Feb. 17, 2025

Alien Signals, Bone Density & Cosmic Disks: #496 - The Great Space Q&A Returns

Alien Signals, Bone Density & Cosmic Disks: #496 - The Great Space Q&A Returns

Space Nuts Episode 496: Life on Other Planets, Centrifugal Forces, and Bone Density in Space
Join Andrew Dunkley and Professor Jonti Horner in this thought-provoking Q&A edition of Space Nuts, where they tackle some of the most intriguing...

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Space Nuts Episode 496: Life on Other Planets, Centrifugal Forces, and Bone Density in Space
Join Andrew Dunkley and Professor Jonti Horner in this thought-provoking Q&A edition of Space Nuts, where they tackle some of the most intriguing questions from our listeners. From the possibility of detecting life on distant planets to the fascinating dynamics of centrifugal force, and the effects of zero gravity on bone density, this episode is brimming with scientific insights that will spark your curiosity about the universe.
Episode Highlights:
- Detecting Life on Distant Planets: Ron's compelling question leads the discussion on whether scientists in other solar systems could identify life on Earth using current technology, and vice versa. Jonti elaborates on the challenges and potential methods for detecting life beyond our planet.
- Spheres vs. Disks: Dean asks why celestial objects form as spheres while others appear as disks. Jonti explains the physical processes at play, including hydrostatic equilibrium and angular momentum, shedding light on the fascinating shapes of stars, planets, and galaxies.
- Bone Density in Space: Ann's insightful question about calcium loss in astronauts prompts a deep dive into the effects of microgravity on bone health. Jonti shares findings from recent studies and discusses the implications for long-term space missions.
- Centrifugal Force Explained: Aussie Dean's inquiry about the nature of centrifugal force and its measurement leads to a discussion on reference frames and how they relate to our understanding of gravity and motion on Earth.
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 detecting life on other planets
10:30 - Exploring the shapes of celestial objects
18:00 - Insights into bone density loss in space
26:45 - Understanding centrifugal force and reference frames
30:00 - Closing thoughts and listener engagement
✍️ Episode References
NASA's Studies on Bone Density
https://www.nasa.gov/spaceflight
Hydrostatic Equilibrium in Celestial Bodies
https://en.wikipedia.org/wiki/Hydrostatic_equilibrium
Centrifugal Force and Gravity
https://www.physicsclassroom.com/class/circles/Lesson-2/Centrifugal-Force

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

 

 

WEBVTT

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Hi there, Andrew Dunkley here, Thanks for joining us on

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a Q and A edition of Space Nuts, and coming up,

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we're going to answer a question from Ron. He wants

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to know if we could see a planet that sustains life,

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would we know it? And vice versa. If there was

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an alien race out there and they spotted Earth, would

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they know we are here? Good question. Dean is a

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bit confused about spheres versus discs. Why does it happen?

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Why aren't they all spheres or all discs? And has

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a brilliant question love this one about bone density in

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space and some of the problems that are associated with

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being in zero gravity for long periods of time, and

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Dean two, it's not the same. Dean is asking us

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about centrifugal force. We'll cover all that in this episode

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of Space.

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Nuts fifteen, Channel ten nine.

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Ignition Space Nuts Guy or three spaces hasn't actually bought it?

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Neils Good Here he is again.

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Professor John T. Horder, Professor of estrophysics at the University

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of Southern Queensland.

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Johnty, Hello, Hey, how are you going?

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I'm all right? A question without notice?

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Yes?

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Did you ever sort of have people review at school?

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Like John ty Horner said in the corner eating his

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Christmas pie, down came the comet that made Johnty vomit,

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and now he only is flies.

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Oh that's brilliant. That would have been far more pleasurable

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than marchall skill experience. It's probably not worth getting into

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too depressing a thing, but up until I got to

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Upper Clamento University, I had a horrendous, horrendous time at

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school because I was I grew up in a very

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working class area, lost social economic area with hugely high unemployment,

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neurly the minor strikes in the eighties, and I was

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an only child, so I'm not necessarily blessed with the

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best social aptitude particular that age. But I was smart

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enough to be very smart, but not smart enough to

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realize that there were the right way and the wrong

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way to go about that. So I had a horrible,

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horrible time for the twelve years at school. In terms

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of bully I was catastrophically bullied, but you know, it

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mainly who I am today, so I'm not going to

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complain too much about it. But yeah, it's a curse

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of having aspiration and the curse of being smart in

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an area where that wasn't a common thing. You know,

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a lot of empathy for the kids who went to

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school with because you're talking about an area where many

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of them didn't have any family members who were employed

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because of what was going on. There was a huge

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epidemic of men taking their own lives because of all

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the things that were going on. So it was a

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pretty rough time, a pretty rough place. But such as

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life unfortunately, you know.

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Yeah, yeah, I certainly had my share of bullying at school,

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and yeah, not often, wasn't an every day thing. It was,

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I suppose, looking back, reasonably rare. But it never sits well,

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it's it's a horrible thing.

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At least, he says. Nowadays, there is more being done

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to counter and more al wavers of it, because you know,

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the impression back when I was at school was he

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just needed to manna, which is an awful phrase, and

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everybody has to deal with it. It's a formative experience,

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and he just couldn't tell us. As long as you

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weren't getting naive to something it were, they weren't interested.

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I used to talk to my boys about it and

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ask them how they were going, and they always said, no,

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we never had any trouble, but then teachers would tell

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me otherwise, so they're obviously not keen to talk about it.

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But my middle son, who was always very tall through school,

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he was he tired above all the other kids. I

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think he was the second tallest kid in his year

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and in the school in general. And I said to

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him one day that you get bullied, and he went no,

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because he was big. He was a big kid, and

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no one, no one went near him. His height was

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actually a good defense mechanism. It's funny how it works out.

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But there's a lot about anthropology, I suppose when.

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You're talking about it. It's all interesting about the edges

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in which kids develop awareness of self and the edges

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at which they develop empathy and kindness and all those

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kind of things in a specific center rather than the

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general sense. It's really interesting.

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Yeah, it is, all right. Let's deal with some questions,

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and our first question comes from Ron. He said, if

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scientists in a distant solar system were searching for exoplanets

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using the same technology that we're using, and if they

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were to observe our planet, would they be able to

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tell with any degree of certainty that there was life

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here or Conversely, if we were to observe an exoplanet

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that's exactly like Earth, teeming with carbon based life and

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perhaps with an advanced civilization modifying their atmosphere, which we

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talked about in the last could we tell that there's

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life there? Thanks? Ron, great question, Ron, We've had questions

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like it before, but I just love this topic, so yeah,

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we'll do it again. And Johnty hasn't had to answer

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this one before, so I thought it'd be interesting to

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get his take on it.

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Well, it's a fabulous question, and I mean, the sad

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answer is we're not quite there yet. So if we

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were looking at the Solar System from around another star,

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depending on which method we use, we'd be able to

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find Jupterum, probably Saturn, but we'd have to observe for

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a very long time to measure the wobbles for them.

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So we need to observe the Sun for a decade

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or two to pick up DUP from Saturn. Everything else

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we wouldn't be able to find. Now, if we have

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something like tests the Transit eight Planet Service that'llite looking

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at our Solar system, there's a very small chance it

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might pick up the Earth, our venus but test typically

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it starts for twenty seven days. The Earth takes three

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hundred and sixty five days to around and would take

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over sixteen hours to transit, so the old of catching

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a transit a pretty much nil. So we're not there yet.

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We are getting better, and as we talked about in

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the other episode, we're getting to the point where we

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can find planets that are a bit bigger than the Earth,

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but on all bits that are comparable to the Earth.

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Around stars like the Sun. We can find planets smaller

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than the Earth around dim little red dwarf stars using

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the transit method, but that's partly because as planets are

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so close they're stars, they're going around really quickly. So

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the upshot of all that is, if we were orbiting

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another star looking back at the Solar System, I think

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we could only confidently detect one or two planets. The

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Earth would probably be the third planet that would be

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discovered as a technology got better, because it's the biggest

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of the terrestrial planets. But it would depend a little

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bit on your line of sight because the treasural planets

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are all slightly tilted to each other, So if you're

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going to find them through the transit method, the likelihood

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is only one of them will transit and the others won't.

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In the radial velossy method, you'd pick out Jupter and Saturn,

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but you'd struggle for anything else. Eventually you get there,

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but you'd need technology a bit better than ours. So

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we're not at the point of finding the planets yet,

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never mind finding the life on them. But that's like

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the next step in the journey. We've only had thirty

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years of the exoplanet ere we're only in the first

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few decades have been able to do this at all,

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and the progress we've made is ugly astonishing, and I

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think within the next decade or two will routinely start

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being able to find planets that are Earth sized on

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Earth like orbits and to start looking for evidence of

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life on them. But that is going to be the

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hardest observations we've ever to carry out in terms of

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detecting life like us, so it's a slightly different proposition.

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So finding any evidence of life is going to be challenging.

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So people often talk about biomarkers, which is this concept

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that there are certain things you could look for that

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will be indicative of life. And we've talked about the

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possible detection of phosphene and venus atmosphere before. We've talked

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about stuff like the chicken soup experiment the Viking land

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did on Mars in the nineteen seventies, where they dug

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up some soil and put some soup on it, and

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so if it gave off gases, because they can be life,

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they use of nutrients. When you're looking at planets arounder

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the stars, there is no guarantee that life on those

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planets would have followed the same evolitary pathways as life

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on Earth. So a lot of the very specific biomarkers

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people propose there best on our knowledge of life on

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Earth because it's the only planet we know does have life,

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and it's the only example of life we've got. One

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of the examples here is something called the red edge,

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which is when you look at the spectrum of light

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from a planet, if the planet has a lot of

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plants on board that are using chlorophyll, chlorophyll absorbs incredibly

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strongly in the red, so you might see a feature

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in the red that is the signature of chlorophyll, and

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that will be an indication of plant life. The problem is,

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and again I'm not a biologist, so there's probably more

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to this than I'm going to say. In my simple

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version is that chlorophyll is an incredibly efficient compound for

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allowing plants to utilize the light like the light from

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our suck. But there are many other compounds that could

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do a similar job for stars of different temperatures that

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are there for different colors, so they put out the

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bulk of their light at slightly different wavelengths, And there's

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no guarantee that life on another planet would use chlorophyll,

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especially if that star was significantly different to the Sun,

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So the specific bymarker of the red edge from chlorophyll

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wouldn't work very well. Necessarily, it wouldn't be guaranteed to work,

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especially because it's also mimicked by the spectrum of olivine,

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which is a very common mineral, has a very similar appearance.

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But looking more generally for that kind of absorption feature

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in the spectrum that you can't explain any other way

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is one of the size people have looked for. So

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it's not so much case of looking for a specific thing,

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but rather for looking for something that is out of place,

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trying to explain it, and finding that the only explanation

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left is life. You're looking for something out of balance.

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So another good example is on Earth, we have oxygen,

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we have methane. Now, there's a lot of oxygen in

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the atmosphere, but that doesn't necessarily mean life, because there

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are chemical processes that can produce oxygen without life being involved.

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Similarly with a lot of methane in the atmosphere. And

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methane is a natural product of animal life. I my

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dog line next to me has been quite happily producing

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methae through the podcast because we've fed at some broccoli

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I think in a puppy food last night. So methane

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is produced by life, but there are also lots of

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natural ways it can produce. And you know, there's huge

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amounts of methane in the atmospheres of Urinus and Neptune,

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for example. So finding oxygen or finding methane doesn't necessarily

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mean life. There's a lot of other explanations, but the

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oddity with Earth is that we've got oxygen and methen together. Now,

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when you put oxygen and methne together, they react with

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each other a lot, and they react until all of

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one of them is gone. So the methane in this

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atmosphere has a really short residence time of only a

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century or a few centuries I think four hundred year

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before it's all gone. So you look at the Earth

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and it's got oxygen and methen together, which means something

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has to be producing new methane to replace the methen

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that's lost. Now, even that doesn't mean it's life, because

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volcanoes perished me fed. So what you then have to

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do is say, well, this is interesting. It could be life,

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it could be something else. Let's measure the methane over time,

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and if it's volcanoes, you'll get the methane falling off

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and a random time of volcano ups and there's a

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spike of methane and then it falls off again, and

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a random time later you get another spike. But when

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you look at methane in the Earth's atmosphere, it varies

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with the seasons. Volcanoes don't do that, so therefore that's

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an indication of life. So it's looking for that oddity

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that's out of place. There are a couple of things

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that would give away arguably technologically developed life, which doesn't

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necessarily mean intelligent life, as we're seeing in the political sphere,

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at the minute, but technologically developed life. One of them

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is chlorophylor of carbons, So the things that we were

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putting up into the atmosphere that devastated the layer. Yeah,

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we only know of those being produced by technology if

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there is no natural process that seems to produce them.

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Another is radio broadcasts. So any intelligent aliens within about

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eighty light years of us ninety light years of us

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now would see our broadcast. Now. The exact date of

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the first broadcast that we sent out that was strong

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enough to be detected from around the stars depends w

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you talked. It could have been the Berlin Olympics in

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nineteen thirty six, I think, or the coronation of Queen

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Elizabeth in nineteen fifty two. I think with it it was,

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and they usually held has been the first big broadcast

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that would have been detectable on an interstellar distance. What

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that means is that within a certain distance of the

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Earth there is a sphere where if there are intelligent

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aliens with radio telescopes, they could be watching neighbors and

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we could well get a broadcast back at some point

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saying please stop. You know, we're a bit like toddlers

248
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at the minute in a room screaming into the void,

249
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and that sound is good further and further away from

250
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as a time goes on. Now that's the motivation for

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things like the Cechrectra threasurial intelligence, which is helping fund

252
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the wonderful radiotails go down to paths through the Breakthrough

253
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Listen project. The challenge there is that we are already

254
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starting to become more quiet, well like the baby becoming

255
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a totaler and moderating itself. And the reason for that

256
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is costs. If you were broadcasting in all directions all

257
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the time, you've got to put a lot of energy

258
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in and most of that energy is wasted, so only

259
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a twin a little bit of that is going to

260
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get to your receivers. It's much more efficient to send

261
00:13:33.559 --> 00:13:36.399
your data, like we're talking at the minute, through the

262
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end the end, through wires or through point to point stuff.

263
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So the silent satellites are a bit like this. They're

264
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broadcasting down Therefore venal little is going back out into space,

265
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and anything connecting to them points at the satellite and

266
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beams directly to it. So it's much more energy efficient.

267
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And there are some arguments that the Earth could well

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be radio silent again from the point of view of

269
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aliens listening in within just a few decades, so there'd

270
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only be a short window. And then you've got this

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shell of broadcasts moving outwards with a void behind it,

272
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and unless you tune in when that shell's passing past,

273
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you'd never hear us. But in that sense, if we

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were looking at the Solar System with our biggish radio telescopes,

275
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we'd probably just about be able to pick up the

276
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unusual radio activity if we were at the right radio

277
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we were at the right distance, but it would still

278
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be challenging for us. I think we do have the

279
00:14:26.840 --> 00:14:30.440
capacity for that, but it would be hard. So in

280
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that sense, if there were aliens around, I don't know.

281
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Approxima centaury B, another of the many many planets that

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has been argued has been the most earth like ever discovered,

283
00:14:40.000 --> 00:14:42.720
and made me hungry. If there was a planet there,

284
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if there were aliens on it, and there were broadcasting

285
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alien neighbors, we'd be able to tune it.

286
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Wouldn't that be interesting? The answer to Ron's question is no,

287
00:14:53.200 --> 00:14:57.120
not yet. We're just not quite there. The time may

288
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well come, but again it's nearly in a hast.

289
00:14:59.639 --> 00:15:02.879
Exter, isn't it you? Absolutely? I said, you don't know

290
00:15:03.000 --> 00:15:05.080
what a needlest and you've never seen a half start befire?

291
00:15:05.159 --> 00:15:09.960
Yeah, exactly, Yes, thank you Ron, great question, lovely to

292
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hear from you. Okay, we take Space Nuts and our

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next question comes from Dean high Space Nuts.

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I'm Dean from Washington, d C. In the United States.

295
00:15:26.399 --> 00:15:30.000
I originally started listening to the show and okay, anyways,

296
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I was wondering why under gravity do some things form

297
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as discs and others as spheres. You know, we're stars

298
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and planets are spheres, but some galaxies in our soul

299
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systems a disc. But then also planet can have discs

300
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around them. All very anyways, thanks, keep up your.

301
00:15:48.600 --> 00:15:51.799
Very thank you Dean. I never would have even thought

302
00:15:51.840 --> 00:15:54.600
of that question, and it's a great question. But yeah,

303
00:15:54.840 --> 00:15:58.000
he's right. You've got spheres and you've got discs, you've

304
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got mixtures of spheres and discs, You've got all sorts

305
00:16:01.559 --> 00:16:02.399
of combinations.

306
00:16:03.919 --> 00:16:08.480
Why is it so it's all down to different physical

307
00:16:08.519 --> 00:16:10.919
presses going on? So it's fabulous question. And we run

308
00:16:10.960 --> 00:16:14.399
across this when we're teaching astro, when we're studying it

309
00:16:14.559 --> 00:16:17.960
quite a lot, and there are things that happen in

310
00:16:18.080 --> 00:16:22.840
slightly different situations. So if you've got material falling inwards

311
00:16:22.960 --> 00:16:27.559
under gravity, it will keep falling inwards until either it's

312
00:16:27.639 --> 00:16:29.480
moving around on an orbit it swings back out. But

313
00:16:29.559 --> 00:16:31.759
let's assume it's falling into an object that is going

314
00:16:31.840 --> 00:16:35.639
to become a solid or gasious subject that therefore has

315
00:16:35.679 --> 00:16:37.679
some way of stopping that material, so it slows down

316
00:16:37.720 --> 00:16:40.879
and becomes part of that object. You then have a

317
00:16:41.000 --> 00:16:44.200
balance between gravity trying to pull you inwards and the

318
00:16:44.279 --> 00:16:47.879
physical strength of the material pushing outwards. If you've got

319
00:16:47.879 --> 00:16:51.279
a solid object, if you've got a gasio subject, the

320
00:16:51.360 --> 00:16:53.080
gas can keep going in, but then you build up

321
00:16:53.120 --> 00:16:55.679
pressure of the pressure holds things up. You might have

322
00:16:56.279 --> 00:17:00.320
energy being released that also holds it up, so that

323
00:17:00.559 --> 00:17:04.599
then pushes outwards in all directions. I'll talk about solid

324
00:17:04.640 --> 00:17:08.359
objects first. This ties into a little bit towards the

325
00:17:08.400 --> 00:17:12.240
definition of a planet. There is a concept called hydrostatic equilibrium,

326
00:17:13.759 --> 00:17:17.799
which is basically the shape that something that has no

327
00:17:18.039 --> 00:17:22.640
strength will finish up in. Once everything's moved around, you

328
00:17:22.720 --> 00:17:25.519
say that it's in hydrostatic equilibrium. It's the lowest kind

329
00:17:25.519 --> 00:17:30.440
of energy state. So if you got outside the Earth's atmosphere,

330
00:17:31.039 --> 00:17:33.200
or rather you go away from the gravity of the Earth,

331
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putting things down, and you can have droplets suspended. A

332
00:17:37.079 --> 00:17:39.559
drop of water that is not moving at all will bispherical.

333
00:17:39.599 --> 00:17:43.119
It's held in by surface tension in that case holds

334
00:17:43.119 --> 00:17:45.279
it together, but it will be a sphere. If you

335
00:17:45.480 --> 00:17:49.079
rotate it, it will gradually become more elongated than a blade,

336
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and it become what we call an ablate spheroid, which

337
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is what the Earth is. The Earth is wider at

338
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the equator than the poles because of the rotation, and

339
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the rotation is essentially applying a slight out force. That

340
00:18:01.720 --> 00:18:03.920
means the net force pulling in is weaker at the

341
00:18:03.960 --> 00:18:06.359
equator of the poles, and so you stretch out of it.

342
00:18:06.480 --> 00:18:10.599
That's kind of how I visualize it. Yep. If you

343
00:18:10.759 --> 00:18:14.599
are smaller than a certain size, your material strength is

344
00:18:14.680 --> 00:18:18.200
strong enough to prevent things moving around and flowing, so

345
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you don't become spherical. You don't get that hydrostatic equilibrium.

346
00:18:22.599 --> 00:18:24.759
So if you look at the moons of the planets,

347
00:18:25.920 --> 00:18:29.519
the smallest one that I think is in hydrostatic equilibrium

348
00:18:29.599 --> 00:18:33.119
is possibly mimas at Saturn, about four hundred kilmeters across.

349
00:18:33.119 --> 00:18:34.680
It might be one of the other Saturnian modes, but

350
00:18:34.720 --> 00:18:37.920
I think it's Mimus because that's about the size where

351
00:18:37.960 --> 00:18:40.839
you've got enough mass that the gravitational pull is strong

352
00:18:41.000 --> 00:18:43.920
enough that that can overcome the physical strength of the

353
00:18:43.960 --> 00:18:46.799
material where the object's forming have cause it to then

354
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move and flow, and you end up then getting nearly

355
00:18:50.839 --> 00:18:53.160
a sphere because that's the lowest energy solution. That's your

356
00:18:53.240 --> 00:18:58.720
hydrostatic equilibrium. If you had it being wider than that,

357
00:18:59.160 --> 00:19:01.720
more like a look like an ice hockey puck maybe,

358
00:19:02.359 --> 00:19:05.640
but the material can flow. You've got more mass pushing

359
00:19:05.720 --> 00:19:08.279
down in the horizontal plane, so things try and squeeze

360
00:19:08.279 --> 00:19:10.480
in here and they'll be pushed out that way until

361
00:19:10.519 --> 00:19:12.720
it bounces out, so you'd end up flowing until you've

362
00:19:12.759 --> 00:19:16.240
got that kind of spherical shape. Yeah, your ice hockey puck,

363
00:19:16.279 --> 00:19:18.720
though small enough that its material shredth winds, so it

364
00:19:18.839 --> 00:19:22.720
stays at elongated shape. So that's kind of the lower

365
00:19:22.839 --> 00:19:25.160
end of when people start talking about the definition of

366
00:19:25.200 --> 00:19:28.079
a planet is it has to be in hydrostaphic equilibrium.

367
00:19:28.240 --> 00:19:30.880
Doesn't mean it's spherical, it just means it's in that

368
00:19:30.960 --> 00:19:33.160
lowest energy thing. So if it's rotating quickly. It can

369
00:19:33.240 --> 00:19:36.119
be a kind of oblate spheroid. You get a similar

370
00:19:36.160 --> 00:19:38.640
thing with stars. So you've got all this gas collapsing

371
00:19:38.720 --> 00:19:42.119
in friction, stopping it just opening and escaping again. So

372
00:19:42.200 --> 00:19:46.359
you've got an object. That object has gravity pulling inwards

373
00:19:46.400 --> 00:19:48.759
and it's got a restoring force pushing outwards. In the

374
00:19:48.799 --> 00:19:50.759
case of a cell like the Sun, that's the radiation

375
00:19:50.880 --> 00:19:52.640
pressure from all the nuclear fusion going on.

376
00:19:52.680 --> 00:19:53.160
In its cot.

377
00:19:54.000 --> 00:19:57.119
Now the Sun's rotating, albeit once every thirty odd days,

378
00:19:57.920 --> 00:20:00.160
but it is in something that is close to that

379
00:20:00.279 --> 00:20:03.079
hydrostaphic equilibrium. So if you put a load of mass

380
00:20:03.160 --> 00:20:05.839
on the Sun's equator, that would squish in and the

381
00:20:05.920 --> 00:20:07.640
poles would push out until you got back to that

382
00:20:07.799 --> 00:20:11.799
kind of shape. So that's a physical kind of object.

383
00:20:12.279 --> 00:20:15.599
That's why you get them going to be spheres or

384
00:20:16.119 --> 00:20:19.440
nearly spheres. It's that concept of hygrostatic equilibrium, and it's

385
00:20:19.519 --> 00:20:21.559
due to the balance of the force pulling in woods

386
00:20:21.559 --> 00:20:25.759
and the force pushing outwards, radiation pressure of stars, material strength,

387
00:20:25.880 --> 00:20:30.079
material physics going on. For solid objects, with disks, you

388
00:20:30.240 --> 00:20:33.319
don't have the same things going on. So what you've

389
00:20:33.359 --> 00:20:35.559
got is you've got a rotating cloud of gas and

390
00:20:35.680 --> 00:20:39.599
dust that isn't really strong enough told itself up, but

391
00:20:39.720 --> 00:20:43.759
it's rotating quickly under gravity. Now you've got the conservation

392
00:20:43.839 --> 00:20:46.160
of angular momentum going on, so things near the middle

393
00:20:46.240 --> 00:20:49.079
go quicker than things near the outside, and there is

394
00:20:49.119 --> 00:20:51.920
a tendency for things to clapse down in a disc

395
00:20:52.039 --> 00:20:54.160
above the plane of the equator of the thing they're

396
00:20:54.240 --> 00:20:56.960
orbening around. That is due to the conservation of that

397
00:20:57.000 --> 00:21:00.440
angular momentum, but it's also due to the motion things through.

398
00:21:00.440 --> 00:21:03.440
You've got all sorts of things coming in. The analogy

399
00:21:03.519 --> 00:21:06.920
often is when I'm giving public talks. Here involves fittis

400
00:21:07.000 --> 00:21:09.240
that is different, so it's not a perfect analogy, but

401
00:21:09.279 --> 00:21:10.680
it gives you a kind of idea what's going on

402
00:21:10.759 --> 00:21:13.720
with spinning material, And it's if you've ever seen somebody

403
00:21:13.720 --> 00:21:16.920
who's a show off making pizza bases. They get a

404
00:21:17.039 --> 00:21:19.119
ball of very elastic dough and then they spin it

405
00:21:19.160 --> 00:21:21.079
around very quickly and whirl it over their head, and

406
00:21:21.119 --> 00:21:24.640
it flattens out into a big pancake as a result

407
00:21:24.680 --> 00:21:26.880
of the conservation of the annual momentum there, it flattens

408
00:21:26.920 --> 00:21:29.119
out into the pizza bair shape. And if I tried

409
00:21:29.119 --> 00:21:30.759
it it'd either stick to the ceiling or hit me

410
00:21:30.839 --> 00:21:33.960
on the head. It wouldn't go very well. It's a

411
00:21:34.079 --> 00:21:38.119
slightly similar thing with the distant material around planets and stars.

412
00:21:38.160 --> 00:21:42.160
Now what's happening is you've got material collapsing into the

413
00:21:42.200 --> 00:21:45.359
star under gravity, forming the disc around it because there

414
00:21:45.440 --> 00:21:48.200
is a bit of rotation with that rotation. As you

415
00:21:48.319 --> 00:21:50.519
spin in and you get to a smaller and smaller distance,

416
00:21:50.559 --> 00:21:53.559
you move faster and faster and faster. And that's why

417
00:21:53.640 --> 00:21:56.079
a gas cloud rotating every few million years gives you

418
00:21:56.160 --> 00:21:59.720
star rotating every few days or every few hours. It's

419
00:21:59.759 --> 00:22:01.519
like the ballerina bringing their arms in as they do

420
00:22:01.599 --> 00:22:04.400
a spin. There spin quicker and quicker. But that also

421
00:22:04.759 --> 00:22:07.279
tends to lead to things collapsing into the plane because

422
00:22:07.319 --> 00:22:09.759
that's a bit again like the hydro staff keeper whatever

423
00:22:09.839 --> 00:22:12.599
in example, that's kind of the lowest energy solution. You're

424
00:22:12.720 --> 00:22:16.400
rotating around the given rotation axis, you will collapse into

425
00:22:16.440 --> 00:22:19.880
a disc in that plane. Material that's coming in above

426
00:22:19.960 --> 00:22:23.319
that disc can just carry on orbiting normally, but if

427
00:22:23.359 --> 00:22:25.640
there's more material in the disc, there will be friction

428
00:22:25.759 --> 00:22:27.920
and it will get damped down and help to collapse

429
00:22:27.960 --> 00:22:33.599
down into there. But if the bulk is rotating with

430
00:22:34.359 --> 00:22:37.240
the same rotation access, anything falling in at high handles

431
00:22:37.240 --> 00:22:40.599
will probably just fall in and blockstraight onto the stars.

432
00:22:40.640 --> 00:22:44.000
It's rotating that way, but it's coming in here essentially. Yeah,

433
00:22:44.039 --> 00:22:46.599
I appreciate that description was really useful for the people

434
00:22:46.640 --> 00:22:48.599
who were only listening because I can't see me waving.

435
00:22:48.640 --> 00:22:51.359
My flappy hands are out. But if you're coming in

436
00:22:51.480 --> 00:22:54.200
from near the poles, the little bit of rotation around

437
00:22:54.319 --> 00:22:57.119
isn't helping again, so you coming in directly towards the target.

438
00:22:57.680 --> 00:22:59.200
If you're coming in from the poles and you're going

439
00:22:59.240 --> 00:23:01.359
to hit onto the day, you'll be passing through all

440
00:23:01.400 --> 00:23:04.000
that material and that will damp you down a little bit,

441
00:23:04.160 --> 00:23:07.400
so more inclined things will gradually get damp down. To

442
00:23:07.480 --> 00:23:10.160
add to the disc the discs we get there for

443
00:23:10.279 --> 00:23:13.440
around protest stars, a material that's falling in the rotation

444
00:23:13.640 --> 00:23:16.720
spinning it up. You get a disc around that protest

445
00:23:16.799 --> 00:23:19.079
star that this will be a bit fled, It will

446
00:23:19.119 --> 00:23:21.079
have a bit of height mixes, a lot of dynamics

447
00:23:21.160 --> 00:23:24.680
and stirring and things like that going on. If you

448
00:23:24.759 --> 00:23:27.240
could have a big enough region around it, you probably

449
00:23:27.319 --> 00:23:30.000
end up seeing a disc would eventually flare out and

450
00:23:30.079 --> 00:23:32.680
clickly comes a background, but you'd have almost cleared lobes

451
00:23:32.720 --> 00:23:35.240
above and below the star, and that's kind of what

452
00:23:35.279 --> 00:23:37.720
we see with our small body population in the Solar System.

453
00:23:37.720 --> 00:23:41.680
As you go from the planets and the edge of Kooperbalt,

454
00:23:41.799 --> 00:23:45.000
going further outwards, you gradually come out towards the domain

455
00:23:45.039 --> 00:23:46.799
of the art cloud, and when you're far enough from

456
00:23:46.839 --> 00:23:49.559
the Sun, things get stirred up by passing stars and

457
00:23:49.640 --> 00:23:51.880
get put back into a sphere because their tilts are

458
00:23:51.920 --> 00:23:54.839
all random housed. So you've got a disc near the Sun,

459
00:23:54.880 --> 00:23:57.480
and that's because the Sun's gravity is dominating the angual

460
00:23:57.519 --> 00:24:01.440
momentum dominating. When you're very far from the Sun, you're

461
00:24:01.519 --> 00:24:03.640
only loosely hell to the Sun, so nudge of from

462
00:24:03.680 --> 00:24:07.079
passing stars can change your direction quite significantly. And over

463
00:24:07.160 --> 00:24:09.920
the four billion years since the cell system formed, that

464
00:24:10.119 --> 00:24:12.359
material that was flung out into the out cloud in

465
00:24:12.400 --> 00:24:14.200
a disc because it was flung out from a disc,

466
00:24:14.839 --> 00:24:17.079
has been smeared around, so we now get as very

467
00:24:17.160 --> 00:24:20.480
coliche cloud around the Sun. But when you're close enough

468
00:24:20.519 --> 00:24:22.519
to the Sun for the Sun to dominate, you'd have

469
00:24:22.680 --> 00:24:25.359
voids that are fairly empty above and below the plane

470
00:24:25.720 --> 00:24:29.319
and a disc blowed out. So it's all complex and

471
00:24:29.400 --> 00:24:32.359
it's a couple of different bits of physics interacting essentially.

472
00:24:32.920 --> 00:24:36.279
Yeah, well, now I'd never wondered about it, and I'm

473
00:24:36.319 --> 00:24:42.319
glad Dane asked the question because it really is interesting science.

474
00:24:43.319 --> 00:24:48.960
Hydrostatic equal equally librial lime.

475
00:24:49.440 --> 00:24:51.359
It's the really good example of how sice works and

476
00:24:51.440 --> 00:24:54.160
how we do it actually, because that's exactly the scientific process.

477
00:24:54.240 --> 00:24:56.880
You see something, you go why is that? And Saturn's

478
00:24:56.880 --> 00:24:58.519
a great example. You look at sat and then it's

479
00:24:58.559 --> 00:25:01.640
a oblet's fair bit of an elongated blobby thing, but

480
00:25:01.680 --> 00:25:05.000
it's nearly spherical, rarely first order, and yet it's got

481
00:25:05.000 --> 00:25:06.759
a disc of material around it. Why is it? The

482
00:25:06.799 --> 00:25:09.799
discal's all block, you know. And so that's what leads

483
00:25:09.880 --> 00:25:12.079
us down that journey discovery to figure all this stuff out.

484
00:25:12.799 --> 00:25:14.960
So that's just how science works. And it's very fun,

485
00:25:16.000 --> 00:25:16.640
brilliant question.

486
00:25:16.799 --> 00:25:19.920
Thank you, Dane, lovely to hear from you. This is

487
00:25:20.000 --> 00:25:23.200
Space Nuts with Andrew Duckley and Johnty Horner.

488
00:25:28.920 --> 00:25:29.839
Space Nuts.

489
00:25:30.720 --> 00:25:34.400
Our next question, I really love. This one comes from

490
00:25:34.599 --> 00:25:38.519
an in Bellevue, Washington. I have a question about calcium

491
00:25:38.599 --> 00:25:43.160
and astronauts on Earth. Estrogen helps prevent calcium loss from bones.

492
00:25:43.960 --> 00:25:51.200
Do pre menopausal astronauts lose less bone or regain bone

493
00:25:51.319 --> 00:25:59.279
faster than mail or postmenopausal astronauts. Does hormone replacement therapy

494
00:25:59.519 --> 00:26:04.880
help minopausal astronauts regain bone. It's a really great question,

495
00:26:05.920 --> 00:26:08.839
and says thanks for the interesting podcast. Appreciate that, and

496
00:26:09.039 --> 00:26:13.880
thanks for the interesting question. I know this isn't your area,

497
00:26:13.960 --> 00:26:15.279
but I know you've done your homework.

498
00:26:16.160 --> 00:26:18.359
Yeah, I don't a little bit reading. It's a fascinating question,

499
00:26:18.440 --> 00:26:20.880
and it's a really important question to ask because there's

500
00:26:20.880 --> 00:26:24.319
a lot of investigations into the impact of being in

501
00:26:24.440 --> 00:26:27.079
space that are going on, particularly given that there's a

502
00:26:27.160 --> 00:26:31.160
future where people aspire to travel to Mars and live there,

503
00:26:31.279 --> 00:26:34.519
or have you know, space sessions where people with full

504
00:26:34.559 --> 00:26:38.160
time go colonize the asteroids, things like that. It's not

505
00:26:38.480 --> 00:26:40.759
my area of expertise by any means. I'm not a

506
00:26:40.799 --> 00:26:45.079
biologist or a biomechanists, but it is something people are

507
00:26:45.200 --> 00:26:49.160
starting to do research into. I haven't been able to

508
00:26:49.200 --> 00:26:52.680
find anything about the difference between pre and post menopause,

509
00:26:52.839 --> 00:26:56.839
or about estrogen supplements and things like that. That's a

510
00:26:56.920 --> 00:26:59.599
really interesting question, and it's almost possibly the kind of

511
00:26:59.640 --> 00:27:02.240
thing where you could find someone leading that kind of

512
00:27:02.279 --> 00:27:04.079
research and try and get involved if you want to.

513
00:27:04.079 --> 00:27:05.519
But I did do a bit of digging around. I

514
00:27:05.599 --> 00:27:09.680
found there is a paper that was published. I found

515
00:27:09.720 --> 00:27:12.400
it on pub meed that was published a few years

516
00:27:12.440 --> 00:27:15.480
ago in twenty fourteen and titled Men and Women in

517
00:27:15.559 --> 00:27:19.039
Space Bone Loss and Kidney stone Risk after among the

518
00:27:19.079 --> 00:27:24.000
Oration space Flight, which is a slightly intimidating title, but

519
00:27:24.359 --> 00:27:28.359
they not there that. Finally, at that stage there had

520
00:27:28.440 --> 00:27:32.799
been enough people who identified as male and identified as

521
00:27:32.880 --> 00:27:35.000
female that had spent a long time in space that

522
00:27:35.119 --> 00:27:38.400
you could start doing a quantitative comparison. They had in

523
00:27:38.480 --> 00:27:41.279
their sample thirty three men and nine women who had

524
00:27:41.279 --> 00:27:44.799
spent long the Oursan missions on the space station, and

525
00:27:45.759 --> 00:27:49.680
their bodies had been studied when they got back. Essentially,

526
00:27:49.759 --> 00:27:53.039
so I think that bone mineral density was evaluated before

527
00:27:53.079 --> 00:27:55.759
and after the flight and stuff like that, and they

528
00:27:55.799 --> 00:27:58.200
also looked at blood and urine to look at kidney function.

529
00:27:58.880 --> 00:28:01.799
The missions were fifty days to two hundred and fifteen

530
00:28:01.920 --> 00:28:06.640
days flown in this millennium, so twenty twenty twelve, what

531
00:28:06.799 --> 00:28:09.680
they found was the following alreadly out explicitly. They said

532
00:28:09.680 --> 00:28:12.279
the bondance to response to spaceflight was the same for

533
00:28:12.400 --> 00:28:15.240
men and women in both exercise groups, so no difference

534
00:28:16.480 --> 00:28:18.720
bond dens to response to flight was the same for

535
00:28:18.799 --> 00:28:22.480
men and women, and the typical decrease in bone mineral density,

536
00:28:23.200 --> 00:28:26.119
whole body and regional after flight was not observed for

537
00:28:26.240 --> 00:28:29.680
either sex for people who were using the advanced resistance devices,

538
00:28:29.759 --> 00:28:33.079
so they were able to recover equally well. So the

539
00:28:33.160 --> 00:28:35.599
fundamental comment there have as a final sentence of their

540
00:28:35.640 --> 00:28:38.559
abstract is the responses of men and women to spaceflight

541
00:28:39.279 --> 00:28:42.279
with respect to measures of bone health were not different,

542
00:28:43.519 --> 00:28:48.599
which is really interesting. It doesn't entirely talk about the

543
00:28:48.640 --> 00:28:50.759
importance of the hormones, but I guess the fact that

544
00:28:52.519 --> 00:28:56.960
women who were pre menopause and men experienced their bond

545
00:28:57.039 --> 00:29:01.039
density degradation at the same rate suggests that the elevated

546
00:29:01.599 --> 00:29:04.359
levels of estrogen in the women did not prevent that

547
00:29:04.519 --> 00:29:07.559
bondensity loss. Doesn't say anything about the speed at which

548
00:29:07.599 --> 00:29:10.640
the bond icity was recovered when they were back, so

549
00:29:10.799 --> 00:29:13.599
I can't really comment on that, but it reminded me

550
00:29:14.279 --> 00:29:17.240
more widely of a the risks of space flat but

551
00:29:17.359 --> 00:29:19.720
also the amount that we don't know, and the importance

552
00:29:19.759 --> 00:29:23.440
of getting people with different expertises involved, but also the

553
00:29:23.559 --> 00:29:29.400
importance of doctors and medical researchers studying women as well

554
00:29:29.400 --> 00:29:30.839
as men. And I know from a number of my

555
00:29:30.960 --> 00:29:33.680
female friends that they feel very much that a lot

556
00:29:33.720 --> 00:29:37.400
of medications, a lot of treatments assume that the male

557
00:29:37.440 --> 00:29:39.480
body is the normal one, and studies have not been

558
00:29:39.559 --> 00:29:42.559
carried out to such a great extent on the different

559
00:29:42.680 --> 00:29:45.640
impact of that same medication on the female body. True,

560
00:29:46.039 --> 00:29:48.759
and I've also heard of problems where male doctors have

561
00:29:48.880 --> 00:29:51.400
not been as well educated in female problems as they

562
00:29:51.440 --> 00:29:53.799
should have been in giving fairly rubbish responses. So, you know,

563
00:29:54.240 --> 00:29:56.960
acknowledging those biases and acknowledging that I'm in a very

564
00:29:57.000 --> 00:30:01.079
privileged situation, but we need more research into this. NASA

565
00:30:01.200 --> 00:30:03.839
has on its website a segment here talking about the

566
00:30:04.000 --> 00:30:08.160
degree of impact on bond density. So their segment is

567
00:30:08.240 --> 00:30:10.759
astronauts can lose up to one to two percent of

568
00:30:10.799 --> 00:30:13.920
bond density per month in the hip and the spine.

569
00:30:15.200 --> 00:30:18.240
That compares to zero point five to one percent per

570
00:30:18.359 --> 00:30:21.920
year in postmenopausal women and much older men on Earth. So,

571
00:30:22.039 --> 00:30:24.599
in other words, the bone loss that you're getting while

572
00:30:24.640 --> 00:30:29.279
you're in microgravity and space is around twice as significant

573
00:30:29.480 --> 00:30:32.039
as that that you experienced post menopause for women or

574
00:30:32.200 --> 00:30:36.119
when you become significantly older for men, and that they

575
00:30:36.200 --> 00:30:38.279
say this rappid bond loss can place crew members at

576
00:30:38.359 --> 00:30:41.119
risk for both fracturing and risk of elions osioporosis as

577
00:30:41.119 --> 00:30:44.880
a result of the space flag. There's another study which

578
00:30:44.920 --> 00:30:48.519
I just stumbled across, looking on this female astronauts impact

579
00:30:48.599 --> 00:30:51.880
of space radiation on menopause. This came out a bit

580
00:30:51.960 --> 00:30:54.720
more recently in Atal twenty twenty two, and it shows

581
00:30:54.799 --> 00:30:56.759
people are starting to think about this. So this is

582
00:30:57.400 --> 00:30:59.799
a study that is looking at the impacts of the

583
00:31:00.039 --> 00:31:03.680
radiation environment that you experience in space on what they

584
00:31:03.759 --> 00:31:06.119
call the avarian reserve, so the number of viable eggs

585
00:31:06.160 --> 00:31:09.319
that a woman has. And so the statement that really

586
00:31:09.400 --> 00:31:12.039
made my head hurt here is that data suggests that

587
00:31:12.200 --> 00:31:15.920
a typical Mars mission may reduce a woman's avarian reserve

588
00:31:15.960 --> 00:31:19.680
by about fifty percent. This would have consequences to a

589
00:31:19.720 --> 00:31:23.640
woman's reproductive capacity and most significantly decreases a time metaval

590
00:31:23.759 --> 00:31:27.960
to her menopaus. So it all reminds me it's slightly

591
00:31:28.039 --> 00:31:31.039
off topic, but This was prompted by this question. I

592
00:31:31.759 --> 00:31:34.839
every year go to the Australian Space Research Conference in Australia,

593
00:31:34.839 --> 00:31:37.880
which is a fabulous meeting and can be quite multidisciplinary.

594
00:31:38.519 --> 00:31:40.799
But a few years ago, I think possibly about twenty thirteen,

595
00:31:40.880 --> 00:31:46.079
twenty fourteen now, we had a invited lecture from a

596
00:31:46.319 --> 00:31:49.000
doctor who said doctor from Tasmania who works in space

597
00:31:49.079 --> 00:31:52.759
mediciner's researcher on the site. And it's the only lecture

598
00:31:52.759 --> 00:31:55.920
I've ever been to at a research conference which started

599
00:31:55.960 --> 00:31:58.279
with a trigger warning and a health warning, and that

600
00:31:58.480 --> 00:32:00.880
was basically, if there's anybody in the audience who's a

601
00:32:00.880 --> 00:32:02.880
bit squeamish, a bit sensitive, he might want to leave.

602
00:32:02.960 --> 00:32:05.160
Now this is going to be a medical talk and

603
00:32:05.279 --> 00:32:09.720
you're all astronomers and spati researchers. And it included some

604
00:32:09.880 --> 00:32:14.319
fairly unsettling pictures that I won't relay in too much detail.

605
00:32:14.400 --> 00:32:19.079
But this doctor was talking about the future aspiration of

606
00:32:19.160 --> 00:32:23.519
humanity to have a permanent presence on other astronomical bodies,

607
00:32:23.640 --> 00:32:28.279
talking particularly about Mars, and what he was speaking to

608
00:32:28.599 --> 00:32:31.759
was that our science fiction view of that is that

609
00:32:31.880 --> 00:32:34.599
you have a population on Mars that is independent, so

610
00:32:34.720 --> 00:32:38.400
they reproduce and repopulate themselves. That's what we think of,

611
00:32:39.200 --> 00:32:41.960
and he said it isn't as simple as that from

612
00:32:42.000 --> 00:32:44.519
a doctor's point of view, from someone who studied pregnancy,

613
00:32:44.720 --> 00:32:50.319
he was talking about the requirement the importance of gravity

614
00:32:50.359 --> 00:32:53.200
to pregnancy is something we never think about because we're

615
00:32:53.200 --> 00:32:55.000
all living on the surface of the Earth at one G.

616
00:32:55.920 --> 00:32:59.519
But he said it's actually the case, and remember and

617
00:32:59.640 --> 00:33:02.519
remembering to ok from more than a decade ago, he

618
00:33:02.599 --> 00:33:06.799
spoke about how important the gravity that you are moving

619
00:33:06.920 --> 00:33:10.079
within is to the development of the fetus and the

620
00:33:10.119 --> 00:33:11.880
way that the cells know what to make and what

621
00:33:12.039 --> 00:33:15.359
shape to make. And he gave the example of how

622
00:33:15.440 --> 00:33:19.839
even a very small change from the standard atmospheric temperature

623
00:33:19.880 --> 00:33:24.279
and pressure and gravity can cause huge problems by talking

624
00:33:24.279 --> 00:33:27.839
about the invasion of the Spanish into South America back

625
00:33:27.880 --> 00:33:29.759
in the sixteen hundreds and the fact that the high

626
00:33:29.799 --> 00:33:35.519
Andes were never conquered permanently because the conquistados couldn't reproduce there.

627
00:33:35.559 --> 00:33:38.920
They were just not able to be viable there, and

628
00:33:39.000 --> 00:33:42.400
the native people there had obviously adjusted over many, many generations.

629
00:33:42.799 --> 00:33:45.440
And he said, that's barely any different to the conditions here.

630
00:33:46.799 --> 00:33:49.039
What he was going on to say was that his

631
00:33:49.279 --> 00:33:52.200
vision is that because of this, this would be so

632
00:33:52.319 --> 00:33:55.279
insurmountable that for a very long time, once we have

633
00:33:55.400 --> 00:33:57.519
a permanent presence on Mars, it would be a retirement

634
00:33:57.599 --> 00:34:00.519
hard It'd be somewhere that people go to after they've

635
00:34:00.559 --> 00:34:03.240
sawed their wild arts on Earth, that they go to

636
00:34:03.359 --> 00:34:07.000
to spend their later years in a more pleasant environment

637
00:34:07.119 --> 00:34:11.320
with lower gravity, less strains on an aging, aching body.

638
00:34:12.159 --> 00:34:15.599
But he didn't see any possibility of people reproducing there

639
00:34:16.280 --> 00:34:20.599
and unless we went down the incredibly dystopian worldview of

640
00:34:20.719 --> 00:34:24.239
having women living in centrifugures for nine months to simulate

641
00:34:24.360 --> 00:34:27.440
one g which I can imagine would not be a

642
00:34:27.559 --> 00:34:32.440
very popular deficion, But it ties into Mars one, which

643
00:34:32.679 --> 00:34:36.960
was this attempt by I think a Dutch guy to

644
00:34:37.079 --> 00:34:39.639
make a lot of money out of sending a mission

645
00:34:39.679 --> 00:34:42.519
to Mars to try and get the first humans on Mars.

646
00:34:43.199 --> 00:34:45.880
And they ran a huge competition process for this with

647
00:34:45.960 --> 00:34:48.400
more than one hundred thousand initial applicants and they whittled

648
00:34:48.440 --> 00:34:50.599
them down and whittled them down. But there was an

649
00:34:50.599 --> 00:34:53.079
Australian involved in this, guy called Josh Richards, who's a

650
00:34:53.119 --> 00:34:56.000
fabulous science communicator and did a lot of work off

651
00:34:56.039 --> 00:34:58.320
the back of this of going at schools and talking

652
00:34:58.360 --> 00:34:59.960
to kids and saying I could be the first person

653
00:35:00.119 --> 00:35:03.519
on Mars ask me anything. Essentially, one of the things

654
00:35:03.559 --> 00:35:06.760
that Josh told me that led to problems and in

655
00:35:06.800 --> 00:35:08.719
the end led to the breakup of his relationship with

656
00:35:08.800 --> 00:35:11.760
his partners who went through this process was that he

657
00:35:11.960 --> 00:35:13.880
was looking at taking a one way trip to Mars,

658
00:35:14.920 --> 00:35:18.519
but also that the people who were the final selected

659
00:35:18.599 --> 00:35:22.800
ones had to agree to be medically stetilized before they

660
00:35:23.400 --> 00:35:26.800
got on the trip to Mars because they were going

661
00:35:26.840 --> 00:35:28.920
from mixed crew. The mixed crew had to make their

662
00:35:28.960 --> 00:35:32.079
own entertainment during the travels he had because his show

663
00:35:32.199 --> 00:35:34.639
was going to be delivered big brother style. That was

664
00:35:34.679 --> 00:35:37.440
probably part of the motivation for people subscribing to be honest.

665
00:35:38.760 --> 00:35:42.559
The lack of understanding of the possibilities and the risk

666
00:35:42.639 --> 00:35:46.440
of pregnancy during spatifight in microgravity or on Mars in

667
00:35:46.800 --> 00:35:50.679
incredibly reduced gravity was such a nobody could see any

668
00:35:50.719 --> 00:35:54.559
possibility of any viability of pregnancy. But it wasn't like

669
00:35:54.599 --> 00:35:56.960
they were going to send people with the medical skills

670
00:35:57.000 --> 00:35:59.719
to deal with traumatic problems like that on the mission.

671
00:36:00.440 --> 00:36:02.480
So you have to agree to either be subtilized, though

672
00:36:02.480 --> 00:36:06.440
you wouldn't go only pick someone else, which sounds really barbaric,

673
00:36:07.480 --> 00:36:09.599
but it's the unfortunate reality we're going to have to

674
00:36:09.679 --> 00:36:12.679
deal with when we start looking at having a permanent

675
00:36:12.760 --> 00:36:15.679
presence off Earth rather than just going and visit it.

676
00:36:16.320 --> 00:36:18.199
Because if we want to have a permanent presence on

677
00:36:18.280 --> 00:36:21.920
the Moon or on Mars, we view that inherently as

678
00:36:22.000 --> 00:36:24.320
humans has been a self replicating presence. We view it

679
00:36:24.360 --> 00:36:27.480
as been a presence that can sustain itself. You know,

680
00:36:27.599 --> 00:36:29.440
So if the population of Earth got wiped out, at

681
00:36:29.519 --> 00:36:32.320
least we've got the people on Mars. But in order

682
00:36:32.400 --> 00:36:34.280
to do that, it's going to need an incredible amount

683
00:36:34.320 --> 00:36:38.840
of medical research to be done and incredible advances in

684
00:36:38.920 --> 00:36:42.639
medical technology that we just don't have yet. And what's

685
00:36:42.679 --> 00:36:46.079
been asking the question here about bond density in space,

686
00:36:46.159 --> 00:36:49.119
about the role of estrogen in replacing the bonds afterwards,

687
00:36:49.159 --> 00:36:51.920
on the impact of people who are passed to premenopausal,

688
00:36:52.440 --> 00:36:54.480
that all comes into it as well, because we can't

689
00:36:54.559 --> 00:36:57.039
just do the research quite frankly, on old, middle aged

690
00:36:57.039 --> 00:37:00.480
white guys. We need to look at the averse, not

691
00:37:00.639 --> 00:37:03.840
just in terms of gender diversity, but as we move forward,

692
00:37:04.320 --> 00:37:07.639
are different groups of people better suited or worse suited

693
00:37:08.000 --> 00:37:10.960
to life in space. We know that people from different

694
00:37:11.039 --> 00:37:17.159
cultures and different countries have slightly different physiological properties. They

695
00:37:17.199 --> 00:37:18.960
will need to be researched on into this, and we'll

696
00:37:19.000 --> 00:37:21.079
need to look at people across the whole spectrum of

697
00:37:21.199 --> 00:37:24.440
humanity to understand it, rather than just basing everything on

698
00:37:24.880 --> 00:37:26.599
the first few people who went to space, who were

699
00:37:27.199 --> 00:37:31.679
pretty much uniformly very athletic, very well trained, white men

700
00:37:31.760 --> 00:37:34.800
of a certain edge. That's just been part of a subset.

701
00:37:34.880 --> 00:37:36.920
So it's a really interesting question. I don't have more

702
00:37:37.000 --> 00:37:39.880
answers than that, but really thank you for asking it.

703
00:37:40.679 --> 00:37:42.360
There's a lot to think about, and it does make

704
00:37:42.400 --> 00:37:44.400
my head hurt in a very different way to the

705
00:37:44.480 --> 00:37:46.559
cosmology mating my head hurt thing. It's a different part

706
00:37:46.639 --> 00:37:47.960
of my brain that's hurting at the minute.

707
00:37:48.320 --> 00:37:52.440
Yes, absolutely, I can tell you that when it comes

708
00:37:52.480 --> 00:37:55.639
to studies in the medicines that you referred to, my

709
00:37:55.800 --> 00:37:59.639
wife and I have experienced firsthand the effect of medicines

710
00:37:59.679 --> 00:38:05.440
that have been created and developed for men by default,

711
00:38:05.599 --> 00:38:08.599
not purposely developed for men, just developed for everybody, but

712
00:38:08.800 --> 00:38:15.679
based on the physiological male, I can take an antibiotic

713
00:38:15.760 --> 00:38:18.119
and not feel a thing. My wife can take the

714
00:38:18.159 --> 00:38:22.239
same tablet and she's sick for a day, classic example

715
00:38:22.280 --> 00:38:24.800
of it. So I know exactly what you're talking about.

716
00:38:25.039 --> 00:38:27.039
It needs to be a lot more research into medicines

717
00:38:27.199 --> 00:38:32.880
for women to suit their physiology. Also, and I can

718
00:38:33.280 --> 00:38:37.119
tell you that people on Earth suffer the same problems

719
00:38:37.159 --> 00:38:41.039
as they do in space, particularly people who are undergoing

720
00:38:41.119 --> 00:38:45.920
hormone therapy for cancer treatment. They lose muscle mass and

721
00:38:46.079 --> 00:38:50.679
bone density, and in long term therapy can develop osteoporosis.

722
00:38:51.239 --> 00:38:56.000
And the solution to that is exercise. But it's yeah,

723
00:38:56.280 --> 00:39:00.599
it's a tough battle. I'm all too aware of it myself,

724
00:39:00.880 --> 00:39:04.519
but it's yeah that it's the same problem on Earth

725
00:39:04.599 --> 00:39:07.159
when it comes to treating cancer at the moment with

726
00:39:07.320 --> 00:39:10.599
some kinds of hormone therapy. But thanks to the question,

727
00:39:10.800 --> 00:39:14.519
brilliant question. Loved it, Keep them coming. Our final question

728
00:39:14.719 --> 00:39:20.000
comes from Dan two. Dean two because we had Dean earlier. Sorry,

729
00:39:20.119 --> 00:39:21.920
Dean two, you became Dan two because you had the

730
00:39:21.960 --> 00:39:22.719
second on the list.

731
00:39:23.280 --> 00:39:26.280
This is ODID, isn't it? Parton OSSI? Dean?

732
00:39:27.039 --> 00:39:28.440
Yeah, I think so, let's find out.

733
00:39:29.039 --> 00:39:32.079
Hi, friend Andrew, this is Dean in Redcliffe and Queensland.

734
00:39:32.599 --> 00:39:34.679
Can you explain why there is a fixed amount of

735
00:39:34.760 --> 00:39:38.280
centrifugal force measurable on an object at the Earth's equator,

736
00:39:38.840 --> 00:39:41.559
But it's angular velocity which is the cause of this

737
00:39:41.679 --> 00:39:45.079
apparent force. It can only be measured relative to another

738
00:39:45.159 --> 00:39:48.880
object's frame of reference. What I mean is an eighty

739
00:39:48.960 --> 00:39:51.480
k g person should weigh about three hundred grams less

740
00:39:51.519 --> 00:39:53.719
at the equator than at the poles, and this can

741
00:39:53.760 --> 00:39:57.760
be measured. However, the calculation for centrifugal force uses the

742
00:39:57.920 --> 00:40:01.679
angular velocity of the person going around the Earth's axis,

743
00:40:02.360 --> 00:40:05.119
which is measured using the frequency of the Earth spin.

744
00:40:06.079 --> 00:40:08.679
Whether the Earth's diameter and circumference are fixed. The Earth

745
00:40:08.760 --> 00:40:11.960
spins once in twenty four hours relative to the Sun,

746
00:40:12.280 --> 00:40:15.360
once in twenty four hours forty minutes relative to the Moon,

747
00:40:16.199 --> 00:40:19.119
and once in twenty three hours fifty six minutes relative

748
00:40:19.159 --> 00:40:23.760
to distant starts. Although these frequencies are all fairly close,

749
00:40:24.559 --> 00:40:27.360
they would each give different answers to the calculation. Yet

750
00:40:27.400 --> 00:40:30.519
we can measure centrifuge before so as a fixed amount.

751
00:40:31.559 --> 00:40:36.159
Although objects in all objects in space are moving, I

752
00:40:36.239 --> 00:40:39.800
suspect that space itself does not move, even though it's expanding,

753
00:40:40.599 --> 00:40:43.960
So does space time have a fixed structure that determines

754
00:40:44.039 --> 00:40:48.960
direction without reference to objects within it? Thanks for the podcast.

755
00:40:49.880 --> 00:40:54.079
Wow, Thanks Dean. We sort of hinted its centrifugal horser earlier,

756
00:40:54.159 --> 00:40:56.360
but this is a kind of this is a different

757
00:40:56.400 --> 00:40:56.960
angle on it.

758
00:40:57.039 --> 00:41:00.800
Bomb bomb, bom bomb. It's an all question and there's

759
00:41:00.800 --> 00:41:04.119
a couple of different parts to Itsel'll initially talk about

760
00:41:04.360 --> 00:41:07.440
the effect of the Earth's rotation on your weight. I

761
00:41:07.480 --> 00:41:10.960
think that's a good one in terms of the dependens

762
00:41:11.159 --> 00:41:14.519
on a reference frame. There isn't really dependence on a

763
00:41:14.599 --> 00:41:18.559
reference frame for it, because what we measure is what

764
00:41:18.760 --> 00:41:23.119
is actually happening. So the Earth rotates at a certain speed,

765
00:41:23.679 --> 00:41:26.440
and because you're moving at that speed, you've got gravity

766
00:41:26.519 --> 00:41:30.719
pulling you down. But the movement that you've got the rotation,

767
00:41:31.280 --> 00:41:33.960
is carrying you off at right angles to gravity, and

768
00:41:34.079 --> 00:41:36.119
you're kind of falling around as you go around. So

769
00:41:36.800 --> 00:41:38.920
because you're not falling into the Earth, but you're also

770
00:41:39.159 --> 00:41:41.960
not escaping from the Earth bause of your movement. So

771
00:41:42.119 --> 00:41:44.519
so there's a little bit of an outward false balancing

772
00:41:44.639 --> 00:41:47.679
gravity that's the net result of it. So we can

773
00:41:47.719 --> 00:41:50.320
work this through with all the mass, and I sometimes

774
00:41:50.360 --> 00:41:52.920
do this derivation from my students. It's kind of vaguely

775
00:41:52.960 --> 00:41:55.760
elegant to get the orbital period for things, you can

776
00:41:55.960 --> 00:42:00.599
do this kind of mass. What's effectively happening are is

777
00:42:00.639 --> 00:42:04.599
that you have an acceleration going on. You're an accelerating

778
00:42:04.679 --> 00:42:08.079
object and because of your motion as you rotate around

779
00:42:08.119 --> 00:42:10.559
the Earth, you do one full lap in a certain

780
00:42:10.559 --> 00:42:13.559
amount of time. That means it is as though you're

781
00:42:13.559 --> 00:42:16.320
being pulled towards the middle with the acceleration, and that's

782
00:42:16.360 --> 00:42:19.360
the acceleration due to gravity you feel, and the faster

783
00:42:19.440 --> 00:42:23.519
you spin, the lower that pull towards the middle feels like.

784
00:42:23.639 --> 00:42:27.199
This is because you're offset by the centrifugal force, so

785
00:42:27.239 --> 00:42:29.400
you feel, which is a virtual force, feeling like it's

786
00:42:29.440 --> 00:42:35.159
pushing outwards. By comparison, the real number you measure is

787
00:42:35.280 --> 00:42:38.599
based around what the acceleration on your body actually is,

788
00:42:38.679 --> 00:42:42.239
and that's something that's quantifiable and that is down to

789
00:42:42.360 --> 00:42:46.239
you completing exactly one lap of the Earth in the

790
00:42:46.360 --> 00:42:50.079
reference frame of the Earth. So that's the one thing

791
00:42:50.159 --> 00:42:52.039
that was missing from this. We talk about the sun,

792
00:42:52.119 --> 00:42:54.320
we talk about the distance sounds, we talk about the moon,

793
00:42:54.639 --> 00:42:57.960
but in reality you're talking about in the Earth's rest frame.

794
00:42:58.400 --> 00:43:00.639
So you're going around in a circle around the center

795
00:43:00.719 --> 00:43:04.119
of the Earth. That takes you twenty three hours, fifty

796
00:43:04.119 --> 00:43:07.599
six minutes and four seconds. The distance stars are just

797
00:43:07.679 --> 00:43:09.599
a reference point where we can see that for but

798
00:43:09.639 --> 00:43:12.400
it's all relative to the position of the Earth, and

799
00:43:12.519 --> 00:43:15.320
so that's what gives you your three hundred grams less.

800
00:43:16.440 --> 00:43:19.239
The Sun and the Moon are also moving in the

801
00:43:19.320 --> 00:43:22.440
rest frame of the Earth. The Sun does one full

802
00:43:22.519 --> 00:43:25.079
lap around the Earth in one year, the moon does

803
00:43:25.159 --> 00:43:27.840
one full lap in one month. So that's why you've

804
00:43:27.840 --> 00:43:29.960
got those slightly longer times, because you have got to

805
00:43:30.000 --> 00:43:32.280
turn a little bit more than one full revolution before

806
00:43:32.320 --> 00:43:35.079
the Sun is directly overhead or before the moon is

807
00:43:35.119 --> 00:43:37.800
directly overhead. So that isn't a red frame. That's a

808
00:43:37.920 --> 00:43:41.639
moving frame. That's a rotating frame. Essentially, if you measure

809
00:43:41.679 --> 00:43:44.239
it with respect to the sunbeam overhead, the whole of

810
00:43:44.320 --> 00:43:46.800
the Earth's frame has had to rotate around. In that case,

811
00:43:47.920 --> 00:43:50.400
it brings us onto the concepts of rest frames and

812
00:43:51.079 --> 00:43:54.559
how you measure them on what is the universal rest frame.

813
00:43:56.360 --> 00:44:00.719
That's again where it gets really really headachey. Now my knowledge,

814
00:44:00.760 --> 00:44:05.440
it isn't thought in any of the models of space time,

815
00:44:06.199 --> 00:44:10.079
but space time is fixed and distinct from the objects

816
00:44:10.360 --> 00:44:14.400
within it. Rather, any object that is moving at a

817
00:44:14.480 --> 00:44:21.760
fixed speed and not experiencing any acceleration is in a

818
00:44:21.840 --> 00:44:26.679
rest frame. It's at rest locally, it's not accelerating, and

819
00:44:26.800 --> 00:44:29.639
so it can look out at the entire universe from

820
00:44:29.719 --> 00:44:34.039
its perspective, and any accelerations that it sees and any

821
00:44:34.039 --> 00:44:36.800
emotions that it sees are what's actually happening out there.

822
00:44:37.800 --> 00:44:39.960
If you're in an accelerating rest frame, you are not

823
00:44:40.079 --> 00:44:43.400
in a rest frame by definition, because you're accelerating. So

824
00:44:43.960 --> 00:44:46.519
a person on the surface of the Earth is accelerating

825
00:44:46.559 --> 00:44:49.239
as we go around the Earth, as the Earth rotates,

826
00:44:49.840 --> 00:44:51.719
and as the Earth goes around the Sun, and as

827
00:44:51.760 --> 00:44:53.880
the Earth orbits in the central mass of the Earth,

828
00:44:53.960 --> 00:44:56.639
Moon System, and all the rest of it. So we're

829
00:44:56.679 --> 00:44:59.760
not actually in what I think is often described as

830
00:44:59.760 --> 00:45:04.920
an inertial threat. However, you do a lot of thought

831
00:45:05.000 --> 00:45:08.559
experiments that are near enough. If you were free floating

832
00:45:08.639 --> 00:45:11.480
in space away from any of the stars, you'd probably

833
00:45:11.519 --> 00:45:13.599
consider yourself to be an inertial friend. But even then

834
00:45:13.599 --> 00:45:18.320
you'd have some acceleration from the stars. There isn't really

835
00:45:18.559 --> 00:45:19.880
as far as I know. And this is where we

836
00:45:19.920 --> 00:45:23.239
get onto the cosmology stuff, which is more wooly for me.

837
00:45:23.519 --> 00:45:26.199
And so I'm giving a less accurate and less good

838
00:45:26.280 --> 00:45:29.199
quality answer, and I apologize for that. But there isn't,

839
00:45:29.239 --> 00:45:33.599
to my knowledge, any universe accepted rest threat, because everything

840
00:45:33.719 --> 00:45:36.280
is moving and everything is accelerating and feeling the gravity

841
00:45:36.320 --> 00:45:39.679
of everything else. But the way that our models of

842
00:45:39.760 --> 00:45:43.840
the universe work is that they have this concept of

843
00:45:43.920 --> 00:45:46.039
space time, but it isn't like space time is a

844
00:45:46.480 --> 00:45:49.360
fabric that is physical over which everything moves. It is

845
00:45:49.400 --> 00:45:53.400
itself fixed, even space time is moving and dragged around.

846
00:45:54.360 --> 00:45:58.079
I'm aware that this is an answer that's quickly evolving

847
00:45:58.159 --> 00:46:01.039
from sensible into the incohera, and that's because this is

848
00:46:01.079 --> 00:46:03.920
pushing the limits of what my knowledge is. But it's

849
00:46:03.960 --> 00:46:07.480
also pushing the conceptual limits on which we build the

850
00:46:07.519 --> 00:46:10.960
foundations and stuff. And that's because a lot of the models,

851
00:46:10.960 --> 00:46:12.559
and particularly a lot of the way the models we

852
00:46:12.760 --> 00:46:17.280
use are described, we simplify things to make it clearer

853
00:46:17.360 --> 00:46:21.239
how everything works. You know, So we talk about an

854
00:46:21.280 --> 00:46:24.280
object at rest, you know, people are explaining special relativity

855
00:46:24.440 --> 00:46:26.760
for the first time. We'll talk about an object at

856
00:46:26.800 --> 00:46:29.280
rest and another object moving in a finite speed that

857
00:46:29.400 --> 00:46:31.880
is near the speed of like relative to it, and

858
00:46:31.960 --> 00:46:35.119
that's a great thought experiment. The reality is a lot

859
00:46:35.199 --> 00:46:37.719
of the time that we are so close to being

860
00:46:37.760 --> 00:46:40.199
in that situation that you can ignore the effects of

861
00:46:40.320 --> 00:46:43.800
the little bits at per turbit unless you've got incredibly

862
00:46:43.800 --> 00:46:46.599
good measuring equipment. So from the point of view of

863
00:46:46.880 --> 00:46:49.840
to totally switch analogies, I was watching the cricket the

864
00:46:49.880 --> 00:46:52.960
other night. If you imagine two cricketers and somebody running

865
00:46:52.960 --> 00:46:56.360
in and bowling the cricket ball, but instead of it bouncing,

866
00:46:56.360 --> 00:46:58.079
it just goes straight on. So it's a full toss.

867
00:46:58.079 --> 00:47:01.760
It's a beamer, nasty delivery, booh hiss, yeah, very all

868
00:47:01.800 --> 00:47:04.639
the rest of it. The only thing that is going

869
00:47:04.679 --> 00:47:07.280
on in terms of predicting the trajectory of that ball

870
00:47:08.000 --> 00:47:10.079
is that it has that soleration pulling it down. There's

871
00:47:10.119 --> 00:47:13.159
a little bit of air resistance as well. If the

872
00:47:13.199 --> 00:47:15.440
ball spinning, you get benula effects and things that can

873
00:47:15.519 --> 00:47:18.639
cause it swerve. But that ball is moving, and we

874
00:47:18.719 --> 00:47:21.440
can treat it as though the cricket pitch and all

875
00:47:21.480 --> 00:47:23.920
of the players are in a shared inertial rest frame.

876
00:47:24.599 --> 00:47:27.199
There's nothing else going on. Other than this single gravitational

877
00:47:27.280 --> 00:47:30.159
force pulling down. We don't have to take account of

878
00:47:30.239 --> 00:47:34.039
things like the Coriolis effect, which is another virtual force,

879
00:47:34.159 --> 00:47:36.559
like the centrifugal force that is the result of the

880
00:47:36.679 --> 00:47:39.159
rotation of the Earth and the different rotation speeds at

881
00:47:39.199 --> 00:47:42.760
different latitudes. We can treat that in a local, isolated

882
00:47:42.920 --> 00:47:45.840
case as though it is a much simpler scenario than

883
00:47:45.880 --> 00:47:47.760
it is, because all those are the corrections that so

884
00:47:47.960 --> 00:47:52.360
small that they don't really impact things. What it leads to, though,

885
00:47:52.480 --> 00:47:55.159
is we tend to explain things using those simpler things,

886
00:47:55.599 --> 00:48:00.559
simpler scenarios, and that leads to questions like this, because

887
00:48:00.559 --> 00:48:04.280
it leads to the idea that there is something external

888
00:48:04.400 --> 00:48:07.159
to the Earth and the Sun and towards those observers

889
00:48:07.960 --> 00:48:11.760
that is in itself fixed, and that there is an absolute,

890
00:48:11.960 --> 00:48:15.920
idealized frame of reference. My understanding is that all of

891
00:48:16.000 --> 00:48:18.800
our models do not argue that. When you get into

892
00:48:18.800 --> 00:48:23.039
the nitty grittic it's a will the answer. I appreciate,

893
00:48:23.039 --> 00:48:25.599
it's probably not an ideal answer, Deane. And you know,

894
00:48:25.760 --> 00:48:28.440
if that answer was not satisfactory, if you please ask

895
00:48:28.559 --> 00:48:31.679
Fred when he's back and get a different version. I

896
00:48:31.800 --> 00:48:33.920
do think this is important for anybody who's learning. Actually,

897
00:48:33.960 --> 00:48:35.639
I say this to my atudents. I've got a tutor

898
00:48:35.760 --> 00:48:37.400
in a couple of hours which I'm thinking of this

899
00:48:37.480 --> 00:48:42.039
head space. My explanations are one explanation of how things work,

900
00:48:42.480 --> 00:48:44.840
and they'll work for some people. But we all think

901
00:48:44.840 --> 00:48:46.960
about the universe differently, and there is no shame in

902
00:48:47.039 --> 00:48:50.960
saying that explanation did work for me. Let me find another. Yeah,

903
00:48:51.440 --> 00:48:55.400
it's really important. If my explanation of that, which admittedly

904
00:48:56.000 --> 00:48:58.599
you know was probably not a perfect explanation even for me,

905
00:48:59.599 --> 00:49:02.840
doesn't work for you, there will be other explanations around,

906
00:49:02.880 --> 00:49:05.360
and it's worth asking another person to get a different

907
00:49:05.360 --> 00:49:08.440
perspective of what I said that didn't make sense. There

908
00:49:08.519 --> 00:49:10.199
is no problem with that. I will not be offended

909
00:49:10.239 --> 00:49:12.440
if you ask Fred in two weeks and say, John

910
00:49:12.480 --> 00:49:15.159
Ty fail to explain this, his explanation was rubbish. Tellney

911
00:49:15.199 --> 00:49:17.800
what's really happening, Fred, and then let him go and

912
00:49:17.840 --> 00:49:18.559
see what happens.

913
00:49:20.920 --> 00:49:25.039
Okay, fair enough, great question, very deep thinking. They're Dean,

914
00:49:25.159 --> 00:49:27.480
and thanks for sending it in. If you'd like to

915
00:49:27.519 --> 00:49:29.840
send us a question, you can do that on our website,

916
00:49:29.920 --> 00:49:32.559
space nuts podcast dot com or space nuts dot io.

917
00:49:32.760 --> 00:49:35.239
Click on the AMA button up the top, and you

918
00:49:35.280 --> 00:49:37.639
can send us text and audio questions and have a

919
00:49:37.679 --> 00:49:40.119
look around while you're there. You're always welcome to our

920
00:49:40.199 --> 00:49:43.800
website or our social media on Facebook or Instagram or

921
00:49:44.400 --> 00:49:48.559
YouTube if you're a YouTube follower. Thanks to your support,

922
00:49:48.599 --> 00:49:52.639
we've got quite a large audience on YouTube these days.

923
00:49:55.599 --> 00:49:55.880
That's it.

924
00:49:56.079 --> 00:49:58.360
Oh, we've done. I was looking for another question, Johnny,

925
00:49:58.440 --> 00:49:59.280
Thank you so much.

926
00:50:00.000 --> 00:50:02.280
That stuff STI pleasure. Obviously didn't talk too much today.

927
00:50:02.760 --> 00:50:03.960
First time for everything.

928
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You might want to look at the time ticking up

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here on my clock. Thanks Joddy. We'll catch you next time.

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Johnny Horner, Professor of astrophysics at the University of Southern Queensland.

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And thanks to Heu in the studio who couldn't be

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with us again today because he was over producing me

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sane he'll be out of hospital soon, and from me

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Andrew Andrew Dunkley, thanks to your company. See you on

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the next episode of Space Nuts. Goodbye space.

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You'll be listening to the Space Nuts.

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Podcast available at Apple Podcasts, Spotify, iHeart Radio, or your

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favorite podcast player. You can also stream on demand at

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00:50:43.480 --> 00:50:44.360
bides dot com.

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00:50:44.920 --> 00:50:48.519
This has been another quality podcast production from nights dot

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com
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