Latest / Space Nuts: Astronomy Insights & Cosmic Discoveries / #445: Snowball Earth Theories, Dinosaur Asteroid Origins, and the Hubble Tension Resolved

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#445: Snowball Earth Theories, Dinosaur Asteroid Origins, and the Hubble Tension Resolved · Space Nuts: Astronomy Insights & Cosmic Discoveries

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  Speaker 1: Hi there, thanks for joining us on another episode of
• 0:02
  Speaker 1: Space Nuts. Andrew Dunkley here, and it's good to have
• 0:05
  Speaker 1: your company. Coming up on this episode, we're going to
• 0:09
  Speaker 1: be looking at Snowball Earth. There was a time where
• 0:12
  Speaker 1: it was just a frozen sphere of nothingness for well
• 0:17
  Speaker 1: billions of years. Now they have a new theory about that,
• 0:20
  Speaker 1: and it's no Irish joke. There's a clue in there.
• 0:24
  Speaker 1: The dinosaur asteroid's origin has been revealed. Yep, the thing
• 0:29
  Speaker 1: that started the getting rid of them all across the planet.
• 0:33
  Speaker 1: We know where it came from. And the so called
• 0:37
  Speaker 1: crisis in cosmology might not be a crisis at all.
• 0:40
  Speaker 1: We're talking about the hubble tension. We'll talk about all
• 0:43
  Speaker 1: of that on this episode of Space Nuts fifteen in
• 0:48
  Speaker 1: Channel ten nine ignition sequence Space Nuts or three.
• 0:56
  Speaker 2: Two review on space as When I report it, Neils
• 1:02
  Speaker 2: good and.
• 1:03
  Speaker 1: To help us unravel all of that, decipher it and
• 1:08
  Speaker 1: use his codebook to figure a few more things out,
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  Speaker 1: is professor I've Fred what's an astronomer at large? Hello Fred,
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  Speaker 1: Hello Andrew, keep up the good work there.
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  Speaker 2: It's going very well.
• 1:18
  Speaker 1: It's good to see you now. I just I thought
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  Speaker 1: i'd sort of start out a left field because I
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  Speaker 1: spotted a story only today actually which dovetails with something
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  Speaker 1: we talked about some time ago, and that was the
• 1:34
  Speaker 1: work that's being done to perfect engine technology to achieve
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  Speaker 1: greater speeds for interstellar travel in years to come, or
• 1:45
  Speaker 1: maybe not interstellar but into planetary perhaps. And we know
• 1:48
  Speaker 1: NASA is working on this kind of technology to create
• 1:54
  Speaker 1: really fast and high performance engines. They're working with I
• 1:59
  Speaker 1: think it's general electric to achieve that. They may have
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  Speaker 1: been gazumped, Fred, have you heard about this?
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  Speaker 2: Uh?
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  Speaker 1: No, the Chinese. The Chinese claim to have developed a
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  Speaker 1: new engine that can achieve a speed of twelve thousand
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  Speaker 1: miles per hour or nineteen seven hundred kilometers an hour,
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  Speaker 1: and the aircraft can reach an altitude of thirty kilometers.
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  Speaker 1: Now you compare that to the concord. It's Mac sixteen
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  Speaker 1: versus Mac two, which is an extraordinary claim. Now, apparently
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  Speaker 1: they've released a paper which has been peer reviewed from
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  Speaker 1: what I understand, and it's not April or first, I'm
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  Speaker 1: confident of that. So they reckon that they've made this
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  Speaker 1: leap in technology to develop a Mac sixteen engine, And
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  Speaker 1: just think of this thread, you'd be able to fly
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  Speaker 1: from Sydney to New York in fifty minutes.
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  Speaker 2: Yes, fifty minutes.
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  Speaker 1: That's extraordinary if it's real, and I don't see why
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  Speaker 1: it wouldn't be, but you never know with these things.
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  Speaker 1: But apparently, according to the paper, the engine operates in
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  Speaker 1: two modes. There's a continuous rotating detonation engine, which is
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  Speaker 1: a scary thing in itself by the sound of it,
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  Speaker 1: which will get it to mark seven and the air
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  Speaker 1: and the fuel create a rotating shockwave with continuous thrust.
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  Speaker 1: And then a straight line oblique detonation engine which fires
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  Speaker 1: above mark seven and pushes it all the way to
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  Speaker 1: mark sixteen. It sounds amazing, sounds amazing. How far short
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  Speaker 1: they are of getting this into production, I don't know,
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  Speaker 1: but it certainly sounds like it's in development. That would
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  Speaker 1: be amazing to be able to achieve those kinds of speeds.
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  Speaker 1: It would revolutionize travel around the world.
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  Speaker 2: It's been done already by yeah, the British have been
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  Speaker 2: working on this for decades now. With then it's an
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  Speaker 2: air breathing It's a hybrid engine that breathes there at
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  Speaker 2: low altitudes and turns into a rocket motor when you
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  Speaker 2: get above the atmosphere.
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  Speaker 1: Yeah, I think I did hear about that. I did
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  Speaker 1: not go to those sort of space.
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  Speaker 2: Yeah, well it can. It's capable of entering orbit, so
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  Speaker 2: it can get up to you know, twenty six thousand
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  Speaker 2: kilometers an hour. But it's then acting as a rocket motor,
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  Speaker 2: so it's the project was called well hotel was the
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  Speaker 2: style of thing, horizontal takeoff and landing, so it flies
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  Speaker 2: like a plane, takes off like a plane with the
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  Speaker 2: air burning jet engines, just gradually accelerates, clicks over into
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  Speaker 2: being a rocket motor when the atmosphere gets too rarefied,
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  Speaker 2: and then sends you up to orbit. As I remember right,
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  Speaker 2: I think it's called the saber the engine if I
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  Speaker 2: remember righter. But the big problem was keeping the air cool,
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  Speaker 2: and there was some The main breakthrough was apparently a
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  Speaker 2: heat ex changer that could bring the temperature of the
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  Speaker 2: air down from seven hundred degrees celsius or something to
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  Speaker 2: liquid nitrogen temperatures in something like a thousandth of a
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  Speaker 2: second as it passes through the engine, And that was
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  Speaker 2: a big breakthrough. Now we've I think we've spoken about
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  Speaker 2: it before a long long time ago, because I haven't
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  Speaker 2: really been much News. It was being supported by the
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  Speaker 2: British government. I don't know whether that support has now dwindled,
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  Speaker 2: because it would be you know, the idea about this
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  Speaker 2: was economics. It was to be able to have the
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  Speaker 2: same spait spacecraft that will take you up there and
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  Speaker 2: bring you back and was completely reusable. And to some extent,
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  Speaker 2: I think Elon Musk's Base X and the Falcon Nines
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  Speaker 2: have kind of cornered the market on that because they've
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  Speaker 2: now got reusable spacecraft which are routinely being used every
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  Speaker 2: day almost so maybe there's no space for it. But yeah,
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  Speaker 2: extraordinary technology, and I'm sure the Chinese technology is above
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  Speaker 2: board what you've just been describing.
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  Speaker 1: Yeah, it's from the Beijing Power Machinery Institute and they've
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  Speaker 1: published their paper in the Chinese Journal of Propulsion Technology.
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  Speaker 1: I can see a problem with it, though. Let's say
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  Speaker 1: they do create an airliner that can do that trip
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  Speaker 1: in fifty minutes from New York to Sydney. For example,
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  Speaker 1: you'd leave at seven o'clock in the morning in New York.
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  Speaker 1: You'd arrive at eleven pm fifty minutes later in Sydney.
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  Speaker 1: So you get up and get on the plane and
• 6:40
  Speaker 1: then get the Sydney and then have to go to
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  Speaker 1: bed right away.
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  Speaker 2: Yes, that's right. That's the issue, always the issue.
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  Speaker 1: It would make jet lag all the more worse.
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  Speaker 2: Do you know, I think I'd put up with that
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  Speaker 2: rather than all those hours twenty hour flight.
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  Speaker 1: Yeah, I've got one of those coming up very soon.
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  Speaker 2: Thing you do.
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  Speaker 1: Yeah, but yeah, to watch this space story. But I
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  Speaker 1: just find it fascinating these kinds of leaps and technology.
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  Speaker 1: Let's move on a new theory about snowball Earth's fred
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  Speaker 1: I said, there's there's no Irish joke attached to this,
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  Speaker 1: and there's a good reason I said that.
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  Speaker 2: Which I'm probably going to slide step completely. It's about
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  Speaker 2: rocks in Scotland and in Australia.
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  Speaker 1: I thought it was. I thought they said there was
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  Speaker 1: some of these rocks in Ireland as well.
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  Speaker 2: Yeah, I think I think there are. I think that's
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  Speaker 2: I think.
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  Speaker 1: That's the loose connection I made.
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  Speaker 2: With it also includes rocks in Namibia and North America
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  Speaker 2: as well as Scotland. You're probably right Ireland in Ireland
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  Speaker 2: because it's the west of Scotland where these where these
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  Speaker 2: rocks are that have recently been analyzed, and I mean
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  Speaker 2: it's an interesting story. I've often wondered about snowball that
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  Speaker 2: I've never really looked at the details of it. So
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  Speaker 2: it's a period of about sixty million years ago, sorry,
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  Speaker 2: sixty million years long, but it was a long time ago.
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  Speaker 2: It began seven hundred million years ago, in fact, probably
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  Speaker 2: more like seven hundred and twenty million years ago, and
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  Speaker 2: lasted until about six hundred and thirty five million years ago.
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  Speaker 2: And it's called the Cryogenyan Cryogenian geological period. And anything
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  Speaker 2: with cryo in the front of it means it's frozen
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  Speaker 2: solid and so and so I thought, well, how do
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  Speaker 2: we know this? And the way we know it, and
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  Speaker 2: the way we know that glacial ice covered the whole
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  Speaker 2: planet is because you can see in the geology the
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  Speaker 2: effects of glaciation everywhere. It's not just you know, I
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  Speaker 2: grew up in a country where ten thousand years ago
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  Speaker 2: the whole of the northern part of Britain was under ice,
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  Speaker 2: and so by all my school lessons were about glacial
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  Speaker 2: features in the north of England, and so you could
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  Speaker 2: tell from rocks whether something has been glaciated, and that's
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  Speaker 2: how we know everywhere there is this layer of rock
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  Speaker 2: corresponding to looking back, you know, six seven hundred million
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  Speaker 2: years where you see the evidence of glaciation, and so
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  Speaker 2: the interpretation of that is that you had an ice
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  Speaker 2: age that was the put the grandfather of all ice ages.
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  Speaker 2: The whole planet was frozen. And so that the new
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  Speaker 2: research concerns evidence from rocks in Scotland. And what's remarkable
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  Speaker 2: is that the sort of glacier, the glacial evidence there
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  Speaker 2: shows up really clearly. For some reason, that has been
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  Speaker 2: preserved very well there, you know, underneath the sediments that
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  Speaker 2: were dropped on top of on top of it later on.
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  Speaker 2: But the bottom line about the reason why we got
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  Speaker 2: this ice age is a question. I'm not sure that
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  Speaker 2: in the article I sent you it goes into detail
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  Speaker 2: about it. But the thinking is that we were seeing
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  Speaker 2: a period or before this period, we were seeing a
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  Speaker 2: time when volcanic rocks were being eroded. They were being
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  Speaker 2: weathered very rapidly, and apparently these were particularly in Canada,
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  Speaker 2: these volcanic rocks, and looking back now perhaps seven hundred
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  Speaker 2: and twenty million years, they were eroded by weathering and
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  Speaker 2: that process sucks carbon dioxide out of the atmosphere, and
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  Speaker 2: so what you're seeing is a situation where the atmospheric
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  Speaker 2: carbon dioxide is lower than normal, and in fact it
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  Speaker 2: is probably it was probably about half what today's level is.
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  Speaker 2: Today's levels in the region of four hundred parts per
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  Speaker 2: million if carbon dioxide in the atmosphere, and that's enough
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  Speaker 2: to blanket our planet and keep the temperature stable unless
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  Speaker 2: you put more in, in which case the temperature goes up,
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  Speaker 2: as you know, but if you drop too far down,
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  Speaker 2: then you get an ice ball. They estimate the atmosphere
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  Speaker 2: carbon dioxide levels back in the cryogenic period or Cryogenonian period,
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  Speaker 2: they estimate they were below two hundred parts per million.
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  Speaker 2: And what that does is lets the heat just radiate
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  Speaker 2: out into the interspace and you lose heat. The Earth's
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  Speaker 2: surface becomes very cold, and basically you get the snowball Earth.
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  Speaker 2: You get an Earth that is covered with ice. It's
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  Speaker 2: the same sort of thing that we think happened on Mars.
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  Speaker 2: Mars is very low carbon dioxide content, and that's why
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  Speaker 2: we think it got cold and dry rather than as
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  Speaker 2: it once was.
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  Speaker 1: The other There's a lot of moving parts to this story,
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  Speaker 1: but one of the things I found most interesting was
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  Speaker 1: that if this mega freeze hadn't happened, life as we know,
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  Speaker 1: it may not have developed, it happened at this time.
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  Speaker 1: It was just microbial just that was it.
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  Speaker 2: That's that's correct. So and the thinking, yes, it was.
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  Speaker 2: It was single celled organisms until that time, and they
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  Speaker 2: were around for you know, three billion years or so.
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  Speaker 2: Nothing happened except these single celled organisms, principally cyanobacteria. They
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  Speaker 2: just did their thing and got on with life, but
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  Speaker 2: didn't evolve in any way. But the end, this end
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  Speaker 2: of the glacial period was such a sort of rapid
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  Speaker 2: climate change by the standards of the time, by geological standards,
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  Speaker 2: that the thinking is that you've got almost an arms
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  Speaker 2: race to adapt to this new situation where the microbes
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  Speaker 2: are not permanently in deep freeze. You've got a warming climate,
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  Speaker 2: and the evolution of the microbes kicks in at a
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  Speaker 2: much higher level than it was before. And that is
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  Speaker 2: where we think that the multi celled organism started to
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  Speaker 2: be formed. And that's what are the ancestors of all
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  Speaker 2: the animals that we see today.
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  Speaker 1: Yes, so basically those who survived the thaw or adapted
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  Speaker 1: to it created.
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  Speaker 2: Life as we know.
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  Speaker 1: It just an extraordinary sort of factor to come out
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  Speaker 1: of it. The other thing, I correct me if I'm wrong.
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  Speaker 1: But these rocks we were talking about in Ireland and
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  Speaker 1: Scotland and Australia and everywhere else. The reason that these
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  Speaker 1: are so different is I believe these were rocks that
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  Speaker 1: actually stuck out of the ice. Is that correct during.
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  Speaker 2: That yes period that they may have done or at
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  Speaker 2: least been subject to less placier activity. So yes, they
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  Speaker 2: may have you know, had only a thin layer of
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  Speaker 2: ice over them, rather than be under kilometers of ice.
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  Speaker 2: So I think you're right there. And just to confirm
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  Speaker 2: you quite right that some of these rocks are in
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  Speaker 2: Ireland as well. Hadn't spotted that Andrew in my reading
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  Speaker 2: of the paper. But yes, so you've got particularly you've
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  Speaker 2: got these rocks on some of the Scottish islands. These
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  Speaker 2: are small islands called the Gavelos and it's basically in
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  Speaker 2: the west of Scotland. It's under the Potaska Formation. This
• 14:53
  Speaker 2: is a geological area. Potaska very well known to Scott's
• 14:56
  Speaker 2: people because it's the name of a well known pipe tune.
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  Speaker 2: So let me quote from one of the authors of
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  Speaker 2: this work, and he's actually a PhD candidate at the
• 15:09
  Speaker 2: University University College London. The layers of rocks exposed on
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  Speaker 2: the Garvelis are globally unique. Underneath the rocks laid down
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  Speaker 2: during the unimaginable cold of the glaciation are seventy meters
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  Speaker 2: of older carbonate rocks formed in tropical waters. These layers
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  Speaker 2: record a tropical marine environment with flourishing cynobacterial life that
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  Speaker 2: gradually became cooler, marking the end of a billion years
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  Speaker 2: or so of a temperate climate on Earth. Most areas
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  Speaker 2: of the world are missing this remarkable transition because the
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  Speaker 2: ancient glaciers scraped and eroded the way the rocks underneath.
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  Speaker 2: But in Scotland, by some miracle, the transition can be seen,
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  Speaker 2: and I think that's underlining what you said. They were
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  Speaker 2: either sticking up through the ice or they weren't particularly
• 15:55
  Speaker 2: deeply covered by ice. So it's minerals and radiometric dating
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  Speaker 2: of the minerals that have allowed this discovery to be made.
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  Speaker 1: Yeah, it's incredible, isn't it. All The answers are right
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  Speaker 1: there in front of us in the dirt. Sometimes simple
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  Speaker 1: that that's how we we know so much about the
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  Speaker 1: history of not just our planet, but the you know,
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  Speaker 1: the other.
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  Speaker 2: Planets of the Solar System. Just learned from looking at
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  Speaker 2: the rocks.
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  Speaker 1: That's right, Yeah, fantastic. If you'd like to read the
• 16:26
  Speaker 1: article or chase up that story, it's on the Cosmos
• 16:30
  Speaker 1: magazine dot com website. There's a space Nut's Andrew Dunkley
• 16:34
  Speaker 1: here with Professor Brad Watson.
• 16:39
  Speaker 2: Murder your spacebuts.
• 16:42
  Speaker 1: Speaking of dirt, Fred, we've got the dirt on the
• 16:46
  Speaker 1: dinosaur asteroid. We we now know thanks to a new
• 16:51
  Speaker 1: study where it came from. This is fascinating too, it is.
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  Speaker 2: That's right, and you know, it's not that long ago
• 16:58
  Speaker 2: that people were really still speculating about where the remnants
• 17:02
  Speaker 2: of this asteroid was. We're now pretty certain that it's
• 17:07
  Speaker 2: in the Chickalog Basin in the Gulf of Mexico, that
• 17:11
  Speaker 2: that is the site which actually was the impact site
• 17:16
  Speaker 2: of this asteroid. So what you can do is you
• 17:20
  Speaker 2: can look at the rocks that you find in that region.
• 17:24
  Speaker 2: Once again, we're looking down at the dirt, but basically
• 17:29
  Speaker 2: look to see whether we know of anything like it
• 17:32
  Speaker 2: out there in the Solar system. And the bottom line
• 17:39
  Speaker 2: is that yes, we do find that. In particular, and
• 17:45
  Speaker 2: this is work being done at the University of Cologne
• 17:47
  Speaker 2: in Germany.
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  Speaker 1: The.
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  Speaker 2: Element Ruthenium is basically a chemical marker. Put it that way.
• 17:59
  Speaker 2: That is found in the debris around the Chick Salam
• 18:04
  Speaker 2: impact and apparently in other sediments around the world, because
• 18:08
  Speaker 2: the debris from that explosion spread all around the world.
• 18:11
  Speaker 2: It was so, you know, such a major piece of
• 18:16
  Speaker 2: piece of explosive material. It was only explosive because it
• 18:21
  Speaker 2: hit the ground at a very high speed, probably thirty
• 18:24
  Speaker 2: or forty kilometers per second. But the fingerprint of ruthenium
• 18:29
  Speaker 2: has been found in that debris, and it turns out
• 18:33
  Speaker 2: that that coincides with rocks in the Maine asteroid belt,
• 18:39
  Speaker 2: that's the region between Mars and Jupiter, but at the
• 18:43
  Speaker 2: outer edge, outer edge of the asteroid belt, not sort
• 18:48
  Speaker 2: of not the kind of place you'd expect. You would
• 18:51
  Speaker 2: think if that rock had come from the asteroid belt,
• 18:55
  Speaker 2: you'd think it will be near the inner edge, but
• 18:57
  Speaker 2: the chemical specifics tell you that it's actually at the
• 19:01
  Speaker 2: outer age. And that is really very very interesting deduction.
• 19:08
  Speaker 2: Who would have thought that we will built a pinpoint
• 19:11
  Speaker 2: where that asteroid came from sixty six million years after.
• 19:14
  Speaker 1: The event, and maybe the asteroid yeah, I guess they
• 19:20
  Speaker 1: worked it out on the chemical composition elements rather than backtracking.
• 19:24
  Speaker 2: Yes, that's right, it's we don't have enough information to backtrack.
• 19:28
  Speaker 2: We don't know what anglic came in at or you
• 19:31
  Speaker 2: know what it's all of it was before it collided
• 19:34
  Speaker 2: with Earth. So it's all about chemistry, is this? And
• 19:37
  Speaker 2: and in particular some quite quite sophisticate Well, I suppose
• 19:42
  Speaker 2: you call it chemical physics, because they're using radiation techniques
• 19:47
  Speaker 2: basically to look for these levels of ruthenium in the
• 19:53
  Speaker 2: basically in the debris from the from the asteroid creator
• 19:59
  Speaker 2: and surroundings, and basically, you know, looking at how it
• 20:07
  Speaker 2: compares with other asteroid impacts and carbonaceous meteorites which also
• 20:14
  Speaker 2: come from that region of the Solar System.
• 20:18
  Speaker 1: So what might have caused a rock from that particular
• 20:22
  Speaker 1: part of the Solar System to you know, turn its
• 20:25
  Speaker 1: attention to us. Did Satain get upset in check a
• 20:28
  Speaker 1: rock at us or something?
• 20:29
  Speaker 2: It's probably it's probably a just a gravitational disturbance, you know,
• 20:41
  Speaker 2: something that disturbed the orbit of this asteroid in its
• 20:47
  Speaker 2: comfortable zone of the asteroid belt. Maybe an interaction with
• 20:51
  Speaker 2: another asteroid, because when objects come together they needn't necessarily collide.
• 20:56
  Speaker 2: But if they can interact with each other gravitational so
• 21:00
  Speaker 2: that one of them gets thrown out of its orbits,
• 21:03
  Speaker 2: and you know, it's possible that that would have been
• 21:06
  Speaker 2: the case.
• 21:07
  Speaker 1: It's kind of like being in a crowd at a Chinese supermarket. Really,
• 21:10
  Speaker 1: That's that's what it's like.
• 21:13
  Speaker 2: Yes, yes, I didn't want to go that way, but
• 21:16
  Speaker 2: you ended up you have to you have to go
• 21:19
  Speaker 2: that way, Yeah, just because everything's so crowded. It's it's
• 21:22
  Speaker 2: a bit like that. The The thing is that that event,
• 21:28
  Speaker 2: whatever tipped it out of its comfortable orbits, that might
• 21:31
  Speaker 2: have happened a long time before the sixty six million
• 21:35
  Speaker 2: year day ago that we have for the for the
• 21:39
  Speaker 2: impact for the extinction of the dinosaurs. So it might
• 21:42
  Speaker 2: have been in a in an orbit that intersected the
• 21:45
  Speaker 2: Earth's orbit for a long long time before the crunch
• 21:49
  Speaker 2: finally came when it tried to be in the same
• 21:51
  Speaker 2: place at the same time as the Earth. So yes,
• 21:54
  Speaker 2: so we there's details for this story that we still
• 21:57
  Speaker 2: have a long way to finding out. But it may
• 22:01
  Speaker 2: well have been as I said, it's either a collision
• 22:03
  Speaker 2: with another asteroid or maybe even something like the gravitational
• 22:10
  Speaker 2: pull of gas giants. Maybe Jupiter perturbed that objects orbit
• 22:15
  Speaker 2: in such a way that it interacted with another asteroid
• 22:18
  Speaker 2: and got thrown out of turned out of the asteroid belt.
• 22:22
  Speaker 2: We probably will never know that. It's interesting enough, I think,
• 22:25
  Speaker 2: to discover whereabouts it came from.
• 22:28
  Speaker 1: Yes, the other thing that came out of this is
• 22:30
  Speaker 1: that it all bat writes off that this was a
• 22:34
  Speaker 1: comet impact. Yeah, but not absolutely.
• 22:39
  Speaker 2: Yeah, that's right. There's still there's still a possibility. But
• 22:43
  Speaker 2: you know, comets a different beast from asteroids. There, they've
• 22:47
  Speaker 2: contained lots of ice as well as the rock, and
• 22:50
  Speaker 2: that means that the chemistry of the residual material from
• 22:56
  Speaker 2: the impact would have different properties. So I think it's
• 23:01
  Speaker 2: you know, you can never say never, but the the
• 23:05
  Speaker 2: the body of opinion seems to be that it was
• 23:07
  Speaker 2: actually an astrolier rather than a comment. Yeah.
• 23:10
  Speaker 1: I do have just one more question about this story,
• 23:13
  Speaker 1: and this is the most important one for it most important.
• 23:16
  Speaker 1: You mentioned the element. So was the person who discovered
• 23:22
  Speaker 1: that named Ruth. That's a good question. I'd have to
• 23:27
  Speaker 1: take that one to notice. But my guess is that
• 23:30
  Speaker 1: that's where the name came from. Maybe maybe it was
• 23:35
  Speaker 1: somebody who was ruthless. They thought, yeah, I'll call it
• 23:39
  Speaker 1: ruthenium because I'm ruthless.
• 23:41
  Speaker 2: Who knows.
• 23:42
  Speaker 1: Yeah, that's that's a thought to that story. If you
• 23:46
  Speaker 1: would like to read it is available at space dot com.
• 23:51
  Speaker 1: This is Space Nuts Andrew Duncley here with Professor Fred Watson.
• 24:00
  Speaker 2: Space meds Now.
• 24:02
  Speaker 1: Fred to the so called crisis in cosmology. We're talking
• 24:06
  Speaker 1: about the the Hubble tension. Now we've we've done this
• 24:10
  Speaker 1: story a few times over the years. This is where
• 24:14
  Speaker 1: the basically the expansion speed of the universe, depending on
• 24:19
  Speaker 1: how how you calculate that number, comes up with two
• 24:23
  Speaker 1: different answers, and they've never been able to figure out why.
• 24:27
  Speaker 1: But now they're starting to think, well, there's no crisis
• 24:30
  Speaker 1: at all. Everything's right, Yes, So.
• 24:38
  Speaker 2: Let me just explain how this this tension, the Hubble
• 24:42
  Speaker 2: tension comes about. Yeah, because there are two ways of
• 24:47
  Speaker 2: measuring the expansion of the universe. One uses standard candles
• 24:55
  Speaker 2: and the other use is a standard ruler. And put
• 24:58
  Speaker 2: it that way, so the the standard candles. Taking that first,
• 25:02
  Speaker 2: if you know how bright your candle is, then you
• 25:05
  Speaker 2: can work out how far away it is from you,
• 25:07
  Speaker 2: because you know, you know it's real brightness. It's intrinsic brightness,
• 25:12
  Speaker 2: then you can work out what is going on in
• 25:16
  Speaker 2: terms of because we know the way light gets fainter.
• 25:20
  Speaker 2: We know the rule by which light gets fainter as
• 25:22
  Speaker 2: you move to greater in greater distances. It's what called
• 25:25
  Speaker 2: the inverse square, or it goes as the square of
• 25:28
  Speaker 2: the distance one over the square of the distance. So
• 25:31
  Speaker 2: standard candles are usually stars in galaxies, and in fact
• 25:38
  Speaker 2: this is what led us detect the expansion of the
• 25:42
  Speaker 2: universe in the first place, because in the early years
• 25:46
  Speaker 2: of the last century, around nineteen hundred, a group of
• 25:50
  Speaker 2: astronomers in the United States measured the intrinsic brightness of
• 25:55
  Speaker 2: a particular kind of variable style, one whose brightness varies,
• 25:58
  Speaker 2: but it varies in a in a periodic way. And
• 26:01
  Speaker 2: it turns out that there's a relationship between how frequently
• 26:05
  Speaker 2: it varies and what the intrinsic brightness is. And you
• 26:08
  Speaker 2: usually take it at peak brightness or minimum brightness, which
• 26:11
  Speaker 2: doesn't really matter as long as you know what it is.
• 26:14
  Speaker 2: And so that's the time honored way of working out
• 26:17
  Speaker 2: how far away galaxies are. To look for these variable
• 26:21
  Speaker 2: stars and then basically look at you know, how bright
• 26:27
  Speaker 2: they look to us and from that work out the distance,
• 26:31
  Speaker 2: and that lets you produce a value for what we
• 26:34
  Speaker 2: call the Hubble constant, which is the number that basically
• 26:38
  Speaker 2: tells you how fast the universe is expanding. The Hubble
• 26:43
  Speaker 2: constant is in units of kilometers per second per mega passe,
• 26:47
  Speaker 2: but we don't really need to worry about that because
• 26:49
  Speaker 2: at the moment, all we're interested in is the number.
• 26:52
  Speaker 2: And so until now, the best estimates from the standard candles,
• 26:57
  Speaker 2: in other words, the Cepheid variables have come out at
• 27:02
  Speaker 2: about seventy four kilometers per second megaparsec. But then the
• 27:07
  Speaker 2: standard ruler method is looking back at the flash of
• 27:10
  Speaker 2: the Big Bang, the cosmic microwave background radiation, which we
• 27:13
  Speaker 2: see as it was about thirteen billion years ago, and
• 27:18
  Speaker 2: there are features in that variation which have separations that
• 27:23
  Speaker 2: we know would be characteristic of a certain particular time.
• 27:28
  Speaker 2: And what we're talking about here when I say features,
• 27:30
  Speaker 2: I mean peaks and troughs in the temperature of the
• 27:33
  Speaker 2: Big Bang. Effectively what you're looking at, and from that
• 27:37
  Speaker 2: you can also deduce the Hubble constant the expansion rate
• 27:40
  Speaker 2: as it is today. But the answer you get from
• 27:44
  Speaker 2: that is sixty seven point five kilometers per second per
• 27:47
  Speaker 2: mega passe eg, which is round about six and a
• 27:51
  Speaker 2: half kilometers per second per mega part sect different from
• 27:54
  Speaker 2: the other one, and that is now we're in such
• 27:56
  Speaker 2: a precise era that that now has people worried. So
• 28:01
  Speaker 2: what's happened. Well, the same team who've done a huge
• 28:05
  Speaker 2: amount of this work in the past, led by Dr
• 28:08
  Speaker 2: Wendy Freeman Friedman, one of the big names in this
• 28:12
  Speaker 2: kind of science in the United States. Wendy and her
• 28:15
  Speaker 2: team have used our new toy web, the James Webspace Telescope, which.
• 28:23
  Speaker 1: We always knew it would it would solve this problem.
• 28:26
  Speaker 2: We knew it would certainly help. It would either make
• 28:29
  Speaker 2: it worse or it would solve it. And yeah, you're
• 28:31
  Speaker 2: right to cut to the chase. It's probably solved it
• 28:33
  Speaker 2: because it's now looking as though the method is more
• 28:40
  Speaker 2: like that, you know, the method where you measure the
• 28:41
  Speaker 2: brightness of these variable stars is giving an answer more
• 28:44
  Speaker 2: like seventy kilometers per second omega passe, which is much
• 28:48
  Speaker 2: closer to that sixty seven point five that you get
• 28:50
  Speaker 2: from the cosmic microwave background radiation. And it turns out
• 28:54
  Speaker 2: that when you think about the error potential eraror of
• 28:58
  Speaker 2: both of them. Then it overlaps. So in that regard,
• 29:01
  Speaker 2: you've got something that falls within the air bounds of
• 29:04
  Speaker 2: both of these methods, and so maybe we are seeing
• 29:07
  Speaker 2: the right answer at last.
• 29:08
  Speaker 1: So it basically brings it back to an average. That's right,
• 29:12
  Speaker 1: that's rights. Yes.
• 29:15
  Speaker 2: You know, when I started my career, Andrew, there were
• 29:19
  Speaker 2: two camps and basically they were using similar methods. One
• 29:25
  Speaker 2: said that the Hubble constant was fifty kilometers per second
• 29:29
  Speaker 2: per mega pass. The other said it was one hundred
• 29:31
  Speaker 2: kilometers per second per mega past second. They were both right.
• 29:35
  Speaker 2: I thought they were both right, and it turned out
• 29:37
  Speaker 2: that the answer, the real answer, was the average of
• 29:40
  Speaker 2: them with seventy or five of the.
• 29:43
  Speaker 1: There you go, pretty simple solution at the end of
• 29:46
  Speaker 1: the day, but a lot of hard work went when
• 29:49
  Speaker 1: in fine and yeah, we.
• 29:51
  Speaker 2: Hope that's that resolves the Hubble tension. It will be
• 29:53
  Speaker 2: gratefully cosmic class disappeared. Yeah, yeah, I wouldn't be surprised though.
• 29:58
  Speaker 2: In months to camps somebody comes up with a debunking theory.
• 30:03
  Speaker 1: Well, there you go, it couldn't happen. It could happen
• 30:07
  Speaker 1: at this point in time, looks like it might have
• 30:10
  Speaker 1: been resolved. This has been frustrating for a long time,
• 30:13
  Speaker 1: but maybe as simple as hang on a sec. You're
• 30:16
  Speaker 1: both right, and here's why. Yeah, that's stories on SYE
• 30:21
  Speaker 1: Tech Daily dot com. Question without Notice spread that's come
• 30:25
  Speaker 1: through from one of our live viewers, Wayne high wayIn
• 30:30
  Speaker 1: this harks back to the snowball Earth story we did. Wayne,
• 30:35
  Speaker 1: I wonder how much bigger the diameter of a frozen
• 30:38
  Speaker 1: Earth would be to the current Earth. Do we have
• 30:41
  Speaker 1: any idea what that might have been.
• 30:43
  Speaker 2: Yeah, it probably wasn't that much different. It's you know,
• 30:49
  Speaker 2: I mean at the moment, a lot of that water
• 30:52
  Speaker 2: is still there, but it's wet. You know, this is
• 30:56
  Speaker 2: now it's turned into eyes, so it's not going to
• 30:59
  Speaker 2: be it's certainly not going to be tens of killer
• 31:03
  Speaker 2: meters different. It might be a few killo meters different
• 31:08
  Speaker 2: on average, and I'm talking about the average. But I
• 31:11
  Speaker 2: don't think it would you know, it wouldn't have turned
• 31:13
  Speaker 2: into a gas giant or anything like that. It's an
• 31:16
  Speaker 2: interesting question though, because we think it's because of frozen
• 31:18
  Speaker 2: water out in the depths of the Solar System adding
• 31:22
  Speaker 2: to the mass of the gas giants. As they were
• 31:25
  Speaker 2: being formed. We think that is one reason why they
• 31:27
  Speaker 2: became so big, because they had enough bounds to hold
• 31:30
  Speaker 2: on to a gas envelope. And so it's a good
• 31:34
  Speaker 2: question to ask that at what difference would the ice blake.
• 31:38
  Speaker 2: But this is really just a surface layer of ice
• 31:41
  Speaker 2: rather than a solid block of ice, which may be
• 31:43
  Speaker 2: at the core of the gas giants.
• 31:46
  Speaker 1: Indeed, all right, thank you. Why nice to get questions
• 31:49
  Speaker 1: without notice while we're going out live during our recording sessions.
• 31:53
  Speaker 1: Good to hear from you, Fred. We're just about Dan.
• 31:55
  Speaker 1: Thank you very much.
• 31:57
  Speaker 2: A pleasure, Andrew, good to talk and some interesting topics,
• 32:01
  Speaker 2: and there'll be more next week.
• 32:03
  Speaker 1: Indeed there will, Thanks Red Professor Fred Watson, Astronomer at Large.
• 32:07
  Speaker 1: I don't forget to check us out online Spacenuts podcast
• 32:10
  Speaker 1: dot com, space Nuts dot io. We can check out
• 32:13
  Speaker 1: the shop, maybe become a supporter of the podcast if
• 32:16
  Speaker 1: you're interested, just have a bit of a flick around.
• 32:19
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• 32:22
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• 32:24
  Speaker 1: or click the subscribe button depending on which platform it is.
• 32:29
  Speaker 1: And thanks to Hu in the studio as always and
• 32:32
  Speaker 1: from me Andrew Unkley. We will see you again soon
• 32:35
  Speaker 1: on the very next episode of Space Nuts. Bye bye,
• 32:39
  Speaker 1: Space Nuts. You'll be listening to the Space Nuts podcast
• 32:44
  Speaker 1: available at Apple Podcasts, Spotify, iHeartRadio, or your favorite podcast player.
• 32:50
  Speaker 1: You can also stream on demand at guides dot com.
• 32:54
  Speaker 2: This has been another quality podcast production from nights dot com.