Cosmic Q&A: From Redshift to the Moon's Hidden Temperatures

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Andrew Dunkley: Hello again. Thank you for joining us on a Q

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and A edition of Space Nuts. This is where

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the audience asks us questions, we scratch

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our heads and it's all over in about a

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minute. Um, but, uh, if we are

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to answer questions, we may well, um,

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answer, um, the question as to how they're

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going to save the Swiss. Uh, the

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Swift Observatory, which as

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you might recall in a previous episode, was

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under threat of, um, you know, coming back

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into the Earth's atmosphere and being lost

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forever. Well, uh, James, who asked the

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question, is going to be in for a bit of a

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shock on that one. Uh, also a, uh, follow

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up on Redshift. We're going to look at

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temperatures of the moon and a white

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hole, black hole merger. What

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would be the effect? Fred Watson knows, we'll

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ask him on this edition of space

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nuts.

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Generic: 15 seconds. Guidance is internal.

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10, 9. Ignition

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sequence start.

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Professor Fred Watson: Uh, space nuts.

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Generic: 5, 4, 3, 2. 1, 2, 3, 4,

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5, 5, 4, 3, 2, 1.

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Andrew Dunkley: Space nuts.

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Generic: Astronauts report at Beales.

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Andrew Dunkley: And joining us to unrattle all of those

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rattling questions is Professor Fred Watson

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Watson, Astronomer at large. Hello,

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Fred Watson.

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Professor Fred Watson: Hello, Andrew. Fancy seeing you.

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Andrew Dunkley: Long time, long time no see. Yes,

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um, a question without notice.

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Do you always record on the same day and

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time? No, no, we

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don't. No. Uh, it's never that

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easy. That was an easy one to

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answer.

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Professor Fred Watson: Is that from our live, uh, audience?

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Andrew Dunkley: Yes, that's from Moose. G', Day, Moose.

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Yeah, but no, no, we don't. Um,

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it all comes down to who's available

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on whatever given day. And uh,

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today was the day. But, uh, no, it's, it's,

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it sort of jumps around sometimes we have to

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double up. In fact, um, this is the

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first time we've actually recorded together

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for over a month because Fred Watson

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was travelling and we had to double up

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for um, quite a few weeks to get ahead. And

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um, we didn't quite make it, which is why

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Jonty covered things for the last couple of

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weeks. But, uh, we generally try to do

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it in the morning so that we can catch the

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evening viewers in the United States, which

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works, um, out pretty well for most. But then

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most of the people in this part of the world

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are at work.

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Professor Fred Watson: So it's lose, lose.

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Andrew Dunkley: Basically can't cater for the entire world

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at one given moment. But that's, that's,

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that's the way it goes. If we could sort of

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just have one time zone with daylight

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everywhere all the time, it would make it

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easier. But, um, yeah, they're still working

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on that and I'm not joking, they are still

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working on that. They're trying to put up

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these big mirrors and I don't know what else.

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It's weird. Um, do you want to

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tackle some questions, Fred Watson?

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Professor Fred Watson: Yes, please.

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Andrew Dunkley: Thank you.

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Andrew Dunkley: Um, actually, we do have a live question

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straight up, so we'll might jump straight at

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that one.

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What are your thoughts on the red dots as

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seen by the James Webb Telescope?

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Professor Fred Watson: Asks.

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Andrew Dunkley: Good.

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Andrew Dunkley: Interestingly, they're in the news at the

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moment because, uh, there was a storey I only

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read just before we came on live to suggest

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that they think they're about to witness a

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red dot merger.

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Interestingly, yeah.

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Professor Fred Watson: So they're being well studied. Uh, and

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one of them in particular,

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uh, which has a name, I think it's called

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BH1. BH

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is an abbreviation for black hole star number

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one. Uh, and, um,

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this is a little red dot that, unlike many

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of the other ones, is in a

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relatively empty environment. So,

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uh, let's just recap. What are little red

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dots? They're what the penetrating power of

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the James Webb Telescope has revealed for the

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first time, uh, in the early universe, uh, at

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a time when the universe was only, you know,

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a few hundred million years old, we see these

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objects which have now got the name of little

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red dots. Um, they're compact,

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uh, and they are quite

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bright in terms of the amount of energy

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that they, uh, emit. And I think

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BH1, if I remember

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rightly, it's 100 billion times brighter

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than it should be. Whoa. Uh, and.

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But that's leading to

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the suggestion that what we're seeing here

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is a star, which, uh,

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is basically a cloud of gas with

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a supermassive black hole at its centre.

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So if you think about, uh, our knowledge of

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galaxies, most of which seem to have

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supermassive black holes at their centre,

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they're made of stars. Uh, that star

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formation process takes place over billions

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of years. Um, and we used to think that

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it took a long time for these black holes to

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become supermassive by, you know, them

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being basically, uh, gobbling up each other,

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uh, gobbling up material so that they became

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supermassive. But we see supermassive black

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holes now so early in the universe. And it

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looks as though BH

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got one at its centre. I think it's 50,000 or

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thereabouts times the mass of the sun. Can't

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remember the details. Um, I've had an

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operation since I read all that. Uh,

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so, um, um, the evidence seems

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to be that we are seeing a new class of

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object, uh, essentially a galaxy.

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Something not the size of a galaxy because

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Their dimensions are kind of solar system

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size. They're much bigger than the solar

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system, but they're clouds of gas.

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And we think that they are energised

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by the accretion disc. The way material is

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swirling around the black hole at their

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centre and that's raising temperatures in the

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middle to very high degrees until you get

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very high levels of energy emission, which is

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why they're said to be 100 billion times

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brighter than they should be. So it looks as

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though we're on the track of identifying

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these little red dots as something quite new

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and kind of unexpected. I'm sure they were

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predicted that we'd find, uh, stars

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made basically of nothing but gas in a black

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hole, uh, rather than, you know, other

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stars. Uh, and um, that

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seems to be what they are. So. Yeah, watch

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this. Space though. Um, you know.

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Yes, Moose, thanks.

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Andrew Dunkley: No, it wasn't Moose. It was good. Sorry, but

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thanks for the question.

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Uh, we've got an audio question now. This is

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from James.

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Andrew Dunkley: Hi, this is James in high western England.

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So as of 6 July, there's a

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spacecraft called Link which will boost the

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decaying orbit of the Swift satellite.

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What will it do to boost the orbit and what

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even does that mean, to boost an

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orbit? Um, I m. Guess I assume

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that pushing it from underneath might not

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be the answer. So look forward to

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hearing how it might actually do that.

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Thanks, James.

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Andrew Dunkley: Thank you, James. Hope all is well in, I

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think you said, Howick in the uk.

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Professor Fred Watson: High Wycombe.

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Andrew Dunkley: High Wycombe.

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Andrew Dunkley: All right.

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Andrew Dunkley: Okay. Could have been either.

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Um, We've got some bad news for you, James,

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I'm afraid, haven't we, Fred Watson?

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Professor Fred Watson: Yeah. So, uh,

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it's really sad because, um, this

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project has been a bit of a poster child

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for NASA because normally their projects take

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decades to come into fruition. But

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they tasked company, uh,

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something like a. With a year's notice or

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something, uh, to develop

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a spacecraft, uh, and actually

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um, basically work out how you could rescue

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the Swift spacecraft. So the storey is Swift

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is uh, an elderly SpaceCraft

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launched in 2004 to study gamma ray

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bursts. But it's been so successful,

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uh, that there was a uh, real

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uh, I guess desire to uh, to save

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it because its orbit is decaying.

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And as of later this year we expect

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it, Its orbit will actually get

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so much atmospheric drag that it will decay

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very quickly and the spacecraft, the Swift

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spacecraft will burn up in the atmosphere.

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So, um, the Link mission, uh,

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was a joint, um, project

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between NASA and a company called

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Catalyst, Catalyst Space. Uh,

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and indeed the Link spacecraft was launched

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on July 3

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with every intention of rendezvousing with

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the Swift spacecraft and lifting its orbit.

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And I'll get onto that in a minute because

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that's basically James's question.

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But what happened was um, they had an

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attitude control issue. Uh,

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and so very quickly the,

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and probably within weeks link, uh,

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the spacecraft that was going to save Swift

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just started tumbling out of control.

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Um, and we got an announcement uh,

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very soon after that that the spacecraft

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would not capture or boost the Swift

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satellite's altitude as planned.

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Um, I think

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they're still attempting

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to rendezvous with Swift. In other

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words to bring the Link spacecraft close to

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Swift just to cheque that

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all their capabilities in terms of

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rendezvous uh, are working. But

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because of this out of control tumbling,

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um, they're not going to be able to do

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anything on that. Um,

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so um, it's turning into a

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mission that is a face saving mission in a

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way. Uh, there is a nice piece on

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our own friend Universe today. Uh, they've

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got a nice piece on it called NASA Announces

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Next Steps for Swift Rescue Mission. And it

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has a lot of quotes from uh, people like

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uh, the NASA administrator Jared Isaacman,

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uh, and, and other people involved, uh,

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Catalyst Space have released a statement,

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um, all of which is you know, basically

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saying that they, they'd hope for more

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science from Swift. Um, I think

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this is a comment from Sean

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Domagal Goldman who's Director of

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Astrophysics at NASA, uh, who says we were

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all hoping for more science from Swift, but

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we knew the takeaways from this mission would

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be worthwhile either way. We've gained so

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much through the series of accomplishments up

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to this point. Building, testing and

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operating. This mission has already

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strengthened America's space industry

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pipeline, advancing in space

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servicing capabilities in completely new

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ways. And I think that's a reflection of the

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fact that this was all done in double quick

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time. Uh, even though it's in the end not

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succeeded, um, it has been um, a

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mission from which people have learned a lot.

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So just going back to James's question, how

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do you boost uh, the

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00:11:14.270 --> 00:11:16.950
orbit or increase the orbit of a spacecraft?

266
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Uh, what you have to do is you have to

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increase its velocity. And so

268
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um, what I think the Link

269
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spacecraft would have done would have been

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and I think it had three arms that could

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grapple onto Swift ont

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hard points on Swift's sort of

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fuselage, what they call the bus, the main

274
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part of the satellite. So I think it was

275
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three that it will grab hold of and then you

276
00:11:41.730 --> 00:11:43.890
use the link, uh thrusters

277
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to apply a velocity or

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an acceleration uh, essentially in the

279
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direction of travel. Uh, because remember,

280
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all satellites are essentially travelling

281
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horizontally. They're all moving in

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orbits that are parallel to the Earth. Of

283
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course, it's the fact that there's a sphere

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that means the orbit is a circ. Um, so what

285
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you do is you boost its

286
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velocity. And what that does is

287
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it raises what we call the apogee.

288
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So it elongates the ellipse

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that the spacecraft

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orbit is in. Um, so

291
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you boost its velocity and

292
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you get an extended ellipse. And the near

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part of the ellipse, what we call perigee,

294
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the part closest to the earth, sort of where

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you started from, that's still at the same

296
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height, but you've given the far part,

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um, the apogee a much higher

298
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radius. And then what you do is,

299
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uh, at the apogee, you

300
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boost it again, you boost the velocity again.

301
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And that lifts the perigee, that actually

302
00:12:49.290 --> 00:12:51.450
lifts the near point. So it's a two step

303
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process. Uh, but it's all about just

304
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increasing the velocity of the spacecraft.

305
00:12:55.610 --> 00:12:58.490
And that automatically lifts the orbit,

306
00:12:58.580 --> 00:13:00.250
uh, in a way that I've described.

307
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Andrew Dunkley: That's how it works in theory, James. It

308
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unfortunately didn't happen. The rescue

309
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missions failed. But uh, the good news news

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is Swift will continue to operate. Uh,

311
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they've restarted um, its observations,

312
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uh, but it is in a very rapid

313
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decaying orbit. And they expect re

314
00:13:20.110 --> 00:13:23.030
entry late, uh, well, not so long

315
00:13:23.990 --> 00:13:25.190
now. Late this year.

316
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Andrew Dunkley: Late.

317
00:13:26.310 --> 00:13:29.030
Andrew Dunkley: We're entering late this year already. So we

318
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are.

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Professor Fred Watson: That's right. Yeah. I don't think it's much

320
00:13:31.070 --> 00:13:31.430
longer.

321
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Andrew Dunkley: I only got a couple of months to live.

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Unfortunately they couldn't save it. But um,

323
00:13:35.910 --> 00:13:38.750
yeah, I

324
00:13:38.750 --> 00:13:41.620
guess they were very hopeful. But um,

325
00:13:41.890 --> 00:13:44.370
it was a pretty last minute thing to try and

326
00:13:44.370 --> 00:13:46.850
do and um, it just didn't work out,

327
00:13:47.410 --> 00:13:50.290
unfortunately. Got um, a

328
00:13:50.290 --> 00:13:52.650
message from Europe as well. Someone's up at

329
00:13:52.650 --> 00:13:54.850
4am and I asked why and he said my little

330
00:13:54.850 --> 00:13:56.850
toddler woke me up. They do that.

331
00:13:57.730 --> 00:14:00.650
They do that. But um, anyway, glad you found

332
00:14:00.650 --> 00:14:03.650
us. Uh, thank you James for the question.

333
00:14:03.780 --> 00:14:05.330
Uh, we'll move straight onto our next

334
00:14:05.330 --> 00:14:08.160
question from Dale, who's in New Zealand.

335
00:14:08.200 --> 00:14:10.320
Uh, he's referring to a question that came

336
00:14:10.320 --> 00:14:12.920
from Roger the trucker, which uh, I think we

337
00:14:12.920 --> 00:14:15.880
covered a few weeks ago. Um, who asked?

338
00:14:15.880 --> 00:14:18.760
Is distant light redshifted? What happens

339
00:14:18.760 --> 00:14:21.760
to the lost energy? And Dale says

340
00:14:21.760 --> 00:14:24.400
surely no energy is lost. Isn't it just

341
00:14:24.480 --> 00:14:25.280
stretched?

342
00:14:27.280 --> 00:14:30.160
Professor Fred Watson: Yes, that's right. So, excuse me, but

343
00:14:30.400 --> 00:14:32.960
longer wavelength, which is what you stretch

344
00:14:32.960 --> 00:14:35.200
it into, um, means,

345
00:14:36.360 --> 00:14:39.210
um, means that the energy that's

346
00:14:39.210 --> 00:14:42.210
carried is less. Uh, and

347
00:14:42.610 --> 00:14:45.250
I guess it's like, you know,

348
00:14:45.890 --> 00:14:48.730
the particle wave duality. The

349
00:14:48.730 --> 00:14:50.850
fact that we can think of light as both a

350
00:14:50.850 --> 00:14:53.170
particle and as a wave. You can think of it

351
00:14:53.250 --> 00:14:55.490
as a particle with certain energy, a photon,

352
00:14:55.980 --> 00:14:57.890
uh, or you can think of it as a wave with a

353
00:14:57.890 --> 00:14:59.370
certain wavelength. And the longer the

354
00:14:59.370 --> 00:15:01.930
wavelength, the lower the energy. So we talk

355
00:15:01.930 --> 00:15:04.130
about high energy astrophysics as being

356
00:15:04.130 --> 00:15:06.610
things that. Where we use gamma rays and X

357
00:15:06.610 --> 00:15:08.510
rays to. To probe space.

358
00:15:09.550 --> 00:15:12.470
So, um, I do remember we

359
00:15:12.470 --> 00:15:15.390
looked at this question and got a number of

360
00:15:15.390 --> 00:15:18.230
different answers. Um, most of

361
00:15:18.230 --> 00:15:20.510
which were don't worry about it.

362
00:15:22.670 --> 00:15:25.670
Which is kind of, uh, what our listener

363
00:15:25.670 --> 00:15:28.630
is, uh, saying, don't worry about it.

364
00:15:28.630 --> 00:15:29.550
It'll be all right. Um,

365
00:15:32.350 --> 00:15:34.190
there is a suggestion that some of that

366
00:15:34.190 --> 00:15:37.060
energy, uh, effectively goes

367
00:15:37.060 --> 00:15:38.860
into raising the background temperature of

368
00:15:38.860 --> 00:15:41.860
the universe. By a tiny gazillionth of

369
00:15:41.860 --> 00:15:44.860
a degree. Uh, but there's another point of

370
00:15:44.860 --> 00:15:46.740
view. It's interesting. It's worth, um, you

371
00:15:46.740 --> 00:15:48.940
know, having a look and, uh. Going down the

372
00:15:48.940 --> 00:15:50.900
rabbit hole. I, uh, haven't had time to do

373
00:15:50.900 --> 00:15:53.050
that again. Um, but, um.

374
00:15:53.810 --> 00:15:55.740
Uh, yeah, go down the rabbit hole and have a

375
00:15:55.740 --> 00:15:57.300
look at what people think about the energy

376
00:15:57.300 --> 00:16:00.220
loss, uh, from, um. The redshift

377
00:16:00.460 --> 00:16:02.560
energy is lost. It goes somewhere, uh,

378
00:16:02.620 --> 00:16:05.140
because the universe is a closed system. Uh,

379
00:16:05.330 --> 00:16:08.120
um. My understanding, as it was always. That

380
00:16:08.120 --> 00:16:09.960
it basically heats the cosmic microwave

381
00:16:09.960 --> 00:16:11.520
background very, very slightly.

382
00:16:12.080 --> 00:16:14.520
Andrew Dunkley: That makes sense, yes. Hope that answers your

383
00:16:14.520 --> 00:16:16.400
question, Dale. Thanks for sending it in and

384
00:16:16.400 --> 00:16:17.920
hope all is well in New Zealand.

385
00:16:18.560 --> 00:16:21.200
This is space nuts. Andrew Dunkley here on a

386
00:16:21.200 --> 00:16:23.040
Q and A edition with Professor Fred Watson

387
00:16:23.040 --> 00:16:23.680
Watson.

388
00:16:26.160 --> 00:16:28.000
Okay, Houston, we've had a problem here.

389
00:16:28.000 --> 00:16:28.640
Generic: This is Houston.

390
00:16:28.640 --> 00:16:30.920
Andrew Dunkley: Say again, please. Houston, we've had about.

391
00:16:30.920 --> 00:16:32.920
We've had a main B plus undervolt. Roger,

392
00:16:32.920 --> 00:16:35.280
main B undervolt. Okay, standby 13. We're

393
00:16:35.280 --> 00:16:37.940
looking at it, Stacey, but I'm going to let a

394
00:16:37.940 --> 00:16:39.700
cat out of a bag here, Fred Watson. In my,

395
00:16:39.830 --> 00:16:42.780
um, new trilogy that. It's just

396
00:16:42.780 --> 00:16:44.980
been released and I think I've sold one copy.

397
00:16:45.370 --> 00:16:48.220
Um, the main B bus

398
00:16:48.220 --> 00:16:50.020
undervolt problem on Apollo 13.

399
00:16:50.660 --> 00:16:51.220
Professor Fred Watson: All right.

400
00:16:51.620 --> 00:16:53.940
Andrew Dunkley: I used that in. I used that in one of the

401
00:16:53.940 --> 00:16:55.540
books just for fun.

402
00:16:56.420 --> 00:16:56.980
Professor Fred Watson: Love it.

403
00:16:57.700 --> 00:16:58.180
Andrew Dunkley: Yeah.

404
00:16:58.260 --> 00:17:00.980
Professor Fred Watson: Anyway, it's nice to put these little, little

405
00:17:00.980 --> 00:17:02.820
snippets in. I've done that in a few of my

406
00:17:02.820 --> 00:17:05.500
books that put things in it that probably I'm

407
00:17:05.500 --> 00:17:07.340
the only person would know that I was

408
00:17:07.340 --> 00:17:08.800
alluding something else.

409
00:17:08.960 --> 00:17:11.120
Andrew Dunkley: I do it a lot. I think I've done it a few

410
00:17:11.120 --> 00:17:13.520
times in this series. Just for fun. And the

411
00:17:13.520 --> 00:17:15.240
people who know will know. The people who

412
00:17:15.240 --> 00:17:17.320
don't will just keep reading and it'll just

413
00:17:17.320 --> 00:17:18.880
be part of the storey, so. That's right,

414
00:17:19.360 --> 00:17:19.840
yeah.

415
00:17:19.990 --> 00:17:22.280
Um, let's go to our next question from one of

416
00:17:22.280 --> 00:17:24.720
our regular, uh, contributors. Here is Fred.

417
00:17:25.360 --> 00:17:28.000
Andrew Dunkley: Hello, friend. And Andrew. This is

418
00:17:28.000 --> 00:17:30.240
Fred calling you from

419
00:17:30.240 --> 00:17:32.960
Minnesota. Thank you for your podcast.

420
00:17:33.200 --> 00:17:36.200
I never miss an episode for it. I have

421
00:17:36.200 --> 00:17:39.200
a question for you about the temperature

422
00:17:39.280 --> 00:17:42.200
on the moon. Now, it's well

423
00:17:42.200 --> 00:17:45.120
known that the temperature on the surface

424
00:17:45.600 --> 00:17:48.480
swings greatly with the orbit of the

425
00:17:48.480 --> 00:17:51.120
moon. But what about underneath

426
00:17:51.280 --> 00:17:53.360
the moon as below its surface?

427
00:17:54.160 --> 00:17:57.000
How constant is it? Does it also

428
00:17:57.000 --> 00:17:59.960
swing around? Does it matter how deep

429
00:17:59.960 --> 00:18:02.040
you go underneath the moon?

430
00:18:03.000 --> 00:18:05.880
This has, of course, relevance

431
00:18:06.040 --> 00:18:08.600
to putting people on the moon and living

432
00:18:09.080 --> 00:18:11.480
on them. Thank you very much

433
00:18:12.120 --> 00:18:13.960
for the question. Bye now.

434
00:18:14.680 --> 00:18:16.840
Andrew Dunkley: Thank you, Fred. He brings up a really good

435
00:18:16.840 --> 00:18:19.600
point. We are going to have people spending

436
00:18:19.600 --> 00:18:21.480
time on the moon in the not too distant

437
00:18:21.480 --> 00:18:23.480
future and some of them will, you know,

438
00:18:23.480 --> 00:18:26.000
they're not just going to go up and kick the

439
00:18:26.000 --> 00:18:27.720
sand and then come home again like you do

440
00:18:27.720 --> 00:18:29.560
when you go to the beach. They'll be up there

441
00:18:29.560 --> 00:18:32.380
for a decent period of time. Um,

442
00:18:32.480 --> 00:18:35.080
I'd say rotating rosters of weeks or

443
00:18:35.080 --> 00:18:37.480
whatever. Uh, how are they going to deal with

444
00:18:37.480 --> 00:18:39.960
these temperatures? Because, uh, as far as I

445
00:18:39.960 --> 00:18:42.960
recall, the moon is one of

446
00:18:42.960 --> 00:18:45.960
the coldest places in the solar system, is it

447
00:18:45.960 --> 00:18:46.240
not?

448
00:18:47.120 --> 00:18:49.760
Professor Fred Watson: And the warmest as well. Um, it's

449
00:18:49.760 --> 00:18:51.240
temperature variation. I always get these

450
00:18:51.240 --> 00:18:54.000
figures wrong, but it's almost a 300 degree

451
00:18:54.000 --> 00:18:56.920
Celsius variation from minus

452
00:18:56.920 --> 00:18:59.360
150 to plus 150. They're slightly different.

453
00:18:59.900 --> 00:19:00.700
Andrew Dunkley: Just like Dubbo.

454
00:19:03.900 --> 00:19:05.420
Professor Fred Watson: Yes, it's a lot like Dubbo.

455
00:19:06.700 --> 00:19:09.220
Andrew Dunkley: No, I think our temperature variations are

456
00:19:09.220 --> 00:19:12.180
somewhere around 50 degrees, but it's still.

457
00:19:12.180 --> 00:19:14.420
Professor Fred Watson: Yeah, that's right. That's remarkable.

458
00:19:14.420 --> 00:19:14.870
Andrew Dunkley: Celsius.

459
00:19:14.870 --> 00:19:17.580
Professor Fred Watson: Um, 50. Celsius. Yes.

460
00:19:17.900 --> 00:19:19.580
What's your lowest that you've ever had?

461
00:19:20.060 --> 00:19:22.940
Andrew Dunkley: Minus 7.4, I think.

462
00:19:23.500 --> 00:19:25.810
Which was only a couple of years ago. Yeah,

463
00:19:25.810 --> 00:19:28.210
yep, something like that.

464
00:19:29.010 --> 00:19:31.970
Quite. Our warmest is 40.

465
00:19:32.930 --> 00:19:35.490
No, we got to 50 the year before last.

466
00:19:36.130 --> 00:19:38.770
So, uh, there you go, it's 50. 50. Nearly 58

467
00:19:38.770 --> 00:19:40.050
degrees variation.

468
00:19:41.490 --> 00:19:43.970
Professor Fred Watson: Yeah, yeah. Eat your heart out, Moon.

469
00:19:44.930 --> 00:19:47.810
Because the moon's much higher. And

470
00:19:47.810 --> 00:19:49.930
of course the reason for that is that there's

471
00:19:49.930 --> 00:19:52.650
no atmosphere. So during the day you've got

472
00:19:52.650 --> 00:19:55.050
the sun's radiation beaming down, heating the

473
00:19:55.050 --> 00:19:57.510
surface. And, uh, it's the surf temperature

474
00:19:57.510 --> 00:19:59.310
that we talk about when we mean these things.

475
00:19:59.390 --> 00:20:02.230
Well over 100 degrees and at night that just

476
00:20:02.230 --> 00:20:04.830
all radiates into space, um, and

477
00:20:05.230 --> 00:20:07.950
the surface cools to minus 100

478
00:20:08.030 --> 00:20:10.030
and something degrees as well. I can't

479
00:20:10.030 --> 00:20:11.390
remember that. I can never remember the exact

480
00:20:11.390 --> 00:20:13.790
figures. I should have them in my head. But

481
00:20:14.350 --> 00:20:16.710
the good news is, and I think, you know, this

482
00:20:16.710 --> 00:20:19.230
is what Fred's alluding to is that

483
00:20:20.030 --> 00:20:22.670
the, the lunar soil

484
00:20:23.650 --> 00:20:26.580
um, is very poor. It's a very poor

485
00:20:26.580 --> 00:20:29.380
conductor of heat. Ah, and

486
00:20:29.620 --> 00:20:32.620
so that means that, you know, you don't have

487
00:20:32.620 --> 00:20:34.900
to go down

488
00:20:35.460 --> 00:20:38.260
too far to find that those temperatures

489
00:20:38.420 --> 00:20:41.140
even out quite a bit. I'm reading

490
00:20:41.140 --> 00:20:44.020
from um, from a, um, an article

491
00:20:44.020 --> 00:20:46.650
actually on lunar surface temperature. Uh,

492
00:20:46.900 --> 00:20:49.140
I'm going to quote from it. Measurements from

493
00:20:50.230 --> 00:20:52.550
the Apollo 15 and 17

494
00:20:52.630 --> 00:20:55.230
missions show that temperatures

495
00:20:55.230 --> 00:20:58.120
35 centimetres below the surface, that's ah,

496
00:20:58.230 --> 00:21:01.190
not much more than a foot, are ah, 40 to

497
00:21:01.190 --> 00:21:03.270
45 degrees Kelvin,

498
00:21:03.830 --> 00:21:06.350
warmer than the minimum

499
00:21:06.350 --> 00:21:09.030
surface nighttime temperature, avoiding the

500
00:21:09.030 --> 00:21:11.710
harshest cold. So it brings the

501
00:21:11.710 --> 00:21:14.270
temperature up and that's only a foot or so

502
00:21:14.270 --> 00:21:17.030
below the surface. And then continuing the

503
00:21:17.030 --> 00:21:19.940
same article, um, by the time you

504
00:21:19.940 --> 00:21:22.460
get to getting on for a metre, 80

505
00:21:22.700 --> 00:21:25.540
centimetres, 30 inches if you prefer

506
00:21:25.540 --> 00:21:28.540
that below the surface the

507
00:21:29.180 --> 00:21:32.180
day and night variations are

508
00:21:32.180 --> 00:21:35.020
uh, imperceptible. So that

509
00:21:35.020 --> 00:21:37.820
is incredible really that you've only

510
00:21:37.820 --> 00:21:40.220
got to go um, you know,

511
00:21:40.940 --> 00:21:43.180
80 centimetres less than a metre below the

512
00:21:43.180 --> 00:21:46.170
surface and the material there

513
00:21:46.170 --> 00:21:48.210
does not see these enormous

514
00:21:48.770 --> 00:21:51.730
swings in temperature. Uh, it's become

515
00:21:51.810 --> 00:21:54.650
imperceptible. Um, and then

516
00:21:54.650 --> 00:21:57.410
when you get to below a metre, um,

517
00:21:58.290 --> 00:22:01.210
then you get an average temperature which is

518
00:22:01.210 --> 00:22:02.850
kind of the average of the hottest and the

519
00:22:02.850 --> 00:22:05.010
coldest. And that is very nice because it

520
00:22:05.010 --> 00:22:07.410
makes it about 20 degrees Celsius

521
00:22:07.970 --> 00:22:09.650
or um, you know,

522
00:22:10.940 --> 00:22:13.240
that sort of basically that uh,

523
00:22:14.060 --> 00:22:16.700
20 degrees Celsius is.

524
00:22:17.420 --> 00:22:19.820
I beg your pardon, it's minus 20 degrees

525
00:22:19.820 --> 00:22:22.300
Celsius, not 20 degrees but still

526
00:22:22.780 --> 00:22:25.500
within reason. Um, and so

527
00:22:26.780 --> 00:22:29.420
it means that if you can look for caves

528
00:22:29.900 --> 00:22:32.620
and pits in the lunar, uh,

529
00:22:32.620 --> 00:22:35.460
regolith in the lunar soil then

530
00:22:35.460 --> 00:22:38.200
you've got a really good chance of having a

531
00:22:38.200 --> 00:22:41.160
place where you've got, without any air

532
00:22:41.160 --> 00:22:43.840
conditioning or anything. You've got a

533
00:22:43.840 --> 00:22:46.480
ready temperature round about 17

534
00:22:46.560 --> 00:22:48.960
degrees Celsius, uh, day and night

535
00:22:49.600 --> 00:22:52.600
without these extremes. So um, that's

536
00:22:52.600 --> 00:22:55.160
really good news. I think from the

537
00:22:55.160 --> 00:22:57.880
perspective of our future exploration of the

538
00:22:57.880 --> 00:23:00.880
moon, uh, that this variation uh,

539
00:23:01.200 --> 00:23:03.440
is only on the surface. The extreme

540
00:23:04.000 --> 00:23:05.830
variation is only on the surface itself.

541
00:23:06.890 --> 00:23:09.460
Andrew Dunkley: M There you go Fred. So good question, thanks

542
00:23:09.460 --> 00:23:12.100
for asking it. Uh, and uh, great to hear from

543
00:23:12.100 --> 00:23:12.540
you again.

544
00:23:13.230 --> 00:23:15.940
Uh, our European listener whose

545
00:23:15.940 --> 00:23:18.740
toddler woke them up at 4am has sent us a

546
00:23:18.740 --> 00:23:21.220
note Saying he's an astrobiologist working in

547
00:23:21.220 --> 00:23:24.130
the ExoMars science team. Uh,

548
00:23:24.130 --> 00:23:26.940
he's a big fan of the show and I thought,

549
00:23:26.940 --> 00:23:28.590
oh, I'm going to look this up. ExoMars, uh,

550
00:23:29.300 --> 00:23:32.220
science team, uh, is um,

551
00:23:32.300 --> 00:23:35.100
looking into ExoMars, uh, missions,

552
00:23:38.210 --> 00:23:40.170
uh, particularly in um,

553
00:23:41.800 --> 00:23:44.680
part, uh, working on the uh, Roslyn Franklin

554
00:23:44.760 --> 00:23:47.400
rover. And they're trying to find out

555
00:23:47.480 --> 00:23:49.680
did Mars ever have life and could traces of

556
00:23:49.680 --> 00:23:52.400
it still be preserved underground. So um, I

557
00:23:52.400 --> 00:23:55.280
looked that up and since then another note's

558
00:23:55.280 --> 00:23:58.120
come through. Our Rover has a 2 metre drill

559
00:23:58.120 --> 00:24:00.600
to get samples from Mars. Uh, subsurface

560
00:24:00.600 --> 00:24:03.070
organics will be preserved. Um,

561
00:24:03.880 --> 00:24:05.760
what do you think will we find? And

562
00:24:05.760 --> 00:24:08.400
biosignatures, always throwing you a

563
00:24:08.400 --> 00:24:09.120
curvy there.

564
00:24:10.800 --> 00:24:12.640
Professor Fred Watson: The trouble is it's knowing that they are

565
00:24:12.800 --> 00:24:15.540
biosignatures. Yes, he or she, uh.

566
00:24:15.540 --> 00:24:18.300
Well, look, an honour to have somebody uh,

567
00:24:18.720 --> 00:24:20.720
working right in the front line of this

568
00:24:20.720 --> 00:24:23.160
stuff, particularly in Europe, very close to

569
00:24:23.160 --> 00:24:25.600
my heart. Uh, it's an honour to have you

570
00:24:25.680 --> 00:24:28.160
listening and um, participating in the show.

571
00:24:28.160 --> 00:24:29.810
Thank you very much. Um,

572
00:24:31.040 --> 00:24:33.890
the issue with biosignatures is are

573
00:24:33.890 --> 00:24:36.810
they biosignatures or are there false alarms?

574
00:24:36.810 --> 00:24:38.970
And it is so difficult

575
00:24:39.610 --> 00:24:42.330
to essentially eliminate everything

576
00:24:42.410 --> 00:24:45.010
else that could be causing whatever that

577
00:24:45.010 --> 00:24:46.870
biosignature is, whether it's uh,

578
00:24:47.610 --> 00:24:50.400
microbial structure or uh,

579
00:24:50.650 --> 00:24:53.650
metabolic activity or whatever it is. It's

580
00:24:53.650 --> 00:24:56.490
very hard to eliminate what you might call

581
00:24:56.730 --> 00:24:59.530
natural, non biological, uh, origins.

582
00:24:59.850 --> 00:25:02.720
But digging deep is the way to go. Uh,

583
00:25:02.720 --> 00:25:05.590
I think the ExoMars project has

584
00:25:05.670 --> 00:25:08.390
had mixed fortunes because it was originally

585
00:25:09.100 --> 00:25:11.510
uh, going to be uh, a joint

586
00:25:11.590 --> 00:25:14.440
European Russian project, um,

587
00:25:14.550 --> 00:25:16.990
which I think was shelved probably at the

588
00:25:16.990 --> 00:25:19.590
time of the invasion of Crimea in

589
00:25:19.590 --> 00:25:22.260
2014. I think that's what happened. Um,

590
00:25:22.790 --> 00:25:25.430
and so, um, But I think Europe

591
00:25:25.430 --> 00:25:27.910
is carrying on its own,

592
00:25:28.330 --> 00:25:31.190
uh, I wish, uh, uh, our listeners and

593
00:25:31.190 --> 00:25:33.110
everybody working with them every success,

594
00:25:33.810 --> 00:25:35.670
uh, because these are things we want to know.

595
00:25:35.990 --> 00:25:38.630
Andrew Dunkley: Yeah, absolutely. Uh, Issa says the rover

596
00:25:38.630 --> 00:25:41.230
will target an ancient clay rich region where

597
00:25:41.230 --> 00:25:43.710
minerals formed in the presence of abundant

598
00:25:43.710 --> 00:25:46.069
liquid water and could have preserved

599
00:25:46.069 --> 00:25:47.830
evidence of ancient life. And their launch

600
00:25:48.550 --> 00:25:51.110
window is set for late

601
00:25:51.110 --> 00:25:53.990
2028 at this stage. So. Yes,

602
00:25:54.070 --> 00:25:55.870
fingers crossed. That'll be exciting. Looking

603
00:25:55.870 --> 00:25:57.430
forward to that. Thanks for letting us know.

604
00:26:00.090 --> 00:26:01.370
Generic: Roger, in your labs right here.

605
00:26:01.370 --> 00:26:02.890
Andrew Dunkley: Also space nuts.

606
00:26:03.130 --> 00:26:05.770
Final question, Fred Watson. This comes from

607
00:26:05.770 --> 00:26:08.530
Kevin. So, uh, this is uh, going to be more

608
00:26:08.530 --> 00:26:11.290
of a hypothetical. I understand we have no

609
00:26:11.290 --> 00:26:13.930
observational evidence of white holes, but we

610
00:26:13.930 --> 00:26:16.290
do have a fair mathematical understanding of

611
00:26:16.290 --> 00:26:19.170
them. So my question is if a white hole

612
00:26:19.170 --> 00:26:21.690
actually existed, what would happen

613
00:26:22.010 --> 00:26:24.690
if it Merged with a black hole. Would they

614
00:26:24.690 --> 00:26:26.490
essentially cancel each other out? What

615
00:26:26.490 --> 00:26:29.270
would, would be left afterwards? Just, uh,

616
00:26:29.480 --> 00:26:31.760
some random thoughts. I was thinking, uh, and

617
00:26:31.760 --> 00:26:34.120
would love some insight on what you guys

618
00:26:34.120 --> 00:26:36.040
think. Amazing show. Keep up the great work,

619
00:26:36.040 --> 00:26:38.080
Kevin. I know the answer to this one,

620
00:26:38.080 --> 00:26:38.520
Fred Watson.

621
00:26:39.000 --> 00:26:41.760
Professor Fred Watson: Good, good. It would

622
00:26:41.760 --> 00:26:44.760
be a grey hole. Uh, well,

623
00:26:44.760 --> 00:26:47.760
that's. Could be right. My mind

624
00:26:47.760 --> 00:26:50.640
went straight to when a black hole and a

625
00:26:50.640 --> 00:26:52.600
Whitehall love each other very much.

626
00:26:52.760 --> 00:26:53.400
Andrew Dunkley: Oh, boy.

627
00:26:53.400 --> 00:26:53.880
Professor Fred Watson: Then they

628
00:26:56.610 --> 00:26:58.530
come together and make a grey hole. How's

629
00:26:58.530 --> 00:27:01.410
that? Ah, yeah, um, that's a

630
00:27:01.410 --> 00:27:03.970
good question. And I, Sorry, I'm,

631
00:27:04.290 --> 00:27:06.710
I'm still a little bit, um,

632
00:27:06.850 --> 00:27:08.860
unprepared for these, um,

633
00:27:09.570 --> 00:27:11.890
because my focus is on making my knee better.

634
00:27:12.370 --> 00:27:15.290
But, uh, I would like to cheque that out and

635
00:27:15.290 --> 00:27:17.090
see what the pundits think. In the world of

636
00:27:17.090 --> 00:27:19.410
black holes and white holes, we've never seen

637
00:27:19.890 --> 00:27:22.890
any evidence for a white hole. Um, you

638
00:27:22.890 --> 00:27:25.240
can create a white hole

639
00:27:25.240 --> 00:27:28.120
mathematically, uh, by reversing the

640
00:27:28.120 --> 00:27:31.040
time, uh, factor in the equations of

641
00:27:31.040 --> 00:27:33.200
relativity, and then you get a white hole

642
00:27:33.200 --> 00:27:35.240
rather than a black hole. But that does not

643
00:27:35.240 --> 00:27:37.840
mean that they exist. We do know that black

644
00:27:37.840 --> 00:27:40.640
holes exist. The evidence for their existence

645
00:27:40.640 --> 00:27:43.130
is absolutely compelling. Um,

646
00:27:43.560 --> 00:27:46.440
I, you know, the idea of them cancelling out

647
00:27:46.440 --> 00:27:49.240
is the one that has the most appeal, because

648
00:27:49.320 --> 00:27:51.600
that sounds feasible. Gravitational wells.

649
00:27:51.600 --> 00:27:53.210
Yeah. Of different kinds of,

650
00:27:54.570 --> 00:27:57.240
uh. But I, I, That's a flippant comment. I'll

651
00:27:57.240 --> 00:27:59.080
need to look at this again. Perhaps you can

652
00:27:59.080 --> 00:28:01.910
remind me until we can get back to Kevin, uh,

653
00:28:01.910 --> 00:28:04.000
and talk about what happens when you get a

654
00:28:04.000 --> 00:28:04.720
grey hole.

655
00:28:05.280 --> 00:28:08.200
Andrew Dunkley: Yeah. Um, I think you end up

656
00:28:08.200 --> 00:28:09.840
in a, uh, retirement village.

657
00:28:09.840 --> 00:28:10.160
Professor Fred Watson: Sure.

658
00:28:14.160 --> 00:28:16.480
Andrew Dunkley: And Moose says, aren't white holes still

659
00:28:16.480 --> 00:28:18.720
theory only? Yes, absolutely.

660
00:28:18.800 --> 00:28:19.940
Professor Fred Watson: That's right. Absolutely right.

661
00:28:21.210 --> 00:28:22.850
Andrew Dunkley: It's like many things in the universe, the

662
00:28:22.850 --> 00:28:25.050
mathematics says, yes, they could exist,

663
00:28:26.100 --> 00:28:28.890
um, but we've never seen them and

664
00:28:29.130 --> 00:28:31.130
we don't have any other proof, so.

665
00:28:31.930 --> 00:28:32.570
Professor Fred Watson: Quite fun.

666
00:28:32.970 --> 00:28:35.130
Andrew Dunkley: Yes, indeed. Uh, thanks for the question,

667
00:28:35.130 --> 00:28:37.210
Kevin. Thanks to everybody who contributed.

668
00:28:37.210 --> 00:28:39.730
Thanks to our live audience who contributed

669
00:28:39.730 --> 00:28:41.890
today. Lovely to hear from you. I think

670
00:28:41.890 --> 00:28:44.450
that's the most active it's ever been. So

671
00:28:44.450 --> 00:28:46.730
it's, uh, value added to the show. We really

672
00:28:46.730 --> 00:28:48.880
appreciate it. And thank you, Fred Watson.

673
00:28:48.880 --> 00:28:51.490
Professor Fred Watson: Uh, as always, it's a pleasure,

674
00:28:51.490 --> 00:28:54.210
Andrew. I hope next time we speak my

675
00:28:54.290 --> 00:28:57.050
knee will be just slightly more tractable

676
00:28:57.050 --> 00:28:59.970
than it is at the moment as the months wear

677
00:28:59.970 --> 00:29:02.610
on and I get back to being 100%

678
00:29:03.090 --> 00:29:05.010
mobile again, which I'm looking forward to.

679
00:29:05.170 --> 00:29:07.250
Andrew Dunkley: Fingers crossed. Good to have you back too.

680
00:29:07.650 --> 00:29:08.130
Professor Fred Watson: Thank you.

681
00:29:08.130 --> 00:29:10.050
Andrew Dunkley: Professor Fred Watson Watson, astronomer at

682
00:29:10.050 --> 00:29:12.170
large. And don't, uh, forget to visit us

683
00:29:12.170 --> 00:29:14.090
online where you can leave questions on the

684
00:29:14.090 --> 00:29:16.930
AMA button at the top. Um, text or audio

685
00:29:16.930 --> 00:29:18.490
questions. Don't forget to tell us who you

686
00:29:18.490 --> 00:29:20.330
are or where you're from and please leave

687
00:29:20.330 --> 00:29:22.590
reviews wherever you listen to us, us. And,

688
00:29:22.820 --> 00:29:24.870
um, have a look around on our website while

689
00:29:24.870 --> 00:29:26.590
you're there and see what else you can find

690
00:29:26.590 --> 00:29:29.070
to, uh, keep you amused between

691
00:29:29.070 --> 00:29:31.710
episodes. And uh, thanks to Huw in the studio

692
00:29:31.710 --> 00:29:34.170
who couldn't be with us today because, um,

693
00:29:34.510 --> 00:29:37.150
like many things in the universe, his

694
00:29:37.150 --> 00:29:40.070
existence is just theoretical. And from me,

695
00:29:40.070 --> 00:29:41.710
Andrew Dunkley, thanks for your company.

696
00:29:42.030 --> 00:29:43.670
We'll see you on the next episode of Space

697
00:29:43.670 --> 00:29:44.270
Nuts.

698
00:29:44.350 --> 00:29:44.670
Andrew Dunkley: Bye.

699
00:29:44.670 --> 00:29:44.990
Generic: Bye.

700
00:29:46.270 --> 00:29:48.470
Andrew Dunkley: You've been listening to the Space Nuts

701
00:29:48.470 --> 00:29:51.460
podcast, mission completed. Available at

702
00:29:51.460 --> 00:29:53.420
Apple Podcasts, Spotify,

703
00:29:53.660 --> 00:29:56.420
iHeartRadio or your favourite podcast

704
00:29:56.420 --> 00:29:58.100
player. You can also stream on

705
00:29:58.100 --> 00:30:00.420
demand@bytes.com this

706
00:30:00.420 --> 00:30:02.740
Professor Fred Watson: has been another quality podcast production

707
00:30:02.740 --> 00:30:04.300
from bytes.com.