Time Travel & Cosmic Questions: The Science Behind Our Universe

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Andrew Dunkley: Hello yet again, this is Space Nuts, a Q and

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A edition. My name is Andrew Dunkley. Thanks

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for joining us and hope you're well wherever

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you are. Could be Yemen, could be the United

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States, the uk, Australia, New Zealand,

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India, Sweden. Uh, I've

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probably missed a couple. Um, uh, one person

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in each country listens to us. So that's yay,

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our entire audience. Uh, on today's

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episode, uh, Andy the train driver in UK has

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got back to us. He's asking a question about

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time travel. Uh, we've also got another

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UK question about orbiting telescopes.

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A, uh, question aimed at, uh, one of the

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things that, uh, most people on Earth love,

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and that is gold, the metal. Uh,

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and we are, uh, getting a what if question

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from Ryan about the sun straying through

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a star forming nebula. What might happen?

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We will tell you what might happen or what

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might not happen. We might not answer any

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questions at all on this episode of

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space nuts. 15 seconds,

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distances internal.

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Professor Fred Watson: 10, 9. Ignition

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sequence start. Uh, space nuts.

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Andrew Dunkley: 5, 4, 3, 2.

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Professor Fred Watson: 1.

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Speaker C: 2, 3, 4, 5, 5, 4, 3, 2,

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1.

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Andrew Dunkley: Space nuts. Astronauts report. It feels

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good. And to help us, uh,

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figure all of that out is Professor

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Fred Watson Watson, astronomena, ah,

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at large. Hello, Fred Watson.

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Professor Fred Watson: I've been described as an astronomist as

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well.

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Andrew Dunkley: Astronomist. I sounded like a Muppet

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then.

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Professor Fred Watson: Yes.

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Andrew Dunkley: Never mind. How are you, Fred Watson?

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Professor Fred Watson: Okay, thank you. Yes, that's good. Recovering

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from my knee surgery. These things

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take time, but, uh, it's going in the right

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direction, which is great.

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Andrew Dunkley: Indeed. Let's, um, let's

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tackle some questions, shall we?

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All right, here we go. Our first one comes

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from Andy.

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Andrew Dunkley: Hi, Andrew and Fred Watson. This is Andy, the

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train driver from London. Uh, hope you're

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both doing well. I hope you also received the

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video I sent you. Um, just a short one, but,

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uh, interesting.

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Time travel and relativistic speeds.

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Um, if I was to travel away from the earth

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for, uh, 100 years at 99.9%

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the speed of light and then turned around and

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came back at the same speed, I would age

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differently to someone that was being left

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behind. Would that be classed as time

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travel? And obviously we haven't got

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the capability, uh, of moving that fast yet.

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But if we did, could we use that to travel

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through time? Thanks guys, Love the

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podcast and see you on the next one.

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Andrew Dunkley: Thanks, Andy. Uh, great to hear from you.

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Yeah, we both got, uh, Andy's video

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and uh, I think we both emailed him back

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about it. But, uh, yeah, he took us for a

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little walk up the railway tracks and showed

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Us, um, the train he was driving

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that day and what it was capable of and was

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really fascinating. So um, yeah, thanks for

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that Andy. It's um, it's nice to see how

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other people work and live and um,

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you know, train driving the different world.

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To me, I've done it once. Um, and

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uh, that was on an old diesel locomotive, um,

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that we, that we went out on one Sunday. That

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was a, it was a vintage um,

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unit. And I got to spend the return trip

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up the front because I was doing uh, doing

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coverage for the ABC at the time. And uh, so

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I uh, I got to do the story Honk the

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Horn. Because in New South Wales,

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nanny, um, state we call it, uh, they have to

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blast the horn at every level crossing

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and you don't know how many there are until

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you have to actually blow the horn every

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time. Uh, it's a safety protocol.

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Um, thanks Andy. Uh, time travel,

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Fred Watson. I love time travel stories or

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questions.

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Professor Fred Watson: Uh, yeah, this is um, the only way that we

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can travel through time. What Andy has

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suggested I used um, to have a

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recipe which I think it meant Visit.

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You go 100, 500 light years

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to a star. You need to travel at 99 point. I

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think it's 9,997% of the speed of

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light for which we don't have the technology

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yet. But if you did, uh, and then came

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back, you would have aged 10 years

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while the planet has aged 1,000

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years. Because you've done two, 500 year

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stints at nearly the speed of light. 500

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light years stints at nearly the speed of

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light. So um, it is a way of

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travelling forward through time. Um,

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as long as you can put up with being

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pushed in a spacecraft that's going to go at

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that sort of rate. And

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that's courtesy of special

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relativity, which is for objects that travel

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near the speed of light. General relativity

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has time dilation as well, uh, for

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objects that um, uh,

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near intense gravitational fields. And I

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think we saw the science fiction version of

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that in interstellar.

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Andrew Dunkley: Yes we did.

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Professor Fred Watson: Which certainly had its, its

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weaknesses in terms of the scientific

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arguments. Um, but, but relativistic

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time travel by speed does work. Uh,

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it's theoretically possible uh, for you to do

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that so you're travelling forward in time.

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What you can't do under really any

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circumstances is go backwards in time. Um,

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there have been people who've looked at the

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prospect from the point of view of um, sort

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of gravitational loops in space time.

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Uh, but if you want to go back in time,

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you've sort of Got to set things up first so

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that the point you go back to, you've got to

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do something, whether it's build a

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gravitational detector or something, you have

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to do something there. And that isn't really

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backward time travel because you've got to

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start with the time that you want to travel

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back to. If I can put it that way.

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Andrew Dunkley: Yeah. Um, and the other problem

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is, uh, you've got to work out where the

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Earth probably would have been at the

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particular point where you want to go.

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Otherwise you'll end up in, you know,

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you'll be in a piece of space that hasn't got

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a planet. Um, yeah,

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there's all sorts of things you need to

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consider.

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Speaker C: Um,

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Andrew Dunkley: I thought I came across an article recently,

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um, that suggested they

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now think backward time travel

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may be plausible. But I can't remember where

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I read it. It might have just been one of

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those speculative articles. It was quite a

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while back that I read it. Didn't see it in

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the news, um, at

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any sort of significant level. But um, yeah,

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um, but yeah, it is possible. Not

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possible, but it is certainly scientifically

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plausible to go forward in time.

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Uh, but you're not really going forward in

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time because your time still remains

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the same according to our clock. It's

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just that because of the speed you're

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travelling, you are not

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ageing as fast as other people.

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Professor Fred Watson: Correct. Uh, what you might call the outside

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observer, you're still ageing at the normal

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rate, but, uh, but you're not.

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Andrew Dunkley: Yeah, you've just wasted a decade proving

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a theory, more or less.

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Professor Fred Watson: Although to go forward a thousand years in

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time might be quite interesting.

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Andrew Dunkley: I suppose. So if you, um. If, yeah, and

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if they ever achieve warp

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technology, um, you could go,

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uh, you could go a hell of a long

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way forward in time, couldn't you?

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Professor Fred Watson: Well, um,

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yeah, if you could warp space so that you

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can, you know, drop through a wormhole or

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something like that. That's a different

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story.

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Andrew Dunkley: Well, that removes the time paradox, doesn't

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it?

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Professor Fred Watson: Yeah. Basically you can take shortcuts

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through space time.

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Andrew Dunkley: That's right, yes, correct. Um, I think we

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had a similar question last week, uh, in

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regard to um, uh, the movie Hail

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Mary project, uh, asking how could

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uh, scientists do 11 light years in

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um, you know, whatever speed he was doing and

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uh, how long would it take him? How much

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younger would he be when he came back, that

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sort of thing. Uh, yeah. And it comes down to

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that time dilation issue, doesn't it?

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Professor Fred Watson: Exactly. That's right. Mhm.

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Andrew Dunkley: All right. Have we answered Andy's question

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because it's very confusing.

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Professor Fred Watson: The answer is yes.

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Andrew Dunkley: Yes, it is. There it is.

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Professor Fred Watson: Yes, Andy, whack your train up to

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99.999% of the speed of light.

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What happens to your passengers?

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Andrew Dunkley: Yeah, especially when you stop fast.

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Yeah, the cabin will get crowded. Um, thanks,

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Andy. Nice to hear from you.

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Now we've got another question, Fred Watson.

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Uh, which I have right in front of me

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here. Hello, Professor Fred Watson and

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Andrew. Thank you for answering my past

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questions. It's always nice to get answers,

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uh, to my incoherent questions this, uh,

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time. My question is about orbiting

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telescopes like Hubble, uh, not SK

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Survey telescopes. Uh, are observations

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planned to minimise the time that the Earth

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is between the telescope and the target?

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Uh, are multiple targets recorded

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concurrently as the telescope whizzes around

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Earth? Is satellite orbit,

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uh, parallax a problem, an advantage, or,

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um, uh, unusually irrelevant

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because space is really, really big.

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It's so big.

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Andrew Dunkley: Yeah.

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Andrew Dunkley: Anyway, uh, and I'm sorry it's three

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questions, but at least they aren't about

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black holes. Thanks for the sterling effort,

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Nick from Cambridge. Uh,

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so, yes, um, Hubble. Um,

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yeah, our observations plan to

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minimise the time that the Earth is between

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the telescope and the target. That's an

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interesting one because, yeah, it is an

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orbiting, uh,

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uh, telescope. Uh, whereas the others are out

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in the L2 Lagrange point. So

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they're not, as they don't have anything

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blocking their view.

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Professor Fred Watson: There are limitations, though, that amount to

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the same thing with the. You can only point

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it in certain directions. Uh, so it means

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during the course of the year you can cover

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the whole sky, but you can't just

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point it randomly in any direction.

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Andrew Dunkley: You got to time it right.

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Professor Fred Watson: Yes, quite so, as with the Hubble as well,

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because, um, what happens when

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time is granted on a telescope like the

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Hubble? Uh, and this is, you know, to the

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applicants who successfully convinced the

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gatekeepers that, uh, their project is worth,

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uh, spending a few hours of Hubble time on.

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Uh, when, when, when those

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observations are brought together, they, they

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fall into the hands of a scheduler. Uh, so

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that they're scheduled for in exactly that

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way. Um, so that they're going to be

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visible when the telescope is

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at that orientation with respect to the

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Earth. Uh, in other words, keep the Earth out

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of the way. So that's certainly the case.

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It's not a random thing. Um, the

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scheduling of space telescopes is very, uh,

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complicated and quite carefully done.

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That was the first question.

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Andrew Dunkley: Are multiple targets recorded concurrently as

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the telescope whizzes around Earth?

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Professor Fred Watson: Um, um,

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the Hubble looks at one thing at a time.

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But yes, if you, if you,

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depending on, you know, where the object

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is in relation to the ah, Earth, you might do

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sort of n seconds of integration on one

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object. N seconds of integration on another.

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And then on the next orbit, repeat that, uh,

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something like that. So that you could. It's

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not concurrently, but it's doing them, you

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know, dovetailing them together so that you

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get the best performance. And I forgot what

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the last question was. I think we might have

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answered it already.

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Andrew Dunkley: Is satellite orbit parallax

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a problem or an advantage or

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irrelevant?

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Professor Fred Watson: Irrelevant. Uh, for most of astronomy, if

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you're looking at the moon, it's not, um, the

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moon is near enough that the parallax

294
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differences caused by, um, the spacecraft

295
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being on one side of the Earth and then on

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the other will be enough. But for pretty well

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everything else, uh, you can ignore it.

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Andrew Dunkley: Okay, interesting. Uh, and of course,

299
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um, yeah, we're sending more and more of

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these, um, things into space. And, um,

301
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the, uh, Vera Rubin is. No,

302
00:12:50.200 --> 00:12:51.040
no, it's the other one.

303
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Professor Fred Watson: Um, uh, the one you're talking about. It's a

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Nancy Grace Roman.

305
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Andrew Dunkley: Nancy Grace Roman has just been, uh,

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launched. So it's, it's heading out. Uh,

307
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and, uh, I think what M is that about 100

308
00:13:01.360 --> 00:13:02.920
days to get there? Something like that.

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Professor Fred Watson: Yes, that's right.

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Andrew Dunkley: So it'd be getting pretty close, wouldn't it?

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Professor Fred Watson: Yes, I think it's. I'm, um, caught up with

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00:13:10.100 --> 00:13:11.620
where it is at the moment. But I think it's

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in good shape and nearly at its, um,

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vantage point.

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Andrew Dunkley: I want to find out now.

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00:13:18.940 --> 00:13:20.620
Professor Fred Watson: Good. Well, tell me when you do.

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Andrew Dunkley: Um, yeah, we'll have a look. Uh,

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00:13:25.370 --> 00:13:27.860
um, so it was launched on the 30th of

319
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August. So, uh, it's probably coming

320
00:13:30.820 --> 00:13:32.540
up on about a third of the way there.

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Professor Fred Watson: Yeah, sounds about right.

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Andrew Dunkley: Yeah. Okay. There you go. Thank you,

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00:13:36.620 --> 00:13:39.180
Nick. Uh, I hope we managed to adequately

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answer your question. That's what we strive

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for here on Space Nuts. A Q and A edition

326
00:13:43.620 --> 00:13:46.060
with Andrew Dunkley and Professor Fred Watson

327
00:13:46.060 --> 00:13:46.820
Watson.

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Okay, Houston, we've had a problem here.

329
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Speaker C: This is Houston.

330
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Andrew Dunkley: Say again, please. Houston, we've had a

331
00:13:54.140 --> 00:13:56.020
problem. We've had a main B plus undervolt.

332
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Roger, main B interval. Okay, standby 13.

333
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We're looking at it. Space butts. Of course,

334
00:14:01.150 --> 00:14:03.350
if you're only. Yes, Earth, Yes.

335
00:14:03.910 --> 00:14:05.760
If you're only half listening to that, um,

336
00:14:05.910 --> 00:14:08.870
that radio call from Apollo 13 about what,

337
00:14:08.870 --> 00:14:11.790
you know, about their main B bus undervolt

338
00:14:11.790 --> 00:14:13.150
problem. You, you Would have thought they

339
00:14:13.150 --> 00:14:16.150
were actually hit by a bus. So,

340
00:14:16.180 --> 00:14:18.650
um, yeah, it can be very confusing. Um,

341
00:14:19.110 --> 00:14:19.510
now.

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Professor Fred Watson: Oh, gosh.

343
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Andrew Dunkley: Uh, Fred Watson, let's, uh, go to our next

344
00:14:22.830 --> 00:14:25.430
question. Uh, this comes from Ash in

345
00:14:25.430 --> 00:14:28.310
Brisbane. Hi, Ash. Uh, I've got a spanner to

346
00:14:28.310 --> 00:14:30.270
throw into the works. In a previous episode,

347
00:14:30.270 --> 00:14:32.970
you mentioned that when neutro stars

348
00:14:32.970 --> 00:14:35.170
collide, the gravity is so extreme that

349
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essentially no debris escapes. Now

350
00:14:37.930 --> 00:14:40.730
here's where my brain started making funny

351
00:14:40.730 --> 00:14:43.410
noises. I'm a bit of a gold

352
00:14:43.490 --> 00:14:46.090
fanatic, and I was under the impression that

353
00:14:46.090 --> 00:14:49.090
regular supernovae aren't energetic enough

354
00:14:49.090 --> 00:14:51.730
to make a heavy, uh, element like gold.

355
00:14:52.210 --> 00:14:54.330
I thought the current thinking is that

356
00:14:54.330 --> 00:14:57.210
neutron star mergers produced much of

357
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the universe's gold. So here is my question.

358
00:14:59.650 --> 00:15:02.370
If no debris escapes a neutron collision,

359
00:15:03.010 --> 00:15:05.790
how did all the gold end up here,

360
00:15:05.950 --> 00:15:08.510
quite literally, uh, for me to admire,

361
00:15:08.510 --> 00:15:10.990
hoard, and dream about buying more of,

362
00:15:11.560 --> 00:15:14.390
uh. Have I misunderstood what nothing escapes

363
00:15:14.390 --> 00:15:16.950
means? Does some material actually get

364
00:15:16.950 --> 00:15:19.750
flung out before the merged objects

365
00:15:19.750 --> 00:15:22.150
settle down? Or have I completely missed a

366
00:15:22.150 --> 00:15:24.950
piece of the puzzle? Love the show and thanks

367
00:15:24.950 --> 00:15:27.070
for feeding my curiosity every week. Looking

368
00:15:27.070 --> 00:15:29.200
forward to hearing your thoughts. Cheers. Uh,

369
00:15:29.200 --> 00:15:31.790
Ash from Brisbane, that is a really good

370
00:15:31.790 --> 00:15:34.490
question. Is there a fundamentally simple

371
00:15:34.490 --> 00:15:34.890
answer?

372
00:15:35.210 --> 00:15:37.610
Professor Fred Watson: Yeah, I think, um, stuff can escape from

373
00:15:38.570 --> 00:15:41.410
a neutron star collision. Maybe I glossed

374
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over something in the past. Um,

375
00:15:44.970 --> 00:15:47.970
I mean, we know neutron star collisions

376
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not only produce, um, a

377
00:15:50.810 --> 00:15:53.610
significant amount of, uh, gravitational

378
00:15:54.090 --> 00:15:56.880
waves, but we also get, um,

379
00:15:56.880 --> 00:15:59.170
electromagnetic radiation from that as well.

380
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So that's something else that can escape. Uh,

381
00:16:02.060 --> 00:16:04.830
and there must be debris, uh,

382
00:16:04.940 --> 00:16:07.900
because otherwise. Exactly. Uh, as Ash

383
00:16:07.900 --> 00:16:10.660
says, uh, you wouldn't get the interstellar

384
00:16:10.660 --> 00:16:13.420
medium being sort of seeded by, uh, by

385
00:16:13.420 --> 00:16:13.740
gold.

386
00:16:16.380 --> 00:16:18.540
Andrew Dunkley: It still makes you wonder like, you know, the

387
00:16:18.540 --> 00:16:21.060
two neutron stars collide, cataclysmic

388
00:16:21.060 --> 00:16:23.100
explosion, stuff gets flung. I mean, they're

389
00:16:23.100 --> 00:16:25.220
not gold bars floating out in space, are

390
00:16:25.220 --> 00:16:28.140
they? So what form does the

391
00:16:28.140 --> 00:16:28.780
gold take?

392
00:16:29.250 --> 00:16:31.970
Professor Fred Watson: It's, It'll be atomic, atomic gold.

393
00:16:32.130 --> 00:16:32.770
Andrew Dunkley: Okay?

394
00:16:32.850 --> 00:16:35.850
Professor Fred Watson: Basically atoms of gold that if you had

395
00:16:35.850 --> 00:16:38.690
enough of them, they'd form a gas. Uh, but

396
00:16:39.490 --> 00:16:42.010
you, um, know, they're. They're probably

397
00:16:42.010 --> 00:16:44.969
quite rarefied. Um, it's.

398
00:16:44.969 --> 00:16:47.610
It. The gold's an interesting one though,

399
00:16:47.610 --> 00:16:50.050
because we think most of the gold on Earth

400
00:16:50.370 --> 00:16:51.930
must have arrived after the Earth's

401
00:16:51.930 --> 00:16:54.730
formation. Because if gold was a

402
00:16:54.730 --> 00:16:56.370
significant proportion of the

403
00:16:57.490 --> 00:16:59.530
gas and dust cloud that the Earth formed from

404
00:16:59.530 --> 00:17:02.100
it, all the gold will be in the middle. It

405
00:17:02.100 --> 00:17:04.500
will be mixed up with the iron core, uh,

406
00:17:05.340 --> 00:17:08.260
because of its mass. So, um, the

407
00:17:08.260 --> 00:17:11.180
thinking is that other objects, like

408
00:17:11.660 --> 00:17:14.500
broken up protoplanets, which would Give rise

409
00:17:14.500 --> 00:17:17.500
to meteorites, uh, and small asteroids.

410
00:17:17.660 --> 00:17:19.540
Those things bombarding the earth are

411
00:17:19.540 --> 00:17:21.380
probably where most of the Earth's gold came

412
00:17:21.380 --> 00:17:23.500
from. But in turn they would have come from,

413
00:17:24.680 --> 00:17:26.130
um, a neutron star collision.

414
00:17:26.439 --> 00:17:26.759
Andrew Dunkley: Yeah.

415
00:17:27.239 --> 00:17:29.879
Professor Fred Watson: They're called kilonovas now, are they,

416
00:17:29.920 --> 00:17:32.599
uh, like a thousand kilo

417
00:17:32.839 --> 00:17:34.839
nova? Ah. Rather than a supernova.

418
00:17:35.399 --> 00:17:37.799
Andrew Dunkley: Wow. Does that make them bigger or just, you

419
00:17:37.799 --> 00:17:40.679
know, nastier? Smaller. Oh, okay. Yeah,

420
00:17:40.679 --> 00:17:42.478
yeah. Super, super bigger. Yeah. Right,

421
00:17:42.478 --> 00:17:45.279
gotcha. Yeah. We're still waiting for the

422
00:17:45.279 --> 00:17:46.279
next big one, aren't we?

423
00:17:47.570 --> 00:17:50.399
Professor Fred Watson: Uh, yes, in terms of, uh, supernovae. That's

424
00:17:50.399 --> 00:17:52.519
right. There's a couple of candidate stars

425
00:17:52.519 --> 00:17:54.719
that might blow their top sometime within the

426
00:17:54.719 --> 00:17:56.620
next few thousand years. Yeah.

427
00:17:57.180 --> 00:17:59.140
Andrew Dunkley: Yeah, we'll have to hang around for that.

428
00:17:59.140 --> 00:18:02.080
It's like m. Yeah. The difference is, um,

429
00:18:02.140 --> 00:18:04.380
between that and waiting for a solar eclipse

430
00:18:04.380 --> 00:18:06.860
is you can get a date for a solar eclipse.

431
00:18:06.860 --> 00:18:08.860
You can't get a date for a supernova.

432
00:18:09.340 --> 00:18:11.420
Professor Fred Watson: 22nd of July, 2028.

433
00:18:11.899 --> 00:18:14.660
Andrew Dunkley: Yes, I know where I'll be. I

434
00:18:14.660 --> 00:18:16.100
don't have to move for once.

435
00:18:16.100 --> 00:18:18.780
Professor Fred Watson: No, you don't. You probably forget and have a

436
00:18:18.780 --> 00:18:20.740
golf match because it's Saturday afternoon.

437
00:18:20.740 --> 00:18:21.580
Andrew Dunkley: Well, it is a Saturday.

438
00:18:21.740 --> 00:18:21.850
Professor Fred Watson: Yeah.

439
00:18:21.850 --> 00:18:23.580
Andrew Dunkley: Ah, but I'm usually finished by then.

440
00:18:25.250 --> 00:18:27.010
I can imagine there'll be people that will be

441
00:18:27.010 --> 00:18:28.930
out there playing that are oblivious to it

442
00:18:29.410 --> 00:18:31.410
and suddenly it'll pitch black.

443
00:18:31.650 --> 00:18:34.010
Professor Fred Watson: We, we hope nobody will be oblivious to it.

444
00:18:34.010 --> 00:18:35.410
That's one of the times that I'm

445
00:18:35.410 --> 00:18:37.010
Andrew Dunkley: pretty sure the news will be significant.

446
00:18:37.410 --> 00:18:39.730
It's already. There's a Facebook page that's

447
00:18:39.730 --> 00:18:42.450
been dedicated to it already, so I've joined

448
00:18:42.450 --> 00:18:44.810
that. And they're constantly. They're already

449
00:18:44.810 --> 00:18:46.290
looking for accommodation. Fred Watson.

450
00:18:46.530 --> 00:18:47.490
Professor Fred Watson: Yeah, there will be.

451
00:18:47.490 --> 00:18:50.420
Andrew Dunkley: Yeah. But, um, yeah, Ash, um,

452
00:18:50.770 --> 00:18:52.930
it's. The stuff does get away.

453
00:18:53.260 --> 00:18:56.150
Um, and, and gold

454
00:18:56.150 --> 00:18:58.390
does end up in space. Gets picked up by the.

455
00:18:58.470 --> 00:19:01.190
Or distributed by the, um,

456
00:19:01.670 --> 00:19:03.910
the debris, I suppose. And some of it ended

457
00:19:03.910 --> 00:19:06.830
up on Earth. Uh, and I still, I

458
00:19:06.830 --> 00:19:09.669
believe still the amount of pure gold

459
00:19:09.669 --> 00:19:12.390
that's been, that's been found. And

460
00:19:12.660 --> 00:19:15.590
um, and, and you know, what do

461
00:19:15.590 --> 00:19:18.550
you call it? Um, refined on Earth still

462
00:19:18.550 --> 00:19:21.410
would only fill. Is it one

463
00:19:21.410 --> 00:19:23.570
or two Olympic size swimming pools.

464
00:19:24.210 --> 00:19:26.850
That's the world's total amount of gold at

465
00:19:26.850 --> 00:19:29.250
the moment. It's not much, is it?

466
00:19:29.890 --> 00:19:32.450
Professor Fred Watson: Not really. No. No, you're right.

467
00:19:32.850 --> 00:19:34.450
I don't think I've got any actually.

468
00:19:34.720 --> 00:19:36.770
Andrew Dunkley: Um. Oh, I've got this.

469
00:19:37.410 --> 00:19:38.890
Professor Fred Watson: All right. Okay, good. Very good.

470
00:19:38.890 --> 00:19:41.410
Andrew Dunkley: That's my grandfather's wedding ring. Uh, my

471
00:19:41.410 --> 00:19:43.090
grandmother gave it to me and said, when you

472
00:19:43.090 --> 00:19:43.650
get married.

473
00:19:44.370 --> 00:19:45.330
Professor Fred Watson: Oh, uh, that's lovely.

474
00:19:45.410 --> 00:19:48.370
Andrew Dunkley: So that ring now has got

475
00:19:49.410 --> 00:19:51.788
80, 40, 50,

476
00:19:51.952 --> 00:19:54.530
57. Oh, hang on, 40. Nearly.

477
00:19:55.570 --> 00:19:57.170
Yeah. 90. 90.

478
00:19:57.330 --> 00:19:57.770
Andrew Dunkley: Nearly.

479
00:19:57.770 --> 00:19:59.650
Andrew Dunkley: 93 years of marriage on it

480
00:20:01.250 --> 00:20:03.170
without. With our, my grandparents.

481
00:20:04.020 --> 00:20:06.650
Um, marriage and, and Judy and I are coming

482
00:20:06.650 --> 00:20:08.530
up on 40 years. Can you believe that?

483
00:20:09.200 --> 00:20:10.210
Professor Fred Watson: Um, no,

484
00:20:12.130 --> 00:20:12.530
Andrew Dunkley: no.

485
00:20:12.930 --> 00:20:13.330
Speaker C: January.

486
00:20:13.330 --> 00:20:14.930
Professor Fred Watson: Think of you as a young couple.

487
00:20:15.010 --> 00:20:17.820
Andrew Dunkley: January, 40 years, marriage. Yeah, it's

488
00:20:18.780 --> 00:20:20.660
hard to get your head around, isn't it? What

489
00:20:20.660 --> 00:20:23.620
have we done with our lives? Uh, anyway, hope

490
00:20:23.620 --> 00:20:24.420
you're doing something good

491
00:20:24.420 --> 00:20:25.600
Professor Fred Watson: for the anniversary, Andrew.

492
00:20:25.600 --> 00:20:28.060
Andrew Dunkley: Uh, we're going to Antarctica.

493
00:20:28.540 --> 00:20:28.940
Professor Fred Watson: Right.

494
00:20:29.340 --> 00:20:31.620
Andrew Dunkley: We wanted to um, put our initials in the

495
00:20:31.620 --> 00:20:31.980
snow,

496
00:20:33.960 --> 00:20:34.900
Professor Fred Watson: um, as you do.

497
00:20:34.900 --> 00:20:36.980
Andrew Dunkley: Yeah, we're not going ashore. We're not doing

498
00:20:36.980 --> 00:20:38.980
that. We're doing the um,

499
00:20:39.340 --> 00:20:41.900
environmentally friendly version of the

500
00:20:41.900 --> 00:20:42.140
train.

501
00:20:42.140 --> 00:20:42.620
Professor Fred Watson: Very good.

502
00:20:42.620 --> 00:20:43.180
Andrew Dunkley: Yeah.

503
00:20:43.820 --> 00:20:45.020
Professor Fred Watson: It's the right thing to do.

504
00:20:45.420 --> 00:20:48.260
Andrew Dunkley: Indeed. Okay. Uh, thanks Ash. Uh, great to

505
00:20:48.260 --> 00:20:50.180
hear from you. Keep collecting the gold and

506
00:20:50.180 --> 00:20:51.820
if you've got any spare, you know where I

507
00:20:51.820 --> 00:20:54.700
live. Uh, our final question, Fred Watson

508
00:20:54.700 --> 00:20:56.510
comes from. Um,

509
00:20:57.580 --> 00:20:59.420
I've got to find it. It's from Ryan.

510
00:20:59.980 --> 00:21:02.540
Speaker C: Hey guys, it's Ryan from Hokassin.

511
00:21:02.540 --> 00:21:05.540
Delaware. Yes, Delaware actually exists. I

512
00:21:05.540 --> 00:21:07.860
have a question and if you would permit me, I

513
00:21:07.860 --> 00:21:10.660
would be interested to hear answers, uh, from

514
00:21:10.660 --> 00:21:13.560
both of you. I recognise

515
00:21:13.560 --> 00:21:16.360
that our solar system and our sun is

516
00:21:16.760 --> 00:21:18.800
rocketing through the universe. Rocketing

517
00:21:18.800 --> 00:21:21.600
around the galaxy. Well, not rocketing, but

518
00:21:21.600 --> 00:21:23.960
you know what I mean. Um, and that currently

519
00:21:24.200 --> 00:21:27.000
our solar system is in what is known as the

520
00:21:27.000 --> 00:21:29.800
local interstellar cloud. It's a

521
00:21:29.880 --> 00:21:32.800
very thin diffuse patch of

522
00:21:32.800 --> 00:21:35.360
gas that we're going through. And the sun's

523
00:21:35.360 --> 00:21:38.200
heliosphere has enough outward pressure to

524
00:21:38.200 --> 00:21:40.200
protect us from this interstellar medium.

525
00:21:41.060 --> 00:21:43.780
My question is, what would happen

526
00:21:43.860 --> 00:21:46.780
if our sun were to stray through a

527
00:21:46.780 --> 00:21:49.700
dense star forming nebula? Something

528
00:21:49.860 --> 00:21:51.780
that has much higher

529
00:21:52.980 --> 00:21:55.460
parts, um, per million or even I don't know

530
00:21:55.780 --> 00:21:58.460
what dense is defined as in a star forming

531
00:21:58.460 --> 00:22:01.220
nebula. Um, but if our sun were to wander

532
00:22:01.220 --> 00:22:03.340
through one of these things, what would

533
00:22:03.340 --> 00:22:05.420
happen to the earth? What would happen to the

534
00:22:05.420 --> 00:22:08.100
heliosphere? What would happen to our solar

535
00:22:08.100 --> 00:22:10.380
system? And again, if you permit me, I'd be

536
00:22:10.380 --> 00:22:13.040
curious to hear the sci fi writer writer on

537
00:22:13.040 --> 00:22:16.040
your show answer first. Thanks so

538
00:22:16.040 --> 00:22:18.400
much guys. Keep uh, up the great work.

539
00:22:18.880 --> 00:22:21.130
Andrew Dunkley: Thank you, Ryan. Uh, I was thinking, um,

540
00:22:21.600 --> 00:22:24.320
Martin Berman Govine could have tackled this

541
00:22:24.320 --> 00:22:26.440
one. But um, he didn't pick up the phone when

542
00:22:26.440 --> 00:22:29.120
I rang. Um, and that's who I

543
00:22:29.120 --> 00:22:30.920
assume he wanted to hear from in terms of

544
00:22:30.920 --> 00:22:32.860
science fiction writers. And um,

545
00:22:33.600 --> 00:22:36.280
I. Look, I did

546
00:22:36.280 --> 00:22:38.960
research this because from a science

547
00:22:38.960 --> 00:22:41.400
fiction point of view I'd like to Think it

548
00:22:41.400 --> 00:22:44.320
would, um, the sun, which means the Earth

549
00:22:44.320 --> 00:22:45.840
and the rest of the solar system would go

550
00:22:45.840 --> 00:22:48.720
with it. Uh, the sun would, uh, start to

551
00:22:48.720 --> 00:22:51.680
fuel itself up on all that, um, meaty

552
00:22:51.680 --> 00:22:54.640
goodness in a nebula. And we

553
00:22:54.640 --> 00:22:57.240
suddenly realise that our life on Earth is

554
00:22:57.240 --> 00:22:59.880
threatened. Significantly, the truth is much

555
00:22:59.880 --> 00:23:02.720
more boring. I'll

556
00:23:02.720 --> 00:23:05.360
let Fred Watson tell the truth, but, um, from

557
00:23:05.360 --> 00:23:07.760
a science fiction perspective, look, it's got

558
00:23:07.760 --> 00:23:10.200
merit. If you wanted to stretch,

559
00:23:11.120 --> 00:23:13.080
um, the truth a very, very.

560
00:23:14.660 --> 00:23:16.540
Not break the rubber band, but, um, you

561
00:23:16.540 --> 00:23:18.500
probably would break the rubber band. But,

562
00:23:18.500 --> 00:23:21.460
uh, I'd go down the line of,

563
00:23:21.480 --> 00:23:23.860
um, yes, if it happened,

564
00:23:24.320 --> 00:23:27.060
uh, the sun would, um, have a

565
00:23:27.060 --> 00:23:29.380
feeding frenzy like a great white shark.

566
00:23:29.860 --> 00:23:32.020
And, uh, Earth would suddenly

567
00:23:32.580 --> 00:23:35.540
risk being gobbled up by what may become

568
00:23:35.540 --> 00:23:38.300
a super sun as a consequence.

569
00:23:38.300 --> 00:23:40.740
But, uh, I just don't believe that's.

570
00:23:41.320 --> 00:23:43.060
That's possible. And, uh,

571
00:23:44.440 --> 00:23:47.080
the chances of this happening, Ryan, are

572
00:23:47.080 --> 00:23:49.680
pretty much nil because the

573
00:23:49.680 --> 00:23:52.570
nearest nebula to Earth, the, uh,

574
00:23:52.640 --> 00:23:55.600
Helix nebula, is about 650 light

575
00:23:55.600 --> 00:23:57.850
years away. So, um,

576
00:23:58.670 --> 00:24:01.520
um, that sort of

577
00:24:01.520 --> 00:24:03.960
puts us out of the realm of possibility. But,

578
00:24:03.960 --> 00:24:06.000
you know, you never know. There might be one

579
00:24:06.000 --> 00:24:08.360
we've missed and is sneaking up on us as we

580
00:24:08.360 --> 00:24:11.080
speak. Time, uh, for you to save this

581
00:24:11.080 --> 00:24:11.880
question, Fred Watson.

582
00:24:12.980 --> 00:24:15.580
Professor Fred Watson: I'm just cheating here because, um, you've

583
00:24:15.580 --> 00:24:17.380
made me think of something I should know.

584
00:24:19.610 --> 00:24:21.860
Uh, so what we're really talking about,

585
00:24:22.340 --> 00:24:25.020
star forming regions are, uh, technically

586
00:24:25.020 --> 00:24:27.910
known as giant molecular clouds. And,

587
00:24:27.910 --> 00:24:30.820
um, the nearest one is 1500 light

588
00:24:30.820 --> 00:24:31.380
years away.

589
00:24:31.380 --> 00:24:32.020
Andrew Dunkley: Oh, there you go.

590
00:24:32.020 --> 00:24:34.660
Professor Fred Watson: Uh, it's the Orion molecular cloud complex.

591
00:24:34.660 --> 00:24:37.220
That makes sense because we know the Orion

592
00:24:37.220 --> 00:24:39.780
Nebula is one of the brightest in the sky.

593
00:24:40.660 --> 00:24:42.820
So giant molecular clouds are indeed where,

594
00:24:43.300 --> 00:24:45.120
uh, star formation is taking taking place.

595
00:24:45.380 --> 00:24:48.160
Um, and the densities there, because

596
00:24:48.160 --> 00:24:50.920
it's a molecular cloud, uh, are higher

597
00:24:50.920 --> 00:24:53.760
than what they would be in the sort of normal

598
00:24:53.760 --> 00:24:56.320
interstellar medium. Um, but

599
00:24:56.560 --> 00:24:59.400
it would be, um. The thing that

600
00:24:59.400 --> 00:25:01.760
would probably make the biggest difference is

601
00:25:01.760 --> 00:25:04.240
that as you approach this thing, and

602
00:25:04.640 --> 00:25:06.440
two people I used to work with at the Royal

603
00:25:06.440 --> 00:25:09.200
Observatory in Edinburgh, um, Victor Klub and

604
00:25:09.200 --> 00:25:12.050
Bill Napier, both theorise

605
00:25:12.050 --> 00:25:14.170
that this has happened in the past, that

606
00:25:14.970 --> 00:25:17.770
a giant molecular cloud passing

607
00:25:18.170 --> 00:25:20.650
close to the solar system would

608
00:25:20.810 --> 00:25:23.770
disturb the Oort cloud to the extent

609
00:25:23.770 --> 00:25:26.330
that you would bombard the inner solar system

610
00:25:26.330 --> 00:25:29.210
with cometary objects. In other words, comet

611
00:25:29.210 --> 00:25:31.810
nuclei coming from the Oort cloud, which we

612
00:25:31.810 --> 00:25:33.650
think is the reservoir of these things at the

613
00:25:33.650 --> 00:25:36.610
edge of the gas cloud that made our own

614
00:25:36.610 --> 00:25:39.590
solar system. So there could be quite

615
00:25:39.590 --> 00:25:42.390
catastrophic, uh, consequences. In

616
00:25:42.390 --> 00:25:45.030
fact, uh, Victor and Bill wrote a book called

617
00:25:45.030 --> 00:25:47.790
the Cosmic Serpent in Which they

618
00:25:48.190 --> 00:25:50.990
equated, if I remember rightly, uh,

619
00:25:51.070 --> 00:25:53.910
some of the um,

620
00:25:53.910 --> 00:25:55.950
geological and

621
00:25:56.710 --> 00:25:59.630
um, mythical, if I can put it that way,

622
00:26:00.070 --> 00:26:02.630
uh, the stories of death and

623
00:26:02.630 --> 00:26:05.390
devastation, um, of which there are

624
00:26:05.390 --> 00:26:07.800
plenty in ancient records. Uh,

625
00:26:08.560 --> 00:26:11.120
those, uh, and the geological

626
00:26:11.600 --> 00:26:14.440
evidence of there having been um, debris

627
00:26:14.440 --> 00:26:16.560
bombarding the earth, uh, they sort of

628
00:26:16.560 --> 00:26:19.240
equated that with the passage of. Potential

629
00:26:19.240 --> 00:26:22.240
passage of known molecular. Giant

630
00:26:22.240 --> 00:26:24.400
molecular clouds. Now their work, that work

631
00:26:24.400 --> 00:26:27.120
was done 70 years, sorry, 50 years ago

632
00:26:27.520 --> 00:26:29.910
or thereabouts. A bit less than that, um,

633
00:26:30.240 --> 00:26:33.160
40 years ago. 46 years ago to

634
00:26:33.160 --> 00:26:35.980
be exact. Um, so things have probably

635
00:26:35.980 --> 00:26:38.380
moved on in terms of what we know about these

636
00:26:38.380 --> 00:26:41.300
things and also about the geological

637
00:26:41.300 --> 00:26:43.500
record too and what the

638
00:26:43.500 --> 00:26:45.700
anthropologists tell us about some of the

639
00:26:46.580 --> 00:26:48.360
um, destruction, uh,

640
00:26:49.100 --> 00:26:51.780
stories, uh, that pervade, uh, ancient

641
00:26:51.780 --> 00:26:54.020
texts of whatever kind they are.

642
00:26:54.420 --> 00:26:56.540
So uh, there might be more to say about that.

643
00:26:56.540 --> 00:26:59.540
But it's still a real phenomenon, potentially

644
00:26:59.620 --> 00:27:02.250
that you could get, um, catastrophic

645
00:27:02.250 --> 00:27:04.410
bombardment of the inner solar system because

646
00:27:04.410 --> 00:27:05.970
of the disturbance, the gravitational

647
00:27:05.970 --> 00:27:08.970
disturbance of a big lump of stuff not very

648
00:27:08.970 --> 00:27:09.690
far away.

649
00:27:09.930 --> 00:27:10.410
Andrew Dunkley: Wow.

650
00:27:10.810 --> 00:27:11.290
Professor Fred Watson: Yeah.

651
00:27:11.290 --> 00:27:12.490
Andrew Dunkley: That's not boring at all.

652
00:27:12.810 --> 00:27:14.530
Professor Fred Watson: No, I don't think it's boring. No, I think

653
00:27:14.530 --> 00:27:14.890
it's.

654
00:27:15.290 --> 00:27:17.890
Andrew Dunkley: Makes a science fiction potential story much

655
00:27:17.890 --> 00:27:18.570
more exciting.

656
00:27:18.570 --> 00:27:21.210
Professor Fred Watson: Yes, well, it does. You could mix the two

657
00:27:21.210 --> 00:27:23.370
together and get a good answer. Probably.

658
00:27:23.770 --> 00:27:24.170
Andrew Dunkley: Good.

659
00:27:24.570 --> 00:27:26.810
Andrew Dunkley: Ryan will be relieved to know that

660
00:27:27.210 --> 00:27:30.150
getting to the um, star forming field

661
00:27:30.150 --> 00:27:32.910
that you uh, brought up, Fred Watson,

662
00:27:32.910 --> 00:27:35.590
1500 light years ago away, will take us

663
00:27:35.990 --> 00:27:38.950
at our current velocity 15 million years.

664
00:27:39.910 --> 00:27:42.750
Professor Fred Watson: Yes, that's probably right. If we were

665
00:27:42.750 --> 00:27:43.750
heading in the right direction.

666
00:27:43.750 --> 00:27:45.189
Andrew Dunkley: If we were heading in the right direction,

667
00:27:45.750 --> 00:27:47.270
that's the other point and we're not.

668
00:27:49.990 --> 00:27:52.950
So I think we're pretty safe at the moment,

669
00:27:52.950 --> 00:27:55.510
Ryan. But thanks, uh, for your thoughts and I

670
00:27:55.510 --> 00:27:57.920
do love the what if questions. That one was

671
00:27:57.920 --> 00:27:59.840
just a little bit out of my realm of

672
00:28:00.400 --> 00:28:02.880
imagination. Um, um, but yeah,

673
00:28:03.430 --> 00:28:05.320
um, but Fred Watson made us feel good by

674
00:28:05.320 --> 00:28:06.560
saying it would be catastrophic.

675
00:28:06.560 --> 00:28:08.720
Professor Fred Watson: Anyway, yes,

676
00:28:10.690 --> 00:28:12.200
Andrew Dunkley: uh, thank you, Ryan. Thank you to everyone

677
00:28:12.200 --> 00:28:14.000
who contributed. And if you've got questions

678
00:28:14.000 --> 00:28:16.800
for us, please send them in to, uh, our

679
00:28:16.800 --> 00:28:19.520
website or via our website, uh, Space Nuts

680
00:28:19.600 --> 00:28:22.280
IO and just click on the AMA button at the

681
00:28:22.280 --> 00:28:24.320
top and uh, you can send text or audio

682
00:28:24.320 --> 00:28:25.840
questions. Don't forget to tell us who you

683
00:28:25.840 --> 00:28:27.410
are and where you're from. We'd be, uh,

684
00:28:27.410 --> 00:28:28.760
thrilled to hear from you. And if you've

685
00:28:28.760 --> 00:28:30.900
never ever sent us a question before, please

686
00:28:30.900 --> 00:28:33.740
do. Um, always looking for newbies.

687
00:28:34.290 --> 00:28:36.460
Uh, we like our regulars too, of course. And

688
00:28:36.510 --> 00:28:38.620
uh, please leave a review wherever you listen

689
00:28:38.620 --> 00:28:40.980
to us or watch us if you watch us. That's.

690
00:28:40.980 --> 00:28:43.260
I'm really sorry about that. But, um, anyway,

691
00:28:43.260 --> 00:28:46.260
that's, you know, head for radio. I've had

692
00:28:46.260 --> 00:28:49.150
it for a long time. I can't change it. Um,

693
00:28:49.150 --> 00:28:50.620
thank you, Fred Watson. We'll see you real

694
00:28:50.620 --> 00:28:50.940
soon.

695
00:28:51.660 --> 00:28:53.900
Professor Fred Watson: I hope so. Yeah. Looking forward to it. Thank

696
00:28:53.900 --> 00:28:54.140
you.

697
00:28:54.620 --> 00:28:55.860
Andrew Dunkley: That's Professor Fred Watson Watson,

698
00:28:55.860 --> 00:28:58.220
Astronomer at large. And thanks to Huw in the

699
00:28:58.380 --> 00:29:00.770
studio who, um, also did some

700
00:29:01.000 --> 00:29:03.800
straying today. Um, like the Earth, um,

701
00:29:04.120 --> 00:29:06.880
or the sun straying through a nebula. He went

702
00:29:06.880 --> 00:29:09.120
straying. So, uh, we haven't seen him for a

703
00:29:09.120 --> 00:29:11.480
couple of months now. And from me, Andrew

704
00:29:11.480 --> 00:29:13.160
Dunkley, thanks for your company. We'll catch

705
00:29:13.160 --> 00:29:15.320
you on the next episode of Space Nuts. Bye.

706
00:29:15.320 --> 00:29:18.240
Bye. You've been listening to

707
00:29:18.240 --> 00:29:19.720
the Space Nuts podcast,

708
00:29:21.320 --> 00:29:24.120
available at Apple Podcasts, Spotify,

709
00:29:24.280 --> 00:29:26.570
iHeartRadio or your favourite, favourite

710
00:29:26.570 --> 00:29:28.570
podcast player. You can also stream

711
00:29:28.570 --> 00:29:30.450
ondemand@bytes.com.

712
00:29:30.770 --> 00:29:32.850
Professor Fred Watson: this has been another quality podcast

713
00:29:32.850 --> 00:29:34.450
production from Bytes.

714
00:29:34.610 --> 00:29:34.650
Speaker C: Com.

715
00:29:34.650 --> 00:29:34.670
Andrew Dunkley: Um,