In this thought-provoking episode of Space Nuts, hosts Andrew Dunkley and Professor Jonti Horner tackle a range of intriguing listener questions. From the complexities of climate change and its effects on Earth’s axis to the mysteries of snowball Earth and the record-breaking neutrino KM M3230213A, this episode is packed with cosmic insights and scientific discussion.
Episode Highlights:
- Climate Change Explained: Andrew and Jonti address Peter's question on how CO2, despite being heavier than air, contributes to global warming. They discuss the greenhouse effect and the role of carbon dioxide in trapping heat, along with the challenges of public perception regarding climate science.
- Snowball Earth Insights: Paul’s inquiry leads to an exploration of the snowball Earth hypothesis, examining how such extreme climate conditions could affect oxygen levels and what triggers these dramatic shifts in Earth’s climate.
- Cosmic Neutrinos Unveiled: Casey’s question about the record-breaking KM M3230213A neutrino sparks a fascinating discussion on its origins, possible sources, and the implications of detecting such high-energy particles from the early universe.
- Understanding MWC349A: Henrique asks about the mysterious object MWC349A and its unique emissions. The hosts delve into the science of masers and the significance of this object in understanding stellar evolution and mass loss.
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 favourite platform.
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Stay curious, keep looking up, and join us next time for more stellar insights and cosmic wonders. Until then, clear skies and happy stargazing.
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00:00:00 --> 00:00:02 Andrew Dunkley: Hi there. Thanks for joining us on a Q and A
00:00:02 --> 00:00:05 edition of Space Nuts. My name is Andrew
00:00:05 --> 00:00:07 Dunkley and this is the. The show we do each
00:00:07 --> 00:00:10 week where you supply the agenda
00:00:10 --> 00:00:12 and we pretend we know what we're talking
00:00:12 --> 00:00:15 about. And questions are coming in,
00:00:15 --> 00:00:18 uh, for this week's show from Peter, who's
00:00:18 --> 00:00:20 asking about climate change.
00:00:21 --> 00:00:22 Jonti Horner: Paul is.
00:00:22 --> 00:00:24 Andrew Dunkley: Well, I suppose it's a similar story.
00:00:24 --> 00:00:27 Snowball, uh, Earth and, uh, a couple of
00:00:27 --> 00:00:29 objects of interest. Uh, Casey is asking
00:00:29 --> 00:00:30 about KM
00:00:30 --> 00:00:33 M3230213A.
00:00:33 --> 00:00:36 Know all about it. And an even more obscure
00:00:36 --> 00:00:38 thing. Henrik has asked about
00:00:39 --> 00:00:42 MWC3498, which I just did a
00:00:42 --> 00:00:44 Google search for and it came up blank.
00:00:46 --> 00:00:49 Anyway, it's an A at the end, not an A. I had
00:00:49 --> 00:00:51 fun with that. Ah, is that the one? All
00:00:51 --> 00:00:53 right. And that's what we're talking about
00:00:53 --> 00:00:55 with that little voice you just heard in the
00:00:55 --> 00:00:57 background on this edition of space
00:00:57 --> 00:00:58 nuts.
00:00:58 --> 00:01:01 Voice Over Guy: 15 seconds. Guidance is internal.
00:01:01 --> 00:01:04 10, 9. Ignition
00:01:04 --> 00:01:06 sequence start. Space nuts. 5, 4, 3,
00:01:07 --> 00:01:09 2. 1. 2, 3, 4, 5, 5, 4,
00:01:09 --> 00:01:12 3, 2, 1. Space nuts. Astronauts
00:01:12 --> 00:01:14 report it feels good.
00:01:14 --> 00:01:17 Andrew Dunkley: And that voice belongs to none other than
00:01:17 --> 00:01:19 Professor Jonti T. Horner, professor of
00:01:19 --> 00:01:22 Astrophysics at the University of Southern
00:01:22 --> 00:01:23 Queensland, Jonti. Hello again.
00:01:24 --> 00:01:25 Jonti Horner: Good afternoon. Yeah, clearly professor of
00:01:25 --> 00:01:27 interruptions. This is what happens when I've
00:01:27 --> 00:01:29 had enough time for the coffee to kick in.
00:01:29 --> 00:01:32 Andrew Dunkley: Uh, yes, it's been, um, what, four
00:01:32 --> 00:01:34 days and we're still wearing the same
00:01:34 --> 00:01:34 clothes.
00:01:34 --> 00:01:35 Jonti Horner: Absolutely.
00:01:35 --> 00:01:37 Andrew Dunkley: Yeah, I get a lot of mileage out of that
00:01:37 --> 00:01:39 joke. Yeah.
00:01:39 --> 00:01:40 Jonti Horner: Um, but you've been done.
00:01:40 --> 00:01:42 Had a musical interlude. Haven't I have.
00:01:42 --> 00:01:43 Andrew Dunkley: Look, I, um.
00:01:44 --> 00:01:45 Jonti Horner: It.
00:01:45 --> 00:01:47 Andrew Dunkley: It was just. Last weekend was a long weekend,
00:01:47 --> 00:01:50 uh, in New South Wales, and I think it was in
00:01:50 --> 00:01:52 Queensland too. But, um, it was the weekend
00:01:52 --> 00:01:55 that Taylor Swift released her latest
00:01:55 --> 00:01:58 album. And, uh,
00:01:58 --> 00:02:01 I've got three granddaughters, all of
00:02:01 --> 00:02:03 Taylor's swifty age. And
00:02:03 --> 00:02:06 uh, we. Yeah, we took them to see
00:02:06 --> 00:02:09 the launch of her new album. Uh, and,
00:02:10 --> 00:02:12 uh, I. Look, I've got to tell you, I really
00:02:12 --> 00:02:14 did, I did. I enjoy it.
00:02:15 --> 00:02:18 Yes. It's not aimed at
00:02:18 --> 00:02:20 me or my demographic, but, um,
00:02:20 --> 00:02:23 it was, uh, it was interesting to
00:02:23 --> 00:02:26 watch some of the thinking behind the artist
00:02:26 --> 00:02:28 and some of the creativity that went into
00:02:28 --> 00:02:31 film clips and things like that. That's the,
00:02:31 --> 00:02:33 that's what I got out of it. But what, uh, an
00:02:33 --> 00:02:33 extraordinary.
00:02:34 --> 00:02:35 Jonti Horner: It's one of the things I love.
00:02:35 --> 00:02:37 I know we've gone totally off topic straight
00:02:37 --> 00:02:40 away, but my favorite critic, and the kind of
00:02:40 --> 00:02:42 only one I pay attention to, really is a guy
00:02:42 --> 00:02:44 called Mark commodity in the UK who's, um,
00:02:44 --> 00:02:46 they used to be on BBC Radio 5 live and now
00:02:46 --> 00:02:48 they've got their own independent, um, thing.
00:02:48 --> 00:02:50 And it's one of those things that's like
00:02:50 --> 00:02:51 comfort food for the soul that you can listen
00:02:51 --> 00:02:54 to and just makes your children relax. But
00:02:54 --> 00:02:56 part of what's nice about him is that you get
00:02:56 --> 00:02:58 a lot of film critics who, if a film's not
00:02:58 --> 00:03:00 made for them, are in some misdiabos about
00:03:00 --> 00:03:03 it. Right. And you know, I remember this with
00:03:03 --> 00:03:04 the Twilight films, which I'm not the target
00:03:04 --> 00:03:06 audience, they're not my cup of tea, but they
00:03:06 --> 00:03:09 got panned because they're made for
00:03:09 --> 00:03:11 teenage girls and film critics are elderly
00:03:11 --> 00:03:12 men and there's a slightly different
00:03:12 --> 00:03:15 demographic there. And this guy's brilliant
00:03:15 --> 00:03:16 because he'll m. Make the point. You know,
00:03:16 --> 00:03:18 I'm not the target audience for this. I'm
00:03:18 --> 00:03:21 very clearly not it and I enjoyed it. Okay.
00:03:21 --> 00:03:22 But you look around the room at the people
00:03:22 --> 00:03:24 who are the target audience and they love it.
00:03:24 --> 00:03:26 So it's obviously doing well. I think it's
00:03:26 --> 00:03:28 the same with what you're saying by the
00:03:28 --> 00:03:29 Taylor Swift stuff. We're not the target
00:03:29 --> 00:03:31 audience. But you can appreciate that this is
00:03:31 --> 00:03:34 someone who's awesomely talented and ah, for
00:03:34 --> 00:03:35 the target audience, it's really
00:03:35 --> 00:03:37 fundamentally awesome, you know.
00:03:38 --> 00:03:40 Andrew Dunkley: Yeah. Uh, I was still working on
00:03:40 --> 00:03:43 radio, uh, when she was, uh,
00:03:43 --> 00:03:45 announced by Time magazine as Person of the
00:03:45 --> 00:03:48 Year. And I did a big, big
00:03:48 --> 00:03:51 statement at the time as far as I was
00:03:51 --> 00:03:53 concerned, uh, about why she deserved
00:03:53 --> 00:03:56 it because she brought light into the world
00:03:57 --> 00:04:00 at a very dark time towards the end of COVID
00:04:00 --> 00:04:03 And um, but then they went
00:04:03 --> 00:04:04 and made Donaldjohanson Trump the, uh, Person
00:04:04 --> 00:04:06 of the Year. So anyway, whatever.
00:04:07 --> 00:04:09 Jonti Horner: Um, can't see the light without having
00:04:09 --> 00:04:09 darkness. Right.
00:04:10 --> 00:04:12 Andrew Dunkley: And I will say one of the songs on the new
00:04:12 --> 00:04:15 album has got to be about Donaldjohanson
00:04:15 --> 00:04:18 Trump. So anyway, he's after
00:04:18 --> 00:04:21 a Nobel priest Peace Prize and the word on
00:04:21 --> 00:04:24 the hill is that, uh, you might just get
00:04:24 --> 00:04:27 it. Uh, we won't go there. It's not
00:04:27 --> 00:04:29 our agenda. But, uh, we will go to some
00:04:29 --> 00:04:31 questions. Why don't we try and tackle this
00:04:31 --> 00:04:34 very first one? And this one
00:04:34 --> 00:04:35 comes from Peter.
00:04:35 --> 00:04:37 With all this climate change happening, I,
00:04:37 --> 00:04:40 uh, was wondering how CO2 is
00:04:40 --> 00:04:42 warming the planet when it's heavy. Heavier
00:04:42 --> 00:04:45 than air. Maybe the problem is the axis of
00:04:45 --> 00:04:47 the planet has moved because of all the
00:04:47 --> 00:04:49 millions of tons of minerals that have been
00:04:49 --> 00:04:52 moved. Maybe someone should check the
00:04:52 --> 00:04:55 axis angle. Geez, Peter, I
00:04:55 --> 00:04:57 think I've heard this theory Once before.
00:04:58 --> 00:05:00 I doubt that the amount of stuff we take out
00:05:00 --> 00:05:02 of the ground and move around the planet is
00:05:02 --> 00:05:05 going to make that big a difference
00:05:05 --> 00:05:06 to the tilt.
00:05:07 --> 00:05:09 Jonti Horner: No, and the beauty is we can measure the
00:05:09 --> 00:05:12 tilt. I mean, I grew up in the north
00:05:12 --> 00:05:14 of England, and high in the sky was
00:05:14 --> 00:05:16 Polaris, the pole star, which is the
00:05:16 --> 00:05:18 direction that the northern end of the
00:05:18 --> 00:05:21 Earth's, uh, spin axis points to. I'm very,
00:05:21 --> 00:05:23 very close to that star. So we can see
00:05:23 --> 00:05:25 exactly where the spin axis of the Earth is
00:05:25 --> 00:05:28 pointing. We can measure its spin rate. And
00:05:28 --> 00:05:31 it is right that moving material around
00:05:31 --> 00:05:34 on the Earth will to some degree change its
00:05:34 --> 00:05:36 spin and change its spin axis tilt.
00:05:37 --> 00:05:40 Um, but, and it's a very big but the amount
00:05:40 --> 00:05:43 of change that you get from human activity is
00:05:43 --> 00:05:46 very, very, very, very small. A much
00:05:46 --> 00:05:48 bigger shift in mass, for example, happens
00:05:48 --> 00:05:51 with melting of the polar caps. Yeah, if you
00:05:51 --> 00:05:53 melt the polar caps, you move the water. The
00:05:53 --> 00:05:55 water settles all around the Earth, so you're
00:05:55 --> 00:05:56 effectively moving mass from near the poles
00:05:56 --> 00:05:59 to near the equator. And that changes the
00:05:59 --> 00:06:00 Earth's rotational angular momentum and will
00:06:00 --> 00:06:03 change the Earth's spin very, very, very,
00:06:03 --> 00:06:06 very slightly. But we're now incredibly
00:06:06 --> 00:06:08 technologically capable, so we can measure
00:06:08 --> 00:06:09 things that are that small. And a good
00:06:09 --> 00:06:12 example of that was the big Indian Ocean
00:06:12 --> 00:06:14 tsunami. The earthquake that caused that, uh,
00:06:14 --> 00:06:16 on the Pacific Rim had a measurable effect on
00:06:16 --> 00:06:19 the Earth's spin. But if I remember rightly,
00:06:19 --> 00:06:21 and I stand to be corrected here, that
00:06:21 --> 00:06:24 measurable effect was something like one, one
00:06:24 --> 00:06:26 millionth of a second in the spin rate or
00:06:26 --> 00:06:27 something like that. And we can measure that,
00:06:28 --> 00:06:29 but it's not like you'd notice it in your day
00:06:29 --> 00:06:31 to day life. And it's not like that would be
00:06:31 --> 00:06:34 big enough to cause the impact on the climate
00:06:34 --> 00:06:36 that we see today. Now, I understand
00:06:37 --> 00:06:39 that, thanks to, uh, decades of
00:06:39 --> 00:06:41 discussion, that climate change is still a
00:06:41 --> 00:06:43 bit of a controversial topic with some
00:06:43 --> 00:06:46 people. And I'm quite
00:06:46 --> 00:06:48 fundamentally comfortable saying climate
00:06:48 --> 00:06:49 change is a real thing, that the climate is
00:06:49 --> 00:06:52 changing. I spent three years early in my
00:06:52 --> 00:06:55 career living in Switzerland, and when I was
00:06:55 --> 00:06:56 in Switzerland, I used to go skiing, because
00:06:56 --> 00:06:58 skiing's awesome. And if you're in
00:06:58 --> 00:07:00 Switzerland, why wouldn't you? And all these
00:07:00 --> 00:07:02 beautiful little towns that I went to in the
00:07:02 --> 00:07:03 winter, and then you went back in the summer
00:07:03 --> 00:07:05 and you went walking in the hills instead of
00:07:05 --> 00:07:07 skiing because all the snow had gone. They
00:07:07 --> 00:07:09 all have these photos from 50 or 100 years
00:07:09 --> 00:07:11 ago where you have the village in the
00:07:11 --> 00:07:13 foreground and the glacier in the background
00:07:13 --> 00:07:16 winding out of the hills. And then if you're
00:07:16 --> 00:07:17 up there in the summer, you go out and look,
00:07:17 --> 00:07:20 and it isn't there anymore. It's retreated
00:07:20 --> 00:07:22 that far. And I think that's fundamentally
00:07:22 --> 00:07:24 why in a lot of those countries with Alpine
00:07:24 --> 00:07:26 regions, climate change has been accepted for
00:07:26 --> 00:07:28 much, much longer, because you can really
00:07:28 --> 00:07:31 physically see the effects. And so it's very
00:07:31 --> 00:07:33 clear that it's happening. And the argument
00:07:33 --> 00:07:35 that it's caused by humor rather than
00:07:35 --> 00:07:37 something natural, the strongest evidence for
00:07:37 --> 00:07:39 that, to be honest, is the speed at which
00:07:39 --> 00:07:42 it's happening is unprecedented. The natural
00:07:42 --> 00:07:45 effects that could cause it, like the
00:07:45 --> 00:07:46 transition from the ice ages to the
00:07:46 --> 00:07:47 interglacials, and we'll talk about this a
00:07:47 --> 00:07:49 bit more later on, are, uh, much more
00:07:49 --> 00:07:52 gradual. Changes in brightness of the sun are
00:07:52 --> 00:07:54 much more gradual. And in fact, the sun has
00:07:54 --> 00:07:55 dimmed a little bit over the time that we've
00:07:55 --> 00:07:57 been measuring climate change due to little
00:07:57 --> 00:08:00 bits of tweaks in its behavior. So if
00:08:00 --> 00:08:02 the climate wasn't changing, we'd actually be
00:08:02 --> 00:08:04 slightly cooler now than we were a couple of
00:08:04 --> 00:08:07 hundred years ago, only very slightly. But
00:08:07 --> 00:08:08 that leads to this perverse and confusing
00:08:08 --> 00:08:11 statistic that 110% of all climate change is
00:08:11 --> 00:08:13 caused by humans because we're not just
00:08:14 --> 00:08:15 making it warmer, but we're offsetting the
00:08:15 --> 00:08:18 cooling as well. Yeah, so that's all the
00:08:18 --> 00:08:20 background to it here, how carbon dioxide
00:08:20 --> 00:08:23 plays a role. Even though it's, you know,
00:08:23 --> 00:08:25 heavier than air, it's still gas, it still
00:08:25 --> 00:08:26 floats around up there. It's not like it all
00:08:26 --> 00:08:28 sits at ankle level on the Earth. But even if
00:08:28 --> 00:08:31 it did, it would still be fairly effective
00:08:31 --> 00:08:33 because what carbon dioxide is in a really
00:08:33 --> 00:08:36 broad sense is it's like a good winter doona
00:08:36 --> 00:08:38 that you've got. The way that
00:08:39 --> 00:08:41 I can understand this as an astronomer most
00:08:41 --> 00:08:43 obviously is, uh, I think back m to again.
00:08:43 --> 00:08:45 When I was a kid, 1983, when I was five years
00:08:45 --> 00:08:47 old, there was this satellite launch called
00:08:47 --> 00:08:49 the infrared astronomical satellite IRAs.
00:08:49 --> 00:08:52 And that was really foundational for a lot of
00:08:52 --> 00:08:54 what we've learned about planets around other
00:08:54 --> 00:08:56 stars, because it was a tool that first
00:08:56 --> 00:08:59 allowed us to find debris disks around stars,
00:08:59 --> 00:09:00 which are, uh, the leftovers from planet
00:09:00 --> 00:09:03 formation. And that was a bit of a shock
00:09:03 --> 00:09:05 because stars didn't look how they were
00:09:05 --> 00:09:07 expected to. Three of them in particular.
00:09:07 --> 00:09:10 Vega, Fomalkauten, Beta Pictoris. They were
00:09:10 --> 00:09:11 brighter in the infrared wavelengths than we
00:09:11 --> 00:09:13 expected. They thought the satellite was
00:09:13 --> 00:09:15 broken. Then they realized that, no, really,
00:09:15 --> 00:09:17 the stars just had all this debris around
00:09:17 --> 00:09:19 them that was getting hot, warming up, and
00:09:19 --> 00:09:20 Giving off radiation and infrared
00:09:20 --> 00:09:23 wavelengths. So this tells us that
00:09:23 --> 00:09:26 when you heat something up, it radiates that
00:09:26 --> 00:09:28 energy away in infrared. And that's why
00:09:28 --> 00:09:30 thermal imaging cameras work. You can see
00:09:30 --> 00:09:32 people at night if you're using a thermal
00:09:32 --> 00:09:33 imaging camera because they're warmer than
00:09:33 --> 00:09:35 the surrounding area, so they give off more
00:09:35 --> 00:09:38 infrared radiation. You can see that. But the
00:09:38 --> 00:09:41 reason we had to launch IRAs was that you
00:09:41 --> 00:09:43 can't do infrared astronomy from the ground
00:09:43 --> 00:09:45 except a couple of very specific wavelengths.
00:09:45 --> 00:09:47 And uh, the reason that you can't do infrared
00:09:47 --> 00:09:48 astronomy from the ground is that the
00:09:48 --> 00:09:51 atmosphere is fundamentally opaque at
00:09:51 --> 00:09:53 infrared wavelengths. And a big part of that
00:09:53 --> 00:09:56 is carbon dioxide. So if you've got a photon
00:09:56 --> 00:09:58 of infrared radiation, it coming into our
00:09:58 --> 00:10:00 atmosphere, we'll essentially see our
00:10:00 --> 00:10:02 atmosphere as utterly thick cloud. It will be
00:10:02 --> 00:10:04 absorbed and re emitted back out.
00:10:05 --> 00:10:08 Optical light, visible light makes it through
00:10:08 --> 00:10:09 the atmosphere intact. And that's why if I
00:10:09 --> 00:10:11 look out of the window at the minute, we've
00:10:11 --> 00:10:13 got a lovely sunny day and I can see what I'm
00:10:13 --> 00:10:15 doing. And, um, that solar radiation comes in
00:10:15 --> 00:10:17 and it warms the Earth up. And what does the
00:10:17 --> 00:10:19 Earth do? It radiates that energy back
00:10:19 --> 00:10:22 outward at infrared wavelengths. But because
00:10:22 --> 00:10:23 the atmosphere is opaque at infrared
00:10:23 --> 00:10:25 wavelengths, that energy gets absorbed and re
00:10:25 --> 00:10:28 emitted. And it'll be re emitted randomly in
00:10:28 --> 00:10:30 any given direction. So the odds are it'll
00:10:30 --> 00:10:32 come back down. So in other words, that
00:10:32 --> 00:10:34 radiation gets trapped. And that's how the
00:10:34 --> 00:10:36 doona works. That's how the carbon dioxide's
00:10:36 --> 00:10:39 working. Now the carbon dioxide
00:10:39 --> 00:10:41 we've got in our atmosphere is really
00:10:41 --> 00:10:44 effective as a greenhouse gas. It's actually
00:10:44 --> 00:10:46 mostly saturated. So adding
00:10:47 --> 00:10:49 some carbon dioxide from no carbon dioxide
00:10:49 --> 00:10:51 would have a much bigger effect than adding
00:10:51 --> 00:10:53 carbon dioxide to the atmosphere. Now, when
00:10:53 --> 00:10:55 we've got a fair bit of it in there already,
00:10:55 --> 00:10:57 but it's not totally saturated. So what that
00:10:57 --> 00:11:00 means is as we add more carbon dioxide, it
00:11:00 --> 00:11:02 can still have a bigger effect. And, um,
00:11:02 --> 00:11:04 that's why as we put more carbon dioxide into
00:11:04 --> 00:11:06 the atmosphere, the Earth gets warmer because
00:11:06 --> 00:11:08 the Dooner gets more effective.
00:11:09 --> 00:11:10 There are other gases that are effective
00:11:10 --> 00:11:12 greenhouse gases as well. Methane is a really
00:11:12 --> 00:11:14 good example. Methane is actually much more
00:11:14 --> 00:11:16 effective than carbon dioxide. But the
00:11:16 --> 00:11:18 difference is methane's fairly short lived in
00:11:18 --> 00:11:21 the atmosphere. Methane molecules on average
00:11:21 --> 00:11:22 will be removed from the atmosphere within
00:11:22 --> 00:11:25 400 years by interacting with oxygen.
00:11:25 --> 00:11:28 Carbon dioxide is only removed by life
00:11:28 --> 00:11:31 or by weathering. You know, if you get lots
00:11:31 --> 00:11:33 of rain on the continents, that breaks up the
00:11:33 --> 00:11:36 rocks, the rocks crumble down. Chemistry
00:11:36 --> 00:11:38 happens. Carbon dioxide can be pulled out
00:11:38 --> 00:11:40 into the rocks and locked up in the surface.
00:11:41 --> 00:11:42 They're the mechanisms that get rid of carbon
00:11:42 --> 00:11:45 dioxide and they're slower. So that's part of
00:11:45 --> 00:11:46 why carbon dioxide is a problem, because when
00:11:46 --> 00:11:48 we put it in the atmosphere, it's going to
00:11:48 --> 00:11:51 hang around for a good long time. But that
00:11:51 --> 00:11:52 hopefully kind of answers that question, that
00:11:52 --> 00:11:55 I am respectful of the fact that it's hard
00:11:55 --> 00:11:58 for people to comprehend how we
00:11:58 --> 00:12:00 can change the world's environment. Because
00:12:00 --> 00:12:01 you think of yourself and your friends and
00:12:01 --> 00:12:04 you think the Earth's so big and we're so
00:12:04 --> 00:12:05 small, how can we have that much of an
00:12:05 --> 00:12:08 effect? And it's hard to come to terms with
00:12:08 --> 00:12:09 just how many people there are and just how
00:12:09 --> 00:12:11 much stuff we're doing and pumping stuff into
00:12:11 --> 00:12:14 the atmosphere. Yeah, it's a bit
00:12:14 --> 00:12:17 misleading to say, you know, if you change to
00:12:17 --> 00:12:19 an EV rather than a petrol car, you'll save
00:12:19 --> 00:12:21 the world, but it'll contribute a little drop
00:12:21 --> 00:12:24 in the ocean towards lessening climate
00:12:24 --> 00:12:26 change potentially in the long term. And, um,
00:12:27 --> 00:12:29 that's kind of what people are looking at.
00:12:29 --> 00:12:31 But fundamentally, this is what's happening.
00:12:31 --> 00:12:33 It's very, very well established. Nothing
00:12:33 --> 00:12:36 astronomically can even come close to
00:12:36 --> 00:12:38 explaining what we're seeing. So when you
00:12:38 --> 00:12:40 rule out all the other options, the only
00:12:40 --> 00:12:41 thing that's left is human influence. And
00:12:41 --> 00:12:44 that's kind of sad, but shows what an
00:12:44 --> 00:12:46 effective species we are at changing our
00:12:46 --> 00:12:47 environment, you know?
00:12:47 --> 00:12:49 Andrew Dunkley: Well, hopefully we can be just as effective
00:12:49 --> 00:12:52 in finding a solution, but I think, uh,
00:12:52 --> 00:12:54 to do that, everybody has to be on the same
00:12:54 --> 00:12:56 page, and that's just not the case at the
00:12:56 --> 00:12:56 moment.
00:12:56 --> 00:12:57 Jonti Horner: I'm an optimist. I mean, there's.
00:12:59 --> 00:13:00 There's real challenges here. I remember
00:13:00 --> 00:13:03 there was an incredible article by a guy
00:13:03 --> 00:13:05 called Jeff Masters who used to run the
00:13:05 --> 00:13:07 Weather Underground site, used to write blogs
00:13:07 --> 00:13:10 there. Uh, yeah. Um, and he wrote about. I
00:13:10 --> 00:13:11 think it was book review, actually. But he
00:13:11 --> 00:13:13 wrote about something called Manufactured
00:13:13 --> 00:13:16 Doubt, which is a whole industry that has
00:13:16 --> 00:13:19 sprung up to sow confusion
00:13:19 --> 00:13:21 over something that should be settled science
00:13:21 --> 00:13:24 in order to allow business to operate without
00:13:24 --> 00:13:26 being restricted effectively. And, um, it
00:13:26 --> 00:13:29 first came about with smoking. So cigarette
00:13:29 --> 00:13:31 smoking. Tobacco smoking was known to be very
00:13:31 --> 00:13:34 harmful to people going back 100 years from
00:13:34 --> 00:13:36 now. But even when I was growing up in the
00:13:36 --> 00:13:38 1980s, he still had smoking in public places.
00:13:38 --> 00:13:40 You still had it everywhere. You still have
00:13:40 --> 00:13:42 adverts on TV and tobacco sponsorship.
00:13:43 --> 00:13:45 Because there'd been this very cleverly
00:13:45 --> 00:13:48 managed marketing strategy of casting doubt
00:13:48 --> 00:13:49 on the science and casting doubt on the
00:13:49 --> 00:13:51 scientists involved, effectively slandering
00:13:51 --> 00:13:53 them. And you have things like, you know, top
00:13:53 --> 00:13:55 sportsmen in the world, footballers and
00:13:55 --> 00:13:57 cricketers and things like this being
00:13:57 --> 00:13:59 sponsored by tobacco companies and smoking
00:13:59 --> 00:14:01 cigarettes and interviews and giving this
00:14:01 --> 00:14:03 impression. Can't be harmful, can it? I mean,
00:14:03 --> 00:14:05 look, here's one of the fittest athletes in
00:14:05 --> 00:14:06 the world and they smoke and that makes them
00:14:06 --> 00:14:08 a great athlete. You shouldn't see children.
00:14:09 --> 00:14:11 And what was interesting in this article from
00:14:11 --> 00:14:14 Jeff Masters, who's a very powerful advocate
00:14:14 --> 00:14:16 for knowledge, uh, about climate change, was
00:14:16 --> 00:14:18 that, uh, there is a lot of evidence that the
00:14:18 --> 00:14:20 companies that used to do that for tobacco
00:14:21 --> 00:14:24 through the 1980s were brought on board by
00:14:24 --> 00:14:27 the big oil companies to do the same kind of
00:14:27 --> 00:14:29 strategy. And it's been incredibly effective.
00:14:30 --> 00:14:33 And I think it's led to this wider thing of
00:14:34 --> 00:14:36 diminishing trust in science and greater
00:14:36 --> 00:14:38 doubt in it, which has led to the challenges
00:14:38 --> 00:14:40 we face now with things like vaccines, with,
00:14:40 --> 00:14:43 you know, flat earthing to some degree, with
00:14:43 --> 00:14:46 places where people are skeptical and
00:14:46 --> 00:14:48 don't trust scientists and don't trust
00:14:48 --> 00:14:49 science, even though science is so
00:14:49 --> 00:14:51 fundamental and foundational for our day to
00:14:51 --> 00:14:54 day lives. And it's really sad. But the flip
00:14:54 --> 00:14:56 side is we got cigarettes banned,
00:14:56 --> 00:14:59 people's health has improved. We, you know,
00:14:59 --> 00:15:01 no longer do you go to a pub and the walls
00:15:01 --> 00:15:03 are grimy and the windows are dark because of
00:15:03 --> 00:15:04 all the cigarette smoke. No longer do you get
00:15:04 --> 00:15:07 on a train and have to cough your way to your
00:15:07 --> 00:15:09 destination. Things have changed and I think
00:15:09 --> 00:15:11 we're starting to see the same change with
00:15:11 --> 00:15:13 climate change and, um, with the actions that
00:15:13 --> 00:15:15 we can take. And it's not happening out of
00:15:15 --> 00:15:16 the goodness of people's hearts. It's
00:15:16 --> 00:15:18 happening because commercially it's now
00:15:18 --> 00:15:21 becoming viable to make the changes. Yes,
00:15:21 --> 00:15:23 electric vehicles are a really good example.
00:15:24 --> 00:15:26 Back in the early 1900s you had electric
00:15:26 --> 00:15:28 vehicles, we had electric milk floats in the
00:15:28 --> 00:15:29 uk, but they were an oddity and there were
00:15:29 --> 00:15:32 specific use. But it's finally got to the
00:15:32 --> 00:15:33 point where those kind of vehicles can be
00:15:33 --> 00:15:36 competitive with combustion engine vehicles,
00:15:37 --> 00:15:38 can even possibly work out cheaper and more
00:15:38 --> 00:15:40 efficient and suddenly there's an incentive
00:15:40 --> 00:15:42 for people to get them, not because they're
00:15:42 --> 00:15:43 doing good for the planet, but because it's a
00:15:43 --> 00:15:45 better option for them. And that's the kind
00:15:45 --> 00:15:47 of change that hopefully is going to improve
00:15:47 --> 00:15:47 things.
00:15:47 --> 00:15:50 Andrew Dunkley: Yes, yes, I hope you're right. I
00:15:50 --> 00:15:53 suppose the other difficulty that comes into
00:15:53 --> 00:15:56 play with trying to change the minds of
00:15:56 --> 00:15:59 people and get the right thinking happening
00:15:59 --> 00:16:02 is social media, because there's so much
00:16:02 --> 00:16:04 scandal going through social media and as
00:16:04 --> 00:16:07 I mentioned, in the last program, um,
00:16:08 --> 00:16:11 we now have artificial intelligence, so
00:16:11 --> 00:16:13 you don't even know what you're looking at is
00:16:13 --> 00:16:14 real anymore.
00:16:14 --> 00:16:14 Speaker C: It's.
00:16:15 --> 00:16:18 Jonti Horner: Yeah, it's all saying that. And
00:16:18 --> 00:16:20 I know it from a Terry Pratchett. But like
00:16:20 --> 00:16:21 many things, Terry Pratchett, he was probably
00:16:22 --> 00:16:24 referencing people before. But this whole
00:16:24 --> 00:16:26 idea that a lie can run around the world
00:16:26 --> 00:16:28 before the truth can get its boots on, it's
00:16:28 --> 00:16:30 very easy to tell a convenient lie. And
00:16:30 --> 00:16:33 people are naturally biased as
00:16:33 --> 00:16:35 humans, with all the different cognitive
00:16:35 --> 00:16:37 biases we've got, there's a confirmation bias
00:16:37 --> 00:16:39 that you remember the things that fit in well
00:16:39 --> 00:16:41 with your lived experience and not the things
00:16:41 --> 00:16:43 that disagree with it. And, um, my lived
00:16:43 --> 00:16:45 experience is that I don't change the world
00:16:45 --> 00:16:47 when I go around. I'm not fundamentally
00:16:47 --> 00:16:48 altering the world around me, which I live
00:16:48 --> 00:16:50 in. So it's very easy when somebody says,
00:16:50 --> 00:16:53 we're not changing the world. Climate change
00:16:53 --> 00:16:55 can't be real, because how could you change
00:16:55 --> 00:16:57 the world for people to really empathize with
00:16:57 --> 00:16:59 that and fit in with it in just the same way
00:16:59 --> 00:17:02 that people who are getting vaccinated,
00:17:02 --> 00:17:04 they'll remember that their anti ulcer had a
00:17:04 --> 00:17:06 bad reaction to the vaccine, but they don't
00:17:06 --> 00:17:09 remember that many people who have had the
00:17:09 --> 00:17:11 vaccine and not had a reaction, but didn't
00:17:11 --> 00:17:12 die from the thing they were vaccinated
00:17:12 --> 00:17:15 against because they were vaccinated. So you
00:17:15 --> 00:17:17 get that confirmation bias that feels like it
00:17:17 --> 00:17:19 supports the idea that vaccines are bad
00:17:20 --> 00:17:22 when in fact they're not. And fundamentally,
00:17:22 --> 00:17:24 this is why as scientists, we use statistics
00:17:24 --> 00:17:26 for all these things. Lies down, blind
00:17:26 --> 00:17:29 statistics. We use statistics to try and
00:17:29 --> 00:17:31 avoid falling into the trap of our own biases
00:17:32 --> 00:17:33 because we think we've seen a pattern, but
00:17:33 --> 00:17:35 statistics will give us a hint as to whether
00:17:35 --> 00:17:36 it's really there or not.
00:17:37 --> 00:17:40 Andrew Dunkley: Yeah. Gosh, we could talk forever on this.
00:17:41 --> 00:17:43 It's like opening that can of worms and just
00:17:43 --> 00:17:45 letting it spill out and everybody has a go.
00:17:45 --> 00:17:47 Uh, thank you, Peter. We're going to sort of
00:17:47 --> 00:17:50 continue on to this type of, um, angle, uh,
00:17:50 --> 00:17:52 with a, uh, question from Paul.
00:17:53 --> 00:17:55 Speaker C: G', day, Space nuts. Paul Feen from Sunny
00:17:55 --> 00:17:58 Bridges, Vegas here. Quick question. If
00:17:58 --> 00:18:01 our Earth were to suddenly or not suddenly
00:18:01 --> 00:18:04 become a snowball, as
00:18:04 --> 00:18:06 might have happened if our, uh, scientific
00:18:06 --> 00:18:09 theories are correct, you know, back in our
00:18:09 --> 00:18:11 deep, distant past, what effect
00:18:11 --> 00:18:14 would that have on oxygen levels in our
00:18:14 --> 00:18:17 atmosphere? Would they
00:18:17 --> 00:18:19 stay the same? Uh, would they drop? Because
00:18:19 --> 00:18:22 plants don't grow really well down in
00:18:22 --> 00:18:24 Antarctica. I'd be curious to
00:18:24 --> 00:18:27 know your thoughts on this. Also
00:18:27 --> 00:18:29 what kind of events would actually trigger
00:18:29 --> 00:18:32 that in the first place? Anyway, keep doing a
00:18:32 --> 00:18:34 great job. Whoever happens to be at helm of
00:18:34 --> 00:18:37 the good ship Space Huts, uh, big shout out
00:18:37 --> 00:18:40 to Heidi Campo. Wow, what a great job
00:18:40 --> 00:18:43 he did. Thank you. And Jonti, wherever you
00:18:43 --> 00:18:45 are, uh, would love to hear from you again if
00:18:45 --> 00:18:48 Fred goes off gallivanting over to, I don't
00:18:48 --> 00:18:51 know, Norway or somewhere like that to see
00:18:51 --> 00:18:53 the northern lights. Cheers.
00:18:54 --> 00:18:56 Andrew Dunkley: Thank you, Paul. Well, guess what, that's
00:18:56 --> 00:18:59 exactly what's happened. And uh, Jonti
00:18:59 --> 00:19:01 is with us because of Fred's gallivanting.
00:19:02 --> 00:19:05 So, um, yes, you get to answer Paul's
00:19:05 --> 00:19:07 question about snowball Earth. Uh, the effect
00:19:07 --> 00:19:10 on O2 levels and what sort of, uh, events
00:19:10 --> 00:19:11 would trigger it.
00:19:11 --> 00:19:13 Jonti Horner: That's great. And there's a lot to this and
00:19:13 --> 00:19:14 it's good to hear from a local. So, yeah,
00:19:14 --> 00:19:16 thank you. And hi from.
00:19:16 --> 00:19:17 Andrew Dunkley: You're just up the road.
00:19:17 --> 00:19:19 Jonti Horner: I'm just up the road. Only a couple of
00:19:19 --> 00:19:21 hundred Ks inland. So, yeah, good hear from a
00:19:21 --> 00:19:24 local. This is. This sent me down some
00:19:24 --> 00:19:25 rabbit holes actually. I was digging into
00:19:25 --> 00:19:27 this and it's fascinating. So I've never
00:19:27 --> 00:19:30 actually had that thought of how snowball
00:19:30 --> 00:19:32 Earth episodes could link to oxygen before.
00:19:32 --> 00:19:34 And it's a really, really, really good
00:19:34 --> 00:19:36 question. So almost answer these kind of
00:19:36 --> 00:19:38 things in a bit of reverse order.
00:19:39 --> 00:19:41 The idea is, for those who aren't familiar
00:19:41 --> 00:19:43 with it, that at a couple of occasions in the
00:19:43 --> 00:19:44 past, one a bit more than 2 billion years
00:19:44 --> 00:19:47 ago, 1, 600, 500 million years ago,
00:19:48 --> 00:19:50 the Earth's climate went across a tipping
00:19:50 --> 00:19:53 point and like the ice age began, but the
00:19:53 --> 00:19:55 glaciers just kept advancing and you ended up
00:19:55 --> 00:19:58 with pretty much the entire planet clad in
00:19:58 --> 00:20:01 ice. And conditions at the equator at
00:20:01 --> 00:20:03 that point could even have been colder than
00:20:03 --> 00:20:05 we see in Antarctica right now. So really
00:20:05 --> 00:20:08 kind of dramatic conditions. And that lasted
00:20:08 --> 00:20:10 for a few million, even tens of millions of
00:20:10 --> 00:20:13 years before that condition got broken.
00:20:14 --> 00:20:16 And it makes perfect sense now. The climate
00:20:16 --> 00:20:18 of the, uh, Earth is relatively stable at the
00:20:18 --> 00:20:20 minute. We've just talked about our impact on
00:20:20 --> 00:20:23 it. But, um, on geological timescales, our
00:20:23 --> 00:20:26 climate tends to sit around a fairly stable
00:20:26 --> 00:20:29 point. But what the snowball Earth idea
00:20:29 --> 00:20:32 is reminding us of is that you have a
00:20:32 --> 00:20:34 few possible stable scenarios for the Earth's
00:20:34 --> 00:20:37 climate, of which we are one, we're one,
00:20:37 --> 00:20:39 which is essentially the warm version. But
00:20:39 --> 00:20:41 equally, if you turn the Earth into a
00:20:41 --> 00:20:44 snowball, it will remain a snowball for a
00:20:44 --> 00:20:46 very long time. And uh, the reason for that
00:20:46 --> 00:20:47 is that, uh, if you make the Earth a
00:20:47 --> 00:20:49 snowball, it becomes incredibly More
00:20:49 --> 00:20:52 reflective. And so therefore it absorbs
00:20:52 --> 00:20:54 less energy and so it stays cold. You get
00:20:54 --> 00:20:56 this kind of feedback that keeps the Earth
00:20:56 --> 00:20:59 cold. And the idea is when you flip from one
00:20:59 --> 00:21:01 state to another, you can be locked in that
00:21:01 --> 00:21:02 new state for a very long time until
00:21:02 --> 00:21:05 something changes. Now what could cause
00:21:05 --> 00:21:08 that? One thing that could cause that is
00:21:09 --> 00:21:11 life on our planet. Removing carbon dioxide
00:21:11 --> 00:21:13 from the atmosphere and weathering on the
00:21:13 --> 00:21:15 continents. Removing carbon dioxide from the
00:21:15 --> 00:21:18 atmosphere at, ah, a rate that cools a planet
00:21:18 --> 00:21:20 quicker than the sun getting brighter, warms
00:21:20 --> 00:21:22 a planet. So the sun, when the Earth was very
00:21:22 --> 00:21:25 young, was probably about 30% dimmer. And the
00:21:25 --> 00:21:28 sun is thought to brighten by about 6 or
00:21:28 --> 00:21:31 7% every billion years. So it's 30%
00:21:31 --> 00:21:32 brighter now than it was when the Earth
00:21:32 --> 00:21:35 formed. So the question is, if the sun was so
00:21:35 --> 00:21:36 dim when the Earth was young, how were we
00:21:36 --> 00:21:38 warm enough to have liquid water? And the
00:21:38 --> 00:21:41 answer is, at that point we had a hugely rich
00:21:41 --> 00:21:43 atmosphere of greenhouse gases, things like
00:21:43 --> 00:21:46 carbon dioxide and methane and no oxygen. And
00:21:46 --> 00:21:48 so the atmosphere was very, very rich in
00:21:48 --> 00:21:50 things that would create a really thick doona
00:21:51 --> 00:21:53 and we were very, very pleasantly warm.
00:21:54 --> 00:21:56 Over time, the sun has got brighter, but
00:21:56 --> 00:21:58 life and weathering have removed the
00:21:58 --> 00:22:01 greenhouse gases from the atmosphere and
00:22:01 --> 00:22:03 averaged over the entire age of the Earth,
00:22:03 --> 00:22:05 those two things have roughly balanced out.
00:22:06 --> 00:22:08 And so we still have a temperate climate. Now
00:22:08 --> 00:22:09 if we had the atmosphere the Earth had when
00:22:09 --> 00:22:12 it was young, the Earth would be like Venus
00:22:12 --> 00:22:13 now. The oceans would have boiled and we
00:22:13 --> 00:22:15 wouldn't be having this conversation. Yeah,
00:22:16 --> 00:22:18 but the climate has kind of fortunately
00:22:18 --> 00:22:21 stayed for most of its time in the kind
00:22:21 --> 00:22:24 of warm, stable version. But there have
00:22:24 --> 00:22:26 been these two big occasions that have had
00:22:26 --> 00:22:29 the snowball Earth scenario. Now
00:22:29 --> 00:22:31 there's some debate over, uh, exactly what
00:22:31 --> 00:22:32 triggered that. And it's likely there were a
00:22:32 --> 00:22:35 few things. There was life and increased
00:22:35 --> 00:22:37 weathering, pulling carbon dioxide out of the
00:22:37 --> 00:22:38 atmosphere. So you weaken the greenhouse
00:22:38 --> 00:22:41 effect and cool the planet down. That is
00:22:41 --> 00:22:44 most likely. You also have a scenario,
00:22:44 --> 00:22:46 incidentally, where if you make the Earth
00:22:46 --> 00:22:49 more reflective around the equator, you lower
00:22:49 --> 00:22:51 the amount of heat that's absorbed by the
00:22:51 --> 00:22:52 Earth, increase the amount reflected and you
00:22:52 --> 00:22:54 cool the Earth as well. So what are the
00:22:54 --> 00:22:56 scenarios that's proposed to explain how we
00:22:56 --> 00:22:59 got into the snowball Earth periods? At first
00:22:59 --> 00:23:01 was that you got a period where you got one
00:23:01 --> 00:23:03 of these supercontinents where all the
00:23:03 --> 00:23:04 continental material on the Earth kind of
00:23:04 --> 00:23:07 smushed together, like we had with Pangea,
00:23:07 --> 00:23:09 like was proposed with Pangaea. Previous
00:23:09 --> 00:23:11 episode of that. We have most of the Earth's
00:23:11 --> 00:23:14 continents around the Earth's, uh, equator,
00:23:15 --> 00:23:17 continental material, rock and, um,
00:23:17 --> 00:23:19 vegetation and everything else is more
00:23:19 --> 00:23:21 reflective than water. And in fact, most of
00:23:21 --> 00:23:24 the energy coming into the Earth these, ah,
00:23:24 --> 00:23:26 days is absorbed by the water. The water is
00:23:26 --> 00:23:27 the main thing that locks in the heat and
00:23:27 --> 00:23:30 keeps us warm. And that, of course, is why
00:23:30 --> 00:23:32 Brisbane gets so warm and humid in the
00:23:32 --> 00:23:34 summers. It's why Western Europe is so
00:23:34 --> 00:23:36 pleasant in the winters compared to the
00:23:36 --> 00:23:39 middle of Canada. The water carries a lot of
00:23:39 --> 00:23:41 heat, holds onto it for a long, long time. So
00:23:41 --> 00:23:43 you have this speculative scenario where
00:23:44 --> 00:23:46 all the continents end up smushed up and near
00:23:46 --> 00:23:48 the Earth's equator. So the Earth's albedo
00:23:48 --> 00:23:50 gets more reflective, a higher
00:23:50 --> 00:23:53 albedo, so the Earth would naturally cool
00:23:53 --> 00:23:54 because it's absorbing less heat and
00:23:54 --> 00:23:57 reflecting more. Added to which, if you put
00:23:57 --> 00:23:58 the continents nearer the equator, you're in
00:23:58 --> 00:24:00 a location which gets much higher rainfall
00:24:00 --> 00:24:03 and much higher weather levels because the
00:24:03 --> 00:24:05 water at that latitude is hotter, so
00:24:05 --> 00:24:06 evaporates more. The atmosphere can hold more
00:24:06 --> 00:24:09 water, so you get more weathering, which
00:24:09 --> 00:24:11 drives more chemistry, which also acts to
00:24:11 --> 00:24:12 pull more carbon dioxide out of the
00:24:12 --> 00:24:14 atmosphere. And, um, that exacerbates this
00:24:14 --> 00:24:17 and we, you know, removes the greenhouse
00:24:17 --> 00:24:19 effect as well. So you've got more energy
00:24:19 --> 00:24:21 being reflected and less absorbed. So the
00:24:21 --> 00:24:23 Earth cools more carbon dioxide pulled out of
00:24:23 --> 00:24:25 the atmosphere, so the greenhouse effect
00:24:25 --> 00:24:28 weakens, so the Earth cools. That then
00:24:28 --> 00:24:30 causes the Earth to start entering ice ages
00:24:30 --> 00:24:32 where the water near the poles freezes and
00:24:32 --> 00:24:35 the ice expands towards the equator. That
00:24:35 --> 00:24:37 ice is more reflective than the water that it
00:24:37 --> 00:24:40 sits on is. So less energy is absorbed and
00:24:40 --> 00:24:42 more is reflected. And so the Earth cools.
00:24:42 --> 00:24:44 And so you get this feedback effect where the
00:24:44 --> 00:24:46 ice gradually reaches down towards the
00:24:46 --> 00:24:48 equator. And once you're in that scenario,
00:24:48 --> 00:24:50 you're in a position where even if you put
00:24:50 --> 00:24:52 all the carbon dioxide back in the
00:24:52 --> 00:24:54 atmosphere, the Earth is so reflective that
00:24:54 --> 00:24:57 it will stay cold. You're locked into this
00:24:57 --> 00:25:00 other stable state. However, longer
00:25:00 --> 00:25:02 term, what happens is that, uh, you've got
00:25:02 --> 00:25:04 the ice sheet now sat over all of the rocks.
00:25:04 --> 00:25:06 So you prevent the weathering that was
00:25:06 --> 00:25:08 removing carbon dioxide from the atmosphere.
00:25:08 --> 00:25:11 You turn that off, you've still got things
00:25:11 --> 00:25:12 putting carbon dioxide back in the
00:25:12 --> 00:25:12 atmosphere.
00:25:12 --> 00:25:14 You've still got volcanoes erupting and all
00:25:14 --> 00:25:17 the sources of gases that were putting it
00:25:17 --> 00:25:18 back into the atmosphere and eventually
00:25:18 --> 00:25:20 return the weather, material, weather gases
00:25:20 --> 00:25:22 into the atmosphere. So you're in the
00:25:22 --> 00:25:24 snowball, uh, Earth setup. But gradually over
00:25:24 --> 00:25:26 time, then your greenhouse gas levels rise
00:25:26 --> 00:25:29 and rise and rise until eventually you start
00:25:29 --> 00:25:31 to melt the ice and you get this other
00:25:31 --> 00:25:34 tipping point where suddenly you're warm
00:25:34 --> 00:25:37 enough for the ice to melt and retreat, which
00:25:37 --> 00:25:39 means you expose more water, more water is
00:25:39 --> 00:25:42 exposed, which means more area to absorb the
00:25:42 --> 00:25:43 heat, which means the Earth will warm up
00:25:43 --> 00:25:45 more, which means more ice melts, and you go
00:25:45 --> 00:25:48 back to being this kind of warmer, uh, Earth.
00:25:49 --> 00:25:51 That brings with it, though, a time when
00:25:51 --> 00:25:53 you've had the continents crunched up under
00:25:53 --> 00:25:56 ice sheets, broken up into kind of gravelly
00:25:56 --> 00:25:58 small bits of debris. And then when you start
00:25:58 --> 00:26:00 raining on that again, you get a huge amount
00:26:00 --> 00:26:02 of weathering water washing out
00:26:03 --> 00:26:04 minerals and putting it into the ocean.
00:26:06 --> 00:26:07 And that means that suddenly all that life
00:26:07 --> 00:26:09 that has been starved through the snowball
00:26:09 --> 00:26:12 Earth epoch is suddenly going, hey, look, the
00:26:12 --> 00:26:13 Earth's nice and warm. It's a nice place to
00:26:13 --> 00:26:16 live again. Brilliant. And, oh, look, there's
00:26:16 --> 00:26:18 suddenly all this food in the oceans. And so
00:26:18 --> 00:26:20 the papers that I came across when I was
00:26:20 --> 00:26:22 looking into this as a result of Paul's
00:26:22 --> 00:26:25 question, it seems that after both of the big
00:26:25 --> 00:26:27 snowball Earth eras, there was a massive
00:26:27 --> 00:26:30 oxygenation event on Earth. So after the
00:26:30 --> 00:26:32 first one, you went from effectively no
00:26:32 --> 00:26:34 oxygen in Earth's atmosphere to Earth's
00:26:34 --> 00:26:35 atmosphere being about 2%
00:26:36 --> 00:26:38 oxygen, which is a big jump from nothing to
00:26:38 --> 00:26:40 2%. And, um, then
00:26:41 --> 00:26:43 6 million years ago,
00:26:44 --> 00:26:46 you had the end of the most recent snowball
00:26:46 --> 00:26:47 Earth thing, and you got another mass
00:26:47 --> 00:26:50 oxygenation event. Why suddenly you've
00:26:50 --> 00:26:52 got all this nutrient and all this stuff
00:26:52 --> 00:26:55 washing off into the oceans, prime conditions
00:26:55 --> 00:26:57 for things to grow and a huge amount of
00:26:57 --> 00:27:00 oxygen released. And, um, that is thought to
00:27:00 --> 00:27:01 have been what drove oxygen up to something
00:27:01 --> 00:27:04 comparable to its current levels relatively
00:27:04 --> 00:27:07 quickly. And that then led to there
00:27:07 --> 00:27:09 being sufficient free evidence for what's
00:27:09 --> 00:27:10 called, I think, the Cambrian explosion,
00:27:10 --> 00:27:13 where suddenly you've got an Earth that has
00:27:13 --> 00:27:16 all these different niches suddenly freed up
00:27:16 --> 00:27:18 and the source of ready oxygen, and
00:27:18 --> 00:27:20 everything goes crazy evolving to fill the
00:27:20 --> 00:27:23 available opportunities. And
00:27:23 --> 00:27:26 so all of that kind of gives you an idea how
00:27:26 --> 00:27:27 we think snowball Earth episodes could
00:27:27 --> 00:27:30 happen. And, um, what would happen to oxygen
00:27:30 --> 00:27:32 afterwards? Which seems to be the accepted
00:27:32 --> 00:27:34 scientific wisdom, that after a snowball
00:27:34 --> 00:27:36 Earth episode, when it ends, you can get the
00:27:36 --> 00:27:38 oxygen suddenly getting significantly more
00:27:38 --> 00:27:41 oxygen rich as life takes advantage of the
00:27:41 --> 00:27:43 new conditions. What would happen to
00:27:43 --> 00:27:45 oxygen now that there's a lot of it in the
00:27:45 --> 00:27:47 atmosphere during the snowball Earth period,
00:27:47 --> 00:27:50 I couldn't find any speculation on. So
00:27:50 --> 00:27:52 it's a really interesting question. Now, it
00:27:52 --> 00:27:54 doesn't mean there's no speculation out
00:27:54 --> 00:27:55 there. It just means that I couldn't find any
00:27:55 --> 00:27:58 of his. Big difference there. But
00:27:58 --> 00:28:00 there's a few things that are going on that I
00:28:00 --> 00:28:02 think could be interesting. Firstly, there's
00:28:02 --> 00:28:04 a huge amount of oxygen in the atmosphere. So
00:28:04 --> 00:28:07 even if you stop producing it and you manage
00:28:07 --> 00:28:09 to keep alive the things that use it, it will
00:28:09 --> 00:28:11 probably go down very slowly just because
00:28:11 --> 00:28:13 there's uh, so much of it. And if you were
00:28:13 --> 00:28:16 killing off a lot of life, then
00:28:16 --> 00:28:18 to be honest, there's not as much using it
00:28:18 --> 00:28:21 anyway. Volcanoes erupting, carbon
00:28:21 --> 00:28:23 dioxide and particularly methane that's been
00:28:23 --> 00:28:26 erupted and outgassed, um, particularly
00:28:26 --> 00:28:28 towards the end of the ice age kind of
00:28:28 --> 00:28:31 period, getting lots of methane released into
00:28:31 --> 00:28:33 the atmosphere would remove the oxygen as the
00:28:33 --> 00:28:34 methane and the oxygen interact with each
00:28:34 --> 00:28:37 other. And if that was happening quicker than
00:28:37 --> 00:28:38 life was putting new oxygen into the
00:28:38 --> 00:28:40 atmosphere, then you can imagine that leading
00:28:40 --> 00:28:42 to a bit of a dip in the amount of oxygen in
00:28:42 --> 00:28:45 the atmosphere at the time. But my
00:28:45 --> 00:28:47 guess would be that probably during the
00:28:47 --> 00:28:50 snowball Earth period, the oxygen levels
00:28:50 --> 00:28:52 wouldn't change all that much. You might be
00:28:52 --> 00:28:54 producing less oxygen, but you'd also be
00:28:54 --> 00:28:56 using less. So that will balance out. But
00:28:56 --> 00:28:59 what you would get over time is, particularly
00:28:59 --> 00:29:01 if you killed off a lot of life, you get this
00:29:01 --> 00:29:04 slow, steady increase in
00:29:04 --> 00:29:06 greenhouse gas levels because you're still
00:29:06 --> 00:29:07 pumping out the same amount in terms of
00:29:07 --> 00:29:10 volcanism, but you've removed the weathering
00:29:10 --> 00:29:12 that's taking it away again. And so that
00:29:12 --> 00:29:15 would lead to the greenhouse gas level rising
00:29:15 --> 00:29:17 slowly over time until it got to the point
00:29:17 --> 00:29:19 where it turned it back over the tipping
00:29:19 --> 00:29:21 point and allowed the Earth to warm up again.
00:29:21 --> 00:29:23 And that will probably then be a very bad
00:29:23 --> 00:29:25 thing because the sun is now much more
00:29:25 --> 00:29:26 luminous than it ever has been in the past.
00:29:27 --> 00:29:29 If you get a runaway greenhouse effect now,
00:29:30 --> 00:29:32 that's a lot more problematic than it was 500
00:29:32 --> 00:29:34 million years ago. And maybe that could lead
00:29:34 --> 00:29:37 to conditions where you don't hit our current
00:29:37 --> 00:29:39 stable level, but you go past that and you
00:29:39 --> 00:29:42 end up hurrying the end of the Earth, uh, as
00:29:42 --> 00:29:43 a habitable world, effectively.
00:29:44 --> 00:29:45 Andrew Dunkley: Oh, fun. Yeah.
00:29:45 --> 00:29:46 Jonti Horner: Careful path.
00:29:47 --> 00:29:48 Andrew Dunkley: I, uh, just did a.
00:29:50 --> 00:29:53 I'll get some negative press for this, but,
00:29:53 --> 00:29:55 uh, I just did a, um, put uh, a question into
00:29:55 --> 00:29:58 chat. GPT Would, uh, current
00:29:58 --> 00:30:00 oxygen levels on Earth reduce if Earth were
00:30:00 --> 00:30:02 to freeze over? And uh, it's come up with a
00:30:02 --> 00:30:05 few scenarios, but basically says most, he
00:30:05 --> 00:30:07 he. It says most oxygen on Earth comes from
00:30:07 --> 00:30:10 photosynthetic organisms, uh, mainly
00:30:10 --> 00:30:12 marine plankton and land plants. If Earth
00:30:12 --> 00:30:15 froze over ocean, uh, uh, surfaces would
00:30:15 --> 00:30:17 be sealed under thick ice, preventing
00:30:17 --> 00:30:19 sunlight from reaching most marine
00:30:19 --> 00:30:22 photosynthesizers. Land plants would die or
00:30:22 --> 00:30:24 go dormant due to cold or lack of liquid
00:30:24 --> 00:30:27 water. So oxygen production would drop
00:30:27 --> 00:30:27 dramatically.
00:30:28 --> 00:30:30 Jonti Horner: And that makes sense, but I'd argue that
00:30:30 --> 00:30:32 oxygen use will drop dramatically as well
00:30:32 --> 00:30:33 because you kill the things that are using
00:30:33 --> 00:30:36 the oxygen. Yes. The other thing that I've
00:30:36 --> 00:30:37 stumb across in my reading actually, and that
00:30:37 --> 00:30:40 just reminded me of was one of the things
00:30:40 --> 00:30:42 that tied into this idea of the snowball
00:30:42 --> 00:30:44 earth stuff was how on earth did life make it
00:30:44 --> 00:30:46 through. And um, one of the things that
00:30:46 --> 00:30:48 people's modeling found was that even though
00:30:48 --> 00:30:50 you'd get ice all the way down to the
00:30:50 --> 00:30:52 equator, the processes that happen
00:30:52 --> 00:30:54 at uh, the equator will probably prevent that
00:30:54 --> 00:30:56 ice being more than about 10 meters thick.
00:30:57 --> 00:30:58 And uh, studies have shown that enough light
00:30:58 --> 00:31:00 can make it through ice for photosynthesis to
00:31:00 --> 00:31:03 continue unless the ice is 20 meters thick
00:31:03 --> 00:31:06 or more. And so there'd likely be a band
00:31:06 --> 00:31:08 where you could continue photosynthesis under
00:31:08 --> 00:31:09 the ice because the ice is not thick enough
00:31:09 --> 00:31:12 to block all the sunlight. That seemed to be
00:31:12 --> 00:31:14 the argument. There was some discussions of
00:31:14 --> 00:31:16 where the pockets of life holding on through
00:31:16 --> 00:31:19 the hellish times would be and that was quite
00:31:19 --> 00:31:20 interesting. But like I said, I'm not a
00:31:20 --> 00:31:22 biologist, so uh, that is straining my
00:31:22 --> 00:31:24 expertise to look at exactly how life would
00:31:24 --> 00:31:25 adapt to those conditions.
00:31:26 --> 00:31:28 Andrew Dunkley: Indeed. All right, Paul, thanks for the
00:31:28 --> 00:31:30 question. Great one. And uh, there might be
00:31:30 --> 00:31:33 more to talk about that, uh, in regard to
00:31:33 --> 00:31:35 that down the track. This is Space Nuts with
00:31:35 --> 00:31:38 Andrew Dunkley and Jonti Horner.
00:31:41 --> 00:31:43 Speaker C: Three, two, one.
00:31:44 --> 00:31:45 Jonti Horner: Space Nuts.
00:31:45 --> 00:31:47 Andrew Dunkley: Now Jonti, uh, a couple of questions have
00:31:47 --> 00:31:50 come in about uh, objects or
00:31:50 --> 00:31:52 events that have happened in space.
00:31:53 --> 00:31:55 Uh, Casey has messaged, um,
00:31:56 --> 00:31:58 us. Hello again, this is Casey from Colorado.
00:31:58 --> 00:32:01 I recently read a little bit about the record
00:32:01 --> 00:32:03 breaking KM M32302
00:32:04 --> 00:32:06 213A. Please correct me
00:32:06 --> 00:32:09 if I'm wrong, but detecting a 220
00:32:10 --> 00:32:12 PETA electron volt neutrino
00:32:12 --> 00:32:15 is pretty crazy considering that
00:32:15 --> 00:32:18 that's like 30 times more energetic than the
00:32:18 --> 00:32:20 previous record holder. Uh, what could
00:32:20 --> 00:32:22 possibly be its source? Love the podcast and
00:32:22 --> 00:32:25 hope you're both well. Thanks from Casey in
00:32:25 --> 00:32:27 Colorado and she hopes you're well too,
00:32:27 --> 00:32:27 Jonti.
00:32:29 --> 00:32:29 Speaker C: Yes.
00:32:29 --> 00:32:31 Andrew Dunkley: Then again she might be talking about Fred
00:32:31 --> 00:32:32 and Heidi. I don't know.
00:32:36 --> 00:32:37 Jonti Horner: So this is a really interesting one. I must
00:32:37 --> 00:32:40 say that I hadn't seen this announcement and
00:32:40 --> 00:32:42 so this was a really interesting thing to
00:32:42 --> 00:32:44 read about. Um, this is a neutrino that
00:32:45 --> 00:32:47 according to the name was seen in 2023,
00:32:47 --> 00:32:50 on February 13th. And, um, it was
00:32:50 --> 00:32:53 detected by this huge array of
00:32:53 --> 00:32:55 detectors on the bottom of the Mediterranean
00:32:55 --> 00:32:58 Ocean, Mediterranean Sea, about 3 and a half
00:32:58 --> 00:33:00 kilometers below sea level, in the pitch
00:33:00 --> 00:33:02 black of the deep ocean, where they have all
00:33:02 --> 00:33:05 these detectors that have the job of
00:33:05 --> 00:33:07 detecting incredibly faint flashes of light
00:33:08 --> 00:33:10 that occur when cosmic rays or neutrinos
00:33:11 --> 00:33:14 collide with an atom in the ocean and cause
00:33:14 --> 00:33:16 a cascade of light as this whole collision
00:33:16 --> 00:33:19 chain of, uh, particles being formed and
00:33:19 --> 00:33:21 energy being released as the energy from
00:33:21 --> 00:33:24 those things is dumped into the ocean. And
00:33:24 --> 00:33:26 this occurred before they'd finished building
00:33:26 --> 00:33:28 and testing this array. So it was during the
00:33:28 --> 00:33:30 testing phase, and it is
00:33:30 --> 00:33:32 reliably says on all of these websites, by
00:33:32 --> 00:33:35 far the most energetic neutrino ever
00:33:35 --> 00:33:38 detected. And it is so energetic
00:33:38 --> 00:33:41 that there is no source within our galaxy
00:33:41 --> 00:33:44 that could generate a neutrino that energetic
00:33:44 --> 00:33:46 that we know of. And if it had been generated
00:33:46 --> 00:33:48 by something nearby, we'd have seen other
00:33:48 --> 00:33:50 things happening. You might have seen a very
00:33:50 --> 00:33:53 powerful gamma ray burst or something like
00:33:53 --> 00:33:56 that. And, uh, no counterpart was detected.
00:33:56 --> 00:33:58 There was nothing that happened at this time
00:33:59 --> 00:34:01 that synced up with when this happened. Now
00:34:01 --> 00:34:03 should be said that when I search for this,
00:34:03 --> 00:34:04 there's a nice little article describing it
00:34:04 --> 00:34:07 by the Astrobytes website, which is
00:34:07 --> 00:34:10 a website run by graduate students in
00:34:10 --> 00:34:13 astrophysics in the US that tries to be a
00:34:13 --> 00:34:16 literature review journal club for
00:34:16 --> 00:34:18 other graduate students and, um, to give
00:34:18 --> 00:34:20 students an opportunity to practice science
00:34:20 --> 00:34:22 writing about things out of their field. And
00:34:22 --> 00:34:23 there's a bit of a description of it. There's
00:34:24 --> 00:34:25 um, and that's a nice little website if
00:34:25 --> 00:34:27 you're interested in getting a little
00:34:27 --> 00:34:29 snapshot summary of research papers to try
00:34:29 --> 00:34:32 and do one a day. But I also stumbled
00:34:32 --> 00:34:34 across the official page for this event,
00:34:35 --> 00:34:37 which is published by the network
00:34:38 --> 00:34:40 that are running these detectors. And that's
00:34:40 --> 00:34:42 got a lovely little YouTube Music video right
00:34:42 --> 00:34:44 at the top that you can watch. It's about two
00:34:44 --> 00:34:46 and a half minutes long that describes this
00:34:46 --> 00:34:48 thing, how it's detected, and some of the
00:34:48 --> 00:34:50 possible suggestions for its formation. Now,
00:34:51 --> 00:34:54 going beyond that to what could have created
00:34:54 --> 00:34:57 it is really pushing beyond the bounds of my
00:34:57 --> 00:34:59 knowledge and expertise. So I'm afraid,
00:35:00 --> 00:35:01 Casey, you're going to have to accept a
00:35:01 --> 00:35:04 journeyman's explanation based on what I was
00:35:04 --> 00:35:07 able to read around about this, which digs
00:35:07 --> 00:35:08 into things that I honestly don't fully
00:35:08 --> 00:35:11 understand. But the argument is, because of
00:35:11 --> 00:35:13 the incredibly high energy of this thing, it
00:35:13 --> 00:35:15 couldn't have been generated locally. And
00:35:15 --> 00:35:18 that points to an origin in the very distant
00:35:18 --> 00:35:20 and therefore very early universe.
00:35:21 --> 00:35:24 Now, there's some theories that fall
00:35:24 --> 00:35:25 under the branch of what I think is called
00:35:25 --> 00:35:28 quantum field theory that talk
00:35:28 --> 00:35:31 about there being photon
00:35:31 --> 00:35:34 fields permeating space. And
00:35:34 --> 00:35:35 I don't fully understand what that is and
00:35:35 --> 00:35:38 what that means, in all honesty. But
00:35:38 --> 00:35:41 the idea seems to be here that you've got
00:35:41 --> 00:35:42 radiation from the cosmic microwave
00:35:42 --> 00:35:44 background, or from very early in the
00:35:44 --> 00:35:47 universe that includes incredibly high energy
00:35:47 --> 00:35:49 radiation at, uh, that time,
00:35:50 --> 00:35:52 because that's a heat from the big Bang. Now,
00:35:52 --> 00:35:54 nowadays we see that as a cosmic microwave
00:35:54 --> 00:35:56 background. It's very low energy levels
00:35:56 --> 00:35:59 because it's been redshifted. But at the
00:35:59 --> 00:36:01 time, the energy levels were incredibly,
00:36:01 --> 00:36:02 incredibly high. And that means that these
00:36:03 --> 00:36:05 photon fields, if you follow the, um,
00:36:05 --> 00:36:08 quantum field theory ideas, were incredibly
00:36:08 --> 00:36:11 intense. Now, one of the ways that you can
00:36:11 --> 00:36:13 produce neutrinos that is predicted by this
00:36:14 --> 00:36:16 predicts what are called cosmogenic
00:36:16 --> 00:36:19 neutrinos. Now, it should be said that
00:36:19 --> 00:36:21 none of these have ever been detected until
00:36:21 --> 00:36:23 potentially this one. But it's one of the
00:36:23 --> 00:36:26 predictions that quantum field theory makes
00:36:26 --> 00:36:28 is that you should see these cosmogenic
00:36:28 --> 00:36:31 neutrinos that are generated by
00:36:31 --> 00:36:33 cosmic radiation rather than a specific event
00:36:33 --> 00:36:35 like a gamma ray burst or a supernova or
00:36:35 --> 00:36:38 something like that. And the idea is that in
00:36:38 --> 00:36:39 the very early universe, you've got these
00:36:39 --> 00:36:42 incredibly high amounts of energy. And that
00:36:42 --> 00:36:45 means that these photon fields, I think
00:36:45 --> 00:36:47 they're called, can interact with
00:36:47 --> 00:36:50 particles of matter. And, um, when you get
00:36:50 --> 00:36:52 this interaction, that can lead to the
00:36:52 --> 00:36:54 production of an incredibly high energy
00:36:54 --> 00:36:57 neutrino. Now, the very high energy
00:36:57 --> 00:37:00 neutrino, as we know, neutrinos, are,
00:37:00 --> 00:37:03 uh, about the weakest interacting things we
00:37:03 --> 00:37:06 know of. So once you produce a very high
00:37:06 --> 00:37:08 energy neutrino that can pass across the
00:37:08 --> 00:37:10 entire universe without interacting with
00:37:10 --> 00:37:12 anything, we've got millions of these things
00:37:12 --> 00:37:14 passing through our bodies as we speak, and
00:37:14 --> 00:37:16 we just don't feel them. Which incidentally,
00:37:16 --> 00:37:17 is why to detect them, you want to be at the
00:37:17 --> 00:37:19 bottom of the ocean or in a huge volume of
00:37:19 --> 00:37:22 water so that you maximize the number of
00:37:22 --> 00:37:24 atoms available for one of these to by chance
00:37:24 --> 00:37:26 collide with and give you the light show.
00:37:26 --> 00:37:28 Because you need a huge volume of water to
00:37:28 --> 00:37:30 get even one neutrino to hit something and
00:37:30 --> 00:37:32 give you a show, because they're that weakly
00:37:32 --> 00:37:32 interacting.
00:37:32 --> 00:37:33 Andrew Dunkley: Yeah.
00:37:33 --> 00:37:35 Jonti Horner: Once you produce these cosmogenic neutrinos,
00:37:35 --> 00:37:37 they then carry on through the universe
00:37:37 --> 00:37:39 forevermore at ridiculously high energies.
00:37:40 --> 00:37:42 Now, the bit I quite honestly don't
00:37:42 --> 00:37:44 understand with this, and none of the things
00:37:44 --> 00:37:46 I've read have been able to explain to me is
00:37:46 --> 00:37:49 the fact that uh, if this thing was
00:37:49 --> 00:37:52 created with the cosmic microwave
00:37:52 --> 00:37:55 background, I would have thought it should be
00:37:55 --> 00:37:57 redshifted by the expansion of the universe
00:37:58 --> 00:38:00 in the same way that photons are uh,
00:38:00 --> 00:38:03 the light we see it. And doing a bit of
00:38:03 --> 00:38:05 reading around it does seem that neutrinos
00:38:05 --> 00:38:07 can be gravitationally redshifted. So if you
00:38:07 --> 00:38:09 get a neutrino produced at the surface of a
00:38:09 --> 00:38:12 neutron star, that is one energy, by the
00:38:12 --> 00:38:13 time it escapes from the neutron star's
00:38:13 --> 00:38:15 gravity, it's lost energy and it's
00:38:15 --> 00:38:18 effectively redshifted. What I haven't been
00:38:18 --> 00:38:19 able to find out though is whether the
00:38:19 --> 00:38:22 expansion of the universe would redshift
00:38:22 --> 00:38:25 neutrinos and therefore lower their energy.
00:38:26 --> 00:38:29 Now if the expansion of the
00:38:29 --> 00:38:31 universe doesn't lower the energies then this
00:38:31 --> 00:38:32 makes perfect sense. You know, you've got
00:38:32 --> 00:38:34 this incredibly high energy neutrino that's
00:38:34 --> 00:38:36 tied to how high the energies were when the
00:38:36 --> 00:38:39 universe was young and it's only just reached
00:38:39 --> 00:38:42 us now. If they are redshifted then
00:38:42 --> 00:38:44 that makes this even more head scratchingly
00:38:44 --> 00:38:46 awesome because if it has been
00:38:46 --> 00:38:48 redshifted and its energy dropped by an
00:38:48 --> 00:38:51 incredible amount and it's still 220peta
00:38:51 --> 00:38:54 electron volts, what was its energy when it
00:38:54 --> 00:38:56 was formed? And I just don't fully understand
00:38:56 --> 00:38:58 that. So my knowledge is limited of this.
00:38:59 --> 00:39:01 I've done my best to read around it and get
00:39:01 --> 00:39:02 an understanding of what they think is going
00:39:02 --> 00:39:05 on. But I guess what
00:39:05 --> 00:39:08 comes out of this for me a, it's just a very
00:39:08 --> 00:39:11 cool detection. But if you want to push
00:39:11 --> 00:39:12 the boundaries of what we know and build
00:39:12 --> 00:39:15 theories of how the universe works, our
00:39:15 --> 00:39:17 theories will eventually go
00:39:17 --> 00:39:20 beyond our level to observe the things that
00:39:20 --> 00:39:22 they predict. A good example of this I always
00:39:22 --> 00:39:24 go back to because it's my own wheelhouse, is
00:39:24 --> 00:39:27 Newton's theories of gravitation which he
00:39:27 --> 00:39:30 published in like in Principia Mathematica in
00:39:30 --> 00:39:33 1680, 1682. Around then, um, and that
00:39:33 --> 00:39:35 gave us mathematical tools that allowed us to
00:39:35 --> 00:39:37 work how things moved in gravitational
00:39:37 --> 00:39:39 fields, allowed us to work out orbits and
00:39:39 --> 00:39:40 predict things in the future. And that's been
00:39:40 --> 00:39:43 incredibly powerful. By the
00:39:43 --> 00:39:46 1800s observations were
00:39:46 --> 00:39:48 starting to show that the orbit of Mercury
00:39:48 --> 00:39:51 was behaving slightly different to how
00:39:51 --> 00:39:53 Newton's gravitation will predict it would
00:39:53 --> 00:39:56 work. That effectively led to the precession
00:39:56 --> 00:39:58 of Mercury's orbit, the wobble of the orbit
00:39:59 --> 00:40:00 wobbling at a slightly different rate. And
00:40:00 --> 00:40:02 uh, nobody could explain that. It led to
00:40:02 --> 00:40:04 people speculating that maybe there's an
00:40:04 --> 00:40:06 unseen planet closer to the sun than Mercury.
00:40:06 --> 00:40:09 Because we'd seen for the planet Uranus that
00:40:09 --> 00:40:10 an unseen planet pulling it around could
00:40:10 --> 00:40:12 change its orbit. And that was Neptune. But
00:40:12 --> 00:40:14 that didn't work. We never found anything.
00:40:14 --> 00:40:17 And it wasn't until Einstein came up with the
00:40:17 --> 00:40:20 general theory of relativity that, as a
00:40:20 --> 00:40:22 byproduct of that, his method for
00:40:22 --> 00:40:25 understanding how gravity works accurately
00:40:25 --> 00:40:26 Models the precession of Mercury's orbit With
00:40:26 --> 00:40:29 incredible precision. So when Newton came up
00:40:29 --> 00:40:32 with his ideas, the predictions you
00:40:32 --> 00:40:35 would make with Newton's gravity Were so
00:40:35 --> 00:40:37 accurate that it was only 150 years or so
00:40:37 --> 00:40:39 before our observations got good enough to
00:40:39 --> 00:40:41 show that Newton's theories were wrong. They
00:40:41 --> 00:40:44 disproved those theories, but we still use
00:40:44 --> 00:40:46 them because they are so accurate. They're
00:40:46 --> 00:40:48 slightly off, but they're so accurate and
00:40:48 --> 00:40:50 easy to use that they're easier for me to use
00:40:50 --> 00:40:53 in my modeling than general relativity, when
00:40:53 --> 00:40:55 the uncertainties in the things I model are
00:40:55 --> 00:40:57 so great that the difference between those
00:40:57 --> 00:40:59 two is lost in the noise. So it's just easier
00:40:59 --> 00:41:01 for me to use Newton's laws. But it's a
00:41:01 --> 00:41:03 really good example of how theory makes
00:41:03 --> 00:41:05 predictions that are verified for a very long
00:41:05 --> 00:41:08 time. But eventually you get to the point
00:41:08 --> 00:41:10 where you go beyond what theory explains,
00:41:11 --> 00:41:13 and that leads to new theories. And in this
00:41:13 --> 00:41:14 case, it's a case where there are these set
00:41:14 --> 00:41:17 of theories that, uh, are very much at the
00:41:17 --> 00:41:19 cutting edge of science, where the
00:41:19 --> 00:41:21 predictions that they make are predictions of
00:41:21 --> 00:41:24 things we have not yet seen. Because it's
00:41:24 --> 00:41:25 fairly pointless to only predict the things
00:41:25 --> 00:41:27 we have seen and not go beyond that. So they
00:41:27 --> 00:41:30 predict things we haven't yet seen. One of
00:41:30 --> 00:41:32 those things is the existence of cosmogenic
00:41:32 --> 00:41:35 neutrinos. And, um, it may well be that this
00:41:35 --> 00:41:37 is the first detection of a cosmogenic
00:41:37 --> 00:41:39 neutrino, which then adds credence to the
00:41:39 --> 00:41:42 idea that these quantum field theories work
00:41:42 --> 00:41:44 and make sense. So it's that interplay
00:41:44 --> 00:41:46 between theory and observation, an experiment
00:41:46 --> 00:41:49 that I think is really interesting, Even if,
00:41:49 --> 00:41:51 to be honest, I really don't understand it.
00:41:51 --> 00:41:54 Andrew Dunkley: And what, uh, Jonti is saying, Casey, is that
00:41:54 --> 00:41:56 it'll be 150 years before someone comes up
00:41:56 --> 00:41:59 with a model that actually explains it.
00:42:00 --> 00:42:01 Possibly it could happen that way. You never
00:42:01 --> 00:42:04 know. Uh, and thanks for the question. Casey
00:42:04 --> 00:42:07 and I assumed female, but, um, looking at the
00:42:07 --> 00:42:10 spelling of Casey could be male. Apologies if
00:42:10 --> 00:42:11 I got that the wrong way around.
00:42:14 --> 00:42:17 Jonti Horner: Roger, your lots are here. Also space nuts.
00:42:17 --> 00:42:20 Andrew Dunkley: Our final question today comes from young
00:42:20 --> 00:42:21 Henrik.
00:42:21 --> 00:42:24 Jonti Horner: Hello, It's Henrique from Portugal again.
00:42:25 --> 00:42:28 This time I'd like to ask about the
00:42:28 --> 00:42:30 object NWC, uh,
00:42:31 --> 00:42:34 349A. What makes it so
00:42:34 --> 00:42:36 extreme? How does it emit
00:42:36 --> 00:42:39 lasers and lasers. Can you
00:42:39 --> 00:42:42 explain to my dad what's masers are?
00:42:42 --> 00:42:43 Thank you. Bye.
00:42:44 --> 00:42:45 Andrew Dunkley: Thank you. Henrik. Uh, yes,
00:42:45 --> 00:42:48 MWC349A.A for Apple
00:42:48 --> 00:42:51 M, not eight. That's what I thought he said.
00:42:51 --> 00:42:53 But um, yeah, this is ah, this is a,
00:42:54 --> 00:42:57 a mysterious emission line star and
00:42:57 --> 00:42:59 radio bright object in the constellation of
00:42:59 --> 00:43:00 Cygnus.
00:43:00 --> 00:43:01 Jonti Horner: Yes.
00:43:01 --> 00:43:04 Andrew Dunkley: And it's um, it's, it's suffered an intensive
00:43:05 --> 00:43:06 mass loss.
00:43:06 --> 00:43:09 Jonti Horner: Yeah, it's a really interesting object. Now I
00:43:09 --> 00:43:11 wasn't familiar with this object before the
00:43:11 --> 00:43:13 question came in and it's probably something
00:43:13 --> 00:43:15 that when I was Henrik's age, I'd have heard
00:43:15 --> 00:43:17 of and come across and would have really
00:43:17 --> 00:43:19 found fascinating, just like Henrik does.
00:43:19 --> 00:43:22 It's fabulous question as best we
00:43:22 --> 00:43:24 understand that this is something that is a
00:43:24 --> 00:43:26 very luminous, very bright star,
00:43:27 --> 00:43:30 much younger than the Sun. It's probably at
00:43:30 --> 00:43:32 most 5 million years old. But it could either
00:43:32 --> 00:43:34 be a baby star that's still forming
00:43:34 --> 00:43:36 or a very massive star that's just coming to
00:43:36 --> 00:43:38 the end of its life, even though it's only 5
00:43:38 --> 00:43:40 million years old. And there's been a lot of
00:43:40 --> 00:43:42 debate of that over the years. It
00:43:42 --> 00:43:45 is famous and it's prominent because it's one
00:43:45 --> 00:43:48 of the most bright things in the sky at uh,
00:43:48 --> 00:43:50 millimeter and radio wavelengths. It's very,
00:43:50 --> 00:43:52 very bright, very obviously visible, even
00:43:52 --> 00:43:54 though it's way too faint to see with the
00:43:54 --> 00:43:57 naked eye. Part of the reason it's too faint
00:43:57 --> 00:43:58 to see with the naked eye though, is that
00:43:58 --> 00:44:00 there's a lot of dust and gas around both
00:44:01 --> 00:44:03 where the object is. We found that it's got a
00:44:04 --> 00:44:06 disk of dust and gas around it. Let's edge
00:44:06 --> 00:44:08 onto us and is blocking some of the light.
00:44:08 --> 00:44:10 Plus it's in the spiral arm of the Milky Way,
00:44:10 --> 00:44:12 so there's a lot of dust and gas between us.
00:44:12 --> 00:44:14 So this thing has an apparent magnitude of
00:44:14 --> 00:44:17 about 13, but there are about 10
00:44:17 --> 00:44:19 magnitudes of extinction along the line of
00:44:19 --> 00:44:21 sight between us and it, which means that for
00:44:21 --> 00:44:23 every 10 photons it emits, only one
00:44:23 --> 00:44:25 reaches us. In other words, if you could
00:44:25 --> 00:44:28 clear all the dust and gas out, this will be
00:44:28 --> 00:44:29 a third magnitude star and easy to see with a
00:44:29 --> 00:44:30 naked eye.
00:44:30 --> 00:44:31 Andrew Dunkley: Right.
00:44:31 --> 00:44:33 Jonti Horner: So that's intrinsically how luminous it is.
00:44:33 --> 00:44:35 It's thought to be about 1300 parsecs away.
00:44:35 --> 00:44:38 So that's 39004000 light years. So
00:44:38 --> 00:44:41 the light we receive from it we're seeing it
00:44:41 --> 00:44:43 how it was 4 years ago when that light
00:44:43 --> 00:44:45 was emitted. And because it's so
00:44:45 --> 00:44:48 luminous in radio wavelengths, it's been
00:44:48 --> 00:44:51 fairly well studied. And in particular, it
00:44:51 --> 00:44:53 gives off a lot of energy at, uh, wavelengths
00:44:53 --> 00:44:56 linked to molecular hydrogen. And it's known
00:44:56 --> 00:44:59 as one of the few hydrogen masers that we see
00:44:59 --> 00:45:01 in the sky. Which leads to Henrik's question
00:45:01 --> 00:45:04 about what is a maser? The very
00:45:04 --> 00:45:05 simple answer to that, which doesn't tell you
00:45:05 --> 00:45:08 anything, is that a maser is a laser,
00:45:08 --> 00:45:10 but happening at millimeter wavelengths. So
00:45:10 --> 00:45:13 in the infrared, on radio. But it's the
00:45:13 --> 00:45:15 same physical process. And in fact, masers
00:45:15 --> 00:45:17 were what we developed before we could do
00:45:17 --> 00:45:20 lasers, because lasers are the same
00:45:20 --> 00:45:22 phenomenon happening at visible wavelengths
00:45:22 --> 00:45:24 in the optical. That is a very accurate
00:45:24 --> 00:45:26 description that tells you actually nothing
00:45:26 --> 00:45:28 about what's going on. And I dug into this a
00:45:28 --> 00:45:30 bit because like a lot of people, I use
00:45:30 --> 00:45:32 lasers and think about them, but never really
00:45:33 --> 00:45:35 remind myself how they work. Laser
00:45:35 --> 00:45:38 stands for light activated.
00:45:39 --> 00:45:42 Um, Simulated Emission of radiation.
00:45:42 --> 00:45:44 Sorry, Light Amplification by Simulated
00:45:44 --> 00:45:46 Emission of radiation. It's an acronym. And
00:45:46 --> 00:45:49 MESA stands for Microwave Amplification by
00:45:49 --> 00:45:51 Stimulated Emission of Radiation. So it's the
00:45:51 --> 00:45:53 same process just happening at longer
00:45:53 --> 00:45:56 wavelengths. What's happening effectively is
00:45:56 --> 00:45:58 that when atoms are
00:45:59 --> 00:46:01 excited, when energy is pumped into atoms
00:46:02 --> 00:46:04 and that energy is absorbed by them, it makes
00:46:04 --> 00:46:06 the electrons in those atoms jump from one
00:46:06 --> 00:46:09 level to a higher energy level. And they are
00:46:09 --> 00:46:12 very specific jumps in energy. It can only
00:46:12 --> 00:46:14 jump by a certain amount. It can't miss a
00:46:14 --> 00:46:16 gap. It's got to get exactly the right jump
00:46:16 --> 00:46:19 to jump from one level to the next. So those
00:46:19 --> 00:46:21 energy levels have very specific wavelengths
00:46:21 --> 00:46:22 and we actually calculate them at
00:46:22 --> 00:46:24 universities, part of our undergrad quantum
00:46:24 --> 00:46:26 mechanics courses and things like this. It's
00:46:26 --> 00:46:28 one of the tasks you have is work out the
00:46:28 --> 00:46:30 energy levels of a hydrogen atom and
00:46:30 --> 00:46:33 they are quantized such that, uh, when you're
00:46:33 --> 00:46:35 at an energy level, if you want to jump down
00:46:35 --> 00:46:36 to another one, you can only do that by
00:46:36 --> 00:46:39 emitting a single photon. You can't emit
00:46:39 --> 00:46:41 multiple photons that add up to that level.
00:46:41 --> 00:46:43 You can only emit one photon. And you have to
00:46:43 --> 00:46:46 hit the right energy level to get the gap.
00:46:47 --> 00:46:49 And so that's why excited hydrogen glows at
00:46:49 --> 00:46:52 very specific colors. So the photo behind me,
00:46:52 --> 00:46:54 which won't be visible if you're listening to
00:46:54 --> 00:46:56 this as a podcast, but the photo behind me
00:46:56 --> 00:46:58 shows the Helix Nebula, which is a star
00:46:58 --> 00:47:01 forming, sorry, the Trifid Nebula, which, uh,
00:47:01 --> 00:47:03 is a star forming region in the middle of
00:47:03 --> 00:47:05 It's a very distinctive pink color. And that
00:47:05 --> 00:47:08 pink color is hydrogen alpha emission, which,
00:47:08 --> 00:47:10 which is hydrogen atoms jumping from the
00:47:10 --> 00:47:13 third energy level to the second, emitting
00:47:13 --> 00:47:15 light, and all emitting light of exactly the
00:47:15 --> 00:47:17 same color. So that's known as
00:47:17 --> 00:47:20 spontaneous emission. That's where the atom
00:47:20 --> 00:47:22 sheds its energy by emitting light of a
00:47:22 --> 00:47:25 certain color. Simulated emission is where
00:47:25 --> 00:47:27 something happens to trigger that emission,
00:47:28 --> 00:47:30 specifically at a specific time. So you've
00:47:30 --> 00:47:33 got an atom, um, that is excited, is sat at a
00:47:33 --> 00:47:35 higher energy level, and something gives it a
00:47:35 --> 00:47:38 nudge and causes it to emit energy. And the
00:47:38 --> 00:47:40 way that that works is that it absorbs a
00:47:40 --> 00:47:42 photon of the same energy of the energy level
00:47:42 --> 00:47:45 difference that it was going to emit anyway,
00:47:45 --> 00:47:47 and then immediately emits two photons of
00:47:47 --> 00:47:49 that energy. So you get one photon in and two
00:47:49 --> 00:47:52 photons out. Two photons out can hit two
00:47:52 --> 00:47:54 atoms and trigger them to emit, which means
00:47:54 --> 00:47:56 you get four photons out and so on. So you
00:47:56 --> 00:47:59 can get this cascade. So what makes it work
00:47:59 --> 00:48:01 is that there are many ways of exciting the
00:48:01 --> 00:48:03 atoms in the first place. They don't have to
00:48:03 --> 00:48:05 just absorb photons. They can be excited
00:48:05 --> 00:48:07 through magnet magnetic fields, uh, or all
00:48:07 --> 00:48:10 sorts of different things going on. And so a
00:48:10 --> 00:48:12 maser is effectively somewhere where
00:48:13 --> 00:48:15 emission is being stimulated by
00:48:15 --> 00:48:18 incoming photons of a given wavelength, which
00:48:18 --> 00:48:20 results in more photons being emitted of that
00:48:20 --> 00:48:23 wavelength than are coming in. And so you get
00:48:23 --> 00:48:26 this amplification effect. So in this
00:48:26 --> 00:48:27 case, this being a hydrogen maser means that
00:48:27 --> 00:48:30 you've got a lot of hydrogen gas there. That
00:48:30 --> 00:48:32 hydrogen gas is being irradiated by emission
00:48:32 --> 00:48:34 of a specific wavelength by this object.
00:48:35 --> 00:48:37 Um, and that is stimulating the emission of
00:48:37 --> 00:48:39 more photons, which means you get an
00:48:39 --> 00:48:41 extremely bright emission at that wavelength
00:48:41 --> 00:48:43 because you're getting this amplification
00:48:43 --> 00:48:46 effect. And so that's how these things works
00:48:46 --> 00:48:48 as a maser. And that has been very useful in
00:48:48 --> 00:48:50 allowing us to study it because it means we
00:48:50 --> 00:48:52 get a stronger signal, we get more light, so
00:48:52 --> 00:48:53 there's more we can study.
00:48:54 --> 00:48:57 What my research around it this morning
00:48:57 --> 00:48:59 kind of found out was that there is some
00:49:00 --> 00:49:02 significant debate historically over whether
00:49:02 --> 00:49:05 this is firstly a binary star, or on its own,
00:49:05 --> 00:49:07 there's another very hot blue star very close
00:49:07 --> 00:49:10 to it in the sky that for a long time was
00:49:10 --> 00:49:12 thought to be a binary companion. And that's
00:49:12 --> 00:49:15 why this is MWC349A,
00:49:15 --> 00:49:18 because there's a star MWC349B.
00:49:18 --> 00:49:21 Now, recent studies that have measured the
00:49:21 --> 00:49:23 radial velocity of the two stars suggests
00:49:23 --> 00:49:26 that the star B is moving 35
00:49:26 --> 00:49:29 kilometers per second compared to star A. So
00:49:29 --> 00:49:30 they're not gravitationally held together
00:49:30 --> 00:49:32 anymore. So they're probably not now a
00:49:32 --> 00:49:35 binary. Though there is some debate whether
00:49:36 --> 00:49:38 they were in the past, whether they were held
00:49:38 --> 00:49:40 together by gravity. And then those two stars
00:49:40 --> 00:49:42 have shed mass. As we said, this star seems
00:49:42 --> 00:49:45 to have thrown mass away in recent times, may
00:49:45 --> 00:49:47 even have lost half its mass. It may have
00:49:47 --> 00:49:49 gone from 40 solar masses to 20. That
00:49:49 --> 00:49:51 weakens its gravitational pull until
00:49:51 --> 00:49:54 eventually the binary falls apart. So that's
00:49:54 --> 00:49:55 one part of the debate. But the recent
00:49:55 --> 00:49:58 results seem to suggest that even if they
00:49:58 --> 00:49:59 were a binary in the past, they no longer
00:49:59 --> 00:50:02 are. The other debate is
00:50:02 --> 00:50:04 whether this is a very young star that's only
00:50:04 --> 00:50:07 just forming now. Or whether it's a star that
00:50:07 --> 00:50:09 formed a few million years ago and is coming
00:50:09 --> 00:50:11 to the end of its life. And, um, you'd have
00:50:11 --> 00:50:13 thought that was obvious. But for stars like
00:50:13 --> 00:50:15 this, it's quite hard to tell, especially
00:50:15 --> 00:50:17 when they're so obscured by gas and dust.
00:50:17 --> 00:50:20 Now, if it was a baby star, the really
00:50:20 --> 00:50:22 odd part of that would be, why are there no
00:50:22 --> 00:50:25 other baby stars around it? Stars kind of
00:50:25 --> 00:50:27 form in big nurseries. And particularly
00:50:27 --> 00:50:29 massive stars don't tend to form alone. They
00:50:29 --> 00:50:32 tend to form in big associations where lots
00:50:32 --> 00:50:34 of stars are forming at once. And there's one
00:50:34 --> 00:50:37 relatively near this called Cygnus OB2.
00:50:37 --> 00:50:39 And, uh, one of the suggestions for this
00:50:39 --> 00:50:41 star, if it's an older star that's coming to
00:50:41 --> 00:50:43 the end of its life, is that it formed in
00:50:43 --> 00:50:45 that association and was ejected in an
00:50:45 --> 00:50:46 encounter with other stars and flung
00:50:46 --> 00:50:48 outwards. And, um, we're seeing it quite far
00:50:48 --> 00:50:50 away because it's traveled that distance
00:50:50 --> 00:50:52 through its lifetime. So it formed there, but
00:50:52 --> 00:50:55 it's escaped. If it's a baby
00:50:55 --> 00:50:57 star, we have the problem of how is it only
00:50:57 --> 00:50:59 just forming in an area where there's not
00:50:59 --> 00:51:01 really any other stars forming around it.
00:51:01 --> 00:51:03 Recent studies have suggested, by looking
00:51:04 --> 00:51:07 over all things, the balance between carbon
00:51:07 --> 00:51:09 13 and carbon 12, these two different carbon
00:51:09 --> 00:51:12 isotopes in the gas that has been shed by
00:51:12 --> 00:51:15 this star. Recent, uh, measurements of that
00:51:15 --> 00:51:17 have suggested it's actually an old star.
00:51:18 --> 00:51:20 Well, old for its mass, you know, about 5
00:51:20 --> 00:51:22 million years old. But coming to the end of
00:51:22 --> 00:51:25 its life, that has been shedding mass. And,
00:51:25 --> 00:51:27 um, that is explained by the balance of the
00:51:27 --> 00:51:29 isotopes in the gases that it has emitted.
00:51:29 --> 00:51:31 Which fits in a bit better with the idea that
00:51:31 --> 00:51:33 it may have formed in that Cygnus LB2
00:51:33 --> 00:51:35 association a few million years ago, have
00:51:35 --> 00:51:38 been flung outwards and escaped. Would also
00:51:38 --> 00:51:40 fit A little bit with the idea that the star,
00:51:40 --> 00:51:43 uh, B next to it, was once held to it as a
00:51:43 --> 00:51:45 binary. But with the mass loss, they've
00:51:45 --> 00:51:46 separated and they're going their separate
00:51:46 --> 00:51:49 ways. You know, that happens all the time.
00:51:49 --> 00:51:51 And so that all kind of, as a narrative seems
00:51:51 --> 00:51:53 to fit together. But it's got a disk of
00:51:53 --> 00:51:55 material around it that's nearly edge on.
00:51:55 --> 00:51:57 It's got jets of material coming out of it.
00:51:57 --> 00:51:59 There is a suggestion that it's probably shed
00:52:00 --> 00:52:02 something like 20 times the mass of the sun
00:52:02 --> 00:52:03 over the last few hundred thousand years.
00:52:04 --> 00:52:06 And, uh, that it's shedding something like
00:52:06 --> 00:52:09 1/100th of a solar mass per year,
00:52:10 --> 00:52:12 which doesn't sound like a lot, but that's a
00:52:12 --> 00:52:14 huge amount of mass to be throwing away in
00:52:14 --> 00:52:16 every given year, which means it would throw
00:52:16 --> 00:52:18 away a mass equ, the mass of the sun in just
00:52:18 --> 00:52:21 100 years. That's really significant
00:52:21 --> 00:52:23 mass loss going on as this star comes to the
00:52:23 --> 00:52:25 end of its life. And it's a really
00:52:25 --> 00:52:28 interesting case study of that detective
00:52:28 --> 00:52:31 story again, of how we gather clues from
00:52:31 --> 00:52:33 all these different types of observations
00:52:33 --> 00:52:36 about a star that for us, at optical
00:52:36 --> 00:52:38 wavelengths is so heavily concealed from us
00:52:38 --> 00:52:41 that only one part in 10 of the light it
00:52:41 --> 00:52:43 emits actually reaches as the rest of it gets
00:52:43 --> 00:52:45 absorbed en route. Um, and that's why it's
00:52:45 --> 00:52:47 been such a challenging problem for astronomy
00:52:47 --> 00:52:49 for so many years, because it's really hard
00:52:49 --> 00:52:52 to see what's going on. But by looking at the
00:52:52 --> 00:52:54 masers emitting this light, by looking at all
00:52:54 --> 00:52:56 the different things going on around it, by
00:52:56 --> 00:52:59 doing clever studies of the chemistry of the
00:52:59 --> 00:53:01 gases around it, we can start to piece
00:53:01 --> 00:53:03 together its life story and figure out what
00:53:03 --> 00:53:05 it is. I don't think that story of
00:53:05 --> 00:53:08 discovery is finished yet, by any means. And
00:53:08 --> 00:53:09 it may well be, Henrik, that when you're
00:53:09 --> 00:53:11 older, you can actually work on this object
00:53:11 --> 00:53:13 and learn more about it yourself. I suspect
00:53:13 --> 00:53:15 people will still be discovering things about
00:53:15 --> 00:53:18 this object in decades to come. But
00:53:18 --> 00:53:20 it's a really fascinating object, and I'm
00:53:20 --> 00:53:22 just so delighted that you brought it to my
00:53:22 --> 00:53:23 attention because I'd never stumbled across
00:53:23 --> 00:53:25 it before, and it's really, really cool.
00:53:25 --> 00:53:27 Andrew Dunkley: Yes, it's, um. Sorry for this. It's
00:53:27 --> 00:53:30 amazing. Uh, but, Henrik, thanks for the
00:53:30 --> 00:53:33 question, and you do sound, uh, very astute,
00:53:33 --> 00:53:35 and maybe, maybe you will be the one that
00:53:35 --> 00:53:37 will solve it in years to come. Lovely to
00:53:37 --> 00:53:40 hear from you. And if you have questions for
00:53:40 --> 00:53:43 us, please send them through. We can take,
00:53:43 --> 00:53:44 uh, your questions on our website. So, Space
00:53:44 --> 00:53:47 Nuts podcast.com spacenuts IO
00:53:48 --> 00:53:51 click on that little AMA link up the top
00:53:51 --> 00:53:53 and you can send us text or audio
00:53:53 --> 00:53:55 questions or both. Some people have done
00:53:55 --> 00:53:57 that. And don't forget to tell us who you are
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00:53:59 --> 00:54:02 kind of running sort of
00:54:02 --> 00:54:05 parallel with the number of questions we need
00:54:05 --> 00:54:07 each week. So, uh, we haven't got a big
00:54:07 --> 00:54:09 stockpile at the moment. So it's a good time
00:54:09 --> 00:54:12 to send some questions into us. So please do.
00:54:12 --> 00:54:14 Would love to hear from you. Don't even worry
00:54:14 --> 00:54:17 if you think it's dumb, because there's no
00:54:17 --> 00:54:19 dumb questions in astronomy and space
00:54:19 --> 00:54:21 science. There's weird questions, but there
00:54:21 --> 00:54:24 aren't any dumb questions. And, uh, while
00:54:24 --> 00:54:25 you're on our website, have a look around.
00:54:26 --> 00:54:28 There's a little link, uh, shop
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00:54:36 --> 00:54:38 uh, you are interested in becoming a patron,
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00:54:44 --> 00:54:46 Uh, those are just options. None of it's
00:54:46 --> 00:54:49 mandatory. And, uh, we appreciate all the
00:54:49 --> 00:54:52 support we get, so thank you. And Jonti,
00:54:52 --> 00:54:54 thank you so much. Uh, it's been great to
00:54:54 --> 00:54:56 talk to you and, uh, we'll see you on the
00:54:56 --> 00:54:56 next episode.
00:54:57 --> 00:54:58 Jonti Horner: Yeah. Thank you for having me. It's good to
00:54:58 --> 00:54:59 be back.
00:54:59 --> 00:55:01 Andrew Dunkley: Always a pleasure. Jonti, uh, Horner,
00:55:01 --> 00:55:03 professor of Astrophysics at the University
00:55:03 --> 00:55:05 of Southern Queensland. And, uh, uh, thanks
00:55:05 --> 00:55:08 to Huw in the studio who, um,
00:55:08 --> 00:55:11 couldn't be with us today because they're
00:55:11 --> 00:55:13 going to hate me for this one. He got lost in
00:55:13 --> 00:55:16 a maser. Oh, dear. And from me, Andrew
00:55:16 --> 00:55:18 Dunkley. Thanks for your company. We'll see
00:55:18 --> 00:55:20 you on the next episode of Space Nuts. Bye.
00:55:20 --> 00:55:20 Bye.
00:55:21 --> 00:55:23 Voice Over Guy: You've been listening to the Space Nuts
00:55:23 --> 00:55:26 podcast, available at
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00:55:29 --> 00:55:31 iHeartRadio, or your favorite podcast
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00:55:36 --> 00:55:38 quality podcast production from
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