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Space Nuts: Vanishing Stars, White Holes, Earth’s Mass and Neutrinos
In this listener Q&A episode of Space Nuts , Andrew Dunkley and Professor Fred Watson tackle four cosmic questions that stretch from distant stars to the nature of space-time. They explain why a star billions of light-years away would still appear in our sky long after it had gone out, and why looking across the universe means looking back through time. Next, they consider whether white holes are the opposite of black holes, then investigate whether dark matter could affect our measurements of Earth’s mass and gravity. Finally, they explore how neutrinos interact with gravity, whether black holes can capture them, and why space-time itself is not something a black hole can consume. Join Andrew and Fred Watson Watson for big ideas, listener curiosity and the occasional detour into the value of the Earth in dollars.
Key topics
- How light-travel time means we see distant stars as they were in the past.
- White holes as theoretical solutions to relativity, and how they differ from black holes.
- Whether dark matter contributes to Earth’s measured gravity and mass.
- The mass of the Earth and how astronomers determine it.
- Neutrinos, gravity, black holes and whether space-time can be consumed.
Timestamps
00:00 - Introduction and listener questions
01:30 - If a distant star goes out, when would we see it happen?
06:30 - Looking back in time across the observable universe
10:00 - What are white holes, and are they the opposite of black holes?
15:30 - Could dark matter affect measurements of Earth’s gravity?
20:30 - How the mass of Earth is determined
23:30 - Do neutrinos interact with gravity, and can black holes capture them?
27:00 - Could a black hole feed on space-time itself?
30:00 - How to send questions to Space Nuts and closing remarks
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Episode link: https://play.headliner.app/episode/36122919?utm_source=youtube
00:00:00 --> 00:00:02 Hi there, thanks for joining us on a Q&A
00:00:02 --> 00:00:05 edition of Space Nuts and this is where
00:00:05 --> 00:00:07 we answer audience questions and we've
00:00:07 --> 00:00:09 got a whole bunch today. We're going to
00:00:09 --> 00:00:12 talk about the light of a distance star
00:00:12 --> 00:00:15 a star or the lack of and what happens
00:00:15 --> 00:00:17 when the star goes out and the light you
00:00:17 --> 00:00:19 know, where does it go? Do we see it? Do
00:00:19 --> 00:00:21 we not?
00:00:21 --> 00:00:23 We'll tell you all about that.
00:00:23 --> 00:00:26 Black holes versus white holes. That's
00:00:26 --> 00:00:27 an old chestnut that comes up from time
00:00:27 --> 00:00:28 to time.
00:00:29 --> 00:00:32 The massive the earth is
00:00:32 --> 00:00:34 something that somebody wants to know
00:00:34 --> 00:00:36 about and we talked about black holes
00:00:36 --> 00:00:38 and white holes. What about neutrinos
00:00:38 --> 00:00:40 versus black holes? We'll answer all of
00:00:40 --> 00:00:43 that or not on this episode of Space
00:00:43 --> 00:00:44 Nuts.
00:00:44 --> 00:00:49 15 seconds. Guidance is internal. 10 9
00:00:49 --> 00:00:50 ignition sequence start.
00:00:50 --> 00:00:51 Space Nuts.
00:00:51 --> 00:00:54 5 4 3 2
00:00:54 --> 00:00:56 1 2 3 4 5 5 4 3 2 1
00:00:56 --> 00:00:58 Space Nuts.
00:00:58 --> 00:01:00 It feels so nice to be able to do this.
00:01:01 --> 00:01:02 Here again to try and solve all of that
00:01:02 --> 00:01:04 is Professor Fred Watson astronomer at
00:01:04 --> 00:01:06 large. Hi Fred.
00:01:06 --> 00:01:09 Nice to see you again Andrew.
00:01:09 --> 00:01:09 Fred.
00:01:09 --> 00:01:11 Still at large as well.
00:01:11 --> 00:01:14 Yes. I'm less large. I just I've been
00:01:14 --> 00:01:16 losing weight lately which
00:01:16 --> 00:01:18 isn't a bad thing. Isn't a bad thing.
00:01:18 --> 00:01:19 Okay.
00:01:19 --> 00:01:21 I'm back to manageable levels.
00:01:21 --> 00:01:23 Well, that's good. Well, congratulations
00:01:23 --> 00:01:23 on that.
00:01:23 --> 00:01:25 Thank you. Yeah, I think it's the first
00:01:25 --> 00:01:27 time in a decade I've been under 80
00:01:27 --> 00:01:29 kilos.
00:01:29 --> 00:01:31 Oh, that's
00:01:31 --> 00:01:32 that's quite light.
00:01:32 --> 00:01:32 Yeah.
00:01:32 --> 00:01:34 For somebody of your height.
00:01:34 --> 00:01:37 It's about right for my height.
00:01:37 --> 00:01:38 Okay.
00:01:38 --> 00:01:39 But
00:01:39 --> 00:01:43 yeah, it's taken a while but by design
00:01:43 --> 00:01:45 slow and steady is the way to do it.
00:01:45 --> 00:01:46 That's a great thing.
00:01:46 --> 00:01:47 I took my sweet time about it. That's
00:01:47 --> 00:01:50 for sure.
00:01:50 --> 00:01:52 All right. We've got some questions to
00:01:52 --> 00:01:54 deal with. Do you want to hear the first
00:01:54 --> 00:01:55 one?
00:01:55 --> 00:01:58 I could I could say let me guess but um
00:01:59 --> 00:02:00 might hear it instead.
00:02:00 --> 00:02:02 This comes from Billy.
00:02:02 --> 00:02:05 Professor Watson, Andrew, Billy Gerard
00:02:05 --> 00:02:08 here in New Jersey on the great old big
00:02:08 --> 00:02:11 old USA. I I got a quick question. Let's
00:02:11 --> 00:02:13 just say hypothetically we are looking
00:02:13 --> 00:02:16 at a star that's a billion light-years
00:02:16 --> 00:02:18 away. And we're So so theoretically
00:02:18 --> 00:02:20 we're looking back in time a billion
00:02:20 --> 00:02:21 years. Now, hypothetically let's just
00:02:21 --> 00:02:25 say that one day that star just goes
00:02:25 --> 00:02:28 out. It stops shining.
00:02:28 --> 00:02:31 Like would we still see that star for
00:02:31 --> 00:02:32 like would like does that light that's
00:02:32 --> 00:02:35 on its way to us keep coming? Like would
00:02:35 --> 00:02:37 it take a billion years before we saw it
00:02:37 --> 00:02:39 go out? How does that work? Help me
00:02:39 --> 00:02:41 understand that. Finally love you guys
00:02:41 --> 00:02:43 love you both love the podcast love
00:02:43 --> 00:02:45 hearing you and uh
00:02:45 --> 00:02:46 like boy I go all the way I've been
00:02:46 --> 00:02:48 listening to you guys for a really long
00:02:48 --> 00:02:50 time. So I really appreciate the podcast
00:02:50 --> 00:02:51 and everything you do. And thanks so
00:02:51 --> 00:02:54 much for taking the call. Billy Gerard
00:02:54 --> 00:02:59 here in uh New Jersey US of A.
00:02:59 --> 00:03:01 Thank you, Billy. Uh so lovely to hear
00:03:01 --> 00:03:02 from you and I'm glad you've been a
00:03:02 --> 00:03:04 long-term listener and uh
00:03:04 --> 00:03:06 glad you finally got through to us with
00:03:06 --> 00:03:07 a question.
00:03:07 --> 00:03:09 Uh this this sort of
00:03:09 --> 00:03:10 uh is the same or similar to the
00:03:10 --> 00:03:13 question that we had recently the
00:03:13 --> 00:03:15 hypothetical about the sun suddenly
00:03:15 --> 00:03:17 switching off and how much light we
00:03:17 --> 00:03:20 would see. Like if if it switched off
00:03:20 --> 00:03:22 right now
00:03:22 --> 00:03:24 we wouldn't see that happen for another
00:03:24 --> 00:03:26 8 and a bit minutes 8 minutes 20 seconds
00:03:26 --> 00:03:27 or something to that effect.
00:03:27 --> 00:03:28 Exactly.
00:03:28 --> 00:03:30 It's the same for stars all over the
00:03:30 --> 00:03:32 universe, is it not?
00:03:32 --> 00:03:33 Yes, it is.
00:03:33 --> 00:03:34 Except that it'll be longer than 8
00:03:34 --> 00:03:35 minutes and 20 seconds.
00:03:35 --> 00:03:37 That's That's right. So it's the same
00:03:37 --> 00:03:40 principle that light
00:03:40 --> 00:03:43 travels at that rapid speed of 300
00:03:43 --> 00:03:44 km
00:03:44 --> 00:03:49 per second or in units that um anybody
00:03:49 --> 00:03:51 in the USA will understand, 1 ft in a
00:03:51 --> 00:03:53 billionth of a second.
00:03:53 --> 00:03:53 Ooh.
00:03:53 --> 00:03:55 Uh
00:03:55 --> 00:03:57 So yeah, that's quite convenient
00:03:57 --> 00:03:59 actually that it's a foot in a billionth
00:03:59 --> 00:04:00 of a second.
00:04:00 --> 00:04:04 Um So yes, so that's the exactly how it
00:04:04 --> 00:04:06 works. I mean, there's a there's always
00:04:06 --> 00:04:11 the analog of um, you know, sound. We We
00:04:11 --> 00:04:15 when we listen to something a a noise
00:04:15 --> 00:04:16 made by something at a distance, for
00:04:16 --> 00:04:18 example, uh, lightning. And there was
00:04:18 --> 00:04:19 plenty of lightning around here last
00:04:19 --> 00:04:20 night. We had a
00:04:20 --> 00:04:22 Huge storm last night. I've seen some of
00:04:22 --> 00:04:23 the footage. Woo.
00:04:23 --> 00:04:24 Yeah.
00:04:24 --> 00:04:26 Uh, you get a flash, um, and then it
00:04:26 --> 00:04:28 takes
00:04:28 --> 00:04:30 well, it takes sometimes minutes several
00:04:30 --> 00:04:32 minutes for the uh, sorry, several
00:04:32 --> 00:04:35 seconds for the sound to reach you. Um,
00:04:35 --> 00:04:37 and so, if you you know, if the only way
00:04:37 --> 00:04:39 you knew about this thing was by the
00:04:39 --> 00:04:41 sound uh, you'd you'd be listening in
00:04:41 --> 00:04:43 the past, as it were, because of that
00:04:43 --> 00:04:46 several seconds that it took. Uh, and
00:04:46 --> 00:04:48 it's true with uh, stars, whether they
00:04:48 --> 00:04:49 are
00:04:49 --> 00:04:51 as near as the sun is, and you're
00:04:51 --> 00:04:53 exactly right, 8 minutes and 20 seconds
00:04:53 --> 00:04:55 is the light time from the sun to the
00:04:55 --> 00:04:57 Earth. We wouldn't know anything about
00:04:57 --> 00:05:00 it until 8 minutes and 20 seconds had
00:05:00 --> 00:05:02 gone by after the sun had managed to
00:05:02 --> 00:05:04 disappear or become
00:05:04 --> 00:05:07 extinct or what whatever. Um, and as
00:05:07 --> 00:05:09 we've spoken about before, gravity
00:05:09 --> 00:05:10 actually would work the same way,
00:05:10 --> 00:05:11 because gravity
00:05:11 --> 00:05:14 uh, also our gravitational waves also
00:05:14 --> 00:05:15 travel at the speed of light.
00:05:15 --> 00:05:15 Mhm.
00:05:15 --> 00:05:16 Or
00:05:16 --> 00:05:18 the impulse of gravity. So, yeah, it's
00:05:18 --> 00:05:20 uh, it's absolutely right, Billy. You're
00:05:20 --> 00:05:22 looking back in time, and you're looking
00:05:22 --> 00:05:24 back in time sometimes a long, long way.
00:05:24 --> 00:05:25 Um,
00:05:25 --> 00:05:26 certainly
00:05:26 --> 00:05:28 the uh, um, you know, the most distant
00:05:28 --> 00:05:31 things that we can see we're seeing as
00:05:31 --> 00:05:32 them as they were when the universe was
00:05:32 --> 00:05:34 only about 300 million years old. So,
00:05:34 --> 00:05:36 you're looking back almost the whole
00:05:36 --> 00:05:38 13.8 billion year history of the
00:05:38 --> 00:05:41 universe, which is staggering, really.
00:05:41 --> 00:05:44 It is. Uh, and just for the record, uh,
00:05:44 --> 00:05:47 the furthest star ever detected at this
00:05:47 --> 00:05:52 point in time is 12.9 billion
00:05:52 --> 00:05:53 light years from Earth.
00:05:53 --> 00:05:55 That's right. So, um,
00:05:55 --> 00:05:57 um, that means, you know, it emitted its
00:05:57 --> 00:06:00 light when the universe was 900 million
00:06:00 --> 00:06:03 years old. Um, and I do remember reading
00:06:03 --> 00:06:06 about that uh, some time ago. We We
00:06:06 --> 00:06:07 probably covered it on Space Nuts. But
00:06:07 --> 00:06:09 and the only reason we could see a
00:06:09 --> 00:06:11 single star is because it's
00:06:11 --> 00:06:13 gravitationally lensed. It's being
00:06:13 --> 00:06:16 magnified by the gravitational
00:06:16 --> 00:06:18 distortion of of a cluster of galaxies
00:06:18 --> 00:06:19 in front of it. So, we can't see an
00:06:19 --> 00:06:21 individual star at that distance.
00:06:21 --> 00:06:23 Yes, we can. But
00:06:23 --> 00:06:25 I don't I can't remember what the number
00:06:25 --> 00:06:27 Billy said was 10 billion or
00:06:27 --> 00:06:28 1 billion.
00:06:28 --> 00:06:30 Uh yeah, I think he said 10 billion.
00:06:30 --> 00:06:32 Yeah, so sorry. No, he said a billion.
00:06:32 --> 00:06:32 So,
00:06:32 --> 00:06:35 if a star a billion light years away,
00:06:35 --> 00:06:38 Billy, just suddenly went out right now,
00:06:38 --> 00:06:41 you'd have to set your watch
00:06:41 --> 00:06:44 to go off in a billion years,
00:06:44 --> 00:06:46 basically. Give or take because of
00:06:46 --> 00:06:48 gravitational lensing and other other
00:06:48 --> 00:06:49 effects.
00:06:49 --> 00:06:51 Um but it would take that long for you
00:06:51 --> 00:06:53 to see it go out.
00:06:53 --> 00:06:55 It's It's just hard to get your head
00:06:55 --> 00:06:58 around that sometimes, isn't it? Um that
00:06:58 --> 00:07:00 that everything's finite, even light. I
00:07:00 --> 00:07:01 mean, it's Yeah.
00:07:01 --> 00:07:03 There's a limit.
00:07:03 --> 00:07:04 I think what's
00:07:04 --> 00:07:06 what's more almost more profound is that
00:07:06 --> 00:07:09 um our view of the universe
00:07:09 --> 00:07:10 doesn't matter whether you're talking
00:07:10 --> 00:07:12 about individual stars
00:07:12 --> 00:07:15 or galaxies or nebulae or whatever, we
00:07:15 --> 00:07:18 are always looking into the past. So,
00:07:18 --> 00:07:20 hm, you know, when we look outwards,
00:07:20 --> 00:07:22 we're just looking further and further
00:07:22 --> 00:07:23 and further back in time. It's why we
00:07:23 --> 00:07:26 talk about space-time because space and
00:07:26 --> 00:07:30 time are so intimately related. Um and
00:07:30 --> 00:07:32 that means
00:07:32 --> 00:07:34 because gravity also works on that speed
00:07:34 --> 00:07:37 limit, um
00:07:37 --> 00:07:38 there's no point in really thinking
00:07:38 --> 00:07:40 about things
00:07:40 --> 00:07:42 in what we might think of as an absolute
00:07:42 --> 00:07:44 sense where you're looking at the
00:07:44 --> 00:07:45 universe from outside and seeing
00:07:45 --> 00:07:47 everything in it happening, uh
00:07:47 --> 00:07:50 you know, simultaneously, almost. Um
00:07:50 --> 00:07:52 it's always
00:07:52 --> 00:07:54 um modified by our view, the fact that
00:07:54 --> 00:07:57 we are at the center of a an observing
00:07:57 --> 00:08:00 sphere. It's a we're only a an imaginary
00:08:00 --> 00:08:01 point, and you know, there's nothing
00:08:01 --> 00:08:04 significant about where we are. But it
00:08:04 --> 00:08:07 means that our whole a of observation
00:08:07 --> 00:08:10 it this time gradient across it, going
00:08:10 --> 00:08:12 back right to the Big Bang itself, cuz
00:08:12 --> 00:08:13 we can still see the flash of the Big
00:08:13 --> 00:08:15 Bang in the cosmic radiation.
00:08:15 --> 00:08:16 Cosmic background radiation.
00:08:16 --> 00:08:18 It's incredible. Uh
00:08:18 --> 00:08:21 I was reading an article
00:08:21 --> 00:08:24 uh on the weekend uh about a scientist
00:08:24 --> 00:08:25 who was
00:08:25 --> 00:08:27 um quite prominent in the past. I can't
00:08:27 --> 00:08:29 think of his name right now, but, uh, he
00:08:29 --> 00:08:31 kind of got debunked
00:08:31 --> 00:08:32 or criticized or laughed at, whatever
00:08:32 --> 00:08:34 you like, for coming up with the theory
00:08:34 --> 00:08:38 that our existence is based purely on
00:08:38 --> 00:08:40 consciousness; that the universe and
00:08:40 --> 00:08:42 everything that's happening in it exists
00:08:42 --> 00:08:45 because we are
00:08:45 --> 00:08:47 sentient beings; that we are, we are
00:08:47 --> 00:08:49 creating all of this.
00:08:49 --> 00:08:52 Um it is so hard to
00:08:52 --> 00:08:53 I think that's going on in your head.
00:08:53 --> 00:08:56 I think that's the strong anthropic
00:08:56 --> 00:08:57 principle, I think.
00:08:57 --> 00:08:59 That's that's exactly what it was, yes.
00:08:59 --> 00:08:59 Yeah.
00:08:59 --> 00:09:01 Um I can't remember why it came up. It
00:09:01 --> 00:09:04 was probably just one of those newsfeeds
00:09:04 --> 00:09:06 that pops up from time to time, but uh
00:09:06 --> 00:09:06 yeah.
00:09:06 --> 00:09:08 Yeah, it's a fascinating theory.
00:09:08 --> 00:09:09 Um
00:09:09 --> 00:09:11 but there are those who believe you can
00:09:11 --> 00:09:13 manipulate that to your advantage, but I
00:09:13 --> 00:09:16 don't know if that's true or not. Um
00:09:16 --> 00:09:18 there was a famous case of a woman who
00:09:18 --> 00:09:19 um
00:09:19 --> 00:09:21 claimed that she could, and she won
00:09:21 --> 00:09:24 more prizes than anyone in history or
00:09:24 --> 00:09:26 something like that.
00:09:26 --> 00:09:27 There's some strange stories out there.
00:09:27 --> 00:09:28 Could just be coincidence, that's
00:09:28 --> 00:09:30 another theory as well.
00:09:30 --> 00:09:32 Thank you, Billy. Uh awesome to hear
00:09:32 --> 00:09:35 from you in the lovely state of New
00:09:35 --> 00:09:36 Jersey.
00:09:36 --> 00:09:38 Uh our next question on SpaceNuts Fred
00:09:38 --> 00:09:40 comes from
00:09:40 --> 00:09:42 uh Tristan and Simon. Simon's the dad,
00:09:42 --> 00:09:44 Tristan's his son. My 9-year-old son
00:09:44 --> 00:09:46 Tristan, see, I was right.
00:09:46 --> 00:09:49 Uh and I
00:09:49 --> 00:09:51 My 9-year-old son Tristan and I listen
00:09:51 --> 00:09:54 to your podcast on our daily drive to
00:09:54 --> 00:09:56 school, and he has a question among
00:09:56 --> 00:09:58 many. Tristan is interested in black
00:09:58 --> 00:10:01 holes and has heard about the
00:10:01 --> 00:10:04 theoretical idea of a white hole. His
00:10:04 --> 00:10:06 question is, if black holes have
00:10:06 --> 00:10:08 extremely high gravity, are white holes
00:10:08 --> 00:10:11 the opposite? Thank you for keeping us
00:10:11 --> 00:10:14 entertained and curious during our long
00:10:14 --> 00:10:17 commute, Tristan and Simon.
00:10:17 --> 00:10:19 Thanks uh to both of you and uh hello
00:10:19 --> 00:10:22 Tristan. Hope uh all is well at school.
00:10:22 --> 00:10:23 I don't know if you like school or
00:10:23 --> 00:10:27 loathe it. Uh I was not
00:10:27 --> 00:10:30 a very motivated student when I went to
00:10:30 --> 00:10:31 school. I think I did most of my
00:10:31 --> 00:10:34 learning when I got out.
00:10:34 --> 00:10:36 Um after they unlocked the doors. But
00:10:36 --> 00:10:38 anyway, um
00:10:38 --> 00:10:40 Tristan's got a good question. We've had
00:10:40 --> 00:10:41 black hole, white hole questions a few
00:10:41 --> 00:10:44 times in the past uh and
00:10:44 --> 00:10:48 it is probably logical to say that the
00:10:48 --> 00:10:50 theory is it would be quite the
00:10:50 --> 00:10:52 opposite. That that's the reason it's
00:10:52 --> 00:10:55 called a white hole, I think. Or it they
00:10:55 --> 00:10:58 think it's white. I don't know, Fred.
00:10:58 --> 00:10:59 We haven't found one yet.
00:10:59 --> 00:11:02 No, we haven't. Uh so they are
00:11:02 --> 00:11:04 theoretical entity.
00:11:04 --> 00:11:05 Uh
00:11:05 --> 00:11:08 and they are mathematically the opposite
00:11:08 --> 00:11:10 of a black hole
00:11:10 --> 00:11:16 uh in terms of some of the aspects.
00:11:16 --> 00:11:17 Particularly in terms of something
00:11:17 --> 00:11:20 called time reversal. Uh
00:11:20 --> 00:11:22 a comment that I've seen is if you
00:11:22 --> 00:11:23 played a video of a black hole
00:11:23 --> 00:11:25 backwards, it would look like a white
00:11:25 --> 00:11:26 hole.
00:11:26 --> 00:11:28 Um
00:11:28 --> 00:11:29 that
00:11:29 --> 00:11:30 we
00:11:30 --> 00:11:33 Yeah, we we don't To be honest, most
00:11:33 --> 00:11:34 physicists don't believe that they
00:11:34 --> 00:11:36 exist.
00:11:36 --> 00:11:36 Uh
00:11:36 --> 00:11:39 that um they're not real. But
00:11:39 --> 00:11:41 just going to the question that Tristan
00:11:41 --> 00:11:43 has posed, um black holes have extremely
00:11:43 --> 00:11:46 high gravity. Uh white hole's the
00:11:46 --> 00:11:49 opposite. Uh and the answer is it No,
00:11:49 --> 00:11:52 they're not. They still have a gra-
00:11:52 --> 00:11:55 They still have a gravitational field
00:11:55 --> 00:11:57 because they've got mass.
00:11:57 --> 00:11:58 Uh
00:11:58 --> 00:12:00 it's You know, that doesn't go in The
00:12:00 --> 00:12:02 time reversal doesn't affect that.
00:12:02 --> 00:12:04 But so what the the main thing is it
00:12:04 --> 00:12:06 doesn't have negative gravity, which is
00:12:06 --> 00:12:08 what you might think cuz it's the
00:12:08 --> 00:12:09 opposite of a black hole in every other
00:12:09 --> 00:12:12 way. But it's not the
00:12:12 --> 00:12:15 not the fact that its mass becomes
00:12:15 --> 00:12:16 negative,
00:12:16 --> 00:12:20 it's the way space-time behaves behaves
00:12:20 --> 00:12:21 around it.
00:12:21 --> 00:12:24 Um that's the crucial thing that makes
00:12:24 --> 00:12:25 it
00:12:25 --> 00:12:27 uh a white hole where it's trying to
00:12:27 --> 00:12:29 push everything outwards rather than
00:12:29 --> 00:12:31 pull everything inwards, which is what a
00:12:31 --> 00:12:33 black hole is doing. So, it's all is a
00:12:33 --> 00:12:35 geometrical point. And I And I should
00:12:35 --> 00:12:37 just highlight here that the whole of
00:12:37 --> 00:12:40 relativity is built on geometry. Uh it's
00:12:40 --> 00:12:43 a geo geometrical theory. Um
00:12:43 --> 00:12:45 I'd um I did a talk on it a couple of
00:12:45 --> 00:12:46 weeks ago, and I actually took the
00:12:46 --> 00:12:48 equations out of it just because I
00:12:48 --> 00:12:50 didn't want to bore everybody to death.
00:12:50 --> 00:12:51 But, the equations of relativity are
00:12:51 --> 00:12:54 basically geometry. Uh in fact, in a
00:12:54 --> 00:12:56 sense, it's all Pythagoras'theorem, but
00:12:56 --> 00:12:58 it's very highly modified.
00:12:58 --> 00:13:00 Um and so, the geometry of the
00:13:00 --> 00:13:01 space-time around the white hole is what
00:13:01 --> 00:13:04 makes everything want to get pushed out
00:13:04 --> 00:13:08 rather than it having negative mass.
00:13:08 --> 00:13:11 Okay. Yes, I understand. Um
00:13:11 --> 00:13:14 I'm just I was just doing an AI search
00:13:14 --> 00:13:16 on that very thing, and it says white
00:13:16 --> 00:13:17 holes are mathematically possible under
00:13:17 --> 00:13:19 Einstein's general theory of relativity,
00:13:19 --> 00:13:21 but physically
00:13:21 --> 00:13:23 unproven and unlikely to exist in our
00:13:23 --> 00:13:25 universe.
00:13:25 --> 00:13:26 I think I said something very similar to
00:13:26 --> 00:13:27 that.
00:13:27 --> 00:13:29 Yeah.
00:13:29 --> 00:13:30 You know, I just wanted to compete with
00:13:30 --> 00:13:31 Einstein.
00:13:31 --> 00:13:33 Me and AI were like that.
00:13:33 --> 00:13:34 Yeah.
00:13:34 --> 00:13:36 Yeah, it's got its positives, but it's
00:13:36 --> 00:13:38 certainly getting some bad press, too.
00:13:38 --> 00:13:40 Yeah, it is. Yes, it is indeed.
00:13:40 --> 00:13:42 Uh I I learned a new um online word.
00:13:42 --> 00:13:45 It's not a new word, but it's a new
00:13:45 --> 00:13:48 use for the word. It's It's called slop.
00:13:48 --> 00:13:50 Do you know what slop means?
00:13:50 --> 00:13:54 Um it's Yes, it is the the sort of
00:13:54 --> 00:13:56 it's AI that's not got things quite
00:13:56 --> 00:13:57 right. Is that right?
00:13:57 --> 00:14:00 It's sort of It's It's where an entire
00:14:00 --> 00:14:04 paper, book, article, whatever, has been
00:14:04 --> 00:14:07 AI generated. Absolutely no human
00:14:07 --> 00:14:09 creation in it at all.
00:14:09 --> 00:14:11 And unfortunately, it's starting to
00:14:11 --> 00:14:13 happen more and more and more.
00:14:13 --> 00:14:13 Yeah.
00:14:13 --> 00:14:16 It's nasty stuff. Uh and white holes are
00:14:16 --> 00:14:19 slop as well. Now, we don't know that.
00:14:19 --> 00:14:19 Um
00:14:19 --> 00:14:21 but
00:14:21 --> 00:14:24 we do know if black holes exist. We
00:14:24 --> 00:14:26 don't know if black white holes exist.
00:14:26 --> 00:14:28 They probably don't, but uh they would
00:14:28 --> 00:14:31 not be the exact opposite of a black
00:14:31 --> 00:14:32 hole is what we're saying.
00:14:32 --> 00:14:33 Yeah, that's right. In the in that
00:14:33 --> 00:14:35 regard, it's um it's what they do to
00:14:35 --> 00:14:38 space-time that changes the basically
00:14:38 --> 00:14:39 changes the um
00:14:39 --> 00:14:41 the the nature of the thing into
00:14:41 --> 00:14:43 something that's the opposite of a white
00:14:43 --> 00:14:44 of a black hole.
00:14:44 --> 00:14:44 Mhm.
00:14:44 --> 00:14:47 A great question, Tristan, and one I'm
00:14:47 --> 00:14:50 absolutely delighted you um you asked
00:14:50 --> 00:14:52 because it gave me a chance to think all
00:14:52 --> 00:14:54 that stuff through and bring back some
00:14:54 --> 00:14:55 memories of what I learned a few years
00:14:55 --> 00:14:56 ago.
00:14:56 --> 00:14:59 Very good. Uh thanks, Tristan. Thanks,
00:14:59 --> 00:15:01 Simon. And uh keep the curiosity coming.
00:15:01 --> 00:15:04 We love hearing from uh the younger
00:15:04 --> 00:15:06 audience members here on Space Nuts.
00:15:06 --> 00:15:08 You're with Andrew Dunkley and Professor
00:15:08 --> 00:15:11 Fred Watson.
00:15:11 --> 00:15:13 Let's take a quick break from the show
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00:16:44 --> 00:16:49 out more. That's nordvpn.com/spacenuts.
00:16:49 --> 00:16:50 And don't forget the code word Space
00:16:50 --> 00:16:51 Nuts.
00:16:51 --> 00:16:53 I believe that this nation should commit
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00:16:54 --> 00:16:56 to achieving the goal
00:16:56 --> 00:16:59 before this decade is out of landing a
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00:17:01 --> 00:17:02 to the earth.
00:17:02 --> 00:17:04 Space Nuts.
00:17:04 --> 00:17:08 Our next question, Fred, is massive.
00:17:08 --> 00:17:10 Hey, Space Nuts. This is Mike in
00:17:10 --> 00:17:12 Hayward, California.
00:17:12 --> 00:17:14 Got a question for you about dark
00:17:14 --> 00:17:16 matter, big surprise.
00:17:16 --> 00:17:18 So, I've been thinking about dark
00:17:18 --> 00:17:20 matter, and the way that you've
00:17:20 --> 00:17:23 described it on the podcast
00:17:23 --> 00:17:26 is, it seems to be the solution to the
00:17:26 --> 00:17:28 problem that astronomers observe when
00:17:28 --> 00:17:30 they look at galaxies
00:17:30 --> 00:17:32 and they see the rate at which they're
00:17:32 --> 00:17:33 spinning
00:17:33 --> 00:17:37 doesn't quite line up with the mass that
00:17:37 --> 00:17:39 they can calculate of the galaxy. That
00:17:39 --> 00:17:42 it seems like the stars should be flying
00:17:42 --> 00:17:44 off into space
00:17:44 --> 00:17:46 except that they're not. So, there must
00:17:46 --> 00:17:49 be more matter there that is causing a
00:17:49 --> 00:17:53 gravitational force to keep them in
00:17:53 --> 00:17:54 place.
00:17:54 --> 00:17:57 So, I've been thinking about
00:17:57 --> 00:17:59 are there other ways to measure this
00:17:59 --> 00:18:01 more locally?
00:18:01 --> 00:18:03 And I was thinking about the earth
00:18:03 --> 00:18:06 and we can make a direct accurate
00:18:06 --> 00:18:08 measurement of the earth's gravity
00:18:08 --> 00:18:09 but we can't really make a direct
00:18:09 --> 00:18:13 measurement of the earth's mass. So, my
00:18:13 --> 00:18:17 question is is the earth's mass over
00:18:17 --> 00:18:19 overestimated because there's a
00:18:19 --> 00:18:22 component of the gravity that we feel
00:18:22 --> 00:18:25 that is attributable to dark matter and
00:18:25 --> 00:18:28 not all of it is baryonic matter.
00:18:28 --> 00:18:30 Anyway, hope that makes sense. Love your
00:18:30 --> 00:18:32 podcast. Can't wait to hear the answer.
00:18:32 --> 00:18:34 Thanks, guys.
00:18:34 --> 00:18:35 Thank you, Mike. Oh, you put a lot of
00:18:35 --> 00:18:38 thought into that. That's That's um
00:18:38 --> 00:18:39 That's
00:18:39 --> 00:18:40 uh um
00:18:40 --> 00:18:42 It's a difficult question to get your
00:18:42 --> 00:18:43 head around.
00:18:43 --> 00:18:44 Um
00:18:44 --> 00:18:47 So, over to you, Fred.
00:18:47 --> 00:18:48 I was going to get on to I was going to
00:18:48 --> 00:18:50 paraphrase what he was asking, but it's
00:18:50 --> 00:18:51 just gone straight in one ear out the
00:18:51 --> 00:18:53 other.
00:18:53 --> 00:18:54 So, yes.
00:18:54 --> 00:18:56 I'm so
00:18:56 --> 00:18:56 uh
00:18:56 --> 00:19:00 Well, um Mike's point was that we can
00:19:00 --> 00:19:02 measure
00:19:02 --> 00:19:05 gravity on Earth more accurately
00:19:05 --> 00:19:06 accurately that we can than we can
00:19:06 --> 00:19:08 measure its mass.
00:19:08 --> 00:19:10 Um I don't think that's true. The mass
00:19:10 --> 00:19:13 of the Earth is very well determined and
00:19:13 --> 00:19:14 it comes actually from space
00:19:14 --> 00:19:16 observations. You can
00:19:16 --> 00:19:18 just looking at the dynamics of the
00:19:18 --> 00:19:20 solar system, the way the planet moves
00:19:20 --> 00:19:22 in its orbit around the Sun, and the way
00:19:22 --> 00:19:24 it interacts with the other planets, we
00:19:24 --> 00:19:27 know its mass to a very high accuracy.
00:19:27 --> 00:19:29 Um and so
00:19:29 --> 00:19:31 that's
00:19:31 --> 00:19:34 not something we can compare
00:19:34 --> 00:19:36 and so so
00:19:36 --> 00:19:37 we know its mass
00:19:37 --> 00:19:39 the gravitational pull
00:19:39 --> 00:19:41 as a result of that, which we can also
00:19:41 --> 00:19:42 measure
00:19:42 --> 00:19:45 uh is completely consistent with its
00:19:45 --> 00:19:46 mass. So,
00:19:46 --> 00:19:48 um I think what Mike is asking is if you
00:19:48 --> 00:19:50 measure the mass of the Earth and you
00:19:50 --> 00:19:52 measure its gravitational pull
00:19:52 --> 00:19:55 uh is there a a component of that
00:19:55 --> 00:19:57 gravitational pull that's not due to the
00:19:57 --> 00:19:59 Earth, it's due to dark matter?
00:19:59 --> 00:20:03 And the answer is no because
00:20:03 --> 00:20:07 we on Earth are immersed in a blob of
00:20:07 --> 00:20:08 dark matter, which certainly has
00:20:08 --> 00:20:11 gravitational pull, but it's it's going
00:20:11 --> 00:20:14 in all directions, and so we don't feel
00:20:14 --> 00:20:17 its effects. It We don't
00:20:17 --> 00:20:19 It just cancels out. It's It's pulling
00:20:19 --> 00:20:21 in all directions because blobs of dark
00:20:21 --> 00:20:22 matter.
00:20:22 --> 00:20:26 Uh
00:20:26 --> 00:20:27 Um
00:20:27 --> 00:20:29 Did Did you hear that?
00:20:29 --> 00:20:31 That sounds like a dark matter.
00:20:31 --> 00:20:33 It was It was um
00:20:33 --> 00:20:35 It was me uh tripping over a cable
00:20:35 --> 00:20:38 underneath my desk, which pulled all
00:20:38 --> 00:20:41 this stuff attached to it down onto the
00:20:41 --> 00:20:41 Oh.
00:20:41 --> 00:20:43 onto the floor.
00:20:43 --> 00:20:44 I can still see you. That's the good
00:20:44 --> 00:20:46 news and I can still hear you.
00:20:46 --> 00:20:48 Yeah, no, it's all right. It's not done
00:20:48 --> 00:20:51 any harm. My table lamp is lying
00:20:51 --> 00:20:53 pointing awkwardly upwards rather than
00:20:53 --> 00:20:55 downwards like it's supposed to be, but
00:20:55 --> 00:20:57 everything will be fine.
00:20:57 --> 00:20:59 I'm not really worried about that.
00:20:59 --> 00:21:03 Um So, um yeah, so so dark matter
00:21:03 --> 00:21:06 basically what you can you can you know,
00:21:06 --> 00:21:07 if you imagine the Earth, there it is
00:21:07 --> 00:21:10 trundling around in its orbit, but it's
00:21:10 --> 00:21:13 it's immersed in a blob of dark matter,
00:21:13 --> 00:21:15 which is probably much bigger than the
00:21:15 --> 00:21:19 whole galaxy. And so, the that the
00:21:19 --> 00:21:20 density of that dark matter is
00:21:20 --> 00:21:23 effectively the same everywhere as far
00:21:23 --> 00:21:24 as the Earth's concerned.
00:21:24 --> 00:21:24 Right.
00:21:24 --> 00:21:26 And so, it's pulling in all directions.
00:21:26 --> 00:21:28 You You can just take it completely out
00:21:28 --> 00:21:30 of the the equations of motions of a
00:21:30 --> 00:21:32 planet.
00:21:32 --> 00:21:34 Okay, so would would the dark matter be
00:21:34 --> 00:21:37 moving with the Earth and with the
00:21:37 --> 00:21:40 galaxy or are we passing through it?
00:21:40 --> 00:21:42 Uh it's it's probably um there probably
00:21:42 --> 00:21:45 isn't a relative velocity between us and
00:21:45 --> 00:21:47 dark matter. Although, there is an
00:21:47 --> 00:21:50 experiment that's being done in Gran
00:21:50 --> 00:21:53 Sasso, in Italy, that suggests that we
00:21:53 --> 00:21:55 are moving through dark matter because
00:21:55 --> 00:21:57 they think they see a different
00:21:57 --> 00:22:00 signature of certain I think it's gamma
00:22:00 --> 00:22:02 radiation that they're picking up, uh,
00:22:02 --> 00:22:04 when the Earth is on one side of its
00:22:04 --> 00:22:06 orbit from when it's on the other side.
00:22:06 --> 00:22:09 Uh but more or less, you can imagine
00:22:09 --> 00:22:11 that the blob of dark matter is rotating
00:22:11 --> 00:22:14 with the galaxy. That's very roughly.
00:22:14 --> 00:22:17 Okay. So, what was the answer to Mike's
00:22:17 --> 00:22:18 question?
00:22:18 --> 00:22:19 No.
00:22:19 --> 00:22:21 No?
00:22:21 --> 00:22:23 I love it when it's that simple.
00:22:23 --> 00:22:25 Yeah, I can't remember what the question
00:22:25 --> 00:22:27 was. Let me just have a quick look to
00:22:27 --> 00:22:29 remind me.
00:22:29 --> 00:22:31 Actually, no. It's It's an audio
00:22:31 --> 00:22:34 question, so I can't see it.
00:22:34 --> 00:22:37 But yes, the the
00:22:37 --> 00:22:40 I like the idea of, you know, taking
00:22:40 --> 00:22:42 measuring the Earth's gravity, measuring
00:22:42 --> 00:22:44 its mass, and
00:22:44 --> 00:22:46 from its mass you work out how much
00:22:46 --> 00:22:47 gravity it should have, and then you
00:22:47 --> 00:22:50 compare the two, the measurement of the
00:22:50 --> 00:22:52 gravity with the theoretical prediction.
00:22:52 --> 00:22:54 But they're exactly the same, and that's
00:22:54 --> 00:22:56 because the dark matter's gravity
00:22:56 --> 00:22:57 cancels out, basically.
00:22:57 --> 00:22:59 Oh, here's a test for you, Fred.
00:22:59 --> 00:23:02 What is the mass of the Earth?
00:23:02 --> 00:23:04 Um it's about
00:23:04 --> 00:23:06 a few tons, isn't it? It's um
00:23:06 --> 00:23:07 It's a couple of kilograms.
00:23:07 --> 00:23:11 Yeah, the number I think the Sun's mass
00:23:11 --> 00:23:12 is
00:23:12 --> 00:23:15 10 to 27
00:23:15 --> 00:23:17 kilograms. Is that right, or is that
00:23:17 --> 00:23:19 tons? I can't remember. But it's a
00:23:19 --> 00:23:22 number with a lot of zeros after it.
00:23:22 --> 00:23:23 What is the mass of the
00:23:23 --> 00:23:24 tons.
00:23:24 --> 00:23:29 52*10 to the 24th kilograms, or
00:23:29 --> 00:23:33 5 trillion kilograms.
00:23:33 --> 00:23:33 Yep.
00:23:33 --> 00:23:34 I don't know what that is in pounds.
00:23:34 --> 00:23:36 Sorry, America.
00:23:36 --> 00:23:38 I apologize.
00:23:38 --> 00:23:40 Yeah, what is it in dollars? That's the
00:23:40 --> 00:23:40 thing.
00:23:40 --> 00:23:42 That's a good question.
00:23:42 --> 00:23:46 I wonder if AI can answer that.
00:23:46 --> 00:23:47 What is the mass of the Earth in
00:23:47 --> 00:23:49 dollars? I bet it can.
00:23:49 --> 00:23:51 I'll I'll do it in US dollars cuz, you
00:23:51 --> 00:23:53 know, Australian dollars it'll just say
00:23:53 --> 00:23:58 10 bucks.
00:23:58 --> 00:23:59 Oh, dear.
00:23:59 --> 00:24:01 Yeah.
00:24:01 --> 00:24:02 I wonder if AI will come up with a
00:24:02 --> 00:24:04 number.
00:24:04 --> 00:24:06 It might. I think AI's going to be
00:24:06 --> 00:24:06 smart.
00:24:06 --> 00:24:09 did. 5 quadrillion US dollars.
00:24:09 --> 00:24:11 That's what the Earth is worth.
00:24:11 --> 00:24:15 I thought Elon Musk had that much money.
00:24:15 --> 00:24:17 Anyway.
00:24:17 --> 00:24:18 There you go.
00:24:18 --> 00:24:20 Nobody can say we're not adequate with
00:24:20 --> 00:24:20 answers now.
00:24:20 --> 00:24:22 being very thorough when it comes to
00:24:22 --> 00:24:24 money.
00:24:24 --> 00:24:25 Well, some people are. I haven't got
00:24:25 --> 00:24:26 any.
00:24:26 --> 00:24:28 All right. Thanks, Mike. Thanks for the
00:24:28 --> 00:24:30 question. Hope we adequately covered it
00:24:30 --> 00:24:31 for you.
00:24:31 --> 00:24:34 Suspect not. But anyway, we'll um
00:24:34 --> 00:24:39 we might do a sequel one day.
00:24:39 --> 00:24:40
00:24:40 --> 00:24:40
00:24:40 --> 00:24:41
00:24:41 --> 00:24:43 Space Nuts
00:24:43 --> 00:24:45 Our final question on Space Nuts today
00:24:45 --> 00:24:49 Fred comes from Eduardo who is from Gran
00:24:49 --> 00:24:52 Canaria in the Canary Islands. Lovely.
00:24:52 --> 00:24:52 Um
00:24:52 --> 00:24:55 we drove past there last year in in a
00:24:55 --> 00:24:56 ship.
00:24:56 --> 00:24:57 We we got to wave. We were supposed to
00:24:57 --> 00:24:59 stop there but um
00:24:59 --> 00:25:01 the schedule changed so we we ended up
00:25:01 --> 00:25:02 um
00:25:02 --> 00:25:03 at um
00:25:03 --> 00:25:05 uh Tenerife instead.
00:25:05 --> 00:25:08 Uh so Eduardo asked, "Do neutrinos
00:25:08 --> 00:25:10 interact with gravity at all? Do they
00:25:10 --> 00:25:12 get swallowed by black holes or do they
00:25:12 --> 00:25:14 just shoot through them like ordinary
00:25:14 --> 00:25:15 matter?
00:25:15 --> 00:25:18 Uh light is massless, moves at the speed
00:25:18 --> 00:25:20 of light and yet can't shoot through the
00:25:20 --> 00:25:22 Earth like neutrinos do, hardly
00:25:22 --> 00:25:24 interacting with matter at all. Although
00:25:24 --> 00:25:26 I imagine it would be hard even for
00:25:26 --> 00:25:28 neutrinos to shoot through a point of
00:25:28 --> 00:25:32 infinite uh density. I suppose that
00:25:32 --> 00:25:34 point, the so-called singularity, is all
00:25:34 --> 00:25:37 the way uh down the gravity well of a
00:25:37 --> 00:25:40 black hole. Not all of the black hole
00:25:40 --> 00:25:42 volume from the event horizon to
00:25:42 --> 00:25:45 significantly uh to the singularity has
00:25:45 --> 00:25:46 infinite
00:25:46 --> 00:25:49 uh density, I guess. Or does it? What
00:25:49 --> 00:25:51 about space-time itself? Bodies with
00:25:51 --> 00:25:53 huge mass and gravitational influence
00:25:53 --> 00:25:56 bend space-time. They can also make it
00:25:56 --> 00:25:58 vibrate, generating gravitational waves
00:25:58 --> 00:26:00 if the interaction is strong enough,
00:26:00 --> 00:26:02 making space-time somewhat of a material
00:26:02 --> 00:26:04 in nature.
00:26:04 --> 00:26:06 Could huge supermassive black holes feed
00:26:06 --> 00:26:09 on space-time itself? Thanks for your
00:26:09 --> 00:26:11 answers, Eduardo."
00:26:11 --> 00:26:13 Thought-provoking.
00:26:13 --> 00:26:16 Mhm. It is, yeah. Um I uh also have
00:26:16 --> 00:26:18 visited Gran Canaria
00:26:18 --> 00:26:20 um
00:26:20 --> 00:26:23 many times um on my usually on my way to
00:26:23 --> 00:26:25 La Palma where I used to observe a lot
00:26:25 --> 00:26:26 on the um
00:26:26 --> 00:26:28 William Herschel Telescope on the island
00:26:28 --> 00:26:29 of La Palma.
00:26:29 --> 00:26:30 Yeah.
00:26:30 --> 00:26:33 Uh it's a lovely part of the world. Uh
00:26:33 --> 00:26:35 my last trip there was
00:26:35 --> 00:26:38 kind of disappointing because um Nandy
00:26:38 --> 00:26:40 was supposed to come with me, but for
00:26:40 --> 00:26:41 reasons beyond our control, she
00:26:41 --> 00:26:43 couldn't. So, I ended up there on my own
00:26:43 --> 00:26:45 doing a conference. Anyway, that's a
00:26:45 --> 00:26:47 long story.
00:26:47 --> 00:26:50 Um Um okay. Uh
00:26:50 --> 00:26:53 so, the basic question
00:26:53 --> 00:26:55 uh is, let me just read the question. Do
00:26:55 --> 00:26:58 in Do you neutrinos interact with
00:26:58 --> 00:26:59 gravity at all?
00:26:59 --> 00:27:00 Mhm.
00:27:00 --> 00:27:02 And the answer is yes,
00:27:02 --> 00:27:02 um
00:27:02 --> 00:27:06 because they've got um a nonzero rest
00:27:06 --> 00:27:07 mass.
00:27:07 --> 00:27:09 Unlike a photon, which has a zero rest
00:27:09 --> 00:27:10 mass,
00:27:10 --> 00:27:14 um a neutrino has a nonzero rest mass,
00:27:14 --> 00:27:16 but is very, very small.
00:27:16 --> 00:27:18 But nevertheless, uh that is enough to
00:27:18 --> 00:27:21 mean that it follows the curvature of
00:27:21 --> 00:27:24 space-time exactly as defined by general
00:27:24 --> 00:27:27 relativity. So, they do interact with
00:27:27 --> 00:27:28 gravity.
00:27:28 --> 00:27:30 Um and the
00:27:30 --> 00:27:32 you know, that's the that's the the
00:27:32 --> 00:27:34 basically the crucial point about all
00:27:34 --> 00:27:35 this.
00:27:35 --> 00:27:40 Uh if a neutrino crosses the event
00:27:40 --> 00:27:43 horizon of a black hole,
00:27:43 --> 00:27:43 uh
00:27:43 --> 00:27:47 they uh they do get swallowed um
00:27:47 --> 00:27:50 by a black hole. Uh
00:27:50 --> 00:27:52 so,
00:27:52 --> 00:27:56 it's the ones that are probably moving
00:27:56 --> 00:27:58 quickly enough that avoid being
00:27:58 --> 00:27:59 swallowed. But because they've they've
00:27:59 --> 00:28:01 got mass,
00:28:01 --> 00:28:03 and black holes love eating mass, that
00:28:03 --> 00:28:05 means they just basically get swallowed.
00:28:05 --> 00:28:06 Generally speaking.
00:28:06 --> 00:28:08 get much out of a neutrino.
00:28:08 --> 00:28:10 No, that's not right. They're certainly
00:28:10 --> 00:28:13 not sustained by a neutrino um in terms
00:28:13 --> 00:28:14 of sustenance.
00:28:14 --> 00:28:17 Um so, yes, that's basically the
00:28:17 --> 00:28:19 question that um they they do get
00:28:19 --> 00:28:23 swallowed. They don't just shoot through
00:28:23 --> 00:28:23 uh
00:28:23 --> 00:28:26 them, you know, like
00:28:26 --> 00:28:28 well, like nothing does really.
00:28:28 --> 00:28:30 And yet, they say they can pass through
00:28:30 --> 00:28:31 Earth.
00:28:31 --> 00:28:34 Yeah, but that's because their mass and
00:28:34 --> 00:28:37 their you know, their interact if I can
00:28:37 --> 00:28:39 put it this way, their interactability
00:28:39 --> 00:28:40 with other
00:28:40 --> 00:28:42 uh subatomic particles is so low,
00:28:42 --> 00:28:44 they're weakly interacting, very, very
00:28:44 --> 00:28:46 weakly interacting. So, they just zoom
00:28:46 --> 00:28:47 through the Earth.
00:28:47 --> 00:28:47 Yeah.
00:28:47 --> 00:28:48 Uh
00:28:48 --> 00:28:51 but they still have mass.
00:28:51 --> 00:28:54 Uh but only a tiny amount, and so they
00:28:54 --> 00:28:56 will be sucked into a black hole.
00:28:56 --> 00:28:57 Mhm.
00:28:57 --> 00:28:58 Uh and that was the second part of his
00:28:58 --> 00:29:01 question. Uh and then the crux of that
00:29:01 --> 00:29:03 was could a super massive black hole
00:29:03 --> 00:29:06 feed on space-time itself?
00:29:06 --> 00:29:07 Um
00:29:07 --> 00:29:10 I I I don't think so, because uh
00:29:10 --> 00:29:11 space-time
00:29:11 --> 00:29:13 it is
00:29:13 --> 00:29:15 you know, it I mean
00:29:15 --> 00:29:18 essentially Eduardo's suggesting that
00:29:18 --> 00:29:21 space-time is material in nature.
00:29:21 --> 00:29:21 Mhm.
00:29:21 --> 00:29:23 But it's not, it's the medium, if I can
00:29:23 --> 00:29:25 put it that way. It's not a medium, it's
00:29:25 --> 00:29:27 just a framework within which everything
00:29:27 --> 00:29:28 else sits.
00:29:28 --> 00:29:30 Uh so, um
00:29:30 --> 00:29:32 a black hole feeding on space-time I
00:29:32 --> 00:29:34 think would be out of the question.
00:29:34 --> 00:29:35 There's plenty of other stuff within
00:29:35 --> 00:29:37 that space-time for it to feed on, which
00:29:37 --> 00:29:39 is material in nature.
00:29:39 --> 00:29:41 Uh but not space-time itself.
00:29:41 --> 00:29:44 Yeah. Okay.
00:29:44 --> 00:29:47 Very good. Did I think we covered it.
00:29:47 --> 00:29:48 Um I I hope so.
00:29:48 --> 00:29:49 Yeah.
00:29:51 --> 00:29:54 All right. Uh thank you, Eduardo. Um
00:29:54 --> 00:29:56 thanks for sending the question in, and
00:29:56 --> 00:29:57 a reminder if you'd like to send us
00:29:57 --> 00:29:59 questions, please do. Just go to our
00:29:59 --> 00:30:02 website, spacenuts.podcast .com or
00:30:02 --> 00:30:05 spacenuts.io. There's a little link at
00:30:05 --> 00:30:07 the top called AMA.
00:30:07 --> 00:30:08 Ask me anything. You click on that, and
00:30:08 --> 00:30:11 you can send us text or audio questions.
00:30:11 --> 00:30:13 Uh just fill in the blanks. Uh if you've
00:30:13 --> 00:30:15 got a device, a smart device with a
00:30:15 --> 00:30:16 microphone, you're all set. Just don't
00:30:16 --> 00:30:18 forget to tell us who you are and where
00:30:18 --> 00:30:20 you're from. We just like to know so we
00:30:20 --> 00:30:23 can spam you.
00:30:23 --> 00:30:25 I wish that was not true, but I have
00:30:25 --> 00:30:27 actually spammed a couple of people
00:30:27 --> 00:30:28 lately with
00:30:28 --> 00:30:31 you know, some book that I was trying to
00:30:31 --> 00:30:32 flog.
00:30:32 --> 00:30:34 Yeah. Um
00:30:34 --> 00:30:35 and thanks for those who have
00:30:35 --> 00:30:38 bought it, and even bigger thanks to
00:30:38 --> 00:30:40 those who read it. I appreciate that.
00:30:40 --> 00:30:43 Um cuz I I've gone um I've gone Kindle
00:30:43 --> 00:30:45 Plus on it, Fred, and
00:30:45 --> 00:30:47 uh it gives me a report every day of how
00:30:47 --> 00:30:49 many pages have been read. Which is
00:30:49 --> 00:30:53 fascinating cuz I get paid per page.
00:30:53 --> 00:30:55 Okay. Oh, that's interesting. Per page
00:30:55 --> 00:30:55 read.
00:30:55 --> 00:30:58 Yeah. So, you you you get you get um
00:30:58 --> 00:31:00 so many cents per page. I earned 5 cents
00:31:00 --> 00:31:02 yesterday.
00:31:02 --> 00:31:03 After tax, that'd
00:31:03 --> 00:31:06 be 1 and 1/2 cents.
00:31:06 --> 00:31:08 It's um not really comparable with the
00:31:08 --> 00:31:10 mass of the Earth in dollars, is it?
00:31:10 --> 00:31:11 No, not really.
00:31:11 --> 00:31:13 No.
00:31:13 --> 00:31:15 Yeah, I never thought of it that way.
00:31:15 --> 00:31:17 But anyway, it's it's just fun to do it.
00:31:17 --> 00:31:19 Now, I enjoy the writing and I enjoy the
00:31:19 --> 00:31:21 I don't really enjoy the marketing side
00:31:21 --> 00:31:25 of things. That's That's not my jam.
00:31:25 --> 00:31:27 Mhm, that's right.
00:31:27 --> 00:31:28 Anyway.
00:31:28 --> 00:31:30 Uh so, yes, keep those cards and letters
00:31:30 --> 00:31:33 coming in. Love to hear from you and uh
00:31:33 --> 00:31:35 thank you, Fred, as always for answering
00:31:35 --> 00:31:38 those questions so thoroughly.
00:31:38 --> 00:31:40 Well, thank you, Andrew. I yeah
00:31:40 --> 00:31:41 I I'm glad you think they were
00:31:41 --> 00:31:43 thoroughly answered. That's all right.
00:31:43 --> 00:31:45 Or adequately.
00:31:45 --> 00:31:46 I'll
00:31:46 --> 00:31:48 I'll I'll take that one. Thank you.
00:31:48 --> 00:31:50 Fair enough. I'll see I'll see you soon,
00:31:50 --> 00:31:51 Fred. Thank you.
00:31:51 --> 00:31:52 Yeah. Cheers for now. Bye-bye.
00:31:52 --> 00:31:53 Professor Fred Watson,
00:31:53 --> 00:31:55 astronomer-at-large, and thanks to Hugh
00:31:55 --> 00:31:57 in the studio. Uh couldn't be with us
00:31:57 --> 00:32:00 today because he underestimated his mass
00:32:00 --> 00:32:02 and he's had to go to the gym. And from
00:32:02 --> 00:32:04 me, Andrew Dunkley, uh we'll see you on
00:32:04 --> 00:32:06 the next episode of Space Nuts. Until
00:32:06 --> 00:32:07 then, bye-bye.
00:32:07 --> 00:32:10 Space Nuts. You've been listening to the
00:32:10 --> 00:32:12 Space Nuts podcast.
00:32:12 --> 00:32:16 Available at Apple podcasts, Spotify,
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00:32:21 --> 00:32:23 bytes.com. This has been another quality
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