00:00:00 --> 00:00:03 this is Spacetime Series 28 episode 33
00:00:03 --> 00:00:05 for broadcast on the 17th of March
00:00:05 --> 00:00:09 2025 Coming up on Spaceime the world's
00:00:09 --> 00:00:11 oldest meteor impact crater discovered
00:00:11 --> 00:00:14 in Western Australia More potential
00:00:14 --> 00:00:17 locations for water ice on the moon and
00:00:17 --> 00:00:20 the super secret X37b space shuttle
00:00:20 --> 00:00:22 returns to Earth following its latest
00:00:22 --> 00:00:25 mission All that and more coming up on
00:00:25 --> 00:00:27 Spaceime
00:00:27 --> 00:00:45 Welcome to SpaceTime with Stuart
00:00:45 --> 00:00:48 Garry Scientists have uncovered what is
00:00:48 --> 00:00:50 now the world's oldest known meteor
00:00:50 --> 00:00:52 impact crater in Western Australia
00:00:52 --> 00:00:54 Remnants of the ancient 3 and a half
00:00:54 --> 00:00:56 billiony old structure were discovered
00:00:56 --> 00:00:57 in the north pole derm region of the
00:00:58 --> 00:01:00 Pilbur in the state's north The previous
00:01:00 --> 00:01:03 oldest known impact crater also in
00:01:03 --> 00:01:05 Western Australia was dated at 2.2
00:01:05 --> 00:01:08 billion years The new discovery reported
00:01:08 --> 00:01:10 in the journal Nature Communications
00:01:10 --> 00:01:12 could significantly redefine science's
00:01:12 --> 00:01:14 understanding of the origins of life and
00:01:14 --> 00:01:17 how the planet was formed and evolved
00:01:17 --> 00:01:19 One of the study's authors Tim Johnson
00:01:19 --> 00:01:20 from Curtain University says the
00:01:20 --> 00:01:22 structure challenges previous
00:01:22 --> 00:01:24 assumptions about Earth's ancient
00:01:24 --> 00:01:26 history Johnson and colleagues
00:01:26 --> 00:01:27 discovered the crater thanks to shatter
00:01:27 --> 00:01:29 cones distinctive rock formations that
00:01:29 --> 00:01:32 only form under the intense pressure of
00:01:32 --> 00:01:34 a meteor strike The shatter cones at the
00:01:34 --> 00:01:37 site about 40 km west of Marble Bar were
00:01:37 --> 00:01:39 formed when a meteor slammed into the
00:01:39 --> 00:01:43 area at more than 36 kmh
00:01:43 --> 00:01:45 Johnson says this impact would have been
00:01:45 --> 00:01:47 a major planetary event resulting in a
00:01:47 --> 00:01:50 crater more than 100 kilometers across
00:01:50 --> 00:01:51 which would have sent ejected debris
00:01:51 --> 00:01:53 high into the atmosphere eventually
00:01:53 --> 00:01:56 raining back down across the entire
00:01:56 --> 00:01:59 planet He says the face of the moon is
00:01:59 --> 00:02:01 proof that large impacts were common in
00:02:01 --> 00:02:03 the early history of the solar system
00:02:03 --> 00:02:05 But until now the absence of any truly
00:02:06 --> 00:02:07 ancient impact craters on Earth has
00:02:07 --> 00:02:09 meant they're largely ignored by
00:02:09 --> 00:02:11 geologists Johnson says this study
00:02:11 --> 00:02:13 provides a crucial piece of the puzzle
00:02:13 --> 00:02:15 of Earth's impact history and suggested
00:02:15 --> 00:02:17 there could be many more ancient craters
00:02:17 --> 00:02:20 yet to be discovered Uncovering this
00:02:20 --> 00:02:21 impact structure and finding more from
00:02:22 --> 00:02:24 the same period could also help explain
00:02:24 --> 00:02:26 how life began on Earth That's because
00:02:26 --> 00:02:28 impact craters generate environments
00:02:28 --> 00:02:30 friendly to microbial life such as hot
00:02:30 --> 00:02:33 water pools full of mineral nutrients
00:02:33 --> 00:02:35 Johnson says it also radically
00:02:35 --> 00:02:37 redefineses science's understanding of
00:02:37 --> 00:02:40 crust formation You see the tremendous
00:02:40 --> 00:02:42 amount of energy from this impact could
00:02:42 --> 00:02:44 have played a major role in shaping the
00:02:44 --> 00:02:47 Earth's early crust It does this by
00:02:47 --> 00:02:49 pushing one part of the crust under
00:02:49 --> 00:02:51 another or by forcing magma to rise from
00:02:51 --> 00:02:53 deep within the Earth's mantle up
00:02:53 --> 00:02:56 towards the surface It may even have
00:02:56 --> 00:02:58 contributed to the formation of large
00:02:58 --> 00:03:01 ancient geological structures stretching
00:03:01 --> 00:03:03 deep down into the planet that may well
00:03:03 --> 00:03:05 be the foundations of today's continents
00:03:05 --> 00:03:09 So in 2022 we published a paper in
00:03:09 --> 00:03:12 Nature suggesting that the Pilra caton
00:03:12 --> 00:03:15 ultimately may have formed above one of
00:03:15 --> 00:03:17 these giant impacts of the type that we
00:03:18 --> 00:03:19 see on the on the surface of the moon
00:03:19 --> 00:03:22 Those dark Luna Mariah the Imbrium
00:03:22 --> 00:03:24 crater you know there was very big
00:03:24 --> 00:03:25 impacts that hit the moon There was very
00:03:25 --> 00:03:27 big impacts that hit the Earth And we
00:03:27 --> 00:03:30 believed as I say that the Pilocraton
00:03:30 --> 00:03:32 could have been a consequence of these
00:03:32 --> 00:03:35 And we used at that time we found some
00:03:35 --> 00:03:37 evidence based on the chemical
00:03:37 --> 00:03:40 composition of these tiny sandsized
00:03:40 --> 00:03:42 grains of the mineral zirkon So zirkon
00:03:42 --> 00:03:44 is very very robust chemically and
00:03:44 --> 00:03:46 physically robust It also contains lots
00:03:46 --> 00:03:49 of radioactive uranium which decays over
00:03:49 --> 00:03:52 time for lead So we can date it and its
00:03:52 --> 00:03:55 host rocks very very accurately And we
00:03:55 --> 00:03:57 can also measure various trace elements
00:03:57 --> 00:04:00 and isotopes of oxygen and hapneium and
00:04:00 --> 00:04:02 other sorts of things in these zirkon
00:04:02 --> 00:04:04 grains to say something about how they
00:04:04 --> 00:04:07 might have formed and the processes Now
00:04:07 --> 00:04:09 that is all a bit esoteric and it's all
00:04:09 --> 00:04:12 sort of microscopic or nanocale science
00:04:12 --> 00:04:14 So it's very difficult for anybody to
00:04:14 --> 00:04:16 get their heads around really and I
00:04:16 --> 00:04:18 don't think very many if any people
00:04:18 --> 00:04:21 really believed that paper So we thought
00:04:21 --> 00:04:24 we would go up to the Pilra and try and
00:04:24 --> 00:04:26 look for some more macroscopic evidence
00:04:26 --> 00:04:28 if you like Could we find the crater or
00:04:28 --> 00:04:32 the crater a floor and we simply started
00:04:32 --> 00:04:35 our search right in the middle of the
00:04:35 --> 00:04:38 exposure of the most ancient rocks So
00:04:38 --> 00:04:40 part of the Pilraaton the most ancient
00:04:40 --> 00:04:42 core of it is called the east Pilra
00:04:42 --> 00:04:45 terrain and that is a curiously round
00:04:45 --> 00:04:48 set of exposures of rocks about 200 km
00:04:48 --> 00:04:51 across And in the middle of that is a
00:04:51 --> 00:04:53 structure called the North Pole Dome So
00:04:53 --> 00:04:56 we headed there and in particular to
00:04:56 --> 00:04:59 find this unusual layer called the
00:04:59 --> 00:05:02 Antarctic Creek member We were looking
00:05:02 --> 00:05:04 for that because that layer people had
00:05:04 --> 00:05:08 formerly found sper So sparials are
00:05:08 --> 00:05:12 quite simply the frozen droplets of melt
00:05:12 --> 00:05:15 that forms as a direct effect of the
00:05:15 --> 00:05:17 heat of the impact But they can also
00:05:17 --> 00:05:19 form as the result of volcanic eruptions
00:05:19 --> 00:05:21 But at least this layer had some
00:05:21 --> 00:05:24 evidence for a distal impact So we
00:05:24 --> 00:05:26 thought we would start there And we
00:05:26 --> 00:05:29 parked our four-wheel drives just off a
00:05:30 --> 00:05:31 dusty truck heading south from the main
00:05:31 --> 00:05:33 road where we thought these rocks might
00:05:33 --> 00:05:36 appear Three of us got out and had a
00:05:36 --> 00:05:37 wander around and we agreed to meet back
00:05:38 --> 00:05:39 at the vehicles an hour or so later And
00:05:40 --> 00:05:42 we found when we did meet back we
00:05:42 --> 00:05:44 thought we'd all found the same thing
00:05:44 --> 00:05:46 which is this feature called shatter
00:05:46 --> 00:05:48 cones in the rock And shatter cones are
00:05:48 --> 00:05:51 the only unequivocal evidence that you
00:05:51 --> 00:05:54 can see with a naked eye for a direct
00:05:54 --> 00:05:57 meteorite impact crater So shatter cones
00:05:57 --> 00:05:59 are known almost exclusively from what
00:05:59 --> 00:06:02 are called the central uplift of big
00:06:02 --> 00:06:04 craters So much like when you drop into
00:06:04 --> 00:06:06 water that drop hits the surface and
00:06:06 --> 00:06:08 then you have a rebound the drop comes
00:06:08 --> 00:06:10 back up Um that's exactly what happens
00:06:10 --> 00:06:13 with big craters So the impactor hits
00:06:13 --> 00:06:15 and then the center where you've had the
00:06:15 --> 00:06:19 maximum impact force rebounds and you
00:06:19 --> 00:06:21 get something called a central uplet And
00:06:21 --> 00:06:23 that's what we believe this whole big 20
00:06:23 --> 00:06:26 or 30 km wide dome in the middle of the
00:06:26 --> 00:06:29 East Pilra is And we found the evidence
00:06:29 --> 00:06:31 supporting that which was extremely
00:06:31 --> 00:06:34 lucky but very nice The Zirkons then
00:06:34 --> 00:06:36 gave you the date for that Yes So this
00:06:36 --> 00:06:38 layer Antarctic creek member it is
00:06:38 --> 00:06:42 called it's a very unusual very complex
00:06:42 --> 00:06:44 layer a whole mish mash of lots of
00:06:44 --> 00:06:46 different things including broken up
00:06:46 --> 00:06:49 bits of bassalt and shirts and these
00:06:49 --> 00:06:51 sperial layers and it's sitting in
00:06:51 --> 00:06:53 between a few kilometers of bassalt
00:06:53 --> 00:06:55 underneath it and a few kilometers of
00:06:55 --> 00:06:58 bassalt above it These shatter cones are
00:06:58 --> 00:07:01 developed right the way throughout this
00:07:01 --> 00:07:03 20 m or so thick layer called the
00:07:03 --> 00:07:05 Antarctic creek member But immediately
00:07:05 --> 00:07:07 above them are these beautiful pillow
00:07:07 --> 00:07:10 lavas So like giant toothpaste sort of
00:07:10 --> 00:07:12 squirted out which tell us that they
00:07:12 --> 00:07:15 were erupted underwater But there is no
00:07:15 --> 00:07:18 sign of shock at all in those rocks
00:07:18 --> 00:07:20 above And we traced them up for several
00:07:20 --> 00:07:21 tens of meters to try and look for
00:07:21 --> 00:07:23 shatter cones above where we found them
00:07:23 --> 00:07:26 and couldn't find any The Antarctic
00:07:26 --> 00:07:29 Creek member is also overlaining by
00:07:29 --> 00:07:31 these really complex carbonate breers
00:07:31 --> 00:07:34 that penetrate into it as dikes and big
00:07:34 --> 00:07:36 fractures So what we think we're looking
00:07:36 --> 00:07:39 at is the surface of the crater We're
00:07:39 --> 00:07:42 actually standing on the crater floors
00:07:42 --> 00:07:44 in this huge structure which is the
00:07:44 --> 00:07:46 central uplift of the crater So because
00:07:46 --> 00:07:49 we didn't find any shatter cones above
00:07:50 --> 00:07:52 we think the stratographic age of that
00:07:52 --> 00:07:54 layer the Antarctic creek member gives
00:07:54 --> 00:07:56 you the age of the impact and
00:07:56 --> 00:07:58 fortunately the geocchronologists of the
00:07:58 --> 00:08:00 geological society of Western Australia
00:08:00 --> 00:08:02 had already dated the rocks and there is
00:08:02 --> 00:08:06 a layer of felicit volcanic rocks below
00:08:06 --> 00:08:08 the shatter cone bearing horizon which
00:08:08 --> 00:08:11 has been dated by uraniumled ziron to be
00:08:11 --> 00:08:13 3.47 47 billion years old And the
00:08:13 --> 00:08:16 bassalts above there is a layer of
00:08:16 --> 00:08:18 feltic volcanics in those as well which
00:08:18 --> 00:08:21 has also been dated at 3.47 billion
00:08:21 --> 00:08:23 years old So that provides us with a
00:08:23 --> 00:08:26 stratographic age of 3.47 for the um
00:08:26 --> 00:08:27 shatter cone bearing horizon So we knew
00:08:27 --> 00:08:30 we had our age and we had our oldest
00:08:30 --> 00:08:33 impact breaker This discovery is really
00:08:33 --> 00:08:35 exciting because we know Earth was
00:08:35 --> 00:08:37 formed as a result of meteor and
00:08:37 --> 00:08:39 asteroid impacts It's called accretion
00:08:39 --> 00:08:41 There was a big one about 4.5 billion
00:08:41 --> 00:08:44 years ago which we call thea the moon
00:08:44 --> 00:08:46 Yes So we know this happens but there's
00:08:46 --> 00:08:48 also a thing with the earth called plate
00:08:48 --> 00:08:51 tectonics and also we have erosion and
00:08:51 --> 00:08:53 things like this So the early earth's
00:08:53 --> 00:08:55 history is something we know very little
00:08:55 --> 00:08:57 about This ancient impact must be
00:08:57 --> 00:08:59 telling us a lot about the history of
00:08:59 --> 00:09:02 our planet Absolutely Yes Yes I mean
00:09:02 --> 00:09:05 we've argued it's 2018 really where we
00:09:05 --> 00:09:07 first got into this that large impacts
00:09:07 --> 00:09:09 were absolutely fundamental to earth's
00:09:09 --> 00:09:12 early evolution as we can see they were
00:09:12 --> 00:09:13 on all the other silicate bodies in the
00:09:14 --> 00:09:15 unis solar system that we can see be
00:09:15 --> 00:09:18 they planets moons or asteroids as you
00:09:18 --> 00:09:20 say plate tectonics is an incredibly
00:09:20 --> 00:09:23 efficient way of recycling the surface
00:09:23 --> 00:09:25 the rigid surface of the earth the
00:09:25 --> 00:09:27 lithosphere and the crust back into the
00:09:27 --> 00:09:29 convecting mantle So most of the
00:09:29 --> 00:09:32 evidence is destroyed particularly given
00:09:32 --> 00:09:34 that most of the planet would have been
00:09:34 --> 00:09:36 oceanic and most of those impacts would
00:09:36 --> 00:09:38 have been into the ocean and and they've
00:09:38 --> 00:09:40 subsequently disappeared But we do have
00:09:40 --> 00:09:43 areas of really really truly ancient
00:09:43 --> 00:09:45 continental crust these so-called catons
00:09:46 --> 00:09:47 that occur in the middle of all of the
00:09:48 --> 00:09:50 continents and they started forming
00:09:50 --> 00:09:53 right at the tail end of what we know
00:09:53 --> 00:09:55 would have been an intense bombardment
00:09:55 --> 00:09:57 from the formation of the solar system 4
00:09:57 --> 00:10:00 1/2 billion years ago right up to 3 1/2
00:10:00 --> 00:10:02 billion years ago So we should be able
00:10:02 --> 00:10:04 to find evidence of these impacts and we
00:10:04 --> 00:10:06 think we do and we think they would have
00:10:06 --> 00:10:09 been fundamental to the processes
00:10:09 --> 00:10:11 operating then including how those
00:10:11 --> 00:10:14 catons might originally have come to be
00:10:14 --> 00:10:17 but also how for example the earliest
00:10:17 --> 00:10:18 mineral systems the earliest
00:10:18 --> 00:10:20 hydrothermal mineralization systems
00:10:20 --> 00:10:23 formed and perhaps even creating the
00:10:23 --> 00:10:25 ecological niches from which life
00:10:25 --> 00:10:27 eventually took a foothold and emerged
00:10:27 --> 00:10:30 to become us The catons themselves
00:10:30 --> 00:10:31 they're fascinating because they've
00:10:32 --> 00:10:33 given place like Western Australia where
00:10:34 --> 00:10:35 you are it's mineral wealth that's made
00:10:35 --> 00:10:37 at one of the richest places on earth
00:10:37 --> 00:10:40 quite literally Exactly So many of the
00:10:40 --> 00:10:43 mineral deposits things like gold and
00:10:43 --> 00:10:46 nickel and lithium even are found
00:10:46 --> 00:10:49 predominantly in these aranatons and at
00:10:49 --> 00:10:51 their margins and we don't think that is
00:10:52 --> 00:10:54 a coincidence So yes in incredibly
00:10:54 --> 00:10:56 important processes and incredibly
00:10:56 --> 00:10:59 important consequences for humankind I
00:10:59 --> 00:11:01 mean we argue that large impacts created
00:11:01 --> 00:11:03 the land masses on which all humankind
00:11:03 --> 00:11:06 walks and the life from which we evolve
00:11:06 --> 00:11:08 So they couldn't be more fundamental in
00:11:08 --> 00:11:11 our view The link between the cratons
00:11:11 --> 00:11:13 and meteor impact site is quite
00:11:14 --> 00:11:15 fascinating What's the idea that the
00:11:15 --> 00:11:18 asteroids slammed into the earth and it
00:11:18 --> 00:11:20 melted everything underneath and that
00:11:20 --> 00:11:21 went all the way deep into the went into
00:11:22 --> 00:11:23 the deep mantle because some of these
00:11:23 --> 00:11:26 cratons can can go close to the core
00:11:26 --> 00:11:27 mantle boundary that melted material
00:11:27 --> 00:11:30 just upworld because of the the lack of
00:11:30 --> 00:11:31 pressure and so it was able to upworld
00:11:31 --> 00:11:33 towards the surface towards the crust
00:11:33 --> 00:11:35 Absolutely That's the that's the key
00:11:35 --> 00:11:38 point this decompression The earth is a
00:11:38 --> 00:11:40 layered structure and we have this rigid
00:11:40 --> 00:11:42 lithosphere crust which is sitting on
00:11:42 --> 00:11:45 top of the convecting mantle underneath
00:11:45 --> 00:11:47 and the convecting mantle is primed to
00:11:47 --> 00:11:50 melt and think of it like slowmoving
00:11:50 --> 00:11:52 molasses or honey Yes You can also think
00:11:52 --> 00:11:54 of it as a bit like a champagne bottle
00:11:54 --> 00:11:56 if you like So the only thing that's
00:11:56 --> 00:11:59 stopping the molasses the convecting
00:11:59 --> 00:12:01 mantle from melting is the fact that
00:12:01 --> 00:12:03 it's got a a lid on it This lithosphere
00:12:03 --> 00:12:05 Okay So that's like the cork in the
00:12:05 --> 00:12:07 champagne bottle As soon as you remove
00:12:07 --> 00:12:09 that lithosphere or you remove the cork
00:12:09 --> 00:12:12 everything goes mad and your champagne
00:12:12 --> 00:12:13 starts squirting out the top It's
00:12:13 --> 00:12:15 exactly the same for the mantle If you
00:12:15 --> 00:12:17 remove the lithosphere in with a big
00:12:17 --> 00:12:19 impact then the underlying mantle will
00:12:19 --> 00:12:22 melt profusely and produce huge volumes
00:12:22 --> 00:12:25 of bassalt So you'll get something like
00:12:25 --> 00:12:27 an oceanic plateau So something like on
00:12:27 --> 00:12:29 Java or even Hawaii those sorts of
00:12:29 --> 00:12:32 things But because Earth had still
00:12:32 --> 00:12:34 retained its water it still had a
00:12:34 --> 00:12:36 hydrosphere and and that hydrosphere is
00:12:36 --> 00:12:39 still around You then offer yourself the
00:12:39 --> 00:12:42 possibility of reprocessing that thick
00:12:42 --> 00:12:45 basultic pile of rocks into more evolved
00:12:45 --> 00:12:48 continental rocks granics if you like So
00:12:48 --> 00:12:50 the pale colored rocks And once you've
00:12:50 --> 00:12:52 formed those pale colored rocks they're
00:12:52 --> 00:12:54 really stable because they're they're
00:12:54 --> 00:12:56 much less dense than the basil And they
00:12:56 --> 00:12:59 basically float and and stay around for
00:12:59 --> 00:13:01 billions of years as as we know they
00:13:01 --> 00:13:03 have And one of the fundamental things
00:13:03 --> 00:13:05 about platons one of the fundamental
00:13:05 --> 00:13:07 observations that anybody can make when
00:13:07 --> 00:13:09 looking on Google Earth or geological
00:13:09 --> 00:13:12 maps is that they are uncommonly round
00:13:12 --> 00:13:14 And you need to provide a decent
00:13:14 --> 00:13:16 explanation as to why that would be
00:13:16 --> 00:13:18 because it's important I think
00:13:18 --> 00:13:20 geologists have perhaps forgotten what
00:13:20 --> 00:13:22 we have traditionally been good at which
00:13:22 --> 00:13:24 is making straightforward observations
00:13:24 --> 00:13:27 mapping things and recognizing patterns
00:13:28 --> 00:13:29 and then trying to interpret those
00:13:29 --> 00:13:31 patterns That's exactly how we
00:13:31 --> 00:13:33 discovered plate tectonics the patterns
00:13:33 --> 00:13:36 of the magnetic reversals on the seabed
00:13:36 --> 00:13:38 allowed people to interpret those that
00:13:38 --> 00:13:41 they were sites of creation of new crust
00:13:41 --> 00:13:43 That's how geology came about in the
00:13:43 --> 00:13:45 first place an observation was made of
00:13:45 --> 00:13:48 rocks on a cliff and they noticed that
00:13:48 --> 00:13:51 Yeah it was folded over Exactly Exactly
00:13:51 --> 00:13:53 And it would have taken time for that
00:13:53 --> 00:13:55 folding to take place Of course Of
00:13:55 --> 00:13:57 course And and it's those fundamental
00:13:57 --> 00:13:59 observations that people interpret And
00:13:59 --> 00:14:01 of course you know way back in the 17th
00:14:01 --> 00:14:03 and 18th century we didn't have any
00:14:03 --> 00:14:05 machinery to measure isotopes or trace
00:14:05 --> 00:14:07 elements or anything like that It really
00:14:07 --> 00:14:09 was what you can see with your eyes and
00:14:09 --> 00:14:10 map out to try and make sense of that
00:14:10 --> 00:14:12 But just fundamental observations such
00:14:12 --> 00:14:15 as catton if you look at maps of the
00:14:15 --> 00:14:17 Pilra caton or even the old one of the
00:14:17 --> 00:14:20 oldestratons the slaveraton it's just
00:14:20 --> 00:14:22 uncommonly round a circular feature and
00:14:22 --> 00:14:24 then that's a very hard thing to do with
00:14:24 --> 00:14:27 plate tectonics plate tectonics features
00:14:27 --> 00:14:29 like spreading ridges or continental
00:14:29 --> 00:14:31 arcs like Japan and Indonesia they're
00:14:31 --> 00:14:33 all these big long linear features
00:14:33 --> 00:14:35 that's exactly what you would expect if
00:14:35 --> 00:14:37 you have rigid plates jostling against
00:14:38 --> 00:14:39 each other and where they meet that's
00:14:39 --> 00:14:41 where all the action is happening But
00:14:41 --> 00:14:42 you wouldn't expect plate tectonics to
00:14:42 --> 00:14:44 produce anything like a a circular
00:14:44 --> 00:14:46 structure You would expect that to
00:14:46 --> 00:14:49 result from either impacts or these
00:14:49 --> 00:14:51 mantle plumes that is the other sort of
00:14:51 --> 00:14:53 widely held This is the hot spots like
00:14:53 --> 00:14:56 Hawaii and Iceland Precisely Yes So in
00:14:56 --> 00:14:57 the earlier well the earth certainly
00:14:57 --> 00:14:59 would have been hotter and you might
00:14:59 --> 00:15:01 expect mental plumes to have been even
00:15:01 --> 00:15:03 more vigorously active but it just
00:15:03 --> 00:15:06 doesn't make sense when you compare the
00:15:06 --> 00:15:08 likelihood that the impacts could have
00:15:08 --> 00:15:09 given rise to the same thing That's
00:15:10 --> 00:15:12 Professor Tim Johnson from Curtain
00:15:12 --> 00:15:15 University and this is spacetime Still
00:15:15 --> 00:15:18 to come a new study suggests water ice
00:15:18 --> 00:15:20 may be present just a few centimeters
00:15:20 --> 00:15:22 below the lunar surface over a far wider
00:15:22 --> 00:15:24 area of the moon's polar regions than
00:15:24 --> 00:15:27 previously thought And the United States
00:15:27 --> 00:15:29 secret X37B space shuttle returns to
00:15:30 --> 00:15:31 Earth following its latest classified
00:15:31 --> 00:15:34 mission All that and more still to come
00:15:34 --> 00:15:50 on
00:15:50 --> 00:15:53 Spaceime A new study suggests that water
00:15:53 --> 00:15:55 ice may be present just a few
00:15:55 --> 00:15:57 centimeters below the lunar surface over
00:15:57 --> 00:15:59 a far greater area of the moon's polar
00:15:59 --> 00:16:02 regions than previously thought The
00:16:02 --> 00:16:03 findings reported in the journal
00:16:03 --> 00:16:05 communications earth and environment are
00:16:05 --> 00:16:07 based on observations by the Indian
00:16:07 --> 00:16:09 Chandrean 3 mission in
00:16:09 --> 00:16:12 2023 It showed that the moon's surface
00:16:12 --> 00:16:14 is covered by large yet highly localized
00:16:14 --> 00:16:17 variations in surface temperatures It's
00:16:17 --> 00:16:19 an important factor because future
00:16:19 --> 00:16:21 long-term exploration and habitation of
00:16:21 --> 00:16:23 the moon will depend on the availability
00:16:23 --> 00:16:25 of ice to provide water So far
00:16:25 --> 00:16:27 measurements have shown the presence of
00:16:27 --> 00:16:29 water ice in cold sinks These are the
00:16:29 --> 00:16:31 dark permanently shadowed floors of deep
00:16:31 --> 00:16:33 polar craters that never experience any
00:16:33 --> 00:16:35 sunlight The only previous direct
00:16:36 --> 00:16:37 measurements of lunar surface
00:16:37 --> 00:16:39 temperatures were taken way back in the
00:16:39 --> 00:16:42 1970s by the Apollo missions However
00:16:42 --> 00:16:43 those missions all landed near the
00:16:43 --> 00:16:45 equator where terrain slopes had little
00:16:45 --> 00:16:47 effect on temperature The sites were
00:16:48 --> 00:16:49 several thousand kilometers from the
00:16:49 --> 00:16:51 proposed southern polar landing sites
00:16:51 --> 00:16:53 now being selected for the future
00:16:53 --> 00:16:56 Artemis man missions The study's lead
00:16:56 --> 00:16:57 author Dugra Prasad from India's
00:16:58 --> 00:16:59 physical research laboratory analyzed
00:16:59 --> 00:17:01 temperature readings taken on the lunar
00:17:01 --> 00:17:04 surface and down to a depth of 10 cm by
00:17:04 --> 00:17:05 a temperature probe experiment aboard
00:17:06 --> 00:17:08 the Changeran 3 vicram lander which
00:17:08 --> 00:17:09 touched down right at the edge of the
00:17:09 --> 00:17:12 lunar south pole Brasard and colleagues
00:17:12 --> 00:17:13 found that temperatures at the landing
00:17:13 --> 00:17:16 site a sun-facing slope angle at about
00:17:16 --> 00:17:20 6° peaked at around 355 Kelvin that's 82
00:17:20 --> 00:17:23 degrees C and dropped to 105 Kelvin
00:17:23 --> 00:17:27 that's - 168° C during the lunar night
00:17:28 --> 00:17:30 However a lower peak temperature of 332
00:17:30 --> 00:17:34 Kelvin or 59° C was measured on a flat
00:17:34 --> 00:17:36 region just a meter away The authors
00:17:36 --> 00:17:39 then use this collected data to derive a
00:17:39 --> 00:17:41 model of how slope angle affects surface
00:17:41 --> 00:17:43 temperatures on the moon especially at
00:17:43 --> 00:17:44 higher lunar latitudes similar to the
00:17:44 --> 00:17:47 landing site The model indicated that
00:17:47 --> 00:17:49 for slopes facing away from the sun and
00:17:49 --> 00:17:51 towards the nearest pole a slope with an
00:17:51 --> 00:17:54 angle greater than 14° may well be cool
00:17:54 --> 00:17:56 enough for ice to accumulate close to
00:17:56 --> 00:17:58 the surface And this is similar to
00:17:58 --> 00:18:01 conditions at the lunar poles including
00:18:01 --> 00:18:02 those at the proposed landing sites for
00:18:02 --> 00:18:05 Artemus The authors therefore suggest
00:18:05 --> 00:18:06 that areas on the moon where the ice can
00:18:06 --> 00:18:09 form may be far more numerous and easier
00:18:09 --> 00:18:12 to access than previously thought This
00:18:12 --> 00:18:15 is spaceime Still to come America's
00:18:15 --> 00:18:18 super secret X37b space shuttle returns
00:18:18 --> 00:18:19 to Earth following its latest mission
00:18:20 --> 00:18:22 And later in the science report we may
00:18:22 --> 00:18:24 finally be a step closer to a once a
00:18:24 --> 00:18:27 year injection which could help prevent
00:18:27 --> 00:18:29 HIV infection All that and more coming
00:18:30 --> 00:18:46 up on
00:18:46 --> 00:18:49 Spaceime The United States Space Force's
00:18:49 --> 00:18:51 highly secretive X37B space shuttle has
00:18:51 --> 00:18:54 returned to Earth following a classified
00:18:54 --> 00:18:57 434-day orbital mission It was the
00:18:57 --> 00:18:58 seventh mission for the program which
00:18:58 --> 00:19:00 uses two of the wing space planes to
00:19:00 --> 00:19:03 undertake specialist orbital testing and
00:19:03 --> 00:19:05 reconnaissance operations The landing at
00:19:05 --> 00:19:07 the Vandenberg Space Force Base in
00:19:07 --> 00:19:09 California took place appropriately
00:19:09 --> 00:19:11 under the cover of darkness in the
00:19:11 --> 00:19:13 middle of the night and the touchdown
00:19:13 --> 00:19:15 wasn't publicly announced until several
00:19:15 --> 00:19:18 hours after its pre-dawn return The
00:19:18 --> 00:19:19 mission had launched aboard SpaceX
00:19:19 --> 00:19:21 Falcon Heavy rocket from NASA's Kennedy
00:19:22 --> 00:19:25 Space Center way back in December 2023
00:19:25 --> 00:19:27 While few details were released by Space
00:19:27 --> 00:19:29 Force mission managers they did say the
00:19:29 --> 00:19:31 flight successfully demonstrated the
00:19:31 --> 00:19:33 vehicle's ability to change orbits by
00:19:33 --> 00:19:35 using aerobreing that is atmospheric
00:19:35 --> 00:19:38 drag to slow down in the process saving
00:19:38 --> 00:19:41 valuable fuel And that's an important
00:19:41 --> 00:19:42 development because one of the big
00:19:42 --> 00:19:45 advantages of the X37B is its ability to
00:19:45 --> 00:19:48 easily change orbits making it difficult
00:19:48 --> 00:19:50 for the enemy to keep track of Following
00:19:50 --> 00:19:52 its deployment from the Falcon into a
00:19:52 --> 00:19:54 highly elliptical orbit the reusable
00:19:54 --> 00:19:56 space plane conducted what Space Force
00:19:56 --> 00:19:58 describes as space domain awareness
00:19:58 --> 00:20:00 technology experiments that aim to
00:20:00 --> 00:20:02 improve America's knowledge of the space
00:20:02 --> 00:20:05 environment Now that word salad suggests
00:20:05 --> 00:20:06 that one of its functions is close
00:20:06 --> 00:20:09 proximity inspector missions studying
00:20:09 --> 00:20:11 imaging and maybe even attaching spy
00:20:11 --> 00:20:14 equipment onto enemy satellites First
00:20:14 --> 00:20:16 launched back in 2010 the Boeing made
00:20:16 --> 00:20:18 autonomous spacecraft are based on a
00:20:18 --> 00:20:20 prototype originally developed to be
00:20:20 --> 00:20:22 transported into space in the payload
00:20:22 --> 00:20:24 bay of NASA's space shuttle fleet and
00:20:24 --> 00:20:25 then deployed on missions lasting well
00:20:26 --> 00:20:29 over 900 days And the previous X37B
00:20:29 --> 00:20:33 mission OTV6 lasted 98 days in orbit
00:20:33 --> 00:20:36 Genuine proof of concept This is
00:20:36 --> 00:20:52 spaceime
00:20:52 --> 00:20:54 And time now to take a brief look at
00:20:54 --> 00:20:56 some of the other stories making news in
00:20:56 --> 00:20:59 science this week with a science report
00:20:59 --> 00:21:01 Early stage trials suggesting that a
00:21:01 --> 00:21:04 once a year injection to prevent HIV may
00:21:04 --> 00:21:07 now be a step closer to fruition
00:21:07 --> 00:21:09 HIV is the human immuno deficiency virus
00:21:09 --> 00:21:13 which causes AIDS The findings reported
00:21:13 --> 00:21:15 in the Lancet medical journal found that
00:21:15 --> 00:21:17 one injection of the drug licamp into
00:21:17 --> 00:21:19 the muscle resulted in the compound
00:21:19 --> 00:21:20 remaining detectable in the blood for at
00:21:20 --> 00:21:24 least 56 weeks At the one-year mark the
00:21:24 --> 00:21:26 study found the drug was safe and that
00:21:26 --> 00:21:27 blood levels of the drug were still
00:21:27 --> 00:21:29 higher than those recorded in previous
00:21:29 --> 00:21:30 studies where the drug was shown to
00:21:30 --> 00:21:33 block HIV transmission However as a
00:21:33 --> 00:21:35 phase one study the trial didn't
00:21:35 --> 00:21:36 actually measure the drug's
00:21:36 --> 00:21:38 effectiveness at preventing HIV
00:21:38 --> 00:21:40 infection and so further clinical trials
00:21:40 --> 00:21:41 will be needed including with
00:21:41 --> 00:21:43 participants from more diverse
00:21:43 --> 00:21:45 population
00:21:45 --> 00:21:47 sets Scientists say the record-breaking
00:21:47 --> 00:21:50 high sea temperatures of 2023 and 24
00:21:50 --> 00:21:52 were strange but not totally unexpected
00:21:52 --> 00:21:54 when looking at climate models A report
00:21:54 --> 00:21:56 in the journal Nature's found that
00:21:56 --> 00:21:58 global sea surface temperatures reached
00:21:58 --> 00:22:00 record highs breaking the previous
00:22:00 --> 00:22:04 records by around 0.25° 25° C The sudden
00:22:04 --> 00:22:06 increase raised concerns that global
00:22:06 --> 00:22:08 warming might be accelerating faster
00:22:08 --> 00:22:10 than models had predicted However
00:22:10 --> 00:22:11 looking at observation-based statistical
00:22:12 --> 00:22:13 models the authors found the jump was
00:22:13 --> 00:22:16 considered to be a 1 in 512-year event
00:22:16 --> 00:22:19 relative to current warming trends This
00:22:19 --> 00:22:20 means that while such an anomaly would
00:22:20 --> 00:22:22 have been practically impossible without
00:22:22 --> 00:22:24 current global warming trends the events
00:22:24 --> 00:22:27 not entirely unexpected
00:22:27 --> 00:22:29 Paleontologists have discovered red
00:22:29 --> 00:22:31 dinosaur footprints hiding in plain
00:22:32 --> 00:22:34 sight at a central Queensland high
00:22:34 --> 00:22:36 school A report in the journal
00:22:36 --> 00:22:38 Historical Biology identified 66
00:22:38 --> 00:22:40 fossilized footprints on a boulder at
00:22:40 --> 00:22:42 the school representing one of the
00:22:42 --> 00:22:44 highest concentrations of dinosaur
00:22:44 --> 00:22:45 footprints per square meter ever
00:22:45 --> 00:22:48 documented in Australia The footprints
00:22:48 --> 00:22:51 are from 47 individual dinosaurs which
00:22:51 --> 00:22:53 passed across a patch of wet clay while
00:22:54 --> 00:22:55 walking along or crossing a waterway
00:22:56 --> 00:22:57 during the early Jurassic some 200
00:22:58 --> 00:23:00 million years ago The three-toed
00:23:00 --> 00:23:02 footprints belong to the ignore species
00:23:02 --> 00:23:04 Aurpus Scampus a small bipedal
00:23:04 --> 00:23:06 herbiviverous dinosaur between 15 and 50
00:23:06 --> 00:23:09 cm in length with long legs a chunky
00:23:09 --> 00:23:11 body short arms and a small head and
00:23:11 --> 00:23:13 beak The boulder containing the
00:23:13 --> 00:23:15 footprints was uncovered some 20 years
00:23:15 --> 00:23:17 ago at a local mine and then given to
00:23:17 --> 00:23:20 the local high school And it wasn't
00:23:20 --> 00:23:22 alone A second rock also containing
00:23:22 --> 00:23:24 dinosaur footprints from two different
00:23:24 --> 00:23:26 species was found decorating the mine's
00:23:26 --> 00:23:28 car park entrance while a third much
00:23:28 --> 00:23:30 smaller dinosaur footprint covered rock
00:23:30 --> 00:23:32 had been encased in resin and was being
00:23:32 --> 00:23:50 used in the office as a bookend
00:23:50 --> 00:23:53 and that's the show for now Spaceime is
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