Feb. 3, 2025

Cosmic Questions, Solar Mysteries & Lunar Dreams: #492 - The Great Space Q&A

Cosmic Questions, Solar Mysteries & Lunar Dreams: #492 - The Great Space Q&A

Space Nuts Episode 492: Tidal Locking, Solar Mysteries, and Moon Travel
Join Andrew Dunkley and Professor Jonti Horner in this engaging Q&A edition of Space Nuts, where they tackle a variety of cosmic questions from our curious listeners. From the...

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Space Nuts Episode 492: Tidal Locking, Solar Mysteries, and Moon Travel
Join Andrew Dunkley and Professor Jonti Horner in this engaging Q&A edition of Space Nuts, where they tackle a variety of cosmic questions from our curious listeners. From the complexities of tidal locking in celestial systems to the intriguing heat discrepancies in the Sun's layers, and even how to get to the Moon, this episode is filled with fascinating insights that will deepen your understanding of the universe.
Episode Highlights:
- Tidal Locking Explained: Jake from Tennessee asks about the possibility of tidal locking between stars and their orbiting planets. Jonti dives into the mechanics of tidal interactions, using examples from our own solar system, including the Earth-Moon relationship and Pluto's moons.
- Solar Mysteries: Clint from Georgia raises a thought-provoking question about the Sun's corona, which is millions of degrees hotter than its surface. Andrew and Jonti explore the latest theories on how gravitational interactions and magnetic fields could contribute to this phenomenon.
- How to Get to the Moon: Emily from Melbourne wants to know how humans travel to the Moon. Jonti breaks down the journey, explaining the rocket science behind space travel, the challenges of exiting Earth's atmosphere, and the exciting prospects of future lunar missions.
- Listener Engagement: Andrew and Jonti encourage listeners to submit their own questions, highlighting the importance of curiosity in the scientific community.
For more Space Nuts, including our continually 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.
00:00 - Introduction to the episode and topics
02:15 - Discussion on tidal locking and celestial mechanics
10:30 - Insights into the Sun's corona and heat discrepancies
18:00 - How to travel to the Moon explained
26:45 - Listener Ash engagement and questions
30:00 - Closing thoughts and future episodes
✍️ Episode References
NASA's Lunar Missions
https://www.nasa.gov/
Tidal Locking
https://en.wikipedia.org/wiki/Tidal_locking
Solar Corona Studies
https://www.nasa.gov/solar-system/

Become a supporter of this podcast: https://www.spreaker.com/podcast/space-nuts--2631155/support.

 

 

WEBVTT

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By there, Andrew Dunkley here and you're listening to Space

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Nuts Q and a edition. Glad to have your company

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once again. On this episode we will be answering an

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array of questions on very different topics. Jake is asking

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us about tidle Locke. That's not something to hold back

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the water in the Thames River, No, something completely different.

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Clint wants to talk about the heat of the sun. Emily,

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Sandy's daughter in Melbourne, wants to get to the moon

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and we're going to tell her how. And Fenton has

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asked a vast array of questions which could probably fill

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an episode on their own about the radiation of Jupiter.

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That's all coming up on this edition.

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Of Space Nuts Channel ten nine ignition Space Nuts or

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three two one spaces and I reported Neil's good and.

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Joining me once again is not Professor Fred Watson because

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he is overseas looking at the sky up in the

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Northern Hemisphere. But with us is Professor John D. Horner,

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Professor of astrophysics at the University of Southern Queensland. Johnty, Hello, Hey,

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how are you going? I am well, we're working on

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getting you your own intro, but we're in a time

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of year where all the radio stations in Australia want

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new jingles, and our studio producer who does all that

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work is flat out at the moment, so we've been

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put on the back burner, I think. But you can

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understand why all the radio stations want to ramp up

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how they sound so that they can get new audience.

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I worked in radio for forty years. I'm pretty sure

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changing the jingle doesn't actually do much, but just my

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observation in forty you'll look at it just in time

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for Fred to get buck. Yes, yes, I think that's

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exactly what I was about to say.

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Stole my joke.

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Never mind, But what we'll do right now is look

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at some audience questions. I love this particular episode every

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week because it's the audience's chance to get involved. And

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we've got a few audio questions coming up. But our

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first one comes from Jake, who actually sent this question

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via Facebook Messenger, which we don't often catch because we

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don't monitor it as much as we as we probably should.

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But we just haven't got the person power. But I

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just happen to be sort of on my iPad the

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other day and went, oh, hang on a minute, there's

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a little one there. Greetings from Tennessee, USA, Tennessee, home

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of the Titans.

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I know that.

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Several two body systems are in various stages of tidal locking.

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I was wondering if for star or planet with several

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orbiting bodies can even become tidally locked with a particular one.

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For example, can the Sun become tidally locked to one

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of our planets? Likewise, can Jupiter become tidally locked to

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one of its moons? I assume that if such tidal

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lock can occur, the larger body becomes locked with its

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most gravitationally attractive orbiting body. But if that's the case,

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how are the other orbiting bodies affected? Love the show

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And that was a question from Jake Tyler. I've got

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a feeling that he's going to some of the things

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he said in the question are the reality.

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Yes, So there's a lot of complete sit to this.

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It's a really really good question. Now we're familiar with

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tidal locking. Anytime we look up at the annoying source

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of light pollution in our scar that is the moon,

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you know, keeps one face pointed towards us all the time,

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with a little bit of rock and roll because it's

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been nudged by everything else. It's not on a perfectly

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circular orbit, but it essentially keeps the nest out of

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the moon festus towards the far side, festers away. It rotates.

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One something SUTs this and exactly the same time it

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takes to go around the Earth, essentially, so it's turning

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as it goes. The Earth is slowing down in its

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rotation as the Moon is getting nudged away. There's this

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tidal interaction between them that I always visualize essentially as

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being the result of the tidal bulges. The Moon res

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is on the Earth, so we get high tid and

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a low tide every day, and I view those a

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bit like break blocks on a wheel. They're kind of

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applying friction to the Earth because the Earth is turning

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under them once every twenty four hours or so, but

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those tidal bulges are doing one lap every twenty seven

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twenty eight days because they are tied to the location

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of the Moon and the Sun. So those bulges are

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drugged along by the friction of the Earth. They're pulled

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slightly away from that line between the Moon and the Sun,

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which means that they are then pulling a little bit

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on the Moon and causing the Moon to speed up,

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which means it moves away. They've got this transfer of

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energy and momentum between the rotation of the Earth and

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the orbit of the Moon, so the Earth's spin is

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slowing down and the Moon is moving further away. Now,

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in theory, if we could carry on full long enough,

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that would eventually slow the Earth rotation down such that

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it matched the orbital period of the Moon. There is

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some debate though, a that will not happen quick enough

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for it to happen within the age of the Solar

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System that's left. But there's also some debate as to

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whether that would happen before the Moon gets far enough

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away to escape the Earth gravity. So in the case

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of the Earth Moon system, it's not going to happen,

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but it illustrates that it could so move out further

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out of the Solar System to Pluto, the dwarf planet.

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And we talked about Pluto a couple of weeks ago

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having this big companion called Charon. Yeah, Pluto actually though

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has about five minutes. It's got Charen, which is huge,

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and then it's got four little ones in Kerberos, knicks, sticks,

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and hydra I think they're called, and then smaller ones

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further out. Now Pluto and Caron are tidly locked. Karen

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spins once in the time it takes to all bit

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the center of mass between Pluto and Karen once, so

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it always keeps the same side facing towards Pluto in

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just the same way that the Moon does going around

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the Earth. But Pluto has also tidally locked with Charon,

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so Pluto keeps the same face pointing towards Karen all

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the time. So that's a prime example of the kind

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of system Jake was asking about a case where the

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biggest body has locked to the second biggest body and

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they're both locked together, and there are other things in

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the system. When it comes to plantary systems, and when

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it comes to the more generality of it, it gets

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a bit more complicated. So there's a few things going on.

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It's not necessarily the most massive body going around a

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star that would be the one that it tidally locked up,

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because the distance is important as well, and tidal forces

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fall off incredibly rapidly as a function of distance, much

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more quickly than the asquad fall off of the gravitational attraction.

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I think it's either an arcugorn ark to the power

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for setup, which means that the closer you get to

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the star, the much more strongly you tidally interact. Now

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we see this with exo planets. We can see the

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exo planets that are very close to their stars are

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tidally locked. The ones that are further away are probably not.

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But we also see it in the form of tidal

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circularization of orbits. So you get a planet that is

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flung onto an elongated orbit where the closest point to

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the star is very near the star because of the

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degree to which tidal forces vary as a function of distance.

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That means a star will interact much more strongly with

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the planet in a tidal sense when it's near the

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closest approach, and when it's far away. That means that

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you will get a you'll get an attempt to tidally

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lock the planet, so the planet's rotation will be getting

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meedged into a rotation period that matches the overal period.

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But at the same time you get this dissipation of

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energy that tries to make the orbit more circular, and

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that dissipation of energy is happening at the perry apse

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of the orbit, the point of the orbit where it's

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closest to the star. The result of this is that

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that all bit gets more and more circular by bringing

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the appo apps the furthest point from the star closer

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to the star. So it ends up being circularized at

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that closest approach distance, and that happens more quickly than

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the tidal locking process. And that's the result of the

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fact that the tidal forces fall off much more strongly

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as a function of distance. We haven't yet found any

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stars that we think are definitely tidally locked to their planet.

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Now.

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Part of this is down to the mass difference, so

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the small thing will tidally lock on much more quickly

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than it's bigger companion. That's what we're seeing with the

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Earth and the Moon. But it's not beyond the bounds

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of possibility. And there are suggestions that tidal interactions between

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really massive planets planets a lot bigger than Jupiter, and

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stars when the planets are really close in, can have

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a significant impact on the spin of those stars and

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also the energy dynamics of what's going on in their interiors.

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Not totally my area of expertise. I've got a flag that,

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but this is something that people have having to think

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about when they come to looking at ways of measuring

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the age of stars. Now there's a few ways you

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can do this. I've got colleagues at UNISQ who work

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on astero seismology. They're looking at how stars wobble and wibble,

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ringing like bells that have been struck, and you can

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look at the different frequencies at which they're wobbling and

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wibbling to learn a lot about their interior. And that

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kind of study can give you an estimate of the

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ages that's really quite accurate, but it's really resource intensive.

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You need to stare at a star for a long

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time doing a lot of observations. If you're trying to

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just get the age of stars in general. There's a

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technique called gyro chronology or gyro chronology, which is essentially

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measuring the rotation speed of the star and using that

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to get a first estimate of its age, which will

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have quite big uncertainties, but seems to do a reasonably

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good job. And the idea here is that when stars

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are bond, they're bond from material collapsing, in which spins

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faster and faster. So typically a newly born star will

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spin quite quickly every day or two, but over billions

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of years, all the masts losing through the stellar wind

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what kind of act as a break on the star's rotation,

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taking away that angular momentum, causing its spin to slow

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down over time. So if you know the degree to

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which stars slow down as a function of time, and

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you measure how quick a star's spinning, it gives you

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an estimate of its age. BECs an old star will

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spin slower than a young star, but if that star's

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got a really close in planet that's interfering with it tidally,

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that will impact that process. Yeah, so there's a lot

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of aspects to this. I appreciate I'm going a little

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bit off topic from Jake's question, but it shows you

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the complexity of it. And it's why it's such a

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good question because it's something that we don't know the

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final answer to. It's going to depend very much on

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each individual system. For the Earth and the Moon, we're

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probably never going to get fully tidally locked to the Moon,

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but we know that when the dinosaurs walk the Earth,

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the Earth was spinning quicker and we've had independent verification

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of that. Not only do we know that from the

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tidal motion of the Moon moving away, we can measure

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the speed of the Moon's moving away, but there are

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also measurements that have been made of fossil beds that

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show that there were about three hundred and eighty three

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hundred and ninety days a year back in the Cretaceous. Now,

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the soorbital period hasn't changed, as mentioned in the number

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of seconds. So how do you get more days in

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the year. You get more days in the year by

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making the days shorter. So that's the direct outcome of

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that tidal reaction between the Earth and the Moon. Pluto

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is a stage further along that's fully lopto. You've got

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an interesting case in our sol system of mercury, which

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is trapped in a three to two spin orbit resonance,

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so it's tidally locked, but it's not locked in one

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to one, and the only reason that works is that

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mercury is on an elongated orbit and is also not

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a perfectly spherical object. Gets quite complicated, yeah, but this

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gets odder the more you study it basically, and there's

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a lot of depth to it, so it makes it

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a fabulous question.

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He certainly is. Thank you, Jake. A question popped into

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my head while you were talking. You talk about the

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effect of the moon on Earth's oceans, the tides. Would

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it be to an too extreme a thought to suggest

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that the tides are actually just a slow motion tidal wave.

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You could possibly think of that way. I never have

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done before, but it's an interesting one because the phrase

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tidal wave in itself is quite misleading because they're not

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really waves in the same sense as the waves we

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see on the beach. So this is where when you

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see disaster movies and you get this enormous toll breaking wave,

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that's not really what a tidal waves like. A tidal

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wave is a huge body of water rising and falling.

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So it's more like the surface of the ocean getting

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higher or lower, and it's probably when it gets really

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close to the coast that that can break. So I

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know people who are into geophysics and ocean dynamics who

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get grumpy at disaster movies for getting tidle waves totally

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totally wrong. But in that sense, our tides are very

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much like that. It's the same kind of process of

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water rising and falling and a huge body of a

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to doing that means it slushes around a bit as well.

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Very similar thing and tied into this. Of course, when

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the moon was closer to us, which it had to

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be in the past, when the days were shorter, the

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tides were higher and more extreme, and that's tied into

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arguments people have had about the origin of life, suggesting

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that the origin of life happened in the intertidal region

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on the car which would have been larger when the

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tides were higher, but the tides were happening more quickly

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as well, so the inundation and drying out happened on

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a quicker time scale. So first ample of the move.

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Yeah, it's going, it's intriguing. It's an amazing sign. Thank

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you again, Jake Gregg. Question glad I happened across it

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the other day. This is Space Nuts. Andrew Dunkley here

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with Professor Johnny horn Apps. Okay, we take all for

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Space Nuts. Let's go to our next question, which comes

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from Clint.

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Hi've Fred, Hi, Andrew, this is Clint from Rome, Georgia

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US say love the show, Happy New Year. My question though,

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comes from the Sun. We know the surface of the

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Sun is around six thousand degrees celsius, but the corona

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is much hotter millions of degrees. I know scientists are

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still puzzled with this phenomenon, but my question is, could

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this be due to the gravitational pullback towards the Sun

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that is causing some kind of friction on leaving matter

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that the Sun is losing or projecting. Just a thought

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I have when reading how the Parker solar probe came

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its closest to the Sun earlier last year or this year,

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depending on when you're listening to this, and they use

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its own gravity to power it quickly through the surface

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of that corona. Just a quick question I had while

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exploring that.

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Thank you, Okay, thanks Clint.

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Love the accent.

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Now, I know the Sun isn't your main area, but

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I'm guessing you've done your homework on question.

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A little bit. It's actually a real head scratcher because

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it's pushing the boundaries of what we know, and that's

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what I really love. So, you know, the first thing

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for me to say here, and I think it's always

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important to acknologe it, is that I don't know the

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answer here. Fully, I'm not an expert. The part of

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the badia of science is asking questions we don't know

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the answer to. That's what makes a scientist. If we

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already knew the answer to everything, it'd be really, really boring.

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And the Sun's corona, and by extension, the corona of

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all the stars that we see, is so an ongoing problem.

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So exactly as you said, the photosphere the visible surface

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of the sun, that area of the Sun is about

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eight hundred and six thousand degrees center grade celsius roughly

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not precise, but it's high density. So that's essentially the

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final surface you can see before like gets scattered. So

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the analogy often use here is like looking at a

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fog bank. A fog bank is not solid, but when

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you're on a foggy or a mystic day, people measure

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the distance that you can see, and the denswer the

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fog is the shorter of that distance. Is of course,

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you're looking at particles, and essentially the photosphere of the

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Sun is the last surface of which your average photon

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of light would hit a particle and be scattered. So

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once it reaches this point, you can escape space. And

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so that gives us this illusion of a solid surface,

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when in fact you just get into a denser piece

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of gas. So the gas in the photosphere is quite

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dense and a huge amount of radiation comes out from it.

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So when people look at the Sun in the sky,

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and there's always the usual caveat here of please don't

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do that, because it's a very good way of damaging

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your eyes permanently. But when you see the Sun, when

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you see a photograph of the Sun, that surface you're

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seeing is because there's a high density, so there's a

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huge amount of radiation coming in coming out of it.

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When we get in the totally eclips of the Sun,

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we suddenly see this beautiful diaphanous, very variable area around

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the Sun we call the corona, and that's a much whiter,

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bluer light. When you get color photos which is indicative

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of a much higher temperature, and you think, what, it's

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a higher temperature. The amount of energy that you get

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from a photon is related to the temperature, to the

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power for really incredible more energy. So shouldn't the corona

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be brighter than the surface of the Sun. Why don't

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we see it? And the answer is because the individual

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photons are much more energetic, but there's far, far, far

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far less gas set, so there's much less flux. You've

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got higher energy photons, but a lot less of them,

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so you can only see it when the sun's blocked out.

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But the corona is incredibly hot. It's like a million

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two million degrees, this incredibly tenuous gas, hot enough that

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the individual atoms, the individual nuclei are traveling quick enough

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that they'll escape the Sun's gravity and flood out into

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the space. So corona links in with the solar wind,

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they're connected, and it's been an outstanding, really long term

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question of how on Earth the corona is heated to

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those temperatures, What on Earth's going on?

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Now?

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The gravity idea, the idea of friction. There will be

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a little bit of friction, So any particles entering into

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the corona that are colliding with things will transfer energy

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to the to the atoms and nuclei that they're impacting,

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and you can get some degree frictional heating there, but

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that's going to be a very very very small amount.

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It's not going to be anywhere near enough to do this,

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but you're right, it will probably contribute a bit of

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energy to this. And we know full well that there

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is continually dust, a material falling into the sun. The

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most spectacular example of that are the sung graysing commets

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that go in and fall apart and fragment, dumping a

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huge amount of dust and gas into that corona in

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a localized event. Now, the thing that to me, from

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a science education background, from the way I've been trained

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to think about problems, to say that Clint's idea doesn't

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quite work, would be to look at the distribution of

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temperature in the corona, so the bulk of the mass

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entry into the corona would be the rarer events like

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the breakup of sungras in common you get one hundred

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00:19:01.240 --> 00:19:03.680
meter sized object breaking into dust, and that would inject

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a lot of material in one particular place. So if

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the mechanism Clint was suggesting was the main one, you'd

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expect that one bit of the corona to then become

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much hotter and much brighter than the rest, and we

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don't observe that. So that to me is a very

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big tell tale that it's not in falling material heating

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it up, because in falling material will be episodic and localized.

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And so you get one bit of the corona bright,

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then another bit, then another bit, and instead the corona

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seems to be uniformly hot. Its shape and structure changes

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though through the solar cycle, and that's tied to the

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magnetic fields, and that seems to be a hint at

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what's actually going on. Now. It's absolutely right, we don't

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know the final answer, but I've been looking around and

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there was a bit of work came out back in

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twenty twenty three I think it was that has come

379
00:19:49.200 --> 00:19:53.119
up with a potential part of the answer. So the

380
00:19:53.200 --> 00:19:57.440
answer here is linked to what researchers have called low

381
00:19:57.519 --> 00:20:03.359
amplitude decaleless kin cost relations. All right, again, we're really

382
00:20:03.400 --> 00:20:06.759
good at naming things, lad cause I guess if you

383
00:20:06.799 --> 00:20:12.039
really wanted an acronym there. So the corona is tied

384
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in with the magnetic field of the Sun, and as

385
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the sol cycle goes on, the magnetic field gets more

386
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and more tangled up, and you get loops and kinks

387
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happening near the surface of the son, often tied with

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sun spots, and this is all tied in with flares

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and coronal mass ejections, things like this. What this is saying,

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I think, is that you get oscillations in those magnetic

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field lines, and the oscillations carry energy from the surface

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into the corona and can deposit it there. Now, normally

393
00:20:40.319 --> 00:20:42.519
those oscillations would be short lived, so you'd only have

394
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a short period of time to deposit energy, so they

395
00:20:44.559 --> 00:20:48.240
wouldn't be very efficient. But these studies, these observations found

396
00:20:48.720 --> 00:20:51.240
a kind of oscillation on those magnetic field lines that

397
00:20:51.400 --> 00:20:55.240
is of low frequency, so not carrying much energy per second,

398
00:20:55.880 --> 00:20:58.920
but can be long lived because they are be careless,

399
00:20:58.960 --> 00:21:01.559
they're not decaying. So get these oscillations that set up,

400
00:21:01.799 --> 00:21:04.920
they keep going for minutes or hours, and that gives

401
00:21:04.960 --> 00:21:07.160
them a long time to put energy into the corona.

402
00:21:07.200 --> 00:21:10.680
So the authors of this worth are talking about the

403
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fact that such oscillations, which seem to be really common

404
00:21:14.599 --> 00:21:18.240
from their observations, could act to deposit a large amount

405
00:21:18.279 --> 00:21:20.279
of energy in the corona. So it's a way of

406
00:21:20.319 --> 00:21:22.920
transferring energy from the magnetic field of the Sun into

407
00:21:22.960 --> 00:21:25.920
the corona, which then carries that energy away into space,

408
00:21:26.480 --> 00:21:28.880
which ties into what we were talking about before actually

409
00:21:28.880 --> 00:21:32.319
in the gyrochronology, because it's that energy that has been

410
00:21:32.359 --> 00:21:35.119
lost that is transferring angular momentumway into space as well

411
00:21:35.160 --> 00:21:38.160
and causing that to slow down. So it is all

412
00:21:38.319 --> 00:21:42.160
linked together. Now that study used data from European Space

413
00:21:42.200 --> 00:21:47.400
Agency Solar Orbiter NASA's Solo Dynamics Observatory, and they found

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00:21:47.519 --> 00:21:50.480
one of these oscillations that lasted for four minutes. Now

415
00:21:50.519 --> 00:21:53.480
four minutes doesn't sound long, but a kink a wobble

416
00:21:53.599 --> 00:21:55.240
going off four minutes has a lot of time to

417
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deposit energy into space.

418
00:21:57.119 --> 00:21:57.359
Yeah.

419
00:21:57.920 --> 00:21:59.680
Read more about this. You can have a look online.

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It wasublished i think September twelve, twenty twenty three in

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00:22:03.519 --> 00:22:07.559
Nature Communications, with the leader author being and apologies for

422
00:22:07.599 --> 00:22:10.240
the pronunciation there. It's a solo physicist at the University

423
00:22:10.240 --> 00:22:15.680
of Warwick in the UK, and it's Valerie makariyakov Na

424
00:22:15.880 --> 00:22:20.400
aariakr V And you can find the findings online in

425
00:22:20.480 --> 00:22:24.200
Nature Communications. Their paper will do an infinitely better job

426
00:22:24.240 --> 00:22:26.359
of explaining what's going on than I just did, because

427
00:22:26.359 --> 00:22:29.640
they're the experts. But that seems to be the latest

428
00:22:29.799 --> 00:22:34.480
entry in our attempts to answer the question of WTF. Essentially,

429
00:22:34.480 --> 00:22:36.799
what on Earth is going on with the corona? How

430
00:22:36.839 --> 00:22:40.200
does it work? And that's how sounds regretted us. You know,

431
00:22:40.240 --> 00:22:41.920
we don't know all the answers yet, and that's why

432
00:22:41.920 --> 00:22:44.880
this is such a fabulous question. And what Clint has

433
00:22:44.920 --> 00:22:48.119
done in coming up with a potential hypothesis for what

434
00:22:48.160 --> 00:22:50.359
happens is how scientists actually works. So we do just

435
00:22:50.400 --> 00:22:52.799
what Clint did. We come up with an idea this

436
00:22:52.920 --> 00:22:55.359
I think is something that could contribute. This is how

437
00:22:55.359 --> 00:22:57.960
it could work. And then what happens is that we

438
00:22:58.039 --> 00:23:01.480
make predictions from that, which is how I extrapolated it,

439
00:23:01.519 --> 00:23:04.319
which is that if it's linked to in following material

440
00:23:04.400 --> 00:23:07.000
that's a man driver, what would we see, Well, we'd

441
00:23:07.000 --> 00:23:09.440
see the plasus where you get a big fall of material,

442
00:23:09.440 --> 00:23:12.559
you get a bright outburst of energy and they will dominate,

443
00:23:12.680 --> 00:23:15.440
and we don't see that, so that theory doesn't work.

444
00:23:15.519 --> 00:23:18.440
We met testable predictions and tests and this is just

445
00:23:18.599 --> 00:23:20.559
another step in the way to work into that answer.

446
00:23:20.559 --> 00:23:23.640
So I think it's a wonderful question. It is approaching

447
00:23:23.680 --> 00:23:25.480
something that we don't have all the answers for you,

448
00:23:25.559 --> 00:23:27.880
but hopefully my answer helps a little bit and understanding

449
00:23:28.279 --> 00:23:30.000
just what's going on and what isn't happening.

450
00:23:30.720 --> 00:23:34.920
Yeah, it also shows how complex these these things are.

451
00:23:35.000 --> 00:23:37.480
I mean, the Sun is the most studied star in

452
00:23:37.519 --> 00:23:39.680
the universe as far as we're concerned, and we still

453
00:23:39.680 --> 00:23:43.920
haven't figured it out. So there's so many different kinds

454
00:23:43.960 --> 00:23:47.039
of stars and they might not all be doing the

455
00:23:47.079 --> 00:23:50.079
same thing. So yeah, there's much to learn. Clink, great question,

456
00:23:50.279 --> 00:23:51.440
Thanks for sending it in.

457
00:23:51.920 --> 00:23:52.960
This is Space Nuts.

458
00:23:53.000 --> 00:24:03.000
Andrew Dunkley here with Professor Johndy Horn. Ask space Nuts, Johnny.

459
00:24:03.039 --> 00:24:07.319
Our next question comes from one of our younger audience members,

460
00:24:07.640 --> 00:24:11.519
and I will hand it over to Sandy and Emily.

461
00:24:11.880 --> 00:24:16.079
Good day, friend, Andrew. It's again thank you for answering

462
00:24:16.079 --> 00:24:20.160
my last question. That gag about the asteroids pretty funny.

463
00:24:21.599 --> 00:24:25.480
Now today my four year old daughter Emily wants to

464
00:24:25.519 --> 00:24:27.920
ask a question, so I'm going to pass it on

465
00:24:27.960 --> 00:24:31.720
to her. How good week, Gay to Nay. Good job, Emmy,

466
00:24:32.000 --> 00:24:34.839
thank you, Thank you for Andrew. Hopefully you can answer

467
00:24:34.839 --> 00:24:36.400
this question for us. Jeers.

468
00:24:37.039 --> 00:24:40.000
Well, I won't be Fred or Andrew, it will be

469
00:24:40.079 --> 00:24:44.440
Johnty and Hi Emily and Sandy's one of our regular contributors.

470
00:24:44.440 --> 00:24:50.160
But great to hear from Emily. A giant ladder. Probably not.

471
00:24:50.920 --> 00:24:53.319
It's an awesome question and a really good one, Emily,

472
00:24:53.359 --> 00:24:57.079
so thank you very much for that. It's difficult. It's

473
00:24:57.319 --> 00:24:59.920
the very short thing. So traveling into space is chilling,

474
00:25:00.799 --> 00:25:03.920
and this is why we never managed it until nineteen

475
00:25:03.960 --> 00:25:06.519
fifty seven when they launched Sputnik one, which was the

476
00:25:06.559 --> 00:25:09.400
first thing that went into orbit around the Earth. The

477
00:25:09.400 --> 00:25:12.200
Moon's further away. The Moon, on average is about three

478
00:25:12.319 --> 00:25:16.680
hundred and eighty four thousand kilometers away. What that means

479
00:25:16.720 --> 00:25:18.519
is if you want to get there in a reasonable

480
00:25:18.519 --> 00:25:20.960
amount of time, you need to travel really really quickly.

481
00:25:21.640 --> 00:25:24.240
If you were to travel on the highway, you're going

482
00:25:24.240 --> 00:25:27.079
at one hundred kilometers an hour, it would take you

483
00:25:27.319 --> 00:25:30.200
something like three thousand, eight hundred hours to drive there

484
00:25:30.279 --> 00:25:32.680
driving at that speed. And I think we've all got

485
00:25:32.680 --> 00:25:34.880
better things to do than that. So obviously we can't

486
00:25:34.960 --> 00:25:36.599
drive to the Moon, even if we had a road

487
00:25:36.680 --> 00:25:39.000
or we had a ladder. What we need to do

488
00:25:39.079 --> 00:25:41.880
instead is find a way to get to go very

489
00:25:41.960 --> 00:25:45.599
very quickly, and then travel there more rapidly. And put

490
00:25:45.599 --> 00:25:48.599
that in perspective. When the first people walked on the

491
00:25:48.640 --> 00:25:51.720
Moon back in the late nineteen sixties, took them about

492
00:25:51.759 --> 00:25:54.279
three days to get there, so they were traveling a

493
00:25:54.279 --> 00:25:56.720
lot quicker than you go when you're driving to school

494
00:25:56.799 --> 00:25:57.480
or driving.

495
00:25:57.240 --> 00:26:00.000
To work, unless you go piplight Sony car.

496
00:26:00.960 --> 00:26:03.400
Yes, even with the p plates, it's a push. I mean,

497
00:26:03.440 --> 00:26:05.599
I wish I could do my commute at this kind

498
00:26:05.599 --> 00:26:08.039
of speed because it will make life a lot easier. Yes,

499
00:26:08.799 --> 00:26:10.960
so there's a few problems with that. You've got to

500
00:26:11.000 --> 00:26:14.519
get to a very high speed, which our cars just

501
00:26:14.559 --> 00:26:16.519
can't do. But you don't want to just get to

502
00:26:16.559 --> 00:26:21.000
that speed instantaneously because the acceleration would be really really

503
00:26:21.079 --> 00:26:24.119
violent and really really painful. And you feel this when

504
00:26:24.119 --> 00:26:27.319
you feel you know, somebody driving maybe Sandy's driving Emily,

505
00:26:28.279 --> 00:26:31.079
and they accelerate from the traffic lights. So the harder

506
00:26:31.079 --> 00:26:33.480
they accelerate, the more you're pushed back into your seat.

507
00:26:34.359 --> 00:26:36.640
And so the more you're changing speed, the more you

508
00:26:36.720 --> 00:26:39.920
feel that. And this is something fighter pilots need to

509
00:26:39.960 --> 00:26:43.240
train to practice with because when a fighter jet does

510
00:26:43.240 --> 00:26:47.559
a really sharp turn, the pilot can pass out because

511
00:26:47.599 --> 00:26:50.039
I think g forces are so extreme that all the

512
00:26:50.039 --> 00:26:52.599
blood is pushed out of their brain and they kind

513
00:26:52.640 --> 00:26:54.480
of fall asleep, and that's not good. So they have

514
00:26:54.559 --> 00:26:57.559
special clothes to deal with this. So what that means

515
00:26:57.599 --> 00:27:01.720
is we can't accelerate too quickly insteadtaneously, because that would

516
00:27:01.720 --> 00:27:05.200
be bad for the people going. In addition, we've got

517
00:27:05.240 --> 00:27:07.839
to get out of the atmosphere and the faster you

518
00:27:07.880 --> 00:27:11.079
travel through the Earth's air, the air pushers back at you,

519
00:27:11.160 --> 00:27:13.880
so it's really hard to speed up. And you can

520
00:27:13.880 --> 00:27:15.359
see this if you get a sheet of paper in

521
00:27:15.400 --> 00:27:17.279
your hand and try and push it through the airface

522
00:27:17.319 --> 00:27:19.519
onto the air. If you go gently, it's not too bad.

523
00:27:20.039 --> 00:27:21.839
The harder you push it, the more the paper will

524
00:27:21.880 --> 00:27:23.880
bend back against your hand as it's pushed back by

525
00:27:23.880 --> 00:27:26.680
the air resistance. So a big part of getting to

526
00:27:26.720 --> 00:27:29.599
space is actually getting out of the earth atmosphere. And

527
00:27:29.680 --> 00:27:32.599
the way we've solved all of these problems is to

528
00:27:32.680 --> 00:27:36.680
build really really really big rockets with multiple stages and

529
00:27:36.839 --> 00:27:40.640
use those to propel objects into space, and then when

530
00:27:40.640 --> 00:27:42.839
the first stage is dealt with, it falls away. You

531
00:27:42.839 --> 00:27:44.519
get rid of that mass and you get a smaller

532
00:27:44.519 --> 00:27:48.079
and smaller spacecraft. So when astronauts went to the Moon

533
00:27:48.079 --> 00:27:50.680
of the nineteen sixties, they had this enormous rocket called

534
00:27:50.720 --> 00:27:53.480
the Saturn five rocket. You can look at things of it.

535
00:27:53.920 --> 00:27:56.279
When I was a kid, we went to Florida and

536
00:27:56.319 --> 00:27:59.440
we went and I stood next to the Saturn five rocket.

537
00:27:59.440 --> 00:28:02.680
It too, and it's bonkersly big, much.

538
00:28:03.480 --> 00:28:06.039
Like it looks big untake. But when you're standing next

539
00:28:06.079 --> 00:28:09.240
to it, you go, oh, my gosh, it is very

540
00:28:09.359 --> 00:28:10.759
much bigger than you think it's going to be.

541
00:28:10.920 --> 00:28:13.279
Yeah, it's long enough that an Olympic sprinter would take

542
00:28:13.319 --> 00:28:15.480
about ten seconds to run the length of it. Something

543
00:28:15.559 --> 00:28:19.160
like that. Ridiculously big. So that is a giant firework

544
00:28:19.200 --> 00:28:22.160
that we built ten nationals to the room to the moon,

545
00:28:22.279 --> 00:28:26.640
and it launches it. The rocket engine goes off like firework,

546
00:28:26.720 --> 00:28:29.680
pushing them higher and higher into the sky, speeding up

547
00:28:29.720 --> 00:28:32.759
at a speed, at an acceleration that anything in the

548
00:28:32.759 --> 00:28:36.440
top could manage. So it's uncomfortable and you've been pushed

549
00:28:36.480 --> 00:28:39.759
back into your seats, but it's not so extreme. It

550
00:28:39.799 --> 00:28:43.039
makes you one well. And that big rocket is made

551
00:28:43.079 --> 00:28:45.359
of multiple parts. So when you get quite hoping in

552
00:28:45.400 --> 00:28:47.559
the atmosphere and all the fuel is used up in

553
00:28:47.559 --> 00:28:50.359
the first part, that falls away, and you've now got

554
00:28:50.359 --> 00:28:52.839
a smaller rocket that does the next burn and pushes

555
00:28:52.880 --> 00:28:56.079
you even faster and faster, and eventually you get out

556
00:28:56.079 --> 00:28:58.240
of the atmosphere. And that's good because you no longer

557
00:28:58.279 --> 00:29:01.839
have the wind resistance against you, and you can therefore

558
00:29:02.000 --> 00:29:04.240
use less energy to move around because you're not pushing

559
00:29:04.240 --> 00:29:06.359
against the wind. So once you're out of the atmosphere

560
00:29:06.400 --> 00:29:09.599
it gets easier. What does happen then is that the

561
00:29:09.680 --> 00:29:12.079
rocket will do one final boost to get you to

562
00:29:12.119 --> 00:29:14.680
a speed where you'll travel towards the Moon, and it

563
00:29:14.680 --> 00:29:16.960
will take you two or three days to get there,

564
00:29:17.400 --> 00:29:21.440
and you cost you then go into free fall, floating there,

565
00:29:21.480 --> 00:29:23.519
just cruising on. And this is a bit like when

566
00:29:23.519 --> 00:29:25.240
you've got up to speed on the highway and your

567
00:29:25.279 --> 00:29:27.960
car's just going along at the speed limit, minding it

568
00:29:29.000 --> 00:29:30.799
neutral and ninja just a bit on neutral, and you

569
00:29:30.880 --> 00:29:33.440
just cruise a lot. And at this point you've got

570
00:29:33.480 --> 00:29:36.440
a couple of days of the astronauts feeling weightless because

571
00:29:36.480 --> 00:29:39.119
they're moving at the same speed as a spacecraft around them,

572
00:29:39.440 --> 00:29:41.279
and they just courst along. And then when you get

573
00:29:41.319 --> 00:29:44.519
near to the Moon, you're going too quickly to orbit

574
00:29:44.559 --> 00:29:46.079
the Moon because you're going at the speed you need

575
00:29:46.119 --> 00:29:48.119
to do to get there. So you need to turn

576
00:29:48.160 --> 00:29:50.880
around and slow down again to slow down enough to

577
00:29:50.920 --> 00:29:53.400
get into orbit around the Moon. And so the rockets

578
00:29:53.400 --> 00:29:55.920
burn again, pushing you in the other direction, slowing you

579
00:29:56.000 --> 00:29:58.799
down until you're moving on an orbit around the Moon

580
00:29:58.839 --> 00:30:01.480
that kind of circul and maybe a few tens of

581
00:30:01.519 --> 00:30:04.519
kilometers above the Moon's surface. And he sit there for

582
00:30:04.519 --> 00:30:07.319
a while and check that everything's okay, because it's hard

583
00:30:07.359 --> 00:30:09.599
work and you want to make sure things are right.

584
00:30:10.319 --> 00:30:12.279
But then when the astronauts went to the Moon, the

585
00:30:12.319 --> 00:30:14.559
final part was that two of the astronauts on the

586
00:30:14.559 --> 00:30:18.200
mission climbed into this small landing module and the third

587
00:30:18.240 --> 00:30:21.039
one staid piloting the orbiter. They stayed above the Moon

588
00:30:21.039 --> 00:30:24.160
and didn't go down to the surface, but the landing module,

589
00:30:24.240 --> 00:30:27.400
separated from the orbitter, got nudged away and then used

590
00:30:27.400 --> 00:30:30.480
its own small little rockets to boost and slow down

591
00:30:30.519 --> 00:30:32.960
and boost and slow down until it touched down and

592
00:30:33.000 --> 00:30:36.200
landed safely at a specific point on the Moon, and

593
00:30:36.240 --> 00:30:38.240
the pilot had to watch up what they were doing.

594
00:30:38.240 --> 00:30:40.119
They were kind of looking out at the ground below

595
00:30:40.160 --> 00:30:42.440
to pick the best place to land. And with the

596
00:30:42.519 --> 00:30:45.160
very first landing, when Neil Armstrong and Buzz Aldering landed

597
00:30:45.200 --> 00:30:47.359
on the Moon, they kept going and kept going and

598
00:30:47.440 --> 00:30:49.240
nearly run out of fuel. They only had a few

599
00:30:49.240 --> 00:30:52.279
seconds left before they would have to abort and boost

600
00:30:52.359 --> 00:30:54.720
back up, because when you land on the Moon, you've

601
00:30:54.759 --> 00:30:56.960
got to get back. So the land on the Moon,

602
00:30:57.160 --> 00:30:59.799
they do all their fun things. They bounce around like kangaroos.

603
00:31:00.480 --> 00:31:02.720
But then to get back to Earth, they've got to

604
00:31:02.759 --> 00:31:05.640
get back in this small landing module which is probably

605
00:31:05.680 --> 00:31:07.599
not got much more room in it, to be honest

606
00:31:07.599 --> 00:31:11.160
in the interior of your car, strap themselves in and

607
00:31:11.200 --> 00:31:14.920
then the top of the module detaches, leaving the legs behind.

608
00:31:15.359 --> 00:31:17.880
The rocket pushes them back up so they can get

609
00:31:17.920 --> 00:31:21.759
into orbit around the Moon. They dock and reconnect with

610
00:31:21.880 --> 00:31:25.440
the parent spacecraft that the pilot was sad in waiting

611
00:31:25.519 --> 00:31:27.519
for a couple of days on their own. Then they

612
00:31:27.599 --> 00:31:29.440
turn on their rockets and they come back to the

613
00:31:29.480 --> 00:31:32.640
Earth send thing. They boost up up to a high speed,

614
00:31:33.079 --> 00:31:35.160
then their cruise along, floating there for a couple of

615
00:31:35.240 --> 00:31:37.920
days until they get near the Earth. Then they boost

616
00:31:37.920 --> 00:31:40.799
their rockets again to slow down, fall into the atmosphere

617
00:31:40.839 --> 00:31:44.279
and land again. So it's a big, long, dramatic journey.

618
00:31:44.799 --> 00:31:46.920
Now we've got better technology now so we can do

619
00:31:47.000 --> 00:31:50.279
it more effectively, and that's why NASA are hoping to

620
00:31:50.319 --> 00:31:52.200
send people back to the Moon in the next few

621
00:31:52.279 --> 00:31:55.599
years now. Everybody who went to the Moon so far,

622
00:31:56.079 --> 00:31:58.680
all twelve people who walked on the Moon where people

623
00:31:58.680 --> 00:32:00.559
who looked a bit like me and Andrew Fred. There

624
00:32:00.599 --> 00:32:04.519
were all the white men and that was it. And

625
00:32:05.000 --> 00:32:06.880
you know, these were all people who trained as test

626
00:32:06.920 --> 00:32:10.000
pilots and stuff like this. With the next people landing

627
00:32:10.000 --> 00:32:13.160
on the moon, they're going to be, you know, a

628
00:32:13.200 --> 00:32:15.759
wider variety of people. So the hope is that in

629
00:32:15.799 --> 00:32:17.920
a few years time we'll see the first woman walk

630
00:32:17.960 --> 00:32:20.720
on the moon and the person who isn't white to

631
00:32:20.799 --> 00:32:23.039
walk on the moon as well, And that'll be really

632
00:32:23.079 --> 00:32:25.359
good because it's important to know that this is something

633
00:32:25.400 --> 00:32:28.680
anybody can do. Everybody could learn to be an astronaut.

634
00:32:28.680 --> 00:32:31.799
It's very competitive and really hard. But if you only

635
00:32:31.839 --> 00:32:33.960
ever see people who look like Me and Andrew do it,

636
00:32:34.000 --> 00:32:35.880
you'll think they're the only kind of people who can.

637
00:32:36.400 --> 00:32:40.200
So it's really important to have everybody represented in this.

638
00:32:40.240 --> 00:32:42.799
And I think it's really exciting that in a few

639
00:32:42.880 --> 00:32:44.759
years time we want to just talk about men walking

640
00:32:44.839 --> 00:32:46.960
on the moon, but we'll talk about men and women

641
00:32:47.039 --> 00:32:49.480
walking on the moon. That's going to be really cool. Yes,

642
00:32:49.519 --> 00:32:49.799
it is.

643
00:32:50.279 --> 00:32:54.759
I grew up in the pioneering era of space flight

644
00:32:55.480 --> 00:32:58.160
and going to the Moon, and I was quite young

645
00:32:58.240 --> 00:33:01.359
when Neil Armstrong his foot on the surface and was

646
00:33:01.400 --> 00:33:04.000
followed by Buzz Alder, and I was so very lucky

647
00:33:04.000 --> 00:33:07.119
to meet buzz Aldron many many years later and I

648
00:33:07.240 --> 00:33:10.039
got to interview him for the Australian Broadcasting Corporation. That

649
00:33:10.160 --> 00:33:13.000
was probably one of the highlights of my career, to

650
00:33:13.039 --> 00:33:15.559
be honest, to meet someone so famous, one of the

651
00:33:15.599 --> 00:33:17.880
most famous people in the world because of what he did.

652
00:33:18.359 --> 00:33:20.599
But it's reached a point now where people are going

653
00:33:20.680 --> 00:33:23.359
up and down all the time into space and will

654
00:33:23.440 --> 00:33:26.440
never know their names because it's become so common. But

655
00:33:27.039 --> 00:33:29.480
as you say, with Artemis going back to the Moon

656
00:33:29.519 --> 00:33:32.200
and those people setting foot on the surface again, men

657
00:33:32.279 --> 00:33:38.160
and women of multiple races, they will again reignite that

658
00:33:38.279 --> 00:33:42.039
fame that goes with doing something so extraordinary. And Emily,

659
00:33:42.119 --> 00:33:45.880
I would imagine that in your lifetime it will reach

660
00:33:45.880 --> 00:33:48.880
a point where there will be people living on the Moon.

661
00:33:49.559 --> 00:33:54.000
I expect that will happen, might even happen in my lifetime,

662
00:33:54.039 --> 00:33:57.680
but certainly in yours it'll be very different, maybe even Mars. Emily,

663
00:33:59.200 --> 00:34:02.279
Thank you so the question, Thanks Sandy, always great to

664
00:34:02.319 --> 00:34:06.799
hear from our younger listeners. Johny, I'm going to make

665
00:34:06.799 --> 00:34:10.719
an executive decision and I'm going to Pigeonhole Fenton until

666
00:34:10.760 --> 00:34:14.280
next week because his question is two hours long, and

667
00:34:14.559 --> 00:34:17.119
I imagine the answer will be five times that, so

668
00:34:17.880 --> 00:34:19.840
I just don't think we can fit it in today.

669
00:34:20.159 --> 00:34:22.639
But it's a great question about the radiation of Jupiter.

670
00:34:22.760 --> 00:34:24.599
We will put that at the top of the tree

671
00:34:25.119 --> 00:34:28.079
for next week's Q and A episode. But thanks to

672
00:34:28.119 --> 00:34:30.440
everyone who contributed, and don't forget. If you've got questions

673
00:34:30.440 --> 00:34:33.920
for us, jump on our website space nuts podcast dot

674
00:34:33.960 --> 00:34:38.559
com and space nuts dot io to URLs and just

675
00:34:38.599 --> 00:34:41.440
click on that little AMA link at the top. That's

676
00:34:41.480 --> 00:34:43.840
where you send you text and audio questions. If you've

677
00:34:43.880 --> 00:34:46.840
got a device with a microphone, you're all set. Have

678
00:34:46.880 --> 00:34:48.480
a look around while you're there, and don't forget our

679
00:34:48.519 --> 00:34:53.519
social media very very active. The space nuts Facebook page

680
00:34:53.880 --> 00:34:56.360
is our official page, but we've got the space Nuts

681
00:34:56.480 --> 00:35:00.840
podcast group facebook page where people get together and chat

682
00:35:00.880 --> 00:35:04.119
and talk and compare photos and notes, and yeah, it's

683
00:35:04.239 --> 00:35:07.199
very very active. It's a great site. And thanks to

684
00:35:07.239 --> 00:35:10.039
our administrators who look after it for us because I

685
00:35:10.039 --> 00:35:12.719
haven't got time most of the time, except when i've

686
00:35:12.760 --> 00:35:17.920
got time and it's time to go. Thank you very much, Johnny.

687
00:35:18.039 --> 00:35:20.239
Always great fun. We'll catch you next week.

688
00:35:20.679 --> 00:35:22.239
That's your ladder. Thank you for having me.

689
00:35:22.719 --> 00:35:28.639
Johnny Horner, professor of astrophysics at the University of Southern Queensland,

690
00:35:29.840 --> 00:35:33.039
joining us while Fred is away. And we'll speak to

691
00:35:33.280 --> 00:35:36.119
Johnty again next week and to hear you in the studio.

692
00:35:37.039 --> 00:35:40.400
He was a wall because he's putting peeplates on his

693
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car so that he can go faster. And from me

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Andrew Dunkley, thanks for your company. Will catch you on

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the very next episode of Space Nuts. Bye byepauts to.

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The Space Nuts podcast, available at Apple Podcasts, Spotify, iHeartRadio,

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or your favorite podcast player. You can also stream on

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demand at bites dot com.

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This has been another quality podcast production from sites dot com.
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