In this engaging Q&A episode of Space Nuts, hosts Andrew Dunkley and Professor Jonti Horner tackle a range of thought-provoking questions from listeners. From the effects of light pollution on stargazing to the intriguing concept of a space parasol for climate control, this episode is packed with cosmic curiosities and insightful discussions that will leave you contemplating the future of humanity in space.
Episode Highlights:
- Light Pollution and Night Sky Visibility: Mark from Connecticut wonders how quickly the night sky would become visible if all electric lights suddenly went out. Andrew and Jonti discuss the immediate effects of light pollution and the importance of dark adaptation for optimal stargazing, emphasizing the impact of atmospheric conditions on visibility.
- Geoengineering and Space Parasols: Doug raises the question of whether a parasol at Lagrange Point 1 could help mitigate climate change. The hosts explore the feasibility of such a project, discussing the challenges of scale, technology, and the implications of geoengineering on the Earth's climate system.
- Salvage Rights in Space: A listener inquires about the ownership of defunct satellites and the potential for salvage rights in space. Andrew and Jonti explain the current legal landscape surrounding space debris, the challenges of recovery, and the evolving nature of space law as commercial interests grow.
- Searching for Extraterrestrial Life: Robert from the Netherlands asks about the role of radio waves in searching for alien civilizations. The hosts delve into the efforts of the SETI program, the challenges of detecting signals, and the potential of the Square Kilometer Array to listen for extraterrestrial communications.
For more Space Nuts, including our continuously updating newsfeed and to listen to all our episodes, visit our website. Follow us on social media at SpaceNutsPod on Facebook, X, YouTube Music Music, Tumblr, Instagram, and TikTok. We love engaging with our community, so be sure to drop us a message or comment on your favorite platform.
If you’d like to help support Space Nuts and join our growing family of insiders for commercial-free episodes and more, visit spacenutspodcast.com/about.
Stay curious, keep looking up, and join us next time for more stellar insights and cosmic wonders. Until then, clear skies and happy stargazing.
Become a supporter of this podcast: https://www.spreaker.com/podcast/space-nuts-astronomy-insights-cosmic-discoveries--2631155/support.
00:00:00 --> 00:00:00 Jonti Horner: Hi there.
00:00:00 --> 00:00:02 Andrew Dunkley: Thanks for joining us on Space Nuts Q and A
00:00:02 --> 00:00:04 edition. This is where the audience sets the
00:00:04 --> 00:00:06 agenda, and we answer the questions to the
00:00:06 --> 00:00:08 best of our ability, which is not much
00:00:08 --> 00:00:11 ability at all, but we'll do it anyway. Uh,
00:00:11 --> 00:00:13 coming up, questions about light pollution.
00:00:13 --> 00:00:16 A, uh, space parasol to protect
00:00:16 --> 00:00:19 Earth. Interesting. Uh, also salvage
00:00:19 --> 00:00:21 rights in space and radio waves.
00:00:22 --> 00:00:24 That's all coming up on space nuts.
00:00:24 --> 00:00:27 15 seconds. Guidance is internal.
00:00:27 --> 00:00:30 10, 9, ignition
00:00:30 --> 00:00:33 sequence. Star nuts. 5, 4,
00:00:33 --> 00:00:36 3, 2. 1, 2, 3, 4, 5, 5, 4,
00:00:36 --> 00:00:37 3, 2, 1.
00:00:37 --> 00:00:38 Jonti Horner: Space nuts.
00:00:38 --> 00:00:41 Andrew Dunkley: Astronauts report it feels good. And
00:00:41 --> 00:00:43 he's back again. Professor Jonti Horner,
00:00:43 --> 00:00:45 professor of Astrophysics at the University
00:00:45 --> 00:00:47 of Southern Queensland. Jonti. Hi there.
00:00:48 --> 00:00:49 Jonti Horner: Good afternoon. How are you going?
00:00:49 --> 00:00:52 Andrew Dunkley: I am well. Want to get
00:00:52 --> 00:00:53 straight into it?
00:00:53 --> 00:00:55 Jonti Horner: Yeah, let's dive on in.
00:00:55 --> 00:00:57 Andrew Dunkley: Okay. Question time. And our, uh, first
00:00:57 --> 00:00:59 question comes from Mark.
00:01:00 --> 00:01:02 He says, hello. I have a question about light
00:01:02 --> 00:01:05 pollution. I live in Connecticut, and the
00:01:05 --> 00:01:07 light pollution is not as bad as New York
00:01:07 --> 00:01:10 City, but it is enough. I'm planning a trip
00:01:10 --> 00:01:12 to Montana this summer just to see the night
00:01:12 --> 00:01:15 sky. My question is, if I was standing
00:01:15 --> 00:01:18 in my yard and there was a sudden EMP
00:01:18 --> 00:01:20 burst and all the electric lights went out,
00:01:20 --> 00:01:23 how long would it take for me to be able to
00:01:23 --> 00:01:26 see the night sky in Connecticut as clear and
00:01:26 --> 00:01:29 as. As beautiful as Point Nemo? I understand
00:01:29 --> 00:01:31 light speed is fast, but how fast
00:01:32 --> 00:01:35 would it be to clear the view? I've
00:01:35 --> 00:01:37 just, uh, recently discovered your podcast. I
00:01:37 --> 00:01:40 learned something new with each uh, one.
00:01:40 --> 00:01:42 Uh, please keep up the outstanding work. I
00:01:42 --> 00:01:45 look forward to every new episode.
00:01:45 --> 00:01:47 Sincerely, Mark Bookbinder. Thank you,
00:01:47 --> 00:01:49 Mark. That's a lovely comment. Uh, we don't
00:01:49 --> 00:01:51 get many nice comments. Everyone's usually
00:01:51 --> 00:01:53 sticking the knife in. No, I'm not kidding.
00:01:53 --> 00:01:56 Most people, uh, are terrific. Um,
00:01:56 --> 00:01:58 although we get the occasional jibe, but that
00:01:58 --> 00:02:01 goes with the territory. Um,
00:02:01 --> 00:02:04 yeah, look, I. I had a think about this one,
00:02:04 --> 00:02:06 and I. I would suggest.
00:02:07 --> 00:02:09 I don't want to steal your thunder, Jonti,
00:02:09 --> 00:02:10 because I know you've done your homework, but
00:02:10 --> 00:02:12 I would suggest that it would be fairly
00:02:12 --> 00:02:15 instantaneous because the amount of light
00:02:15 --> 00:02:17 coming down would be the same.
00:02:18 --> 00:02:20 It's just that it's disturbed by the light
00:02:20 --> 00:02:23 we're sending up. So when that light we are
00:02:23 --> 00:02:26 creating suddenly disappeared, surely
00:02:26 --> 00:02:28 the effect would be an instant
00:02:29 --> 00:02:31 view of what's really happening up there.
00:02:32 --> 00:02:34 Jonti Horner: Effectively, I think that's pretty much it.
00:02:34 --> 00:02:37 Um, uh, now, there's a few
00:02:37 --> 00:02:38 things that fall into that, and that's a
00:02:38 --> 00:02:41 really good kind of executive summary type
00:02:41 --> 00:02:43 level. So the reason that Light pollution is
00:02:43 --> 00:02:45 a problem for you. Seeing the night sky and
00:02:45 --> 00:02:48 all its wonder is you're basically increasing
00:02:48 --> 00:02:50 the brightness of the whole sky by an
00:02:50 --> 00:02:52 artificial amount which washes out the
00:02:52 --> 00:02:55 fine detail of the darker, the fainter stuff.
00:02:55 --> 00:02:57 So the brighter your light pollution levels
00:02:57 --> 00:02:59 are, uh, the brighter the sky is and so the
00:02:59 --> 00:03:01 fewer faint objects you can see and the more
00:03:01 --> 00:03:03 you brighten that, the less you'll see. If
00:03:03 --> 00:03:06 you turn all the lights off at once, the sky
00:03:06 --> 00:03:09 will almost instantaneously become as dark
00:03:09 --> 00:03:12 as it could possibly be. And then what's
00:03:12 --> 00:03:14 working against you is the adaptation of your
00:03:14 --> 00:03:17 eye. So we have this thing called dark
00:03:17 --> 00:03:20 adaptation and m, it's how our eye
00:03:20 --> 00:03:22 adjusts and responds to low light levels to
00:03:22 --> 00:03:24 allow us to function in those levels
00:03:24 --> 00:03:27 effectively. And you get the bulk of
00:03:27 --> 00:03:29 your dark adaption within about the first
00:03:29 --> 00:03:32 five minutes. But your eyes continue
00:03:32 --> 00:03:34 adapting and getting better and better at
00:03:34 --> 00:03:37 seeing in the dark over about
00:03:37 --> 00:03:40 45 minute period. So you have to be out under
00:03:40 --> 00:03:42 the night sky and avoid looking at any
00:03:42 --> 00:03:44 sources of bright light for about 45
00:03:44 --> 00:03:46 minutes before you're as adapted as you can
00:03:46 --> 00:03:49 be and you can get the best possible view you
00:03:49 --> 00:03:52 can get. Now what would happen is if you
00:03:52 --> 00:03:54 were out and about in your sadly light
00:03:54 --> 00:03:56 polluted skies in Connecticut, um,
00:03:57 --> 00:03:59 you are um, not very well dark adapted
00:03:59 --> 00:04:02 because the sky is very bright. So your clock
00:04:02 --> 00:04:04 would have to start ticking from the point
00:04:04 --> 00:04:05 the lights went out. So I would hope that the
00:04:05 --> 00:04:07 lights stared out for at least an hour for
00:04:07 --> 00:04:10 you to give you the best possible view. But
00:04:10 --> 00:04:12 even then you might not get the best view of
00:04:12 --> 00:04:13 the night sky you could anywhere on Earth,
00:04:13 --> 00:04:15 because you then run into the issues of the
00:04:15 --> 00:04:18 Earth's atmosphere. Um, now I
00:04:18 --> 00:04:20 regularly go out to the wonderful Lady
00:04:20 --> 00:04:22 Elliott island on the Barrier Reef where
00:04:22 --> 00:04:24 there's effectively no light pollution at all
00:04:24 --> 00:04:26 and the sky is dark enough that for example,
00:04:26 --> 00:04:29 I can see the Triangulum galaxy, which is
00:04:29 --> 00:04:31 fainter than Andromeda. I can see pretty much
00:04:31 --> 00:04:33 every time I go out there there's a darker
00:04:33 --> 00:04:36 light and um, I lead guessing
00:04:36 --> 00:04:38 some stargazing there and m tell them how
00:04:38 --> 00:04:40 awesome the sky is. But I make the point that
00:04:40 --> 00:04:41 if they were to go to the centre of
00:04:41 --> 00:04:44 Australia, to somewhere like Uluru or out
00:04:44 --> 00:04:46 into the Nullarborg Desert, they'd actually
00:04:46 --> 00:04:49 see a better sky there than we see at Lady
00:04:49 --> 00:04:51 Elliot. Because at Lady Elliot you have a
00:04:51 --> 00:04:52 limitation that you're surrounded by very
00:04:52 --> 00:04:55 humid, very turbulent air because of the
00:04:55 --> 00:04:57 energy from the ocean stirring the air up.
00:04:57 --> 00:05:00 And so different locations on the Earth offer
00:05:00 --> 00:05:02 different clarity of the night sky.
00:05:03 --> 00:05:06 So what I'd suggest is from Connecticut,
00:05:06 --> 00:05:08 I've got the light pollution map up here,
00:05:08 --> 00:05:10 which, um, is light pollutionmap.info for
00:05:10 --> 00:05:12 people who want to look and weep at how bad
00:05:12 --> 00:05:15 the skies are from their location and plan
00:05:15 --> 00:05:17 their dark sky holidays. That's a really nice
00:05:17 --> 00:05:20 little website. You're relatively coastal
00:05:20 --> 00:05:21 and so therefore your air is going to be
00:05:21 --> 00:05:23 quite humid and turbulent. And I would
00:05:23 --> 00:05:25 suggest if you turned, turned all the lights
00:05:25 --> 00:05:28 on the earth off, that you would have an
00:05:28 --> 00:05:31 experience probably comparable to what we get
00:05:31 --> 00:05:33 in coastal Australia. Whereas if you went
00:05:33 --> 00:05:35 deep into the inland and you got a really
00:05:35 --> 00:05:38 dark sky and be better if you then went
00:05:38 --> 00:05:40 to higher ground, like perhaps in Arizona,
00:05:40 --> 00:05:43 which I understand is a quite high altitude
00:05:43 --> 00:05:45 desert. If you're at higher altitude
00:05:46 --> 00:05:49 there is less air, so therefore there is
00:05:49 --> 00:05:52 less muck and you get a better sky. But
00:05:52 --> 00:05:53 that's balanced by the fact that if you're at
00:05:53 --> 00:05:55 high enough altitude, you're not getting as
00:05:55 --> 00:05:57 much oxygen and you don't see as effectively.
00:05:57 --> 00:05:59 So I've had stories from colleagues of mine
00:05:59 --> 00:06:01 who've been up to the great observatories,
00:06:02 --> 00:06:05 um, in the Andes, in Chile and also up
00:06:05 --> 00:06:07 in Hawaii who've gone out on a night and
00:06:07 --> 00:06:08 they've initially been quite disappointed
00:06:08 --> 00:06:10 that they didn't see a sky quite as
00:06:10 --> 00:06:12 expensive, as spectacular as they thought
00:06:12 --> 00:06:14 they would do. And people on Hawaii actually
00:06:14 --> 00:06:16 will often have a little bowl of oxygen and
00:06:16 --> 00:06:19 have an inhale to increase their blood oxygen
00:06:19 --> 00:06:21 levels, to increase the response of their
00:06:21 --> 00:06:24 eyes to counter the thinner atmosphere and
00:06:24 --> 00:06:26 then they get a really spectacular view.
00:06:26 --> 00:06:26 Andrew Dunkley: Wow.
00:06:27 --> 00:06:29 Jonti Horner: So, like most questions, there's a very
00:06:29 --> 00:06:31 simple answer which is as soon as the light
00:06:31 --> 00:06:34 goes out, you'll get a really good view, but
00:06:34 --> 00:06:36 that view will get better as your eyes adjust
00:06:36 --> 00:06:38 to the darkness. But how good of you you get
00:06:39 --> 00:06:41 is not just dependent on the light pollution,
00:06:41 --> 00:06:42 you'll start to bring in other effects. And
00:06:42 --> 00:06:45 my hope would be that the EMP burst and the
00:06:45 --> 00:06:47 end of all street lighting would happen at
00:06:47 --> 00:06:50 new moon rather than full moon. Because if
00:06:50 --> 00:06:52 you've got a full moon in the sky, all those
00:06:52 --> 00:06:54 effects of humidity and dust are exacerbated.
00:06:55 --> 00:06:57 And even with all the lights turned off, the
00:06:57 --> 00:06:58 night sky at full moon is a bit
00:06:58 --> 00:07:00 disappointing. You know, if I could do one
00:07:00 --> 00:07:01 astronomical thing as a kind of great
00:07:01 --> 00:07:04 celestial dictator, I get rid of the moon.
00:07:04 --> 00:07:05 It's just a pen in the backside. It's always
00:07:05 --> 00:07:07 in the way when I want to take photos and
00:07:07 --> 00:07:09 stops me seeing the more interesting things.
00:07:09 --> 00:07:12 It's like um, or lock it into a kind of one
00:07:12 --> 00:07:14 to one orbit with the Earth's orbit around
00:07:14 --> 00:07:16 the sun. So we only ever see it as a very
00:07:16 --> 00:07:18 thin crescent. So it can be beautiful in the
00:07:18 --> 00:07:20 early evening, then bugger off so I can see
00:07:20 --> 00:07:20 the prettier things.
00:07:21 --> 00:07:23 Andrew Dunkley: I can tell you why that's a problem. It's
00:07:23 --> 00:07:26 because everybody likes mooning in photos.
00:07:26 --> 00:07:27 Jonti Horner: Oh, totally.
00:07:29 --> 00:07:31 Andrew Dunkley: Uh, dear. Uh, um,
00:07:32 --> 00:07:34 um, I just thought about the
00:07:35 --> 00:07:38 physical effect of the light being
00:07:38 --> 00:07:40 turned off. But yeah, I didn't consider the
00:07:40 --> 00:07:43 atmosphere or the location or,
00:07:43 --> 00:07:46 um, or your eyes adjusting. I just had
00:07:46 --> 00:07:48 a look at that light pollution map website
00:07:48 --> 00:07:51 and I've honed in on Duo where I am
00:07:51 --> 00:07:54 now. If I just look at the nearest
00:07:54 --> 00:07:57 towns, yeah, I'd have to go just a bit over
00:07:57 --> 00:08:00 20km out of town to get to a
00:08:00 --> 00:08:02 dark sky area which is not too bad. But if,
00:08:02 --> 00:08:04 if you're in Sydney, forget it.
00:08:05 --> 00:08:07 You're gonna have to drive a few hours.
00:08:07 --> 00:08:10 Jonti Horner: But do yourself a favor and zoom out and then
00:08:10 --> 00:08:13 look at the eastern half of the US or look at
00:08:13 --> 00:08:15 eastern Asia and you'll see why we are so.
00:08:15 --> 00:08:18 Let's go. Yeah. That's why
00:08:18 --> 00:08:21 astro tourism's such a growing thing for us
00:08:21 --> 00:08:23 here in Australia. Because even in the big
00:08:23 --> 00:08:26 cities, you know, I moved to Sydney in 2010
00:08:26 --> 00:08:29 and lived very briefly in a
00:08:29 --> 00:08:31 hotel right in the center of Sydney, the most
00:08:31 --> 00:08:34 light polluted part. But I could still see
00:08:34 --> 00:08:36 the Milky Way from the roof of the hotel
00:08:37 --> 00:08:38 because our skies are so good. There's a
00:08:38 --> 00:08:40 couple of factors there. One is that, uh,
00:08:40 --> 00:08:42 Sydney itself puts out a lot of light, but
00:08:42 --> 00:08:44 there's not much else around. So if you're
00:08:44 --> 00:08:46 looking away from Sydney over towards the
00:08:46 --> 00:08:48 ocean, you're looking towards darker skies.
00:08:48 --> 00:08:51 So that helps. But the other thing is, and
00:08:51 --> 00:08:53 this ties into why we get sunburnt so easily
00:08:53 --> 00:08:55 in Australia, the air is just clearer.
00:08:56 --> 00:08:58 So I moved to Australia and everybody said,
00:08:58 --> 00:08:59 you're going to get burnt by the sun and it's
00:08:59 --> 00:09:02 awful. And my first thought was that's the
00:09:02 --> 00:09:04 ozone hole. Because I thought Australia was
00:09:04 --> 00:09:06 further south because I'm used to our
00:09:06 --> 00:09:09 corrupted maps that show the southern
00:09:09 --> 00:09:10 hemisphere wrong. And so Australia looks like
00:09:10 --> 00:09:12 it's near Antarctica and Australia is
00:09:12 --> 00:09:13 actually near the equator. It's. Yeah, it is.
00:09:14 --> 00:09:16 So it's not the ozone hole at all. But I told
00:09:16 --> 00:09:18 some people it's actually due to the fact
00:09:18 --> 00:09:21 that the air in Australia has a much lower
00:09:21 --> 00:09:23 amount of particulates in than any other
00:09:23 --> 00:09:26 continent to do with what's on the interior
00:09:26 --> 00:09:27 of the continent to do with the fact there's
00:09:27 --> 00:09:29 less pollution. So that means there's less to
00:09:29 --> 00:09:32 scatter the solar uv, which is why we get
00:09:32 --> 00:09:34 higher UV indices and therefore more sunburn.
00:09:34 --> 00:09:37 Um, so it's a quirk of geography rather than
00:09:37 --> 00:09:39 just lots of clear skies, which mean we get
00:09:39 --> 00:09:42 UV indices up to 13 or 14 on a hot
00:09:42 --> 00:09:45 summer's day and basically you fry to a crisp
00:09:45 --> 00:09:46 very, very quickly.
00:09:46 --> 00:09:48 What that means for astronomy though is that,
00:09:48 --> 00:09:50 uh, for a given place with a given, given
00:09:50 --> 00:09:53 amount of lighting, we actually get a better
00:09:53 --> 00:09:55 sky than we would do in other places because
00:09:55 --> 00:09:58 there's less to scatter that light. So that
00:09:58 --> 00:10:00 same amount of lighting has a slightly lower
00:10:00 --> 00:10:02 impact. Um, one of the story that ties into
00:10:02 --> 00:10:04 this that I always remember one of the big
00:10:04 --> 00:10:06 hurricanes probably 20 or 30 years ago
00:10:06 --> 00:10:09 knocked out the power across great swathes
00:10:09 --> 00:10:11 of, I think it was Florida. And many people
00:10:11 --> 00:10:13 saw the Milky Way for the very first time in
00:10:13 --> 00:10:15 their lives. And there was panic. People were
00:10:15 --> 00:10:17 actually calling up, uh, their local police.
00:10:17 --> 00:10:20 Oh, I remember this because they thought that
00:10:20 --> 00:10:22 the aliens were coming because the sky looked
00:10:22 --> 00:10:23 so weird and unusual because there were all
00:10:23 --> 00:10:25 these bright points of light in it and this
00:10:25 --> 00:10:28 weird milky glow going across the sky and ah,
00:10:28 --> 00:10:31 we laugh. But it tells you just how decoupled
00:10:31 --> 00:10:33 people are from something that's been so
00:10:33 --> 00:10:35 wonderfully culturally significant for all of
00:10:35 --> 00:10:37 our history. It's so important to the
00:10:37 --> 00:10:38 traditional owners of the land here in
00:10:38 --> 00:10:41 Australia, but also all around the world who
00:10:41 --> 00:10:42 have this deep and intimate connection to the
00:10:42 --> 00:10:45 night sky. And an event like that
00:10:46 --> 00:10:48 really drills home the damage we've done and
00:10:48 --> 00:10:51 how we've removed this. And I'm always
00:10:51 --> 00:10:53 amazed at the reluctance of people in kind of
00:10:53 --> 00:10:55 groups on social media to accept that light
00:10:55 --> 00:10:58 pollution is a problem because can lay odds
00:10:58 --> 00:10:59 at the same problem who say, don't be grumpy,
00:10:59 --> 00:11:02 we need our lights at night to see would be
00:11:02 --> 00:11:05 really, really unpleasantly happy if we have
00:11:05 --> 00:11:07 the same level of noise pollution. If they
00:11:07 --> 00:11:09 had their neighbors kicking out AC DC at 1am
00:11:09 --> 00:11:12 in the morning, they'd be kicking off to the
00:11:12 --> 00:11:14 council. And it seems that we view light
00:11:14 --> 00:11:17 pollution a lot less seriously than we view
00:11:17 --> 00:11:19 sound pollution or other forms of pollution.
00:11:19 --> 00:11:21 And that's changing a bit. But
00:11:22 --> 00:11:24 there's also an energy source side of it, I
00:11:24 --> 00:11:25 mean this is a bit that always makes my head
00:11:25 --> 00:11:27 hurt is if you're throwing 30% of your light
00:11:27 --> 00:11:30 up into the sky, you're wasting 30% of your
00:11:30 --> 00:11:32 electricity and you're therefore just burning
00:11:32 --> 00:11:35 money. And yeah, I'm sure the energy
00:11:35 --> 00:11:36 companies love that because they get bigger
00:11:36 --> 00:11:39 profits. But doesn't seem a very efficient
00:11:39 --> 00:11:40 way to do things.
00:11:40 --> 00:11:42 Andrew Dunkley: No. And when you look at the map, uh, Eastern
00:11:42 --> 00:11:44 United States, basically all the United
00:11:44 --> 00:11:46 States, but particularly the eastern half.
00:11:46 --> 00:11:49 Western Europe, uh, East Asia,
00:11:49 --> 00:11:52 um, and even the east, uh, eastern
00:11:52 --> 00:11:54 half of South America pretty well just
00:11:55 --> 00:11:58 light pollution. Central. Yeah. But you look
00:11:58 --> 00:12:00 at Australia and um,
00:12:00 --> 00:12:03 parts of North Africa, uh,
00:12:03 --> 00:12:05 Greenland, although it's an ice cap so it
00:12:05 --> 00:12:07 makes it a bit difficult. But uh, even the
00:12:07 --> 00:12:10 um, uh, big areas around Russia
00:12:10 --> 00:12:13 and Siberia, uh, complete darkness.
00:12:13 --> 00:12:16 Which is, you know, very good
00:12:16 --> 00:12:18 place to, to go if you. Well probably not
00:12:18 --> 00:12:21 Russia at the moment but um, good places to
00:12:21 --> 00:12:23 go to look at the sky and in terms of air
00:12:23 --> 00:12:26 quality. Um, they did a test a few years ago
00:12:26 --> 00:12:28 and found that the most pure air in the world
00:12:28 --> 00:12:31 crosses Tasmania and southern
00:12:31 --> 00:12:31 Australia.
00:12:33 --> 00:12:34 Jonti Horner: Which sounds about right. But it is why there
00:12:34 --> 00:12:37 is a growing interest in astro tourism
00:12:37 --> 00:12:39 in Australia. I've spoken to a few people
00:12:39 --> 00:12:42 about this in the last 12 months where local
00:12:42 --> 00:12:43 councils and
00:12:45 --> 00:12:47 different commercial groups are looking at
00:12:47 --> 00:12:49 adding astronomy activities to their
00:12:49 --> 00:12:52 offerings because they're aware that for
00:12:52 --> 00:12:55 people coming in from a lot of our places,
00:12:55 --> 00:12:57 um, that source tourists to Australia. These
00:12:57 --> 00:12:58 are people who've never seen the Milky Way,
00:12:58 --> 00:13:01 who've never seen the night sky properly. And
00:13:01 --> 00:13:03 to them it's this kind of romantic ideal that
00:13:03 --> 00:13:06 they could have a night lying under the stars
00:13:06 --> 00:13:09 and see the Milky Way above them. And that's
00:13:09 --> 00:13:10 just the reality here. You know, I step
00:13:10 --> 00:13:12 outside in my backyard and I see the Milky
00:13:12 --> 00:13:15 Way and that makes it a really big
00:13:15 --> 00:13:17 tourist drawer. And people are cottoning onto
00:13:17 --> 00:13:19 that. And that will then be extra ammunition
00:13:19 --> 00:13:21 for us improving lighting laws in Australia.
00:13:21 --> 00:13:23 Because there's an interest beyond just
00:13:23 --> 00:13:25 astronomers. There's a commercial interest to
00:13:25 --> 00:13:27 drive that. So I think it's a real positive
00:13:27 --> 00:13:29 thing. And um, yeah, we'll see more of it.
00:13:29 --> 00:13:32 But in the meantime, roll on the EMP purse.
00:13:33 --> 00:13:35 Andrew Dunkley: Yes, indeed. Uh, thanks for the question
00:13:35 --> 00:13:37 mark. See what you've done. Good, uh, to hear
00:13:37 --> 00:13:38 from.
00:13:40 --> 00:13:42 Jonti Horner: Roger. Your lab is right here.
00:13:42 --> 00:13:44 Andrew Dunkley: Also Space Nuts. This is Space Nuts with
00:13:44 --> 00:13:46 Andrew Dunkley and Jonti Horner.
00:13:46 --> 00:13:48 Our next question comes from
00:13:48 --> 00:13:50 Doug. It's an audio question.
00:13:50 --> 00:13:52 Speaker C: Hi Space Nuts, it's Doug and Hazel the
00:13:52 --> 00:13:55 Wonderdoodle calling again. Thank you for
00:13:55 --> 00:13:57 your responses to my previous questions.
00:13:58 --> 00:14:00 My question this time is about
00:14:00 --> 00:14:03 uh, blocking sunlight. Given that
00:14:03 --> 00:14:06 we as humanity have no ability to
00:14:06 --> 00:14:08 control our carbon emissions, it seems.
00:14:09 --> 00:14:12 Um, the next question is to me,
00:14:12 --> 00:14:14 uh, is geoengineering possible?
00:14:15 --> 00:14:18 Now, given that, uh, seed
00:14:18 --> 00:14:20 in the higher atmosphere with reflective
00:14:20 --> 00:14:23 particles would probably not go over too well
00:14:23 --> 00:14:25 with the, uh, chemtrails people.
00:14:26 --> 00:14:29 I'm going to suggest that, uh, putting
00:14:29 --> 00:14:32 some sort of sun blocker out at Lagrange
00:14:32 --> 00:14:35 point one, uh, would be
00:14:35 --> 00:14:38 a solution that would probably need to be
00:14:38 --> 00:14:40 investigated. Um, ChatGPT
00:14:40 --> 00:14:43 suggested that a 3 million square
00:14:43 --> 00:14:46 meter parasol, for lack of a better word,
00:14:46 --> 00:14:49 would block 1% of the sun's light
00:14:49 --> 00:14:51 hitting the Earth. Don't, um, know what the
00:14:51 --> 00:14:53 magic number is. Don't know if we should even
00:14:53 --> 00:14:56 do this. But the question I have is
00:14:56 --> 00:14:59 does anybody know about anybody working on
00:14:59 --> 00:15:02 this particular program right now
00:15:02 --> 00:15:05 as uh, a contingency? Thanks very much.
00:15:06 --> 00:15:06 Have a good day.
00:15:07 --> 00:15:09 Andrew Dunkley: You too, Doug. Thank you. And hello to Hazel
00:15:09 --> 00:15:12 the Wonder Doodle. Uh, this has come
00:15:12 --> 00:15:14 up before and I do think somebody has been
00:15:14 --> 00:15:17 looking into the possibility of putting a
00:15:17 --> 00:15:19 parasol in space to try and uh,
00:15:19 --> 00:15:22 shade Earth. Um, I
00:15:22 --> 00:15:24 just don't know how well it would work.
00:15:25 --> 00:15:28 Jonti Horner: It's a challenge. I mean it, it, the reason
00:15:28 --> 00:15:29 I'm chuckling a little bit in the background
00:15:29 --> 00:15:31 here is not actually about this idea, which I
00:15:31 --> 00:15:33 think is a good one. It's hazel the wind area
00:15:33 --> 00:15:34 as well, isn't it?
00:15:34 --> 00:15:35 Andrew Dunkley: That's what's making you chuckle.
00:15:35 --> 00:15:37 Jonti Horner: It's not even Hazel the Wonder Doodle. It
00:15:37 --> 00:15:39 just amuses me that on the one hand we're
00:15:39 --> 00:15:41 talking here about building parasols to
00:15:41 --> 00:15:43 shield the sun from the daytime sky, while at
00:15:43 --> 00:15:45 the same time a few weeks ago we talked about
00:15:45 --> 00:15:47 a group of idiots with a startup in
00:15:47 --> 00:15:49 California to reflect the sun to shine it on
00:15:49 --> 00:15:51 the night times. And I've got visions of
00:15:51 --> 00:15:53 the fact that you get these wonderful geo
00:15:53 --> 00:15:56 engineers deliberately shielding blocking
00:15:56 --> 00:15:58 sunlight from the daylight sky only to have
00:15:58 --> 00:15:59 their work undone by a group of equally
00:15:59 --> 00:16:02 stupid people shining, um, lights on the
00:16:02 --> 00:16:04 nighttime sky to just basically make the
00:16:04 --> 00:16:06 nights hotter and offset all of the good
00:16:06 --> 00:16:08 work. Um, but that's more me chuckling at the
00:16:08 --> 00:16:10 idiocy of reflector orbital than it is about
00:16:10 --> 00:16:12 this question. Because this is actually a
00:16:12 --> 00:16:14 really good question, Doug. It is
00:16:14 --> 00:16:17 abundantly clear, um, that.
00:16:17 --> 00:16:19 Okay, don't mind me. I just got a weird pop
00:16:19 --> 00:16:21 up saying I'm going to expire
00:16:22 --> 00:16:24 after 150 minutes of inactivity, which is
00:16:24 --> 00:16:25 never good. But I don't think that's to do
00:16:25 --> 00:16:27 with space nuts. So I've just moved my mouse
00:16:27 --> 00:16:30 and all is good. So I am not going wake spire
00:16:30 --> 00:16:32 live on air. This is good. Yeah.
00:16:32 --> 00:16:35 So there is fundamentally an issue that the
00:16:35 --> 00:16:37 planet is warming and the planet is warming
00:16:37 --> 00:16:40 because of human activities. And that is
00:16:41 --> 00:16:43 not open, uh, for dispute really anymore. I
00:16:43 --> 00:16:44 know that there are a variety of opinions
00:16:44 --> 00:16:46 available on this, but for me as an
00:16:46 --> 00:16:48 astronomer, the evidence is utterly
00:16:48 --> 00:16:51 overwhelming. And the only thing that can
00:16:51 --> 00:16:53 explain the changes that we're seeing, not
00:16:53 --> 00:16:55 the size of the changes, but the speed of the
00:16:55 --> 00:16:57 changes, is human activity. No
00:16:57 --> 00:17:00 physical process, other than perhaps a
00:17:00 --> 00:17:03 rock hitting the Earth and killing everybody,
00:17:03 --> 00:17:05 um, like the dinosaur level extinction, there
00:17:05 --> 00:17:07 is nothing else that could cause this rate of
00:17:07 --> 00:17:10 change. So it's very, very clear that human
00:17:10 --> 00:17:13 activity is the cause of this and, um, that
00:17:13 --> 00:17:14 there is some inertia in trying to persuade
00:17:14 --> 00:17:16 humans to stop doing the things that cause
00:17:16 --> 00:17:18 the problems and understand that. So there's
00:17:18 --> 00:17:21 a growing list of suggestions of ways that we
00:17:21 --> 00:17:23 could mitigate for climate change out there.
00:17:24 --> 00:17:26 One, as Doug said, is sprinkling reflective
00:17:26 --> 00:17:28 particles into the upper atmosphere to
00:17:28 --> 00:17:31 effectively increase the Earth's albedo, uh,
00:17:31 --> 00:17:33 which would mean more energy was reflected to
00:17:33 --> 00:17:35 space and less makes it down to the surface
00:17:35 --> 00:17:37 of the Earth to kind of heat the pressure
00:17:37 --> 00:17:40 cooker. And that could
00:17:40 --> 00:17:42 possibly work. It'll be interesting to see
00:17:42 --> 00:17:44 what role SpaceX plays in that in the years
00:17:44 --> 00:17:47 to come, because with all of the satellites
00:17:47 --> 00:17:50 they're launching, there's a growing, um,
00:17:50 --> 00:17:51 number of things returning to Earth and
00:17:51 --> 00:17:53 burning up in the upper atmosphere that are
00:17:53 --> 00:17:56 depositing metals like aluminum into the
00:17:56 --> 00:17:58 upper atmosphere. And nobody's really sure
00:17:58 --> 00:18:00 what's going to happen there. So that might
00:18:00 --> 00:18:02 actually inadvertently do exactly what Doug
00:18:02 --> 00:18:05 mentioned and increase the Earth's albedo
00:18:05 --> 00:18:08 and offset some climate change, or it might
00:18:08 --> 00:18:09 make it worse. People are still trying to
00:18:09 --> 00:18:11 figure out what's going to happen there. And
00:18:11 --> 00:18:13 that ties into the idea that space is still a
00:18:13 --> 00:18:16 little bit of the wild, Wild west, in that
00:18:16 --> 00:18:19 things are happening faster than legislation
00:18:19 --> 00:18:21 can adapt. You know, we've got tons of
00:18:21 --> 00:18:23 aluminium being added to the atmosphere and
00:18:23 --> 00:18:25 we don't know what it's going to do, but that
00:18:25 --> 00:18:27 might have part of this effect. But an
00:18:27 --> 00:18:30 obvious way that you could cool the Earth is
00:18:30 --> 00:18:33 by blocking some sunlight. Fundamentally,
00:18:33 --> 00:18:35 that makes sense. If you block 1% of the
00:18:35 --> 00:18:37 sun's light, you block 1% of the energy
00:18:37 --> 00:18:39 coming into the Earth, which will be about
00:18:39 --> 00:18:41 13.6 watts. The solar constant's about
00:18:41 --> 00:18:44 1360 watts per square meter. Block, uh,
00:18:44 --> 00:18:47 1% of that, that will be 13.6 watts,
00:18:47 --> 00:18:49 and that will be more than enough to offset
00:18:49 --> 00:18:52 climate change and probably more so. But
00:18:52 --> 00:18:54 let's say we wanted to block 1% of the light
00:18:54 --> 00:18:56 from the sun. That means you would need a
00:18:56 --> 00:18:59 parasol that is equal to 1% of the
00:18:59 --> 00:19:01 cross section of the Earth, Uh, if that
00:19:01 --> 00:19:03 parasol blocked all of the light from the sun
00:19:03 --> 00:19:05 that was hitting it. So that means
00:19:06 --> 00:19:08 1% of the Earth's surface would be dark. The
00:19:08 --> 00:19:11 sun wouldn't be falling on it. Or you diffuse
00:19:11 --> 00:19:14 that, and, um, you have 1% less light coming
00:19:14 --> 00:19:16 down. So if you do the maths of that. The
00:19:16 --> 00:19:19 Earth has a radius
00:19:19 --> 00:19:22 of about 6
00:19:22 --> 00:19:24 kilometers. That varies because the Earth's a
00:19:24 --> 00:19:26 bit ablate. So the radius from pole to pole
00:19:27 --> 00:19:29 is different to the radius across the
00:19:29 --> 00:19:31 equator. But we can use that as a mean
00:19:31 --> 00:19:34 radius. That means that the Earth, uh, has a
00:19:34 --> 00:19:37 surface area of about 10, 1.9,
00:19:37 --> 00:19:39 I think it was, times 10 to the 14
00:19:40 --> 00:19:43 meters squared. So to
00:19:43 --> 00:19:46 block 1% of the light, you'd need a
00:19:46 --> 00:19:49 parasol. That is 1% of that. So that would be
00:19:49 --> 00:19:51 about 1, um, point 28 times 10 to
00:19:51 --> 00:19:54 the 12 meters squared. Which means
00:19:54 --> 00:19:57 that you will need a parasol. I'm sorry,
00:19:57 --> 00:19:58 kilometers squared. I've done this
00:19:58 --> 00:20:01 calculation in kilometers, um, which would.
00:20:01 --> 00:20:03 No, that is in meters, sorry. Which would
00:20:03 --> 00:20:06 mean you'd need a parasol if you made it
00:20:06 --> 00:20:08 Square. That is
00:20:08 --> 00:20:10 1130 kilometers on a
00:20:10 --> 00:20:11 side
00:20:13 --> 00:20:16 that I think is technologically beyond us at
00:20:16 --> 00:20:19 the minute. Um, added to which,
00:20:19 --> 00:20:21 you know that the politicians would want us
00:20:21 --> 00:20:23 to mine that material on Earth and launch it
00:20:23 --> 00:20:25 because that would be more profitable. So the
00:20:25 --> 00:20:26 process of mining and launching all that
00:20:26 --> 00:20:29 material to build 1 kilometers on each
00:20:29 --> 00:20:32 side. Parasol Will probably put far more
00:20:32 --> 00:20:34 greenhouse gases into the atmosphere and
00:20:34 --> 00:20:36 exacerbate the problem. The other challenge
00:20:36 --> 00:20:38 you'd have with the parasol issue, though, is
00:20:38 --> 00:20:40 that the L1 point, which would be the obvious
00:20:40 --> 00:20:43 place to put it, that's a point between the
00:20:43 --> 00:20:45 Earth and the Sun. Where an object would
00:20:45 --> 00:20:47 rotate at the same orbital period as the
00:20:47 --> 00:20:49 Earth. And, um, be in this kind of semi
00:20:49 --> 00:20:51 stable location. That's where a lot of our
00:20:51 --> 00:20:53 solar observation spacecraft go, like soho,
00:20:53 --> 00:20:55 to give us early warning of space weather.
00:20:56 --> 00:20:59 Now, the L1 point is about 1.5 million
00:20:59 --> 00:21:01 kilometers away. Things at
00:21:01 --> 00:21:04 L1 are not fully stable. So they need rockets
00:21:04 --> 00:21:05 and actuators to keep them on point. Because
00:21:05 --> 00:21:08 if they drift too far away, they'll fall out
00:21:08 --> 00:21:10 of the stable area and go off orbiting the
00:21:10 --> 00:21:13 sun on the rock. So what you need to do is
00:21:13 --> 00:21:16 have an object 1 kilometers on each
00:21:16 --> 00:21:18 side. Located one and a half million
00:21:18 --> 00:21:21 kilometers away. That could be positioned
00:21:21 --> 00:21:23 accurately enough that the shadow it casts
00:21:23 --> 00:21:26 hits a target 6 km
00:21:26 --> 00:21:29 in radius rather than missing us. So as it
00:21:29 --> 00:21:31 drifts around, we'd have to keep it on point
00:21:31 --> 00:21:33 to an accuracy of just a few hundred
00:21:33 --> 00:21:36 kilometers. And so this is one of those
00:21:36 --> 00:21:38 things where it's a fabulous idea for science
00:21:38 --> 00:21:40 fiction and it is the kind of thing where we
00:21:40 --> 00:21:42 can imagine all of the steps we need to take
00:21:42 --> 00:21:44 to make it work. So it's within the bounds of
00:21:44 --> 00:21:47 our technology in terms of our ability to
00:21:47 --> 00:21:50 make stuff, but it's the scale of it that
00:21:50 --> 00:21:53 makes it impractical. And that's why a
00:21:53 --> 00:21:56 lot of these ideas of parasols
00:21:56 --> 00:21:59 fall down, is that the amount of area
00:21:59 --> 00:22:01 you'd have to cover to block enough light to
00:22:01 --> 00:22:03 make it feasible are so huge that it's just
00:22:03 --> 00:22:06 technologically the building of them and the
00:22:06 --> 00:22:08 keeping them on point will be too much of a
00:22:08 --> 00:22:10 challenge. It be a global endeavor that would
00:22:10 --> 00:22:13 make the efforts for the Apollo missions seem
00:22:13 --> 00:22:16 like tiny little small fry in comparison.
00:22:16 --> 00:22:18 I don't know if anybody's ever done a
00:22:18 --> 00:22:21 calculation of the cost that this would have.
00:22:22 --> 00:22:23 Um, but I suspect there are other
00:22:23 --> 00:22:26 geoengineering ideas that will be more
00:22:26 --> 00:22:28 financially feasible. Uh,
00:22:29 --> 00:22:31 I'm always an optimist. I mean, I am very
00:22:31 --> 00:22:32 worried, like everybody is, about climate
00:22:32 --> 00:22:35 change. I have been since I was a kid. I've
00:22:35 --> 00:22:38 lived in places where it is writ large on
00:22:38 --> 00:22:39 the landscape. I always talk about when I
00:22:39 --> 00:22:41 lived in Switzerland, and they've got
00:22:41 --> 00:22:43 photographs from mid summer, uh, in all these
00:22:43 --> 00:22:45 little Alpine villages of the glacier just
00:22:45 --> 00:22:47 behind the village. Evening, midsummer. And
00:22:47 --> 00:22:49 then you step outside and you can't see the
00:22:49 --> 00:22:51 glacier because it's retreated so far up the
00:22:51 --> 00:22:53 mountains it's no longer in view. So I've
00:22:53 --> 00:22:56 lived in places where it's obvious. But I'm
00:22:56 --> 00:22:58 always of the idea that eventually human
00:22:58 --> 00:23:01 ingenuity and commercial, um,
00:23:01 --> 00:23:03 interests will get to the point where it is
00:23:04 --> 00:23:06 something we'll solve. And I think we're
00:23:06 --> 00:23:07 seeing that a bit now with electric cars.
00:23:07 --> 00:23:10 We've had the technology to have electric
00:23:10 --> 00:23:12 vehicles for more than 100 years. I remember
00:23:12 --> 00:23:14 getting milk delivered by the milkman as a
00:23:14 --> 00:23:16 kid. And, uh, they were going around in
00:23:16 --> 00:23:18 electric milk carts, you know, so we have
00:23:18 --> 00:23:21 that technology even then. But for a long
00:23:21 --> 00:23:22 time nobody's had electric cars, nobody's
00:23:22 --> 00:23:25 considered it solvable. But eventually the
00:23:25 --> 00:23:26 costs have dropped enough that they're a
00:23:26 --> 00:23:28 viable alternative and now people are taking
00:23:28 --> 00:23:30 them up. So you're seeing a drop in the
00:23:30 --> 00:23:32 number of petrol vehicles. And I'd like to
00:23:32 --> 00:23:35 think that because a lot of the things that
00:23:35 --> 00:23:37 we do to cause climate change are
00:23:37 --> 00:23:39 fundamentally inefficient, as our technology
00:23:39 --> 00:23:42 improves, we'll move to much more
00:23:42 --> 00:23:44 efficient processes that generate less of the
00:23:44 --> 00:23:46 things that cause climate change. And, uh, we
00:23:46 --> 00:23:48 will find a solution. But the problem is the
00:23:48 --> 00:23:50 lag time is such that the longer we wait, the
00:23:50 --> 00:23:52 worse it's going to get before it gets better
00:23:52 --> 00:23:54 again. And there are some suggestions that,
00:23:54 --> 00:23:57 for example, the horrendous hurricane that
00:23:57 --> 00:24:00 hit Jamaica last week was significantly
00:24:00 --> 00:24:02 worse because of the effect of climate change
00:24:02 --> 00:24:03 on the temperatures of the water. There's now
00:24:03 --> 00:24:06 actually a whole branch of mathematical
00:24:06 --> 00:24:08 science that delves into
00:24:09 --> 00:24:12 calculating not a yes, no did climate change
00:24:12 --> 00:24:15 cause this event, but rather a statistical
00:24:15 --> 00:24:18 analysis of how much worse was this
00:24:18 --> 00:24:20 event as a result of the effects of climate
00:24:20 --> 00:24:22 change. And I think the numbers for that
00:24:22 --> 00:24:25 hurricane last week were quite startling
00:24:25 --> 00:24:28 that it was made noticeably worse because of
00:24:28 --> 00:24:30 the increased heating of the ocean and all
00:24:30 --> 00:24:32 the rest of it. Yeah, it is a real problem
00:24:32 --> 00:24:34 with. We want to get solutions, but I think
00:24:34 --> 00:24:35 the parasol is a bit too hard.
00:24:36 --> 00:24:38 Andrew Dunkley: Yeah, I did read the science behind why that
00:24:38 --> 00:24:40 storm was so severe and it was quite an
00:24:40 --> 00:24:42 interesting read. And I won't go into it now
00:24:42 --> 00:24:44 because I probably get half of it wrong.
00:24:44 --> 00:24:47 But, um, you might also be interested,
00:24:47 --> 00:24:49 Doug, to know that there have been some
00:24:49 --> 00:24:52 researchers looking into this. Not just
00:24:53 --> 00:24:56 maybe a single object in space to,
00:24:56 --> 00:24:59 to block the sun. But University, uh, of
00:24:59 --> 00:25:01 Arizona was looking at a, uh, cloud of small
00:25:02 --> 00:25:04 spacecraft. Uh, there was another research,
00:25:05 --> 00:25:08 uh, effort at mit, uh,
00:25:08 --> 00:25:10 looking at inflatable space bubbles. Uh,
00:25:10 --> 00:25:13 another idea out of the University of Hawaii,
00:25:13 --> 00:25:16 um, tethering shades to an asteroid. The
00:25:16 --> 00:25:18 asteroid being used as a counterweight if
00:25:18 --> 00:25:19 they could capture one. That's another
00:25:20 --> 00:25:22 impossible dream at the moment. Solar sails
00:25:22 --> 00:25:24 and lightweight films and, and even one,
00:25:25 --> 00:25:27 uh, proposed only a couple of years ago was,
00:25:27 --> 00:25:30 um, to start ejecting lunar
00:25:30 --> 00:25:33 dust into space to create
00:25:33 --> 00:25:36 a dust cloud to block the sun. M.
00:25:36 --> 00:25:39 My worry is if we do decide
00:25:39 --> 00:25:41 that that's the solution and we do it and
00:25:41 --> 00:25:44 then we solve the problem of global warming,
00:25:45 --> 00:25:47 won't we then put ourselves in a position
00:25:47 --> 00:25:50 where we could cause, uh, a global
00:25:50 --> 00:25:50 winter?
00:25:51 --> 00:25:51 Jonti Horner: Um.
00:25:54 --> 00:25:56 Andrew Dunkley: Even if we reach a point where we've got the
00:25:56 --> 00:25:59 technology to solve the problem, as
00:25:59 --> 00:26:01 Doug said, should we do it?
00:26:01 --> 00:26:04 Jonti Horner: And we also come to
00:26:04 --> 00:26:06 really interesting questions because
00:26:07 --> 00:26:10 underlying the climate change we've got, um,
00:26:10 --> 00:26:12 there's also the fact that the Earth's, uh,
00:26:12 --> 00:26:14 climate changes naturally on much longer
00:26:14 --> 00:26:15 timescales. We get the glacial and
00:26:15 --> 00:26:18 interglacial periods. So if we ever do get to
00:26:18 --> 00:26:20 the point where we've got climate control,
00:26:20 --> 00:26:23 so. So in other words, we can set the Earth's
00:26:23 --> 00:26:25 climate to be. At a certain point we can fix
00:26:25 --> 00:26:27 a problem. And if we can fix a problem, we
00:26:27 --> 00:26:29 can then say where we want the climate to
00:26:29 --> 00:26:31 sit. What do we choose? Do we allow
00:26:32 --> 00:26:34 that very slow pace of climate change to
00:26:34 --> 00:26:36 happen? Do we figure out the conditions that
00:26:36 --> 00:26:39 are optimal and set it there? There's
00:26:39 --> 00:26:41 a lot of really interesting stuff that would
00:26:41 --> 00:26:42 feed into science fiction rather than science
00:26:42 --> 00:26:44 fact that come from the fact that if you've
00:26:44 --> 00:26:45 got to the point where you can solve the
00:26:45 --> 00:26:47 problem, you've got to the point where you
00:26:47 --> 00:26:50 can geoengineer the Earth's climate to suit.
00:26:50 --> 00:26:52 So where do you therefore set the sweet spot?
00:26:52 --> 00:26:55 Do you set it at uh, the year 2000 mean, the
00:26:55 --> 00:26:58 1900 mean? Do you make it a little bit
00:26:58 --> 00:26:59 cooler than that? Do you make it a little bit
00:26:59 --> 00:27:01 warmer than that? It's a really interesting
00:27:01 --> 00:27:04 one. Which for an incredibly complex and
00:27:04 --> 00:27:06 chaotic system, um, would lead to a lot of
00:27:06 --> 00:27:09 implications about weather disasters and all
00:27:09 --> 00:27:11 the rest of it. Yeah, there's a lot of
00:27:11 --> 00:27:12 interesting stuff there. I think it's going
00:27:12 --> 00:27:14 to be interesting times for the next hundred
00:27:14 --> 00:27:16 or two hundred years as humanity tries to
00:27:16 --> 00:27:17 solve the problems it's made.
00:27:18 --> 00:27:21 Andrew Dunkley: Indeed. Yes. Thank you Doug, Great to hear
00:27:21 --> 00:27:23 from you. Keep them coming. There's some
00:27:23 --> 00:27:25 terrific ideas out there that uh, people want
00:27:25 --> 00:27:28 to learn more about. And this is
00:27:28 --> 00:27:31 Space Nuts with Andrew Dunkley and Jonti
00:27:31 --> 00:27:32 Horner.
00:27:36 --> 00:27:37 Space Nuts.
00:27:37 --> 00:27:40 Our next question, uh, comes from another
00:27:40 --> 00:27:42 YouTuber. Uh, and
00:27:42 --> 00:27:45 uh, the question is who has the salvage
00:27:45 --> 00:27:48 rights on all the scrap satellites and is
00:27:48 --> 00:27:51 there a plan or a uh, map of all the
00:27:51 --> 00:27:54 defunct scrap in orbit? Possibly in the
00:27:54 --> 00:27:56 future there would be good business in
00:27:56 --> 00:27:58 recovering all the precious metals, et
00:27:58 --> 00:28:00 cetera. It's a good question. I know they
00:28:00 --> 00:28:02 were experimenting with different ways of
00:28:02 --> 00:28:05 bringing down defunct satellites, uh,
00:28:06 --> 00:28:08 and all they were doing was like testing
00:28:08 --> 00:28:11 harpoons and things like that or whatever to
00:28:11 --> 00:28:14 make them re enter and burn up. But this is,
00:28:14 --> 00:28:17 this is um, a whole new ball game. Salvage.
00:28:17 --> 00:28:19 Uh, I don't, I haven't heard of it.
00:28:19 --> 00:28:22 Jonti Horner: Have you? It's yet
00:28:22 --> 00:28:25 another area where legislation is not keeping
00:28:25 --> 00:28:28 up with use. So there's a
00:28:28 --> 00:28:30 lot of challenges with this. Space is vastly
00:28:30 --> 00:28:32 big and um, the things we put up there are
00:28:32 --> 00:28:34 very small compared to the size of the space
00:28:34 --> 00:28:37 that's up there. There are a lot of efforts
00:28:37 --> 00:28:39 going on to map and to keep track of all of
00:28:39 --> 00:28:42 the bits of debris, both large scale like
00:28:42 --> 00:28:44 satellites and former rocket bodies, down to
00:28:44 --> 00:28:46 the very small fragments you've got out
00:28:46 --> 00:28:48 there. And that's the whole Area of space,
00:28:48 --> 00:28:50 situational awareness. There's telescopes
00:28:50 --> 00:28:52 around the world tracking debris, keeping it
00:28:52 --> 00:28:55 in databases. And the thing there is
00:28:55 --> 00:28:57 that you can't just assume that once you've
00:28:57 --> 00:28:58 seen it, you know what it's orbit is and
00:28:58 --> 00:29:00 you'll know where it is forevermore, because
00:29:00 --> 00:29:02 it's a complex environment where the Earth's
00:29:02 --> 00:29:04 atmosphere is breathing in and out, getting
00:29:04 --> 00:29:06 bigger and smaller, and the solar wind is
00:29:06 --> 00:29:08 varying. And all these things that happen,
00:29:08 --> 00:29:11 even down to the subtleties of the varying
00:29:11 --> 00:29:13 densities of different parts of the Earth's
00:29:13 --> 00:29:15 surface, causing slight changes in the
00:29:15 --> 00:29:17 Earth's gravity at, uh, the kind of level you
00:29:17 --> 00:29:19 want to track these things, all of that means
00:29:19 --> 00:29:21 that you need to keep tracking them. You
00:29:21 --> 00:29:22 can't just find them once and say it's there
00:29:22 --> 00:29:25 and that's it. So there's a whole burgeoning
00:29:25 --> 00:29:26 kind of research industry built around
00:29:27 --> 00:29:29 tracking this debris, using laser range
00:29:29 --> 00:29:31 finding to get as accurate a position as
00:29:31 --> 00:29:34 possible. And part of the reason for that is
00:29:34 --> 00:29:36 so that things like expensive satellites and
00:29:36 --> 00:29:38 the space station can dodge when there's a
00:29:38 --> 00:29:40 chance of an impact. That's always helpful.
00:29:41 --> 00:29:43 Um, it is also just so that we were aware of
00:29:43 --> 00:29:44 what's up there, and it's a problem that's
00:29:44 --> 00:29:46 only going to get worse. Now, I did a little
00:29:46 --> 00:29:49 bit of searching around because I had never
00:29:49 --> 00:29:52 thought of the salvage of
00:29:52 --> 00:29:55 satellites and stuff like that as being a
00:29:55 --> 00:29:58 thing. Now, in maritime
00:29:58 --> 00:30:00 law, there's this concept of the right to
00:30:00 --> 00:30:02 salvage, which is when something is becoming
00:30:02 --> 00:30:05 dangerous or when it's out, which allows
00:30:05 --> 00:30:07 people to claim salvage rights. There is no
00:30:07 --> 00:30:09 such thing in space. I found a few articles
00:30:09 --> 00:30:12 that all confirm that. And I quote from an
00:30:12 --> 00:30:15 article in the spacereview.com, there is no
00:30:15 --> 00:30:17 right of salvage analogous to the right found
00:30:17 --> 00:30:19 in maritime law. Which means that even though
00:30:19 --> 00:30:21 a satellite or some other space object may
00:30:21 --> 00:30:24 not be functioning, that does not imply that
00:30:24 --> 00:30:26 it has been abandoned by the nation that
00:30:26 --> 00:30:29 launched it. And there's a pretty lengthy
00:30:29 --> 00:30:31 spiel following that which basically says, if
00:30:31 --> 00:30:32 you don't have concept for the nation that
00:30:32 --> 00:30:35 launched and operated that thing, you're not
00:30:35 --> 00:30:37 allowed to dispose of it or interfere with
00:30:37 --> 00:30:37 it.
00:30:38 --> 00:30:41 Andrew Dunkley: In fact, uh, I might just add a caveat to
00:30:41 --> 00:30:43 that. Uh, if you launch something into space,
00:30:43 --> 00:30:45 it is your responsibility.
00:30:45 --> 00:30:48 Jonti Horner: Yes, absolutely. Which follows on to the
00:30:48 --> 00:30:50 next point. That's the issue about salvaging
00:30:50 --> 00:30:53 it while it is still in space. And, um, I
00:30:53 --> 00:30:55 could imagine that with sufficiently future
00:30:56 --> 00:30:58 technology and a more crowded environment
00:30:58 --> 00:31:00 around space, there could be a commercial
00:31:00 --> 00:31:02 opportunity for somebody to develop Yeah, a
00:31:02 --> 00:31:05 cleanup crew, which companies
00:31:05 --> 00:31:08 who own a satellite can pay to
00:31:08 --> 00:31:09 recover their satellite and dispose of it
00:31:09 --> 00:31:12 safely or to give harvesting rights or
00:31:12 --> 00:31:14 whatever, where that's dealt with. I could
00:31:14 --> 00:31:16 see that as a commercial thing down the line.
00:31:16 --> 00:31:18 But it also has an impact on what happens
00:31:18 --> 00:31:21 when satellites fall back to Earth. Should
00:31:21 --> 00:31:23 they make it through the Earth's atmosphere
00:31:23 --> 00:31:25 intact and make it to the surface of the
00:31:25 --> 00:31:27 Earth, as we saw with Skylab In Australia in
00:31:27 --> 00:31:30 1973, for example, um, and more
00:31:30 --> 00:31:33 recently with fragments of SpaceX debris
00:31:33 --> 00:31:36 littering the planet, you might think that if
00:31:36 --> 00:31:38 it falls in your backyard, it's yours, but it
00:31:38 --> 00:31:41 isn't. The ownership remains with the people
00:31:41 --> 00:31:44 or the country that launched it. And so
00:31:44 --> 00:31:47 back when Skylab, um, landed in Western
00:31:47 --> 00:31:49 Australia, the area in Western Australia
00:31:49 --> 00:31:52 where it landed cheekily sent NASA a
00:31:52 --> 00:31:55 littering notice for a fine, which got paid,
00:31:55 --> 00:31:57 um, which was quite good fun a few years ago
00:31:57 --> 00:32:00 when large pieces of SpaceX rocket landed in
00:32:00 --> 00:32:01 the Snowy Mountains in Australia.
00:32:02 --> 00:32:02 Andrew Dunkley: Yes.
00:32:02 --> 00:32:04 Jonti Horner: People were advised not to pick the bits up
00:32:04 --> 00:32:06 and collect them to let the Australian Space
00:32:06 --> 00:32:09 Agency know, because technically,
00:32:09 --> 00:32:11 the space agency has a whole plan. And this
00:32:11 --> 00:32:13 is laid out on the space agency website under
00:32:13 --> 00:32:15 space.govau
00:32:16 --> 00:32:18 discovery of space
00:32:18 --> 00:32:21 debris in Australia. So
00:32:21 --> 00:32:24 space.govau discovery of space
00:32:24 --> 00:32:26 debris in Australia details
00:32:26 --> 00:32:29 the regulatory side of things and what the
00:32:29 --> 00:32:32 space agency does, and says the Australian
00:32:32 --> 00:32:33 government has plans in place for events
00:32:33 --> 00:32:35 where space debris impacts Australia.
00:32:36 --> 00:32:37 Description of what it is and what the role
00:32:37 --> 00:32:39 is, and it lays out the steps that if you
00:32:39 --> 00:32:41 find space debris in your backyard, you
00:32:41 --> 00:32:44 should follow. Step one is do not touch it.
00:32:44 --> 00:32:46 And I cannot stress this enough, do not touch
00:32:46 --> 00:32:48 it. Space objects are built from materials
00:32:48 --> 00:32:51 that can be hazardous. This is exacerbated by
00:32:51 --> 00:32:52 coming back through the atmosphere and
00:32:52 --> 00:32:55 getting damaged. So it says space debris
00:32:55 --> 00:32:56 should only be handled by appropriately
00:32:56 --> 00:32:59 trained and equipped professionals. That was
00:32:59 --> 00:33:01 particularly relevant with the fragments of
00:33:01 --> 00:33:03 the SpaceX rocket that fell near the Turks
00:33:03 --> 00:33:05 and Caicos Islands earlier this year, because
00:33:05 --> 00:33:07 there was a whole brouhaha about the cleanup
00:33:07 --> 00:33:10 and SpaceX was not following its requirements
00:33:10 --> 00:33:12 and not doing much, and people were upset and
00:33:12 --> 00:33:14 some people had been going and collecting
00:33:14 --> 00:33:15 bits of debris and there was a risk they'd
00:33:15 --> 00:33:18 fall ill and stuff like this. So, step one,
00:33:18 --> 00:33:20 don't touch it. Step two, contact your local
00:33:20 --> 00:33:23 authorities. So, um, if the situation is
00:33:23 --> 00:33:25 urgent, contact triple zero. So I guess
00:33:25 --> 00:33:27 that's if a piece of a SpaceX satellite hits
00:33:27 --> 00:33:30 your Tesla, don't contact the museum, call
00:33:30 --> 00:33:32 the police. Fair enough. Otherwise, call the
00:33:32 --> 00:33:34 police assistant line. So you get some advice
00:33:35 --> 00:33:37 and Then you notify the space agency. And
00:33:37 --> 00:33:40 what the space agency then has to do is
00:33:40 --> 00:33:43 figure out whose bit of debris it is, get in
00:33:43 --> 00:33:45 touch with them, um, and liaise with them
00:33:45 --> 00:33:47 because there is a requirement for us to
00:33:47 --> 00:33:50 return the material to them. It is their
00:33:50 --> 00:33:52 property. And um, so from
00:33:52 --> 00:33:55 salvaging here on Earth you don't have those
00:33:55 --> 00:33:57 salvage laws because even if it's a burnt up
00:33:57 --> 00:33:59 fragment of rocket, it's still property of
00:33:59 --> 00:34:01 SpaceX or it's still property of the Chinese
00:34:01 --> 00:34:04 government. And so we don't have that kind of
00:34:04 --> 00:34:06 salvage set up at the minute. There's a
00:34:06 --> 00:34:08 description of what happens once debris is
00:34:08 --> 00:34:10 identified as space debris. And it says if an
00:34:10 --> 00:34:12 item is confirmed as space debris, the
00:34:12 --> 00:34:14 Australian government has international
00:34:14 --> 00:34:16 obligations to notify the launching authority
00:34:16 --> 00:34:19 of the discovery and upon request may be
00:34:19 --> 00:34:22 required to return the debris. So you
00:34:22 --> 00:34:24 can't salvage it. Now this
00:34:25 --> 00:34:28 may become something where the laws evolve in
00:34:28 --> 00:34:30 the years to come. As I say all the time our
00:34:30 --> 00:34:32 uh, user space is still in this Wild west
00:34:32 --> 00:34:35 phase where our ability to do stuff is
00:34:35 --> 00:34:37 growing much more rapidly than our ability to
00:34:37 --> 00:34:39 legislate for it. Um, and there's a lot of
00:34:39 --> 00:34:41 commercial interest in not advancing the
00:34:41 --> 00:34:44 legislation because if you advance the
00:34:44 --> 00:34:46 legislation you put more costs on the
00:34:46 --> 00:34:47 commercial entities. So they have a vested
00:34:47 --> 00:34:50 interest in not having legislation about
00:34:50 --> 00:34:52 launches, not legislating for the number you
00:34:52 --> 00:34:54 can make or the environmental requirements.
00:34:55 --> 00:34:57 And countries are leery of doing it because
00:34:57 --> 00:34:59 you can launch the space from all over the
00:34:59 --> 00:35:01 globe. So if you say to uh, SpaceX,
00:35:02 --> 00:35:04 you need to meet all these punishing
00:35:04 --> 00:35:06 environmental conditions before you launch
00:35:06 --> 00:35:07 and you've got to do all this with your
00:35:07 --> 00:35:10 satellites, SpaceX can easily say, well
00:35:10 --> 00:35:11 that's fine, we'll take our investment and
00:35:11 --> 00:35:14 move it to another country. So there's a lot
00:35:14 --> 00:35:16 of challenges there. But I could imagine in
00:35:16 --> 00:35:18 decades to come, as commercial space becomes
00:35:18 --> 00:35:20 more established and our use of space becomes
00:35:20 --> 00:35:23 much more varied and much more numerous,
00:35:23 --> 00:35:25 a astronomers will complain because you get
00:35:25 --> 00:35:27 more and more spoiling of the night sky, but
00:35:27 --> 00:35:29 you'll also get the opportunity for
00:35:29 --> 00:35:30 businesses, just like this question
00:35:30 --> 00:35:33 describes, to develop why there may be the
00:35:33 --> 00:35:35 commercial value for people to recover
00:35:35 --> 00:35:38 defunct satellites in orbit, capture them,
00:35:38 --> 00:35:40 maybe even lift them up to a higher orbit to
00:35:40 --> 00:35:43 a factory that can process the materials and
00:35:43 --> 00:35:44 let people then build new satellites in
00:35:44 --> 00:35:47 orbit. That way you lower the risk of them
00:35:47 --> 00:35:49 burning up in Earth's atmosphere, you get rid
00:35:49 --> 00:35:51 of the possibility of them altering the
00:35:51 --> 00:35:53 atmosphere to make climate change worse or
00:35:53 --> 00:35:55 better, as we discussed before. And um,
00:35:55 --> 00:35:57 you'll lower the cost of launching new ones
00:35:57 --> 00:35:59 if you could reprocess and salvage and
00:35:59 --> 00:36:01 rebuild. Yeah, it's probably not commercially
00:36:01 --> 00:36:03 feasible yet, which is why nobody's doing it
00:36:03 --> 00:36:06 yet. But it may well become so and so. This
00:36:06 --> 00:36:08 is something that I'd expect to evolve in the
00:36:08 --> 00:36:11 next say 50 years as all this stuff becomes
00:36:11 --> 00:36:11 more entrenched.
00:36:13 --> 00:36:15 Andrew Dunkley: It's interesting uh, in regard to the
00:36:15 --> 00:36:17 ownership side of things. Uh, it's like when
00:36:17 --> 00:36:19 you put your garbage bin out with all your
00:36:19 --> 00:36:22 stuff in it, it's still your stuff. And even
00:36:22 --> 00:36:25 as far as it being dumped in
00:36:25 --> 00:36:27 landfill, if you've thrown out your son's
00:36:27 --> 00:36:30 favorite toy and he wants it back, it's still
00:36:30 --> 00:36:33 his toy. So it's
00:36:33 --> 00:36:36 the same kind of thing, um, in a down to
00:36:36 --> 00:36:38 earth kind of way. And to our YouTube Music
00:36:38 --> 00:36:41 listener, um, just one final
00:36:41 --> 00:36:41 point.
00:36:41 --> 00:36:42 Jonti Horner: Yes.
00:36:42 --> 00:36:45 Andrew Dunkley: There are companies researching salvage in
00:36:45 --> 00:36:45 space.
00:36:46 --> 00:36:46 Jonti Horner: Newman.
00:36:46 --> 00:36:48 Andrew Dunkley: Ah space. Another one called AstroDailyPod
00:36:48 --> 00:36:51 Scale and of course the major parties, NASA
00:36:51 --> 00:36:54 and ESA and several others are
00:36:54 --> 00:36:56 looking into this. Uh but right now it's,
00:36:56 --> 00:36:59 it's not a very easy thing to do. But thanks
00:36:59 --> 00:37:01 for the question. Thanks for the question.
00:37:01 --> 00:37:01 Really good.
00:37:04 --> 00:37:06 Okay, we checked all four systems and being
00:37:06 --> 00:37:09 with a go space nats, uh, we have one
00:37:09 --> 00:37:12 final question. This one comes from Robert
00:37:12 --> 00:37:15 and Robert uh, is from the Netherlands
00:37:15 --> 00:37:17 uh, and he's got backing music on his
00:37:17 --> 00:37:18 question.
00:37:18 --> 00:37:21 Robert: Hello, this is Robert from Netherlands. I
00:37:21 --> 00:37:24 have a question for you today about radio
00:37:24 --> 00:37:27 waves because as we all know it's a very
00:37:27 --> 00:37:30 efficient low energy way of communicating
00:37:31 --> 00:37:34 data over vast distances. And
00:37:34 --> 00:37:36 I would think that if we are looking for
00:37:36 --> 00:37:38 aliens which I find very tantalizing at
00:37:38 --> 00:37:41 the subject, we should be looking for radio
00:37:41 --> 00:37:44 waves probably like 500
00:37:44 --> 00:37:47 light years of a radius of the earth which
00:37:48 --> 00:37:50 seems to be kind of a low priority. Never
00:37:50 --> 00:37:53 understood why, why there's there's a
00:37:53 --> 00:37:56 beanbags uh, observatory that can
00:37:56 --> 00:37:58 know really pinpoint these but you can't
00:37:58 --> 00:38:01 really cast a white net so to speak. Another
00:38:01 --> 00:38:04 square kilometer ray might be capable of
00:38:04 --> 00:38:07 this being built. Australia of course. I
00:38:07 --> 00:38:09 was hoping you guys would have some insights.
00:38:09 --> 00:38:12 They're going to be interact radio waves.
00:38:12 --> 00:38:14 Thank you so much time.
00:38:14 --> 00:38:17 Andrew Dunkley: Um, thank you Robert. Lovely
00:38:17 --> 00:38:20 music. Yeah, very, very spacey
00:38:20 --> 00:38:23 indeed. Um, I would have thought that
00:38:23 --> 00:38:26 that's prime target number one when
00:38:26 --> 00:38:28 searching for life beyond Earth. Um,
00:38:29 --> 00:38:31 would be to be listening for radio waves
00:38:32 --> 00:38:34 and, and Robert's right, the Square Kilometer
00:38:34 --> 00:38:37 Array will be capable for that. I think it be
00:38:37 --> 00:38:39 able to pick up airport radar uh
00:38:39 --> 00:38:42 as far away as 50 light years.
00:38:42 --> 00:38:45 Jonti Horner: Yes, it's an incredible, incredible tool and
00:38:45 --> 00:38:47 in fact this is what people have been doing.
00:38:47 --> 00:38:50 So this is the whole foundation of a subset
00:38:50 --> 00:38:52 of our science called seti, the Search for
00:38:52 --> 00:38:54 Extraterrestrial Intelligence. Often you
00:38:54 --> 00:38:56 describe this as a search for a needle in a
00:38:56 --> 00:38:57 hair stack, where you don't know what a
00:38:57 --> 00:38:59 needle looks like and you've never seen a
00:38:59 --> 00:39:02 hair stack before. So if you're trying to
00:39:02 --> 00:39:05 find life that is as technologically
00:39:05 --> 00:39:08 advanced as us, or more. So then there
00:39:08 --> 00:39:10 is an argument that listening for signals
00:39:10 --> 00:39:12 would be a good way to do it. And kind of
00:39:12 --> 00:39:14 corroborating that is the idea that we are
00:39:14 --> 00:39:17 broadcasting into the voyage, screaming like
00:39:17 --> 00:39:20 a toddler in a dark cave with our
00:39:20 --> 00:39:22 radio broadcasts and, um, our TV broadcasts
00:39:22 --> 00:39:25 and all this stuff with radio waves. And it's
00:39:25 --> 00:39:27 often argued that either the Berlin Olympics,
00:39:27 --> 00:39:30 which I think were 1936, or the coronation of
00:39:30 --> 00:39:33 Queen Elizabeth the Second in possibly 1952.
00:39:33 --> 00:39:35 1953, yeah, were the first broadcasts that
00:39:35 --> 00:39:37 were powerful enough that would be easily
00:39:37 --> 00:39:40 detected from elsewhere. So if you were
00:39:40 --> 00:39:42 magically able to take the Square Kilometer
00:39:42 --> 00:39:45 Array and place it as a star, ah, within
00:39:45 --> 00:39:48 about 80 light years of the Earth, you'd be
00:39:48 --> 00:39:49 able to listen in and watch the development
00:39:49 --> 00:39:52 of our technological society as our
00:39:52 --> 00:39:54 broadcasts get more numerous and more varied.
00:39:54 --> 00:39:56 You'd probably be able to broadcast back and
00:39:57 --> 00:39:58 say, please stop broadcasting, neighbours,
00:39:58 --> 00:40:01 we're sick of it. We want to know more about
00:40:01 --> 00:40:04 Scott and Charlene or whatever, um, people
00:40:04 --> 00:40:05 will be able to listen in. And so this gives
00:40:05 --> 00:40:07 everybody the idea that just like this
00:40:07 --> 00:40:09 question, we could do the same thing and we
00:40:09 --> 00:40:12 could try and tune in onto the broadcasts of
00:40:12 --> 00:40:15 other societies. And that's
00:40:15 --> 00:40:18 fundamentally the foundation of seti. Back
00:40:18 --> 00:40:20 when I was an undergraduate, back when I was
00:40:20 --> 00:40:22 at high school, in the early days of personal
00:40:22 --> 00:40:24 computing, there was a program called SETI at
00:40:24 --> 00:40:27 home, which was a way of distributing through
00:40:27 --> 00:40:30 cloud computing, packets of data obtained by
00:40:30 --> 00:40:32 radio telescopes to search for signals of
00:40:32 --> 00:40:35 radio broadcasts. And nothing was found.
00:40:35 --> 00:40:38 There are global usage of radio telescopes
00:40:38 --> 00:40:39 around the world to try and do this still.
00:40:39 --> 00:40:41 The most famous of them these days is the
00:40:41 --> 00:40:44 Breakthrough Listen Initiative, which was
00:40:44 --> 00:40:46 funded to the tune of $100 million starting
00:40:46 --> 00:40:49 back in 2015. So it's 10 years old now.
00:40:49 --> 00:40:52 That did a wonderful thing for Australia
00:40:52 --> 00:40:53 because the government at the time in
00:40:53 --> 00:40:56 Australia was our, um, less
00:40:56 --> 00:40:58 science friendly party, let's put it that
00:40:58 --> 00:41:00 way. And, uh, they were looking to save money
00:41:00 --> 00:41:03 by killing science, as often happens, and
00:41:03 --> 00:41:05 that's having knock on effects nowadays. But
00:41:05 --> 00:41:07 one of the things they wanted to do was close
00:41:07 --> 00:41:10 the dish, the Parks Radio Observatory,
00:41:11 --> 00:41:14 which is the Biggest, most iconic observatory
00:41:14 --> 00:41:16 building I think in Australia, famous for
00:41:16 --> 00:41:18 awesome movie the Dish with Sam Neill many
00:41:18 --> 00:41:18 years ago.
00:41:18 --> 00:41:20 Andrew Dunkley: And it's just down the road from.
00:41:20 --> 00:41:22 Jonti Horner: Where I live, just down the road. And there
00:41:22 --> 00:41:23 was a lot of upset that this wonderful
00:41:23 --> 00:41:25 facility was going to be mothballed and
00:41:25 --> 00:41:27 closed down to cut budgets,
00:41:28 --> 00:41:30 um, because, you know, they wanted to put
00:41:30 --> 00:41:32 more money into fossil fuel extraction to
00:41:32 --> 00:41:35 satisfy their donors or whatever. I, um, have
00:41:35 --> 00:41:38 views anyway, many do.
00:41:38 --> 00:41:41 Parks was saved by an injection of a very
00:41:41 --> 00:41:43 large sum of money from the Breakthrough
00:41:43 --> 00:41:45 Listen initiative, which has kept the
00:41:45 --> 00:41:47 telescope operating for another decade.
00:41:47 --> 00:41:49 There's a lot of awesome new science has come
00:41:49 --> 00:41:51 out of it as a result, but it is bought a
00:41:51 --> 00:41:53 certain fraction of the time of that
00:41:53 --> 00:41:55 telescope, which I think is about 40% to
00:41:55 --> 00:41:57 specifically point that telescope around the
00:41:57 --> 00:42:00 star to listen to radio broadcasts, to
00:42:00 --> 00:42:03 look for radio broadcasts from nearby stars.
00:42:04 --> 00:42:06 And there's been a number of papers come out
00:42:06 --> 00:42:09 on this over the years that detail
00:42:09 --> 00:42:11 the incredible work people have done. And to
00:42:11 --> 00:42:12 illustrate the challenge of these things,
00:42:12 --> 00:42:14 there's been a few occasions where people
00:42:14 --> 00:42:16 think there's been a potential signal only
00:42:16 --> 00:42:18 for it to be turned out to be something else.
00:42:19 --> 00:42:21 One example was that they thought they'd
00:42:21 --> 00:42:22 found a potential signal. And when they
00:42:22 --> 00:42:24 investigated more, it happened at the same
00:42:24 --> 00:42:26 time every evening and investigated more. And
00:42:26 --> 00:42:28 it was that the astronomers were walking
00:42:28 --> 00:42:29 across one of the building and putting their
00:42:29 --> 00:42:32 food in the microwave. Yes, the building was
00:42:32 --> 00:42:34 shielded. They were picking up the radiation
00:42:34 --> 00:42:36 from the microwaves, you know, so it's really
00:42:36 --> 00:42:39 hard to do today. We have found
00:42:39 --> 00:42:41 nothing. No. And ah, there are some arguments
00:42:41 --> 00:42:43 that, uh, it's very unlikely we will do.
00:42:43 --> 00:42:45 That's a needle in a hair sack thing.
00:42:46 --> 00:42:49 Firstly, we need to figure out where
00:42:49 --> 00:42:51 in the radio spectrum to look. And um, the
00:42:51 --> 00:42:54 radio wave frequency spectrum spans an
00:42:54 --> 00:42:56 enormous range. A lot of efforts have been
00:42:56 --> 00:42:59 focused around the hydrogen 21 centimeter
00:42:59 --> 00:43:01 line viewing. That has been an obvious place
00:43:01 --> 00:43:03 for people who are deliberately broadcasting
00:43:03 --> 00:43:05 to broadcast, because everyone will know
00:43:05 --> 00:43:07 about that. But in terms of accidental
00:43:07 --> 00:43:09 broadcasts like what we're doing on the
00:43:09 --> 00:43:11 Earth, there's no guarantee that another
00:43:11 --> 00:43:13 species would pick the same frequencies that
00:43:13 --> 00:43:16 we've chosen for the broadcast. So we might
00:43:16 --> 00:43:18 be listening to the wrong tune, we might just
00:43:18 --> 00:43:21 be listening at the wrong frequency. The
00:43:21 --> 00:43:22 other thing though is that, uh, the kind of
00:43:22 --> 00:43:24 broadcasting we've been doing for the last
00:43:24 --> 00:43:25 hundred years is incredibly energy
00:43:25 --> 00:43:28 inefficient because we broadcast in
00:43:28 --> 00:43:30 all directions at ah, once.
00:43:31 --> 00:43:34 To have a very small number of directions
00:43:34 --> 00:43:35 pick up that signal, you know, all your TV
00:43:35 --> 00:43:38 aerials Or whatever. It is much more
00:43:38 --> 00:43:40 efficient to do point to point communications
00:43:40 --> 00:43:43 or to send things through optical cables.
00:43:43 --> 00:43:45 So there is some argument that as your
00:43:45 --> 00:43:47 technology gets better, the amount of waste
00:43:47 --> 00:43:49 noise you broadcast to space will fall off.
00:43:49 --> 00:43:51 Yes. And so there's an argument that in the
00:43:51 --> 00:43:53 next 30 or 40 years the Earth will become
00:43:53 --> 00:43:56 radio silent again. So then there'll be this
00:43:56 --> 00:43:57 little bubble around the earth getting bigger
00:43:57 --> 00:43:59 and bigger where if you're in that bubble,
00:43:59 --> 00:44:01 you hear our radio broadcast, but then
00:44:01 --> 00:44:03 there's a smaller bubble in the middle where
00:44:03 --> 00:44:04 we go silent again.
00:44:04 --> 00:44:05 Andrew Dunkley: Yeah.
00:44:05 --> 00:44:06 Jonti Horner: And it may be that every technological
00:44:06 --> 00:44:08 species is only loud when it's in its
00:44:08 --> 00:44:11 infancy, when it is that toddler screaming
00:44:11 --> 00:44:12 that they don't want to leave the beach like
00:44:12 --> 00:44:15 the kid I saw yesterday. And eventually
00:44:15 --> 00:44:18 a uh, society learns to self regulate and
00:44:18 --> 00:44:21 has more efficient ways of broadcasting. So
00:44:21 --> 00:44:24 it is a fabulous question. If you want to
00:44:24 --> 00:44:26 learn more about it. I do recommend looking
00:44:26 --> 00:44:28 up and googling and reading around SETI as a
00:44:28 --> 00:44:30 project SETI at home and the Breakthrough
00:44:30 --> 00:44:33 Listen initiative. You can also look up
00:44:33 --> 00:44:36 an associated thing which is mete. Mete,
00:44:36 --> 00:44:39 which is, I think METE is the acronym which
00:44:39 --> 00:44:42 is a search for the artifacts of advanced
00:44:42 --> 00:44:45 civilizations. Oh, and I know colleague
00:44:45 --> 00:44:47 of mine in the US who's part of our planet
00:44:47 --> 00:44:50 search team has put out a few papers looking
00:44:50 --> 00:44:53 at things that appear in science fiction like
00:44:53 --> 00:44:56 Dyson spheres and ringworlds and
00:44:56 --> 00:44:58 what effect they would have on the light from
00:44:58 --> 00:45:00 their stars. So what the observational
00:45:00 --> 00:45:03 signatures would be not with any
00:45:03 --> 00:45:05 expectation that we'll ever find them, but
00:45:05 --> 00:45:06 because if we don't model what they would be
00:45:06 --> 00:45:09 like, if we ever see something that displays
00:45:09 --> 00:45:10 that odd behavior, we wouldn't know what it
00:45:10 --> 00:45:13 was. So it's again this very low
00:45:13 --> 00:45:15 likelihood of finding something, but very
00:45:15 --> 00:45:18 high reward if you ever do. I
00:45:18 --> 00:45:20 guess that people are actually actively
00:45:20 --> 00:45:22 thinking about what could we feasibly do
00:45:23 --> 00:45:25 as a technological civilization in the future
00:45:25 --> 00:45:27 with improving technology. How would that
00:45:27 --> 00:45:30 affect our environment around the sun? How
00:45:30 --> 00:45:32 would that affect the way that our planetary
00:45:32 --> 00:45:34 system pairs from around other stars? And uh,
00:45:35 --> 00:45:36 what would that look like if we saw a
00:45:36 --> 00:45:39 different civilization doing it? So that we
00:45:39 --> 00:45:41 have the predictions there so that when we
00:45:41 --> 00:45:43 get vast amounts of data from these all sky
00:45:43 --> 00:45:46 surveys, whether they be in the radio or
00:45:46 --> 00:45:48 whether they be in the optical, we can
00:45:48 --> 00:45:50 identify the oddities and figure out what
00:45:50 --> 00:45:52 they are. And similarly with a square
00:45:52 --> 00:45:54 kilometer array that will be pointing all
00:45:54 --> 00:45:57 over the sky, doing lots of astronomy, but
00:45:57 --> 00:45:59 the data from that will be analyzed by teams
00:45:59 --> 00:46:01 who are interested in could there be an alien
00:46:01 --> 00:46:04 signal buried in this. So you will get
00:46:04 --> 00:46:06 serendipitous imaging there because wherever
00:46:06 --> 00:46:08 it's looking, you get the data and you can
00:46:08 --> 00:46:10 survey that to see what there is. So it is
00:46:10 --> 00:46:13 something people are actively doing. You're
00:46:13 --> 00:46:14 onto something good there. And I can
00:46:14 --> 00:46:15 recommend, like I said, reading about
00:46:15 --> 00:46:18 breakthrough lists and reading about SETI to
00:46:18 --> 00:46:20 learn more about it, if that is what you're
00:46:20 --> 00:46:20 interested in it.
00:46:20 --> 00:46:23 Andrew Dunkley: Yeah, uh, it'd be uh, interesting to
00:46:23 --> 00:46:26 discover another race somewhere
00:46:26 --> 00:46:28 out there that's uh, built a megastructure,
00:46:28 --> 00:46:31 um, like, oh, I don't know, a space parasol
00:46:32 --> 00:46:35 array of some kind. Imagine that same
00:46:35 --> 00:46:37 problem. Someone else has solved it. Yeah,
00:46:37 --> 00:46:38 uh, we are going to be.
00:46:38 --> 00:46:40 Jonti Horner: Doing a little, little baby test of that
00:46:40 --> 00:46:42 potentially in the next 10 or 20 years if
00:46:42 --> 00:46:45 NASA ever gets its funding back. There is the
00:46:45 --> 00:46:48 Habitable Worlds Observatory that is
00:46:48 --> 00:46:51 looking at planets around other stars. And
00:46:51 --> 00:46:53 um, what they're proposing to do to allow
00:46:53 --> 00:46:55 them to gather light from planets the size of
00:46:55 --> 00:46:57 the Earth, uh, around stars like the sun, is
00:46:57 --> 00:46:59 reflectively fly a very giant,
00:46:59 --> 00:47:01 beautifully designed, very intricate,
00:47:01 --> 00:47:04 fractally edged, um, space
00:47:04 --> 00:47:06 parasol that would go out about 100
00:47:06 --> 00:47:09 km from the telescope and fly in formation,
00:47:09 --> 00:47:11 line up to block the light from stars so that
00:47:11 --> 00:47:13 we can see the planets going around them.
00:47:13 --> 00:47:16 Now that size of parasol would be way too
00:47:16 --> 00:47:18 small to impact climate change, but it's a
00:47:18 --> 00:47:20 really good tech demonstrator. It shows that
00:47:20 --> 00:47:22 we can do that and we can get the station
00:47:22 --> 00:47:24 keeping just much too small. And again, if
00:47:24 --> 00:47:26 people are interested in that looking up, the
00:47:26 --> 00:47:29 Habitable Worlds Observatory would be a
00:47:29 --> 00:47:30 good place to look. And there's some lovely
00:47:30 --> 00:47:32 videos of the animation of this thing being
00:47:32 --> 00:47:34 launched and unfolding and moving out in
00:47:34 --> 00:47:37 space. And they've even done tests in labs
00:47:37 --> 00:47:40 for mini versions of it on long corridors to
00:47:40 --> 00:47:41 prove the concept works.
00:47:42 --> 00:47:45 Andrew Dunkley: All very cool, very cool indeed. And uh, a
00:47:45 --> 00:47:46 cool question too, Robert. Thanks for sending
00:47:46 --> 00:47:48 it in. And if you would like to send us
00:47:48 --> 00:47:50 questions, don't Forget our website
00:47:50 --> 00:47:52 spacenutspodcast.com
00:47:52 --> 00:47:55 spacenuts IO and
00:47:55 --> 00:47:57 uh, click on the AMA link and you can send us
00:47:58 --> 00:48:00 text, uh, and audio questions, uh, through
00:48:00 --> 00:48:03 that system. And uh, we'd be happy to get
00:48:03 --> 00:48:04 them and we'll do our very best to answer
00:48:04 --> 00:48:06 them. Sometimes we get the same questions,
00:48:07 --> 00:48:10 um, which is not unusual if people sort of
00:48:10 --> 00:48:12 hone in on a topic. Uh, so we will,
00:48:12 --> 00:48:14 um, if we don't answer your question, it's
00:48:14 --> 00:48:17 possibly because we've already done it, uh,
00:48:17 --> 00:48:19 but we do redo questions from time to time
00:48:19 --> 00:48:21 because they keep coming up, um, particularly
00:48:21 --> 00:48:24 black hole questions. We quite often get a
00:48:24 --> 00:48:26 repeat. Might be a couple of years later, but
00:48:26 --> 00:48:28 we get a repeat of a question we've already
00:48:28 --> 00:48:30 covered. So we'll, we'll sometimes redo them.
00:48:31 --> 00:48:32 But, uh, good to hear from you, Robert.
00:48:32 --> 00:48:34 Thanks to everyone who contributed and thanks
00:48:34 --> 00:48:37 to you, Jonti, for having a crack at the
00:48:37 --> 00:48:37 answers.
00:48:38 --> 00:48:39 Jonti Horner: That's all good. It's what I'm here for. And
00:48:39 --> 00:48:42 it's fun to face new and interesting
00:48:42 --> 00:48:42 questions.
00:48:42 --> 00:48:45 Andrew Dunkley: It is indeed. Uh, we'll see you on the next
00:48:45 --> 00:48:47 episode. Jonti, uh, Horner, professor of
00:48:47 --> 00:48:49 Astrophysics at the University of Southern
00:48:49 --> 00:48:51 Queensland. And thanks to Huw in the studio.
00:48:52 --> 00:48:55 Not, um, sure you're aware that Huw used to
00:48:55 --> 00:48:57 work in radio. That's how we actually met. In
00:48:57 --> 00:49:00 fact, he was working at a radio station, uh,
00:49:00 --> 00:49:03 in Newcastle in New South Wales when I was a
00:49:03 --> 00:49:04 kid and I did job experience there. And
00:49:04 --> 00:49:06 that's how I met Huw originally, when I was
00:49:06 --> 00:49:09 about 13 years old or something.
00:49:09 --> 00:49:12 Anyway, he's an old radio man these days
00:49:12 --> 00:49:15 and, uh, when it comes to radio waves,
00:49:15 --> 00:49:17 he feels that that means he should stand out
00:49:17 --> 00:49:20 the front waving at traffic. That's why he's
00:49:20 --> 00:49:22 not with us today. And he may never come
00:49:22 --> 00:49:24 back. And from me, Andrew Dunkley, thanks for
00:49:24 --> 00:49:27 your company. I'll see you on the next
00:49:27 --> 00:49:29 episode of Space Nuts. Bye. Bye.
00:49:30 --> 00:49:32 Jonti Horner: You'll be listening to the Space Nuts.
00:49:32 --> 00:49:33 Robert: Podcast.
00:49:34 --> 00:49:37 Jonti Horner: Available at Apple Podcasts, Spotify,
00:49:37 --> 00:49:40 iHeartRadio or your favorite podcast
00:49:40 --> 00:49:42 player. You can also stream on demand at
00:49:42 --> 00:49:43 bytes. Com.
00:49:44 --> 00:49:46 Andrew Dunkley: This has been another quality podcast
00:49:46 --> 00:49:47 production from Bytes.
00:49:47 --> 00:49:48 Jonti Horner: Com.
00:49:48 --> 00:49:48 Speaker C: Um.