Archived Insights: Gravitational Waves, Earth's Fate, and Dark Energy
In this special episode of Space Nuts, hosts Andrew Dunkley and Professor Fred Watson take a trip down memory lane, revisiting some of the most compelling questions from their Q&A sessions. This episode features discussions on gravitational waves produced by the Big Bang, a thought-provoking "what if" scenario regarding the Earth's fate if the Sun never dies, and a deep dive into the enigmatic nature of dark energy.
Episode Highlights:
- Gravitational Waves and the Big Bang: Andrew and Fred tackle a listener's inquiry about whether the Big Bang generated gravitational waves and how these might be detected alongside the cosmic microwave background radiation.
- The Fate of Earth: A "what if" question explores the implications of an immortal Sun and how Earth's environment might evolve, leading to fascinating speculations about tidal locking and atmospheric changes.
- Time and Dark Energy: The hosts discuss a listener's theory proposing a connection between time and dark energy, addressing the complexities of cosmic expansion and the role of gravity in shaping our understanding of the universe.
For more Space Nuts, including our continuously updating newsfeed and to listen to all our episodes, visit our website. 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.
If you’d like to help support Space Nuts and join our growing family of insiders for commercial-free episodes and more, visit spacenutspodcast.com/about.
Stay curious, keep looking up, and join us next time for more stellar insights and cosmic wonders. Until then, clear skies and happy stargazing.
Become a supporter of this podcast: https://www.spreaker.com/podcast/space-nuts-astronomy-insights-cosmic-discoveries--2631155/support.
00:00:00 --> 00:00:01 Andrew Dunkley: While the world takes a little bit of a rest
00:00:01 --> 00:00:03 over the Christmas New Year period. We
00:00:03 --> 00:00:06 thought we would, too. But we're not going to
00:00:06 --> 00:00:08 leave you hanging. We've dug into the
00:00:08 --> 00:00:10 archives and found a few of the biggest
00:00:10 --> 00:00:13 episodes of recent times. So sit
00:00:13 --> 00:00:15 back and enjoy those. And we'll be back with
00:00:15 --> 00:00:18 new episodes of Space Nuts, probably in
00:00:18 --> 00:00:21 the middle of January. See you then, Space
00:00:21 --> 00:00:23 Nuts. Hi there. Thanks for joining us. This
00:00:23 --> 00:00:26 is Space Nuts, Q and A. My name is Andrew
00:00:26 --> 00:00:29 Dunkley, your host. And coming up on this
00:00:29 --> 00:00:31 episode, we've got a question about
00:00:31 --> 00:00:33 gravitational waves and the Big Bang. We're
00:00:33 --> 00:00:35 also going to look, at a what if question.
00:00:35 --> 00:00:38 Love the what if questions. which is asking
00:00:38 --> 00:00:40 about, the life of Earth. Not life on
00:00:40 --> 00:00:43 Earth, the life of Earth. if
00:00:43 --> 00:00:46 the sun never died. Interesting,
00:00:47 --> 00:00:50 angle. And we're also going to look at, time
00:00:50 --> 00:00:52 and dark energy. That's all coming
00:00:52 --> 00:00:55 up on the Q A edition of space
00:00:55 --> 00:00:56 nuts.
00:00:56 --> 00:00:58 Generic: 15 seconds. Guidance is internal.
00:00:59 --> 00:01:01 10, 9. Ignition
00:01:02 --> 00:01:04 sequence time. Space nuts. 5, 4, 3,
00:01:04 --> 00:01:07 2, 1. 2, 3, 4, 5, 5, 4,
00:01:07 --> 00:01:10 3, 2', 1. Space nuts.
00:01:10 --> 00:01:11 Generic: Astronauts report it feels good.
00:01:12 --> 00:01:14 Andrew Dunkley: And joining me once again is Professor Fred
00:01:14 --> 00:01:16 Watson, astronomer at large. Hello, Fred.
00:01:16 --> 00:01:17 Professor Fred Watson: Hey, Andrew. How are you doing?
00:01:18 --> 00:01:20 Andrew Dunkley: I'm doing as much as I can.
00:01:20 --> 00:01:22 Professor Fred Watson: Good, good, good. Good to be Q and A with
00:01:22 --> 00:01:23 you.
00:01:23 --> 00:01:26 Andrew Dunkley: Yes, you too. shall we get stuck
00:01:26 --> 00:01:27 straight in?
00:01:27 --> 00:01:28 Professor Fred Watson: Why not? Yes, why not?
00:01:28 --> 00:01:31 Andrew Dunkley: All right. our first question comes. I'm not
00:01:31 --> 00:01:33 sure if it's BO or boa. I'll have to listen
00:01:33 --> 00:01:34 more carefully. Here we go.
00:01:36 --> 00:01:38 Beau: Hello, Fred and Andrew. It's Bo here from
00:01:38 --> 00:01:41 Melbourne. I hope you're well. I have a
00:01:41 --> 00:01:44 question for you. And it is not about dark
00:01:44 --> 00:01:46 energy, nor it is about dark matter,
00:01:47 --> 00:01:49 but it is about gravitational waves.
00:01:49 --> 00:01:52 It's a straightforward question. Did the
00:01:52 --> 00:01:55 Big Bang produce gravitational waves
00:01:56 --> 00:01:58 as we understand it? Gravitational waves, are
00:01:58 --> 00:02:00 generated when two massive bodies such as
00:02:00 --> 00:02:03 neutron stars and black holes collided with
00:02:03 --> 00:02:05 each other and cause that ripple in the
00:02:05 --> 00:02:08 fabric of space time. But
00:02:08 --> 00:02:10 when the universe has just
00:02:10 --> 00:02:13 began, infinite density and so forth.
00:02:14 --> 00:02:16 When it came into existence via the Big Bang,
00:02:16 --> 00:02:19 did it produce gravitational waves or echoes?
00:02:21 --> 00:02:23 And can we detect those echoes in space and
00:02:23 --> 00:02:26 time? Very much like the cosmic microwave
00:02:26 --> 00:02:28 background radiation that we see today.
00:02:29 --> 00:02:31 Anyway, I hope that made sense. I'd love to
00:02:31 --> 00:02:32 hear your answer. Thank you very much.
00:02:33 --> 00:02:35 Andrew Dunkley: Thank you. Boa. that's a good question.
00:02:36 --> 00:02:38 We talk about the Big Bang a lot. We get a
00:02:38 --> 00:02:39 lot of questions about it.
00:02:41 --> 00:02:43 and, I mean, it was
00:02:44 --> 00:02:47 a massive event. We don't know why
00:02:47 --> 00:02:50 we don't know a lot, but, we
00:02:50 --> 00:02:52 know we can see that it happened through the
00:02:52 --> 00:02:55 cosmic microwave background radiation that's
00:02:55 --> 00:02:57 still evident today. But
00:02:57 --> 00:03:00 gravitational waves would. I
00:03:00 --> 00:03:03 mean, if the universe didn't exist at
00:03:03 --> 00:03:05 the moment of the Big Bang and was being
00:03:05 --> 00:03:07 created as a consequence of that,
00:03:08 --> 00:03:11 I'm not sure gravitational waves could have
00:03:11 --> 00:03:13 happened the way we understand them with
00:03:13 --> 00:03:15 other events in our universe.
00:03:16 --> 00:03:18 I'm not sure about this one.
00:03:19 --> 00:03:21 Professor Fred Watson: So, the thing is, Andrew,
00:03:22 --> 00:03:24 Yes, the universe was created in that
00:03:24 --> 00:03:26 instant, of the Big Bang.
00:03:27 --> 00:03:30 and so you're right. you know, in the
00:03:30 --> 00:03:32 conventional theory, standard Einsteinian
00:03:32 --> 00:03:35 physics, we imagine that time
00:03:35 --> 00:03:37 and space didn't exist before the Big Bang.
00:03:37 --> 00:03:40 So, you've got to create some space for your
00:03:40 --> 00:03:43 gravitational waves to go through. which is
00:03:43 --> 00:03:43 kind of what.
00:03:43 --> 00:03:44 Andrew Dunkley: That's what I'm thinking.
00:03:44 --> 00:03:47 Professor Fred Watson: Yeah. And so, And so, yes, there
00:03:47 --> 00:03:49 was the instant of the Big Bang that
00:03:49 --> 00:03:52 created this singularity in
00:03:52 --> 00:03:55 time and space, followed by this
00:03:55 --> 00:03:58 period. Was it 10 to the minus 33 of a
00:03:58 --> 00:04:00 second, something like that in duration,
00:04:01 --> 00:04:03 which we call the period of inflation when
00:04:03 --> 00:04:06 the. When the expansion really
00:04:06 --> 00:04:09 took hold. and it, you know, the universe
00:04:09 --> 00:04:11 went from the size of a football to the size
00:04:11 --> 00:04:14 of a galaxy in something like 10 to the minus
00:04:14 --> 00:04:16 33 of a second. And,
00:04:16 --> 00:04:19 the thinking is, and I'm
00:04:19 --> 00:04:22 actually dragging this up from reading a few
00:04:22 --> 00:04:24 years ago, but yes,
00:04:25 --> 00:04:27 that inflationary period, as we call it,
00:04:28 --> 00:04:30 would have created gravitational waves,
00:04:33 --> 00:04:35 or maybe a gravitational wave.
00:04:36 --> 00:04:38 Andrew Dunkley: But I was about to say maybe just
00:04:38 --> 00:04:40 one big one at that point.
00:04:40 --> 00:04:43 Professor Fred Watson: But the issue is, that,
00:04:44 --> 00:04:46 it is a gravitational wave, a
00:04:46 --> 00:04:49 very, very, very low frequency.
00:04:50 --> 00:04:52 So, the gravitational waves that we get from
00:04:52 --> 00:04:54 colliding neutron stars, for example,
00:04:55 --> 00:04:58 they produce waves
00:04:58 --> 00:05:01 which are, basically have a frequency which
00:05:01 --> 00:05:03 is in the audio range. Which is why we can,
00:05:04 --> 00:05:06 you know, turn those, gravitational wave
00:05:06 --> 00:05:09 signals into an signal very easily
00:05:09 --> 00:05:11 after you've amplified it up a bit and after
00:05:11 --> 00:05:14 LIGO has done its magic on it. And that's
00:05:14 --> 00:05:16 where we get this chirp signal
00:05:17 --> 00:05:20 as two neutron stars, m or whatever, merge
00:05:20 --> 00:05:23 together, and eventually, because
00:05:23 --> 00:05:25 they're spinning ever more rapidly, and so
00:05:25 --> 00:05:27 the frequency goes up of the waves that are
00:05:27 --> 00:05:30 being emitted and then stop, at a high
00:05:30 --> 00:05:32 point because that's where they've coalesced
00:05:32 --> 00:05:34 into a single object. now
00:05:35 --> 00:05:36 you can think of those,
00:05:38 --> 00:05:40 audio frequencies. you know,
00:05:40 --> 00:05:43 we might talk about something like 500 hertz
00:05:43 --> 00:05:46 as an audio frequency. Or
00:05:46 --> 00:05:49 you could take 440 hertz as the frequency
00:05:49 --> 00:05:51 of, the standard, a note
00:05:52 --> 00:05:53 in the musical spectrum.
00:05:55 --> 00:05:57 so let's stick with 500 because that's an
00:05:57 --> 00:06:00 easy one. so the, the period
00:06:00 --> 00:06:03 of time between one peak of the
00:06:03 --> 00:06:05 wave and the next, is
00:06:05 --> 00:06:08 1-500th of a second. And so
00:06:08 --> 00:06:11 if you think that's the interval of time
00:06:11 --> 00:06:14 of a characteristic gravitational wave from
00:06:15 --> 00:06:18 two colliding objects. Now the
00:06:18 --> 00:06:21 issue as I understand it, is that
00:06:21 --> 00:06:23 the interval between peaks
00:06:23 --> 00:06:25 in a gravitational wave,
00:06:26 --> 00:06:28 produced by inflation
00:06:29 --> 00:06:32 is about the same as the age of the universe.
00:06:32 --> 00:06:34 Now it's not 1-500th
00:06:34 --> 00:06:36 of a second, it's you know,
00:06:37 --> 00:06:40 several billion years, perhaps even
00:06:41 --> 00:06:43 tens of billions of years. it's quite a while
00:06:43 --> 00:06:46 since I read up on this. So normal
00:06:46 --> 00:06:49 gravitational wave technology is simply not
00:06:49 --> 00:06:51 equipped to detect these low frequency,
00:06:52 --> 00:06:54 ultra ultra low frequency gravitational
00:06:54 --> 00:06:56 waves. But there might be other ways of
00:06:56 --> 00:06:59 seeing them. and one of the things people
00:06:59 --> 00:07:01 have looked for, and I'm not really
00:07:02 --> 00:07:05 very well up on this, but
00:07:05 --> 00:07:08 there is a potential signal
00:07:08 --> 00:07:10 in the cosmic microwave background radiation,
00:07:11 --> 00:07:13 the flash of the Big Bang that we see, that
00:07:13 --> 00:07:15 gives us what the Universe looked like
00:07:15 --> 00:07:18 380 years after the Big Bang. That's what
00:07:18 --> 00:07:21 we're seeing there. that
00:07:21 --> 00:07:23 radiation, contains information
00:07:24 --> 00:07:27 not just on its brightness, but also on its
00:07:27 --> 00:07:29 polarization. you know, that
00:07:29 --> 00:07:31 radiation is polarized, a bit like light can
00:07:31 --> 00:07:34 be polarized. And I'm not
00:07:34 --> 00:07:37 really drawing the links very
00:07:37 --> 00:07:39 strongly here, but I understand that there
00:07:39 --> 00:07:42 are links between very low frequency
00:07:42 --> 00:07:44 gravitational waves and that polarization
00:07:44 --> 00:07:46 signal. So it's one of the things that people
00:07:46 --> 00:07:48 are looking for to try and detect this
00:07:48 --> 00:07:51 polarization, within cosmic matter
00:07:51 --> 00:07:53 wave background radiation. So it's not at all
00:07:53 --> 00:07:56 a daft question, but it's quite a complex
00:07:56 --> 00:07:56 answer.
00:07:57 --> 00:08:00 Andrew Dunkley: Yeah, yeah, but the, the Big Bang itself
00:08:00 --> 00:08:03 could have initially been
00:08:03 --> 00:08:06 one created one gravitational wave.
00:08:06 --> 00:08:08 Professor Fred Watson: That's right, yeah. That's more or less it.
00:08:09 --> 00:08:12 Andrew Dunkley: M goa. you're right on the money.
00:08:13 --> 00:08:15 It's just a matter of finding a way of
00:08:15 --> 00:08:18 seeing them. is it possible these
00:08:18 --> 00:08:20 gravitational waves still bouncing around
00:08:20 --> 00:08:22 like the cosmic microwave background radio?
00:08:22 --> 00:08:25 Professor Fred Watson: Yes, yes, but at such a low frequency that
00:08:25 --> 00:08:27 you don't actually know it's there. You've
00:08:27 --> 00:08:29 got to find other, you've got to find other
00:08:29 --> 00:08:31 ways of detecting it because there's not
00:08:31 --> 00:08:33 going to be any change in the gravitational
00:08:33 --> 00:08:35 wave signal over, you know, a human
00:08:35 --> 00:08:37 experimental lifetime. If you've got
00:08:38 --> 00:08:41 a frequency whose time interval is measured
00:08:41 --> 00:08:42 in billions of years, forget it.
00:08:42 --> 00:08:44 Andrew Dunkley: Yeah, that's a tough one.
00:08:47 --> 00:08:47 Professor Fred Watson: Thanks.
00:08:47 --> 00:08:49 Andrew Dunkley: Boa. That's a great question and thanks for
00:08:49 --> 00:08:50 sending it in.
00:08:50 --> 00:08:52 we've got a question from one of our
00:08:52 --> 00:08:55 regulars, Rennie, who is from sunny West
00:08:55 --> 00:08:57 Hills, California. this is a what if
00:08:57 --> 00:08:59 question. Theoretically, if the sun were
00:08:59 --> 00:09:01 never to die, let's assum. Assume it's just
00:09:01 --> 00:09:03 never going to die. Would the Earth
00:09:04 --> 00:09:05 eventually erode, decay
00:09:06 --> 00:09:08 and die on its own?
00:09:09 --> 00:09:09 Professor Fred Watson: yeah.
00:09:11 --> 00:09:13 Andrew Dunkley: Well, my answer is no, because we'll destroy
00:09:13 --> 00:09:14 it first.
00:09:15 --> 00:09:17 Professor Fred Watson: It could be very different. I mean, so if
00:09:17 --> 00:09:20 what Ren is saying is that, yes, the sun, we
00:09:20 --> 00:09:21 know it's going to evolve over the next few
00:09:21 --> 00:09:24 billion years, and it will change and that
00:09:24 --> 00:09:25 will eventually result in the Earth being
00:09:25 --> 00:09:27 swamped by the outer atmosphere of the sun,
00:09:27 --> 00:09:30 which might not be very nice for anybody left
00:09:30 --> 00:09:33 on Earth. but if that
00:09:33 --> 00:09:34 didn't happen, if the sun just
00:09:36 --> 00:09:38 went on its merry way, being a normal star,
00:09:40 --> 00:09:42 there will be a few things that will happen
00:09:42 --> 00:09:43 over that time scale
00:09:45 --> 00:09:47 which we know won't happen because
00:09:48 --> 00:09:50 the sun turning into a red giant is going to
00:09:50 --> 00:09:52 overtake it. One of them is,
00:09:53 --> 00:09:55 the tidal
00:09:56 --> 00:09:58 breaking of the Earth's rotation so that it
00:09:58 --> 00:10:01 always, faces the Moon. So the Earth's day
00:10:01 --> 00:10:03 will change from
00:10:04 --> 00:10:06 24 hours to something like, if I remember
00:10:06 --> 00:10:09 rightly, it's 42 days, that it's about that
00:10:09 --> 00:10:12 length of time, and that's it turning once.
00:10:12 --> 00:10:15 And the Moon will go around the
00:10:15 --> 00:10:17 sky, around the Earth in the same time. So
00:10:17 --> 00:10:20 the Earth and the Moon will constantly face
00:10:20 --> 00:10:22 one another with ah, a month and a day, which
00:10:22 --> 00:10:24 are both equivalent to, I think it's about
00:10:24 --> 00:10:26 42, 43 days, something like that.
00:10:27 --> 00:10:29 so that's going to change things quite a bit.
00:10:30 --> 00:10:33 so that would certainly alter the
00:10:33 --> 00:10:35 atmospheric dynamics of the Earth if one
00:10:35 --> 00:10:38 side's getting warmed up for 20 days rather
00:10:38 --> 00:10:41 than just one day, of day and night. So
00:10:41 --> 00:10:44 a lot of things change. and yeah,
00:10:44 --> 00:10:46 the constant bombardment by the
00:10:47 --> 00:10:49 magnetic particles from the sun,
00:10:50 --> 00:10:51 I don't know to what extent the Earth's
00:10:51 --> 00:10:53 magnetic field might erode, but there will
00:10:53 --> 00:10:56 certainly be changes, may
00:10:56 --> 00:10:56 even be.
00:10:56 --> 00:10:57 Andrew Dunkley: What about.
00:10:58 --> 00:10:59 Professor Fred Watson: So go ahead, go on.
00:11:00 --> 00:11:02 Andrew Dunkley: No, I was just going to say if humans were
00:11:02 --> 00:11:05 still around in that period, would we.
00:11:06 --> 00:11:08 Well, okay, no, let me rephrase. Would we
00:11:08 --> 00:11:11 adapt as these things changed and
00:11:11 --> 00:11:13 reached that point? Would we be able to adapt
00:11:13 --> 00:11:16 as a species and other life on Earth, adapt
00:11:16 --> 00:11:18 to live in that kind of environment?
00:11:18 --> 00:11:20 Professor Fred Watson: Well, it certainly is. All these changes are
00:11:20 --> 00:11:23 ones that take place very slowly indeed. and
00:11:23 --> 00:11:26 over kind of longer periods than the
00:11:26 --> 00:11:28 characteristic evolution time to get
00:11:28 --> 00:11:31 from, you know, one mutation to another,
00:11:31 --> 00:11:32 whatever that might be for humans.
00:11:34 --> 00:11:36 so yeah, they're slow and
00:11:37 --> 00:11:40 I'm sure humans could adapt to them. we're a
00:11:40 --> 00:11:42 pretty adaptive species. We might also by
00:11:42 --> 00:11:44 then be capable of building the
00:11:44 --> 00:11:46 megastructures that might protect us from
00:11:46 --> 00:11:49 some of the sun's funny things going on.
00:11:49 --> 00:11:52 it's hard to know really, isn't it? But
00:11:52 --> 00:11:54 I think generally speaking, I mean, Rennie's
00:11:54 --> 00:11:56 question's a good. What happens if
00:11:57 --> 00:11:59 nothing happens to the sun? does the Earth
00:11:59 --> 00:12:01 just sort of survive? It probably
00:12:02 --> 00:12:04 survives. It will be changed. We might find
00:12:04 --> 00:12:06 we're all living in plastic domes or
00:12:06 --> 00:12:09 something by then, rather than because the
00:12:09 --> 00:12:12 atmosphere has been so messed about with. But
00:12:12 --> 00:12:14 yes, I think I'm an
00:12:14 --> 00:12:16 optimist that humankind would survive.
00:12:17 --> 00:12:19 Andrew Dunkley: Yeah, no, it's interesting because.
00:12:21 --> 00:12:23 Andrew Dunkley: I mean we know what's going to happen. We
00:12:23 --> 00:12:24 kind of know when it's going to happen. But
00:12:25 --> 00:12:28 if it didn't, it would create a whole array
00:12:28 --> 00:12:31 of new challenges for humanity because we
00:12:31 --> 00:12:34 would have to learn to live in a, very
00:12:35 --> 00:12:37 somewhat hostile environment, I imagine,
00:12:37 --> 00:12:40 because, the planet would not be the same
00:12:40 --> 00:12:42 and I can't imagine what it would be like to
00:12:42 --> 00:12:45 have a 42 long, 42 day,
00:12:45 --> 00:12:48 long day. well, you know, birthdays would
00:12:48 --> 00:12:49 be few and far between, wouldn't they?
00:12:49 --> 00:12:51 Professor Fred Watson: they would. But you, you know, we're gonna,
00:12:51 --> 00:12:53 we're gonna know what that's like very soon
00:12:53 --> 00:12:56 because the, the day on the moon is 20, you
00:12:56 --> 00:12:59 know, 29 days effectively from
00:12:59 --> 00:13:02 one right moon to another. So yeah, so
00:13:02 --> 00:13:04 we've, we've, we've already got something
00:13:04 --> 00:13:07 like that, in store for people to experience.
00:13:07 --> 00:13:09 It'll be very interesting to see what even
00:13:09 --> 00:13:12 the Artemis astronauts on the moon make of
00:13:12 --> 00:13:12 all that.
00:13:14 --> 00:13:16 Andrew Dunkley: Yeah, yeah, very interesting. Rennie, that's
00:13:16 --> 00:13:18 a great question. Thanks for sending it in,
00:13:18 --> 00:13:19 much appreciated.
00:13:19 --> 00:13:21 And next up we've got
00:13:22 --> 00:13:24 Daniel. this is a sort of dark
00:13:24 --> 00:13:26 energy question, sort of.
00:13:27 --> 00:13:30 Generic: Hey guys, Daniel from Adelaide here. There
00:13:30 --> 00:13:32 seems to be more and more discoveries lately
00:13:32 --> 00:13:34 in the very early universe that shouldn't be
00:13:34 --> 00:13:36 possible because not enough time has passed
00:13:36 --> 00:13:38 like size of galaxies or black holes. Now
00:13:38 --> 00:13:40 I've got a far out theory I'd love to share.
00:13:40 --> 00:13:43 What if time and dark energy were actually
00:13:43 --> 00:13:45 the same thing? So we know for about the
00:13:45 --> 00:13:47 second half of the universe that dark energy
00:13:47 --> 00:13:49 has been accelerating its expansion. Could
00:13:49 --> 00:13:51 this therefore mean that there was Less dark
00:13:51 --> 00:13:53 energy in the first half. And if that's the
00:13:53 --> 00:13:55 case, what if time actually went slower in
00:13:55 --> 00:13:57 the early universe? So from our perspective,
00:13:57 --> 00:13:59 what took a really short amount of time
00:14:00 --> 00:14:02 actually happened in normal time, with normal
00:14:02 --> 00:14:04 being in quotes. I'd previously asked the
00:14:04 --> 00:14:06 question on the show whether dark energy is
00:14:06 --> 00:14:08 related to black holes. I think there was a
00:14:08 --> 00:14:10 paper around the time that kind of suggested
00:14:10 --> 00:14:12 that it was. And we know, that black holes do
00:14:12 --> 00:14:14 distort time. So if time is part of the
00:14:14 --> 00:14:17 fabric of space, maybe dark
00:14:17 --> 00:14:20 energy is too. But it's actually one of the
00:14:20 --> 00:14:22 same thing. I'm expecting a very quick,
00:14:22 --> 00:14:24 simple no, but I wanted to ask anyway.
00:14:24 --> 00:14:26 Professor Fred Watson: Thanks. All right. Thanks.
00:14:26 --> 00:14:29 Andrew Dunkley: Daniel. yeah. Is, time and dark energy,
00:14:29 --> 00:14:31 are they the same thing?
00:14:31 --> 00:14:33 Professor Fred Watson: Yeah, you never get a quick and simple no
00:14:33 --> 00:14:36 from me, Daniel. It's always a long, drawn
00:14:36 --> 00:14:39 out complex. No, it's not always.
00:14:40 --> 00:14:43 I think in this case, yeah. Your thinking's
00:14:43 --> 00:14:46 interesting. we've talked recently as well
00:14:46 --> 00:14:47 about, the fact that
00:14:50 --> 00:14:53 this new controversial theory from Joe Silk
00:14:53 --> 00:14:56 et al, over in Baltimore,
00:14:56 --> 00:14:58 suggesting that perhaps black holes,
00:14:58 --> 00:15:00 supermassive black holes, came first, they
00:15:00 --> 00:15:01 were formed in the early universe. And that
00:15:01 --> 00:15:04 goes a long way to explaining, the conundrum
00:15:04 --> 00:15:05 that you mentioned at the start of your
00:15:05 --> 00:15:07 question there, that a lot seems to have
00:15:07 --> 00:15:10 happened in the first, in the first, few
00:15:11 --> 00:15:13 millions or hundreds of millions of years of
00:15:13 --> 00:15:15 the universe's existence.
00:15:16 --> 00:15:18 so we kind of understand
00:15:20 --> 00:15:23 the gravitational time dilation, effects
00:15:23 --> 00:15:25 pretty well. And they're actually quite
00:15:25 --> 00:15:27 small, from our vantage point
00:15:27 --> 00:15:30 here, 13.8 billion
00:15:30 --> 00:15:31 years later.
00:15:33 --> 00:15:36 But you're right to make the point that, dark
00:15:36 --> 00:15:38 energy only, seems to have appeared
00:15:39 --> 00:15:41 over the second half of the age of the
00:15:41 --> 00:15:43 universe. But that's more likely to be,
00:15:45 --> 00:15:48 because its measurable effect has only become
00:15:48 --> 00:15:51 apparent. We think that during the first
00:15:51 --> 00:15:53 half of the universe's age,
00:15:55 --> 00:15:57 the galaxies within the universe were close
00:15:57 --> 00:15:59 enough to each other. The gravitational
00:15:59 --> 00:16:02 attraction would have basically kept
00:16:02 --> 00:16:05 the expansion due to dark energy in check.
00:16:05 --> 00:16:07 The accelerated expansion, due to dark
00:16:07 --> 00:16:10 energy, and so it's only when you get
00:16:10 --> 00:16:12 past a kind of tipping point where
00:16:13 --> 00:16:15 suddenly the, the mass of galaxies in the
00:16:15 --> 00:16:17 universe is not enough, not strong enough
00:16:18 --> 00:16:20 gravitationally to break the
00:16:20 --> 00:16:23 acceleration of the expansion. By that I mean
00:16:23 --> 00:16:26 B R A K rather than B R E A K,
00:16:26 --> 00:16:29 it's not enough to slow it down and so the
00:16:29 --> 00:16:32 acceleration takes over. and that's why
00:16:32 --> 00:16:35 it's a tricky thing just to try and
00:16:35 --> 00:16:37 tease out. And we've talked about this
00:16:37 --> 00:16:40 recently as well. Whether the, dark
00:16:40 --> 00:16:42 energy is a constant, whether it's something
00:16:42 --> 00:16:44 that's a, factor that
00:16:44 --> 00:16:47 hasn't changed in terms of, its release
00:16:49 --> 00:16:51 as space expands. it's because there is
00:16:51 --> 00:16:54 this added impact of the gravitational pull
00:16:54 --> 00:16:57 of the galaxies, stopping us from basically
00:16:57 --> 00:16:59 seeing the effect of dark energy, the
00:16:59 --> 00:17:01 accelerated expansion of the universe back in
00:17:01 --> 00:17:03 the early universe. So I think all those
00:17:03 --> 00:17:06 things are well and truly understood and
00:17:06 --> 00:17:09 kept fairly separate by the scientists
00:17:09 --> 00:17:11 looking at them. And by that I mean time and
00:17:11 --> 00:17:14 dark energy. So that's a long, complicated
00:17:14 --> 00:17:14 move.
00:17:16 --> 00:17:18 Andrew Dunkley: Yeah, yeah. okay. Daniel
00:17:18 --> 00:17:20 Winfred says, I think these things have been
00:17:20 --> 00:17:23 long understood. That's his way of saying,
00:17:23 --> 00:17:25 you're way off, way, way
00:17:25 --> 00:17:26 off the mark.
00:17:26 --> 00:17:27 Professor Fred Watson: Go on.
00:17:30 --> 00:17:32 Andrew Dunkley: But it's worth asking because otherwise,
00:17:33 --> 00:17:34 obviously this is something people are
00:17:34 --> 00:17:36 thinking about. So it's worth asking,
00:17:37 --> 00:17:40 these different questions
00:17:40 --> 00:17:43 to, just see if it's a
00:17:43 --> 00:17:46 possibility. Thanks, Daniel. Appreciate that.
00:17:46 --> 00:17:47 Professor Fred Watson: Great question.
00:17:47 --> 00:17:49 Andrew Dunkley: if you've got questions for us, please send
00:17:49 --> 00:17:51 them in because we could always use them.
00:17:51 --> 00:17:54 just go, to our website, spacenutspodcast.com
00:17:54 --> 00:17:57 spacenuts IO and click on the various links.
00:17:57 --> 00:18:00 The AMA link will give you, access to,
00:18:00 --> 00:18:03 text and voice, audio. Or you can
00:18:03 --> 00:18:05 click on the little. It's not purple, it's
00:18:05 --> 00:18:07 green. When did they change the color of
00:18:07 --> 00:18:09 that? send us your. Oh, no, it's. It's purple
00:18:09 --> 00:18:11 when you hover on it. There you, go. send us
00:18:11 --> 00:18:14 your questions, on the right hand side of our
00:18:14 --> 00:18:16 homepage. And don't forget to tell us who you
00:18:16 --> 00:18:18 are and where you're from. Fred, we're done.
00:18:18 --> 00:18:19 Again, thank you so much.
00:18:19 --> 00:18:22 Professor Fred Watson: always a pleasure, Andrew, and I hope we'll
00:18:22 --> 00:18:23 see you then very, very soon.
00:18:24 --> 00:18:27 Andrew Dunkley: It's a distinct, possibility. Could
00:18:27 --> 00:18:30 be within 13.8 billion years, in fact.
00:18:30 --> 00:18:31 Professor Fred Watson: Yes.
00:18:31 --> 00:18:33 Andrew Dunkley: Thanks, Fred. See you soon. Fred Watson,
00:18:33 --> 00:18:36 astronomer at large. And, thanks to Huw in
00:18:36 --> 00:18:38 the studio for making our lives so much more
00:18:38 --> 00:18:40 difficult with these split episodes. But, no,
00:18:40 --> 00:18:43 it's okay. and from me, Andrew Dunkley, thank
00:18:43 --> 00:18:45 you so much for joining us. Looking forward
00:18:45 --> 00:18:47 to your company on the next episode of Space
00:18:47 --> 00:18:50 Nuts. See you then, Space Nuts.
00:18:50 --> 00:18:52 Generic: You've been listening to the Space Nuts
00:18:52 --> 00:18:55 Podcast. Available at
00:18:55 --> 00:18:57 Apple Podcasts, Spotify,
00:18:57 --> 00:19:00 iHeartRadio, or your favorite podcast
00:19:00 --> 00:19:02 player. You can also stream on demand at
00:19:02 --> 00:19:05 bitesz.com This has been another quality
00:19:05 --> 00:19:07 podcast production from Bitesz.com