Cosmic Queries: Weighty Matters, Stellar Ages & Moonless Earth Scenarios

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Andrew Dunkley: Hello again and thank you for joining us.

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This is a Q and A edition of Space Nuts. This

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is where we stand in a queue and go,

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ah. Or not. Um,

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no, it's where we answer audience questions.

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We've got questions today about weight

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variations on Earth, depending on where you

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are. Um, I know we've been down that road

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before, but, um, we're going to do it again.

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Uh, the age of the solar system has been

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brought up again. Visiting, uh, another star.

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Would we be able to do that anytime soon?

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And Earth, uh, minus the moon. A what if

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question that we have done a trillion times.

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But, um, why not? Let's

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reroute to that little, um, what if

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scenario. That's all coming up on this

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edition of space nuts.

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Professor Fred Watson: 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: Space nuts.

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Professor Fred Watson: 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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Professor Fred Watson: Astronauts report it feels good.

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Andrew Dunkley: And he's back again to solve all your

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riddles. It's Professor Fred Watson Watson,

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astronomer at large. Hello, Fred Watson.

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Professor Fred Watson: Hello, Andrew. I'm glad to be a

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riddle solver.

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Andrew Dunkley: Yes, it's a good thing to do, even when you

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can't. You can just pretend. That's what we

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do all the time. I like the Q and

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A edition. It gives us a chance to hear other

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voices from around the world who listen to

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us. And, um, sometimes we learn more about

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them than we expect to. Like, um, Andy the

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train driver in Sydney. And, uh, we've had

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a few over the years. Rusty from Donnybrook,

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one of our regular sender innerers. And,

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um, Sandy in Melbourne and,

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oh, gosh, um, and plenty

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of others. Plenty, uh, of others. And if I

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didn't name you, and I should have, I

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apologise. Martin. We should not, not mention

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Martin.

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Professor Fred Watson: We've got pilots as well.

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Andrew Dunkley: We have. We have Hannah.

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Professor Fred Watson: That's right.

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Andrew Dunkley: Haven't heard from her in ages, but I hope

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she's well. Now, um, let's,

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uh, maybe get to our first question.

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Fred Watson.

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This comes from dj.

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DJ: Hi, guys. DJ from

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Indianapolis, Indiana, usa.

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You, in a recent podcast,

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talked about how if

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a person weighed a hundred kilogrammes

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on the North Pole, that they would weigh

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99 at the equator. My question would

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be, if you were to take a submarine up to the

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North Pole, you pop up through the ice, you

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hop out with your bathroom scale,

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stand on the ice and it says you

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weigh 100 kilogrammes. You take that

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same scale, drive the sub down

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to, say, Ecuador, get out on the

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beach, put your bathroom scale down and now

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would it then say you weighed 99.

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Or are bathroom scales

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calibrated for,

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uh, Earth's gravity at,

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say, the equator? And it would say you

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weighed 99 at the north

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Pole too. Would you need

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scientific instruments to tell the

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difference? Or could a normal person with a

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normal scale tell that they

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weighed a kilogramme less at the pole than

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they do at the equator? Thanks, guys.

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Andrew Dunkley: All right, the first floor in. His question

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is, putting the scales on sand

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would probably completely mess him up. But

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look, we know we get the gist. Um,

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yeah. 100 kilogrammes on the North Pole. Same

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set of scales at the equator. Or

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Ecuador, 99 kilos. Does that sound about

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right?

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Professor Fred Watson: It is. It's perfectly right, yeah. Uh,

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and it would show up on the scale. I mean,

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bathroom scales are notoriously inaccurate.

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They're not accurate to 1%.

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Um, but, but if you did have a really

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accurate scale and you can get them, um,

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then it would show the difference. Uh, it

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would be 100 kilogrammes, uh, on the pole,

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99 at, uh, the equator.

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Um, and that's because what

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you're measuring your weight against is

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something that doesn't change with

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gravity, and that's the spring. Um, you know,

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you're standing on something that's spring

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loaded and the spring behaves the same. No

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matter what gravitational field you're in, it

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still exerts the same force force. And so it

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will feel less weight from you at the

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equator, uh, uh, than it does at, uh, the

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poles. Now,

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um, I think that's fairly common knowledge

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that that happens, that you weigh less.

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Probably most people don't realise that it is

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actually 1%. It's almost exactly 1%, which is

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a bit of a coincidence, uh, but it has

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four sources, uh, not just one.

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So the weight that

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you feel are determined, uh,

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by first of all, the Earth's gravity,

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which is a property of the planet.

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But then you've got the moon's, the sun's

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gravity as well, pulling on you and the

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moon's gravity too. And

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then the thing that I think most people think

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about is the centrifugal force, the fact that

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the Earth is rotating and that gravity gives

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you a centrifugal force that tends to lift

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you a little bit.

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Professor Fred Watson: Um,

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Professor Fred Watson: and that's the case when you look at the

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sun's gravity and the moon's gravity. They're

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basically very, very

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small, uh, and they tend to cancel out.

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Anyway, uh, the

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centrifugal force comes about

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because on the equator, you're travelling at

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1600 kilometres an hour, uh, eastwards,

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and that Motion, because it's in a

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curve, uh, has an acceleration

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represented which cancels out a little bit of

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the gravity. Uh, but the other one is

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the Earth's gravity itself is different.

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Even if the Earth was not rotating, there

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would still be a difference at uh, the

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equator, uh, uh, from the pole. And that's

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because the Earth, uh, is not a perfect

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sphere. It's what we call an oblate spheroid.

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It's slightly flattened. So you're, I can't

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remember how far it is, you're 30 kilometres

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away or something like that, further away at

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the equator, greater from the centre of the

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Earth, uh, uh, than you are,

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uh, the pole. Let me just, I can

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do this in my head. Uh, it's actually

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21 kilometres is the difference.

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You're 21 kilometres further from

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the centre of the Earth when you're on the

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equator than you are at the pole. And that

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means you're higher up until you feel

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slightly less gravity. And when you add that

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to the gravity change you get because of the

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Earth's rotation, it comes to basically 1%.

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Uh, so. Really? Yeah, quite, quite, um, um,

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a nice calculation and also

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quite a nice question from Vijay because

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uh, or DJ I didn't quite catch which.

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Uh, but good to hear from you in Indiana. Uh,

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and it's a well directed question, uh, but

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the answer is yes, you'd see on your bathroom

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scale if it was accurate enough.

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Andrew Dunkley: Yes, uh, we took some bathroom

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scales on a cruise ship once and um, yeah,

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don't use them at sea. I weighed everything

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from 60 to 190 kilos

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in a matter of seconds.

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Uh, it does remind me though of when I was a

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kid. My dad was a pharmacist for his, almost

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his entire career. And back then when

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you didn't have scales at home or you know,

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very few people did, you'd go down to the

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chemist, uh, and you'd put, uh,

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in Australia you'd put 20 cents in the slot

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and stand on the scales and it would give you

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an accurate weight. Wait, last time I used

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one of those I was 11 stone.

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Professor Fred Watson: Yes, things are moving.

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Andrew Dunkley: I still remember 11 stone. Now 11 stone,

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um, doesn't mean much anymore.

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Um, but I'll work it out.

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Equals kilos

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and the answer is 69.85 kilos.

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Well, I weigh a little bit more than that

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now.

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Professor Fred Watson: Probably not that much more.

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Andrew Dunkley: Um, about 15 kilos more.

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Professor Fred Watson: Yeah.

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Andrew Dunkley: 11 stone back in the day. Yes, I was quite

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proud of that. But uh, you don't see them

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anymore, do you, those uh, scales out in

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front of the pharmacies.

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Professor Fred Watson: They used to be. You found them on railway

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stations as well in Britain? I don't know

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why.

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Andrew Dunkley: Yeah, well, they used to have them at

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railway, uh, stations for weighing packages

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and things like that and post offices and

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things. Yeah, yeah, yeah.

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All right, dj, thanks for the question, but,

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yeah, it's true. If you were to take a

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submarine, pop up at the North Pole, put your

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scales down and weigh 100, then go to

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Ecuador and do the same thing, you'd weigh

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99.

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Um, now our next question, Fred Watson. Uh,

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it comes from Nick, uh, who is in

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Cambridge in the uk. He said Cambridge, the

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UK one, just so we didn't get confused with

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Cambridge in the United States. I assume

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there'd probably be more than two. Um, now

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he says, as you answered my previous question

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so eloquently, I came back for a second

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helping. We must have been rude. Wouldn't

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have been you, Fred Watson. Uh, the solar

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system is, uh, 4.6 ish billion

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years old, but it formed from, uh,

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material that is older. Are there any

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estimates for how much older this

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material is? And can this help us date any

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supernovae that may have generated

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it? Uh, or was the solar system formation

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process so energetic that it reset isotope

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ratios, uh, everywhere within the sun's

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sphere of influence, much like heating rocks

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above their Curie point, uh,

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resets isotropic ratios. Thank you for the

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enlightening enlightenment twice a

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week. Uh, it keeps me relatively sane, if you

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can believe it. Nick from Cambridge, the uk,

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one, uh, I like. It's a

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good question. A couple of questions in

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there. So, yeah, um, I

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like where he's going with this.

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Professor Fred Watson: And it's one. I, um, think it's fair to say

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that this is a question still on the front

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line of research, um, because

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when you look through the, you know, the

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astronomical literature, you find a lot of

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stuff about the

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solar nebula. The solar nebula is a cloud of

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gas and dust which, um,

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basically the solar system was born in,

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uh, by this process of gravitational

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collapse. It collapses under

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its own mass, um, and starts spinning and

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you, the spinning produces a disc. So you've

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got a hot ball of gas in the middle, which

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becomes the sun, and this disc of rocky

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material and gaseous material as well

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swirling around it, which is the, um,

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protoplanetary disc. Um, when you look at

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papers, they nearly always

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Professor Fred Watson: commenting, um,

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Professor Fred Watson: on the contents of the solar nebula.

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Just in terms of the mix of gases.

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It's mostly hydrogen and helium with a few

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pollutants, which are, uh, what eventually

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made the rocky planets and the likes of us.

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Um, but there's not that much work done on

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uh, exactly the question that uh,

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Nick is uh, asking. You know, can you

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identify what supernovae

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were? Uh, uh, the

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remnants of their supernovae

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explosions, uh, which

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include heavy elements as well as the

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hydrogen and helium. Can you identify the

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dates of those supernovae? Now I have a

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recollection of seeing some papers that

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refer to evidence

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in uh, meteoritic rock. I think uh,

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that uh, suggests that some of the material

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of the solar system dates from about 8

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billion years ago. Remembering that the age

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of the solar system is more or less 4.6

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billion years, exactly as Nick says. Um,

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and we know it actually a bit more accurately

286
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than that, but that's the easy number to

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remember. 4.6, 4.7 billion years.

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Uh, so yes we do know it formed from material

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that, that's older but I think it's turning

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out to be quite difficult

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science to actually detect that.

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Um, and that may be

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because of the second part of his question.

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Although I suspect that the

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isotope ratios were probably preserved

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rather than destroyed as per the

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Curie point. Um, I'm sorry, this

298
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sounds like a waffly answer but I haven't

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really been able to pin down much research on

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this. There was a spacecraft that

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was launched um, back in, I

302
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think about 2001 that

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uh, it was called Genesis and it was a

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NASA, uh, experiment and the idea was to

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catch particles of the solar wind and bring

306
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them back to Earth. And the solar wind

307
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is basically nuclei of gas,

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they're mostly hydrogen, but you can also

309
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detect any sort of pollutants. And in a

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way what you're trying to do there's is

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analyse remnants

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of the cloud of gas and dust that form

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the solar system. You're trying to analyse

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traces of that gas and dust. And

315
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it's uh, similar to what we do with comets.

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We try and analyse comets to death because we

317
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know they're pristine objects, they've never

318
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been hot, they're just samples of

319
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the solar nebula frozen

320
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onto dust crystals. Uh, but

321
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um, Genesis unfortunately had ah, a problem.

322
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Um, the capsule that was sending

323
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back this material actually um,

324
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the one of the parachutes didn't open and so

325
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it crashed at I think it was 200 kilometres

326
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an hour. It hit the Earth and broke.

327
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Um, so there was some contamination but I

328
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think there was some research done on it but

329
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I don't think they got to the real nub of the

330
00:14:21.920 --> 00:14:24.890
matter. What's the, what's the solar

331
00:14:24.890 --> 00:14:27.770
nebula made of? Um, I'll Keep looking

332
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at this because it is a really interesting

333
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one. And, um, um, you know, if we come

334
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across any more definitive papers, we might

335
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be able to give Nick a shout out later on.

336
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Andrew Dunkley: So he's dug up a mystery, basically.

337
00:14:40.810 --> 00:14:41.850
Professor Fred Watson: Yeah. He's come up with.

338
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Andrew Dunkley: Come up with something we can't quite grapple

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with.

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Professor Fred Watson: That's right. Although I think, as I said,

341
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you know, and unfortunately I've been able to

342
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find the papers that I've read where it does

343
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suggest that we've got evidence for

344
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supernovae in the past, which are, uh, maybe

345
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8 billion years ago, so nearly twice the age

346
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of the solar system. But supernovae in the

347
00:15:01.310 --> 00:15:04.150
environment that we are now in, um, which

348
00:15:04.150 --> 00:15:06.150
would have contributed to the makeup of the

349
00:15:06.150 --> 00:15:08.510
solar system? Good question.

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Andrew Dunkley: It is fascinating. Thank you, Nick. We'll get

351
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back to you shortly. This is Space Nuts with

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Andrew Dunkley and Professor Fred Watson

353
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Watson.

354
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Professor Fred Watson: Step off the land now.

355
00:15:22.820 --> 00:15:25.220
That's one small step for man,

356
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one triumph leap for mankind.

357
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Andrew Dunkley: Space Nuts.

358
00:15:32.580 --> 00:15:32.980
Professor Fred Watson: Yes.

359
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Andrew Dunkley: And you're listening to a Q A edition.

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And our, uh, next question comes from

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Keith.

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Keith: Hey, guys, this is Keith in

363
00:15:41.860 --> 00:15:44.500
Vancouver, Washington, usa,

364
00:15:45.390 --> 00:15:48.350
and I'm just curious about interstellar space

365
00:15:48.430 --> 00:15:51.390
travel. How long do you think it's going to

366
00:15:51.390 --> 00:15:54.270
take for a human to be able to reach

367
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another star? It

368
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seems fairly restrictive with

369
00:16:00.350 --> 00:16:02.350
the distances involved and

370
00:16:03.550 --> 00:16:05.390
you know, what kind of travel

371
00:16:06.590 --> 00:16:08.910
it would take, be it

372
00:16:11.160 --> 00:16:12.680
warp drive or

373
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laser sail. But any, uh, just

374
00:16:18.440 --> 00:16:21.240
curious what you guys think, how long it's

375
00:16:21.240 --> 00:16:23.640
going to take for us to get there and how

376
00:16:23.640 --> 00:16:25.760
realistic it's actually going to be if

377
00:16:25.760 --> 00:16:27.640
anything will ever come of it.

378
00:16:28.600 --> 00:16:30.360
Thanks, guys. Love the podcast.

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00:16:31.240 --> 00:16:32.840
Andrew Dunkley: Thank you, Keith. Great to hear from you.

380
00:16:33.000 --> 00:16:35.440
There's another place that's not where we

381
00:16:35.440 --> 00:16:38.280
would normally think it was. Vancouver. Like

382
00:16:38.280 --> 00:16:40.600
you automatically go, oh, that's Canada. But

383
00:16:40.600 --> 00:16:42.600
no, he's in the U.S. version.

384
00:16:43.590 --> 00:16:46.360
Uh, yes, uh, but Keith, uh, that's a great

385
00:16:46.360 --> 00:16:48.920
question. Um, I suspect it'll be a

386
00:16:48.920 --> 00:16:51.720
spaceship before it is a human being

387
00:16:51.960 --> 00:16:54.800
going to another star system, or another

388
00:16:54.800 --> 00:16:57.200
star for that matter. Uh, the nearest one's

389
00:16:57.200 --> 00:16:59.480
what, Proxima Centauri, which is

390
00:16:59.560 --> 00:17:02.360
4.41 light years away. So,

391
00:17:03.190 --> 00:17:05.800
uh, using conventional engines, you're

392
00:17:05.800 --> 00:17:08.349
looking at a trip of over 6,000

393
00:17:08.509 --> 00:17:08.909
years.

394
00:17:09.229 --> 00:17:10.075
Professor Fred Watson: 60.

395
00:17:10.263 --> 00:17:12.589
Andrew Dunkley: 60,000 years. Yeah, yeah, yeah.

396
00:17:12.909 --> 00:17:14.829
Okay, well, you know, don't forget to take

397
00:17:14.829 --> 00:17:16.909
some eggs, uh, because

398
00:17:19.069 --> 00:17:21.549
they don't keep that long actually. But no,

399
00:17:21.549 --> 00:17:24.469
they don't. It's,

400
00:17:24.469 --> 00:17:26.669
it's a, ah, it's a difficult one and it sort

401
00:17:26.669 --> 00:17:28.149
of goes back to what we were saying in the

402
00:17:28.149 --> 00:17:30.669
previous episode with Elon Musk and, you

403
00:17:30.669 --> 00:17:32.549
know, getting, um, you know, shooting around

404
00:17:32.549 --> 00:17:35.469
all over the solar system, uh, or

405
00:17:35.469 --> 00:17:38.410
all over the galaxy in the. In, um.

406
00:17:38.410 --> 00:17:38.530
Professor Fred Watson: Um.

407
00:17:38.530 --> 00:17:41.450
Andrew Dunkley: It's. It's not probably a high priority

408
00:17:41.770 --> 00:17:44.770
at this stage and I, I think the day will

409
00:17:44.770 --> 00:17:47.450
come where we'll be able to go faster.

410
00:17:47.450 --> 00:17:50.370
But whether or not we can go fast enough to

411
00:17:50.370 --> 00:17:52.970
make a trip to Proxima Centauri,

412
00:17:53.750 --> 00:17:56.010
um, you know, reasonably quick,

413
00:17:56.990 --> 00:17:59.290
uh, like at 99%

414
00:17:59.450 --> 00:18:02.250
relativistic speed, it would

415
00:18:02.250 --> 00:18:03.290
still take you

416
00:18:05.140 --> 00:18:06.500
about three years, I think.

417
00:18:07.670 --> 00:18:10.380
Professor Fred Watson: Uh, well, it would. No, it must be more than

418
00:18:10.380 --> 00:18:10.780
that because.

419
00:18:10.780 --> 00:18:13.580
Andrew Dunkley: No, well, I'm talking. It'd take you

420
00:18:13.580 --> 00:18:15.700
five. I worked it out, actually.

421
00:18:16.980 --> 00:18:19.940
Professor Fred Watson: It would be. Yeah, at light speed, it takes

422
00:18:19.940 --> 00:18:22.180
you 4.3. 4.4 years.

423
00:18:22.420 --> 00:18:22.980
Andrew Dunkley: Yes.

424
00:18:23.070 --> 00:18:26.020
Professor Fred Watson: Uh, and it. But you're right, you've got to

425
00:18:26.020 --> 00:18:26.140
take

426
00:18:26.140 --> 00:18:27.540
Andrew Dunkley: into account time dilation.

427
00:18:28.100 --> 00:18:30.500
Professor Fred Watson: You do. You've got all of that thrown in as

428
00:18:30.500 --> 00:18:30.820
well.

429
00:18:31.140 --> 00:18:31.620
Professor Fred Watson: Yeah.

430
00:18:31.750 --> 00:18:34.120
Professor Fred Watson: Um, and, uh, it's.

431
00:18:34.750 --> 00:18:37.470
Yes, it's hard to envisage,

432
00:18:37.890 --> 00:18:40.750
um, I mentioned in our, uh, last episode

433
00:18:40.750 --> 00:18:42.670
something about some work I'd seen that

434
00:18:42.670 --> 00:18:44.350
suggested that light sails weren't going to

435
00:18:44.350 --> 00:18:46.830
be the answer for this. Because when you get

436
00:18:46.830 --> 00:18:49.390
to high enough speeds, you get this drag,

437
00:18:49.970 --> 00:18:52.750
uh, that actually slows you down and you've

438
00:18:52.750 --> 00:18:55.350
just got to put so much energy into your

439
00:18:55.350 --> 00:18:58.110
laser pointing at the light sails,

440
00:18:58.550 --> 00:19:00.750
uh, that, um, it really

441
00:19:02.030 --> 00:19:04.830
is probably not going to work very well.

442
00:19:07.150 --> 00:19:09.630
Perhaps the nearest we've got to

443
00:19:09.630 --> 00:19:12.270
seriously thinking about interstellar travel

444
00:19:12.910 --> 00:19:15.470
has been the. What was it? Breakthrough

445
00:19:16.430 --> 00:19:18.670
Starshot. Starshot, that's the one.

446
00:19:19.150 --> 00:19:21.750
That project, which was a

447
00:19:21.750 --> 00:19:24.270
feasibility study funded by

448
00:19:24.590 --> 00:19:27.550
a Russian billionaire whose name was on

449
00:19:27.550 --> 00:19:29.070
the tip of my tongue a minute ago, but has

450
00:19:29.070 --> 00:19:31.990
now disappeared, as names tend to do. Milner.

451
00:19:31.990 --> 00:19:33.450
Yuri Milner. That's his name.

452
00:19:33.450 --> 00:19:34.010
Andrew Dunkley: There he is.

453
00:19:34.250 --> 00:19:35.110
Professor Fred Watson: Yeah. Um,

454
00:19:36.710 --> 00:19:39.370
um. Breakthrough Starshot was feasibility

455
00:19:39.450 --> 00:19:42.290
study to see whether we could, within

456
00:19:42.290 --> 00:19:45.290
a kind of human lifetime, and I think they

457
00:19:45.290 --> 00:19:48.130
were thinking of 20 to 30 years, get a

458
00:19:48.130 --> 00:19:50.290
spacecraft to the vicinity of Proxima

459
00:19:50.290 --> 00:19:52.570
Centauri, the nearest star. Uh, yeah.

460
00:19:53.210 --> 00:19:55.290
Andrew Dunkley: Now, interestingly, while you were talking, I

461
00:19:55.290 --> 00:19:58.250
asked, uh, ChatGPT to work it out. And for

462
00:19:58.250 --> 00:20:00.400
people on Earth, at

463
00:20:00.400 --> 00:20:03.240
99%, uh, of light

464
00:20:03.240 --> 00:20:05.480
speed travelling from Earth to Proxima

465
00:20:05.480 --> 00:20:08.310
Centauri, it would be a, um,

466
00:20:08.320 --> 00:20:11.200
4.3 year journey to get there.

467
00:20:11.760 --> 00:20:14.320
However, when you take into account

468
00:20:14.640 --> 00:20:16.960
time dilation, which becomes significant,

469
00:20:17.840 --> 00:20:20.560
the people on board would only

470
00:20:20.560 --> 00:20:23.320
age 7 months is what it's

471
00:20:23.320 --> 00:20:26.240
saying. I think they're missing something.

472
00:20:26.980 --> 00:20:29.370
Professor Fred Watson: Yeah. In, uh, that calculation, um,

473
00:20:29.540 --> 00:20:31.700
it's probably not that

474
00:20:32.260 --> 00:20:35.140
far Off. Yeah, it might not be just

475
00:20:35.140 --> 00:20:35.940
thinking about.

476
00:20:37.700 --> 00:20:40.340
Andrew Dunkley: So the Earth perspective is a 4.3 year

477
00:20:40.340 --> 00:20:42.220
journey. The onboard travellers would

478
00:20:42.220 --> 00:20:43.460
experience seven months.

479
00:20:43.460 --> 00:20:45.380
Professor Fred Watson: It's critically dependent on how near the

480
00:20:45.380 --> 00:20:46.660
speed of light you get to.

481
00:20:47.060 --> 00:20:48.580
Andrew Dunkley: This uh, is at 99%.

482
00:20:48.740 --> 00:20:51.590
Professor Fred Watson: Yes. Yeah. Uh,

483
00:20:51.700 --> 00:20:54.150
so, yeah,

484
00:20:55.270 --> 00:20:57.750
it's kind of roughly something like that. I'm

485
00:20:57.750 --> 00:21:00.710
sure. I always used to use an example of

486
00:21:00.730 --> 00:21:03.670
um, going to a star a thousand light years.

487
00:21:04.070 --> 00:21:06.950
Sorry, a star 500 light years away. So you

488
00:21:06.950 --> 00:21:09.870
make a thousand year journey as elapsed

489
00:21:09.870 --> 00:21:12.870
on Earth and turns out that uh, I

490
00:21:12.870 --> 00:21:15.790
think it's 99.99995% of

491
00:21:15.790 --> 00:21:18.670
the speed of light. Uh, which is almost the

492
00:21:18.670 --> 00:21:20.670
speed of light. But the people on board have

493
00:21:20.670 --> 00:21:23.380
only aged 10 years. So you've got. In 10

494
00:21:23.380 --> 00:21:25.100
years you've gone a thousand years into the

495
00:21:25.100 --> 00:21:26.220
future on Earth.

496
00:21:27.100 --> 00:21:28.940
Andrew Dunkley: Um, it's crazy, isn't it?

497
00:21:28.940 --> 00:21:31.580
Professor Fred Watson: It's bizarre. Yeah, but, but the

498
00:21:31.580 --> 00:21:34.580
physics. So I, you know, as I

499
00:21:34.580 --> 00:21:36.740
said in last week's episode, I think to talk

500
00:21:36.740 --> 00:21:39.059
about interstellar travel, certainly for

501
00:21:39.059 --> 00:21:42.020
humans at the moment physics

502
00:21:42.020 --> 00:21:44.500
just says no way, Jose. It's.

503
00:21:44.500 --> 00:21:47.020
Andrew Dunkley: Yeah, my new book says otherwise.

504
00:21:47.020 --> 00:21:49.100
Professor Fred Watson: But of course it does. Yeah, but that's.

505
00:21:49.180 --> 00:21:51.180
You're in the real world of science fiction.

506
00:21:51.500 --> 00:21:51.980
Andrew Dunkley: Yes.

507
00:21:51.980 --> 00:21:54.680
Professor Fred Watson: Rather, rather than the artificial world of

508
00:21:54.680 --> 00:21:55.710
uh, relativity.

509
00:21:56.110 --> 00:21:59.110
Andrew Dunkley: Yeah. And just uh, to put Keith right in the

510
00:21:59.110 --> 00:22:02.030
picture, um, you know, if you want to get

511
00:22:02.030 --> 00:22:04.750
to light speed, we're a little bit behind at

512
00:22:04.750 --> 00:22:07.310
the moment. Uh, the Parker solar probe

513
00:22:07.710 --> 00:22:10.590
has currently uh, got the um, space

514
00:22:10.750 --> 00:22:11.870
speed record of

515
00:22:11.870 --> 00:22:16.470
0.064%

516
00:22:16.470 --> 00:22:19.230
of the speed of light. So we're nowhere

517
00:22:19.230 --> 00:22:21.740
near 1%. We're nowhere near

518
00:22:21.740 --> 00:22:22.740
0.1%.

519
00:22:24.340 --> 00:22:26.460
Professor Fred Watson: Is it 190 kilometres per second?

520
00:22:26.460 --> 00:22:28.900
Andrew Dunkley: I think it is, yes, yes, give or take.

521
00:22:29.000 --> 00:22:31.380
Um, that's as fast as we've ever been,

522
00:22:31.900 --> 00:22:34.740
um, as a species.

523
00:22:35.460 --> 00:22:38.020
But um, the day will come we'll get faster.

524
00:22:38.660 --> 00:22:40.020
If we could achieve 2%,

525
00:22:41.960 --> 00:22:44.100
um, that would make travelling to the outer

526
00:22:44.100 --> 00:22:45.900
solar system so much quicker.

527
00:22:45.900 --> 00:22:46.900
Professor Fred Watson: Yeah, it would, yes.

528
00:22:46.980 --> 00:22:49.020
Andrew Dunkley: It would take, it would drop the travel time

529
00:22:49.020 --> 00:22:49.540
to weeks.

530
00:22:50.190 --> 00:22:51.150
Professor Fred Watson: Yeah, yeah.

531
00:22:51.150 --> 00:22:53.390
Andrew Dunkley: Would be amazing. So, you know, we don't need

532
00:22:53.390 --> 00:22:56.110
the speed of light yet, but

533
00:22:56.830 --> 00:22:59.720
we do need to probably get a bit quicker. But

534
00:22:59.720 --> 00:23:02.350
uh, yeah, it's an impossible dream at the

535
00:23:02.350 --> 00:23:04.190
moment, Keith, I think would be the answer to

536
00:23:04.190 --> 00:23:07.030
your question. But um, we won't

537
00:23:07.030 --> 00:23:09.910
give up. I'm sure humanity will figure

538
00:23:09.910 --> 00:23:12.590
out a way to do it at some stage.

539
00:23:13.680 --> 00:23:15.390
Uh, but right now if we want to go anywhere,

540
00:23:15.390 --> 00:23:17.390
we've probably got to build a spaceship big

541
00:23:17.390 --> 00:23:19.910
enough for multiple generations to Live on.

542
00:23:20.790 --> 00:23:23.470
By the time they get there, they'll go, can

543
00:23:23.470 --> 00:23:25.790
anyone why we were coming here in the first

544
00:23:25.790 --> 00:23:28.430
place? Like, this place is the pits. Why did

545
00:23:28.430 --> 00:23:29.110
we come here?

546
00:23:30.870 --> 00:23:31.590
Professor Fred Watson: Exactly.

547
00:23:32.390 --> 00:23:34.150
Andrew Dunkley: Thank you, Keith. Great to hear from you.

548
00:23:36.550 --> 00:23:38.630
Professor Fred Watson: 0G and I feel fine.

549
00:23:38.630 --> 00:23:41.230
Andrew Dunkley: Space nuts now, final question comes from

550
00:23:41.230 --> 00:23:44.030
Mark. I love this question because of the

551
00:23:44.030 --> 00:23:46.960
first sentence. Am I the only person

552
00:23:47.040 --> 00:23:50.000
to have watched Space 1999 back in

553
00:23:50.000 --> 00:23:52.680
the 70s? No, you're not, Mark. I was a

554
00:23:52.680 --> 00:23:55.040
huge fan. I loved that show.

555
00:23:55.770 --> 00:23:58.640
Um, it, it was, uh, on.

556
00:23:59.120 --> 00:24:01.320
It was a British show, British, uh, science

557
00:24:01.320 --> 00:24:03.240
fiction TV programme that ran for two

558
00:24:03.240 --> 00:24:05.200
seasons, 75 to 77.

559
00:24:06.130 --> 00:24:08.530
Um, I watched it on Australian, uh,

560
00:24:09.080 --> 00:24:11.680
television and uh, it follows

561
00:24:11.760 --> 00:24:14.690
311 inhabitants of Moon Base

562
00:24:14.690 --> 00:24:17.250
Alpha, which is hurtling uncontrollably into

563
00:24:17.250 --> 00:24:19.970
space due to an explosion of nuclear waste

564
00:24:19.970 --> 00:24:21.730
stored on the moon's far side.

565
00:24:22.930 --> 00:24:25.010
And this is what's prompt Mark's question.

566
00:24:26.280 --> 00:24:28.210
Uh, I clearly remember a big nuclear

567
00:24:28.210 --> 00:24:31.010
explosion in that show. And next

568
00:24:31.010 --> 00:24:33.290
thing, the moon and the inhabitants of the

569
00:24:33.290 --> 00:24:36.010
moon of, uh, Moon Base Alpha are sent off on

570
00:24:36.010 --> 00:24:38.490
their merry way into deep space, leaving the

571
00:24:38.490 --> 00:24:41.450
Earth, uh, to wobble on its axis. On the

572
00:24:41.450 --> 00:24:44.250
bright side, I do like to sail, so

573
00:24:44.250 --> 00:24:46.970
I wouldn't have to worry about tides. So,

574
00:24:47.130 --> 00:24:49.370
you know, that's pretty cool.

575
00:24:49.760 --> 00:24:52.410
Um, what are your thoughts? P.S. i have

576
00:24:52.650 --> 00:24:54.370
cracked, uh, the screen on my phone, so this

577
00:24:54.370 --> 00:24:55.690
might not make much sense.

578
00:24:57.690 --> 00:24:59.410
Keep, uh, doing what you're doing. It brings

579
00:24:59.410 --> 00:25:01.570
me smiles. It brings a smile to my face. That

580
00:25:01.570 --> 00:25:04.170
comes from Mark. Um, so, yeah, all right,

581
00:25:04.170 --> 00:25:06.580
whatever reason, uh, but in this case it was

582
00:25:06.900 --> 00:25:09.600
nuclear waste explosion that sent the, uh,

583
00:25:09.600 --> 00:25:12.100
moon careening off into the heavens and

584
00:25:12.260 --> 00:25:14.420
left Earth all on its lonesome.

585
00:25:15.460 --> 00:25:17.900
Cause and effect. Um, what would be the

586
00:25:17.900 --> 00:25:20.700
effect, uh, as

587
00:25:20.700 --> 00:25:22.700
well, beyond the fact that the oceans would

588
00:25:22.700 --> 00:25:25.020
be much calmer and you could sail quite

589
00:25:25.020 --> 00:25:27.220
happily. Or would they? No,

590
00:25:27.860 --> 00:25:29.460
No, I didn't think so.

591
00:25:29.780 --> 00:25:32.580
Professor Fred Watson: No, I think it's the,

592
00:25:32.610 --> 00:25:35.530
um, it's the currents

593
00:25:35.850 --> 00:25:38.490
in the ocean and the atmosphere

594
00:25:38.570 --> 00:25:41.570
itself that really dictate what's

595
00:25:41.570 --> 00:25:44.330
happening to the surface of the ocean. The

596
00:25:44.330 --> 00:25:47.170
tidal phenomenon is just a really low

597
00:25:47.170 --> 00:25:49.970
frequency effect. Two high tides a

598
00:25:49.970 --> 00:25:52.810
day. Um, and yes, it does

599
00:25:52.810 --> 00:25:54.810
mean water's moving around.

600
00:25:55.610 --> 00:25:58.410
But, uh, the main,

601
00:25:58.680 --> 00:26:01.680
um, kind of source of motion in

602
00:26:01.680 --> 00:26:03.360
the oceans, I think, are these currents that

603
00:26:03.360 --> 00:26:06.320
we're concerned about because the atmosphere

604
00:26:06.320 --> 00:26:09.320
is changing. Uh, oceans are warming up

605
00:26:09.480 --> 00:26:11.410
and some of these currents are, uh,

606
00:26:12.200 --> 00:26:15.000
forecast to possibly switch off, like the one

607
00:26:15.000 --> 00:26:17.680
that's closest to my heart, because it's

608
00:26:17.680 --> 00:26:20.440
where I grew up. But, uh, the Gulf Stream

609
00:26:20.440 --> 00:26:22.840
Drift, which is a Current that comes up from

610
00:26:23.560 --> 00:26:26.520
the. Basically the West Indies, uh,

611
00:26:26.520 --> 00:26:29.090
and crosses the Atlantic and keeps Scotland

612
00:26:29.090 --> 00:26:31.380
warmer than it otherwise would be. Uh,

613
00:26:31.880 --> 00:26:34.450
um, and of course, western England as well,

614
00:26:34.450 --> 00:26:37.250
and Ireland too. But it's why you can

615
00:26:37.250 --> 00:26:39.770
find. When you look down the west coast of

616
00:26:39.770 --> 00:26:42.650
Britain, you can find palm trees, uh, growing

617
00:26:42.650 --> 00:26:44.210
in people's gardens because of that

618
00:26:44.450 --> 00:26:44.970
phenomenon.

619
00:26:44.970 --> 00:26:45.570
Andrew Dunkley: Floated over.

620
00:26:46.290 --> 00:26:49.080
Professor Fred Watson: Something like that. Yeah. Um,

621
00:26:49.170 --> 00:26:52.050
whereas without it, uh, we'd feel

622
00:26:52.130 --> 00:26:54.650
very much more severe winters. Or they would

623
00:26:54.650 --> 00:26:56.730
up there, because I'm now Australian, of

624
00:26:56.730 --> 00:26:59.650
course. Yeah. Oka. Um, so

625
00:27:00.850 --> 00:27:03.090
it's not going to do much to calm the ocean.

626
00:27:03.430 --> 00:27:06.210
Uh, it would get rid of the tides. Um, it

627
00:27:06.210 --> 00:27:09.010
might, as uh, Mark alluded

628
00:27:09.010 --> 00:27:11.650
to in his question, make the Earth wobble on

629
00:27:11.650 --> 00:27:14.370
its axis a bit more. But that would be over

630
00:27:14.690 --> 00:27:17.560
timescales of tens of thousands of years. Um,

631
00:27:17.560 --> 00:27:19.490
and we might be able to cope with that. But,

632
00:27:20.050 --> 00:27:22.090
um, of course we'd miss it because the moon

633
00:27:22.090 --> 00:27:24.770
is very romantic. And, um.

634
00:27:25.140 --> 00:27:27.220
Andrew Dunkley: Yeah, it's a good thing to photograph

635
00:27:27.220 --> 00:27:27.740
sometimes.

636
00:27:27.740 --> 00:27:29.660
Professor Fred Watson: It's great. That's right. It's good to have.

637
00:27:29.660 --> 00:27:30.100
Yeah.

638
00:27:30.740 --> 00:27:33.660
Andrew Dunkley: It wouldn't make life impossible for us if

639
00:27:33.660 --> 00:27:33.940
it.

640
00:27:34.100 --> 00:27:36.500
Professor Fred Watson: No, it wouldn't. Um, it would change life,

641
00:27:36.660 --> 00:27:39.500
definitely. But I mean,

642
00:27:39.500 --> 00:27:41.740
especially the accelerations that it would

643
00:27:41.740 --> 00:27:44.180
produce as it rocketed off into space

644
00:27:44.820 --> 00:27:47.100
might certainly upset things here on Earth.

645
00:27:47.100 --> 00:27:49.380
There'd be a gravitational influence on. That

646
00:27:49.380 --> 00:27:50.660
could change the length of the day.

647
00:27:51.160 --> 00:27:52.840
Andrew Dunkley: Yeah, that's a thought.

648
00:27:54.520 --> 00:27:57.120
Well, um, you know, people working harder and

649
00:27:57.120 --> 00:27:58.960
harder. You'd probably want the day to go

650
00:27:58.960 --> 00:27:59.480
longer,

651
00:28:02.440 --> 00:28:04.480
but I don't know. I don't know what would

652
00:28:04.480 --> 00:28:07.400
happen. It could be interesting, though.

653
00:28:07.880 --> 00:28:09.920
Professor Fred Watson: Well, it could, but, um, hopefully it's not

654
00:28:09.920 --> 00:28:10.440
going to happen.

655
00:28:11.160 --> 00:28:13.480
Andrew Dunkley: No. It is moving away from us though, Mark,

656
00:28:13.640 --> 00:28:16.440
and it will. Yeah, it will

657
00:28:17.280 --> 00:28:19.160
reach a certain distance and then that'll be

658
00:28:19.160 --> 00:28:20.800
it. It'll stop. It's not going to keep going

659
00:28:20.800 --> 00:28:21.040
away.

660
00:28:21.040 --> 00:28:21.680
Professor Fred Watson: That's correct.

661
00:28:21.840 --> 00:28:24.800
Andrew Dunkley: Yeah. But, um. But at the moment we're

662
00:28:24.800 --> 00:28:27.760
stuck with it. Um, that big grey rock that

663
00:28:27.760 --> 00:28:30.360
just sort of looms over us and looks

664
00:28:30.360 --> 00:28:33.160
pretty and, um, lights up the night.

665
00:28:33.160 --> 00:28:33.640
Professor Fred Watson: It's great.

666
00:28:33.640 --> 00:28:36.520
Andrew Dunkley: Yes. May soon have a colony on it. Ben's

667
00:28:36.520 --> 00:28:37.440
really thrilled about that.

668
00:28:39.760 --> 00:28:42.180
Professor Fred Watson: I don't mind a permanent presence, but, um,

669
00:28:42.180 --> 00:28:44.570
the idea of, you know, settling on the moon

670
00:28:44.570 --> 00:28:46.120
is, uh.

671
00:28:46.890 --> 00:28:49.210
Andrew Dunkley: That's Elon's goal now he's given up on Mars.

672
00:28:49.610 --> 00:28:52.490
Professor Fred Watson: Well, yeah, no, he's talking about Mars as

673
00:28:52.490 --> 00:28:53.090
well in the.

674
00:28:53.090 --> 00:28:55.570
Andrew Dunkley: Oh, I know. With the latest. That's the

675
00:28:55.570 --> 00:28:58.450
latest he's still got. Yeah. But I think

676
00:28:58.450 --> 00:29:00.250
he's decided we'll Go to the moon first and

677
00:29:00.250 --> 00:29:02.370
we'll see how we go there. Yeah, Bit worried

678
00:29:02.370 --> 00:29:03.970
about flushing toilets, but we'll figure that

679
00:29:03.970 --> 00:29:04.250
out.

680
00:29:07.370 --> 00:29:09.050
Uh, Mark, thank you. That's a great question.

681
00:29:09.050 --> 00:29:11.770
Lots of fun and, yeah, space 1999,

682
00:29:12.770 --> 00:29:14.530
probably one of the shows that really

683
00:29:14.610 --> 00:29:17.330
switched my brain onto science fiction and I

684
00:29:17.330 --> 00:29:20.050
haven't let go of it. Terrific show.

685
00:29:20.830 --> 00:29:23.050
Uh, that brings us to the end. But if you do

686
00:29:23.050 --> 00:29:25.090
have questions or comments for us, please

687
00:29:25.090 --> 00:29:27.010
visit our website because we'd love to hear

688
00:29:27.010 --> 00:29:28.810
from you. Uh, and if you've thought about

689
00:29:28.810 --> 00:29:30.570
sending in a question and just never got

690
00:29:30.570 --> 00:29:32.930
around to it, well, get around to it.

691
00:29:33.010 --> 00:29:35.138
SpaceNutsPodcast.com SpaceNuts

692
00:29:35.362 --> 00:29:38.250
IO are our URLs because

693
00:29:38.250 --> 00:29:40.850
we got a 2 for 1 package and you can just

694
00:29:40.850 --> 00:29:43.170
press the AMA button at the top, which means

695
00:29:43.170 --> 00:29:45.590
ask me anything and send us your audio or

696
00:29:45.590 --> 00:29:47.510
text questions. Don't forget to tell us who

697
00:29:47.510 --> 00:29:49.110
you are and where you're from. We always like

698
00:29:49.110 --> 00:29:50.590
to know. We've got people all over the place,

699
00:29:50.910 --> 00:29:53.350
but more listeners in Iceland than anywhere.

700
00:29:53.350 --> 00:29:54.630
We're number one in Iceland.

701
00:29:54.630 --> 00:29:55.390
Professor Fred Watson: Woohoo.

702
00:29:56.670 --> 00:29:59.510
Andrew Dunkley: It's very exciting. Um, but I think we're

703
00:29:59.510 --> 00:30:02.270
number two in Australia and number something.

704
00:30:02.590 --> 00:30:05.150
Number nine in America or something.

705
00:30:05.390 --> 00:30:08.110
Professor Fred Watson: Yes, Number five in the uk. I noticed number

706
00:30:08.110 --> 00:30:08.830
five in the uk.

707
00:30:09.310 --> 00:30:10.870
Andrew Dunkley: What happened to the other two people, I

708
00:30:10.870 --> 00:30:13.270
wonder? Anyway, um,

709
00:30:13.610 --> 00:30:15.690
Fred Watson, we've reached the end. Thank you

710
00:30:15.690 --> 00:30:16.170
so much.

711
00:30:16.330 --> 00:30:18.570
Professor Fred Watson: Great pleasure, Andrew. Always good fun.

712
00:30:19.690 --> 00:30:21.730
Andrew Dunkley: And, uh, thanks to Huw in the studio, who

713
00:30:21.730 --> 00:30:23.930
couldn't be with us today, which is why we're

714
00:30:23.930 --> 00:30:25.690
number two in Australia instead of number

715
00:30:25.690 --> 00:30:28.530
one. He just never listens. And from me,

716
00:30:28.530 --> 00:30:30.010
Andrew Dunkley, thanks for your company.

717
00:30:30.010 --> 00:30:31.970
We'll see you on the next episode of Space

718
00:30:31.970 --> 00:30:33.370
Nuts. Bye Bye.

719
00:30:34.570 --> 00:30:36.770
You've been listening to the Space Nuts

720
00:30:36.770 --> 00:30:39.650
podcast, available at

721
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722
00:30:41.960 --> 00:30:44.680
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723
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724
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725
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726
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