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In this thought-provoking episode of Space Nuts, host Heidi Campo takes the reins while Andrew Dunkley enjoys a well-deserved holiday. Joined by the ever-insightful Professor Fred Watson, they dive into a range of captivating questions submitted by listeners. From the potential discovery of habitable exoplanets within our lifetime to the mysteries of gravitational waves and the intriguing concept of the cosmic jerk, this episode is a treasure trove of astronomical knowledge and cosmic wonder.
Episode Highlights:
- Habitable Exoplanets: Heidi and Fred discuss a question from Thomas, a year 11 student, about the likelihood of finding a habitable planet during our lifetime. Fred shares insights on the thousands of exoplanets already discovered and the promising candidates that may support life.
- Gravitational Waves and LIGO: Adriano from Italy poses an intriguing question about how LIGO measures gravitational waves from colliding black holes. Fred explains the mechanics behind these measurements and explores the potential to detect gravitational waves from the early universe.
- The Moon's Shifting Position: Anthony from Sydney wonders why the moon appears to shift so dramatically in the sky. Fred clarifies the geometry behind the moon's orbit and its relationship to the sun, providing a fascinating perspective on lunar observations.
- Space Tearing and the Big Rip: Mikey from Illinois asks if space can tear and what that would look like. Fred discusses the theoretical notion of "space tearing," the Big Rip hypothesis, and the extreme conditions required for such an event to occur.
- The Cosmic Jerk: Greg from Minnesota raises a question about the acceleration of the universe and whether it is changing at a constant rate. Fred elaborates on recent findings from the Dark Energy Survey Instrument and the implications for our understanding of cosmic expansion.
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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.
(00:00) Welcome to Space Nuts with Heidi Campo and Fred Watson
(01:10) Discussion on the potential for habitable exoplanets
(10:50) How LIGO measures gravitational waves from black holes
(20:30) The shifting position of the moon in the sky
(28:15) Exploring the concept of space tearing and the Big Rip
(35:20) The cosmic jerk and the acceleration of the universe
For commercial-free versions of Space Nuts, join us on Patreon, Supercast, Apple Podcasts, or become a supporter here: https://www.spreaker.com/podcast/space-nuts-astronomy-insights-cosmic-discoveries--2631155/support (https://www.spreaker.com/podcast/space-nuts-astronomy-insights-cosmic-discoveries--2631155/support?utm_source=rss&utm_medium=rss&utm_campaign=rss) .
Episode link: https://play.headliner.app/episode/26706399?utm_source=youtube
00:00:00 --> 00:00:03 You are listening to another wonderful
00:00:03 --> 00:00:06 episode of Space Nuts and I am your host
00:00:06 --> 00:00:08 for today, Heidi Compo. Well, our
00:00:08 --> 00:00:11 beloved Andrew Dunley is out on holiday.
00:00:11 --> 00:00:13 Don't worry, he will be back soon. But
00:00:13 --> 00:00:16 the brains and brun of the show, your
00:00:16 --> 00:00:20 beloved Fred Watson is here with us
00:00:20 --> 00:00:22 today. Fred, hello.
00:00:22 --> 00:00:25 Heidi, you ready to answer some
00:00:25 --> 00:00:27 questions on our Q&A episode today?
00:00:28 --> 00:00:32 Yeah, look, um, Q&A is the real meat of
00:00:32 --> 00:00:35 Space Nuts because we love people
00:00:35 --> 00:00:37 telling us what they want to hear about.
00:00:37 --> 00:00:39 It's far better than me spouting on
00:00:39 --> 00:00:40 things that they don't want to hear
00:00:40 --> 00:00:43 about. So, yep, sounds ready to go. All
00:00:43 --> 00:00:46 ready to go. And we we get just such a
00:00:46 --> 00:00:47 wonderful diverse range of questions
00:00:47 --> 00:00:50 from our listeners. Um, starting, you
00:00:50 --> 00:00:54 know, today we have uh Thomas. Dear
00:00:54 --> 00:00:56 Professor Fred Watson, my name is Thomas
00:00:56 --> 00:00:58 Wood. I'm a year 11 student doing my
00:00:58 --> 00:01:01 research project on the question and the
00:01:01 --> 00:01:04 question that I have is what is the
00:01:04 --> 00:01:07 chance of a habitable planet being found
00:01:07 --> 00:01:11 here's the key word within our lifetime.
00:01:11 --> 00:01:13 So what do you think Fred within our
00:01:13 --> 00:01:17 lifetime? Yeah I think I mean um we're
00:01:17 --> 00:01:19 talking here about planets of other
00:01:19 --> 00:01:22 stars uh exoplanets um it doesn't really
00:01:22 --> 00:01:24 matter whether they're habitable or not
00:01:24 --> 00:01:25 because they're so far away. we're never
00:01:25 --> 00:01:28 going to manage to get to them within
00:01:28 --> 00:01:30 what you might call a human time scale.
00:01:30 --> 00:01:32 Uh but there there are certainly
00:01:32 --> 00:01:35 candidates already for habitable planets
00:01:36 --> 00:01:39 among the five or 6 thousand exoplanets
00:01:39 --> 00:01:41 that we know of today and there are more
00:01:41 --> 00:01:43 being discovered all the time. There are
00:01:43 --> 00:01:45 planets that sit within the habitable
00:01:46 --> 00:01:49 zone of their parent star um and may
00:01:50 --> 00:01:51 have atmospheres that could sustain
00:01:51 --> 00:01:55 life. Those have not yet been confirmed.
00:01:55 --> 00:01:57 They've not been definitively confirmed,
00:01:57 --> 00:01:59 but I do think they will be within our
00:01:59 --> 00:02:02 lifetime. And probably Thomas, as a year
00:02:02 --> 00:02:04 11 students, your lifetime is rather
00:02:04 --> 00:02:08 longer than mine is. Uh but uh but
00:02:08 --> 00:02:10 that's all right. I can deal with that.
00:02:10 --> 00:02:12 Uh I think we'll find them within my
00:02:12 --> 00:02:14 lifetime. There you go. That's putting
00:02:14 --> 00:02:17 the that's putting the odds on it.
00:02:17 --> 00:02:19 Well, Fred, I think you have certainly
00:02:19 --> 00:02:22 done a lot with your lifetime so far,
00:02:22 --> 00:02:25 and you have really broken broken the
00:02:25 --> 00:02:27 ground for so many more to follow. Uh,
00:02:27 --> 00:02:30 our next question is an audio question.
00:02:30 --> 00:02:34 This is Adriano from Florence, Italy.
00:02:34 --> 00:02:36 Hi, Father Andreo. This is Adriano from
00:02:36 --> 00:02:39 Florence in Italy. I was listening to a
00:02:39 --> 00:02:42 conversation about LIGO, so the laser
00:02:42 --> 00:02:44 interferometer, where they explain that
00:02:44 --> 00:02:46 by measuring the gravitational waves
00:02:46 --> 00:02:48 from two colliding black holes, for
00:02:49 --> 00:02:51 example, they can also estimate the the
00:02:51 --> 00:02:54 mass of the two objects. Can you please
00:02:54 --> 00:02:57 explain how they can do that? And they
00:02:57 --> 00:03:00 also mention that with a much more
00:03:00 --> 00:03:03 sizable instrument, we should be able to
00:03:03 --> 00:03:05 measure the gravitational waves from the
00:03:05 --> 00:03:10 big bang. Is this correct? And if so, h
00:03:10 --> 00:03:13 will we be able to estimate the mass of
00:03:13 --> 00:03:16 the entire universe and therefore to
00:03:16 --> 00:03:19 confirm or deny the hypothesis around
00:03:19 --> 00:03:22 the dark energy and dark matter. Thank
00:03:22 --> 00:03:25 you guys for your inspiring podcast.
00:03:25 --> 00:03:27 Bye-bye. These are fantastic questions
00:03:27 --> 00:03:30 from Adriano. Really, you know, on on
00:03:30 --> 00:03:32 the edge of our knowledge really. And
00:03:32 --> 00:03:36 it's a good question. How? So, LIGO uh
00:03:36 --> 00:03:38 as you said, the laser interferometer
00:03:38 --> 00:03:41 gravitational wave observatory
00:03:41 --> 00:03:43 uh is one of several gravitational wave
00:03:43 --> 00:03:46 observatories. Now, LIGO was the first
00:03:46 --> 00:03:48 to actually detect gravitational waves
00:03:48 --> 00:03:50 back in 2015.
00:03:50 --> 00:03:56 Uh and what we saw was so gravitational
00:03:56 --> 00:03:58 waves are formed by vibrations in space
00:03:58 --> 00:04:02 and waves move through space uh which
00:04:02 --> 00:04:07 you know is is is they're basically uh
00:04:07 --> 00:04:09 propagated by the vibrations the waves
00:04:09 --> 00:04:11 are propagated by the vibrations of
00:04:11 --> 00:04:14 space. Uh because space is flexible.
00:04:14 --> 00:04:17 It's uh 100 billion billion times more
00:04:17 --> 00:04:19 rigid than steel but it's still
00:04:19 --> 00:04:24 flexible. So uh what we have is this uh
00:04:24 --> 00:04:27 phenomenon where we can actually measure
00:04:27 --> 00:04:29 those vibrations directly. And it turns
00:04:29 --> 00:04:34 out that LIGO is uh sensitive to
00:04:34 --> 00:04:37 gravitational waves with the same sort
00:04:37 --> 00:04:40 of frequency as the audio waves that we
00:04:40 --> 00:04:44 hear through our ears. Uh so audio waves
00:04:44 --> 00:04:47 are frequencies of a few hundred khertz
00:04:47 --> 00:04:50 and the gravitational waves that LIGO is
00:04:50 --> 00:04:52 sensitive to are the same. And when you
00:04:52 --> 00:04:55 look at the traces of these waves, you
00:04:55 --> 00:04:58 can see them in great detail and measure
00:04:58 --> 00:05:01 the way they change as two black holes
00:05:02 --> 00:05:04 or neutron stars combined together. Uh
00:05:04 --> 00:05:06 because there's a characteristic signal.
00:05:06 --> 00:05:08 It's called the chirp. I'll I'll do one
00:05:08 --> 00:05:10 for you, Heidi. Uh because I haven't
00:05:10 --> 00:05:13 chirped to you before. Uh if you listen
00:05:13 --> 00:05:16 to the audio, it sounds like
00:05:16 --> 00:05:19 uh and the chirp at the end is when the
00:05:20 --> 00:05:22 gravitational waves, sorry, the black
00:05:22 --> 00:05:23 holes actually emerge. They come
00:05:23 --> 00:05:25 together. Uh and it's the way that
00:05:25 --> 00:05:28 signal changes over those few tens of
00:05:28 --> 00:05:31 seconds uh at the end of their lives
00:05:31 --> 00:05:34 that let you model exactly what it is
00:05:34 --> 00:05:36 that is coming together. you can model
00:05:36 --> 00:05:40 the the objects that are colliding by
00:05:40 --> 00:05:42 analyzing that waveform in detail. So
00:05:42 --> 00:05:43 that's how it's
00:05:43 --> 00:05:45 done.
00:05:45 --> 00:05:48 Uh you don't look as though you believe
00:05:48 --> 00:05:53 me there. I uh I just think uh um Adria
00:05:53 --> 00:05:55 um Adriana's question was a little bit
00:05:55 --> 00:05:57 over my um
00:05:57 --> 00:06:00 IQ um or at least my knowledge base. But
00:06:00 --> 00:06:04 this sounds very fantastic and I'm very
00:06:04 --> 00:06:05 excited for all the people who
00:06:05 --> 00:06:10 understood um Fred's explanation. Let's
00:06:10 --> 00:06:12 go to just finish off his his other
00:06:12 --> 00:06:14 question though because that's really
00:06:14 --> 00:06:17 interesting. He he says with a bigger
00:06:17 --> 00:06:20 interpherometer could you detect the big
00:06:20 --> 00:06:25 bang and the answer is uh basically no.
00:06:25 --> 00:06:27 You need something quite different. So
00:06:27 --> 00:06:30 as I said the the LIGO and its ilk are
00:06:30 --> 00:06:34 sensitive to gravitational waves with um
00:06:34 --> 00:06:37 kilohertz frequencies. So a few a few
00:06:37 --> 00:06:40 hundred uh cycles per second as we used
00:06:40 --> 00:06:42 to call it.
00:06:42 --> 00:06:44 Uh, did I say kilohertz? Yes, I meant
00:06:44 --> 00:06:48 the wrong. Well, I'm talking. Yeah,
00:06:48 --> 00:06:50 kilhertz are a bit high. It's hundreds
00:06:50 --> 00:06:52 of hertz rather than kilohertz. So, you
00:06:52 --> 00:06:55 know, 500 600 htz, kilohertz is a
00:06:55 --> 00:06:58 thousand obviously. So, just replay that
00:06:58 --> 00:07:01 bit. Anyway, um the bottom line is to
00:07:02 --> 00:07:03 look for phenomena in the early
00:07:03 --> 00:07:05 universe. And it's not so much the big
00:07:05 --> 00:07:07 bang itself as the inflationary period
00:07:07 --> 00:07:09 that followed it when the universe
00:07:09 --> 00:07:13 expanded by 10 ^ 50 and 10 the minus 33
00:07:13 --> 00:07:16 of a second. Uh which is just beggars
00:07:16 --> 00:07:19 the imagination. But for to pick up
00:07:19 --> 00:07:22 phenomena like that you need uh you need
00:07:22 --> 00:07:26 to be sensitive to gravitational waves
00:07:26 --> 00:07:30 with nanoertz frequencies. That means
00:07:30 --> 00:07:34 um how can I put it? uh a billionth of a
00:07:34 --> 00:07:37 of a a billionth of a cycle per second.
00:07:37 --> 00:07:39 In other words, they make one cycle over
00:07:39 --> 00:07:42 a very long period of time, years,
00:07:42 --> 00:07:44 decades, maybe even millions of years
00:07:44 --> 00:07:46 with some of them. So you you never see
00:07:46 --> 00:07:49 the vibrations. You just see part of one
00:07:49 --> 00:07:51 cycle because it's so slow. The period
00:07:51 --> 00:07:54 of these vibrations is so slow. And so
00:07:54 --> 00:07:56 you need different technologies to do
00:07:56 --> 00:07:58 that. And people are working on those.
00:07:58 --> 00:08:01 And indeed, we've spoken about some on
00:08:01 --> 00:08:04 Space Nuts in the past. Yeah. People
00:08:04 --> 00:08:06 just like people just like you. I'd say
00:08:06 --> 00:08:08 people like you and me, but probably a
00:08:08 --> 00:08:12 little bit more people like you.
00:08:12 --> 00:08:15 Let's take a short break from Space Nuts
00:08:15 --> 00:08:17 to tell you about our sponsor,
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00:09:39 --> 00:09:41 nordvpn.com/spacenuts. All right, let's
00:09:41 --> 00:09:43 get back to the show.
00:09:43 --> 00:09:47 And I feel space nuts. Um our our next
00:09:47 --> 00:09:48 question is actually from your side of
00:09:48 --> 00:09:52 the world and it uh it's from an um
00:09:52 --> 00:09:55 Anthony love the show of course my
00:09:55 --> 00:09:57 question is even though the moon's orbit
00:09:57 --> 00:10:01 is tilted relative to the earth only by
00:10:01 --> 00:10:04 se or sorry by only 7° why does it
00:10:04 --> 00:10:07 appear to shift so much in the sky
00:10:07 --> 00:10:09 tonight for example it is really low in
00:10:10 --> 00:10:12 the north from my location in Sydney but
00:10:12 --> 00:10:14 at other times sometimes not too far
00:10:14 --> 00:10:17 apart it is almost overhead. It must be
00:10:17 --> 00:10:19 simple geometry, but the differences
00:10:19 --> 00:10:22 seem far too great to be 7 or 14°. It
00:10:22 --> 00:10:25 seems like much more than 45°. Certainly
00:10:25 --> 00:10:28 more than the first three lengths.
00:10:28 --> 00:10:31 Thanks. And that's from uh Anthony from
00:10:31 --> 00:10:33 Sydney, Australia. Yeah, he's probably
00:10:33 --> 00:10:36 not very far from where I'm sitting now.
00:10:36 --> 00:10:39 Hello, Anthony. So, 7 to 7 to 14 degrees
00:10:39 --> 00:10:43 away from you. Yes, it could be. Uh so
00:10:43 --> 00:10:46 actually it's 5° not 7°. Uh the tilt of
00:10:46 --> 00:10:50 the moon's orbit is 5° but
00:10:50 --> 00:10:53 uh the main point is that it's tilt that
00:10:53 --> 00:10:57 5° is with respect to the ecliptic uh
00:10:57 --> 00:10:59 which is the plane of the earth's orbit
00:10:59 --> 00:11:01 in space. So
00:11:01 --> 00:11:03 uh and and in the sky the ecliptic is
00:11:03 --> 00:11:07 the path of the sun through the sky. So
00:11:07 --> 00:11:12 uh 5° tilt to the ecliptic uh means that
00:11:12 --> 00:11:15 effectively the moon follows the sun's
00:11:15 --> 00:11:17 path through the sky with a bit of 5
00:11:17 --> 00:11:21 degrees either side of it. So is as as
00:11:21 --> 00:11:23 Anthony says that's not very much but
00:11:23 --> 00:11:25 the bottom line is of course the sun's
00:11:25 --> 00:11:27 path through the sky is tilted at 23 and
00:11:27 --> 00:11:30 a half degrees with respect to the
00:11:30 --> 00:11:34 equator and that's why um we see such
00:11:34 --> 00:11:35 large variations. So if you think about
00:11:35 --> 00:11:39 what the sun does in a year, the moon
00:11:39 --> 00:11:41 does more or less the same thing in a
00:11:42 --> 00:11:44 month because it goes around the
00:11:44 --> 00:11:46 ecliptic, 5 degrees one side or the
00:11:46 --> 00:11:48 other of it, but more or less going
00:11:48 --> 00:11:50 around the ecliptic in one month, which
00:11:50 --> 00:11:52 is why over very short periods of time
00:11:52 --> 00:11:55 you see the moon in very very diff
00:11:55 --> 00:11:58 uh in the sky. Um, one little
00:11:58 --> 00:12:00 characteristic, and this might
00:12:00 --> 00:12:03 illuminate one of the comments that, um,
00:12:03 --> 00:12:07 uh, Anthony made, is that when you're
00:12:07 --> 00:12:10 near the solstesses, either the summer
00:12:10 --> 00:12:12 solstice, which for us in Australia, uh,
00:12:12 --> 00:12:15 is in December, the sun is at its
00:12:15 --> 00:12:17 highest in the sky, uh, or the winter
00:12:17 --> 00:12:19 solstice, which for us in Australia is
00:12:19 --> 00:12:22 June. Um then the moon in its path
00:12:22 --> 00:12:25 through the sky basically uh when it's
00:12:25 --> 00:12:28 full a full moon is exactly opposite
00:12:28 --> 00:12:30 where the sun is. So when the sun's very
00:12:30 --> 00:12:32 high in the sky a full moon is very low
00:12:32 --> 00:12:35 in the sky. It's right opposite it with
00:12:35 --> 00:12:38 within five degrees either side. Uh so I
00:12:38 --> 00:12:40 always think of that when I look at a
00:12:40 --> 00:12:43 full moon um I imagine it's where the
00:12:43 --> 00:12:46 sun will be in six months time uh at the
00:12:46 --> 00:12:49 different time of year which is kind of
00:12:49 --> 00:12:51 quite cute really in a peculiar sort of
00:12:51 --> 00:12:55 way. Um so yes it's a good observation
00:12:55 --> 00:12:56 uh but the reason for it is as you said
00:12:56 --> 00:12:58 it's geometry.
00:12:58 --> 00:13:01 I uh I I never thought of that. That's a
00:13:01 --> 00:13:04 that's a quite a cool little tidbit. I'm
00:13:04 --> 00:13:05 just I'm thinking back, this is a little
00:13:05 --> 00:13:07 bit of a a side story, but I got
00:13:07 --> 00:13:09 married. I insisted I told my husband I
00:13:09 --> 00:13:11 wanted to do an astronomy kind of themed
00:13:11 --> 00:13:13 wedding. And so we got married under we
00:13:13 --> 00:13:15 chose the October full moon, the
00:13:15 --> 00:13:18 hunter's moon, and we got married and
00:13:18 --> 00:13:20 then we immediately um the next day we
00:13:20 --> 00:13:22 were driving across the country because
00:13:22 --> 00:13:24 I was from Utah, he was in Florida at
00:13:24 --> 00:13:25 the time. So we started our road trip to
00:13:26 --> 00:13:27 Florida the day after we got married.
00:13:27 --> 00:13:29 And I just remember um because we did
00:13:30 --> 00:13:31 our our our full moon wedding and I got
00:13:31 --> 00:13:33 married right at the time that the moon
00:13:33 --> 00:13:35 was supposed to be at its fullest. I'm a
00:13:35 --> 00:13:36 little bit of a weirdo. But then the
00:13:36 --> 00:13:40 next day the moon was so low in the sky
00:13:40 --> 00:13:42 and bright red. I just remember it was
00:13:42 --> 00:13:44 the most brilliant looking thing I've
00:13:44 --> 00:13:46 ever seen. And so just really kind of
00:13:46 --> 00:13:48 thinking about Antony's question with
00:13:48 --> 00:13:49 you know when we got married it was up
00:13:49 --> 00:13:51 in the sky and then the very next day
00:13:51 --> 00:13:53 it's right down low on the horizon like
00:13:53 --> 00:13:55 a movie. It was like a like like almost
00:13:55 --> 00:13:58 like a Lawrence of Arabia type kind of
00:13:58 --> 00:14:01 uh look. It was very cool. Um Heidi, I'm
00:14:01 --> 00:14:03 going to pick up on that today because I
00:14:03 --> 00:14:06 can't resist this. Many and I too had a
00:14:06 --> 00:14:09 an an astronomical wedding.
00:14:09 --> 00:14:12 We got married. Uh and this is why I'm
00:14:12 --> 00:14:14 picking up on this. Uh six years ago
00:14:14 --> 00:14:17 today, it's actually today is our
00:14:17 --> 00:14:20 anniversary. Oh, happy anniversary.
00:14:20 --> 00:14:21 Thank you very much. Yeah, we we've been
00:14:21 --> 00:14:23 together for nearly 20 years, but it
00:14:23 --> 00:14:25 took us quite a while to get married. Uh
00:14:26 --> 00:14:28 six years ago today, we got married on
00:14:28 --> 00:14:31 the summit of Halakala on Maui, which
00:14:31 --> 00:14:34 has uh a number of large significant
00:14:34 --> 00:14:37 telescopes on it, including Pan Stars 2,
00:14:37 --> 00:14:40 the asteroid guardian telescope uh and
00:14:40 --> 00:14:43 the Daniel Kui uh solar telescope, the
00:14:43 --> 00:14:44 biggest solar telescope in the world.
00:14:44 --> 00:14:46 They were right behind us when we got
00:14:46 --> 00:14:49 married at 10 ft on the summit of
00:14:49 --> 00:14:51 Maui. and I got wonderfully sunburned on
00:14:51 --> 00:14:54 the top of my head.
00:14:54 --> 00:14:56 Oh, that's such a beautiful story. Well,
00:14:56 --> 00:14:59 congrats to you and congrats to Congrats
00:14:59 --> 00:15:01 to yours. And that's a that's such a
00:15:01 --> 00:15:02 beautiful story. I guess we're
00:15:02 --> 00:15:05 dedicating this episode to um our our
00:15:06 --> 00:15:08 significant others and the That's right.
00:15:08 --> 00:15:11 Yeah. And the moon. That's right. Yeah.
00:15:12 --> 00:15:13 Sorry. Sorry to hijack that
00:15:13 --> 00:15:15 conversation. Oh, no. That was uh that
00:15:15 --> 00:15:16 was well that was a fun you know maybe
00:15:16 --> 00:15:19 maybe people are curious about your um
00:15:19 --> 00:15:21 you know your personal personal um
00:15:21 --> 00:15:23 experiences with space cuz I think you
00:15:23 --> 00:15:25 know sometimes it's nice to add in
00:15:25 --> 00:15:27 infuse a little bit of the personal love
00:15:27 --> 00:15:31 for space too.
00:15:31 --> 00:15:34 Okay we checked all four systems with
00:15:34 --> 00:15:37 space nets. Um our next uh question is
00:15:37 --> 00:15:41 an audio question and this is Mikey from
00:15:41 --> 00:15:44 Illinois USA. Hey friend Andrew. This is
00:15:44 --> 00:15:46 Mikey once again from Illinois in the US
00:15:46 --> 00:15:49 of A. I'm just wondering if you guys
00:15:49 --> 00:15:51 have any room in your house for me and
00:15:51 --> 00:15:54 my family. I'm just kid unless you're
00:15:54 --> 00:15:56 serious. I'm just joking. Unless you
00:15:56 --> 00:15:59 want me to. I'm just kidding. Keep it in
00:15:59 --> 00:16:04 mind. Um so I know that space can bend.
00:16:04 --> 00:16:07 Uh space can warp. Space can ripple.
00:16:07 --> 00:16:10 Space can supposedly tear.
00:16:10 --> 00:16:13 I was curious as to what it means for
00:16:13 --> 00:16:15 space to actually tear. Like, have we
00:16:16 --> 00:16:17 seen
00:16:17 --> 00:16:20 examples in real life of space tearing
00:16:20 --> 00:16:22 and what would that look like or is it
00:16:22 --> 00:16:24 just we know it can but we haven't seen
00:16:24 --> 00:16:26 it? Um, yeah, I was just hoping you guys
00:16:26 --> 00:16:28 could explain that a little bit more.
00:16:28 --> 00:16:30 Appreciate you guys. Love the show. What
00:16:30 --> 00:16:33 a what an interesting question. Um, and
00:16:33 --> 00:16:36 it's it it it it is
00:16:36 --> 00:16:39 hypothetical the idea of space tearing
00:16:39 --> 00:16:42 uh because we've never ever seen
00:16:42 --> 00:16:44 anything symptomatic of tearing space
00:16:44 --> 00:16:47 either here on our planet or in the
00:16:47 --> 00:16:50 wider universe and it would have to be
00:16:50 --> 00:16:52 under very very extreme circumstances
00:16:52 --> 00:16:57 that it would happen. Um so uh by
00:16:57 --> 00:16:59 extreme I mean space being stretched
00:16:59 --> 00:17:00 beyond its
00:17:00 --> 00:17:03 limits. And the reason why this is a
00:17:03 --> 00:17:06 popular notion is because of the
00:17:06 --> 00:17:12 discovery back in uh back in 1998
00:17:12 --> 00:17:17 uh that space is ex accelerating in its
00:17:17 --> 00:17:19 expansion. We've known since 1929 that
00:17:19 --> 00:17:21 the universe is expanding. That's taking
00:17:22 --> 00:17:24 space with it. Uh but since 1998, we've
00:17:24 --> 00:17:27 known that that expansion has been ever
00:17:27 --> 00:17:29 faster, ever more rapid. It's
00:17:29 --> 00:17:32 accelerating. Uh and so that's given
00:17:32 --> 00:17:35 rise to the idea of if this goes on into
00:17:35 --> 00:17:37 the far distant future, are we going to
00:17:37 --> 00:17:40 get to a situation where space is so
00:17:40 --> 00:17:43 stretched that it falls apart? Uh and
00:17:43 --> 00:17:47 that gives rise to the notion of uh the
00:17:47 --> 00:17:50 big rip. And actually the the best place
00:17:50 --> 00:17:53 I can direct Mikey to on the web because
00:17:53 --> 00:17:56 it's explained very um I won't say
00:17:56 --> 00:17:58 concisely, it's explored in great
00:17:58 --> 00:18:01 detail, but it's quite easy to read. Uh
00:18:01 --> 00:18:06 is the big rip uh entry on Wikipedia. Uh
00:18:06 --> 00:18:09 I'm a big fan of Wikipedia. Uh and the
00:18:09 --> 00:18:11 big rip entry is really quite
00:18:11 --> 00:18:14 extraordinary because it talks about the
00:18:14 --> 00:18:17 hypothesis that space could tear. It
00:18:17 --> 00:18:20 talks a little bit about the work that's
00:18:20 --> 00:18:22 been done on this, the research that has
00:18:22 --> 00:18:25 been carried out in a in a serious um
00:18:25 --> 00:18:28 you know academic manner as to what
00:18:28 --> 00:18:29 might constitute space being ripped
00:18:30 --> 00:18:34 apart. Uh and you can you can sort of
00:18:34 --> 00:18:36 define that in terms of the various
00:18:36 --> 00:18:39 fundamental forces of nature and um
00:18:40 --> 00:18:42 there is a hypothesis that then suggests
00:18:42 --> 00:18:44 what that what might be the trigger for
00:18:44 --> 00:18:47 a big rip in terms of you know the
00:18:47 --> 00:18:49 tension that is involved.
00:18:49 --> 00:18:52 uh and that one of the authors of that
00:18:52 --> 00:18:54 hypothesis is Robert Caldwell of
00:18:54 --> 00:18:56 Dartmouth College who presents us with a
00:18:56 --> 00:18:59 formula which defines when the big rip
00:18:59 --> 00:19:02 will take place. Uh it's quite a neat
00:19:02 --> 00:19:03 formula. It includes things like the
00:19:03 --> 00:19:06 Hubble constant and the barionic mass
00:19:06 --> 00:19:08 content of the universe. It's all there
00:19:08 --> 00:19:10 on the page. Uh and I think the bottom
00:19:10 --> 00:19:13 line is uh is it 20 billion years? I
00:19:13 --> 00:19:14 think something like that. Oh no, wait a
00:19:14 --> 00:19:17 minute. The earliest is 152 billion
00:19:17 --> 00:19:19 years time. That's when space we've got
00:19:19 --> 00:19:22 time. Yeah. 152 billion years. Put it in
00:19:22 --> 00:19:24 your diary, Mikey, because that's when
00:19:24 --> 00:19:27 you will find the first example of space
00:19:27 --> 00:19:31 being ripped. Oh my. Well, our very last
00:19:31 --> 00:19:33 question is um from from my side of the
00:19:33 --> 00:19:36 world again. So, we got Greg from
00:19:36 --> 00:19:39 Minnesota. So, he says, "Hello from
00:19:39 --> 00:19:41 Minnesota, USA. I'm Greg and I have a
00:19:41 --> 00:19:45 question about the cosmic jerk. And no,
00:19:45 --> 00:19:47 I don't mean Fred.
00:19:48 --> 00:19:51 Oh, Fred. Uh, and his question is, the
00:19:51 --> 00:19:53 change of position over time is
00:19:53 --> 00:19:56 velocity, and the change of velocity
00:19:56 --> 00:19:59 over time is acceleration. But we don't
00:19:59 --> 00:20:01 need to stop there. The change of
00:20:01 --> 00:20:04 acceleration over time is called jerk.
00:20:04 --> 00:20:07 We know the universe is accelerating,
00:20:07 --> 00:20:09 but but have we been able to measure
00:20:10 --> 00:20:12 whether or not it's accelerating at a
00:20:12 --> 00:20:15 constant rate? Love the podcast. Keep up
00:20:15 --> 00:20:18 the good work. If you're curious, the
00:20:18 --> 00:20:20 next derivatives after jerk are snap,
00:20:20 --> 00:20:24 snap, crackle, and pop.
00:20:24 --> 00:20:27 Yeah. So, um I'll I'll refrain from
00:20:27 --> 00:20:29 using the term jerk since it's been
00:20:29 --> 00:20:33 applied to me. Um and give it its proper
00:20:33 --> 00:20:36 name, which is uh the rate of change of
00:20:36 --> 00:20:38 acceleration. So, acceleration is the
00:20:38 --> 00:20:40 rate of change of velocity. Velocity is
00:20:40 --> 00:20:42 the rate of change of position as
00:20:42 --> 00:20:44 exactly as as Greg says. I was uh
00:20:44 --> 00:20:45 thinking this question was going to be
00:20:46 --> 00:20:47 for me for a second. I was like, "Wait a
00:20:47 --> 00:20:48 second. That's what I do my research
00:20:48 --> 00:20:50 in."
00:20:50 --> 00:20:55 Yes. So, yeah. So, so um but but but
00:20:55 --> 00:20:59 Greg's question is is very very uh
00:20:59 --> 00:21:01 topical at the moment because yes, we've
00:21:01 --> 00:21:03 known that the universe is accelerating
00:21:03 --> 00:21:05 as I said a few minutes ago since 1998.
00:21:05 --> 00:21:09 Discovery made by an Australian and a a
00:21:09 --> 00:21:12 US scientist in working independently.
00:21:12 --> 00:21:16 Um that discovery immediately led to the
00:21:16 --> 00:21:19 question is the acceleration changing in
00:21:19 --> 00:21:21 other words is there a rate of change of
00:21:21 --> 00:21:24 acceleration and that's a very hard uh
00:21:24 --> 00:21:27 observation to make um you need to look
00:21:28 --> 00:21:31 at the universe over the widest possible
00:21:31 --> 00:21:33 range of look back times. So you want to
00:21:33 --> 00:21:36 look back 11 billion years if you can uh
00:21:36 --> 00:21:38 you know sort of 78 of the age of the
00:21:38 --> 00:21:42 universe. uh and so what's happened uh
00:21:42 --> 00:21:45 recently is u uh something called uh
00:21:45 --> 00:21:47 DESI which is the dark energy survey
00:21:47 --> 00:21:49 instrument and dark energy is by the way
00:21:50 --> 00:21:51 the mechanism which we think is causing
00:21:52 --> 00:21:54 the universe to expand that space has an
00:21:54 --> 00:21:57 energy of its own until now we've
00:21:57 --> 00:21:59 believed that was a constant that the
00:21:59 --> 00:22:01 acceleration of the universe was a
00:22:01 --> 00:22:05 constant but DESI the dark energy survey
00:22:05 --> 00:22:09 instrument on a telescope uh in Arizona
00:22:09 --> 00:22:11 based on the male telescope, the 4 meter
00:22:11 --> 00:22:14 telescope at Kick Peak. Uh that seems to
00:22:14 --> 00:22:17 be indicating and it's still not
00:22:17 --> 00:22:20 speculative. It's still u um you know
00:22:20 --> 00:22:23 one of these results that's still got a
00:22:23 --> 00:22:25 question mark over it, but it seems to
00:22:25 --> 00:22:26 indicate that the acceleration is
00:22:26 --> 00:22:28 slowing down. And slowing down the
00:22:28 --> 00:22:31 acceleration is a good thing because it
00:22:31 --> 00:22:35 might put off the big rip beyond 152
00:22:35 --> 00:22:37 billion years. might push it back into
00:22:37 --> 00:22:41 the more distant horizon. Uh so we will
00:22:41 --> 00:22:43 it remains to be seen. Uh but I think
00:22:43 --> 00:22:45 the odds are that over the next few
00:22:45 --> 00:22:47 years we'll find compelling evidence
00:22:47 --> 00:22:50 that the acceleration of the universe's
00:22:50 --> 00:22:53 expansion is slowing down. And that's a
00:22:53 --> 00:22:55 mystery because that needs a mechanism
00:22:55 --> 00:22:57 and it probably suggests there are new
00:22:57 --> 00:23:00 physics that we do not understand uh
00:23:00 --> 00:23:02 that have yet to be determined and it
00:23:02 --> 00:23:05 opens up all kinds of areas of research
00:23:05 --> 00:23:07 uh which seems like a really good way to
00:23:07 --> 00:23:11 wrap up this Q&A session of Space Nut.
00:23:11 --> 00:23:14 Absolutely. And um and I'm and um I'll
00:23:14 --> 00:23:17 I'll tie that in with uh love, another
00:23:17 --> 00:23:19 one of life's greatest mysteries. Uh,
00:23:19 --> 00:23:21 since we're talking about our our loved
00:23:21 --> 00:23:23 ones, if there is somebody that you love
00:23:24 --> 00:23:26 and you would love to share this podcast
00:23:26 --> 00:23:29 with, we would be just tickled if you
00:23:29 --> 00:23:31 could tell everybody that you love and
00:23:31 --> 00:23:33 maybe some people that you don't even
00:23:33 --> 00:23:34 really care for, but you sit next to
00:23:34 --> 00:23:36 them at the office. Uh, tell your
00:23:36 --> 00:23:38 friends, tell your family, tell the
00:23:38 --> 00:23:40 people you don't like, tell your dog,
00:23:40 --> 00:23:42 tell your cat um about Space Nuts. We
00:23:42 --> 00:23:45 are here for you. We've got our uh
00:23:45 --> 00:23:48 question and answer episodes and our
00:23:48 --> 00:23:50 more I guess uh what do we call this?
00:23:50 --> 00:23:52 More narrative story style episodes
00:23:52 --> 00:23:55 every week. And so Fred, do you have
00:23:55 --> 00:23:56 anything else you want to add before we
00:23:56 --> 00:23:59 sign off for the day? I think we've
00:23:59 --> 00:24:01 covered uh so much of the big mysteries
00:24:02 --> 00:24:03 today that we should just go away with
00:24:03 --> 00:24:05 our heads spinning and try and think of
00:24:05 --> 00:24:07 some more questions for next time.
00:24:07 --> 00:24:09 Excellent. Well, hey Fred, thank you so
00:24:09 --> 00:24:12 much. This has been another episode of
00:24:12 --> 00:24:14 Space Nut. Space Nuts. You'll be
00:24:14 --> 00:24:18 listening to the Space Nuts podcast
00:24:18 --> 00:24:21 available at Apple Podcasts, Spotify,
00:24:21 --> 00:24:23 iHeart Radio, or your favorite podcast
00:24:24 --> 00:24:26 player. You can also stream on demand at
00:24:26 --> 00:24:29 byes.com. This has been another quality
00:24:29 --> 00:24:33 podcast production from byes.com.