Theia’s Fate, Galaxy Mergers & the Mysteries of Mars’ Atmosphere | Q&A | Space Nuts: Astronomy...

WEBVTT
Kind: captions
Language: en

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Hello again. Thanks for joining us on a


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Q&A edition of Space Nuts. My name is


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Andrew Dunley and today we will be I


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won't Fred will be answering questions


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about uh the former planet known as


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Thea. Uh galaxy merges have come up. Um,


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we go back to Mars uh with a theory


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about Olympus Mons and why only


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hydrogen? That is a question uh that


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comes from, I believe, a 5-year-old.


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We'll deal with all of that today on


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this edition of Space Nuts.


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>> 15 seconds. Guidance is internal. 10 9g


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Ignition sequence start.


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>> Space Nuts. 5 4 3 2


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>> 1 2 3 4 5 5 4 3 2 1


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>> Space Notes astronauts report at Bills


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Good.


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>> And to solve all of those little


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riddles, we're joined again by Professor


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Fred Watson, astronomer at large. Hello,


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Fred.


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>> Hello, Andrew. Very good to see you


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again.


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>> Good to see you, too. We've got a bit of


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weird noise on your line. I I think it's


00:01:05.680 --> 00:01:07.190
probably just the internet being the


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internet, so hopefully that'll go away.


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>> In fact, it just did. So, yeah. There


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you go. solved itself. It must have


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heard me winging.


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>> All is well, I assume.


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>> Uh yeah, we're doing fine. Thank you. Uh


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it's good to join you on the questions


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episode of uh what's this called again?


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Oh, Space Nuts. That's right.


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>> Space idiots. Uh Space Nuts. Yes. Yeah.


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No, they're all good people. Uh we might


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as well jump in straight away to our


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first question, and it comes from one of


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our regular contributors. It's Rusty.


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Good day, Fred and Andrew. It's Rusty in


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Donny Brook. I've been listening to your


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latest episode


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where you look at the relationship


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between Sea and the Earth before the


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collision. And I just want to make sure


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I've got the story straight, so I'll put


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it in my own words. The Earth had a


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buddy named Thea who came a little too


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near. She hit with a splash, then made


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off with a dash. But there's no mooning


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for Thea around here. So, what happened


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to Thea after the collision? The


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theories prior to this revelation said


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Thea had enough kinetic energy to leave


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the solar system altogether. But if the


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orbits were so close, that doesn't seem


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likely. So, it seems to me there's three


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possibilities


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that Thea fell into the sun, which would


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be another amazing feat to get that uh


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sort of precision after the collision.


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Sea picked up a little slingshot energy


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and moved out further and became Mars.


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Now, Mars is a Mars size object after


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all. And the third possibility I can


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think of is that it picked up an


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unlikely amount of kinetic energy and


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became


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planet 9. So, if it did become planet 9,


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it would have a highly eccentric orbit


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because it's too far away for us to


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actually see at the moment. But would


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this orbit then at some stage bring it


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back uh to the inner solar system of its


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origin?


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>> That's it. Hope you guys are well.


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Cheers.


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>> Thanks, Rusty. Hope you're well, too. Uh


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over there in WA. Um what happened to


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Thea? He's come up with some interesting


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theories. Uh quite a few ideas. I I'm


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guessing they can't all be true.


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Um, I think that's right. There's


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there's actually a fourth possibility


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>> uh added to the three that uh that Rusty


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has


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proposed. Uh, and I think that's the one


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that's usually accepted and there's kind


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of evidence for that. Uh, the fourth


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possibility is that the basically was


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absorbed into the earth. the remnants of


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the air uh are actually in the earth's


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mantle. And in fact uh there's something


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called and there are two of these uh a


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large low sheer velocity province in the


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earth's lower mantle and the hypothesis


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is that that is the remnants of the


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year. uh so that we still see the


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evidence of that collision by anomalies


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basically in the earth's mantle which we


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investigate seis you know with


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seismology that's how we know about


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what's going on in the mantle of the


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earth it's how we know about large low


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sheer velocity provinces um uh I'm kind


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of just using the words here because I'm


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not somebody who knows about the inside


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of the planet uh other than the the the


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you know the sketchiest outline uh of a


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core, a mantle and uh and a crust. But


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uh the mantle we know has significant


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structure. Uh and in fact um Manny and I


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have a a good friend um who Nick Pford


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who is a volcanologist and he's somebody


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who looks at these velocity structures


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in the uh in the mantle of the earth uh


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and you know the the upwelling of


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material to form volcanoes and things


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like that. Uh next time we see Nick I


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will ask him about these large scale low


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velocity shear areas uh and uh their


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relationship to the but I think that's


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the consensus uh Rusty that uh the


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impact basically uh resulted in an


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explosion uh which shed uh something


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like um I think one of the suggestions


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is about 70 70%


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uh of the mass of the moon uh may have


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come from thea. I'm actually um um I


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think that might


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let's let's put it this way. Thea is


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responsible for 70 to 90% of the total


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mass of the moon under the classic giant


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impact scenario


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where thea is considerably smaller than


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a proto earth which it would have been.


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Uh the earth was still kind of earthish


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sized. Thea was Marsish sized. Uh but


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the earth would have probably grown a


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bit by absorbing uh the debris from the


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uh remember that the the mass of the


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moon is about 180th of the mass of the


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earth.


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>> Uh so it's a significantly large body


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compared with the other moons in the


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solar system. Uh but uh it's it's


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clearly smaller than uh you know it's


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not Mars sized. And so Rusty's right in


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that that, you know, the remnants of the


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had to do something, but the current


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theory is that they were absorbed by the


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proto Earth and we can still see


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evidence for them.


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>> Yeah. Um


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Okay. So yeah, definitely not likely to


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be P9. That would be a very


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odd kind of occurrence, wouldn't it?


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>> Yeah. Well, yes. Um I I think the


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kinematics don't work. you you you know


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you you you can't give it enough


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velocity and you need you need a lot of


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velocity for it to fall back into the


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sun as well too too much energy that's


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quite an energetic process is is getting


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rid of the orbital velocity of a body to


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make it fall into the sun it's you know


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you need as much energy as you do to get


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it pushed out uh to the outer planet so


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>> yeah um didn't we talk about it once


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before and suggest that remnants of it


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just probably speared off into case


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never to be seen again. I


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>> I'm sure there would have been an


00:08:02.240 --> 00:08:04.550
element of that. Yes. And you know that


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that debris cloud that eventually formed


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the moon probably lost some of its some


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of its uh material content. Uh and it


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there may even be stuff wandering around


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uh in the form of nearear asteroids now


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that are bits and pieces that are left


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over from that. But remember this was


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you know this was within the first


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couple hundred million years of the


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history of the solar system. So, you're


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talking about things that happened a


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very long time ago.


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>> Yeah, indeed. Um, I'm I'm wondering,


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Fred, why we've just got this sudden


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influx of people asking questions in


00:08:39.360 --> 00:08:44.149
poem. This is I'm blaming uh Martin for


00:08:44.159 --> 00:08:46.630
that. Martin Burman Gorvine, you started


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this and now it's taking


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>> I actually think um I I I really liked


00:08:51.040 --> 00:08:53.030
Russ Rusty's one there about the I


00:08:53.040 --> 00:08:54.389
thought that was very nice.


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>> Yeah. I don't know. I think he pushed it


00:08:55.920 --> 00:08:57.430
a bit on one of those one of those


00:08:57.440 --> 00:09:00.230
rhymes. Yeah. Um although there there


00:09:00.240 --> 00:09:01.829
was a regular guest and I'm sure you


00:09:01.839 --> 00:09:03.269
know who I'm talking about. Cole Wilson


00:09:03.279 --> 00:09:04.949
who used to join us on the radio once a


00:09:04.959 --> 00:09:07.509
week to do um bush poetry.


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>> She blew the sheer and he often got


00:09:09.760 --> 00:09:11.590
asked to do shearing demonstrations and


00:09:11.600 --> 00:09:12.790
he had to tell them look I'm not a


00:09:12.800 --> 00:09:15.110
sheer. I can't shear a sheep to save my


00:09:15.120 --> 00:09:18.630
life. It's just my show name. But he he


00:09:18.640 --> 00:09:22.070
used to actually invent words to create


00:09:22.080 --> 00:09:24.470
rhymes.


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It was one of his wonderful traits and


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um yeah uh I used to spend a lot of time


00:09:29.920 --> 00:09:32.949
with Cole. He's a terrific bloke. Um I


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think we've dealt with Rusty's uh


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theories and they were all wrong.


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>> Thanks Rusty.


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>> Thanks Rusty. Great to hear from you.


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>> Swift


00:11:13.839 --> 00:11:16.069
base here. The angle has landed.


00:11:16.079 --> 00:11:17.590
>> Space nets.


00:11:17.600 --> 00:11:19.829
>> Let's move on to our next question and


00:11:19.839 --> 00:11:22.710
this one I've lost. Uh here it is. Uh


00:11:22.720 --> 00:11:24.710
this comes from Lena. I am a new


00:11:24.720 --> 00:11:27.670
listener and not as hardcore a space nut


00:11:27.680 --> 00:11:30.230
as most of your audience. Uh it's


00:11:30.240 --> 00:11:32.150
probably a good thing. Uh but I saw an


00:11:32.160 --> 00:11:34.310
article today talking about merging


00:11:34.320 --> 00:11:36.870
spiral galaxies. If the universe is


00:11:36.880 --> 00:11:38.949
expanding, how does something as large


00:11:38.959 --> 00:11:42.150
as a galaxy move toward and merge with


00:11:42.160 --> 00:11:44.150
another galaxy? It seems they should be


00:11:44.160 --> 00:11:46.630
moving further away from each other. Uh


00:11:46.640 --> 00:11:48.790
that comes from Molina in British


00:11:48.800 --> 00:11:53.190
Columbia in Canada. Uh I think we've had


00:11:53.200 --> 00:11:55.350
questions of this ilk before, but it's


00:11:55.360 --> 00:11:57.350
always good to go over it again because


00:11:57.360 --> 00:11:59.190
there's a lot more going on in the


00:11:59.200 --> 00:12:01.670
universe than just, you know, spreading


00:12:01.680 --> 00:12:04.069
out like school children playing what's


00:12:04.079 --> 00:12:06.310
that game where you don't, you know, I


00:12:06.320 --> 00:12:08.310
don't know what you call it. Um


00:12:08.320 --> 00:12:09.750
something you throw a ball and try and


00:12:09.760 --> 00:12:12.790
hit someone in the head. Anyway, go on.


00:12:12.800 --> 00:12:14.629
That's cricket, isn't it?


00:12:14.639 --> 00:12:18.550
>> No. No. Dodgeball. Dodgeball. And And


00:12:18.560 --> 00:12:20.150
there's a whole bunch of games like


00:12:20.160 --> 00:12:22.550
that. Like, uh, Red Rover Crossover. Did


00:12:22.560 --> 00:12:23.910
you ever play that?


00:12:23.920 --> 00:12:26.470
>> Uh, we Oh, no. We used to have a lot of


00:12:26.480 --> 00:12:28.230
fun with that.


00:12:28.240 --> 00:12:31.030
>> Um, anyway, uh, look, Lena's question is


00:12:31.040 --> 00:12:34.069
a great one. And I I guess the the


00:12:34.079 --> 00:12:36.629
simplest answer here is that yes,


00:12:36.639 --> 00:12:39.750
galaxies are big, but they're tiny


00:12:39.760 --> 00:12:43.190
compared with the universe. And so the


00:12:43.200 --> 00:12:44.949
expansion of the universe is something


00:12:44.959 --> 00:12:48.150
that we look at on very large scales.


00:12:48.160 --> 00:12:50.150
You know, you're looking out billions of


00:12:50.160 --> 00:12:53.670
light years uh and seeing this


00:12:53.680 --> 00:12:56.470
expansion. It's actually with today's


00:12:56.480 --> 00:12:57.829
technology, it's one of the easiest


00:12:57.839 --> 00:13:00.230
observations that you can make uh that


00:13:00.240 --> 00:13:02.710
the universe is expanding. Discovered um


00:13:02.720 --> 00:13:06.949
back in 1929 by Edwin Hubble. Uh so uh


00:13:06.959 --> 00:13:08.870
yes so if the universe is expanding, if


00:13:08.880 --> 00:13:11.350
space is getting bigger and naturally


00:13:11.360 --> 00:13:12.870
carrying things further and further


00:13:12.880 --> 00:13:14.949
apart, why are some galaxies coming


00:13:14.959 --> 00:13:16.870
towards each other? And it's because on


00:13:16.880 --> 00:13:19.670
the scale of a galaxy, the expansion of


00:13:19.680 --> 00:13:23.350
the universe is minuscule. Uh and the by


00:13:23.360 --> 00:13:26.310
far the dominant um the dominant process


00:13:26.320 --> 00:13:30.949
is gravity. Uh so um galaxies which yes


00:13:30.959 --> 00:13:34.150
are being carried uh gradually apart by


00:13:34.160 --> 00:13:36.629
the by the expansion of the universe


00:13:36.639 --> 00:13:38.470
when you put them close together their


00:13:38.480 --> 00:13:40.310
own gravity gives them a force that


00:13:40.320 --> 00:13:43.590
pulls them together that's much greater


00:13:43.600 --> 00:13:46.550
uh than the expansion. Um and we


00:13:46.560 --> 00:13:48.870
actually give that a name. We call this


00:13:48.880 --> 00:13:51.030
the peculiar velocities of galaxies


00:13:51.040 --> 00:13:52.790
because it's a velocity peculiar to an


00:13:52.800 --> 00:13:55.110
individual galaxy. And the usual way


00:13:55.120 --> 00:13:57.430
that we describe it and I think we've


00:13:57.440 --> 00:13:59.269
talked about this before on space nuts


00:13:59.279 --> 00:14:04.629
is um if you imagine a river flowing uh


00:14:04.639 --> 00:14:06.629
which represents the kind of expansion


00:14:06.639 --> 00:14:08.389
of the universe and then somebody in a


00:14:08.399 --> 00:14:10.710
boat is moving around on the river.


00:14:10.720 --> 00:14:12.470
They're being carried downstream by the


00:14:12.480 --> 00:14:14.069
river's movement but they've got their


00:14:14.079 --> 00:14:16.550
own movement provided by the boat on the


00:14:16.560 --> 00:14:19.189
water. Uh and it's a bit like that with


00:14:19.199 --> 00:14:21.030
galaxies. They're being carried along by


00:14:21.040 --> 00:14:23.189
the expansion of the universe. But a far


00:14:23.199 --> 00:14:25.910
bigger effect is the way gravity pulls


00:14:25.920 --> 00:14:28.310
them together. So that's what's pulling


00:14:28.320 --> 00:14:30.310
our galaxy and the Andromeda galaxy


00:14:30.320 --> 00:14:32.550
together. Uh it's the gravitational


00:14:32.560 --> 00:14:35.269
force between them. Uh and on the scale


00:14:35.279 --> 00:14:38.150
of the distance between uh Andromeda and


00:14:38.160 --> 00:14:39.750
our own galaxy, which is about two and a


00:14:39.760 --> 00:14:41.590
half million light years. Uh the


00:14:41.600 --> 00:14:43.670
expansion of the universe makes


00:14:43.680 --> 00:14:45.590
virtually no difference. Uh you only


00:14:45.600 --> 00:14:47.350
start really noticing it when you get to


00:14:47.360 --> 00:14:49.829
much bigger bigger scales. Yeah, but


00:14:49.839 --> 00:14:52.069
there will come a point in time where


00:14:52.079 --> 00:14:55.350
all these galaxy merges will finish.


00:14:55.360 --> 00:14:57.269
They'll be done and dusted and the


00:14:57.279 --> 00:14:59.350
universe will keep expanding and


00:14:59.360 --> 00:15:02.870
eventually there'll just be darkness.


00:15:02.880 --> 00:15:03.990
There'll be nothing.


00:15:04.000 --> 00:15:07.590
>> Yeah. If that's assuming dark energy,


00:15:07.600 --> 00:15:08.870
>> a big crunch. Oh, right.


00:15:08.880 --> 00:15:10.949
>> Yeah. I mean, dark energy, we're now


00:15:10.959 --> 00:15:12.550
just starting to see the first signs


00:15:12.560 --> 00:15:14.470
that maybe over the last few billion


00:15:14.480 --> 00:15:17.670
years it's decreased. uh and so the


00:15:17.680 --> 00:15:19.829
acceleration of the universe it's still


00:15:19.839 --> 00:15:21.829
accelerating the expansion is still


00:15:21.839 --> 00:15:24.710
getting faster but it's getting faster


00:15:24.720 --> 00:15:27.430
at a slower rate if I put it that way.


00:15:27.440 --> 00:15:29.509
So the acceleration itself looks as


00:15:29.519 --> 00:15:31.590
though it's declining and that's why


00:15:31.600 --> 00:15:33.030
some people are still talking about the


00:15:33.040 --> 00:15:36.629
big crunch or the gab gib again. Um it's


00:15:36.639 --> 00:15:38.310
uh it's because if it if the


00:15:38.320 --> 00:15:40.710
acceleration eventually goes away and


00:15:40.720 --> 00:15:42.550
becomes a deceleration then yeah you're


00:15:42.560 --> 00:15:44.069
going to get a big crunch.


00:15:44.079 --> 00:15:46.790
>> Yeah. Yeah. It's, you know, could go


00:15:46.800 --> 00:15:48.470
either way at this stage. The way that


00:15:48.480 --> 00:15:52.230
they're talking, we we have witnessed um


00:15:52.240 --> 00:15:54.550
some galaxy merges, haven't we? Doesn't


00:15:54.560 --> 00:15:56.790
our own galaxy actually contain a couple


00:15:56.800 --> 00:15:59.030
of other galaxies that have been sucked


00:15:59.040 --> 00:16:00.629
into our void.


00:16:00.639 --> 00:16:02.550
>> Yeah. Two quite big ones actually. What


00:16:02.560 --> 00:16:04.710
the things we call the large and small


00:16:04.720 --> 00:16:08.310
melanic clouds. Uh they are satellite


00:16:08.320 --> 00:16:09.910
galaxies of our own and they're being


00:16:09.920 --> 00:16:12.389
stripped of their stars by uh our own


00:16:12.399 --> 00:16:15.590
galaxy. its gravitational pool uh and


00:16:15.600 --> 00:16:17.829
will eventually be part of the halo of


00:16:17.839 --> 00:16:21.430
our own galaxy. But we see we also see


00:16:21.440 --> 00:16:24.389
examples in deep space of big galaxies


00:16:24.399 --> 00:16:26.230
actually merging. The most famous is the


00:16:26.240 --> 00:16:29.590
the antenna galaxies, two galaxies which


00:16:29.600 --> 00:16:32.550
are merging and pulling off spiral arms


00:16:32.560 --> 00:16:35.430
off each other quite a fashion.


00:16:35.440 --> 00:16:37.509
>> Yeah, it all happens in slow motion


00:16:37.519 --> 00:16:39.990
though, doesn't it? and um and and and


00:16:40.000 --> 00:16:41.670
when people talk, you know, think about


00:16:41.680 --> 00:16:43.590
galaxy merger merges, they're thinking


00:16:43.600 --> 00:16:46.550
all this um drama and collisions and but


00:16:46.560 --> 00:16:48.949
it it generally doesn't turn out that


00:16:48.959 --> 00:16:50.629
way. Well, you're talking about


00:16:50.639 --> 00:16:52.710
processes that take millions of years


00:16:52.720 --> 00:16:54.230
and uh


00:16:54.240 --> 00:16:56.790
>> yeah, and um you know, it's and and in


00:16:56.800 --> 00:16:59.350
fact galaxies probably when they


00:16:59.360 --> 00:17:01.030
collide, you don't get stars actually


00:17:01.040 --> 00:17:02.470
colliding because there's so much space


00:17:02.480 --> 00:17:04.630
between the stars, but what you get is


00:17:04.640 --> 00:17:07.110
the effect of clouds of gas colliding


00:17:07.120 --> 00:17:10.230
and that spawns new star formation. So,


00:17:10.240 --> 00:17:12.390
uh you might get lots of hot young stars


00:17:12.400 --> 00:17:14.870
being born in a in a galaxy collision.


00:17:14.880 --> 00:17:17.110
>> All right, here's my horrible attempt at


00:17:17.120 --> 00:17:18.949
poetry. It's more of a dance than a


00:17:18.959 --> 00:17:20.470
glance. Boom.


00:17:20.480 --> 00:17:21.510
>> Oh, I like that.


00:17:21.520 --> 00:17:21.990
>> Yeah.


00:17:22.000 --> 00:17:23.990
>> Yeah, it is actually. That's exactly


00:17:24.000 --> 00:17:25.429
what it is. Yeah.


00:17:25.439 --> 00:17:27.590
>> There. There we go. All right. Hope that


00:17:27.600 --> 00:17:29.510
answered your question, Lena. Thanks for


00:17:29.520 --> 00:17:31.029
sending it in and um thanks for


00:17:31.039 --> 00:17:33.029
listening to Space Nuts, which is what


00:17:33.039 --> 00:17:34.630
you're doing right now with Andrew


00:17:34.640 --> 00:17:38.870
Dunley and Professor Fret Watson.


00:17:38.880 --> 00:17:41.029
>> We choose to go to the moon in this


00:17:41.039 --> 00:17:43.590
decade and do the other things, not


00:17:43.600 --> 00:17:45.909
because they are easy, but because they


00:17:45.919 --> 00:17:48.950
are hard. these nuts.


00:17:48.960 --> 00:17:52.549
>> And now our next question comes from


00:17:52.559 --> 00:17:54.549
Kevin and he said, "I've been listening


00:17:54.559 --> 00:17:57.270
with much learning and enjoyment to all


00:17:57.280 --> 00:17:59.510
the previous podcasts. I'm about halfway


00:17:59.520 --> 00:18:01.909
through them." So he's at around 200


00:18:01.919 --> 00:18:04.789
nearly 300, I imagine. So let's just


00:18:04.799 --> 00:18:08.230
wait for him to catch up.


00:18:08.240 --> 00:18:10.870
He says, "Uh, your your discussions of


00:18:10.880 --> 00:18:13.350
Mars and its lack of atmosphere made me


00:18:13.360 --> 00:18:16.390
wonder if perhaps what must have been an


00:18:16.400 --> 00:18:18.870
enormous eruption of Olympus Olympus


00:18:18.880 --> 00:18:21.110
Mons is what might have killed the


00:18:21.120 --> 00:18:23.750
planet or at least its atmosphere." That


00:18:23.760 --> 00:18:28.950
comes from Kevin. Uh so yeah, I I um I


00:18:28.960 --> 00:18:30.950
I'm very impressed by Olympus Mons


00:18:30.960 --> 00:18:32.870
because it is the biggest volcano in the


00:18:32.880 --> 00:18:37.190
solar system and uh it it's staggeringly


00:18:37.200 --> 00:18:41.110
huge. But uh could could a uh an Olympus


00:18:41.120 --> 00:18:43.510
Mons eruption have have stripped the


00:18:43.520 --> 00:18:46.630
atmosphere of Mars?


00:18:46.640 --> 00:18:51.350
>> Um probably not. Uh the I mean the the


00:18:51.360 --> 00:18:53.909
the eruptions of Olympus Mons would


00:18:53.919 --> 00:18:57.110
certainly have sent a lot of gas into


00:18:57.120 --> 00:19:01.190
the atmosphere. Um it it Olympus Mons


00:19:01.200 --> 00:19:03.270
has probably taken a long long time to


00:19:03.280 --> 00:19:07.590
grow. Uh it's you know it would have had


00:19:07.600 --> 00:19:09.510
uh eruptions kind of like some of the


00:19:09.520 --> 00:19:12.789
bigger volcanoes on Earth. Uh and they


00:19:12.799 --> 00:19:15.510
took a long long time. So it's not like


00:19:15.520 --> 00:19:18.630
one big explosion. Um, and that's why


00:19:18.640 --> 00:19:20.470
Olympus Mons is so high. It's because


00:19:20.480 --> 00:19:23.510
it's over a hot spot in Mars's mantle.


00:19:23.520 --> 00:19:26.150
Uh, that just keeps on pushing out


00:19:26.160 --> 00:19:27.990
material or did for a long period of


00:19:28.000 --> 00:19:29.990
time. Uh, and without the plate


00:19:30.000 --> 00:19:32.549
tectonics that carry this the surface


00:19:32.559 --> 00:19:34.789
crust over the hot spot and results in a


00:19:34.799 --> 00:19:36.390
chain of volcanoes like we see in


00:19:36.400 --> 00:19:39.590
Hawaii, uh, it all built this one big


00:19:39.600 --> 00:19:42.070
volcano. So, it's a process that took a


00:19:42.080 --> 00:19:45.270
long time and maybe it did play a role


00:19:45.280 --> 00:19:49.830
in the the changes in Mars's atmosphere.


00:19:49.840 --> 00:19:52.070
But we think the main reason why Mars


00:19:52.080 --> 00:19:55.190
lost its atmosphere is because it is a


00:19:55.200 --> 00:19:58.310
world that is too small to sustain plate


00:19:58.320 --> 00:20:00.470
tectonics. It doesn't have a magnetic


00:20:00.480 --> 00:20:03.029
field. So, the subatomic particles from


00:20:03.039 --> 00:20:04.710
the sun bombard the atmosphere


00:20:04.720 --> 00:20:06.789
continuously. And we think that's one of


00:20:06.799 --> 00:20:09.029
the main reasons why uh why it


00:20:09.039 --> 00:20:11.190
eventually lost lost its atmosphere. I


00:20:11.200 --> 00:20:12.710
mean it's not lost altogether. It's


00:20:12.720 --> 00:20:15.190
still got 6 of a percent of the earth's


00:20:15.200 --> 00:20:16.710
atmospheric pressure at the surface.


00:20:16.720 --> 00:20:19.270
That's enough for winds to blow uh and


00:20:19.280 --> 00:20:21.510
um you know to to sort of blow dust


00:20:21.520 --> 00:20:23.830
clouds onto solar panels of spacecraft


00:20:23.840 --> 00:20:26.230
and things of that sort. But it's


00:20:26.240 --> 00:20:27.990
certainly not an atmosphere that we


00:20:28.000 --> 00:20:30.149
would recognize as being similar to


00:20:30.159 --> 00:20:32.789
Earth's. So um I think I think it's a


00:20:32.799 --> 00:20:34.310
good question actually. Um, I think


00:20:34.320 --> 00:20:37.510
Olympus Mons and the neighboring


00:20:37.520 --> 00:20:39.350
volcanoes, there's there's more than one


00:20:39.360 --> 00:20:41.430
big volcano there. Olympus Mons is the


00:20:41.440 --> 00:20:43.190
biggest. They probably would have


00:20:43.200 --> 00:20:45.110
affected the atmosphere of Mars, but


00:20:45.120 --> 00:20:46.549
they're probably not the root cause


00:20:46.559 --> 00:20:48.870
while why the atmosphere drifted into


00:20:48.880 --> 00:20:49.830
space.


00:20:49.840 --> 00:20:53.350
>> Yeah, it's more likely it was because


00:20:53.360 --> 00:20:55.830
Mars just couldn't hold itself together,


00:20:55.840 --> 00:20:59.750
basically. Um, it it didn't have the uh


00:20:59.760 --> 00:21:01.669
the gravity. Um


00:21:01.679 --> 00:21:04.549
>> it's yeah it it it doesn't have the


00:21:04.559 --> 00:21:08.230
gravity uh to keep it hot enough to


00:21:08.240 --> 00:21:11.029
sustain plate tectonics or a magnetic


00:21:11.039 --> 00:21:13.350
dynamo basically which gives it a


00:21:13.360 --> 00:21:14.549
magnetic field.


00:21:14.559 --> 00:21:17.750
>> Yeah. But Olympus Mons is fascinating


00:21:17.760 --> 00:21:19.909
for a few reasons. I correct me if I'm


00:21:19.919 --> 00:21:22.789
wrong but I think right now as Mars is


00:21:22.799 --> 00:21:26.230
uh Olympus Mons summit actually peaks


00:21:26.240 --> 00:21:28.070
out of the atmosphere. Is that right?


00:21:28.080 --> 00:21:30.470
It's sticking up that high. Uh yeah, no


00:21:30.480 --> 00:21:33.029
it's certainly I mean the atmosphere is


00:21:33.039 --> 00:21:35.590
like Earth's atmosphere. It gradually


00:21:35.600 --> 00:21:38.630
disappears as you go higher. Uh but


00:21:38.640 --> 00:21:40.950
yeah, I mean effectively the summit is


00:21:40.960 --> 00:21:42.789
the pressure will be considerably lower


00:21:42.799 --> 00:21:44.950
there than it is down at the what you


00:21:44.960 --> 00:21:46.950
might call the surface of Mars.


00:21:46.960 --> 00:21:49.909
>> This is one honking big shield volcano


00:21:49.919 --> 00:21:52.390
though, isn't it? Like 21.287


00:21:52.400 --> 00:21:56.870
kilometers in height. Uh 13.2 2 milesi


00:21:56.880 --> 00:21:59.270
or 69,840


00:21:59.280 --> 00:22:01.029
ft.


00:22:01.039 --> 00:22:02.630
Uh, someone's going to climb that one


00:22:02.640 --> 00:22:05.750
day and um, stick a flag in it. Uh, it's


00:22:05.760 --> 00:22:07.430
2 and a half times the elevation of


00:22:07.440 --> 00:22:09.350
Mount Everest. And and this is something


00:22:09.360 --> 00:22:11.190
about Mars that astounds me. It's a


00:22:11.200 --> 00:22:13.990
smaller planet, but all its features


00:22:14.000 --> 00:22:16.630
geographically just make ours look like


00:22:16.640 --> 00:22:20.230
tiddlywinks. Um, and it's its span is


00:22:20.240 --> 00:22:22.310
600 kilometers.


00:22:22.320 --> 00:22:24.230
>> 600 kilometers wide.


00:22:24.240 --> 00:22:26.470
>> Yep. That's that's extra. I just can't


00:22:26.480 --> 00:22:28.789
imagine it. I' I'd love to be able to


00:22:28.799 --> 00:22:30.870
stand there and have a look in my last


00:22:30.880 --> 00:22:32.789
five seconds of life because I didn't


00:22:32.799 --> 00:22:35.909
take my breathing apparatus. But um it


00:22:35.919 --> 00:22:38.710
it is it is an amazing world.


00:22:38.720 --> 00:22:40.710
>> It's got um cliffs as well around its


00:22:40.720 --> 00:22:42.789
base which are pretty spectacular. I


00:22:42.799 --> 00:22:45.270
think they're kilometers high as well.


00:22:45.280 --> 00:22:48.390
So, you know, it's Yes. Quite quite


00:22:48.400 --> 00:22:51.110
quite a an extraordinary world.


00:22:51.120 --> 00:22:53.990
>> Yeah. Well, the caldera itself is 50


00:22:54.000 --> 00:22:55.590
miles across


00:22:55.600 --> 00:22:57.830
>> and you compare that to Kilaweo which is


00:22:57.840 --> 00:23:01.350
like a couple of miles across. It's it's


00:23:01.360 --> 00:23:04.070
amazing. Um, no, I love that question


00:23:04.080 --> 00:23:06.230
and um, yeah, good thinking, but uh,


00:23:06.240 --> 00:23:07.750
probably not. And it it it sort of


00:23:07.760 --> 00:23:10.230
brings back the same argument on Earth


00:23:10.240 --> 00:23:11.990
that people say our global warming is


00:23:12.000 --> 00:23:14.390
caused by volcanoes and cows. It's got


00:23:14.400 --> 00:23:15.830
nothing to do with, you know, the


00:23:15.840 --> 00:23:17.270
billions of cars that we're driving


00:23:17.280 --> 00:23:19.350
around every day. But, uh, I think


00:23:19.360 --> 00:23:23.909
they've proven that's just not the case


00:23:23.919 --> 00:23:26.789
as far as I'm aware. Um, thanks for your


00:23:26.799 --> 00:23:28.549
question, Kevin. Lovely to hear from


00:23:28.559 --> 00:23:32.470
you. Our final question comes from Yuki.


00:23:32.480 --> 00:23:35.110
Hi, I'm Yuki. I am 5 years old and I


00:23:35.120 --> 00:23:37.990
live in Canra. Uh, we listen to your


00:23:38.000 --> 00:23:39.909
podcast nearly every day. My question


00:23:39.919 --> 00:23:43.270
is, why is hydrogen the only element


00:23:43.280 --> 00:23:45.990
that isn't made in stars? Why was


00:23:46.000 --> 00:23:48.549
hydrogen the only element around just


00:23:48.559 --> 00:23:52.950
after the big bang and not others?


00:23:52.960 --> 00:23:56.549
>> Yeah, that's a great question. Uh and uh


00:23:56.559 --> 00:23:59.750
congratulations to Yuki on being able to


00:23:59.760 --> 00:24:01.350
even think of a question like that at


00:24:01.360 --> 00:24:02.870
the age of five because I certainly


00:24:02.880 --> 00:24:03.830
wouldn't have been able.


00:24:03.840 --> 00:24:05.510
>> No, I wouldn't either. I was still


00:24:05.520 --> 00:24:08.630
trying to fix the wheel on my Tonka toy.


00:24:08.640 --> 00:24:11.029
>> Yes, that's right. think I was at that


00:24:11.039 --> 00:24:15.430
level. And the look the the bottom line


00:24:15.440 --> 00:24:17.669
is that hydrogen


00:24:17.679 --> 00:24:20.630
uh it was created in the aftermath of


00:24:20.640 --> 00:24:22.789
the big bang. I think sort of 3 minutes


00:24:22.799 --> 00:24:25.510
after the big bang, the temperature had


00:24:25.520 --> 00:24:27.669
cooled enough that you could start to


00:24:27.679 --> 00:24:29.110
form atoms.


00:24:29.120 --> 00:24:33.990
>> Um and the the atom that was was


00:24:34.000 --> 00:24:35.909
produced was the simplest. It's one


00:24:35.919 --> 00:24:38.950
proton. uh it's the simplest atomic


00:24:38.960 --> 00:24:43.190
nucleus. And so uh that was what


00:24:43.200 --> 00:24:47.269
basically condensed out of the uh of the


00:24:47.279 --> 00:24:50.630
of the aftermath of the big bang as as


00:24:50.640 --> 00:24:54.310
energy became matter. You got protons


00:24:54.320 --> 00:24:58.870
forming and hydrogen is protons. Uh in


00:24:58.880 --> 00:25:03.350
fact in that same period uh you also got


00:25:03.360 --> 00:25:05.750
the start of the process that does


00:25:05.760 --> 00:25:08.549
produce other elements in stars what we


00:25:08.559 --> 00:25:12.149
call nucleioynthesis where the nuclei of


00:25:12.159 --> 00:25:14.230
atoms the centers of the atoms stick


00:25:14.240 --> 00:25:17.750
together um and it did that process did


00:25:17.760 --> 00:25:19.430
start so I think I can't remember the


00:25:19.440 --> 00:25:21.269
percentage it's something like 20% I


00:25:21.279 --> 00:25:23.350
think of the aftermath of the big bang


00:25:23.360 --> 00:25:27.909
is helium which is the next most complex


00:25:27.919 --> 00:25:31.350
at atomic nucleus um and formed by


00:25:31.360 --> 00:25:34.710
hydrogen atoms coming together. But then


00:25:34.720 --> 00:25:36.630
uh the temperature dropped far enough


00:25:36.640 --> 00:25:40.470
that you didn't get the extension of


00:25:40.480 --> 00:25:44.390
that process into the formation of other


00:25:44.400 --> 00:25:49.830
atoms. Um, so it basically had to wait


00:25:49.840 --> 00:25:53.430
until stars started to form because of


00:25:53.440 --> 00:25:55.190
the gravitational pull of these clouds


00:25:55.200 --> 00:25:58.630
of hydrogen together. Uh, that raised


00:25:58.640 --> 00:26:01.669
the temperature again enough to start


00:26:01.679 --> 00:26:05.269
forming other elements. Um, and so that


00:26:05.279 --> 00:26:07.110
that's basically what it's all about.


00:26:07.120 --> 00:26:09.750
It's just the simplest of atoms is the


00:26:09.760 --> 00:26:11.830
hydrogen atom. That is why that was


00:26:11.840 --> 00:26:14.710
created. uh and and you know we nearly


00:26:14.720 --> 00:26:17.510
got more more uh elements being created


00:26:17.520 --> 00:26:21.269
in the big bang uh but only uh helium


00:26:21.279 --> 00:26:23.350
actually there's a bit of lithium and


00:26:23.360 --> 00:26:27.029
other stuff as well tiny amounts uh of


00:26:27.039 --> 00:26:31.350
of other nuclei but um it it it's true


00:26:31.360 --> 00:26:33.990
to say that the star formation star


00:26:34.000 --> 00:26:37.029
formation and the interiors of stars is


00:26:37.039 --> 00:26:39.990
what led to the huge array of elements


00:26:40.000 --> 00:26:41.750
that we see now all the elements of the


00:26:41.760 --> 00:26:43.190
periodic table.


00:26:43.200 --> 00:26:44.789
>> Thanks Ricky. That's a fantastic


00:26:44.799 --> 00:26:45.190
question.


00:26:45.200 --> 00:26:45.990
>> It is.


00:26:46.000 --> 00:26:47.909
>> When when you look at the the the list


00:26:47.919 --> 00:26:51.269
of the top 10 gases in the universe by


00:26:51.279 --> 00:26:53.510
order of concentration,


00:26:53.520 --> 00:26:55.590
hydrogen is far and away the most


00:26:55.600 --> 00:26:59.990
dominant with um 74 to 75% of what they


00:27:00.000 --> 00:27:02.149
describe as barionic mass.


00:27:02.159 --> 00:27:06.149
>> Helium at 24 to 25%. Which leaves almost


00:27:06.159 --> 00:27:08.870
no room for anything else. Oxygen is


00:27:08.880 --> 00:27:10.950
less than 1%, carbon less than half a


00:27:10.960 --> 00:27:14.710
percent, neon less than 0.1. Um, and


00:27:14.720 --> 00:27:17.029
then it just dwindles away. At number


00:27:17.039 --> 00:27:21.510
10, you got sulfur at 0.00 uh 044%


00:27:21.520 --> 00:27:23.110
concentration.


00:27:23.120 --> 00:27:24.789
Um,


00:27:24.799 --> 00:27:27.750
it it it's staggering numbers when you


00:27:27.760 --> 00:27:28.789
really


00:27:28.799 --> 00:27:30.149
>> Yeah. So,


00:27:30.159 --> 00:27:31.190
>> go down the list.


00:27:31.200 --> 00:27:33.350
>> The bottom line is that the the big bang


00:27:33.360 --> 00:27:36.789
hydrogen is still around. In fact, it it


00:27:36.799 --> 00:27:39.029
makes up quite a large percentage of the


00:27:39.039 --> 00:27:41.830
atoms in your body as well.


00:27:41.840 --> 00:27:44.390
>> Yeah. Yeah. I um Well, it's everywhere,


00:27:44.400 --> 00:27:47.029
isn't it? Um and


00:27:47.039 --> 00:27:49.430
>> that that's the bottom line. And and the


00:27:49.440 --> 00:27:51.909
the way the Big Bang happened and


00:27:51.919 --> 00:27:54.230
everything that went on afterwards, um


00:27:54.240 --> 00:27:56.310
you know, if one smidgy little thing


00:27:56.320 --> 00:27:57.990
didn't happen, we probably wouldn't be


00:27:58.000 --> 00:27:58.789
here.


00:27:58.799 --> 00:27:59.190
>> Yeah,


00:27:59.200 --> 00:28:02.230
>> that's right. H it's a scary thought but


00:28:02.240 --> 00:28:04.710
then again uh there's so much we don't


00:28:04.720 --> 00:28:05.990
know.


00:28:06.000 --> 00:28:08.470
>> People believe in believe in multiverses


00:28:08.480 --> 00:28:11.269
because um they say you know the


00:28:11.279 --> 00:28:14.230
conditions are exactly right for life to


00:28:14.240 --> 00:28:16.149
form in our universe and they might not


00:28:16.159 --> 00:28:17.110
have be.


00:28:17.120 --> 00:28:17.430
>> Yeah.


00:28:17.440 --> 00:28:18.789
>> So maybe there are lots of other


00:28:18.799 --> 00:28:22.549
universes where life didn't form.


00:28:22.559 --> 00:28:24.389
>> Well yeah that the the mathematics


00:28:24.399 --> 00:28:26.470
supports the theory, doesn't it?


00:28:26.480 --> 00:28:28.310
>> Yeah.


00:28:28.320 --> 00:28:31.269
>> Oh gosh. It's the brain hurting part of


00:28:31.279 --> 00:28:33.430
the show just happened. So anyway, um


00:28:33.440 --> 00:28:34.950
yeah,


00:28:34.960 --> 00:28:36.630
it it just keeps us thinking and it


00:28:36.640 --> 00:28:38.310
keeps us looking for answers and that's


00:28:38.320 --> 00:28:40.389
what it's all about. Yuki, great to hear


00:28:40.399 --> 00:28:43.590
from you and hope all is well in Canra.


00:28:43.600 --> 00:28:45.430
And a reminder, if you would like to


00:28:45.440 --> 00:28:47.909
send us questions, uh we welcome them


00:28:47.919 --> 00:28:49.430
with open arms. You can send them


00:28:49.440 --> 00:28:52.470
through our website spacenuts.io


00:28:52.480 --> 00:28:54.710
and just click on the ask me anything


00:28:54.720 --> 00:28:58.149
link at the top. it says AMA and we will


00:28:58.159 --> 00:29:00.070
do our best. Don't forget to tell us who


00:29:00.080 --> 00:29:03.269
you are and where you're from and we


00:29:03.279 --> 00:29:05.830
will um put your question on if we


00:29:05.840 --> 00:29:07.269
haven't had it before. And even if we


00:29:07.279 --> 00:29:09.990
have, we might uh revisit them. We do


00:29:10.000 --> 00:29:12.149
that from time to time. Uh keep them


00:29:12.159 --> 00:29:14.389
coming. And if you haven't asked a


00:29:14.399 --> 00:29:15.590
question before and you've always wanted


00:29:15.600 --> 00:29:17.990
to, please send it in. We we'd love to


00:29:18.000 --> 00:29:20.950
hear from you. And um we're just about


00:29:20.960 --> 00:29:23.190
done. Fred, thank you very much.


00:29:23.200 --> 00:29:25.590
>> Uh great pleasure, Andrew. always good


00:29:25.600 --> 00:29:28.230
and uh hopefully we'll chat again soon.


00:29:28.240 --> 00:29:30.470
>> I hope so. That'll be good. Professor


00:29:30.480 --> 00:29:32.149
Fred Watson, astronomer at large and


00:29:32.159 --> 00:29:34.230
thanks to Hugh in the studio who didn't


00:29:34.240 --> 00:29:35.990
have a hydrogen problem, but he did have


00:29:36.000 --> 00:29:38.070
a methane problem, but he'll be out of


00:29:38.080 --> 00:29:39.990
emergency surgery very, very soon,


00:29:40.000 --> 00:29:41.350
hopefully for next week's episode. And


00:29:41.360 --> 00:29:42.950
for me, Andrew Dunley, thanks for your


00:29:42.960 --> 00:29:44.950
company. Catch you on the next episode


00:29:44.960 --> 00:29:47.110
of Space Nuts. Bye-bye.


00:29:47.120 --> 00:29:49.510
>> Space Nuts. You'll be listening to the


00:29:49.520 --> 00:29:52.470
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00:29:52.480 --> 00:29:55.430
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00:29:58.159 --> 00:30:00.549
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