Latest / Space News Today / Snowball Earth, Dinosaur Asteroids & the Hubble Tension Unravelled | Space Nuts: Astronomy...

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Snowball Earth, Dinosaur Asteroids & the Hubble Tension Unravelled | Space Nuts: Astronomy... · Space News Today

• 0:00
  Space Nuts is taking a bit of a break at
• 0:02
  the moment. Uh Fred and I will be back
• 0:04
  uh in the not too distant future with
• 0:06
  fresh episodes. In the meantime, enjoy
• 0:08
  some of uh the key episodes that we have
• 0:11
  presented over the years, major events
• 0:14
  in astronomy and space science and we'll
• 0:17
  see you real soon.
• 0:19
  >> Space Nuts.
• 0:20
  >> Hi there. Thanks for joining us on
• 0:22
  another episode of Space Nuts. Andrew
• 0:24
  Dunley here and it's good to have your
• 0:26
  company. Coming up on this episode,
• 0:29
  we're going to be looking at Snowball
• 0:31
  Earth. There was a time where it was
• 0:33
  just a frozen sphere of nothingness for
• 0:37
  well, billions of years. Uh, now they
• 0:39
  have a new theory about that and it's no
• 0:41
  Irish joke.
• 0:43
  There's a clue in there. Uh, the
• 0:46
  dinosaur asteroids origin has been
• 0:48
  revealed. Yep. The thing that started
• 0:50
  the
• 0:52
  getting rid of them all across the
• 0:54
  planet. We know where it came from. and
• 0:57
  uh the so-called crisis in cosmology
• 0:59
  might not be a crisis at all. We're
• 1:01
  talking about the Hubble tension. We'll
• 1:03
  talk about all of that on this episode
• 1:05
  of Space Nuts.
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  >> 15 seconds. Guidance is internal. 10 9
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  Ignition sequence start.
• 1:14
  >> Space Nuts.
• 1:15
  >> 5 4 3 2 1 2 3 4 5 5 4 3 2 1
• 1:20
  >> Space Nuts.
• 1:21
  >> Astronauts report. It feels good. And to
• 1:24
  help us uh unravel all of that, decipher
• 1:27
  it, and uh use his code book to figure a
• 1:30
  few more things out is Professor Fred
• 1:32
  Watson, an astronomer at large. Hello,
• 1:34
  Fred.
• 1:34
  >> Hello, Andrew. Keep up the good work
• 1:36
  there. It's going very well.
• 1:40
  >> Uh good to see you. Now I I just I
• 1:42
  thought I'd sort of start out of left
• 1:44
  field because um I I spotted a story uh
• 1:48
  only today actually uh which doveetales
• 1:52
  with something we talked about some time
• 1:53
  ago and and that was the work that's
• 1:55
  being done to perfect uh engine
• 1:59
  technology to achieve greater speeds
• 2:02
  >> uh for interstellar travel in years to
• 2:05
  come or maybe not interstellar but
• 2:07
  interplanetary perhaps. And we know NASA
• 2:09
  is is working on this kind of technology
• 2:12
  to to create uh really
• 2:16
  fast and high performance engines.
• 2:19
  They're working with I think it's
• 2:20
  General Electric to achieve that. Uh
• 2:23
  they may have been gazumped. Fred, have
• 2:25
  you heard about this? Uh no.
• 2:29
  Uh the Chinese the Chinese claim to have
• 2:32
  developed a a new engine that can
• 2:36
  achieve a speed of 12,000
• 2:39
  mph or 19,700 km an hour and uh the
• 2:44
  aircraft can reach an altitude of 30
• 2:47
  kilome. Now you compare that to the
• 2:49
  Concord uh it's uh Mac 16 versus Mac 2
• 2:55
  uh which is an extraordinary claim. Now,
• 2:58
  apparently they've released a paper
• 2:59
  which has been peer reviewed from what I
• 3:02
  understand. Um, and it's not April the
• 3:05
  1st. I'm confident of that. So, they
• 3:08
  reckon that they've they've made this
• 3:10
  leap in technology to develop a Max 16
• 3:15
  engine. And just think of this, Fred,
• 3:17
  you'd be able to fly from Sydney to New
• 3:20
  York in 50 minutes.
• 3:23
  >> Yes, that's what
• 3:24
  >> 50 minutes. Uh, That's extraordinary if
• 3:28
  it if it's real. And I I don't see why
• 3:31
  it wouldn't be, but you never know with
• 3:32
  these things. But um apparently uh
• 3:35
  according to the paper, the engine
• 3:37
  operates in two modes. There's a
• 3:38
  continuous rotating detonation engine,
• 3:40
  which is a scary thing in itself by the
• 3:42
  sound of it, which will get it to mark
• 3:43
  7. And uh you know, the air and the fuel
• 3:47
  create a rotating shock wave with
• 3:49
  continuous thrust. and then a straight
• 3:52
  line oblique detonation engine which
• 3:55
  fires above Mark 7 and pushes it all the
• 3:58
  way to Mark 16. Um, it sounds amazing.
• 4:02
  Sounds amazing. Uh, how far short they
• 4:06
  are of getting this into production, I
• 4:08
  don't know, but um, it certainly sounds
• 4:10
  like it's in development. That would be
• 4:12
  amazing to to be able to achieve those
• 4:15
  kinds of speeds. Uh, it would
• 4:17
  revolutionize travel around the world.
• 4:20
  But it's been done already
• 4:23
  by
• 4:24
  >> Yeah. The British have been working on
• 4:26
  this for decades now with their air.
• 4:31
  It's an air breathing um it's a hybrid
• 4:34
  engine that breathes air at at at low
• 4:38
  altitudes and turns into a rocket motor
• 4:40
  when you get above the Earth's
• 4:41
  atmosphere.
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  >> Yeah, I think I did hear about that. I
• 4:44
  didn't know it got to those sorts of
• 4:45
  speeds.
• 4:46
  >> Yeah. Well, it can it's capable of
• 4:47
  entering orbit. So, it can get up to,
• 4:49
  you know, 26,000 kilometers an hour, but
• 4:52
  but but it's then acting as a rocket
• 4:54
  motor. So, it's um the project was
• 4:56
  called well hotel was the style of thing
• 5:00
  horizontal takeoff and landing. Um, so
• 5:03
  it's flies like a plane, takes off like
• 5:05
  a plane with the air burning jet
• 5:07
  engines, just gradually accelerates, uh,
• 5:11
  clicks over into being a, um, a rocket
• 5:15
  motor, uh, when the atmosphere gets too
• 5:17
  rarified and then sends you up to orbit.
• 5:20
  Uh, but the, as I remember right, I
• 5:22
  think it's called the Saber, the engine,
• 5:24
  if I remember right, it's Saber. But the
• 5:26
  big problem was, um, keeping the air
• 5:31
  cool.
• 5:32
  And there was some the main breakthrough
• 5:34
  was apparently a heat exchanger that
• 5:37
  could bring the temperature of the air
• 5:39
  uh down from 700° C or something to
• 5:44
  liquid nitrogen temperatures in
• 5:46
  something like a thousandth of a second
• 5:47
  as it passes through the engine.
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  >> Um and and that was a big breakthrough.
• 5:51
  Now we've I think we've spoken about it
• 5:53
  before a long long time ago because
• 5:54
  there hasn't really been much news. It
• 5:56
  was being supported by the British
• 5:58
  government. I don't know whether that
• 5:59
  support has has now dwindled um because
• 6:03
  it would be you know the idea about this
• 6:05
  was economics. It was to be able to have
• 6:07
  the same spa spacecraft that will take
• 6:08
  you up there and bring you back and was
• 6:10
  completely reusable and to some extent I
• 6:13
  think um uh Elon Musk SpaceX and their
• 6:16
  Falcon 9 have kind of cornered the
• 6:18
  market on the because they've they've
• 6:20
  now got reusable spacecraft which are
• 6:22
  routinely being used every day uh
• 6:25
  almost. So maybe there's no space for
• 6:27
  it, but yeah, extraordinary technology
• 6:29
  and and I'm sure the Chinese technology
• 6:32
  is is above board what you've just been
• 6:34
  describing.
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  >> Yeah, it's from the Beijing Power
• 6:36
  Machinery Institute and they've
• 6:38
  published their paper in the Chinese
• 6:40
  Journal of Propulsion Technology. I can
• 6:42
  I can see a problem with it though.
• 6:44
  Let's say they do create an airliner
• 6:46
  that can do that trip in 50 minutes from
• 6:49
  New York to Sydney, for example. You'd
• 6:51
  leave at 7:00 in the morning in New
• 6:52
  York. You'd arrive at 11:00 p.m. 50
• 6:55
  minutes later in Sydney. So you'd get up
• 6:59
  and get on the plane and then get to
• 7:01
  Sydney and then have to go to bed wide
• 7:02
  awake.
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  >> Yes,
• 7:05
  >> that's right. That's the issue is it
• 7:08
  would make jet lag all the more worse.
• 7:10
  >> Yeah. You know, I think I'd put up with
• 7:13
  that rather than have all those
• 7:15
  >> 20 hours.
• 7:16
  >> Yeah. 20our flight. Yeah. I've got one
• 7:19
  of those coming up very soon actually.
• 7:21
  >> You do? That's right. Yeah. Yeah.
• 7:22
  >> Yeah. It'll be Yeah. It's a watch this
• 7:24
  space story, but I just find it
• 7:26
  fascinating these these kinds of um
• 7:28
  leaps in technology.
• 7:30
  >> Let's move on. Uh a new theory about
• 7:32
  snowball earth. Fred, I said there's um
• 7:36
  there's no Irish joke attached to this,
• 7:37
  and there's a good reason I said that,
• 7:41
  >> which I'm probably going to sidestep
• 7:42
  completely. Uh it's about rocks in
• 7:45
  Scotland and in Australia.
• 7:48
  >> I thought it was I thought they said
• 7:49
  there was some of these rocks in Ireland
• 7:50
  as well. Yeah, I think I think there are
• 7:52
  I think that's right. I think that's the
• 7:55
  loose connection I made with it.
• 7:58
  >> Um it it also includes rocks in Namibia
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  uh and North America uh as well as uh
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  Scotland. Uh you're probably right,
• 8:07
  Ireland in Ireland because um it's the
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  west of Scotland where these where these
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  rocks are that have recently been
• 8:13
  analyzed. Uh and the I mean it's an
• 8:17
  interesting story. I've often wondered
• 8:18
  about Snowball Earth. never really
• 8:20
  looked at at the details of it. So, it's
• 8:23
  a period of about 60 million years ago.
• 8:27
  Oh, sorry, 60 million years long, but it
• 8:30
  was a long time ago. It began 700
• 8:33
  million years ago. Uh, in fact, probably
• 8:36
  more like 720 million years ago and
• 8:39
  lasted until about 635 million years
• 8:41
  ago. And it's called the Cryogenian
• 8:44
  Cryogenian geological period. And
• 8:46
  anything with cryo in the front of it
• 8:48
  means it's frozen solid.
• 8:50
  >> Yeah.
• 8:51
  >> And so um and so I thought well how do
• 8:54
  we know this? And the way we know it
• 8:58
  and the way we know that glacial ice
• 9:02
  covered the whole planet is because you
• 9:05
  can see in the geology the effects of
• 9:08
  glaciation
• 9:10
  uh everywhere. It's not just, you know,
• 9:13
  I I grew up in a country where 10,000
• 9:15
  years ago, the whole of the northern
• 9:17
  part of Britain was under ice. And so my
• 9:20
  all my school lessons were about glacial
• 9:22
  features uh in the north of England. And
• 9:25
  so so you could tell from rocks uh
• 9:29
  whether something has been glaciated.
• 9:32
  And that's how we know everywhere there
• 9:34
  is this layer of rock uh corresponding
• 9:37
  to looking back you know six 6 700
• 9:40
  million years where you see the evidence
• 9:42
  of glaciation. Um and so the
• 9:45
  interpretation of that is that you uh
• 9:48
  you had an ice age that was the put it
• 9:51
  the the grandfather of all ice ages. Uh
• 9:54
  the whole planet was frozen. Uh and so
• 9:58
  the the new research concerns uh
• 10:00
  evidence from rocks in Scotland. Uh and
• 10:03
  what's remarkable is that uh the sort of
• 10:08
  glacia the glacial evidence there shows
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  up really clearly. Uh for some reason
• 10:13
  that has been preserved very well uh
• 10:16
  there, you know, underneath the
• 10:18
  sediments that were dropped on top of on
• 10:20
  top of it um later on. But um the bottom
• 10:24
  line about the uh the reason why we got
• 10:28
  this ice age is a is a question um I'm
• 10:32
  not sure that the article I sent you it
• 10:35
  goes into detail about it. Uh but the
• 10:37
  thinking is that we were seeing a period
• 10:41
  when um or before this period uh we were
• 10:45
  seeing a time when uh volcanic rocks
• 10:51
  were being were being uh eroded. They
• 10:54
  were being weathered very rapidly. And
• 10:56
  apparently these were particularly in
• 10:58
  Canada uh these volcanic rocks. I'm
• 11:01
  looking back now perhaps 720 million
• 11:04
  years. um they were eroded by weathering
• 11:08
  and that process sucks carbon dioxide
• 11:11
  out of the atmosphere. Uh and so um what
• 11:14
  you're seeing is a situation where the
• 11:18
  atmospheric carbon dioxide is lower uh
• 11:22
  than normal and in fact uh it is
• 11:25
  probably was probably about half uh what
• 11:28
  today's level is. today's levels in the
• 11:31
  region of 400 parts per million of
• 11:33
  carbon dioxide in the atmosphere. And
• 11:35
  that's enough to blanket our planet and
• 11:37
  keep the temperature stable. Uh unless
• 11:39
  you put more in in which case the
• 11:41
  temperature goes up as you know. Uh but
• 11:43
  uh if you drop too far down uh then you
• 11:46
  get an ice ball. Um they estimate the
• 11:50
  atmospheric carbon dioxide levels uh
• 11:54
  back in the cryogenic period or
• 11:56
  cryogenonian period. uh they estimate
• 11:59
  they were below 200 parts per million.
• 12:02
  And what that does is lets the heat just
• 12:04
  radiate out into the uh into space and
• 12:07
  you lose heat. The earth's surface
• 12:09
  becomes very cold. Uh and uh and
• 12:12
  basically you get the snowball earth.
• 12:13
  You get an earth that is covered with
• 12:15
  ice. Um the it's the same sort of thing
• 12:18
  that we think happened on Mars. Mars is
• 12:20
  very low carbon dioxide content and
• 12:22
  that's why we think it got cold and dry
• 12:24
  rather than warm and white as it once
• 12:26
  was. M
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  >> the other there's a lot of moving parts
• 12:29
  to this story but uh one of the things I
• 12:32
  found most interesting was if this mega
• 12:37
  freeze hadn't happened life as we know
• 12:40
  it may not have developed
• 12:42
  >> because up until this time it was just
• 12:44
  microbial just that was it.
• 12:47
  >> That's that's correct. Um so uh and the
• 12:50
  thinking yes it was it was
• 12:52
  single-sellled organisms until that time
• 12:54
  and they they were around for you know
• 12:56
  three billion years or so um that
• 12:59
  nothing happened except these single
• 13:01
  cellled organisms uh principally
• 13:03
  cyanobacteria they just did their thing
• 13:05
  and got on with life but didn't evolve
• 13:08
  in any way. Uh but the end this this end
• 13:12
  of the glacial period was such a sort of
• 13:17
  rapid climate change by the standards of
• 13:20
  the of the time by geological standards
• 13:23
  that the thinking is that you've got to
• 13:25
  uh almost an arms race uh to adapt um to
• 13:30
  to to this new situation where the
• 13:34
  microbes are not permanently in deep
• 13:36
  freeze. you've got a warming climate and
• 13:39
  the and the evolution of the microbes
• 13:41
  kicks in at a much higher level than it
• 13:44
  was before and that is where uh we think
• 13:47
  that the multi-elled organism started to
• 13:49
  be formed and that's what are the
• 13:52
  ancestors of all the animals that we see
• 13:54
  today. Yeah. So basically those who
• 13:56
  survived the thor or adapted to it uh
• 14:00
  created life as we know it. Yeah. just
• 14:02
  this extraordinary um sort of factor to
• 14:06
  come out of it. The other thing I and I
• 14:10
  correct me if I'm wrong, but these rocks
• 14:12
  we were talking about in Ireland and
• 14:13
  Scotland and Australia and everywhere
• 14:15
  else uh the reason that these are so
• 14:19
  different is I believe these were rocks
• 14:21
  that actually stuck out of the ice. Is
• 14:24
  that correct?
• 14:27
  >> During that period,
• 14:29
  >> they may have done or or at least been
• 14:32
  subject to less glacial activity. So,
• 14:34
  yes, they they they may have, you know,
• 14:37
  had only a thin layer of ice over them
• 14:39
  rather than be under kilometers of ice.
• 14:42
  Um, so I think you're right there. And
• 14:44
  and and just to to confirm, you're quite
• 14:47
  right that some of these rocks are in
• 14:48
  Ireland as well. Uh I hadn't spotted
• 14:51
  that, Andrew, in my reading of the
• 14:53
  paper. Uh but yes, so you've got um uh
• 14:58
  particularly you've got uh these rocks
• 15:01
  on some of the Scottish islands. These
• 15:04
  are small islands called the Gavllas. Uh
• 15:06
  and it's um basically in the west of
• 15:09
  Scotland. Uh it's under the Portas
• 15:13
  formation. This is a geological area.
• 15:15
  Potas very well known to Scots people
• 15:17
  because it's a name of a well-known pipe
• 15:19
  tune. Um so let me quote from one of the
• 15:22
  authors of this work um and he's he's
• 15:25
  actually a PhD uh candidate at the UN uh
• 15:30
  University College London. The layers of
• 15:33
  rocks exposed on the Garvellis are
• 15:35
  globally unique. Underneath the rocks
• 15:37
  laid down during the unimaginable cold
• 15:40
  of the glaciation are 70 m of older
• 15:43
  carbonate rocks formed in tropical
• 15:45
  waters. These layers record a tropical
• 15:48
  marine environment with flourishing
• 15:50
  cyanobacterial life that gradually
• 15:52
  became cooler, marking the end of a
• 15:54
  billion years or so of a temperate
• 15:56
  climate on Earth. Um, most areas of the
• 15:59
  world are missing this remarkable
• 16:01
  transition because the ancient glacias
• 16:04
  scraped and eroded the way the rocks
• 16:06
  underneath. But in Scotland, by some
• 16:08
  miracle, the transition can be seen. And
• 16:10
  I think that's underlining what you
• 16:12
  said. They were either sticking up
• 16:13
  through the ice or they weren't
• 16:14
  particularly deeply covered by ice. So,
• 16:18
  it's minerals and uh radiometric dating
• 16:20
  of the minerals that have allowed this
• 16:23
  discovery to to to be made.
• 16:26
  >> Yeah. It's incredible, isn't it? All the
• 16:28
  answers are right there in front of us
• 16:30
  in the dirt sometimes.
• 16:31
  >> Simple as that.
• 16:33
  >> That's how we it's we know so much about
• 16:36
  the history of not just our planet, but
• 16:38
  the you know, the other planets of the
• 16:40
  solar system. just learned from looking
• 16:42
  at the rocks. That's right.
• 16:44
  >> Yeah. Fantastic. Uh if you'd like to
• 16:46
  read the article or chase up that story,
• 16:49
  it's uh on the cosmosine.com
• 16:52
  website. This is Space Nuts. Andrew
• 16:55
  Dunley here with Professor Brad Watson.
• 16:58
  Let's take a break from the show to tell
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  or you can tap on the link in the show
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  notes.
• 18:41
  >> You're clear also.
• 18:43
  >> Space nuts.
• 18:44
  >> Uh speaking of dirt, Fred, uh we've got
• 18:47
  we've got the dirt on the dinosaur
• 18:49
  asteroid. We uh uh we now know thanks to
• 18:52
  a new study where it came from. This is
• 18:55
  fascinating, too.
• 18:57
  >> It it is. That's right. Uh and you know,
• 18:59
  it's not that long ago that people were
• 19:01
  really still speculating about where the
• 19:04
  remnants of this asteroid was. Uh we're
• 19:07
  now pretty certain that it's in the
• 19:09
  Chicelog Basin
• 19:12
  in the Gulf of Mexico. that that is the
• 19:15
  uh the site which uh actually was the
• 19:18
  impact site of this asteroid. So what
• 19:20
  you can do is you can look at the the
• 19:23
  rocks um that you find in that region.
• 19:26
  Once again, we're looking down at the
• 19:28
  dirt and um but basically look to see
• 19:32
  whether we know of anything like it out
• 19:35
  there in the solar system. Um and the
• 19:40
  bottom line is that yes we do find that
• 19:45
  uh in in particular and this is work
• 19:48
  being done at the University of Cologne
• 19:49
  in Germany um the uh the element
• 19:54
  ruthenium
• 19:56
  um is basically a chemical marker if I
• 20:00
  can put it that way that is found in the
• 20:04
  debris around the chicks impactor And
• 20:07
  apparently in other sediments around the
• 20:09
  world because the debris from that
• 20:11
  explosion spread all around the world.
• 20:13
  It was so, you know, such a uh such a a
• 20:16
  major uh piece of uh piece of of
• 20:20
  explosive material. It it was only
• 20:22
  explosive because it hit the ground at a
• 20:24
  very high speed, probably 30 or 40
• 20:27
  kilometers/s. Um but the the fingerprint
• 20:30
  of ruthenium has been found in that
• 20:32
  debris. And it turns out that that
• 20:36
  coincides with rocks in the the main
• 20:40
  asteroid belt. That's the region between
• 20:43
  Mars and Jupiter, but at the outer edge
• 20:47
  uh outer edge of the main asteroid belt.
• 20:50
  Not sort of not the kind of place you'd
• 20:52
  expect. You would think if the if that
• 20:55
  rock had come from uh the asteroid belt,
• 20:57
  you'd think it would be the near the
• 20:58
  inner edge, but the chemical um
• 21:01
  specifics tell you that it's actually at
• 21:03
  the outer edge. Uh and um that is really
• 21:07
  very very interesting deduction. Uh who
• 21:11
  would have thought that we we would be
• 21:12
  able to pinpoint where that asteroid
• 21:14
  came from uh 66 million years after the
• 21:17
  event. Uh and um
• 21:19
  >> maybe the asteroid I
• 21:21
  >> Yeah, I guess they worked it out on the
• 21:22
  chemical composition elements rather
• 21:25
  than backtracking.
• 21:27
  >> Yes, that's right. Um it's it we don't
• 21:29
  have enough information to backtrack. We
• 21:31
  don't know what angle it came in at or
• 21:33
  you know what its orbit was before it
• 21:35
  collided with Earth. So it's it's all
• 21:37
  about chemistry is this and um and in
• 21:40
  particular some quite uh quite
• 21:43
  sophisticated well I suppose you call it
• 21:44
  chemical physics because they're using
• 21:47
  radiation techniques uh basically to to
• 21:51
  to look for these levels of runium uh in
• 21:54
  in the basically in the debris from the
• 21:57
  uh from the um uh asteroid uh crater and
• 22:01
  and surroundings. uh and um basically uh
• 22:06
  you know looking at uh how it compares
• 22:09
  with other um asteroid impacts and
• 22:13
  carbonatous meteorites which also come
• 22:16
  from that region of the of the solar
• 22:18
  system.
• 22:20
  >> So what might have caused a rock from
• 22:23
  that particular part of the solar system
• 22:26
  to you know turn its attention to us?
• 22:28
  Did Saturn get upset and chuck a rock at
• 22:30
  us or something? is
• 22:33
  um it's probably uh it's it's probably
• 22:37
  um a a just a gravitational disturbance,
• 22:42
  you know, something that disturbed the
• 22:47
  uh orbit of this asteroid in its
• 22:49
  comfortable zone of the asteroid belt.
• 22:52
  Maybe an interaction with another
• 22:54
  asteroid because when objects come
• 22:56
  together, they needn't necessarily
• 22:58
  collide. But if they can interact with
• 23:01
  each other gravitationally so that one
• 23:02
  of them gets thrown out of of of its
• 23:05
  orbits and you know it's possible that
• 23:07
  that would have been the case. U it's
• 23:09
  kind of like being in a crowd at a
• 23:11
  Chinese supermarket. Really? That's
• 23:14
  >> that's what it's like.
• 23:15
  >> Yes. Yes.
• 23:16
  >> You didn't want to go that way but you
• 23:18
  you ended up going
• 23:20
  >> you have to you have to go that way.
• 23:21
  Yeah. Just because everything's so
• 23:23
  crowded. It's it's it's a bit like that.
• 23:25
  The um um the thing is that that event
• 23:30
  whatever tipped it out of its
• 23:31
  comfortable orbit that might have
• 23:34
  happened a long time before the 66
• 23:36
  million year date a ago uh that we for
• 23:41
  the uh for the impact for the extinction
• 23:43
  of the dinosaurs. So it might have been
• 23:45
  in a in an orbit that intersected the
• 23:47
  earth's orbit for a long long time uh
• 23:50
  before the crunch finally came when it
• 23:52
  tried to be in the same place at the
• 23:53
  same time as the earth. Uh so yes, so so
• 23:56
  we there's details for this story that
• 23:58
  we still have a long way to finding out.
• 24:02
  Um but it may well have been, as I said,
• 24:04
  it's either a collision with another uh
• 24:07
  asteroid or maybe even something like
• 24:11
  the gravitational pull of gas giants.
• 24:13
  Maybe Jupiter uh perturbed that object's
• 24:17
  orbit in such a way that it interacted
• 24:19
  with another asteroid and got got thrown
• 24:21
  out of uh thrown out of the asteroid
• 24:24
  belt. We probably will never know that.
• 24:26
  Uh it's interesting enough, I think, to
• 24:27
  to discover whereabouts it came from.
• 24:30
  >> Yes. The other thing that uh came out of
• 24:32
  this is that it all but writes off that
• 24:36
  this was a comet impact.
• 24:38
  >> Yes.
• 24:38
  >> Um but not absolutely.
• 24:41
  >> Yeah, that's right. There's still uh
• 24:43
  there's still a possibility, but you
• 24:45
  know, comets are a different beast from
• 24:48
  from asteroids. They contain lots of ice
• 24:51
  uh as well as the rock. And that means
• 24:53
  that the chemistry of the the residual
• 24:57
  material from the impact would have
• 24:59
  different properties. Uh so I think um
• 25:02
  it's uh you know you can never say never
• 25:05
  but the the the body of opinion seems to
• 25:09
  be that it was actually an asteroid
• 25:10
  rather than a comet.
• 25:11
  >> Yeah.
• 25:12
  >> I do have just one more question about
• 25:14
  this story and this is the most
• 25:16
  important one for it. most important.
• 25:19
  You mentioned the element recinium.
• 25:22
  >> Yes.
• 25:22
  >> So, was the person who discovered that
• 25:24
  named Ruth?
• 25:28
  >> Um, that's a good question. I'd have to
• 25:30
  take that one on notice, but my guess is
• 25:31
  that that's where the name came from or
• 25:35
  maybe maybe it was somebody who was
• 25:38
  ruthless.
• 25:39
  >> And they thought, "Yeah, I'll call it
• 25:41
  Runthenian because I'm ruthless." Who
• 25:43
  knows that?
• 25:44
  >> Yeah. Yeah, that's that's a thought,
• 25:46
  too. Uh that story if you would like to
• 25:49
  read it is available at space.com.
• 25:54
  >> This is Space Nuts. Andrew Dunley here
• 25:55
  with Professor Fred Watson
• 26:01
  and I feel
• 26:02
  >> space nuts.
• 26:03
  >> Uh now Fred to the so-called crisis in
• 26:07
  cosmology. We're talking about uh the
• 26:09
  the Hubble tension. Now we've we've done
• 26:12
  this story a few times over the years.
• 26:14
  This this is where the basically the
• 26:18
  expansion speed of the universe um
• 26:21
  depending on how how you calculate
• 26:24
  uh that number comes up with two
• 26:25
  different answers and they have never
• 26:27
  been able to figure out why. But now
• 26:30
  they're starting to think well there's
• 26:32
  no crisis at all. Everything's right. Um
• 26:36
  yes. So
• 26:39
  um the let me just explain how the this
• 26:43
  this tension the Hubble tension comes
• 26:45
  about.
• 26:46
  >> Yeah.
• 26:46
  >> Uh because there are there are two ways
• 26:48
  of of measuring uh the expansion of the
• 26:52
  universe. Uh one uses standard candles
• 26:57
  and the other uses a standard ruler.
• 27:00
  >> Um put it that way. So the standard
• 27:02
  candle's taking that first. Um if you
• 27:05
  know how bright your candle is, then you
• 27:07
  can work out how far away it is from
• 27:09
  you. Uh because you you you know you
• 27:12
  know it's real brightness, it's
• 27:13
  intrinsic brightness, then you can work
• 27:15
  out what is going on uh in terms of
• 27:19
  because we know the way light gets
• 27:21
  fainter. We know the rule by which light
• 27:24
  gets fainter as you move to greater and
• 27:25
  greater distances. It's what called the
• 27:27
  inverse square law. Um it it goes as the
• 27:30
  square of the distance or one over the
• 27:31
  square of the distance. So uh standard
• 27:34
  candles are usually stars in galaxies.
• 27:40
  Uh and in fact this is what uh let us
• 27:43
  detect the expansion of the universe in
• 27:46
  the first place because u in the early
• 27:48
  years of the last century around 1900 um
• 27:52
  a group of astronomers uh in the United
• 27:54
  States measured the intrinsic brightness
• 27:57
  of a particular kind of variable star.
• 27:59
  one whose brightness varies uh but it
• 28:01
  varies in a in a periodic way. And it
• 28:04
  turns out that there's a relationship
• 28:05
  between how frequently it varies and
• 28:08
  what the intrinsic brightness is. And
• 28:10
  you usually take it at peak brightness
• 28:11
  or minimum brightness, whichever it
• 28:13
  doesn't doesn't really matter as long as
• 28:14
  you know what it is. And so that's the
• 28:17
  timehonored way of working out how far
• 28:20
  away galaxies are. uh to look for these
• 28:23
  variable stars and then basically uh
• 28:27
  look at um uh you know how bright they
• 28:30
  look to us and from that work out the
• 28:32
  distance. Uh and that lets you produce a
• 28:35
  value for what we call the Hubble
• 28:36
  constant which is the number that
• 28:40
  basically tells you how fast the
• 28:42
  universe is expanding. Uh the Hubble
• 28:45
  constant is in units of kilometers/s per
• 28:48
  mega par. But we don't really need to
• 28:50
  worry about that because at the moment
• 28:52
  all we're interested in is the number.
• 28:54
  And so until now uh the best estimates
• 28:58
  uh from the standard candles in other
• 29:00
  words the sephiid variables have come
• 29:03
  out at uh about 74 kilometers/s mega
• 29:07
  parc. But then the standard ruler method
• 29:10
  is uh looking back at the flash of the
• 29:13
  big bang, the cosmic microwave
• 29:14
  background radiation which we see uh as
• 29:17
  it was about 13 billion years ago. And
• 29:20
  there are features in that variation
• 29:22
  which uh have separations that we know
• 29:26
  would be characteristic of a certain the
• 29:29
  particular time and and what we're
• 29:31
  talking about here when I say features I
• 29:33
  mean peaks and troughs in the
• 29:35
  temperature of the big bang. effectively
• 29:37
  what you're looking at. Um and from that
• 29:39
  you can also deduce the Hubble constant
• 29:42
  the expansion rate as it is today. Uh
• 29:44
  but the answer you get from that is 67.5
• 29:48
  kilometers/s per mega par.
• 29:50
  >> Yeah.
• 29:51
  >> Uh which is round about 6 and a half
• 29:53
  kilometers/s per mega par different from
• 29:56
  the other one. And that is now we're in
• 29:58
  such a precise era that now now has
• 30:01
  people worried. Um so what's happened?
• 30:04
  Well, the same team who've done a huge
• 30:07
  amount of this work in the past led by
• 30:10
  um Dr. Wendy Free Freriedman, one of the
• 30:13
  big names in this kind of science in the
• 30:15
  United States. Uh Wendy and her team
• 30:18
  have used our new toy, the web, the
• 30:23
  James Web Space Telescope. Uh
• 30:25
  >> we always knew it would it would solve
• 30:27
  this problem.
• 30:28
  >> We knew it would certainly help. It
• 30:30
  would either make it worse or it would
• 30:32
  solve it. And yeah, you're right. to cut
• 30:34
  to the chase, it's probably solved it
• 30:35
  because it's now looking as though the
• 30:39
  method um is more like that, you know,
• 30:43
  the method where you measure the
• 30:44
  brightness of these variable stars is
• 30:46
  giving an answer more like 70
• 30:47
  kilometers/s per mega parc which is much
• 30:50
  closer to that 67.5 that you get from
• 30:52
  the cosmic microwave background
• 30:54
  radiation. And it turns out that when
• 30:56
  you think about the the error uh
• 30:59
  potential error of both of them, then it
• 31:01
  overlaps. So in that regard, you've got
• 31:04
  something that falls within the error
• 31:05
  bounds of both of these methods. And so
• 31:08
  maybe we are seeing the right answer at
• 31:10
  last.
• 31:10
  >> So it it basically brings it back to an
• 31:12
  average.
• 31:14
  >> That's right. Methods. Yeah.
• 31:16
  >> Yes. Yeah. You know when I started my
• 31:19
  career, Andrew, um there were two camps
• 31:23
  uh and basically they were using similar
• 31:26
  methods. uh one said that the uh Hubble
• 31:29
  constant was 50 kilometers/s per mega
• 31:31
  per second. The other said it was 100
• 31:33
  kilometers/s per mega per second. They
• 31:35
  were both right.
• 31:37
  They thought they were both right and it
• 31:39
  turned out that the the answer the real
• 31:41
  answer was the average of the 70 or 75
• 31:44
  for that.
• 31:45
  >> There you go. Um pretty simple solution
• 31:48
  at the end of the day, but a lot of hard
• 31:50
  work went into went in finding it and we
• 31:53
  yeah we hope that's that resolves the
• 31:55
  Hubble tension. It would be great.
• 31:56
  Hopefully
• 31:57
  >> cosmic crash disappeared. Yeah.
• 31:59
  >> Yeah. I I wouldn't be surprised though
• 32:01
  in months to come somebody comes up with
• 32:03
  a debunking theory.
• 32:05
  >> Uh well, there you go.
• 32:07
  >> It could happen. It could happen. But um
• 32:09
  at this point in time, looks like it
• 32:12
  might have been resolved. This has been
• 32:14
  frustrating for a long time, but u may
• 32:16
  may be as simple as Oh, hang on a sec.
• 32:18
  >> You're both right, and here's why.
• 32:20
  >> Yeah. Yeah.
• 32:21
  >> Yeah. Um that's stories on
• 32:23
  scitecdaily.com.
• 32:25
  Um question without notice, Fred, that's
• 32:27
  come through from one of our live
• 32:29
  viewers. Uh Wayne, hi Wayne. Um this
• 32:32
  harks back to the snowball earth story
• 32:35
  we did. Uh Wayne asks, "I wonder how
• 32:38
  much bigger the diameter of a frozen
• 32:40
  earth would be to the current earth. Do
• 32:43
  we have any idea what that might have
• 32:45
  been?"
• 32:46
  >> Yeah, I it probably wasn't that much
• 32:48
  different. Um it um you know I mean at
• 32:52
  the moment a lot of that water's still
• 32:54
  there but it's wet.
• 32:56
  Uh and you know this is now it's it's
• 32:59
  turned into ice. So um it's not going to
• 33:02
  be it's certainly not going to be k um
• 33:05
  tens of kilometers different um it might
• 33:08
  be a few kilometers different um on
• 33:10
  average and I'm talking about the
• 33:12
  average uh but but I don't think it
• 33:14
  would uh you know it wouldn't have
• 33:15
  turned into a gas giant or anything like
• 33:17
  that. It's an interesting question
• 33:18
  though because we think it's because of
• 33:20
  frozen water out in the depths of the
• 33:22
  solar system adding to the mass of the
• 33:26
  gas giants as they were being formed. We
• 33:28
  think that is one reason why they became
• 33:30
  so big because they had enough bands to
• 33:32
  hold onto a a gas envelope. Um and so
• 33:36
  it's a good question to to ask that what
• 33:39
  difference would the ice make? But it
• 33:40
  but this is really just a surface layer
• 33:42
  of ice rather than a solid block of ice
• 33:45
  which may be at the core of the of the
• 33:47
  gas giants.
• 33:48
  >> Indeed. All right. Thank you, Wayne.
• 33:50
  Nice to get questions without notice
• 33:52
  while we're going out live during our
• 33:54
  recording sessions. Good to hear from
• 33:56
  you. Uh Fred, we're just about done.
• 33:58
  Thank you very much.
• 33:59
  >> A pleasure, Andrew. Good to talk and uh
• 34:02
  some interesting topics and there'll be
• 34:04
  more next week.
• 34:05
  >> Indeed there will. Thanks, Fred.
• 34:07
  Professor Fred Watson, astronomer at
• 34:08
  large. Don't forget to check us out
• 34:11
  online, spacenutspodcast.com,
• 34:13
  spacenuts.io,
• 34:14
  where you can check out the shop, maybe
• 34:16
  become a supporter of the podcast if
• 34:18
  you're interested. Um, just have a bit
• 34:20
  of a flick around. And if you follow us
• 34:23
  on social media, don't forget to like
• 34:24
  us, follow us, add us to your favorites
• 34:26
  list, or click the subscribe button
• 34:28
  depending on which platform it is. Uh,
• 34:32
  and uh, thanks to Hugh in the studio as
• 34:34
  always. And from me, Andrew Dunley, we
• 34:36
  will see you again soon on the very next
• 34:38
  episode of Space Nuts. Bye-bye.
• 34:41
  >> Space Nuts.
• 34:42
  >> You'll be listening to the Space Nuts
• 34:44
  podcast
• 34:46
  >> available at Apple Podcasts, Spotify,
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• 34:52
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