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Archived Insights: Europa Clipper, Gravitational Waves, and Black Hole Mysteries
In this special episode of Space Nuts , hosts Andrew Dunkley and Professor Fred Watson take a fascinating journey through some of the most compelling questions and discoveries in astronomy. As they explore the Europa Clipper mission, the nature of gravitational waves, and the enigmatic world of black holes, listeners are treated to a rich tapestry of cosmic knowledge. This episode originally aired in 2019.
Episode Highlights:
- Europa Clipper Mission: Andrew and Fred discuss NASA's exciting approval for the Europa Clipper mission, aimed at exploring Jupiter's icy moon Europa. They delve into the spacecraft's objectives, including investigating the moon's potential subsurface ocean and the challenges posed by Jupiter's intense radiation.
- Gravitational Waves Explained: The hosts explore the recent detection of gravitational waves, speculating on their origins, including a possible black hole-neutron star merger. They discuss the significance of these findings and the ongoing efforts of astronomers to understand the universe's most violent events.
- Black Hole Chris: Listener questions about the nature of black holes spark a lively discussion on topics such as infinite density, event horizons, and the complexities of capturing images of these cosmic phenomena. Andrew and Fred clarify misconceptions and provide insightful explanations.
- Space Travel and Relativity: The episode wraps up with an intriguing listener question about the effects of traveling near the speed of light. Andrew and Fred clarify how relativistic mass works and dispel myths surrounding the transformation of spaceships into black holes.
For more Space Nuts, including our continuously updating newsfeed and to listen to all our episodes, visit our website. (https://www.spacenutspodcast.com/) Follow us on social media at SpaceNutsPod on Facebook, X, YouTube Music Music, Tumblr, Instagram, and TikTok. We love engaging with our community, so be sure to drop us a message or comment on your favorite platform.
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Stay curious, keep looking up, and join us next time for more stellar insights and cosmic wonders. Until then, clear skies and happy stargazing.
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Episode link: https://play.headliner.app/episode/30915703?utm_source=youtube
00:00:00 --> 00:00:02 Hi, Andrew Dunley here. Fred and I are
00:00:02 --> 00:00:04 taking a little bit of a break over the
00:00:04 --> 00:00:06 Christmas New Year period just to catch
00:00:06 --> 00:00:09 our breath. We'll be back uh sometime
00:00:09 --> 00:00:11 around mid January. In the meantime,
00:00:11 --> 00:00:13 we've been digging through the archives
00:00:13 --> 00:00:16 at some of the most perplexing and
00:00:16 --> 00:00:18 popular episodes that we've done in
00:00:18 --> 00:00:22 recent times. So, sit back and enjoy.
00:00:22 --> 00:00:27 >> 15 seconds. Guidance is internal. 10 9
00:00:27 --> 00:00:29 ignition sequence start. Space Nuts.
00:00:29 --> 00:00:32 >> 5 4 3 2
00:00:32 --> 00:00:34 >> 1 2 3 4 5 2 1
00:00:34 --> 00:00:35 >> Space Nuts.
00:00:35 --> 00:00:38 >> Astronauts report. It feels good.
00:00:38 --> 00:00:40 >> Hi there and thanks for joining us on
00:00:40 --> 00:00:42 the Space Nuts podcast. My name is
00:00:42 --> 00:00:44 Andrew Dunley, your host. And joining
00:00:44 --> 00:00:47 me, as always, Professor Fred Watson,
00:00:47 --> 00:00:49 astronomer at large from the department
00:00:49 --> 00:00:52 of da da da da da. It's a pretty long
00:00:52 --> 00:00:54 title. That's what we'll call it from
00:00:54 --> 00:00:56 now on. Good day, Fred. You could call
00:00:56 --> 00:00:58 me the AAL because AAL.
00:00:58 --> 00:01:00 >> Yeah. When I was when I was astronomer
00:01:00 --> 00:01:03 in charge, I was AIC.
00:01:03 --> 00:01:05 The only trouble is AAL actually has
00:01:05 --> 00:01:07 another significant meaning in
00:01:07 --> 00:01:09 Australian astronomy because it doesn't
00:01:09 --> 00:01:11 only stand for astronomer at large. It
00:01:11 --> 00:01:13 also stands for Astronomy Australia
00:01:13 --> 00:01:16 Limited. So, uh, just throw that idea
00:01:16 --> 00:01:17 out. That's a rubbish idea. It'll just
00:01:17 --> 00:01:18 be a Yeah,
00:01:18 --> 00:01:21 >> I was once given the title URS.
00:01:22 --> 00:01:25 But anyway, um,
00:01:25 --> 00:01:27 some people will understand that.
00:01:27 --> 00:01:29 >> Yeah. You've got lovely friends, haven't
00:01:29 --> 00:01:29 you?
00:01:29 --> 00:01:31 >> I've got a lot of good friends. Yes.
00:01:31 --> 00:01:31 >> Yeah. Yeah.
00:01:31 --> 00:01:33 >> Now, today we're going to talk about
00:01:33 --> 00:01:35 some very exciting things. It looks like
00:01:35 --> 00:01:37 black holes are still in people's minds.
00:01:37 --> 00:01:40 So, we're going to be talking about um a
00:01:40 --> 00:01:41 couple of questions that have come in
00:01:41 --> 00:01:44 from people about infinite density. Uh,
00:01:44 --> 00:01:46 density. I keep getting it mixed up with
00:01:46 --> 00:01:48 destiny. I don't know why. might have
00:01:48 --> 00:01:50 been a Back to the Future movie that
00:01:50 --> 00:01:52 confused me on that front. Uh, and
00:01:52 --> 00:01:55 issues photographing a black hole. Why
00:01:55 --> 00:01:57 were they issues at all? And another
00:01:57 --> 00:02:00 question about space travel and near
00:02:00 --> 00:02:03 light speed travel. Uh, we're also going
00:02:03 --> 00:02:07 to look at um the cause of a
00:02:07 --> 00:02:08 gravitational wave that was detected
00:02:08 --> 00:02:10 recently. This is exciting because they
00:02:10 --> 00:02:12 think they've pinpointed an actual
00:02:12 --> 00:02:14 cause.
00:02:14 --> 00:02:15 And we're going to start off today,
00:02:15 --> 00:02:17 Fred, by talking about this rather
00:02:17 --> 00:02:19 exciting mission that's one step closer
00:02:19 --> 00:02:22 to happening. A mission to Jupiter's ice
00:02:22 --> 00:02:25 moon Europa. And that's what we'll start
00:02:25 --> 00:02:27 with this uh well this afternoon, this
00:02:27 --> 00:02:28 morning, tonight, this evening,
00:02:28 --> 00:02:30 yesterday,
00:02:30 --> 00:02:31 whenever
00:02:31 --> 00:02:34 >> whenever it is. Yeah, it's Yeah. So
00:02:34 --> 00:02:36 look, a terrific story, very good news
00:02:36 --> 00:02:39 from uh NASA that they um the powers
00:02:40 --> 00:02:42 that be within NASA have uh given the
00:02:42 --> 00:02:46 go-ahad um for a mission called Europa
00:02:46 --> 00:02:48 Clipper, which is is one of the uh
00:02:48 --> 00:02:52 missions that's been uh postulated or or
00:02:52 --> 00:02:55 sorry proposed is a better word for um
00:02:55 --> 00:02:56 exploring the moons of the outer
00:02:56 --> 00:02:58 planets. There are a number that are
00:02:58 --> 00:02:59 kind of on the on the table at the
00:03:00 --> 00:03:01 moment. Some further advanced than
00:03:01 --> 00:03:04 others, but Europa Clipper is pretty
00:03:04 --> 00:03:07 well advanced and as you can tell it's
00:03:07 --> 00:03:09 target, its main target is Jupiter's
00:03:09 --> 00:03:12 moon Europa, which is one of these um
00:03:12 --> 00:03:16 ocean moons, uh ice ocean moons. Uh we
00:03:16 --> 00:03:18 believe it has a covering of ice, and we
00:03:18 --> 00:03:20 don't know whether it's thin ice or
00:03:20 --> 00:03:21 thick ice. So that will be one of the
00:03:21 --> 00:03:23 things that Europa Clipper would find
00:03:23 --> 00:03:26 out. um and an ocean underneath it and
00:03:26 --> 00:03:30 and a rocky core. Uh so Europa Clipper I
00:03:30 --> 00:03:33 think they are talking about having it
00:03:33 --> 00:03:37 ready for launch in 2023 which is um you
00:03:37 --> 00:03:40 know fantastic if if they can do that.
00:03:40 --> 00:03:43 That's right. Uh but apparently that's
00:03:43 --> 00:03:46 um that's the the the the baseline
00:03:46 --> 00:03:48 commitment as it's called supports a
00:03:48 --> 00:03:51 launch readiness date by 2025. Um, it's
00:03:51 --> 00:03:53 all being done at the Jet Propulsion
00:03:53 --> 00:03:56 Laboratory in Pasadena. That's where the
00:03:56 --> 00:03:58 spacecraft will be built. So, they've
00:03:58 --> 00:04:02 got the go-ahad. It's um it's got a you
00:04:02 --> 00:04:06 know, the next step in uh in approval
00:04:06 --> 00:04:09 from NASA, which I think is a pretty
00:04:09 --> 00:04:12 solid one. So, I think we you and I in
00:04:12 --> 00:04:13
00:04:14 --> 00:04:16 will be talking a lot about Europa
00:04:16 --> 00:04:18 Clipper maybe. Yeah. and it and what
00:04:18 --> 00:04:20 will be the basis of the of the mission?
00:04:20 --> 00:04:22 Are they just going there to have a look
00:04:22 --> 00:04:23 because
00:04:23 --> 00:04:25 >> it is a bit like that but it's a very
00:04:25 --> 00:04:27 good look. Um so it's not going to land
00:04:28 --> 00:04:30 on Europa. It is a proposal to go into
00:04:30 --> 00:04:32 orbit around Europe actually to go into
00:04:32 --> 00:04:35 orbit around Jupiter. Uh and of course
00:04:35 --> 00:04:37 orbiting Jupiter is always hazardous
00:04:37 --> 00:04:40 because of the the intense um you know
00:04:40 --> 00:04:42 the intense uh radiation belts that
00:04:42 --> 00:04:45 Jupiter has. It's got a magnetic field
00:04:45 --> 00:04:47 thousands of times bigger than the
00:04:47 --> 00:04:48 earth's and has these high energy
00:04:48 --> 00:04:51 radiation belts around it that threaten
00:04:51 --> 00:04:54 to melt the inards of spacecraft. Uh so
00:04:54 --> 00:04:56 like uh the Juno mission which is
00:04:56 --> 00:04:59 currently in orbit around Jupiter, this
00:04:59 --> 00:05:02 uh Europa Clipper will go into a very uh
00:05:02 --> 00:05:08 elongated orbit um which will give it 45
00:05:08 --> 00:05:12 flybys of Europa. Uh, and the altitudes
00:05:12 --> 00:05:15 will vary from 2 kilometers to 25
00:05:15 --> 00:05:17 kilometers. So, it will really be
00:05:17 --> 00:05:18 skimming over the surface.
00:05:18 --> 00:05:19 >> Oh, will.
00:05:19 --> 00:05:21 >> And it's got this huge science package
00:05:21 --> 00:05:23 with all the kind of, you know, the
00:05:23 --> 00:05:25 goubbins that you would expect to find
00:05:25 --> 00:05:28 on board something like that, including
00:05:28 --> 00:05:30 a mass spectrometer,
00:05:30 --> 00:05:34 uh, which basically measures, you know,
00:05:34 --> 00:05:36 the the weights of atoms, as you might
00:05:36 --> 00:05:39 guess. Uh it um that is interesting
00:05:39 --> 00:05:42 because Europa like Saturn's moon
00:05:42 --> 00:05:44 Enceladus is thought to have although it
00:05:44 --> 00:05:45 hasn't really been properly confirmed
00:05:45 --> 00:05:49 but thought to have uh ice uh fountains
00:05:49 --> 00:05:52 coming out of it. Um which are water
00:05:52 --> 00:05:54 that's squirting up through its uh
00:05:54 --> 00:05:56 through its icy shell and instantly
00:05:56 --> 00:05:59 freezing. It's not frozen. But if you
00:05:59 --> 00:06:01 fly through it as Cassini did with
00:06:01 --> 00:06:03 Enceladus, then you can sample what the
00:06:03 --> 00:06:06 atomic makeup is. And so the mass
00:06:06 --> 00:06:09 spectrometer will help with that. Uh and
00:06:09 --> 00:06:12 also um it's got this ground penetrating
00:06:12 --> 00:06:16 radar and that's going to be crucial in
00:06:16 --> 00:06:19 characterizing Europa's crust um and
00:06:19 --> 00:06:22 revealing how much of you know the
00:06:22 --> 00:06:25 potential water within is oceanic as as
00:06:25 --> 00:06:27 is expected or whether it is just
00:06:27 --> 00:06:29 pockets of water as we find in
00:06:29 --> 00:06:31 Antarctica and indeed around the south
00:06:31 --> 00:06:33 pole of Mars. Will they be able to tell
00:06:33 --> 00:06:36 what kind of water it is?
00:06:36 --> 00:06:40 >> Um uh to to some extent they will. Um it
00:06:40 --> 00:06:44 it may require a bit of um you know
00:06:44 --> 00:06:46 inference from other measurements. But
00:06:46 --> 00:06:49 if you've got samples of ice crystals,
00:06:49 --> 00:06:52 uh then you can do exactly that. you can
00:06:52 --> 00:06:56 you know you can uh basically tell tell
00:06:56 --> 00:06:59 whether it's saline water or fresh water
00:06:59 --> 00:07:01 because you can see the you can measure
00:07:01 --> 00:07:04 the salt content of it. So like um
00:07:04 --> 00:07:07 Saturn's moon and Celadus uh which is
00:07:07 --> 00:07:09 actually quite rich in minerals and and
00:07:09 --> 00:07:11 it's the silicut in that that tells you
00:07:11 --> 00:07:13 that this water was once in contact with
00:07:13 --> 00:07:17 with rock. Uh, I think the Europa
00:07:17 --> 00:07:18 Clipper will be able to sample exactly
00:07:18 --> 00:07:21 those things too, assuming these plumes
00:07:21 --> 00:07:23 are real because they're then they're
00:07:23 --> 00:07:25 not well observed. There are there is
00:07:25 --> 00:07:27 evidence. I've seen images that that
00:07:27 --> 00:07:29 seem to show these plumes coming from
00:07:29 --> 00:07:31 Europa. Uh, assuming they're real, when
00:07:31 --> 00:07:33 they fly through, um, hopefully we will
00:07:33 --> 00:07:35 be able to tell what kind of water it is
00:07:35 --> 00:07:36 exactly.
00:07:36 --> 00:07:38 >> And will they be able to tell how much
00:07:38 --> 00:07:40 water there is underneath the surface?
00:07:40 --> 00:07:43 Yes, they will because that will very
00:07:43 --> 00:07:46 much be revealed by the um the ground
00:07:46 --> 00:07:49 penetrating radar in exactly the way
00:07:49 --> 00:07:51 that um one of the spacecraft in orbit
00:07:51 --> 00:07:53 around Mars. I think it was the I think
00:07:53 --> 00:07:54 it was might even have been Mars
00:07:54 --> 00:07:56 Reconnaissance Orbiter, I'm not sure,
00:07:56 --> 00:07:59 detected this lake of liquid water
00:07:59 --> 00:08:01 underneath the ice cap of the southern
00:08:01 --> 00:08:03 ice cap of Mars about a year ago. You
00:08:03 --> 00:08:06 and I spoke about it. Um, and they can
00:08:06 --> 00:08:08 tell exactly how much there is there
00:08:08 --> 00:08:10 because you you can see the boundary
00:08:10 --> 00:08:12 with this sort of radar. You can see the
00:08:12 --> 00:08:14 boundary between an ice surface and a
00:08:14 --> 00:08:16 water surface. And that's crucial to
00:08:16 --> 00:08:18 doing this. So, this mission won't
00:08:18 --> 00:08:21 actually be looking for life, but it
00:08:21 --> 00:08:25 will be looking for uh the potential for
00:08:25 --> 00:08:28 life to perhaps exist on a on a moon
00:08:28 --> 00:08:30 like this.
00:08:30 --> 00:08:33 >> Exactly. So, as the as the blurb um on
00:08:33 --> 00:08:36 the NASA website says, uh it will help
00:08:36 --> 00:08:38 scientists investigate the chemical
00:08:38 --> 00:08:40 makeup of Europa's potentially habitable
00:08:40 --> 00:08:43 environment while minimizing the need to
00:08:43 --> 00:08:45 drill through layers of ice. So, that
00:08:45 --> 00:08:46 what they're going to try and do is as
00:08:46 --> 00:08:49 much as they can from orbit.
00:08:49 --> 00:08:52 Um and then you know if there's like if
00:08:52 --> 00:08:54 they find lipids and amino acids and all
00:08:54 --> 00:08:56 this sort of thing in the uh in the
00:08:56 --> 00:08:59 plumes of ice coming coming from Europa
00:08:59 --> 00:09:01 then clearly the next step will be a
00:09:01 --> 00:09:03 lander that starts digging holes in the
00:09:03 --> 00:09:04 ice.
00:09:04 --> 00:09:04 >> Yes.
00:09:04 --> 00:09:06 >> I mean you know before you do that the
00:09:06 --> 00:09:07 first thing you need to know is how
00:09:08 --> 00:09:09 thick the ice is.
00:09:09 --> 00:09:09 >> Yes.
00:09:10 --> 00:09:14 >> If it's a couple of miles thick
00:09:14 --> 00:09:15 >> actually a couple of miles is better
00:09:16 --> 00:09:17 than what they're expecting.
00:09:17 --> 00:09:20 >> Oh is that right? more like 25 or 30
00:09:20 --> 00:09:23 >> miles or kilometers. That's right.
00:09:23 --> 00:09:26 Choose your units. Um yes. So yes, a a
00:09:26 --> 00:09:29 thinish layer of ice would be pretty
00:09:29 --> 00:09:32 pretty um good to you know to cope with.
00:09:32 --> 00:09:34 You could probably do that. I mean by
00:09:34 --> 00:09:35 thin I mean less than a kilometer
00:09:35 --> 00:09:36 probably.
00:09:36 --> 00:09:39 >> Yes. But the likelihood is it's it's
00:09:39 --> 00:09:40 probably more. But I guess we'll we'll
00:09:40 --> 00:09:42 have to wait and see.
00:09:42 --> 00:09:44 >> The thing is and um Europa is covered in
00:09:44 --> 00:09:45 all these cracks that are that are
00:09:45 --> 00:09:47 brownish in color. Yes,
00:09:47 --> 00:09:49 >> that's thought to be the effect of
00:09:49 --> 00:09:52 sunlight on brine on basically on salt
00:09:52 --> 00:09:54 water. So, you've already got a hint
00:09:54 --> 00:09:57 there that it's probably a salty ocean
00:09:57 --> 00:09:58 underneath the surface.
00:09:58 --> 00:10:00 >> Well, salt's probably not that uncommon
00:10:00 --> 00:10:02 in the universe really. Um,
00:10:02 --> 00:10:03 >> that's right. It's not.
00:10:03 --> 00:10:05 >> It's one of one of the base materials,
00:10:05 --> 00:10:08 isn't it? Uh, of course, this doesn't
00:10:08 --> 00:10:09 guarantee they're actually going to go.
00:10:10 --> 00:10:12 This is just another step forward in the
00:10:12 --> 00:10:14 approval process. It it does. It does.
00:10:14 --> 00:10:16 Correct. very longitudinal process and
00:10:16 --> 00:10:18 they have to get over a lot of hurdles
00:10:18 --> 00:10:19 before they actually hit the launch
00:10:19 --> 00:10:22 button. So, uh hopefully they're um
00:10:22 --> 00:10:24 they're going to get there and u it's
00:10:24 --> 00:10:26 it's a long trip to
00:10:26 --> 00:10:27 >> Yes, it is. That's the other thing.
00:10:27 --> 00:10:29 >> So, they got to time it right. They've
00:10:29 --> 00:10:30 got to get in the right place at the
00:10:30 --> 00:10:31 right time.
00:10:31 --> 00:10:33 >> Exactly. All of the above. That's right.
00:10:33 --> 00:10:36 So, at least what it you know, at least
00:10:36 --> 00:10:37 uh it's not a knock back. That's the
00:10:37 --> 00:10:38 good news.
00:10:38 --> 00:10:40 >> Yes, indeed. All right. Well, we'll keep
00:10:40 --> 00:10:42 an eye on this story because I'm sure
00:10:42 --> 00:10:43 there'll be more to report in the not
00:10:44 --> 00:10:46 too distant future about a mission to
00:10:46 --> 00:10:49 Europa. You're listening to Space Nuts
00:10:49 --> 00:10:53 with Andrew Dunley and Fred Watson.
00:10:53 --> 00:10:54 Let's take a break from the show to tell
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00:12:46 --> 00:12:48 >> Roger, you're here also.
00:12:48 --> 00:12:50 >> Space nuts. Now, Fred, we've uh
00:12:50 --> 00:12:52 discussed
00:12:52 --> 00:12:55 uh gravitational waves before and a few
00:12:55 --> 00:12:57 of those have been detected in recent
00:12:57 --> 00:13:01 times. Uh the problem with them is what
00:13:01 --> 00:13:04 is the cause? And now in a recently
00:13:04 --> 00:13:07 detected gravitational wave, they think
00:13:07 --> 00:13:10 they've got a candidate. That's that's
00:13:10 --> 00:13:11 right. This is so this is, you know,
00:13:11 --> 00:13:15 it's a an ongoing story. Uh what I like
00:13:15 --> 00:13:16 about this story is it's got a nice
00:13:16 --> 00:13:19 Australian component because there is um
00:13:19 --> 00:13:22 there's a a a basically a a
00:13:22 --> 00:13:24 collaboration here in Australia which is
00:13:24 --> 00:13:26 called Osgrav uh which is about
00:13:26 --> 00:13:28 gravitational waves. It's a you know
00:13:28 --> 00:13:30 kind of fairly predictable name but um
00:13:30 --> 00:13:32 it includes people from the Australian
00:13:32 --> 00:13:34 univers national university and I think
00:13:34 --> 00:13:36 University of Western Australia other
00:13:36 --> 00:13:38 places which are strong in gravitational
00:13:38 --> 00:13:41 wave astronomy. So um it's very nice
00:13:41 --> 00:13:43 that it has this Australian component.
00:13:43 --> 00:13:47 So what's the story? Well uh the large
00:13:47 --> 00:13:49 uh sorry the laser interferometer
00:13:49 --> 00:13:51 gravitational wave observatory otherwise
00:13:51 --> 00:13:55 known as LIGO um has been operating
00:13:55 --> 00:13:59 since uh 2015 in its uh sort of current
00:13:59 --> 00:14:01 state. It's actually technically called
00:14:01 --> 00:14:03 advanced LIGO because I think it took 15
00:14:03 --> 00:14:05 years of de of development to get to
00:14:05 --> 00:14:08 this stage. But that but they have uh
00:14:08 --> 00:14:11 now not quite regularly but at fairly
00:14:12 --> 00:14:14 infrequent intervals sorry fairly
00:14:14 --> 00:14:17 moderately moderate intervals let me put
00:14:17 --> 00:14:18 it that way they've been detecting
00:14:18 --> 00:14:21 gravitational wave events and for the
00:14:21 --> 00:14:22 last couple of years they've had an
00:14:22 --> 00:14:24 additional string to their bow. Remember
00:14:24 --> 00:14:25 there are two of these detectors at
00:14:25 --> 00:14:29 opposite corners of the United States um
00:14:29 --> 00:14:33 which um you need because uh otherwise
00:14:33 --> 00:14:34 you've got no idea where these things
00:14:34 --> 00:14:36 come from or even if they're real. you
00:14:36 --> 00:14:38 need to see the gravitational wave pass
00:14:38 --> 00:14:40 one and then the other with the right
00:14:40 --> 00:14:42 kind of time interval in between. Um but
00:14:42 --> 00:14:44 they've been joined in the last few
00:14:44 --> 00:14:47 years by something called uh uh Virgo
00:14:47 --> 00:14:49 which uh in fact I think it's called
00:14:49 --> 00:14:51 advanced Virgo like advanced LIGO. Virgo
00:14:51 --> 00:14:53 is an Italian gravitational wave
00:14:53 --> 00:14:55 detector. And of course having three
00:14:55 --> 00:14:58 detectors widely spread over the surface
00:14:58 --> 00:14:59 of the earth means you can pinpoint
00:14:59 --> 00:15:01 things much more accurately in in terms
00:15:01 --> 00:15:03 of the direction in which these
00:15:03 --> 00:15:05 gravitational waves come in from. tri
00:15:05 --> 00:15:07 triangulating the signal.
00:15:07 --> 00:15:10 >> Exactly. That's exactly what it is. Um,
00:15:10 --> 00:15:12 what's interesting about this one though
00:15:12 --> 00:15:16 is that the signal seems to be from a
00:15:16 --> 00:15:21 black hole absorbing a neutron star.
00:15:21 --> 00:15:24 >> Um, we actually had a false alarm on
00:15:24 --> 00:15:27 this, which is embarrassing because um,
00:15:27 --> 00:15:28 my book has just gone to the printer
00:15:28 --> 00:15:30 saying, "Yes, we've observed a neutron
00:15:30 --> 00:15:33 star being absorbed by a black hole."
00:15:33 --> 00:15:36 Um, and that that I think disappeared
00:15:36 --> 00:15:38 because it turned out to be um
00:15:38 --> 00:15:40 terrestrial noise. It was sort of, you
00:15:40 --> 00:15:41 know, so I don't know whether it was a
00:15:41 --> 00:15:44 train going underneath
00:15:44 --> 00:15:44 probably
00:15:44 --> 00:15:46 >> or Yeah, something like that. That's the
00:15:46 --> 00:15:48 usual story, isn't it? A microwave oven.
00:15:48 --> 00:15:51 Um that was earlier this year. And and
00:15:51 --> 00:15:54 that um has now gone away, but it looks
00:15:54 --> 00:15:57 as though this one might actually be the
00:15:57 --> 00:15:59 real thing, a black hole and a neutron
00:15:59 --> 00:16:01 star. Uh we've had two black holes
00:16:01 --> 00:16:04 merging. Uh that's that's probably been
00:16:04 --> 00:16:07 the commonest source of gravitational
00:16:07 --> 00:16:08 waves. There've been several of those.
00:16:08 --> 00:16:10 We've had a couple of neutron stars
00:16:10 --> 00:16:12 merging as well. And that actually comes
00:16:12 --> 00:16:15 with celestial fireworks that you can
00:16:15 --> 00:16:18 observe with other types of telescope
00:16:18 --> 00:16:20 like neutrino telescopes, visible light
00:16:20 --> 00:16:22 telescopes, radio telescopes, x-ray
00:16:22 --> 00:16:25 telescopes, all of the above. Um and
00:16:25 --> 00:16:27 that was a big story actually late last
00:16:27 --> 00:16:30 year if I remember rightly. But um until
00:16:30 --> 00:16:34 now we haven't had a confirmed um uh
00:16:34 --> 00:16:36 observation of a neutron star being
00:16:36 --> 00:16:38 absorbed by a black hole and we still
00:16:38 --> 00:16:41 don't have it's still a bit speculative
00:16:41 --> 00:16:44 but from the masses that are inferred by
00:16:44 --> 00:16:45 the signal and remember what you get is
00:16:45 --> 00:16:49 this weird gravitational chirp uh it's
00:16:49 --> 00:16:53 the frequency of a sound wave going
00:16:53 --> 00:16:55 as the two things come together. Um, and
00:16:55 --> 00:16:57 it's that that gives you all the details
00:16:57 --> 00:16:59 of what it is that that are colliding.
00:16:59 --> 00:17:02 The suspicion is it's two objects, one
00:17:02 --> 00:17:05 of which is three solar masses and the
00:17:05 --> 00:17:09 other is five solar masses. I think I'm
00:17:09 --> 00:17:11 right in saying that. I uh should check
00:17:11 --> 00:17:14 those numbers. But anyway, uh that is
00:17:14 --> 00:17:17 the current uh expectation of what is
00:17:17 --> 00:17:20 colliding. So something three solar
00:17:20 --> 00:17:23 masses would have to be a neutron star
00:17:23 --> 00:17:26 because it's too lightweight uh to be a
00:17:26 --> 00:17:29 black hole. And so that is what's making
00:17:30 --> 00:17:33 this interesting. What's what's perhaps
00:17:33 --> 00:17:36 um a bit surprising
00:17:36 --> 00:17:39 uh it's is that you might expect there
00:17:39 --> 00:17:42 to be once again uh radiation coming
00:17:42 --> 00:17:43 from this of you know not just
00:17:43 --> 00:17:46 gravitational radiation but uh noise in
00:17:46 --> 00:17:50 the x-ray spectrum or neutron neutrinos
00:17:50 --> 00:17:52 uh particles things of that sort but it
00:17:52 --> 00:17:57 but it hasn't been observed and um the
00:17:57 --> 00:18:00 one of the Australian astronomers uh Um
00:18:00 --> 00:18:02 I've forgotten her first name. That's
00:18:02 --> 00:18:04 embarrassing, isn't it? Susan Susan
00:18:04 --> 00:18:07 Scott. Uh she's at um ANU, Australian
00:18:07 --> 00:18:12 National University. Uh she says that uh
00:18:12 --> 00:18:14 I if she well what she says is we've
00:18:14 --> 00:18:15 looked for light signatures of the
00:18:16 --> 00:18:17 event, but no one has found any up to
00:18:17 --> 00:18:19 this point. That indicates that if it is
00:18:19 --> 00:18:22 a black hole and a neutron star, then
00:18:22 --> 00:18:24 very likely the neutron star has been
00:18:24 --> 00:18:27 swallowed whole by the black hole. Uh uh
00:18:27 --> 00:18:29 he said and she says this could happen
00:18:30 --> 00:18:32 if the objects were of different masses.
00:18:32 --> 00:18:35 So it's the smaller object gets sucked
00:18:35 --> 00:18:37 in more quickly and and is swallowed
00:18:37 --> 00:18:39 whole. So you know it's not strung out
00:18:39 --> 00:18:43 into into this um mess of material uh
00:18:43 --> 00:18:46 that does emit um signals in the
00:18:46 --> 00:18:49 electromagnetic uh wave bands. Uh if it
00:18:49 --> 00:18:52 gets sucked in hole maybe you don't get
00:18:52 --> 00:18:53 any signal at all except for the
00:18:53 --> 00:18:55 gravitational wave signal.
00:18:55 --> 00:18:55 extraordinary.
00:18:55 --> 00:18:59 >> How how sudden would the impact be? I
00:18:59 --> 00:19:01 mean, you know, neutron stars, we've
00:19:01 --> 00:19:03 talked about them, and they're pretty
00:19:03 --> 00:19:06 volatile individuals and and quite
00:19:06 --> 00:19:08 dense. Um,
00:19:08 --> 00:19:10 >> quite quite dense is just a slight
00:19:10 --> 00:19:12 understatement there.
00:19:12 --> 00:19:16 >> Yes, indeed. Um, so, so
00:19:16 --> 00:19:18 I imagine it would be quite a cathlymic
00:19:18 --> 00:19:19 collision.
00:19:19 --> 00:19:22 >> Yeah, that's right. Um in fact so when
00:19:22 --> 00:19:25 you've got two black holes um what you
00:19:25 --> 00:19:26 get at the end of it is a more massive
00:19:26 --> 00:19:28 black hole
00:19:28 --> 00:19:30 >> uh and um you're talking there though
00:19:30 --> 00:19:32 about
00:19:32 --> 00:19:34 you know infinitely small infinite
00:19:34 --> 00:19:37 decimally small points merging uh their
00:19:37 --> 00:19:39 event horizon there are two event
00:19:39 --> 00:19:41 horizons merge as well and you get
00:19:41 --> 00:19:43 something called a ring down where the
00:19:43 --> 00:19:45 event horizon itself vibrates
00:19:46 --> 00:19:48 um I think with a neutron star you
00:19:48 --> 00:19:50 wouldn't have the event horizon
00:19:50 --> 00:19:52 But it will be possible for the the
00:19:52 --> 00:19:54 neutron star just basically to disappear
00:19:54 --> 00:19:55 over the black holes event horizon. You
00:19:55 --> 00:19:58 don't see anything. But neutron stars
00:19:58 --> 00:19:59 themselves as you and I have talked
00:19:59 --> 00:20:01 about many times are active in the sense
00:20:01 --> 00:20:03 that they've got highly intense magnetic
00:20:03 --> 00:20:05 fields on their surfaces and they beam
00:20:06 --> 00:20:08 this radiation out which we see as as
00:20:08 --> 00:20:10 pulsars. So they're not they're not
00:20:10 --> 00:20:12 particularly quiet things. I mean, this
00:20:12 --> 00:20:15 thing could be a pulsar whose lighthouse
00:20:15 --> 00:20:18 beam of radiation is missing the Earth,
00:20:18 --> 00:20:20 if if I can put it that way, because the
00:20:20 --> 00:20:22 only reason we see pulsars is when
00:20:22 --> 00:20:25 you've got a neutron star whose uh beams
00:20:25 --> 00:20:27 of radiation from their poles actually
00:20:27 --> 00:20:29 sweeps across the Earth. And that, of
00:20:29 --> 00:20:31 course, is a particular uh circumstance.
00:20:31 --> 00:20:34 Maybe this one wasn't like that and it's
00:20:34 --> 00:20:37 just got chewed up uh and we haven't kn
00:20:37 --> 00:20:39 we haven't seen it its demise other than
00:20:39 --> 00:20:41 in the gravitational waves. I think
00:20:41 --> 00:20:43 there'll be more about this story Andrew
00:20:43 --> 00:20:46 and um I hope you and I can bring it to
00:20:46 --> 00:20:48 our uh our space nuts listener or
00:20:48 --> 00:20:50 listeners
00:20:50 --> 00:20:52 >> our fraternity.
00:20:52 --> 00:20:55 >> Yes. Uh well it's it um you know the the
00:20:55 --> 00:20:58 more we can gather in terms of data uh
00:20:58 --> 00:21:01 on gravitational waves the the more we
00:21:01 --> 00:21:04 will learn and who knows what sort of
00:21:04 --> 00:21:06 problems it could solve down the track.
00:21:06 --> 00:21:07 So
00:21:07 --> 00:21:09 >> exactly it's always my comment that you
00:21:09 --> 00:21:11 never know what you're what you've
00:21:11 --> 00:21:13 setting in store for the future from all
00:21:13 --> 00:21:13 this knowledge.
00:21:14 --> 00:21:16 >> Exactly. Yeah. I mean you just gather
00:21:16 --> 00:21:18 the knowledge one day it might just go
00:21:18 --> 00:21:19 you know a penny will drop with someone
00:21:20 --> 00:21:21 else maybe
00:21:21 --> 00:21:23 >> a generation down the track. Who knows?
00:21:23 --> 00:21:24 It's it's all useful.
00:21:24 --> 00:21:26 >> And even if it's not, it's good to be
00:21:26 --> 00:21:28 able to gather it and
00:21:28 --> 00:21:30 >> well, they use it some some way.
00:21:30 --> 00:21:32 >> It it's um you know, all these things
00:21:32 --> 00:21:34 are constantly testing Einstein's theory
00:21:34 --> 00:21:38 of relativity. And that's um very
00:21:38 --> 00:21:39 important because we know there's
00:21:39 --> 00:21:40 something wrong with it, but we haven't
00:21:40 --> 00:21:42 found anything wrong with it yet. Even
00:21:42 --> 00:21:44 though it's been tested within an inch
00:21:44 --> 00:21:47 of its life, it still holds up.
00:21:47 --> 00:21:49 >> Yeah. Fascinating. All right. Stop.
00:21:49 --> 00:21:51 >> You're listening to the Space Nuts
00:21:51 --> 00:21:53 podcast with Andrew Dunley and Fred
00:21:53 --> 00:21:56 Watson.
00:21:56 --> 00:21:58 >> Okay, we checked all four systems and
00:21:58 --> 00:21:59 being with the girls.
00:21:59 --> 00:22:00 >> Space Nuts.
00:22:00 --> 00:22:02 >> Now, Fred, I do want to shout out once
00:22:02 --> 00:22:06 again to our patrons. Uh, the number 39
00:22:06 --> 00:22:08 now. Uh, thank you so much for
00:22:08 --> 00:22:11 supporting the Space Nuts podcast. We so
00:22:11 --> 00:22:13 appreciate it. And if you're interested
00:22:13 --> 00:22:15 in becoming a patron, you can do so at
00:22:15 --> 00:22:17 patreon.com/spacenuts.
00:22:17 --> 00:22:21 That's patreon.com/spacenuts.
00:22:21 --> 00:22:24 And uh thank you to everybody who has
00:22:24 --> 00:22:27 joined the Spacenuts podcast group. They
00:22:27 --> 00:22:29 number in their hundreds now, Fred.
00:22:29 --> 00:22:31 >> We've only had the page going for a bit
00:22:31 --> 00:22:33 over a week and already we've we've
00:22:33 --> 00:22:35 tracked the century.
00:22:35 --> 00:22:38 >> And have over 100 people that are all
00:22:38 --> 00:22:40 Space Nuts fans who are all now talking
00:22:40 --> 00:22:42 to each other and uh answering each
00:22:42 --> 00:22:45 other's questions and uh having a fair
00:22:45 --> 00:22:47 bit of fun. So, it's I'm so pleased we
00:22:47 --> 00:22:49 were able to put um those people
00:22:49 --> 00:22:51 together and uh who knows friends
00:22:51 --> 00:22:54 friendships may be forged
00:22:54 --> 00:22:56 >> um or collaborations that might solve
00:22:56 --> 00:22:58 some of the mysteries of the universe.
00:22:58 --> 00:23:00 Who knows? Uh that would be a lovely
00:23:00 --> 00:23:03 legacy. I think uh let's um
00:23:03 --> 00:23:05 >> and of course if you would like to be a
00:23:05 --> 00:23:07 uh a member of the Space Nuts podcast
00:23:07 --> 00:23:10 group um just find it. It's on Facebook
00:23:10 --> 00:23:12 uh Space Nuts podcast group in your
00:23:12 --> 00:23:14 search engine. And um yes, just ask to
00:23:14 --> 00:23:17 join and we will click the approve
00:23:17 --> 00:23:19 button. Everybody seems to be
00:23:19 --> 00:23:21 like-minded and enjoying themselves. So
00:23:21 --> 00:23:23 uh that's what it's all about.
00:23:23 --> 00:23:27 Now Fred, some questions, if you will.
00:23:27 --> 00:23:29 Um hello again, fellow nutters. I have a
00:23:29 --> 00:23:32 question. I'm hoping you can help me um
00:23:32 --> 00:23:35 understanding an old chestnut. Black
00:23:35 --> 00:23:37 holes. If a black hole is an infinite
00:23:37 --> 00:23:39 dense point, why does it have a
00:23:39 --> 00:23:41 diameter? I don't understand why
00:23:41 --> 00:23:43 astronomers refer to black holes by
00:23:43 --> 00:23:45 their size in terms of diameter when
00:23:45 --> 00:23:47 it's meant to be a point of infinite des
00:23:47 --> 00:23:49 uh density. Are they mistakenly
00:23:49 --> 00:23:52 referring to the event horizon? Mario
00:23:52 --> 00:23:54 from Melbourne. Hello Mario. Thanks for
00:23:54 --> 00:23:57 the question. And the answer is yes.
00:23:57 --> 00:23:58 Thank you Mario. Thanks for the
00:23:58 --> 00:24:02 question. Um Mario then goes on to you
00:24:02 --> 00:24:04 know everything he says is absolutely
00:24:04 --> 00:24:07 right that um uh if you've got a a a
00:24:07 --> 00:24:10 point of infinite density it's got zero
00:24:10 --> 00:24:13 dimensions so you can't refer to its
00:24:13 --> 00:24:15 diameter. Uh what you can refer to is
00:24:15 --> 00:24:19 its mass because the the mass is uh is
00:24:19 --> 00:24:22 variable. uh but the fact that it has no
00:24:22 --> 00:24:25 volume means that when you you know when
00:24:25 --> 00:24:26 you look at the mass per unit volume
00:24:26 --> 00:24:28 you've got something of infinite density
00:24:28 --> 00:24:31 which is how density is defined. So
00:24:31 --> 00:24:33 Mario is absolutely right. Uh what does
00:24:33 --> 00:24:36 vary though with the mass is the event
00:24:36 --> 00:24:37 horizon the diameter of the event
00:24:37 --> 00:24:39 horizon which you and I have spoken
00:24:39 --> 00:24:44 about before. Um it's uh uh it's a a
00:24:44 --> 00:24:47 quantity that I I suppose is important
00:24:47 --> 00:24:51 because if we are observing an um a
00:24:51 --> 00:24:53 black hole as we did with the event
00:24:53 --> 00:24:54 horizon telescope then that's what you
00:24:54 --> 00:24:56 see. Uh so a big one's going to be
00:24:56 --> 00:24:58 easier to observe than a smaller one and
00:24:58 --> 00:25:00 that's why a super massive black hole uh
00:25:00 --> 00:25:02 in the center of a galaxy called M87 was
00:25:02 --> 00:25:04 chosen for the the first target for that
00:25:04 --> 00:25:07 event horizon telescope. But no Mario
00:25:07 --> 00:25:09 you're quite right. Um it is that uh
00:25:09 --> 00:25:11 astronomers when if they talk about the
00:25:11 --> 00:25:13 diameter of a black hole and that
00:25:13 --> 00:25:15 probably includes me as well uh are
00:25:15 --> 00:25:17 actually really referring to the event
00:25:17 --> 00:25:18 horizon because that's the that's the
00:25:18 --> 00:25:21 parameter. And I love the way Mario
00:25:21 --> 00:25:23 signs off by saying thanks in advance to
00:25:23 --> 00:25:26 Dave and Fred although he does say aka
00:25:26 --> 00:25:28 Andrew.
00:25:28 --> 00:25:29 >> Yes, that one's going to stick for a
00:25:29 --> 00:25:35 while. Sorry to say. Thank you Mario.
00:25:35 --> 00:25:37 Moving on. Uh hi Andrew and Fred. It's
00:25:37 --> 00:25:39 Andrew from Newcastle with another
00:25:39 --> 00:25:41 question if I may. Just watched a doco
00:25:41 --> 00:25:43 on the quest to capture the first
00:25:43 --> 00:25:45 photograph of a black hole. Uh rather
00:25:45 --> 00:25:48 accurately the shadow of a black hole as
00:25:48 --> 00:25:50 Fred so eloquently explained and I
00:25:50 --> 00:25:53 didn't understand one thing amongst
00:25:53 --> 00:25:54 others of course with the multiple
00:25:54 --> 00:25:56 observatories around the world and the
00:25:56 --> 00:25:58 use of atomic clocks to synchronize the
00:25:58 --> 00:26:01 data acquisition. Why were they uh on
00:26:01 --> 00:26:04 tender hooks uh regarding the weather at
00:26:04 --> 00:26:07 all the sites with bad weather at just
00:26:07 --> 00:26:09 one putting the whole venture in peril?
00:26:09 --> 00:26:11 I understand from the show and other
00:26:11 --> 00:26:13 sources that they were collecting radio
00:26:13 --> 00:26:15 wavelength data and I thought that this
00:26:15 --> 00:26:17 was unaffected by the weather and
00:26:17 --> 00:26:19 atmospheric conditions. I thought that
00:26:19 --> 00:26:22 was the intrinsic beauty of radio
00:26:22 --> 00:26:24 astronomy day and night rain and shine.
00:26:24 --> 00:26:27 Hope you can enlighten me. Wait for it
00:26:27 --> 00:26:30 but over the radio. Dear, oh dear. H
00:26:30 --> 00:26:32 Andrew Broadhost. Thank you, Andrew.
00:26:32 --> 00:26:34 >> That's a great question, Andrew. Leave
00:26:34 --> 00:26:37 the jokes to me, man.
00:26:37 --> 00:26:39 >> Yeah. Well, I always leave them to you.
00:26:39 --> 00:26:41 So,
00:26:41 --> 00:26:43 >> um if they're good.
00:26:43 --> 00:26:45 >> Oh gosh. When was the last Oh, never
00:26:46 --> 00:26:47 mind.
00:26:48 --> 00:26:49 Uh Andrew's on the money there is, you
00:26:49 --> 00:26:51 know, I thought radio waves were
00:26:51 --> 00:26:53 unaffected by the weather. And the
00:26:53 --> 00:26:54 answer is that radio waves come in
00:26:54 --> 00:26:58 different flavors. Uh and so what you
00:26:58 --> 00:27:01 might call low frequency radio waves um
00:27:01 --> 00:27:03 which are still relatively you know
00:27:03 --> 00:27:05 they're way outside the medium wave band
00:27:05 --> 00:27:07 of radio and things of that sort but low
00:27:08 --> 00:27:10 frequency in radio astronomy um I guess
00:27:10 --> 00:27:12 goes up to a couple of gigahertz or
00:27:12 --> 00:27:15 something like that. Um those are
00:27:15 --> 00:27:17 largely unaffected by weather. That's
00:27:18 --> 00:27:19 absolutely right. So that's why it can
00:27:19 --> 00:27:21 be pouring down at parks at the radio
00:27:22 --> 00:27:23 dish there and the astronomers are still
00:27:23 --> 00:27:25 happily observing through that. But the
00:27:25 --> 00:27:27 event horizon telescope used higher
00:27:27 --> 00:27:31 frequencies. Uh in fact one of the
00:27:31 --> 00:27:33 telescopes that was incorporated into it
00:27:33 --> 00:27:35 was ALMA the Atakama large millimeter
00:27:35 --> 00:27:38 array which has featured very uh very
00:27:38 --> 00:27:40 widely on space notes. That is a high
00:27:40 --> 00:27:42 frequency
00:27:42 --> 00:27:46 uh radio array. In fact they have
00:27:46 --> 00:27:49 receivers that go up to uh more than 900
00:27:49 --> 00:27:51 gigahertz. So that's like, you know,
00:27:51 --> 00:27:53 nearly a thousand times higher
00:27:53 --> 00:27:54 frequencies than what we've just been
00:27:54 --> 00:27:56 talking about. And at those sorts of
00:27:56 --> 00:27:59 frequencies, uh, the weather plays a
00:27:59 --> 00:28:02 very important role because water vapor
00:28:02 --> 00:28:05 actually dramatically absorbs the
00:28:05 --> 00:28:07 microwave signals. And that's what
00:28:08 --> 00:28:09 experienced that watching satellite
00:28:09 --> 00:28:12 television. If there is a storm and it
00:28:12 --> 00:28:14 rains heavily, the wavelengths of the
00:28:14 --> 00:28:17 raindrops can absorb the signals from
00:28:17 --> 00:28:19 the satellite and you get nothing.
00:28:19 --> 00:28:21 That's interesting. I've never tried to
00:28:21 --> 00:28:24 watch satellite television, so that's
00:28:24 --> 00:28:25 good thing to know.
00:28:25 --> 00:28:26 >> Um,
00:28:26 --> 00:28:27 >> it's one of the pitfalls.
00:28:28 --> 00:28:29 >> Yes. Yes. In fact, I seldom watch
00:28:29 --> 00:28:31 television at all. So, that's probably
00:28:31 --> 00:28:35 why. Um, but but the bottom line is um,
00:28:35 --> 00:28:38 you know, it's why facilities like ALMA
00:28:38 --> 00:28:40 and some of the other radio telescopes
00:28:40 --> 00:28:44 that were used uh to to to be become the
00:28:44 --> 00:28:45 event horizon telescope, it's why
00:28:45 --> 00:28:48 they're all at high altitudes. Alma is
00:28:48 --> 00:28:51 at almost 5 meters above sea level.
00:28:51 --> 00:28:55 Um that's you know 15 16 feet and at
00:28:55 --> 00:28:57 that height there is very little water
00:28:57 --> 00:28:59 vapor in the atmosphere. Uh but you can
00:29:00 --> 00:29:01 still get weather and that's why they
00:29:01 --> 00:29:03 were indeed on tent hooks about the
00:29:03 --> 00:29:05 weather because they don't want any of
00:29:05 --> 00:29:09 these if you lose one of those arrays
00:29:09 --> 00:29:10 and I think there were eight of them
00:29:10 --> 00:29:12 that came together all around one
00:29:12 --> 00:29:14 hemisphere of the earth uh to to to make
00:29:14 --> 00:29:17 up the event horizon telescope. if you
00:29:17 --> 00:29:19 lose one of them, you lose a significant
00:29:19 --> 00:29:21 amount of your ability to reconstruct
00:29:21 --> 00:29:23 the image that they're seeing. Uh, and
00:29:23 --> 00:29:25 so that was why they were worried that
00:29:25 --> 00:29:26 the the weather on just one of them
00:29:26 --> 00:29:30 might be uh moist uh or damper than they
00:29:30 --> 00:29:31 can cope with and that would have
00:29:31 --> 00:29:33 screwed up the whole thing. But as it
00:29:33 --> 00:29:35 happened, it wasn't. It didn't happen
00:29:35 --> 00:29:36 and it was great.
00:29:36 --> 00:29:38 >> They got global good weather.
00:29:38 --> 00:29:40 >> They did global good weather at these
00:29:40 --> 00:29:41 high altitude sites. That's right.
00:29:41 --> 00:29:42 >> Did the job. All right, there you are,
00:29:42 --> 00:29:45 Andrew. Uh, thank you for your question.
00:29:45 --> 00:29:47 And we've got one more we'll squeeze in
00:29:47 --> 00:29:50 from John Spoo. I hope I pronounced that
00:29:50 --> 00:29:52 correctly. John, thanks for your
00:29:52 --> 00:29:53 question. Hi, I have a question that's
00:29:53 --> 00:29:55 been bugging me for some time and I need
00:29:55 --> 00:29:58 an expert to help me out. I think we
00:29:58 --> 00:30:00 should stop there, Fred.
00:30:00 --> 00:30:01 >> There's nobody here, is there? Who's
00:30:01 --> 00:30:03 that? Hang on, I'll go and see if I can
00:30:03 --> 00:30:04 find somebody.
00:30:04 --> 00:30:05 >> Maybe the cat could probably answer this
00:30:05 --> 00:30:09 one. Now, um, imagine a spaceship
00:30:09 --> 00:30:11 traveling close to the speed of light.
00:30:11 --> 00:30:12 Disregarding that we don't have that
00:30:12 --> 00:30:15 sort of propulsion just yet, would the
00:30:15 --> 00:30:18 increase in its relativistic mass at
00:30:18 --> 00:30:20 some point turn the spaceship into a
00:30:20 --> 00:30:24 black hole? And if so, would that spell
00:30:24 --> 00:30:26 the end of the ship and its crew? Or
00:30:26 --> 00:30:27 would they be able to slow down to
00:30:28 --> 00:30:30 reverse the process? What a great
00:30:30 --> 00:30:30 question.
00:30:30 --> 00:30:32 >> It is a fantastic question. Do you want
00:30:32 --> 00:30:33 to have a go at it?
00:30:33 --> 00:30:35 >> Uh, the answer is no.
00:30:35 --> 00:30:37 >> It is. You got right. Yeah, you were
00:30:37 --> 00:30:39 right on the money there. See, see,
00:30:39 --> 00:30:40 there is an expert. It's called Andrew
00:30:40 --> 00:30:42 Dunley or Dave
00:30:42 --> 00:30:45 >> 50/50 chance.
00:30:45 --> 00:30:49 >> Um, it's a great question and it it the
00:30:49 --> 00:30:52 answer is a little bit prosaic I think
00:30:52 --> 00:30:55 and that is that in the in the rest
00:30:56 --> 00:30:58 frame of the spacecraft
00:30:58 --> 00:30:59 you know so if you're on the spacecraft
00:31:00 --> 00:31:01 and you're going at almost the speed of
00:31:01 --> 00:31:05 light your mass doesn't change. It's
00:31:05 --> 00:31:09 only in the rest frame of a a stationary
00:31:09 --> 00:31:10 observer. And by that I mean somebody
00:31:10 --> 00:31:12 watching you go past. Somebody watches
00:31:12 --> 00:31:15 you hurl past and your mass gets very
00:31:15 --> 00:31:19 much higher to the observer.
00:31:19 --> 00:31:22 >> But to the the inhabitants of the
00:31:22 --> 00:31:24 spacecraft or the spacecraft itself,
00:31:24 --> 00:31:25 your mass doesn't change.
00:31:25 --> 00:31:27 >> It's you're still normal.
00:31:27 --> 00:31:29 >> Still normal. Yeah. So and the same
00:31:29 --> 00:31:31 story is true with time dilation. You
00:31:31 --> 00:31:33 know you're you know that when you go
00:31:33 --> 00:31:36 nearer the speed of light, your clocks
00:31:36 --> 00:31:39 tick slower. Uh that's a scene by a
00:31:39 --> 00:31:41 stationary observer. Uh and so it's the
00:31:41 --> 00:31:43 same sort of thing. If you're on the
00:31:43 --> 00:31:44 spacecraft, your clock is ticking at the
00:31:44 --> 00:31:46 same rate as it ever was. But to a
00:31:46 --> 00:31:48 stationary observer, your clocks tick
00:31:48 --> 00:31:48 slower.
00:31:48 --> 00:31:50 >> And this has been proven with atomic
00:31:50 --> 00:31:51 clocks, hasn't it?
00:31:51 --> 00:31:53 >> It has. And indeed with mass as well.
00:31:53 --> 00:31:55 You can do this. You can see this sort
00:31:55 --> 00:31:59 of phenomenon with um uh with uh cosmic
00:31:59 --> 00:32:01 rays which travel very close to the
00:32:01 --> 00:32:02 speed of light. You can see their mass
00:32:02 --> 00:32:06 change. So, um, that's from the point of
00:32:06 --> 00:32:08 view of somebody who's, you know, not
00:32:08 --> 00:32:09 moving at the same speed. If you're
00:32:10 --> 00:32:11 moving at the same speed, you don't see
00:32:11 --> 00:32:13 any change at all.
00:32:13 --> 00:32:14 >> That's pretty boring.
00:32:14 --> 00:32:16 >> I mean, the more the more we discuss
00:32:16 --> 00:32:18 black holes and the number of questions
00:32:18 --> 00:32:21 we get about them, people are really
00:32:21 --> 00:32:25 quite captivated by the strangeness of
00:32:25 --> 00:32:27 them. I suppose they they throw up all
00:32:27 --> 00:32:29 these things that seem so alien to what
00:32:29 --> 00:32:32 we consider normal. Uh, and that's
00:32:32 --> 00:32:35 because we've only experienced uh what's
00:32:35 --> 00:32:37 happening on our planet any given time.
00:32:37 --> 00:32:40 So to to try and comprehend um enough
00:32:40 --> 00:32:44 gravity to warp time to slow things down
00:32:44 --> 00:32:46 to the observer and and increase mass
00:32:46 --> 00:32:50 just it's really whack.
00:32:50 --> 00:32:52 Sad on the brain. That's true. And you
00:32:52 --> 00:32:55 know, but uh look, John's question there
00:32:55 --> 00:32:57 is is a great question because it's it's
00:32:57 --> 00:33:00 not intuitively obvious what is
00:33:00 --> 00:33:03 happening uh in a situation like
00:33:03 --> 00:33:04 something traveling close to the speed
00:33:04 --> 00:33:07 of light and and so he's right to ask
00:33:07 --> 00:33:09 would that mass actually turn it into a
00:33:09 --> 00:33:11 black hole? Uh but the answer is no
00:33:11 --> 00:33:12 because of the reasons that I've
00:33:12 --> 00:33:14 outlined. But it's great great thinking.
00:33:14 --> 00:33:16 >> It is indeed. Thank you, John. Thanks
00:33:16 --> 00:33:18 for the question. Do appreciate it. Keep
00:33:18 --> 00:33:19 your questions coming in. We're trying
00:33:19 --> 00:33:22 to um run them down, but they it's it's
00:33:22 --> 00:33:25 it's an ever growing mass really.
00:33:25 --> 00:33:27 >> It's all right. Look, as you said
00:33:27 --> 00:33:29 earlier, Andrew, um all the space
00:33:29 --> 00:33:30 nutters are going to get together and
00:33:30 --> 00:33:32 sort them out for themselves and we'll
00:33:32 --> 00:33:34 be
00:33:34 --> 00:33:35 >> encourage actually if uh if people want
00:33:35 --> 00:33:39 to ask questions of the group and and
00:33:39 --> 00:33:41 discuss it, they Yeah, by all means. Um
00:33:41 --> 00:33:43 that that's part of the reason we set up
00:33:43 --> 00:33:45 the Space Nuts podcast group. So, um,
00:33:45 --> 00:33:48 it's a good opportunity to not only meet
00:33:48 --> 00:33:50 like-minded people who enjoy these these
00:33:50 --> 00:33:52 topics, but also to maybe come up with
00:33:52 --> 00:33:54 your own ideas on on what might be. And,
00:33:54 --> 00:33:56 you know, I'll keep an eye on it, and if
00:33:56 --> 00:33:57 something pops in there that we think is
00:33:57 --> 00:34:00 worthy of further discussion, we will
00:34:00 --> 00:34:03 certainly investigate that. Uh, thanks
00:34:03 --> 00:34:05 to everyone who um who who sent in their
00:34:05 --> 00:34:08 questions uh and contributed and joined
00:34:08 --> 00:34:10 the Space Nuts podcast group and Patreon
00:34:10 --> 00:34:11 and everything else. We really
00:34:11 --> 00:34:14 appreciate it. Uh but most of all we
00:34:14 --> 00:34:16 appreciate you Fred. Thank you so much.
00:34:16 --> 00:34:18 >> It's a pleasure. Thank you for having me
00:34:18 --> 00:34:19 as always.
00:34:19 --> 00:34:21 >> And we will catch you next week.
00:34:21 --> 00:34:24 Professor Fred Watson, uh astronomer at
00:34:24 --> 00:34:26 large. And from me, Andrew Dunley, thank
00:34:26 --> 00:34:28 you again and we'll catch you next time
00:34:28 --> 00:34:30 on another edition of Space Nuts.
00:34:30 --> 00:34:31 >> Space Nuts.
00:34:31 --> 00:34:33 >> You've been listening to the Space Nuts
00:34:34 --> 00:34:36 podcast
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