May 27, 2021

Heavy Metal

Heavy Metal

Astronomy, Science, Space, and Stuff.
Space Nuts Episode 254 with Professor Fred Watson & Andrew Dunkley
●Heavy Metals discovered in vapour trails of com...


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Astronomy, Science, Space, and Stuff.

Space Nuts Episode 254 with Professor Fred Watson & Andrew Dunkley

●    Heavy Metals discovered in vapor trails of comets

●    Where we live…in the scheme of things it’s pretty ordinary and boring…and we like it like that.

●    Questions – from Tim in Lismore (NSW, Australia) who asks what would happen if he dipped his toe into a black hole? And Paul in Toowoomba (Queensland, Australia) with questions about magnetism and tractor beams. Fred has answers for both.

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Transcript

Space Nuts 254 AI Transcript

[00:00:00] Fred: [00:00:00] 15 seconds. Guidance is internal and ignition sequence

two nuts as the magic word.

Andrew: [00:00:15] It feels good. Hello, once again, thank you for joining us. On yet another episode of the space NATS podcast, we thought you'd be fed up by now, but no, you keep asking for more. So we keep delivering episode 254. Good grief. I can't believe we've talked for near 254 hours about all of this stuff, but people.

Find it fascinating. I hope you do too. And thank you for joining us. My name's Andrew Dunkley, by the way, your host and joining me again is professor Fred Watson astronomer at large.

Fred: [00:00:47] Hello, Fred. Hi, Andrew. How are you doing? You're looking Hale and hearty if I may say so.

Andrew: [00:00:54] Oh, thank you, sir. You're looking wonderful yourself.

Fred: [00:00:56] Oh, jolly good. I've

Andrew: [00:00:59] had a [00:01:00] pretty good week. I suppose. I'm I'm getting my first COVID vaccine injection on Monday.

Fred: [00:01:08] Oh, yeah, that could be interesting. Oh, you'll enjoy it. It's a thrill I'd mind. Four weeks ago, five weeks ago.

Andrew: [00:01:19] I'm thinking that I need to do it and then talk about it on the radio because of the negative publicity surrounding some of the effects that have bled in the, um, Highlighted around the world and you talked to the doctors and the nurses, and they'll, they'll tell you, look that, you know, those things are happening in very, very small quantities and the odds of anything going pear shaped are one in a million.

So, you know, I'm thinking I need to do this and yeah. Yeah. And I'm thinking I need to get mine and, and get on the radio and say, okay, I did it. And this is, you know, this is the story, but, uh, we will, um, That'll be next week. If I'm [00:02:00] not here next week, you'll know that my arms to sorta lift up.

Fred: [00:02:07] You'll be all right.

Yeah. I didn't have any, any aftereffects at all with mine. I had, I had more, yeah, well more with the flu job that I had, which gave me very, very slight flu symptoms. You, I know you, you come down really badly with the flu when you have a flu jab, but AstraZeneca did nothing I have in the past.

Andrew: [00:02:27] Great. Yeah, well, I had a flu injection two and a half weeks ago and no side effects at all.

It was just a, just a bit of a sore arm for about a day, but nothing, nothing at all. But, uh, yeah, after getting the flu full on in 2018, I am religious about getting my flu vaccine now. Uh, because I don't want to ever go through that again. It was horrible. Okie dokie. Uh, it's time to, um, look at what we're going to be talking about this week.

We're going to be talking about COVID 19, the [00:03:00] AstraZeneca injection. Hang on. We've already done that. We're going to talk about heavy metals in the vapor of comets. This is a new discovery. Um, I'm thinking, um, Metallica was in there, um, banging away. And maybe a couple of other heavy metal bands

Fred: [00:03:18] of the era bill Haley and his comments as well from the 1950s.

They'd be in there. They're not heavy metal, but now oh yeah, for sure.

Andrew: [00:03:27] Yeah. And we're going to talk about where we live, because I'm, I'm sorry to break this to you, but the journalist in me must report the facts. We live in a really ordinary place. I mean, in the scheme of things, It is as boring as bat poo, uh, which is, you know, maybe a good thing we'll find out.

Uh, we've got questions as well from Tim and Lismore, who wants to know about dipping his toe in a black hole? Not a good idea team. Uh, also the stability of our solar system. [00:04:00] Why is it? So because it's

Fred: [00:04:02] ordinary

Andrew: [00:04:03] it's, that's why

Fred: [00:04:05] and pull from, to Toowoomba. He's

Andrew: [00:04:08] asking questions about magnets, magnetism, and tractor beams, all that to come on this episode of space nuts, which we're planning to knock over in probably three or four minutes.

Now, Fred, let's start with heavy metals in comet vapor. This is just been discovered in I'm guessing there's a paper or at least some form of study. That's come up with this interesting discovery, this interesting

Fred: [00:04:34] find. Indeed. Yeah. Um, there is, there is paper and, um, lots of press about it as well, because it's a really interesting result.

And I should tell you that, um, these studies, uh, use the telescopes of the European Southern observatory down there in Chile, uh, which, um, are pretty well the, the best equipped, uh, large telescopes in the Southern hemisphere. There are. [00:05:00] Few other ones down there, which are pretty damn good as well. But, uh, the, the four telescopes of the very large telescope there they're cracking.

Good. And so they were used to make these observations. And what's interesting about this is, uh, but by heavy metals, actually, we should, we should. Perhaps just define that for a minute, Andrew, because astronomy is that idea. I've got a, I've got a very funny view of what constitutes a metal and a metal in astronomy is anything other than hydrogen and helium.

So oxygen is a metal calcium's about right? Yeah. Um, it's it's, it's always been like that, I guess, probably since the start of astronomical spectroscopy, the idea of breaking up the light from stars and, um, finding out what signatures of elements you can get in there. But yeah, the, the metal, is there anything.

Uh, heavier than hydrogen or helium. Uh, so when you talk about heavy metals, you're really talking about [00:06:00] what you and I would call metals in normal life. And in particular iron and nickel and iron is the communist, uh, metal in the, uh, in the, in the universe. Uh, in fact, one of the communist elements and it's because it's a, it's a by-product of.

Uh, of the nuclear processes that go on inside stars when they're in their normal adult life. So I, and it's being created. Uh, towards the end of the life of this star, actually, anyway, th th th the bottom line is, um, uh, I, in his common Nicholas common. Now, there, there is an interesting little factoid about this, though, and that is that we find, for example, in the core of the earth, It's an iron nickel core and the iron usually outweighs the nickel when you find it in, in nature and it like metallic asteroids or, or the core of a planet, it's usually 10 times more iron than nickel, uh, which is understandable.

Cause more readily produced inside [00:07:00] stars. But in this story, Uh, we find that in these comments, uh, if you've got more or less equal proportions and that is unexpected, uh, that there are equal proportions of iron and nickel in the comments. Now we've known, uh, for a long time that comments must have this sort of stuff in the material.

Remember become it. So I see bodies with lots of dust embedded in the eyes, and that dust includes heavy metals. And the temperatures of these things are typically called her a minus a hundred degrees Celsius. So they're very, very cold and the metal is normally, um, remain very much as grains of dust, but basically not, not anything that's vapor, but that's the surprise with these observations.

Um, and it comes from groups in Poland and Melbourne, I think. Sorry, Poland of Belgium. I think the, um, Main centers where the astronomers [00:08:00] who worked on this, uh, come from, um, there are two studies actually. Um, in fact, let me get it right. The first study is the, uh, the, the solar system comets and that's the Belgian study.

The second one is our old friend comment Boris off, uh, which has been looked at by a group from Poland. Um, Boris that's the one. Yeah. That, um, both of them have found this unexpected result, that the metals turn up in the vapor of the comment, the stuff that's ejected from the comment when it gets near the sun.

So that material vaporizes now, normally these, these elements they're vaporize. At very high temperatures, um, uh, 700 degrees Celsius or thereabouts. And we're talking here about minus a hundred, so what's going on? Um, and I should, I should just, um, clarify there that when I say vaporize, I mean they [00:09:00] sublimate and sublimation is the process when a solid turns directly to a gas, which happens a lot in astronomy because it's what you, what, what elements do in a vacuum, basically go straight from Solidere.

To gas. It's why on the surface of Mars, which is not a vacuum, but not quite ice doesn't turn into water. It just turns straight into water vapor. Uh, so, uh, that's the process sublimation, but the mystery. Yeah. Why, why is it that at these ultra low temperatures, uh, these metals are turning into vapors and I think as I understand the research.

Um, I can quote actually from the paper and you'll see the problem. Uh, the paper says Unbound nickel atoms seem to originate from the photo dissociation of short-lived nickel content, a short-lived nickel containing molecule that sublimate set, not low temperatures, or is otherwise released with major volatile compounds.

Did you get all that Andrew? Cause that's the answer. [00:10:00] Okay. What it means is, um, What it means is that, um, uh, the, the, the key word there is footed association. It's the radiation of the sun hitting these things. And it's, uh, it's a nickel containing molecule. Uh, and basically the radiation from the sun shoots out the, uh, the nickel atoms.

And the same is probably true with the iron. I think that's the story that it's all about. The sun's radiation acting directly on these atoms. You asked me

Andrew: [00:10:31] Fred. If you'd asked me to guess before you told me the answer, I would have said I'm, I'm going to imagine it's something to do with this hitting the comment you

Fred: [00:10:41] see is what I want to say.

It should be an astronomer, Andrew, cause you, well, you've been now mixed up with them, but yeah, absolutely. Right. Um, I'll be a journalist. We don't have to think much. I think that's not quite true, but nevermind. Um, yeah, it's, [00:11:00] it's uh, I don't think you think at all. No, no. I never said that. Um, journalists, I think I have to think now an awful lot and um, a lot of them, these forensic journalists and, you know, investigative journalists, they're doing a fantastic job.

Uncovering all kinds of, yeah, it would be make many friends. No, but you don't. I bet he knows. Good job. You've got me. Isn't it really? Yes. Going back to that, you were right on the money it's to do with the sun's radiation. To be honest, I would have guessed something similar, but I think I would have got it wrong.

I think you've got it right. I would have thought, oh, it's the subatomic particles in the solar wind that do this. And it doesn't look as though that's what it is. It's the, it's actually the radiation, the light radiation from the sun. So there you go.

Andrew: [00:11:47] Well, when I, when I say, I think it's got something to do with the sun, that's a pretty broad answer.

Fred: [00:11:54] Yes.

Andrew: [00:11:55] That could mean anything. So

Fred: [00:11:56] that's a journalist at work. Yeah, that's right. Make it broad. [00:12:00] So, um, I guess the, the, the nice twisted, this is the Polish work that, um, as looked at comic Boris off the first interstellar comment that we've. Ever observed and found that he's got very, very similar properties to solar system comments.

And in fact, some work that we talked about about probably a month or so ago revealed that, um, it, it seems to be like a solar system comment in every way, except it's never been near a star. So it's a pristine, um, sample of the, of the raw material of stars and planets really interesting that it's, uh, an IC remnant of the, of the gas and dust cloud that, that solar system, wherever it was, was formed in.

Um, and this work, you know, kind of underlines that. Yeah,

Andrew: [00:12:46] I'm not surprised the Polish looked at Barra salve. It's a very Eastern book.

Fred: [00:12:52] That's right.

Andrew: [00:12:53] I wonder if that's why they chose to look at it. Well, just the opportunity presented itself, I imagine. [00:13:00] And I don't suppose we'll ever, can we ever figure out exactly where it came

Fred: [00:13:03] from?

By herself. No, it's kind of a bit of a mystery. Really. You can see what direction it came from, but you don't know how long it's been traveling in that direction. Um, and like, um, our old friend , which came from the direction of the bright star vaguer, uh, but. When, you know, when Maura was where Vega is Vega wasn't there.

It was somewhere else because Vegas moving as well. The, the comments moving in Vegas anyway. So we'll probably never know where they came from, but it's this.

Andrew: [00:13:36] Go ahead. Same difficulty you face with time travel, because you've got to figure out where something's going to be when you get otherwise you'll end up in the vacuum of space.

Fred: [00:13:46] Yeah. They'll tell that that's exactly where you'd end up feeling very uncomfortable. Probably. It was the age old question. My new book, I got it all figured out. Okay, good. I actually had to

Andrew: [00:13:58] rewrite a section and [00:14:00] because, uh, I, I put all the data down about the time travel anomaly, and then realized, yeah, some, one of our listeners actually said, uh, you know, uh, how do you avoid ending up in the vacuum of space?

And you were explaining the third element to, uh, to time travel, that would be required. And I went, oh, I better write that in typing away. Got that. Got that sorted out. Yeah.

Fred: [00:14:22] It is.

Andrew: [00:14:23] Yeah, it is interesting that a, these discoveries have been made on, on two separate and very, very different comments and therefore stands to reason that this is not uncommon at all.

Fred: [00:14:35] Uh, th that's that's right. That, uh, you know, this actually is a lovely segue to our next story in the next segment, Andrew, that we're pretty ordinary. The solar system is probably very, very typical in many ways, although it's different in some ways we

Andrew: [00:14:52] all right, we will get onto that in a moment, but you are listening to the space NATS podcast with Andrew Dunkley and Fred [00:15:00] Watson.

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Just visit the support page now. Back to the show space nuts. Now, Fred, uh, patron numbers are increasing, which is fantastic because we have been appealing for people who wish to voluntarily, uh, become patrons of the space, not space nights, podcasts that you can log onto our website space, NATS [00:17:00] podcast.com, click on the support or that link and find out how you can be a supporter of space.

And that's whether that's through a regular monthly, Payment through Patrion or super cast or a one-off donation, or maybe just spending a couple of dollars through the space and that's shop totally up to you. Totally voluntary. You don't have to do any of that. You can just tune in and listen every week if you so desire.

But the goal is for us to get, um, patron numbers up to the point where it's self-sustaining and we, uh, Rely less on third parties. Uh, although we thank them for their support too. I mean, people are coming to us pretty regularly now wanting to support the space and that's podcasts. And we so appreciate that.

Uh, and, uh, yeah, we've got some wonderful collaborations in development at the moment and we've got some new, yeah. Ideas we're working on just a few things. We think we'll value add to the space and that's podcast. Uh, these are, what, what was the, what's the term you used? In development. [00:18:00] So we will, um, we will tell you more about those as they get closer, but thank you to all our patrons, all the people who put their money into the podcast to keep us alive and kicking and to make sure the batteries don't run out on, um, Fred's uh, machine that he has to turn on every night when he goes to bed.

Fred: [00:18:19] Uh, and, uh, also,

Andrew: [00:18:22] also thank you to our S uh, space out YouTube followers who are numbering 1.7, 2000. Now that's pretty,

Fred: [00:18:31] just makes it sound like a lot,

Andrew: [00:18:33] but yeah. Yeah. We've got 1,720 yard. And they are all odd because there's space, that's LA listeners or viewers on YouTube. Why you put up with our faces? I do not know, but we thank you for that.

All right, Fred, let's go from the extraordinary to the ordinary. And that is where we live in the universe. It's apparently not that flash when it comes down to it. It's, it's the [00:19:00] ghetto of the universe.

Fred: [00:19:02] It's um, it's not that bad. Yeah. I mean, you're using the. The ordinary word ordinary and it's Australian context, which means bloody awful.

Doesn't it?

Andrew: [00:19:15] I should clear that up. Yes. In Australia when we refer to something as ordinary, it, it means it's absolutely.

Fred: [00:19:20] But, um, yeah, the, um, But ordinary. Uh, but, uh, so, uh, perhaps, um, regular or common or something like that is a better word for what I'm going to talk about, which comes from work done by colleagues, uh, here at the university of Sydney, uh, here in Australia.

And once again, they've used the. Fantastic facilities of the European Southern observatory. It's a big plug for the ISA Lieutenant today. Um, but yeah, this is a really nice story. And actually it's got links with them, the work that I've been involved with with the, the rave survey and, um, the Gullah survey of, uh, stars [00:20:00] in our galaxy, uh, which, um, No we've talked about before, so I won't talk about it again, but it's, it's a, it's a topic, uh, investigating a topic called galactic archeology, which is how galaxies are put together and what, you know, what you can learn by looking at the constituents.

So two of my colleagues, uh, in the rave survey, uh, many years ago, discovered that our galaxy has not just one but two disks. Uh, now when we think of galaxies, we usually imagine these lovely spiral structures and our galaxy would look like that. If we could see it from the outside, um, with that being one component and another.

Being a much more rarefied. Halo is very Cleese distributed around it, of all stars in globular clusters. And that's the main constituents of galaxies. Plus the, the, the, um, the nucleus in the middle of the central core. But, uh, these colleagues of mine, uh, back in [00:21:00] the. Probably the nineties. I think this was, they discovered that the disc is not just a single disc.

It's got two components, uh, which they, uh, named, uh, the thin disc and the thick disc. Really good names, uh, because that's. Kind of what they're like. So the thin desk, and that's what you see when you look at the Milky way. Seeing the disc of our galaxy, it's about a thousand light years thick. Um, and it's the sort of central part, the thin disc is.

It's sort of envelops that it's about the same diameter, but thicker several thousand light years thick, uh, and, and much less dense, you know, it's a much more, there are far fewer stars in the thick disc, and this was the key thing, and this is really what distinguishes them. And it goes back to what we were just talking about, about, um, metals, heavy metals, because the thin disc.

Uh, where the sun is [00:22:00] located, uh, where, which is the Milky way that we see that's rich in these heavy, heavy metals that, that the heavier constituents, the iron, the nickel, all of these things that tell us that we're looking at a population of stars, which are relatively young. And that's because they've been formed from a very rich soup of.

Uh, gas, uh, the interstellar gas, which has been enriched by previous generations of stars, if I can put it that way. So our Milky way stars are that they're kind of like the sun that they've got the composition of the sun, whereas the thick disc stars. Uh, much more ancient, uh, and that comes about because you can tell that they've got far fewer of these metals in their spectrum.

Uh, so the Spectrum's much more like primitive stars. Does that existed? Uh, hundreds of, uh, sorry. Tens of, probably tens of no, let me get it right. Hundreds of millions, [00:23:00] uh, tens of billions. I've got, I keep mixing up millions of me. Billions, Andrew it's. Okay. Several billion years ago, let me put it that way.

Right. Um, so th th th that's, uh, time in the past, when the stars that were shining then had fewer of these heavy metals in their spectrum, because they hadn't been generated yet. They haven't been made by that those generations of stars. So the thin disc and the thick disc, uh, separate, uh, they're distinct in the sense that the thick disc is an older.

Structure. So when scientists tried to build models of how you would, you might form a thin disc and a thick disc with these properties, uh, they run into trouble. And the only way that you could get this structure, uh, was if you had. Quite specific, uh, events where you have a medium-sized [00:24:00] galaxy in collision with hours, something like 9 billion years ago.

And that is a process that's pretty rare. We know that galaxies eat up other smaller galaxies, but big galaxies colliding is a bit rarer. And so the suggestion was that our galaxy, it was unusual because it had had this ref. Collision, uh, 9 billion or so years ago. So, you know, that's, um, uh, was one of the reasons why we thought our galaxy wasn't pretty Henri, that it was maybe quite unusual and ma maybe richer in these metals than other galaxies.

And of course that plays into things like the origin of life and all of those issues, how much carbon you've got and things like that. So what these scientists have done is looked at. Other galaxies that are similar in appearance to the Milky way, our own galaxy using an instrument on the very large telescope down there in Chile.

And may [00:25:00] measure the spectra and they're found at least one which rejoices in the name, uh, UGC 10, seven 38. Um, it's about, uh, about a third of a billion light years away. So 320 million light years. And the nice thing about that galaxy is we're seeing it at John. So you're seeing it from the side and that means that you can actually look.

Uh, the thin and thick disc star separately. And that's what they did. And guess what they found. It's just like, oh, um, um, I'm quoting, cause there's a conversation article on this, which is well worth looking at it's called Stella secrets of a distant galaxy suggests our Milky way. Isn't so special after all.

And what the authors say is we found, and they're talking about UGC 10th, seven 38. We found metal, rich magnesium pore stars concentrated in a thin [00:26:00] disc along the Gullah galaxy center with a distinct group of metal, poor magnesium, rich stars above and below this in the thick this region, this distant galaxy is remarkably similar to our own, which in turn means there's probably nothing.

That remarkable. That's remarkable about the Milky way after all. I just discovered a typo in the, oh no, it's not a typo. There's nothing that remarkable about the Milky way after all, it should read it properly. I'm sorry. Chaps. If you're listening, uh, the, the, the, the, the issue, I didn't mention of the magnesium rich and magnesium poor, that the, that the.

Um, thick, thin disc stars and magnesium poor, the thick, this stars unusually and magnesium rich. And this comes about because of the way these materials, these elements are formed over generations of stars. It's the central pillar of the study of galactic archeology is looking at these different elements and seeing how they they're spread throughout the spectrum of the, you know, how, how much there is of them in the [00:27:00] spectrum.

So, yeah, the conclusion is where maybe not that unusual.

Andrew: [00:27:05] Yes. So rather than being boring and uninteresting, it's just, we might be more common than not.

Fred: [00:27:15] That's right. Um, if I can just go on and read, read a bit more of the conversation article, which is, um, you know, by the authors I've, I've mentioned from Sydney university, our discovery has several, several implications.

First. It suggests. The disc features in the Milky way might be the result of a standard formation path that all galaxies follow. And this is backed up by the identification of similar structures in non Milky way, light galaxies, and second, the fact that our galaxy is relatively normal. Is extremely exciting.

It implies the Milky way can act as a blueprint or template for galaxy formation. Um, means our home galaxy could hold the key to unlocking the cosmic history of the entire universe. And finally, I'm being a [00:28:00] little speculative here. The Milky is the only galaxy that we know contains life. Um, yeah.

Research has suggesting, I mentioned that. Yeah, there you go. Um, it basically, it's saying that, you know, we're a home for life. Maybe other galaxies are too.

Andrew: [00:28:16] Well, it stands to reason, doesn't it? And certainly something you can't dismiss. Uh, I know people who absolutely Natalie believe in advanced civilizations beyond earth and maybe so whether or not we'll ever be able to communicate or contact.

Uh, them or find them, uh, remains to be seen. Uh, some analysis of exoplanets may reveal the potential for civilized beings. But at this point we have evidence of one planet in the entire universe that harbors life. And that's a, I don't know where it is, but anyway, it exists. Um, now the other question I have is with the ordinariness of our.

Um, galaxy will that [00:29:00] change in a few billion years when we merged with Andromeda? Because I'll have to rewrite this

Fred: [00:29:06] paper. They will four and a half billion years down the track. Yeah. Because our galaxy, what will happen, um, is first of all, probably most of the stars will miss each other. So there won't be direct collisions, but, um, both Andromeda and.

And the Milky way, a pretty rich in hydrogen, which is the raw material of stars. And when these, this, this interaction happens, there'll be a lot of gravitational disturbance, which will form cause a lot of stars to form. There'll be a rapid burst of star formation, sort of using up the hydrogen lot of young stars, which pop off at the ends of their short lives of supernovae.

And then the end up the end product will be. Uh, uh, probably an elliptical galaxy and elliptical galaxies as their name implies. They look the shape of, uh, rugby footballs. Um, and they have very little [00:30:00] gas because it's all gone. It's all been used up by the stars in them. And

Andrew: [00:30:04] so football has had a fair bit of gas.

Fred: [00:30:08] I said different sorts of gas. Yeah. But that's right. It's it's um, um, it will change the character of our galaxy altogether. Um, you know, a lot of astronomers are already giving the end product to name, uh, which is mil kilometer, uh, because it's the Milky way. And so milk Comida is the, um, is the elliptical galaxy that will be in.

The end of it. And somebody else will write a paper on that in some of the universe. I'm sure they got that reading trashy

Andrew: [00:30:34] magazines about bread, Juliana. I reckon

Fred: [00:30:37] probably whatever that is.

I'll explain it one day. Yeah, you'll have to explain it. You really don't need to know though Fred. Okay. Money. I lost money. Oh dear. Uh,

Andrew: [00:30:53] I could get in trouble now, but, um, yes, uh, it, it, it is interesting. And the fact that, uh, we [00:31:00] are probably not ordinary is not ordinary, and that's a good thing

Fred: [00:31:05] sound to

Andrew: [00:31:07] open up the way to further analysis and maybe answering some of the questions of the universe.

Yeah,

Fred: [00:31:14] this is

Andrew: [00:31:14] the space in our space, nuts podcast. I used to know a shop owner named Mr. NUS, but that's got nothing to do with us here on the space and that's podcast, Andrew Dunkley and Fred Watson.

Space nuts. Now I did which in patrons earlier on, and, uh, I also mentioned our website, which I'm going to mention again, because why do something once when you can do it multiple times, but at our website, if you haven't visited space in that's podcast.com is the place to go to catch up on astronomy daily or the latest stories in the astronomical world.

Uh, we have a feed there. Uh, we have the shop which offers us, um, you know, Memorabilia. We've got [00:32:00] stickers. We've got mugs. We've got caps. We've got shirts. We've got all sorts of stuff. Um, oh, by the way, I don't know if I can reach because I've got my headphones in, but, um,

Fred: [00:32:08] I have got,

Andrew: [00:32:09] I'll be right

Fred: [00:32:10] back ladies and gentlemen, a headphone

Andrew: [00:32:14] back in, but I have got, um, hard copies of my

Fred: [00:32:18] book.

They got delivered the other day. That's pretty good.

Andrew: [00:32:21] Uh, I have, I got an instant request from one of our listeners. Uh, when I posted the video of me opening the box, which I did blind, I hadn't looked at themselves. They were all weird. I was going to embarrass myself, but, uh, to Marie, Claire, There's your book photograph as

Fred: [00:32:39] requested.

Very

Andrew: [00:32:41] good. So that's going to be on its way to you and thank you for, um, you know, putting, uh, your, your heart behind the podcast. We appreciate your support. She's been a great supporter of the podcast through her Instagram and Facebook pages, and she wanted the first one. So there it is ready to [00:33:00] go. That will be in the mail in one or two years.

Yeah, just letting you know now I'm just waiting a bit. Cause she's, she's, she's moving, um, to her place in Florida. So she, she doesn't want it to arrive before she gets there. Otherwise, you know, it could end up anywhere, but, um, I, I will make sure that that gets to you in a timely manner. Uh, but yeah, books are on, uh, the space nuts shop and, uh, you can also, um, um, click on all the other links and find out.

Well, you need to know about astronomy and what makes us tick because we don't know maybe, um, maybe that's something that should be studied. Uh, now Fred, let's get into some questions. The first one comes from young team. I don't know how old Tim is, but he's in Lismore in Northern new south Wales.

Promo Dude: [00:33:51] Hi Andrew.

It's Tim here from Lismore, uh, far north coast of new south Wales. God's own country. Uh, love the show I've been listening for [00:34:00] since about episode 50, uh, Manji. Wife and kids think our need to get a life, uh, a few questions, but all limit myself to two. So there's been a lot of talk recently about black holes.

And spaghettification my question is how thick is the event horizon? So. Well, now you've mentioned that recently there's been a event horizon. That's like three times the size of the solar system, but how thick is that event? Horizon line. So with Hawken radiation, it seems to indicate that it's razor thin, but like, yeah, to me, that doesn't sound right.

So like, if I did my big toe across that event, horizon line, is it going to be spaghetti? But the rest of me is going to be okay. Uh, so that's the question one. Question two is how the orbits of the planet stay stable. Surely planets and sons are expanding and moving rules, zipping around the universe.

Yeah. How we seem to be [00:35:00] relatively stable or is it just that owl? Taught my timeline so small, I would imagine everything's wizard crashing them, bumping into one another, but in, you know, everything seems to be moved along. Okay. Thanks very much.

Andrew: [00:35:16] Keep up the good work. Bye . Um, the, the whizzing and crashing and bumping into each other.

That's just standard traffic on the Pacific highway around Lismore. I imagine. Uh, and I can answer his second question. The stability of the solar system. It's because we're ordinary. That's for, um, but no, in all seriousness, um, we'll start off with this first question. If he dipped his toe into the event, horizon of a black hole, would it get spic edified?

And the rest of him would be okay. I suspect

Fred: [00:35:48] not. You're on the money there, Andrew. That's a great question. Look, I've never been asked before, how thick is the event horizon? I love it. It's great. Um, but, um, it's. [00:36:00] It doesn't actually have a thickness. So the event horizon in a sense is an illusion. Um, it's just that, um, it kind of corresponds to, uh, well, it's his fear.

Uh, but every point on that sphere is a certain distance from the black hole. Um, and that's the radius of the event horizon. Uh, but what the event horizon is, is just that point in the vicinity or that distance from the black hole in his vicinity where light can't can't escape. So it's not really to do with this spaghettification.

Point being that if you approach a black hole long before you got near the event horizon, you'd be feeling this extreme gravitational field. Uh, and you'd be spaghetti I'd already. Um, it's, uh, it's just that at the event, horizon, all these peculiar phenomenon involving photons, which are particles of light, that's where [00:37:00] they start happening.

Most notably. Uh, the fact that, uh, uh, light can't escape from the event horizon, uh, and a particle of light on the event, horizon is just whizzing, round and round it's in orbit. That's the key thing. So, um, yeah, you dipping your foot in the event horizon. It's a lovely, lovely idea. Uh that's I'm sure that's good material for your next book, Andrew.

Uh, but, um, it, it doesn't work like the event horizon is just this particular distance where light can't make it out. And so, uh, but you're already spaghetti defied. Um, so in a sense, it doesn't have a thickness. It's basically, it's a boundary between one situation and another, and I suppose an analogy to that will be the surface of the sun, uh, which is where, um, the light seems to come from when you can't see any further down.

But, but there's no, uh, you know, there's no big transition. It's just the pressure increasing as the, uh, as you get near the center of the cell. [00:38:00] That wasn't a very good analogy.

Andrew: [00:38:04] No, no. Fair enough. But I foresee a time because I see where Tim's coming from. I foresee a time when interstellar travels the thing that they're going to have to put wrong way, go back signs around all the black holes,

Fred: [00:38:19] because people will just want to go and have

Andrew: [00:38:20] a look.

Yep. And you know how inquisitive we are. We'll get too close and

Fred: [00:38:25] that's right. It'll be like the Italian restaurants will do well. I'm not sure. Sure. I perceive the link there, Andrew. I was thinking more edification spaghetti. Okay. There you go. So I'm so slow today. It's been a winner by the week. We're ordinary free.

That's really what it is. I, yeah, I was thinking though, my thoughts went to Hawaii where exactly what you've described happens. People go to look at the lava flows and just get too near and all kinds of horrible things happen to them. Uh, that would be the same with a [00:39:00] black hole, but we'd done it. Yeah.

I'm sure you have melted the issues and things like that. Um, the, um, Italian restaurants need to be well enough away, but isn't it a great, you know, spaghettification restaurant will be a great selling point for the three. I love in the world who, what spaghettification is first, um,

Andrew: [00:39:23] There is, there is a restaurant at the end of the universe.

There is that's right now. Um, moving on from that, uh, the stability of the solar system. Why is it so why isn't stuff crashing into each other? Well, I guess it still is just not as dramatically and as regularly as it used to. At the beginning.

Fred: [00:39:43] That's right, exactly. So, so in, in its early history, 4.5, 7 billion years ago, uh, the stuff was charging around all over the place.

And it was exactly as, uh, as Tim describes, everything was crushing and bumping into each other. [00:40:00] Um, and that's what forms planets, but, um, the planets, uh, as they build, they get more and more massive and that sort of gives them. Um, a bit of a clout in terms of how, you know, the gravitational influence is enough that they can adopt stable orbits.

Um, although it has to be said that we think that in the history of the solar system, Particularly the giant planets, they're all bits of probably migrated in and out of it. And in fact, there's a possibility that at one time, Neptune and Uranus were in a different order, that Uranus was actually the, the, the furthest planet.

Um, but that's a much more, you know, it's a much slower process. We're talking about things over hundreds of millions of years. Uh, and so it's, it's kind of crashing and bumping into each other in slow motion. If I can put it that way, everything settles down, um, the things stabilize. Uh, another example is the Trojan asteroids.

This, these are these two [00:41:00] groups of asteroids and there's 9,000 of them together, uh, which are in Jupiter's orbit, but clustered 60 degrees ahead of Jupiter and 60 degrees behind Jupiter. And what that saying is. Yeah, asteroid you'd think of would normally be in Jupiter's orbit. It would normally be colliding with Jupiter, but Jupiter has got such a huge gravitational influence that it forms these stable positions, the Tulare ground points in front of, and behind it where asteroids cluster.

So it's a kind of gravitational tidying up of the solar system. And, um, that's. Basically what's happened with all the planets resulting in a very stable situation, which is just as well, if you're trying to evolve life on a planet and in particular intelligent life.

Andrew: [00:41:44] Hmm. Uh, yes, I would imagine if things were unstable, we would never have came into

Fred: [00:41:49] being, we wouldn't have made no that's right.

Possibly. No.

Andrew: [00:41:54] All right. Thank you, Tim, for your questions. Very good. Let's move on to our next set of questions. [00:42:00] Uh, from Paul also in Australia, he's a up in sunny Queensland professor Burton,

Fred: [00:42:06] Andrew. This is Paul from Toowoomba in Queensland, Australia. I've got a question about

Andrew: [00:42:10] magnetism and track to beams.

Fred: [00:42:13] Uh, I understand that

Andrew: [00:42:14] some scientists down at the ANU in Canberra have managed to create a tractor beam using a laser, uh, Is this because light is magnetic in nature, as you mentioned back

Fred: [00:42:24] in, I think it was episode two 46, but for us a friend, um, if so cool. But can you explain how it works in terms that, uh,

Andrew: [00:42:33] my year five and year six students at darling

Fred: [00:42:36] hide states cool.

Andrew: [00:42:37] Could understand. That's actually just an excuse. I won't understand anything more advanced than that myself. Anyway. Can't wait

for

Fred: [00:42:44] both of your books to come out. Our, at least one of them is going to be going on the shelf of my mini library at school. And congratulations also on over a

Andrew: [00:42:54] million downloads and more than 250 episodes.

It may

Fred: [00:42:58] have come as a surprise for you, [00:43:00] but it sure as heck wasn't any surprise for us fans long may your work continue. Thank you to you, professor Fred, you Andrew and U2,

Andrew: [00:43:09] Hugh. Amazing work. Can't wait to hear more. Thanks. You Paul. Thank you for the good wishes. Uh, lovely to hear from you. I'm guessing I know which books can end up on the library shelf at the school and sorry about that, Fred, but anyway, yeah.

Okay. Track the boomers and magnetism.

Fred: [00:43:27] Hm. Um, just Paul, thank you very much for that. And just in case you didn't want to put his book on the shelf. I think it looks as though, uh, the new, my new book's going to be called. Um, actually I can't remember what it's going to be called space war, but he's had so many names.

Yeah. Uh, right. Space walk. Yeah. Like it, yeah, I do too. Yeah. It's not, that's actually the name of one of the chapters as well. Uh, great to know that people, um, you know, find our [00:44:00] stuff useful, particularly with the year of five and six students, because they're the people who are the future. They're the ones who are going to put into Stella.

Uh, No, it's a spacecraft in space and things of that sort. So, uh, great to have teachers listening. Um, okay. So how does Paul is right? Uh, there have been tests done. Uh, it's actually not the ANU. It's a company, which is, uh, right next to the Mt. Stromboli observatory. They've got strong links with Mount strong longevity, which is the AMU, uh, but they're kind of spinoff.

They are called electro optical systems or EOS, and their speciality is dealing with I'm trying to the problem or relieve the problem of space junk. There, there is. Um, I think I'm right in saying, cause I was involved with the beginning of this. There is a, uh, what's called a CRC, a co-operative research center, uh, which is called it's the, [00:45:00] um, space.

Something research center. I can't remember what it is, space debris or something like that. Uh, which EOS is part of there you are. There's alpha does an acronyms in there. Uh, so you can see it's a complicated process, but yes, they have indeed, uh, done this business of using lasers to push. Small pieces of debris out of the way in space.

Um, and they've do some very, very clever stuff. But, um, yeah, the basic principle, which is what Paul's asking about is it's not the magnetism so much. Yes, you're right. Excuse me. Light is an electromagnetic wave. It's a vibration of the electrical and magnetic fields in space. Um, so magnetism is involved, but it's, um, in some ways a more, um, excuse me.

Yeah. And magnetic frog in my throat. There it's a more, um, uh, physical process. If I can put than that, all the magnetism is pretty [00:46:00] physical, uh, is to do with the momentum of photons and light particles, which are photons have a momentum, even though they are. They are massless, uh, stationary. We're getting to some intriguing physics here, but, um, if Paul's teaching physics at all, you know, that the momentum of something is the mass times velocity.

Um, and that really relates to the amount of energy that this moving object contains. So I have fairly zero momentum at the moment because I'm sitting still. But if I was running along, my mus and my velocity will be the product. Um, but, uh, lights intriguing. Light particles have momentum, but they don't have any mass because they don't have what's called arrest mass, which is the thing when it's stationary, um, mass changes with velocity because of.

Einstein's special relativity theory. Uh, [00:47:00] and at the speed of light particles effectively do have mass, uh, because they have momentum and it's the momentum that's being transferred from the photons to the particles, um, that allow the beams to be, uh, sorry, the, the, the, the bits of space junk to be moved.

There's another very well known. Um, uh, another well-known, um, example of this Paul, and that is the idea of, uh, light sales in space. And these have now been tested there's at least one experiment been done to show that you can use a light sail, uh, to collect the momentum of the sun's light. And change the orbit of a spacecraft.

It was an experiment that was conducted last year. Uh, so light sales do the same thing. They take photons of light, which are coming from the sun and they're pretty energetic. Uh, and then some of them are mentum is transferred to the solid surface. The LightSail. It gives it an acceleration if you've got enough of them.

And that's the same [00:48:00] principle as actually using a laser to, as a tractor beam, to move things around in orbit. Um, that's a fairly long-winded and complex explanation, but that's kind of what's happening. So, um, it's worth checking up on just, um, check up on the, the, the momentum of light and, and how, how it moves solid objects.

Yeah, I say, yes, you still there.

Andrew: [00:48:29] I was still eating.

Fred: [00:48:30] Um, I lost you for a minute. I thought you'd gone to sleep.

Never do that. Um, I think, I think we've got before connection, as I understand.

Andrew: [00:48:45] I understand the concept of sales, catching a breeze, but is it exactly the same concept in space with light sales, catching light or photons

Fred: [00:48:57] or the momentum? I think it is. [00:49:00] Because it's the, you know, the atoms of, of, uh, air, when you're talking about a light, a sail, uh, catching a breeze, that's the, the atoms of air is transferring them momentum to the sale and giving it a push and acceleration.

So I think it's basically the same principle and I guess the. The the real bottom line in this is, um, as with a sail in a sailing boat, how do you control it? Uh, you need to get all the angles, right. And things of that sort. And that was the neat part about that experiment that was done with the LightSail last year.

I think it was a spacecraft called LightSail two, which was funded by the planetary society. If I remember rightly, uh, and. The, what they showed was that you can, you can actually use your lights out well to give you, um, an idea acceleration that is controllable. In other words, you tilt the LightSail at the right angle, uh, because what they did was they changed the orbit of the spacecraft very, very slightly, but enough to show that it was, it was working

Andrew: [00:49:58] feasible.

Hmm. [00:50:00] That's fascinating. What would light sales need to be made of.

Fred: [00:50:05] They're usually made of Mylar my last sheet. Yeah. Uh, well, my lab is a, it's a thin really thin polymer. Um, uh, it's what you basically, what you use in, um, you know, it's that silver paper that you use in the oven and things like that. It's that kind of thing.

A very thin film. Um, in fact, no, it's not the silver paper, it's the stuff you use to wrap up. Yeah. So, you know, something like glad wrap, which we have here in Australia, which is a food wrapper. I think that's my lab. I think that's a Mylar sheet and you, and what you do is your luminizer. You, you coat it with, uh, with Armenia to make it reflective.

Andrew: [00:50:43] All right. So I could make a light sail in the kitchen, just get some clean film and put a piece of aluminum foil behind it

Fred: [00:50:50] while I've got a LightSail. You have, um, you have a LightSail your problem would be that you'd have to pump all the air out of the kitchen to make it work. That [00:51:00] might not be crazy good.

Yes.

Andrew: [00:51:02] I knew there was going to be a trap. There's always something. Yes. All right, there you go, Paul, hopefully that's answered your questions this week and thank you for sending them into us. And if you would like to send us some questions, you can do that by clicking on the AMA tab on our website. You can send us your message through our email system so you can text it to us or you can record it.

If you've got a, a device with a microphone, we love to hear your voices, but either way we will get them and we will be able to add them to the mix. So thank you again to Tim and Paul. And thank you, Fred. That brings us to the end of yet

Fred: [00:51:42] another episode. It does. Doesn't it amazing how they all happen?

It's a great pleasure, Andrew. Uh, thank you very much for putting up with me too. And, um, I look forward to episode 250, sorry, 260. No, 255. Yes.

[00:52:00] Andrew: [00:52:00] 50 fives next 255

Fred: [00:52:02] 55. Next.

Andrew: [00:52:05] It's all good. It's all good now. And have a nap.

Fred: [00:52:09] Thank you. Fred is

Andrew: [00:52:14] mix a week. Professor Fred Watson, the store number large part of the team here at the space and that's podcast. Download Hugh back in the studio who has now got some heavy editing to do with heavy metal, for sure. And from me, thanks for your company. See you again on the next episode. Bye-bye

at apple podcasts, Google podcasts,

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