isn't
00:30:13 --> 00:30:16 it? There you go, Mark. Uh, everything you
00:30:16 --> 00:30:19 said, um, is possible. And
00:30:19 --> 00:30:22 uh, yes, there is a law requiring people to
00:30:22 --> 00:30:24 clean up their messes, but at the moment,
00:30:24 --> 00:30:26 letting them burn up in the atmosphere is
00:30:26 --> 00:30:29 okay until we all die of some
00:30:29 --> 00:30:32 kind of metallic poisoning. Then, um, they'll
00:30:32 --> 00:30:33 go, ah, yeah, we should have done, done
00:30:33 --> 00:30:34 something about that.
00:30:35 --> 00:30:37 Professor Fred Watson: Unintended consequences. Yeah.
00:30:37 --> 00:30:38 Andrew Dunkley: Uh, lovely to hear from you, Mark.
00:30:38 --> 00:30:41 Um, uh, we've been talking a lot
00:30:41 --> 00:30:44 about particle science today, and, uh, Andrea
00:30:44 --> 00:30:47 in Western Australia sent, uh, something in
00:30:47 --> 00:30:49 a while back and I've kind of been sitting on
00:30:49 --> 00:30:51 it, trying to find the appropriate moment.
00:30:51 --> 00:30:53 And because of the, the fact that three of
00:30:53 --> 00:30:56 our four questions were focused on, on
00:30:56 --> 00:30:59 particles, I thought it was appropriate
00:30:59 --> 00:31:00 to play, um, uh,
00:31:01 --> 00:31:03 Andrea's little voice piece today.
00:31:05 --> 00:31:08 Andrea: Hey, you two. The joke for the day.
00:31:09 --> 00:31:12 Two neutrinos walked through a bar.
00:31:14 --> 00:31:15 Andrew Dunkley: Thanks folks.
00:31:15 --> 00:31:17 Andrea: Really enjoy your show and I hope you guys
00:31:17 --> 00:31:18 found that really fun.
00:31:18 --> 00:31:19 Professor Fred Watson: We did.
00:31:21 --> 00:31:22 Andrew Dunkley: Uh, that's a good one.
00:31:22 --> 00:31:24 Professor Fred Watson: That is excellent. Yeah, perfect.
00:31:24 --> 00:31:27 Andrew Dunkley: Perfect timing. Well, actually, I've been
00:31:27 --> 00:31:30 sitting on it for months, but it,
00:31:30 --> 00:31:32 um, seemed appropriate. Appropriate today.
00:31:32 --> 00:31:33 Professor Fred Watson: Yes, that's the, um, one.
00:31:34 --> 00:31:36 Andrew Dunkley: Now a reminder, if you have questions for us,
00:31:36 --> 00:31:39 we would love to get them. Uh, you need to go
00:31:39 --> 00:31:41 to our website to send them in, uh, which is
00:31:41 --> 00:31:44 easy, spacenutspodcast.com or spacenuts
00:31:44 --> 00:31:46 IO. Click on the Ask me anything button at
00:31:46 --> 00:31:48 the top, it's labelled ama.
00:31:49 --> 00:31:51 And that's also the logo for the Australian
00:31:51 --> 00:31:53 Medical Association. But don't get confused.
00:31:54 --> 00:31:56 Uh, they might answer it too, though. You
00:31:56 --> 00:31:58 never know. Uh, but send your questions into
00:31:58 --> 00:32:01 us because, um, there's so much stuff that
00:32:01 --> 00:32:02 people want to know and if you want to know
00:32:02 --> 00:32:05 something, the best way to find out is to ask
00:32:05 --> 00:32:07 us and then we'll refer it to somebody else.
00:32:07 --> 00:32:10 But, uh, it is, um, uh, text and audio.
00:32:10 --> 00:32:13 Don't forget to tell us who you are and where
00:32:13 --> 00:32:15 you're from. Thank you so much, Fred Watson.
00:32:15 --> 00:32:16 It's been a pleasure.
00:32:16 --> 00:32:18 Professor Fred Watson: Always a pleasure, Andrew. Great to talk.
00:32:19 --> 00:32:20 Andrew Dunkley: Catch you soon. Professor Fred Watson Watson,
00:32:20 --> 00:32:23 astronomer at large. And, uh, thanks to Huw
00:32:23 --> 00:32:25 in the studio, who puts everything together
00:32:25 --> 00:32:27 with Blu Tack. Couldn't be with us today
00:32:27 --> 00:32:30 though, because he drives a proton and it
00:32:30 --> 00:32:33 does not do the speed of light. And so he was
00:32:33 --> 00:32:35 late. And from me, Andrew Dunkley. Thanks for
00:32:35 --> 00:32:37 your company. We'll catch you on the next
00:32:37 --> 00:32:38 episode of Space Nuts.
00:32:38 --> 00:32:39 Professor Fred Watson: Bye. Bye.
00:32:40 --> 00:32:42 Andrew Dunkley: You've been listening to the Space Nuts
00:32:42 --> 00:32:45 podcast, available at
00:32:45 --> 00:32:47 Apple Podcasts, Spotify,
00:32:48 --> 00:32:50 iHeartRadio or your favourite podcast
00:32:50 --> 00:32:52 player. You can also stream on
00:32:52 --> 00:32:54 demand@bytes.com.
00:32:54 --> 00:32:56 Andrew Dunkley: this has been another quality podcast
00:32:56 --> 00:32:58 production from bytes.com.