Snowball Earth, Dinosaur Asteroids & the Hubble Tension Unravelled

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Andrew Dunkley: Space Nuts is taking a bit of a break at the

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moment. Fred and I will be back in the not

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too distant future with fresh episodes. In

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the meantime, enjoy some of the key episodes

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that we have presented over the years.

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Major events in astronomy and space

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science. And we'll see you real soon.

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Space Nuts. Hi there. Thanks for joining us

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on another episode of Space Nuts. Andrew

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Dunkley here and it's good to have your

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company. Coming up on this episode we're

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going to be looking at Snowball Earth.

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There was a time where it was just a frozen

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sphere of nothingness for well, billions

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of years. now they have a new theory about

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that and it's no Irish joke.

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There's a clue in there. the dinosaur

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asteroids origin has been revealed. Yep, the

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thing that started the getting

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rid of them all across the planet. We know

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where it came from. And the so called

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crisis in cosmology might not be a crisis at

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all. We're talking about the Hubble tension.

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We'll talk about all of that on this episode

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of space nuts. 15 seconds.

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Professor Fred Watson: Guidance is internal. 10, 9.

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ignition sequence start. Space nuts. 5,

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

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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 to help us unravel all of that,

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decipher it and use his code book to

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figure a few more things out, is Professor

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Fred Watson, astronomer at large. Hello Fred.

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Professor Fred Watson: Hello Andrew. Keep up the good work there.

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It's going very well.

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Andrew Dunkley: It's good to see you.

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I just, I thought I'd sort of start out of

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left field because I spotted a

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story, only today actually,

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which dovetails with something we talked

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about some time ago. And that was the work

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that's being done to perfect

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engine technology to achieve greater

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speeds, for interstellar travel

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in years to come. Or maybe not interstellar,

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but interplanetary perhaps. And we know NASA

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is working on this kind of technology to

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create really

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fast and high performance engines. They're

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working with I think it's General Electric to

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achieve that. they may have been Gesumped.

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Fred, have you heard about this?

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Professor Fred Watson: no.

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Andrew Dunkley: the Chinese, the Chinese claim to have

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developed a new engine

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that can achieve a speed of

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12,000 miles per hour

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or 19,700 kilometers an hour.

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And the aircraft can reach an altitude of 30

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kilometers. Now you compare that to the

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Concorde, it's Mach

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16 versus Mach 2, which

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is an extraordinary claim. Now apparently

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they've released a paper which has been peer

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Reviewed, from what I understand. and it's

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not April 1st, I'm confident of that. So

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they reckon that they've, they've made

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this leap in technology to

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develop a Max 16 engine.

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And just think of this, Fred. You'd be able

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to fly from Sydney to New York

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in 50 minutes.

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Professor Fred Watson: Yes, that's what it was, 50 minutes.

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Andrew Dunkley: that's extraordinary if it's real. And I

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don't see why it wouldn't be, but you never

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know with these things. But apparently,

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according to the paper, the engine operates

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in two modes. There's a continuous rotating

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detonation engine, which is a scary thing in

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itself by the sound of it, which will get it

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to Mach 7. And you know, the air and

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the fuel create a rotating shock wave with

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continuous thrust and then a straight line

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oblique detonation engine which

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fires above mark seven and pushes it all

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the way to Mach 16. it

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sounds amazing. Sounds amazing.

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how far short they are of getting this

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into production, I don't know. But, it

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certainly sounds like it's in development.

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That would be amazing to be able to achieve

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those kinds of speeds. it would revolutionize

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travel around the world.

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Professor Fred Watson: But it's been done already.

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Yeah, the British have been working on this

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for decades now with,

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it's an air breathing, it's a hybrid

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engine that breathes air

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at low altitudes and turns into a rocket

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motor when you get above the Earth's

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atmosphere.

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Andrew Dunkley: Yeah, I think I did hear about that. I didn't

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know it got to those sorts of speeds.

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Professor Fred Watson: Yeah, well, it's capable of entering orbit,

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so it can get up to, you know, 26,000

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kilometers an hour. But it's then acting as a

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rocket motor. So it's The project was called,

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well, Hotol was the style of thing,

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horizontal takeoff and landing. so it

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flies like a plane, takes off like a plane

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with the air burning. Jet engines just

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gradually accelerates, clicks, over

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into being a, rocket

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motor, when the atmosphere gets too rarefied

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and then sends you up to orbit. but as

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I remember right, I think it's called the

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Sabre, the engine. If I remember rightly,

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it's Sabre. But the big problem

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was, keeping the air

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cool. And there was some. The

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main breakthrough was apparently a heat

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exchanger that could bring the temperature of

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the air, down from 700

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degrees Celsius or something, to liquid

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nitrogen temperatures in something like a

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thousandth of a second as it passes through

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the engine. and that was a big breakthrough.

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Now I think we've spoken about it before a

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long, long time ago because there hasn't

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really been much news. It was being supported

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by the British government. I don't know

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whether that support has now dwindled,

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because it would be, you know, the idea about

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this was economics. It was to be able to have

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the same spacecraft that will take you up

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there and bring you back and was completely

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reusable. And to some extent I think,

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Elon Musk, SpaceX and their Falcon 9s have

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kind of cornered the market on that because

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they've now got reusable spacecraft which are

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routinely being used every day, almost.

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So maybe there's no space for it. But yeah,

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extraordinary technology and I'm sure the

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Chinese technology is, is above board what

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you've just been describing.

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Andrew Dunkley: Yeah, it's from the Beijing Power Machinery

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Institute and they've published their paper

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in the Chinese Journal of Propulsion

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Technology. I can, I can see a problem with

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it though. Let's say they do create an

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airliner, that can do that trip in 50 minutes

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from New York to Sydney, for example. You'd

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leave at 7 o' clock in the morning in New

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York. You'd arrive at 11pm 50 minutes later

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in Sydney. So you get up

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and get on the plane then get to Sydney and

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then have to go to bed wide away.

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Professor Fred Watson: Yes, that's right.

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That's the issue. It's always the issue.

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Andrew Dunkley: It would make jet lag all the more worse.

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Professor Fred Watson: But you know, I think I'd put up with that

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rather than have all those 20 hours.

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Andrew Dunkley: Yeah, 20 hour flight. Yeah, I've got one of

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those coming up very soon actually.

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Professor Fred Watson: You do, that's right, yeah, yeah, yeah.

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Andrew Dunkley: yeah, to watch this space story, but I just

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find it fascinating these, these kinds of

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leaps in technology.

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Let's move on. a new theory about

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snowball Earth. Fred, I said there's

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there's no Irish joke attached to this and

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there's a good reason I said that.

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Professor Fred Watson: Which I'm probably going to sidestep

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completely. it's about rocks in Scotland and

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in Australia.

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Andrew Dunkley: I thought it was, I thought they said there

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was some of these rocks in Ireland as well.

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Professor Fred Watson: Yeah, I think, I think there are. I think

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that's right. that' think we've got.

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Andrew Dunkley: That's the loose connection I made with.

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Professor Fred Watson: also includes rocks in Namibia, and North

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America, as well as Scotland,

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you're probably right in Ireland because it's

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the west of Scotland where these, where these

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rocks are. That have recently been analyzed.

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and I mean, it's an interesting story. I've

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often wondered about Snowball Earth. I never

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really looked at. At the details of it. So

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it's a period of about 60

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million years ago. Oh, sorry, 60

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million years long. But it was a long

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time ago. It began 700 million years ago,

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in fact, probably more like 720 million

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years ago and lasted until about

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635 million years ago. And it's called

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the cryogenian. Cryogenian geological

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period. And anything with cryo in the front

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of it means it's frozen solid.

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so I thought, well, how do we know this and

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the way we know it and the

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way we know that, glacial ice covered the

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whole planet is because you

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can see in the geology the

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effects of glaciation,

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everywhere. It's not just, you know,

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I grew up in a country where, 10,000 years

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ago, the whole of the northern part of

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Britain was under ice. And so my. All

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my school lessons were about glacial

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features, in the north of England. And

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so, so you could tell from rocks,

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whether something has been glaciated.

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And that's how we know everywhere there is

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this layer of rock, ah, corresponding to,

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looking back, you know, 6, 6 or 700

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million years where you see the evidence of

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glaciation. and so the interpretation of that

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is that, you had an

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ice age that was the. Put it, the

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grandfather of all ice ages. the whole planet

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was frozen. and so

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the new research concerns, evidence from

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rocks in Scotland. and what's

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remarkable is that, the

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sort of the glacial evidence there

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shows up really clearly, for some

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reason that has been preserved very well,

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there, you know, underneath the sediments

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that were dropped on top of it,

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later on. But, the bottom line about.

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Professor Fred Watson: The reason why we got this ice age

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is a question. I'm not sure that in the

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article I sent you, it goes into detail about

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it. but the thinking is that

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we were seeing a period when,

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or before this period, we were seeing a time

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when, volcanic rocks

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were being, eroded. They were being weathered

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very rapidly. And apparently these were

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particularly in Canada. these volcanic rocks,

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I'm looking back now perhaps 720

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million years. they were

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eroded by weathering. And that process

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sucks carbon dioxide out of the atmosphere.

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and so, what you're seeing is

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a situation where the atmospheric

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carbon dioxide is lower

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than normal. And in fact, it is

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probably was probably about half,

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what today's level Is today's level's in

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the region of 400 parts per million of carbon

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dioxide in the atmosphere. And that's enough

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to blanket our planet and keep the

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temperature stable. unless you put more in,

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in which case the temperature goes up, as you

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know. But if, you drop too far down,

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then you get an ice ball. they estimate

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the atmospheric carbon dioxide levels,

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back in the cryogenic period or

261
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cryogenonian period, they estimate

262
00:11:29.272 --> 00:11:31.862
they were below 200 parts per million. And

263
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what that does is lets the heat just radiate

264
00:11:33.942 --> 00:11:36.782
out into the, into space and you

265
00:11:36.782 --> 00:11:39.052
lose heat. The Earth's, surface becomes very

266
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cold. and basically, you get the

267
00:11:41.732 --> 00:11:43.532
snowball Earth, you get an Earth that is

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covered with ice.

269
00:11:46.132 --> 00:11:47.612
it's the same sort of thing that we think

270
00:11:47.612 --> 00:11:49.492
happened on Mars. Mars is very low carbon

271
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dioxide content and that's why we think it

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got cold and dry rather than warm and white

273
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as it once was.

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Andrew Dunkley: The other, there's a lot of moving parts to

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this story, but one of the things I found

276
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most interesting was if this

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mega freeze hadn't happened,

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life as we know it may not have developed

279
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because up until this time it was just

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microbial. Just that was it.

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Professor Fred Watson: That's, that's correct. so, and the thinking,

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yes, it was, it was single celled organisms

283
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until that time. And they were around for

284
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you know, 3 billion years or so.

285
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nothing happened except these single celled

286
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organisms, principally

287
00:12:30.852 --> 00:12:33.412
cyanobacteria, they just did their thing and

288
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got on with life, but didn't evolve in any

289
00:12:35.812 --> 00:12:38.642
way. but the end this,

290
00:12:38.721 --> 00:12:40.802
this end of the glacial period

291
00:12:41.522 --> 00:12:44.522
was such a sort of rapid

292
00:12:44.522 --> 00:12:47.362
climate change by the standards of the,

293
00:12:47.362 --> 00:12:50.182
of the time, by geological standards, that

294
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the thinking is that you'd got almost

295
00:12:53.062 --> 00:12:56.022
an arms race, to adapt,

296
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to this new situation where

297
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the microbes are not permanently in deep

298
00:13:02.972 --> 00:13:05.332
freeze, you've got a warming climate

299
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and the evolution of the microbes kicks in

300
00:13:08.932 --> 00:13:11.172
at a much higher level than it was before.

301
00:13:11.652 --> 00:13:14.182
And that is where we think that the multi

302
00:13:14.182 --> 00:13:16.822
celled organism started to be formed. And

303
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that's what are, the ancestors of all the

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animals that we see today.

305
00:13:20.982 --> 00:13:23.182
Andrew Dunkley: Yeah, so basically those who survived the

306
00:13:23.182 --> 00:13:25.222
thaw or adapted to it,

307
00:13:25.772 --> 00:13:28.252
created life as we know it. Yeah, that's this

308
00:13:28.252 --> 00:13:31.172
extraordinary, sort

309
00:13:31.172 --> 00:13:33.972
of factor to come out of it. The other thing

310
00:13:33.972 --> 00:13:36.932
I, and correct me if I'm wrong, but, these

311
00:13:36.932 --> 00:13:39.092
rocks we were talking about in Ireland and

312
00:13:39.092 --> 00:13:41.532
Scotland and Australia and everywhere else,

313
00:13:41.892 --> 00:13:44.052
the reason that these are so different is I

314
00:13:44.052 --> 00:13:46.852
believe these were rocks that actually stuck

315
00:13:46.852 --> 00:13:49.332
out of the ice. Is that

316
00:13:49.812 --> 00:13:50.372
correct?

317
00:13:51.572 --> 00:13:54.412
Professor Fred Watson: During that period they may have done,

318
00:13:54.412 --> 00:13:57.252
or at least been subject to less

319
00:13:57.572 --> 00:14:00.492
glacial activity. So yes, they may

320
00:14:00.492 --> 00:14:03.012
have, you know, had only a thin layer of ice

321
00:14:03.012 --> 00:14:05.212
over them rather than be under kilometers of

322
00:14:05.212 --> 00:14:08.162
ice. so I think you're right there.

323
00:14:08.162 --> 00:14:11.002
And just to confirm, you're quite

324
00:14:11.002 --> 00:14:12.762
right that some of these rocks are in Ireland

325
00:14:12.762 --> 00:14:15.692
as well. I hadn't spotted that Andrew, in my

326
00:14:15.692 --> 00:14:18.462
reading of the paper. but yes, so you've got,

327
00:14:20.302 --> 00:14:22.812
particularly you've got these rocks

328
00:14:23.132 --> 00:14:26.052
on some of the Scottish islands. These are

329
00:14:26.052 --> 00:14:29.042
small islands called the Gavelis. and it's

330
00:14:28.992 --> 00:14:30.512
basically in the west of Scotland.

331
00:14:32.212 --> 00:14:34.962
it's under the Portaske formation. This is a,

332
00:14:34.962 --> 00:14:37.372
ah, geological area. Portaske, very well

333
00:14:37.372 --> 00:14:38.812
known to Scots people because it's the name

334
00:14:38.812 --> 00:14:41.512
of a well known pipe tune. so let me quote

335
00:14:41.512 --> 00:14:44.442
from one of the authors of this work. and

336
00:14:44.442 --> 00:14:46.442
he's actually a Ph.D.

337
00:14:46.762 --> 00:14:49.212
candidate at the

338
00:14:50.252 --> 00:14:52.552
university, College London. the layers of

339
00:14:52.552 --> 00:14:55.512
rocks exposed on the Gyvelichs are globally

340
00:14:55.512 --> 00:14:58.302
unique. Underneath the rocks laid down during

341
00:14:58.302 --> 00:15:00.982
the unimaginable cold of the glaciation,

342
00:15:01.382 --> 00:15:04.102
70 meters of older carbonate rocks formed

343
00:15:04.182 --> 00:15:06.822
in tropical waters. These layers

344
00:15:06.902 --> 00:15:09.142
record a tropical marine environment with

345
00:15:09.142 --> 00:15:11.262
flourishing cyanobacterial life that

346
00:15:11.262 --> 00:15:13.742
gradually became cooler, marking the end of a

347
00:15:13.742 --> 00:15:16.702
billion years or so of a temperate climate on

348
00:15:16.702 --> 00:15:19.092
Earth. most areas of the world are missing

349
00:15:19.092 --> 00:15:21.252
this remarkable transition because the

350
00:15:21.252 --> 00:15:24.062
ancient glaciers scraped and eroded

351
00:15:24.062 --> 00:15:26.622
the way the rocks underneath. But in

352
00:15:26.622 --> 00:15:28.822
Scotland, by some miracle, the transition can

353
00:15:28.822 --> 00:15:30.912
be seen. And I think that's underlining what

354
00:15:30.912 --> 00:15:32.152
you said. They were either sticking up

355
00:15:32.152 --> 00:15:34.192
through the ice or they weren't particularly

356
00:15:34.352 --> 00:15:37.301
deeply covered by ice. so it's minerals

357
00:15:37.301 --> 00:15:40.202
and radiometric dating of the minerals that

358
00:15:40.282 --> 00:15:43.192
have allowed this discovery to be

359
00:15:43.192 --> 00:15:43.512
made.

360
00:15:44.072 --> 00:15:46.432
Andrew Dunkley: Yeah, it's incredible, isn't it? All the

361
00:15:46.432 --> 00:15:48.352
answers are right there in front of us in the

362
00:15:48.352 --> 00:15:49.352
dirt sometimes.

363
00:15:50.002 --> 00:15:52.002
Professor Fred Watson: Simple as that. That's how we,

364
00:15:52.722 --> 00:15:55.122
we know so much about the history of

365
00:15:55.522 --> 00:15:57.922
not just our planet but the, you know, the,

366
00:15:57.922 --> 00:15:59.882
the other planets of the solar system. Just

367
00:15:59.882 --> 00:16:01.402
learn from looking at the rocks. That's

368
00:16:01.402 --> 00:16:02.722
right, yeah.

369
00:16:02.802 --> 00:16:05.332
Andrew Dunkley: Fantastic. if you'd like to read the article

370
00:16:05.411 --> 00:16:08.362
or chase up that story, it's on the cosmos

371
00:16:08.442 --> 00:16:11.442
magazine.com website. This is

372
00:16:11.442 --> 00:16:13.562
Space Nuts Andrew Dunkley here with Professor

373
00:16:13.562 --> 00:16:14.362
Brad Watson.

374
00:16:17.082 --> 00:16:18.322
Roger, your labs right here.

375
00:16:18.322 --> 00:16:19.802
Professor Fred Watson: Also Space Nuts.

376
00:16:20.102 --> 00:16:23.082
Andrew Dunkley: speaking of dirt, Fred, we've got

377
00:16:23.082 --> 00:16:25.932
the dirt on the dinosaur asteroid. we

378
00:16:25.932 --> 00:16:28.572
now know, thanks to a new study where it came

379
00:16:28.572 --> 00:16:30.692
from. This is fascinating too.

380
00:16:31.412 --> 00:16:33.622
Professor Fred Watson: It is, that's right. and you know, it's not

381
00:16:33.622 --> 00:16:36.182
that long ago that people were really still

382
00:16:36.182 --> 00:16:38.462
speculating about where the remnants of this

383
00:16:38.462 --> 00:16:41.242
asteroid was. we're now pretty certain

384
00:16:41.242 --> 00:16:43.332
that it's in the Chicxulub,

385
00:16:44.022 --> 00:16:46.762
basin in the Gulf of Mexico. That that

386
00:16:46.762 --> 00:16:49.612
is the site which actually was

387
00:16:49.612 --> 00:16:52.492
the impact site of this asteroid. So what

388
00:16:52.492 --> 00:16:55.332
you can do is you can look at the rocks,

389
00:16:55.582 --> 00:16:58.422
that you find in that region. Once again,

390
00:16:58.422 --> 00:17:01.292
we're looking down at the dirt, but

391
00:17:01.292 --> 00:17:03.652
basically look to see whether we know of

392
00:17:03.652 --> 00:17:06.272
anything like it out there

393
00:17:06.432 --> 00:17:09.392
in the solar system. and the

394
00:17:10.672 --> 00:17:13.632
bottom line is that yes, we do find

395
00:17:13.872 --> 00:17:16.612
that, in particular, and this is

396
00:17:16.612 --> 00:17:18.772
work being done at the University of Cologne

397
00:17:18.772 --> 00:17:19.532
in Germany,

398
00:17:21.882 --> 00:17:24.442
the element ruthenium,

399
00:17:25.202 --> 00:17:27.932
is basically a chemical

400
00:17:27.932 --> 00:17:30.922
marker, if I can put it that way, that is

401
00:17:30.922 --> 00:17:33.882
found in the debris around the

402
00:17:33.882 --> 00:17:36.622
Chicxulub impactor, and apparently in

403
00:17:36.622 --> 00:17:38.942
other sediments around the world. Because the

404
00:17:38.942 --> 00:17:40.982
debris from that explosion spread all around

405
00:17:40.982 --> 00:17:43.342
the world. It was so, you know,

406
00:17:44.302 --> 00:17:45.502
ah, such a major

407
00:17:47.342 --> 00:17:49.782
piece of explosive material.

408
00:17:50.262 --> 00:17:52.342
It was only explosive because it hit the

409
00:17:52.342 --> 00:17:55.152
ground at a very high speed, probably 30

410
00:17:55.152 --> 00:17:57.812
or 40 kilometers per second. but the

411
00:17:57.812 --> 00:18:00.252
fingerprint of ruthenium has been found in

412
00:18:00.252 --> 00:18:02.572
that debris and it turns out

413
00:18:03.132 --> 00:18:05.772
that that coincides with

414
00:18:06.092 --> 00:18:08.932
rocks in m, the main

415
00:18:08.932 --> 00:18:11.812
asteroid belt. That's the region between Mars

416
00:18:11.812 --> 00:18:14.732
and Jupiter, but at the outer edge.

417
00:18:15.692 --> 00:18:18.572
Outer, edge of the main asteroid belt. Not

418
00:18:18.572 --> 00:18:20.902
sort of, not the kind of place you'd expect.

419
00:18:20.902 --> 00:18:23.662
You would think if the, if that rock had come

420
00:18:23.662 --> 00:18:25.862
from the asteroid belt, you'd think it would

421
00:18:25.862 --> 00:18:28.142
be near the inner edge. But the chemical

422
00:18:28.562 --> 00:18:30.922
specifics tell you that it's actually at the

423
00:18:30.922 --> 00:18:33.462
outer edge. and that is

424
00:18:34.181 --> 00:18:35.942
really very, very interesting

425
00:18:36.662 --> 00:18:38.952
deduction. Who would have thought that we

426
00:18:38.952 --> 00:18:41.032
will be able to pinpoint where that asteroid

427
00:18:41.032 --> 00:18:43.912
came from, ah, 66 million years after the

428
00:18:43.912 --> 00:18:46.432
event. and maybe the asteroid,

429
00:18:47.712 --> 00:18:48.192
I guess.

430
00:18:48.192 --> 00:18:49.512
Andrew Dunkley: They worked it out on the chemical

431
00:18:49.512 --> 00:18:51.592
composition elements rather than

432
00:18:51.592 --> 00:18:52.512
backtracking.

433
00:18:53.152 --> 00:18:55.822
Professor Fred Watson: Yes, that's right. we don't have enough

434
00:18:55.822 --> 00:18:57.582
information to backtrack. We don't know what

435
00:18:57.582 --> 00:19:00.582
angle it came in at or you know, what its

436
00:19:00.582 --> 00:19:03.222
orbit was before it collided with Earth. So

437
00:19:03.302 --> 00:19:05.392
it's all about chemistry is this. And in

438
00:19:05.392 --> 00:19:06.552
particular some quite

439
00:19:07.862 --> 00:19:09.582
sophisticated, well I suppose you call it

440
00:19:09.582 --> 00:19:11.462
chemical physics because they're using

441
00:19:11.972 --> 00:19:14.862
radiation techniques, basically to

442
00:19:15.342 --> 00:19:17.342
look for these levels of ruthenium,

443
00:19:19.262 --> 00:19:22.062
basically in the debris from the

444
00:19:22.722 --> 00:19:25.052
asteroid, crater and

445
00:19:25.052 --> 00:19:26.672
Surroundings. and,

446
00:19:27.542 --> 00:19:30.542
basically, looking at, how it

447
00:19:30.542 --> 00:19:33.332
compares with other, asteroid

448
00:19:33.332 --> 00:19:35.622
impacts and carbonaceous

449
00:19:35.622 --> 00:19:38.502
meteorites which also come from that

450
00:19:38.502 --> 00:19:40.382
region of the solar system.

451
00:19:41.662 --> 00:19:44.302
Andrew Dunkley: So what might have caused a rock from

452
00:19:44.942 --> 00:19:47.582
that particular part of the solar system to

453
00:19:48.462 --> 00:19:50.741
turn its attention to us? Did Saturn get

454
00:19:50.741 --> 00:19:52.622
upset and chuck a rock at us or something?

455
00:19:56.882 --> 00:19:59.172
Professor Fred Watson: it's probably, a

456
00:20:00.232 --> 00:20:02.912
just a gravitational disturbance, you know,

457
00:20:02.912 --> 00:20:05.752
something that disturbed

458
00:20:05.752 --> 00:20:08.712
the, orbit of this asteroid. in its

459
00:20:08.712 --> 00:20:11.712
comfortable zone of the asteroid belt may be

460
00:20:11.712 --> 00:20:14.232
an interaction with another asteroid. Because

461
00:20:14.232 --> 00:20:16.792
when objects come together, they needn't

462
00:20:16.792 --> 00:20:19.632
necessarily collide. But if they can interact

463
00:20:19.632 --> 00:20:21.592
with each other gravitationally so that one

464
00:20:21.592 --> 00:20:24.512
of them gets thrown out of its orbit

465
00:20:24.512 --> 00:20:26.772
and, you know, it's possible that that would

466
00:20:26.772 --> 00:20:27.572
have been the case.

467
00:20:28.112 --> 00:20:29.762
Andrew Dunkley: it's kind of like being in a crowd at a

468
00:20:29.762 --> 00:20:31.442
Chinese supermarket, really. That's.

469
00:20:32.402 --> 00:20:34.882
Professor Fred Watson: That's what it's like. Yes, yes.

470
00:20:34.882 --> 00:20:37.642
Andrew Dunkley: You didn't want to go that way, but you ended

471
00:20:37.642 --> 00:20:37.922
up.

472
00:20:38.482 --> 00:20:40.402
Professor Fred Watson: You have to. You have to go that way. Yeah.

473
00:20:40.562 --> 00:20:43.282
Just because everything's so crowded. It's

474
00:20:43.362 --> 00:20:46.282
a bit like that. The, the thing is

475
00:20:46.522 --> 00:20:49.442
that that event, whatever tipped it out of

476
00:20:49.442 --> 00:20:52.172
its comfortable orbit, that might have

477
00:20:52.172 --> 00:20:54.932
happened a long time before the 66 million

478
00:20:55.252 --> 00:20:57.572
year date ago,

479
00:20:58.082 --> 00:21:01.042
that we had for the impact for the extinction

480
00:21:01.042 --> 00:21:04.042
of the dinosaurs. So it might have been in an

481
00:21:04.042 --> 00:21:05.882
orbit that intersected the Earth's orbit for

482
00:21:05.882 --> 00:21:08.572
a long, long time, before the

483
00:21:08.572 --> 00:21:10.532
crunch finally came when it tried to be in

484
00:21:10.532 --> 00:21:12.412
the same place at the same time as the Earth.

485
00:21:12.812 --> 00:21:15.612
so. Yes, so there's details for this story

486
00:21:15.612 --> 00:21:18.392
that we still have a long way to finding

487
00:21:18.392 --> 00:21:21.332
out. but it may well have been, as

488
00:21:21.332 --> 00:21:22.972
I said, it's either a collision with another,

489
00:21:23.512 --> 00:21:26.422
asteroid. Or maybe even

490
00:21:26.742 --> 00:21:29.462
something like the gravitational pull of gas

491
00:21:29.462 --> 00:21:30.742
giants, maybe Jupiter,

492
00:21:31.902 --> 00:21:34.782
perturbed that object's orbit in such a

493
00:21:34.782 --> 00:21:36.822
way that it interacted with another asteroid

494
00:21:36.822 --> 00:21:39.032
and got thrown out of, thrown out of the

495
00:21:39.032 --> 00:21:41.122
asteroid belt. We probably will never know

496
00:21:41.122 --> 00:21:43.202
that. It's interesting enough, I think, to

497
00:21:43.282 --> 00:21:44.962
discover whereabouts it came from.

498
00:21:45.602 --> 00:21:47.932
Andrew Dunkley: Yes. The other thing that, came out of this

499
00:21:47.932 --> 00:21:50.252
is that it all but writes off

500
00:21:50.812 --> 00:21:52.412
that this was a comet impact.

501
00:21:52.972 --> 00:21:53.352
Professor Fred Watson: Yes.

502
00:21:53.812 --> 00:21:55.092
Andrew Dunkley: but not absolutely.

503
00:21:56.372 --> 00:21:58.752
Professor Fred Watson: Yeah, that's right. there's still a

504
00:21:58.752 --> 00:22:00.972
possibility, but, you know, comets are, a

505
00:22:00.972 --> 00:22:03.732
different beast from asteroids. They

506
00:22:03.732 --> 00:22:06.682
contain lots of ice, as well as the rock.

507
00:22:06.682 --> 00:22:09.162
And that means that the chemistry of

508
00:22:10.762 --> 00:22:13.122
the residual material from the impact would

509
00:22:13.122 --> 00:22:15.592
have different properties. so I think,

510
00:22:16.172 --> 00:22:18.762
it's, you know, you can never say never,

511
00:22:19.082 --> 00:22:21.842
but the Body of

512
00:22:21.842 --> 00:22:23.602
opinion seems to be that it was actually an

513
00:22:23.602 --> 00:22:25.002
asteroid rather than a comet.

514
00:22:25.322 --> 00:22:28.242
Andrew Dunkley: Yeah. I do have just one more question about

515
00:22:28.242 --> 00:22:30.322
this story and this is the most important one

516
00:22:30.322 --> 00:22:33.222
for it. Most important. You mentioned

517
00:22:33.222 --> 00:22:34.822
the element ruthenium.

518
00:22:36.022 --> 00:22:38.542
So was the person who discovered that named

519
00:22:38.542 --> 00:22:38.982
Ruth?

520
00:22:41.842 --> 00:22:43.492
Professor Fred Watson: that's a good question. I'd have to take that

521
00:22:43.492 --> 00:22:45.502
one unnoticed. But my guess is that that's

522
00:22:45.502 --> 00:22:46.621
where the name came from.

523
00:22:49.422 --> 00:22:51.742
Maybe it was somebody who was ruthless

524
00:22:52.622 --> 00:22:54.702
and they thought, yeah, I'll call it

525
00:22:54.702 --> 00:22:56.902
Ruthenian because I'm ruthless. Who knows

526
00:22:56.902 --> 00:22:57.102
that?

527
00:22:57.102 --> 00:22:59.422
Andrew Dunkley: Yeah, that's a thought too.

528
00:23:00.282 --> 00:23:02.682
that story, if you would like to read it, is

529
00:23:02.762 --> 00:23:05.562
available@spare.com.

530
00:23:06.362 --> 00:23:08.642
this is Space Nuts. Andrew Dunkley here with

531
00:23:08.642 --> 00:23:10.362
Professor Fred Watson.

532
00:23:14.922 --> 00:23:15.962
Professor Fred Watson: Space Nuts.

533
00:23:16.202 --> 00:23:19.032
Andrew Dunkley: now Fred, to the so called crisis in

534
00:23:19.032 --> 00:23:22.022
cosmology. We're talking about, the Hubble

535
00:23:22.022 --> 00:23:24.622
tension. Now we've done this story a few

536
00:23:24.622 --> 00:23:27.062
times over the years. This is where

537
00:23:27.782 --> 00:23:30.542
the, basically the expansion

538
00:23:30.542 --> 00:23:33.312
speed of the universe, depending on how you

539
00:23:33.312 --> 00:23:36.212
calculate, that number comes up with two

540
00:23:36.212 --> 00:23:38.372
different answers. And they have never been

541
00:23:38.372 --> 00:23:41.211
able to figure out why. But now

542
00:23:41.292 --> 00:23:42.852
they're starting to think, well, there's no

543
00:23:42.852 --> 00:23:44.652
crisis at all. Everything's right.

544
00:23:46.542 --> 00:23:48.062
Professor Fred Watson: yes. So,

545
00:23:51.032 --> 00:23:53.952
let me just explain how this tension, the

546
00:23:53.952 --> 00:23:56.712
Hubble tension comes about because

547
00:23:56.952 --> 00:23:58.632
there are two ways of

548
00:23:59.512 --> 00:24:02.492
measuring, the expansion of the

549
00:24:02.492 --> 00:24:05.022
universe. one uses

550
00:24:05.502 --> 00:24:08.022
standard candles and the other uses a

551
00:24:08.022 --> 00:24:10.832
standard ruler. And put it that way.

552
00:24:11.072 --> 00:24:13.712
So the standard candle's taking that first.

553
00:24:13.872 --> 00:24:16.202
if you know how bright your candle is, then

554
00:24:16.202 --> 00:24:18.242
you can work out how far away it is from you.

555
00:24:18.622 --> 00:24:21.502
because, you know, it's real

556
00:24:21.502 --> 00:24:23.582
brightness, it's intrinsic brightness. Then

557
00:24:23.582 --> 00:24:26.062
you can work out what is going on,

558
00:24:26.792 --> 00:24:29.512
in terms of. Because we know the way light

559
00:24:29.592 --> 00:24:32.152
gets fainter, we know the rule by which light

560
00:24:32.152 --> 00:24:34.072
gets fainter as you move to greater and

561
00:24:34.072 --> 00:24:35.632
greater distances. It's what we call the

562
00:24:35.632 --> 00:24:38.212
inverse square law. it goes as the square of

563
00:24:38.212 --> 00:24:40.092
the distance one over the square of the

564
00:24:40.092 --> 00:24:42.992
distance. So, standard candles are usually,

565
00:24:43.902 --> 00:24:46.622
stars in galaxies.

566
00:24:47.322 --> 00:24:50.162
and in fact this is what led us

567
00:24:50.162 --> 00:24:52.842
detect the expansion of the universe in the

568
00:24:52.842 --> 00:24:55.092
first place. Because, in the early years of

569
00:24:55.092 --> 00:24:57.532
the last century, around 1900,

570
00:24:58.032 --> 00:25:00.492
a group of astronomers, in the United

571
00:25:00.652 --> 00:25:03.332
States measured the intrinsic brightness of a

572
00:25:03.332 --> 00:25:05.332
particular kind of variable star, one whose

573
00:25:05.332 --> 00:25:07.992
brightness varies, but it varies in a

574
00:25:07.992 --> 00:25:10.512
periodic way. And it turns out that there's a

575
00:25:10.512 --> 00:25:13.512
relationship between how frequently it varies

576
00:25:13.512 --> 00:25:15.832
and what the intrinsic brightness is. And you

577
00:25:15.832 --> 00:25:17.872
usually take it at peak brightness or minimum

578
00:25:17.872 --> 00:25:19.752
brightness, whichever. It doesn't really

579
00:25:19.752 --> 00:25:22.021
matter as long as you know what it is. and so

580
00:25:22.021 --> 00:25:24.742
that's the time honored way of working out

581
00:25:24.742 --> 00:25:27.712
how far away galaxies are, to look for

582
00:25:27.712 --> 00:25:30.232
these variable stars and then

583
00:25:30.552 --> 00:25:33.532
basically look at, at you

584
00:25:33.532 --> 00:25:35.372
know, how bright they look to us. And from

585
00:25:35.372 --> 00:25:38.302
that work out the distance, and that lets you

586
00:25:38.302 --> 00:25:40.502
produce a value for what we call the Hubble

587
00:25:40.502 --> 00:25:43.302
constant, which is the number that

588
00:25:44.102 --> 00:25:46.502
basically tells you how fast the universe is

589
00:25:46.502 --> 00:25:49.422
expanding. the Hubble constant is

590
00:25:49.422 --> 00:25:51.422
in units of kilometers per second per

591
00:25:51.422 --> 00:25:54.062
megaparsec. But we don't really need to worry

592
00:25:54.062 --> 00:25:55.622
about that because at the moment all we're

593
00:25:55.622 --> 00:25:58.562
interested in is the number. And so until

594
00:25:58.882 --> 00:26:01.802
now, the best estimates, from the

595
00:26:01.802 --> 00:26:03.802
standard candles, in other words, the Cepheid

596
00:26:03.802 --> 00:26:06.762
variables have come, out at

597
00:26:07.032 --> 00:26:09.372
about 74 kilometers per second per

598
00:26:09.372 --> 00:26:12.292
megaparsec. But then the standard ruler

599
00:26:12.292 --> 00:26:14.822
method is looking back at the flash of the

600
00:26:14.822 --> 00:26:16.982
Big Bang, the cosmic microwave background

601
00:26:16.982 --> 00:26:19.902
radiation, which we see, as it was about 13

602
00:26:19.902 --> 00:26:22.832
billion years ago. And there are features in

603
00:26:22.832 --> 00:26:25.212
that variation which have

604
00:26:25.452 --> 00:26:27.892
separations that we know would be

605
00:26:27.892 --> 00:26:29.692
characteristic of a certain

606
00:26:30.812 --> 00:26:32.932
particular time. And what we're talking about

607
00:26:32.932 --> 00:26:35.092
here, when I say features, I mean peaks and

608
00:26:35.092 --> 00:26:37.892
troughs in the temperature of the Big Bang,

609
00:26:37.892 --> 00:26:40.302
effectively what you're looking at. and from

610
00:26:40.302 --> 00:26:42.862
that you can also deduce the Hubble constant,

611
00:26:42.862 --> 00:26:45.672
the expansion rate as it is today. but

612
00:26:45.962 --> 00:26:48.882
the answer you get from that is 67.5

613
00:26:48.882 --> 00:26:51.802
kilometers per second per megaparsec. Yeah.

614
00:26:51.882 --> 00:26:54.402
Which is round about six and a half

615
00:26:54.402 --> 00:26:56.202
kilometers per second per megaparsec,

616
00:26:56.202 --> 00:26:58.642
different from the other one that is now

617
00:26:58.642 --> 00:27:01.402
we're in such a precise era that now

618
00:27:01.402 --> 00:27:04.232
has people worried. so what's

619
00:27:04.232 --> 00:27:06.352
happened? Well, the same team

620
00:27:06.752 --> 00:27:09.112
who've done a huge amount of this work in the

621
00:27:09.112 --> 00:27:11.452
past, led by, Dr. Wendy Freeman

622
00:27:11.642 --> 00:27:14.362
Friedman, one of the big names in this kind

623
00:27:14.362 --> 00:27:17.252
of science in the United States. Wendy

624
00:27:17.252 --> 00:27:20.052
and her team have used our

625
00:27:20.052 --> 00:27:22.772
new toy, the James

626
00:27:22.772 --> 00:27:24.092
Webb Space Telescope.

627
00:27:24.782 --> 00:27:27.262
Andrew Dunkley: we always knew it would solve this problem.

628
00:27:28.062 --> 00:27:30.022
Professor Fred Watson: We knew it would certainly help. It would

629
00:27:30.022 --> 00:27:31.742
either make it worse or it would solve it.

630
00:27:31.742 --> 00:27:33.742
And yeah, you're right. To cut to the chase,

631
00:27:33.742 --> 00:27:35.822
it's probably solved it because it's now

632
00:27:35.822 --> 00:27:38.012
looking as though the

633
00:27:38.892 --> 00:27:41.792
method, is more like that. You know, the

634
00:27:41.792 --> 00:27:43.192
method where you measure the brightness of

635
00:27:43.192 --> 00:27:45.512
these variable stars is giving an answer more

636
00:27:45.512 --> 00:27:48.432
like 70km per second per megaparsec,

637
00:27:48.432 --> 00:27:51.152
which is much closer to that 67.5 that you

638
00:27:51.152 --> 00:27:52.792
get from the cosmic microwave background

639
00:27:52.792 --> 00:27:55.392
radiation. And it turns out that when you

640
00:27:55.392 --> 00:27:58.182
think about the error, potential

641
00:27:58.182 --> 00:28:00.662
error of both of them, then it overlaps.

642
00:28:00.822 --> 00:28:03.362
So in that regard, you've got something that

643
00:28:03.362 --> 00:28:05.242
falls within the error bounds of both of

644
00:28:05.242 --> 00:28:07.962
these methods. And so maybe we are seeing the

645
00:28:07.962 --> 00:28:08.922
right answer at last.

646
00:28:09.002 --> 00:28:11.642
Andrew Dunkley: So it basically brings it back to an average.

647
00:28:12.842 --> 00:28:15.322
Professor Fred Watson: That's right. That's right. Yes.

648
00:28:15.962 --> 00:28:18.842
You know, when I started my career, Andrew,

649
00:28:19.232 --> 00:28:21.082
there were two camps. and

650
00:28:22.042 --> 00:28:24.122
basically they were using similar methods.

651
00:28:24.432 --> 00:28:27.232
one said that the Hubble, constant was

652
00:28:27.232 --> 00:28:29.472
50 kilometers per second per megaparsec. The

653
00:28:29.472 --> 00:28:31.792
other said it was 100 kilometers per second

654
00:28:31.792 --> 00:28:33.672
per megapar a second. They were both right.

655
00:28:34.302 --> 00:28:35.652
they thought they were both right. And, it

656
00:28:35.652 --> 00:28:37.772
turned out that the answer, the real answer

657
00:28:37.772 --> 00:28:40.652
was the average of them. It was 70 or 75 or

658
00:28:40.652 --> 00:28:41.372
thereabouts.

659
00:28:41.932 --> 00:28:44.771
Andrew Dunkley: There you go. pretty simple solution at the

660
00:28:44.771 --> 00:28:47.332
end of the day, but a lot of hard work went

661
00:28:47.332 --> 00:28:48.252
into finding it.

662
00:28:49.052 --> 00:28:51.252
Professor Fred Watson: Yeah, we hope that resolves the Hubble

663
00:28:51.252 --> 00:28:53.532
tension. It will be great. Hopefully cosmic

664
00:28:53.532 --> 00:28:55.662
crisis disappeared. Yeah, Yeah.

665
00:28:55.662 --> 00:28:57.662
Andrew Dunkley: I wouldn't be surprised, though, in months to

666
00:28:57.662 --> 00:28:59.862
come, somebody comes up with a debunking

667
00:28:59.862 --> 00:29:00.262
theory.

668
00:29:01.142 --> 00:29:02.102
Professor Fred Watson: well, there you go.

669
00:29:02.422 --> 00:29:03.222
Andrew Dunkley: It could happen.

670
00:29:03.222 --> 00:29:03.862
Professor Fred Watson: It could happen.

671
00:29:04.972 --> 00:29:07.372
Andrew Dunkley: at this point in time, looks like it might

672
00:29:07.372 --> 00:29:10.092
have been resolved. This has been frustrating

673
00:29:10.092 --> 00:29:12.662
for a long time, but, maybe as simple as. Oh,

674
00:29:12.662 --> 00:29:15.462
hang on a sec. You're both right, and here's

675
00:29:15.462 --> 00:29:17.332
why. Yeah, yeah, yeah. that.

676
00:29:17.332 --> 00:29:18.252
Stories on

677
00:29:18.252 --> 00:29:21.082
scitechdaily.com? without

678
00:29:21.082 --> 00:29:23.002
notice. Fred, that's come through from one of

679
00:29:23.002 --> 00:29:25.002
our live viewers, Wayne. Hi, Wayne.

680
00:29:25.962 --> 00:29:28.132
this harks back to the snowball,

681
00:29:28.562 --> 00:29:31.492
Earth story we did. Wayne asks, I wonder

682
00:29:31.492 --> 00:29:33.772
how much bigger the diameter of a frozen

683
00:29:33.772 --> 00:29:36.492
Earth would be to the current Earth. Do we

684
00:29:36.492 --> 00:29:38.852
have any idea what that might have been?

685
00:29:38.852 --> 00:29:41.372
Professor Fred Watson: Yeah, it probably wasn't that much different.

686
00:29:41.952 --> 00:29:44.732
it, you know, I mean, at the moment,

687
00:29:45.372 --> 00:29:47.252
a lot of that water's still there, but it's

688
00:29:47.252 --> 00:29:50.232
wet and, you know, and this

689
00:29:50.232 --> 00:29:52.712
is. Now it's, it's turned into ice. So,

690
00:29:53.022 --> 00:29:55.142
it's not going to be. It's certainly not

691
00:29:55.142 --> 00:29:57.952
going to be, tens of kilometers different.

692
00:29:58.282 --> 00:30:01.112
it might be a few kilometers different, on

693
00:30:01.112 --> 00:30:02.872
average. And I'm talking about the average.

694
00:30:03.242 --> 00:30:05.112
but, but I don't think it would, you know, it

695
00:30:05.112 --> 00:30:06.552
wouldn't have turned into a gas giant or

696
00:30:06.552 --> 00:30:08.512
anything like that. That's an interesting

697
00:30:08.512 --> 00:30:10.032
question, though, because we think it's

698
00:30:10.032 --> 00:30:12.492
because of frozen water out, in the depths of

699
00:30:12.492 --> 00:30:15.292
the solar system, adding to the mass of the

700
00:30:15.852 --> 00:30:17.972
gas giants as they were being formed. We

701
00:30:17.972 --> 00:30:20.292
think that is one reason why they became so

702
00:30:20.292 --> 00:30:22.972
big because they had enough mass to hold onto

703
00:30:23.132 --> 00:30:25.902
a gas envelope. and so it's a

704
00:30:25.902 --> 00:30:28.382
good question to ask that, ah, what

705
00:30:28.382 --> 00:30:30.662
difference would the ice make? But this is

706
00:30:30.662 --> 00:30:32.982
really just a surface layer of ice rather

707
00:30:32.982 --> 00:30:35.302
than a solid block of ice which may be at the

708
00:30:35.302 --> 00:30:37.142
core of the gas giants.

709
00:30:37.912 --> 00:30:40.072
Andrew Dunkley: Indeed. All right, thank you, Wayne. Nice to

710
00:30:40.072 --> 00:30:42.072
get questions without notice while we're

711
00:30:42.152 --> 00:30:44.472
going out live during our recording sessions.

712
00:30:44.712 --> 00:30:46.742
Good to hear from you, Fred. We're just about

713
00:30:46.742 --> 00:30:47.902
done. Thank you very much.

714
00:30:48.462 --> 00:30:50.442
Professor Fred Watson: A, ah, pleasure, Andrew. Good to talk and,

715
00:30:50.392 --> 00:30:52.231
some interesting topics. And there'll be more

716
00:30:52.231 --> 00:30:52.792
next week.

717
00:30:53.592 --> 00:30:55.582
Andrew Dunkley: Indeed there will. Thanks, Fred. Professor

718
00:30:55.582 --> 00:30:57.342
Fred Watson, astronomer at large. Don't

719
00:30:57.342 --> 00:30:59.182
forget to check us out online

720
00:30:59.182 --> 00:31:02.062
spacenatspodcast.com spacenats IO

721
00:31:02.582 --> 00:31:04.222
where you can check out the shop, maybe

722
00:31:04.222 --> 00:31:06.462
become a supporter of the podcast if you're

723
00:31:06.462 --> 00:31:08.582
interested. just, have a bit of a flick

724
00:31:08.582 --> 00:31:10.942
around. And if you follow us on social media,

725
00:31:10.942 --> 00:31:13.022
don't forget to like us, follow us, add us to

726
00:31:13.022 --> 00:31:15.542
your favorites list, or click the subscribe

727
00:31:15.542 --> 00:31:18.262
button, depending on which platform it is.

728
00:31:18.952 --> 00:31:21.592
and thanks, to Huw in the studio, as always,

729
00:31:21.592 --> 00:31:23.752
and from me, Andrew Dunkley. We will see you

730
00:31:23.752 --> 00:31:26.432
again soon on the very next episode of

731
00:31:26.432 --> 00:31:28.002
SpaceNuts. Bye bye.

732
00:31:29.042 --> 00:31:31.242
You've been listening to the Space Nuts

733
00:31:31.242 --> 00:31:34.202
podcast, available at

734
00:31:34.202 --> 00:31:36.162
Apple Podcasts, Spotify,

735
00:31:36.402 --> 00:31:39.162
iHeartRadio or your favorite podcast

736
00:31:39.162 --> 00:31:40.882
player. You can also stream on

737
00:31:40.882 --> 00:31:43.122
demand@bytes.com this.

738
00:31:43.122 --> 00:31:45.482
Professor Fred Watson: Has been another quality podcast production

739
00:31:45.482 --> 00:31:47.042
from bytes.com.