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Asteroid or comet, dinosaur impact firestorms, crater discovery, and Q&A on exoplanets and satellites
Andrew Dunkley is joined by Professor Jonti Horner of the University of Southern Queensland for two tightly related Space Nuts conversations. The first explores how astronomy keeps blurring the lines between asteroids and comets, what new research says about the dinosaur-killing impact, and a surprising crater found by an amateur astronomer planning a trip. The second is a listener Q&A covering exotic exoplanet weather, space regulation, and whether planets can form without a star.
Key topics
In this episode, Andrew and Jonti explain why astronomy often uses tidy labels for objects that sit on a continuum, especially when the line between asteroid and comet gets blurry.
They discuss near-Earth object 1998 SH2, which appears to have comet-like activity despite looking asteroid-like for decades.
Jonti breaks down how outgassing can nudge a small body off its predicted path, revealing non-gravitational forces.
The dinosaur-killing impact is revisited with new modelling suggesting the first hours after impact may have included global firestorms, not just long-term climate collapse.
The show covers the terminology debate around meteor, meteorite, fireball, bolide, asteroid, and comet impact.
A Canadian amateur astronomer, Joel LePointe, is credited with spotting a likely impact crater while planning a camping and hiking trip using satellite imagery.
The newly identified crater near Lake Marcel in northern Quebec is described as about 390 million years old and roughly 25 kilometers wide.
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00:00:00 --> 00:00:02 Andrew Dunkley: Hello again and thank you for joining us on
00:00:02 --> 00:00:04 another episode of Space Nuts. My name is
00:00:04 --> 00:00:06 Andrew Dunkley, your host. It's great to have
00:00:06 --> 00:00:08 your company. I hope you're well and I hope
00:00:08 --> 00:00:10 you can stick around. We've got some really
00:00:10 --> 00:00:12 great storeys today. These are fascinating.
00:00:13 --> 00:00:16 Remember that asteroid impact that led to the
00:00:16 --> 00:00:18 loss of the dinosaurs, you know, happened a
00:00:18 --> 00:00:20 couple of weeks ago? Uh, well, uh, it
00:00:21 --> 00:00:23 may have been much worse than we first
00:00:23 --> 00:00:26 thought. Lost lots of, uh, crispy critters as
00:00:26 --> 00:00:28 a consequence. We'll explain all that. Uh,
00:00:28 --> 00:00:31 there was a near Earth asteroid discovered
00:00:31 --> 00:00:33 around 30 years ago. 30 years ago. Well, now
00:00:34 --> 00:00:37 new evidence suggests it may
00:00:37 --> 00:00:40 have been a comet. And I love
00:00:40 --> 00:00:43 this storey. This is about a Canadian amateur
00:00:43 --> 00:00:45 astronomer who was planning a trip online
00:00:45 --> 00:00:48 using, uh, using online maps. And
00:00:48 --> 00:00:51 he made a massive discovery. We'll tell you
00:00:51 --> 00:00:54 all about it on this episode of space nuts.
00:00:54 --> 00:00:56 Generic: 15 seconds. Guidance is internal.
00:00:56 --> 00:00:59 10, 9. Ignition
00:00:59 --> 00:01:00 sequence start.
00:01:00 --> 00:01:01 Jonti Horner: Space nuts.
00:01:01 --> 00:01:04 Generic: 5, 4, 2, 1, 2, 3, 4,
00:01:04 --> 00:01:07 Jonti Horner: 5, 5, 4, 3, 2, 1. Space
00:01:07 --> 00:01:07 nuts.
00:01:07 --> 00:01:09 Generic: Astronauts report it feels good.
00:01:10 --> 00:01:12 Andrew Dunkley: And joining us, uh, this time around
00:01:12 --> 00:01:15 with Fred Watson, gallivanting around chasing
00:01:15 --> 00:01:18 solar eclipses is Professor Jonty
00:01:18 --> 00:01:20 Horner, professor of Astrophysics at the
00:01:20 --> 00:01:21 University of Southern Queensland. Welcome
00:01:21 --> 00:01:22 back, Jonty.
00:01:22 --> 00:01:24 Jonti Horner: Oh, uh, thanks for having me. It's good to be
00:01:24 --> 00:01:26 the substitute Yorkshireman again.
00:01:26 --> 00:01:28 Andrew Dunkley: Yes, we've got a whole set of them.
00:01:30 --> 00:01:31 It's really good stuff.
00:01:31 --> 00:01:34 Um, now we've got some amazing
00:01:34 --> 00:01:37 storeys. I know you've been a very busy young
00:01:37 --> 00:01:40 fellow for, um. Well, since we last
00:01:40 --> 00:01:42 spoke to you, uh, you do your own sort of
00:01:42 --> 00:01:45 gallivanting, but we managed to nail you down
00:01:45 --> 00:01:47 for a couple of weeks, which is fantastic.
00:01:48 --> 00:01:50 Uh, let's get straight into it because, um,
00:01:51 --> 00:01:53 these storeys dovetail. Well, we've got an
00:01:53 --> 00:01:56 asteroid that
00:01:56 --> 00:01:58 may have been a comet. Then we've got an
00:01:58 --> 00:02:00 asteroid that hit Earth that seems, uh, to
00:02:00 --> 00:02:02 have done more damage than we thought. And
00:02:02 --> 00:02:04 then we've got a hole in the ground
00:02:04 --> 00:02:06 discovered while someone was planning a
00:02:06 --> 00:02:08 holiday. All kind of related.
00:02:08 --> 00:02:10 So let's get stuck into the, uh, first
00:02:10 --> 00:02:13 storey. A near Earth asteroid that
00:02:13 --> 00:02:16 was discovered 30 years ago they think might
00:02:16 --> 00:02:17 have been a comet.
00:02:18 --> 00:02:21 Jonti Horner: Yeah, this is a lovely storey and it ties
00:02:21 --> 00:02:23 into something that we've talked about in
00:02:23 --> 00:02:26 different lights previously when I've been on
00:02:26 --> 00:02:27 the show, and I'm sure Fred Watson spoken
00:02:27 --> 00:02:29 about it quite frequently as well, which is
00:02:29 --> 00:02:32 that, uh, very human need to break things up
00:02:32 --> 00:02:35 into manageable chunks, you know, so you
00:02:35 --> 00:02:37 go from being a child to being a teenager to
00:02:37 --> 00:02:38 being an adult and there's A miraculous day
00:02:38 --> 00:02:40 when you wake up and you're suddenly legally
00:02:40 --> 00:02:41 able to drive.
00:02:41 --> 00:02:41 Andrew Dunkley: Yes.
00:02:41 --> 00:02:43 Jonti Horner: And in different countries, that's a
00:02:43 --> 00:02:45 different debt. But we all have it. But
00:02:45 --> 00:02:47 fundamentally, you're not really any
00:02:47 --> 00:02:49 different as a person the day before that and
00:02:49 --> 00:02:51 the day after it. What we're doing is we're
00:02:51 --> 00:02:53 breaking up this kind of continuum of human
00:02:53 --> 00:02:56 experience into chunks, where we group things
00:02:56 --> 00:02:58 that are similar together and we put things
00:02:58 --> 00:03:00 that are more different into separate groups.
00:03:00 --> 00:03:02 And I've talked about this in the past when
00:03:02 --> 00:03:04 we've talked about the difference between
00:03:04 --> 00:03:07 planets and stars and that amazing middle
00:03:07 --> 00:03:09 ground that are brown dwarfs, where in
00:03:09 --> 00:03:12 effect, you've actually got objects of all
00:03:12 --> 00:03:14 sizes from the size of a grain of sand,
00:03:14 --> 00:03:16 actually from the size of a single atom or a
00:03:16 --> 00:03:18 single subatomic particle, all the way up to
00:03:18 --> 00:03:21 the biggest galaxies and beyond in this kind
00:03:21 --> 00:03:24 of continuum of sizes. But you go through
00:03:24 --> 00:03:26 kind of rock to planet to brown dwarf to
00:03:26 --> 00:03:29 star. And we put these arbitrary divisions in
00:03:29 --> 00:03:31 so that we can group things that look similar
00:03:31 --> 00:03:34 together and study them to make life easier.
00:03:35 --> 00:03:37 And we talked about that, of course, in the
00:03:37 --> 00:03:39 context of Pluto, with the whole thing of
00:03:39 --> 00:03:41 when is a planet not a planet, when it's a
00:03:41 --> 00:03:43 dwarf planet, and why all that happened.
00:03:43 --> 00:03:45 That's exactly the same kind of thing. In my
00:03:45 --> 00:03:46 kind of contextualization, that was the right
00:03:46 --> 00:03:48 decision. That's a hill I'll quite happily
00:03:48 --> 00:03:50 plant my flag on. But
00:03:51 --> 00:03:53 Pluto's like the gangly teenager. From a
00:03:53 --> 00:03:54 distance, it looks big and like a serious
00:03:54 --> 00:03:56 adult, but it's still not very good at
00:03:56 --> 00:03:57 tidying its room up. That's the kind of
00:03:57 --> 00:04:00 analogy you there. This
00:04:00 --> 00:04:02 whole storey is another one of those same
00:04:02 --> 00:04:04 things. If we had been talking
00:04:05 --> 00:04:08 300 years ago, people would have been
00:04:08 --> 00:04:09 familiar with comets, at least the bright
00:04:09 --> 00:04:11 ones. You know, things that get bright enough
00:04:11 --> 00:04:13 to see with the naked eye that have a glowy
00:04:13 --> 00:04:15 coma and a tail. They appear briefly, then
00:04:15 --> 00:04:18 vanish forever. And we had great comets a
00:04:18 --> 00:04:20 couple of times in the last few years, on
00:04:20 --> 00:04:22 average one per decade. But it's a bit hit
00:04:22 --> 00:04:24 and miss. And the idea is, with modern
00:04:24 --> 00:04:27 scientific knowledge, what you're seeing when
00:04:27 --> 00:04:29 you get that phenomenon is a big dirty
00:04:29 --> 00:04:31 snowball or a snowy dirt ball that's whizzing
00:04:31 --> 00:04:33 around the sun on this hugely elongated
00:04:33 --> 00:04:36 orbit. When it's far from the sun and it's
00:04:36 --> 00:04:38 nice and cold, we just don't see it. You'd
00:04:38 --> 00:04:39 need the biggest telescopes on the world
00:04:39 --> 00:04:41 because you've just got this little thing
00:04:41 --> 00:04:44 reflecting a bit of sunlight. But when it
00:04:44 --> 00:04:46 comes near to the sun, its surface gets hot.
00:04:47 --> 00:04:50 The volatile material on it gets too hot to
00:04:50 --> 00:04:53 still be solid, so turns into gas. And
00:04:53 --> 00:04:55 that gas erupts from the surface, carrying
00:04:55 --> 00:04:57 with it dust, shrouds that snowball
00:04:58 --> 00:05:00 in what's called a coma, a big spherical
00:05:00 --> 00:05:03 cloud of gas. And then the solar wind pushes
00:05:03 --> 00:05:04 the gas and dust away from the sun and you
00:05:04 --> 00:05:07 get the tails. And so a comet, as we see
00:05:07 --> 00:05:10 it, is pretty big, can be millions or
00:05:10 --> 00:05:12 tens of kilometres, tens of millions of
00:05:12 --> 00:05:15 kilometres across, which is this huge amount
00:05:15 --> 00:05:17 of gas and dust floating around in the solar
00:05:17 --> 00:05:19 system, all given off by an icy,
00:05:19 --> 00:05:22 rocky, rubbly object only a few kilometres
00:05:22 --> 00:05:25 across in the head. And that's a comet. So
00:05:25 --> 00:05:27 it's basically something that has activity
00:05:27 --> 00:05:29 that out gases as it goes around the sun.
00:05:29 --> 00:05:30 Andrew Dunkley: Yep.
00:05:31 --> 00:05:33 Jonti Horner: 19. In 1801, sorry came along
00:05:34 --> 00:05:37 and Giuseppe Piazzi found Ceres, which
00:05:37 --> 00:05:39 was an object between the orbits of Mars and
00:05:39 --> 00:05:41 Jupiter. And he found it because they were
00:05:41 --> 00:05:43 looking for a planet, because people had
00:05:43 --> 00:05:46 suggested that might just be that there's a
00:05:46 --> 00:05:47 planet between Mars and Jupiter. So the
00:05:47 --> 00:05:50 celestial police were looking, but Piazzi got
00:05:50 --> 00:05:51 there first and that was the first of the
00:05:51 --> 00:05:54 asteroids. And over the decades, and
00:05:54 --> 00:05:56 the couple of centuries that followed, one
00:05:56 --> 00:05:59 object became four, became tens,
00:05:59 --> 00:06:02 became hundreds, became thousands, and
00:06:02 --> 00:06:04 nowadays it's over a million. And if we
00:06:04 --> 00:06:07 were talking kind of 30 or 40 years ago, we'd
00:06:07 --> 00:06:09 have had a very clear idea of what an
00:06:09 --> 00:06:12 asteroid is and that an asteroid is very
00:06:12 --> 00:06:14 different to a comet. So an asteroid is a
00:06:14 --> 00:06:17 rocky or metallic object that
00:06:17 --> 00:06:19 even when it gets near the sun, just stays as
00:06:19 --> 00:06:21 a rocky metallic object. No gas comes off it,
00:06:21 --> 00:06:23 just a lump of rock or rubble going around
00:06:23 --> 00:06:26 the sun. So
00:06:26 --> 00:06:28 rocky, rubbly object, icy object with loads
00:06:28 --> 00:06:30 of gas. You've got a comet, you've got an
00:06:30 --> 00:06:32 asteroid, very distinct.
00:06:33 --> 00:06:36 Now, water's got a bit more muddied for
00:06:36 --> 00:06:38 a few reasons over the last few decades.
00:06:38 --> 00:06:41 Firstly, you had objects called the
00:06:41 --> 00:06:44 Centaurs, which I studied for my PhD, that
00:06:44 --> 00:06:46 are big icy objects that are too far away
00:06:46 --> 00:06:49 from the sun most of the time to outgas. So
00:06:49 --> 00:06:51 got kind of asteroidal classifications and a
00:06:51 --> 00:06:53 couple of them got a bit nearer in and
00:06:53 --> 00:06:55 started out gassing, so got a dual classific.
00:06:57 --> 00:06:59 Chiron is the most famous. Chiron has both an
00:06:59 --> 00:07:01 asteroidal classification and, um, a cometary
00:07:01 --> 00:07:03 classification. Cause sometimes it looks like
00:07:03 --> 00:07:05 an asteroid, sometimes it looks like a comet.
00:07:06 --> 00:07:08 You then have things like the Geminid meteor
00:07:08 --> 00:07:10 shower every December, which is our best
00:07:10 --> 00:07:13 meteor shower. I love it dearly. Almost
00:07:13 --> 00:07:15 all of the meteor showers are produced by
00:07:15 --> 00:07:17 comets and we get them when we go through the
00:07:17 --> 00:07:18 dust that has been left behind by the
00:07:18 --> 00:07:20 activity of the comet when it was out
00:07:20 --> 00:07:22 gassing. But when they found the parent of
00:07:22 --> 00:07:25 the Geminids, it doesn't look like a comet,
00:07:25 --> 00:07:28 it's an asteroid. So the idea became that
00:07:28 --> 00:07:29 maybe it's a rock comet and it's getting so
00:07:29 --> 00:07:32 close to the sun it's shedding dust and we
00:07:32 --> 00:07:35 get the meteor shower. Then there were
00:07:35 --> 00:07:38 a couple of comets that were lost. And then
00:07:38 --> 00:07:40 many, many decades later, an asteroid was
00:07:40 --> 00:07:42 found that looked to be moving on the same
00:07:42 --> 00:07:44 orbit as a comet. And so maybe they're the
00:07:44 --> 00:07:47 same object and the comet has turned off. And
00:07:47 --> 00:07:48 when the comet has turned off and stopped
00:07:48 --> 00:07:51 making any gas, maybe it looks like an
00:07:51 --> 00:07:53 asteroid. So there's this blurring going on.
00:07:55 --> 00:07:57 In reality, what you've got is a
00:07:57 --> 00:08:00 continuum from rocky and metallic and nothing
00:08:00 --> 00:08:02 else on one end to incredibly icy on the
00:08:02 --> 00:08:04 other, and everything in between where you
00:08:04 --> 00:08:07 have more rock, less ice, more ice, less rock
00:08:07 --> 00:08:10 blurring together. That's a
00:08:10 --> 00:08:12 hell of a lengthy introduction, hell of a lot
00:08:12 --> 00:08:14 of background to give the context for this
00:08:14 --> 00:08:17 storey. So, in light of all that, back in
00:08:17 --> 00:08:20 1998 there was this near Earth
00:08:20 --> 00:08:22 asteroid discovered. It goes by the of 1998
00:08:23 --> 00:08:25 SH2 and it looks like a lump of rock.
00:08:25 --> 00:08:27 It goes around the sun every four or five
00:08:27 --> 00:08:30 years, whizzing around. It's been seen at a
00:08:30 --> 00:08:33 few apparitions since. And, um, that's all
00:08:33 --> 00:08:35 well and good. We know a few thousand Near
00:08:35 --> 00:08:37 Earth asteroids now and we're finding more
00:08:37 --> 00:08:39 and more of them all the time. And people are
00:08:39 --> 00:08:40 particularly interested because, of course,
00:08:40 --> 00:08:42 if they come near the Earth, there's a
00:08:42 --> 00:08:44 possibility that eventually one of them will
00:08:44 --> 00:08:46 come too near the Earth and will hit us and
00:08:46 --> 00:08:49 we'll have issues. And ask the dinosaurs
00:08:49 --> 00:08:50 about that. We can come back to that a little
00:08:50 --> 00:08:52 bit later on. So there's a lot of interest in
00:08:53 --> 00:08:56 learning more about near Earth asteroids and
00:08:56 --> 00:08:57 following them because the longer you observe
00:08:57 --> 00:08:59 them, the more accurately you know how
00:08:59 --> 00:09:01 they're moving. So the better you can predict
00:09:01 --> 00:09:04 into the future where they'll be and
00:09:04 --> 00:09:06 therefore rule out the chance of that object
00:09:06 --> 00:09:09 hitting the Earth. Uh, may also, of course,
00:09:09 --> 00:09:10 be interesting to people who want to mine
00:09:10 --> 00:09:12 that object in the future with off Earth
00:09:12 --> 00:09:14 mining that if you want to go mine it, you
00:09:14 --> 00:09:17 need to know where it is. Yeah, so
00:09:17 --> 00:09:20 that's this object. Brilliant. We found an
00:09:20 --> 00:09:20 Earth asteroid.
00:09:21 --> 00:09:24 Where it gets interesting for this storey
00:09:24 --> 00:09:26 is that, uh, back in August 2025,
00:09:27 --> 00:09:29 which is what, 27 years after this thing was
00:09:29 --> 00:09:32 discovered it had another close approach
00:09:32 --> 00:09:35 to Earth. Now, this wasn't like the
00:09:35 --> 00:09:37 forthcoming approach for the asteroid
00:09:37 --> 00:09:39 Apophis, which is going to come closer to us
00:09:39 --> 00:09:42 than geostationary satellites. This was close
00:09:42 --> 00:09:44 to astronomers and distant to everybody else.
00:09:44 --> 00:09:46 You're talking about the thing coming about 3
00:09:46 --> 00:09:48 million kilometres away at its closest
00:09:48 --> 00:09:51 approach. Now, that's relatively close, but
00:09:51 --> 00:09:53 it's not something to get particularly
00:09:53 --> 00:09:55 panicked about. That's nearly 10 times as far
00:09:55 --> 00:09:57 away as the moon is, about 8 times as far
00:09:57 --> 00:10:00 away as the Moon is. But it's near enough
00:10:00 --> 00:10:01 that if you want to learn more about the
00:10:01 --> 00:10:03 asteroid, what you can do is you can get the
00:10:03 --> 00:10:06 planetary radar, uh, that they used to beam
00:10:06 --> 00:10:08 radar, uh, out into space and bounce it off
00:10:08 --> 00:10:10 things and get it back. Yeah, to try and
00:10:10 --> 00:10:13 bounce radar, uh, off this asteroid
00:10:13 --> 00:10:15 to get an image of what its shape is, to
00:10:15 --> 00:10:17 learn about its rotation and figure out how
00:10:17 --> 00:10:20 big it is. Because even with the biggest
00:10:20 --> 00:10:23 telescopes on the planet, something like this
00:10:23 --> 00:10:26 is always just a single pixel. You can't zoom
00:10:26 --> 00:10:28 in. So what they did was they got the
00:10:28 --> 00:10:31 planetary radar, uh, sent radar out to this
00:10:31 --> 00:10:32 object and missed
00:10:34 --> 00:10:37 a little bit. Embarrassing as you do, it
00:10:37 --> 00:10:39 wasn't quite where it was supposed to be.
00:10:40 --> 00:10:41 So based on all those historical
00:10:41 --> 00:10:44 observations, you can predict into the future
00:10:44 --> 00:10:47 where the asteroid will be based purely on
00:10:47 --> 00:10:49 the gravity of all the planets. It's getting
00:10:49 --> 00:10:51 pulled around by the Earth, uh, and Venus,
00:10:51 --> 00:10:53 Jupiter, everything's pulling and tugging on
00:10:53 --> 00:10:56 it. And you can in a very prescriptive way
00:10:56 --> 00:10:57 run its orbit forward in time and say where
00:10:57 --> 00:11:00 it will be in the future if the only thing
00:11:00 --> 00:11:02 acting on it is gravity.
00:11:03 --> 00:11:06 But it wasn't where it should be. Uh, the
00:11:06 --> 00:11:08 fact it wasn't where it should be says
00:11:08 --> 00:11:10 something else is happening as well.
00:11:10 --> 00:11:12 Something else is happening to push it around
00:11:12 --> 00:11:14 now. So at this point, sometimes that we get
00:11:14 --> 00:11:17 the, oh, well, it must be an alien spaceship
00:11:17 --> 00:11:19 thing happening. That's exactly what's
00:11:19 --> 00:11:21 happened in the past with people suggesting
00:11:21 --> 00:11:24 there's maybe something more going on that
00:11:24 --> 00:11:26 actually hasn't happened with this one, which
00:11:26 --> 00:11:28 is really nice to see. But what
00:11:28 --> 00:11:31 that being out of position tells you is that
00:11:31 --> 00:11:33 there are non gravitational forces acting on
00:11:33 --> 00:11:36 this thing. Something other than gravity is
00:11:36 --> 00:11:38 happening to push it around a little bit.
00:11:39 --> 00:11:41 Now, M. If we rewind to comets for a little
00:11:41 --> 00:11:43 bit. I remember when I was a teenager back in
00:11:43 --> 00:11:46 the early 1990s, we had Comet Swift Tuttle
00:11:46 --> 00:11:48 came past and, um, Comet Swift Tuttle's a
00:11:48 --> 00:11:51 parent of the Perseid shower. And, um, that
00:11:51 --> 00:11:52 was kind of a relief because at, uh, Its
00:11:52 --> 00:11:54 previous apparition, Comet Swift Tuttle, had
00:11:54 --> 00:11:57 been seen widely observed and had been
00:11:57 --> 00:11:59 predicted that it would come back in about
00:11:59 --> 00:12:01 120 years. It would come back in the early
00:12:01 --> 00:12:03 1980s and it didn't show up.
00:12:04 --> 00:12:06 M which was a bit weird because this is a
00:12:06 --> 00:12:08 bigger and more active comet than Comet
00:12:08 --> 00:12:10 Hallie. It's probably the biggest of the
00:12:10 --> 00:12:12 comets with a period less than 200 years.
00:12:12 --> 00:12:15 Pretty epic object. And it came back 10
00:12:15 --> 00:12:17 years later. Now, by the time it came back,
00:12:17 --> 00:12:18 people had figured out kind of what was going
00:12:18 --> 00:12:21 on, had realised that it was going to be
00:12:21 --> 00:12:23 late. But part of the complexity there
00:12:24 --> 00:12:25 was that, uh, because this is quite an active
00:12:25 --> 00:12:28 comet, when it's ejecting gas and dust to
00:12:28 --> 00:12:31 space, that process acts like a
00:12:31 --> 00:12:33 rocket engine that pushes it around. So it's
00:12:33 --> 00:12:36 ejecting gas in one direction and that exerts
00:12:36 --> 00:12:37 a force pushing the nucleus in another.
00:12:38 --> 00:12:41 And that is not a predictable thing in
00:12:41 --> 00:12:44 that every time a comet comes around the sun,
00:12:44 --> 00:12:46 its rotation will be a bit different. Some
00:12:46 --> 00:12:48 active areas will turn off and some will turn
00:12:48 --> 00:12:51 on. So while you can get a general trend and
00:12:51 --> 00:12:53 you can make loose predictions, there's
00:12:53 --> 00:12:55 always going to be a bit of uncertainty in
00:12:55 --> 00:12:57 where a comet will be in the future because
00:12:57 --> 00:12:59 it's got these forces pushing and nudging it
00:12:59 --> 00:13:02 around. You know, it's a bit like, I don't
00:13:02 --> 00:13:04 know if you could strap a few fireworks to a
00:13:04 --> 00:13:05 snowball and throw it up in the air. That's
00:13:05 --> 00:13:07 probably not very healthy to do. But you get
00:13:07 --> 00:13:08 the same kind of thing, they go off at
00:13:08 --> 00:13:11 different times and be pushed around all over
00:13:11 --> 00:13:13 the place. Um, interestingly, Comet Encke,
00:13:13 --> 00:13:15 which is a comet with the shortest non
00:13:15 --> 00:13:18 orbital period, has been seen every three and
00:13:18 --> 00:13:20 a half years, 3.3 years for more than 200
00:13:20 --> 00:13:22 years. And we've actually seen its orbital
00:13:22 --> 00:13:24 period get shorter and then get longer again
00:13:24 --> 00:13:26 as a direct result of the jets on its
00:13:26 --> 00:13:29 surface, uh, pushing it around and those jets
00:13:29 --> 00:13:31 changing the rotation direction of the
00:13:32 --> 00:13:34 comet. Loads of cool stuff there.
00:13:36 --> 00:13:39 So with that knowledge, you can look at this
00:13:39 --> 00:13:41 object, 1998 SH2.
00:13:41 --> 00:13:44 It's not where it's supposed to be. So that
00:13:44 --> 00:13:45 suggests that there's non gravitational
00:13:45 --> 00:13:48 forces happening. But whenever people have
00:13:48 --> 00:13:50 observed it in the past, it has looked inert.
00:13:50 --> 00:13:52 Uh, it's looked like an asteroid.
00:13:53 --> 00:13:56 What that suggests is that it is active.
00:13:56 --> 00:13:58 It's got some outgassing happening, but at
00:13:58 --> 00:14:01 such low levels that it wasn't possible to
00:14:01 --> 00:14:04 detect them before. So that was a clue
00:14:04 --> 00:14:06 that seems a really likely storey.
00:14:06 --> 00:14:08 So scientists go away and they do a couple of
00:14:08 --> 00:14:11 things. Firstly, they look for pre discovery
00:14:11 --> 00:14:13 observations of this, you know, times when
00:14:13 --> 00:14:16 there was a photographic plate made 50 years
00:14:16 --> 00:14:17 ago that just happened to have the object in
00:14:17 --> 00:14:20 the field of view so you can get a longer
00:14:20 --> 00:14:22 period of knowledge of how it's moved.
00:14:22 --> 00:14:22 Andrew Dunkley: Yeah.
00:14:23 --> 00:14:25 Jonti Horner: And um, with these really accurate
00:14:25 --> 00:14:27 observations, you can tell that it has been
00:14:27 --> 00:14:29 misbehaving for a long time. It's getting
00:14:29 --> 00:14:32 pushed and nudged around. What then
00:14:32 --> 00:14:34 happened was they used some of the really
00:14:34 --> 00:14:36 biggest telescopes in the world to take a
00:14:36 --> 00:14:39 look at it and detect just a tiny hint of gas
00:14:39 --> 00:14:42 being emitted, tiny little wisp.
00:14:42 --> 00:14:44 And so you put all that together and um, this
00:14:44 --> 00:14:46 thing is probably, of all the comets we know
00:14:46 --> 00:14:49 in the solar system, the least active that we
00:14:49 --> 00:14:51 currently know of. But it is exhibiting
00:14:51 --> 00:14:54 cometary behaviour. So it's another object
00:14:54 --> 00:14:56 really straddling the boundary. And it's
00:14:56 --> 00:14:58 fascinating. It'll be wonderful to learn more
00:14:58 --> 00:15:01 about it. But it's fascinating too,
00:15:02 --> 00:15:04 because here's the thing that looks like an
00:15:04 --> 00:15:06 asteroid, sounds like an asteroid. It does
00:15:06 --> 00:15:07 everything you'd expect an asteroid to do,
00:15:08 --> 00:15:10 except it's wibbling and misbehaving a bit.
00:15:10 --> 00:15:13 Now, if you're finding hundreds and thousands
00:15:13 --> 00:15:14 of near Earth asteroids and you want to know
00:15:14 --> 00:15:17 whether the Earth's safe, well, if you see
00:15:17 --> 00:15:19 something that's an asteroid, you can predict
00:15:19 --> 00:15:22 where it is with gravity going forward, the
00:15:22 --> 00:15:24 Earth's safe. What this is telling you is
00:15:24 --> 00:15:27 that, uh, gravity may not be enough. So you
00:15:27 --> 00:15:28 can't just say, well, it looks like it'll be
00:15:28 --> 00:15:31 safe, we'll stop looking. Because if this
00:15:31 --> 00:15:33 object's unpredictable, what about all the
00:15:33 --> 00:15:34 other ones we're finding too?
00:15:34 --> 00:15:36 Andrew Dunkley: I was about to bring that up. There's got to
00:15:36 --> 00:15:37 be more than one.
00:15:38 --> 00:15:40 Jonti Horner: Oh, absolutely. Um, we found
00:15:41 --> 00:15:43 quite a few of these over the years now in
00:15:43 --> 00:15:45 various circumstances. My favourite
00:15:46 --> 00:15:48 really is the Taurid stream of debris. We get
00:15:48 --> 00:15:50 the Taurid meteor shower every year from
00:15:50 --> 00:15:52 about September to December. We've got the
00:15:52 --> 00:15:54 northern and southern Taurids. We also get a
00:15:54 --> 00:15:57 daytime meteor shower in June called the Beta
00:15:57 --> 00:15:59 Taurids. Result is we spend about
00:15:59 --> 00:16:02 four months of every 12 passing
00:16:02 --> 00:16:05 through this enormous broad swath of debris
00:16:05 --> 00:16:07 where on any given night, when the meteor
00:16:07 --> 00:16:09 shower is active even at its peak ulcely,
00:16:09 --> 00:16:12 four or five meteors an hour, the debris is
00:16:12 --> 00:16:14 very spread out. But because the Earth spends
00:16:14 --> 00:16:16 so long going through it, we get more debris
00:16:16 --> 00:16:18 from that stream than all other meteor
00:16:18 --> 00:16:21 showers combined over the course of a year.
00:16:22 --> 00:16:25 At the core of that is Comet Encke, which is
00:16:25 --> 00:16:27 that comet with a 3.3 year period, but
00:16:27 --> 00:16:30 also a huge amount of other rubble and
00:16:30 --> 00:16:33 debris. There's lots and lots of asteroids or
00:16:33 --> 00:16:35 things that behave like asteroids moving
00:16:35 --> 00:16:37 around in the storage stream. And the idea is
00:16:37 --> 00:16:40 that this was a, uh, mega comet 20 or
00:16:40 --> 00:16:43 30 years ago that fell apart,
00:16:43 --> 00:16:46 giving us this stream of debris. Comet Encke
00:16:46 --> 00:16:48 was probably behaving like an asteroid if
00:16:48 --> 00:16:50 he'd found it a thousand years ago. But
00:16:50 --> 00:16:53 something happened 250 years ago to wake it
00:16:53 --> 00:16:55 up and it started behaving like a comet and
00:16:55 --> 00:16:58 we see it as a comet. And the other asteroids
00:16:58 --> 00:17:01 in that stream are currently dormant and
00:17:01 --> 00:17:03 there's a load of them. So it's likely in the
00:17:03 --> 00:17:06 inner solar system that even just in the
00:17:06 --> 00:17:08 Taurid Stream, you're going to have hundreds,
00:17:08 --> 00:17:10 if not thousands of objects just like
00:17:10 --> 00:17:13 1998 SH2 that straddle
00:17:13 --> 00:17:15 that boundary between the comet and the
00:17:15 --> 00:17:16 asteroid.
00:17:18 --> 00:17:20 Andrew Dunkley: Fair enough. And, uh, as a consequence of
00:17:20 --> 00:17:21 that, they've had to rename it.
00:17:23 --> 00:17:26 Jonti Horner: Yep. So it now has a cometary classification
00:17:26 --> 00:17:29 as well. What happens with comets is you
00:17:29 --> 00:17:32 get. When people find a comet,
00:17:32 --> 00:17:35 um, it's C, slash, then the year,
00:17:35 --> 00:17:37 ah, and then a catalogue number. So basically
00:17:37 --> 00:17:39 every comet gets a unique identifier. So we
00:17:39 --> 00:17:42 remember Chuchinshan Atlas, which,
00:17:42 --> 00:17:45 um. I'm trying to remember the correct ID for
00:17:45 --> 00:17:47 it, but it was, I think it was like 2023
00:17:47 --> 00:17:50 A, ah, 1 or something like that, A3. So
00:17:50 --> 00:17:52 the A means that it's discovered in the first
00:17:52 --> 00:17:54 fortnight of the year. 3 is the third object
00:17:54 --> 00:17:56 found in the first fortnight of the year.
00:17:56 --> 00:17:59 That tells you about the comet and then
00:17:59 --> 00:18:01 it's named after the discoverer in brackets.
00:18:02 --> 00:18:04 If the comet is seen at more than one
00:18:04 --> 00:18:06 apparition, the C gets changed to a P to show
00:18:06 --> 00:18:09 that it's periodic. In this
00:18:09 --> 00:18:12 case, because this already has
00:18:12 --> 00:18:15 an asteroidal name by which
00:18:15 --> 00:18:17 it's known, it's kept that, but they've added
00:18:17 --> 00:18:19 a P in front of it. So it's gone from being
00:18:19 --> 00:18:22 1998 SH2 to being
00:18:22 --> 00:18:25 P. 1998 SH2,
00:18:25 --> 00:18:28 um, will be interesting to see whether down
00:18:28 --> 00:18:29 the line they add the name of the discovery
00:18:29 --> 00:18:32 facility to it. Um, that wouldn't surprise
00:18:32 --> 00:18:34 me. That's been done for previous occasions
00:18:34 --> 00:18:36 where we've had an asteroid that became a
00:18:36 --> 00:18:38 comet. But it'll be interesting to see. But
00:18:38 --> 00:18:41 it's. I guess what I love about this is
00:18:41 --> 00:18:43 you get into the nitty gritty of it, but it's
00:18:43 --> 00:18:45 that reminder of the beautiful complexity
00:18:45 --> 00:18:47 we've got. There's so much more to learn.
00:18:48 --> 00:18:50 Andrew Dunkley: Absolutely, yes. Uh, it's a really good
00:18:50 --> 00:18:53 storey and, um, one worth reading up. You can
00:18:53 --> 00:18:55 do that@space.com or you can
00:18:55 --> 00:18:58 read the published findings in the journal
00:18:58 --> 00:19:01 Nature Astronomy. This is Space Nuts with
00:19:01 --> 00:19:03 Andrew Dunkley and Professor John T Horner.
00:19:06 --> 00:19:09 Jonti Horner: The crew of Artemis 2 now bound for the moon.
00:19:09 --> 00:19:11 Generic: Humanity's next great voyage begins.
00:19:12 --> 00:19:13 Jonti Horner: Space note Nuts.
00:19:13 --> 00:19:16 Andrew Dunkley: Let's move from a comet flying through
00:19:16 --> 00:19:19 space to a comet, uh, or an asteroid in this
00:19:19 --> 00:19:22 case, that stopped, uh, flying through space
00:19:22 --> 00:19:24 because a big planet called Earth got in the
00:19:24 --> 00:19:27 way. And the one
00:19:27 --> 00:19:29 that, um, is referred to as, uh,
00:19:30 --> 00:19:32 or creating the Chicxulub crater
00:19:33 --> 00:19:35 in what is now known, uh, as the Gulf of
00:19:35 --> 00:19:38 Mexico. Uh, and we even know the
00:19:38 --> 00:19:40 exact impact point because they've been down
00:19:40 --> 00:19:43 there and taken samples, uh, which was a very
00:19:43 --> 00:19:45 exciting storey when we covered that sometime
00:19:45 --> 00:19:47 back. But now they've taken another look at
00:19:47 --> 00:19:50 this, uh, and gone back to the very moment of
00:19:50 --> 00:19:53 impact and the few hours afterwards and
00:19:53 --> 00:19:56 decided by the look of it that this thing was
00:19:56 --> 00:19:58 much more brutal than
00:19:59 --> 00:20:00 we first envisaged.
00:20:02 --> 00:20:04 Jonti Horner: Absolutely. And this kind of ties in with the
00:20:04 --> 00:20:06 storeys that were told again. Back when I was
00:20:06 --> 00:20:09 a teenager, I remember hearing about the
00:20:10 --> 00:20:12 impact that killed the dinosaurs and storeys
00:20:12 --> 00:20:14 about what would have happened on the other
00:20:14 --> 00:20:17 side of the planet and the idea of firestorms
00:20:17 --> 00:20:18 and, you know, it was a hellish experience
00:20:18 --> 00:20:21 worldwide. But the way you'd normally hear
00:20:21 --> 00:20:23 this storey relatively recently is you had
00:20:23 --> 00:20:26 the impact. Things were bad in the vicinity
00:20:26 --> 00:20:28 of the impact. Shockwaves went out, tsunamis
00:20:28 --> 00:20:30 went out. So over a very large area, it was
00:20:30 --> 00:20:33 immediately fairly devastating. But
00:20:33 --> 00:20:35 there was a huge amount of dust and debris
00:20:35 --> 00:20:38 flung into the Earth's atmosphere, which led
00:20:38 --> 00:20:40 to this prolonged nuclear winter type event.
00:20:40 --> 00:20:42 You know, it blocked the sun, got really
00:20:42 --> 00:20:45 cold, the plants died, the animals died. Then
00:20:45 --> 00:20:47 when the clouds cleared, it got really,
00:20:47 --> 00:20:49 really nasty because you got this period of
00:20:49 --> 00:20:51 runaway global warming and hideous acid rain
00:20:51 --> 00:20:53 because the impact had hit rocks that were
00:20:53 --> 00:20:56 packed with carbon and sulphur
00:20:56 --> 00:20:58 carbonate and sulphate rocks, which led to,
00:20:58 --> 00:21:01 uh, carbonic and sulfuric acid
00:21:01 --> 00:21:04 rain. It led to an atmosphere super loaded
00:21:04 --> 00:21:06 with greenhouse gases. So it basically
00:21:06 --> 00:21:09 made the planet fairly hellish for a few tens
00:21:09 --> 00:21:11 of thousands of years, from one stage to the
00:21:11 --> 00:21:14 next to the next. But when I was
00:21:14 --> 00:21:16 younger, there were these storeys about while
00:21:16 --> 00:21:18 there were probably global firestorms. The
00:21:18 --> 00:21:20 idea that an impact halfway around the world
00:21:21 --> 00:21:23 could set fire to forests elsewhere.
00:21:24 --> 00:21:27 And in recent years I've not heard
00:21:27 --> 00:21:29 that storey told so much. It's kind of fallen
00:21:29 --> 00:21:31 a little bit out of fashion. But the new
00:21:31 --> 00:21:34 research that's been done here is kind of
00:21:34 --> 00:21:36 bringing that idea back into the picture.
00:21:37 --> 00:21:39 Now, the idea here is that you get this
00:21:40 --> 00:21:41 impactor that was probably about 10
00:21:41 --> 00:21:44 kilometres across, smacking into the Yukon
00:21:44 --> 00:21:47 Peninsula, creating a crater that was
00:21:47 --> 00:21:49 two to 300 kilometres in diameter.
00:21:50 --> 00:21:51 In doing that, it would have flung a huge
00:21:51 --> 00:21:54 amount of rocky material, vaporised material,
00:21:55 --> 00:21:57 out of the atmosphere. And a lot of that
00:21:57 --> 00:21:59 material would have travelled at speeds
00:21:59 --> 00:22:01 slower than the Earth's escape velocity to
00:22:01 --> 00:22:03 rain back down into the atmosphere. And when
00:22:03 --> 00:22:05 that material falls back into the atmosphere,
00:22:05 --> 00:22:07 it's travelling at speeds of kilometres per
00:22:07 --> 00:22:10 second, so it ablates like a
00:22:10 --> 00:22:11 fireball that we see in the sky, like a
00:22:11 --> 00:22:13 meteor. But you're not seeing one or two,
00:22:13 --> 00:22:15 you're seeing a huge deluge of material
00:22:15 --> 00:22:17 raining down all across the planet.
00:22:18 --> 00:22:21 Now, when these bits of material hit
00:22:21 --> 00:22:23 the atmosphere and ablate, what they're doing
00:22:23 --> 00:22:25 is they're taking the kinetic energy of their
00:22:25 --> 00:22:28 Martian and emitting, turning it into heat
00:22:28 --> 00:22:30 and light, which, you know, if you get a
00:22:30 --> 00:22:32 single small meteor, you're not gonna get
00:22:32 --> 00:22:35 sunburn from it. If you get something the
00:22:35 --> 00:22:36 size of the Chelyabinsk impact, people
00:22:36 --> 00:22:38 actually did get sunburn, um, from that, from
00:22:38 --> 00:22:41 the brightness of the flash. Now imagine,
00:22:41 --> 00:22:43 instead of having one Chelyabinsk impact,
00:22:43 --> 00:22:45 having this rain of material falling into the
00:22:45 --> 00:22:48 atmosphere all across the planet, creating
00:22:48 --> 00:22:50 this, what's described as a thermal pulse
00:22:51 --> 00:22:53 that has been discussed and
00:22:54 --> 00:22:55 previous models, things that have come out,
00:22:56 --> 00:22:58 suggested that that effect would have been
00:22:58 --> 00:23:01 like putting a grill on. It would have been
00:23:01 --> 00:23:03 really quite unpleasant for thin skinned
00:23:03 --> 00:23:04 animals that were exposed to it. You'd have
00:23:04 --> 00:23:07 got burned, you might even have got killed.
00:23:07 --> 00:23:09 But if you were, uh, underground or you were
00:23:09 --> 00:23:12 underwater, you'd have been able to live
00:23:12 --> 00:23:14 through it. I mean, you'd have lived to see
00:23:14 --> 00:23:16 all the other horrors that were coming from
00:23:16 --> 00:23:17 the impacts. It wasn't really a good news,
00:23:17 --> 00:23:19 Storey, but you'd have probably survived it.
00:23:20 --> 00:23:22 But the argument had been that that thermal
00:23:22 --> 00:23:24 pulse from that material coming into the
00:23:24 --> 00:23:26 atmosphere would not have got things hot
00:23:26 --> 00:23:29 enough to ignite things like grasses. You
00:23:29 --> 00:23:32 know, the tinder that you get that can start
00:23:32 --> 00:23:34 forest fires and things like this, which I
00:23:34 --> 00:23:36 think is why that idea of the global
00:23:36 --> 00:23:39 firestorms had gone away. What
00:23:39 --> 00:23:41 the new research has done is looking at
00:23:41 --> 00:23:43 fossil sites in North America, which must be
00:23:43 --> 00:23:45 remembered, was quite close to the impact,
00:23:46 --> 00:23:48 relatively speaking, on a global sense. They
00:23:48 --> 00:23:51 found this layer of spherules of material,
00:23:51 --> 00:23:53 which is a debris that rained back down to
00:23:53 --> 00:23:56 Earth, uh, in the fossil record and above it
00:23:56 --> 00:23:59 there's this very thin layer of silicate
00:23:59 --> 00:24:01 dust which must have fallen out at about the
00:24:01 --> 00:24:04 same time. Now the
00:24:04 --> 00:24:06 idea is that that silicate dust
00:24:07 --> 00:24:09 would have effectively acted like a bit of a
00:24:09 --> 00:24:11 doona with that raining down and that in the
00:24:11 --> 00:24:14 atmosphere. The fact that it's fallen in the
00:24:14 --> 00:24:17 fossil record above the spherules
00:24:17 --> 00:24:19 means the spherules got to the ground before
00:24:19 --> 00:24:22 the dust got to the ground, effectively. So
00:24:22 --> 00:24:24 the researchers have said, well, what would
00:24:24 --> 00:24:25 happen if you had all this dust, all this
00:24:25 --> 00:24:28 silicate dust in the atmosphere and you had
00:24:28 --> 00:24:30 these ferrules running through, giving off
00:24:30 --> 00:24:33 all this heat? And it's effectively like that
00:24:33 --> 00:24:36 dust in the atmosphere would have acted a bit
00:24:36 --> 00:24:38 like a reflecting, uh, blanket or something
00:24:38 --> 00:24:40 like that. It would have trapped even more of
00:24:40 --> 00:24:42 the heat in the atmosphere and reflected it
00:24:42 --> 00:24:44 back down at the ground. And, um, the
00:24:44 --> 00:24:47 calculations that they've made suggest that
00:24:47 --> 00:24:49 that extra energy, because of the energy
00:24:49 --> 00:24:51 being re radiated back down to the ground,
00:24:51 --> 00:24:54 rather than escaping to space, would have
00:24:54 --> 00:24:56 made things hot enough for grass to catch
00:24:56 --> 00:24:58 fire, for pine cones to catch fire. Not
00:24:58 --> 00:25:01 enough not for an entire tree to burst into
00:25:01 --> 00:25:03 flames, but for all the tinder that was lying
00:25:03 --> 00:25:06 on the ground to be called a flame.
00:25:06 --> 00:25:08 And if that happens, what you do is you
00:25:08 --> 00:25:11 trigger global firestorms. So you
00:25:11 --> 00:25:13 turn a situation and you make it much, much
00:25:13 --> 00:25:16 worse. Now, what should be said
00:25:16 --> 00:25:19 here is this, uh, work is looking at North
00:25:19 --> 00:25:22 America and it strikes me that further
00:25:22 --> 00:25:23 away from the impact site, you probably
00:25:23 --> 00:25:25 wouldn't have got the impact dust. So it
00:25:25 --> 00:25:26 might well be that you actually had a
00:25:26 --> 00:25:29 gradiated kind of level of nastiness from the
00:25:29 --> 00:25:31 impact. So nearby it brutal. And
00:25:32 --> 00:25:33 then you had the tsunamis and stuff washing
00:25:33 --> 00:25:36 out on the far side of the planet. You
00:25:36 --> 00:25:38 probably didn't get the silicate dust, so you
00:25:38 --> 00:25:40 just got the normal level of hellishness
00:25:40 --> 00:25:42 where you didn't set off firestorms, but
00:25:42 --> 00:25:44 things were nasty. But there was probably
00:25:44 --> 00:25:47 this sweet spot like the ultimately bad
00:25:47 --> 00:25:49 porridge in the Cinderella Storey, where
00:25:49 --> 00:25:52 things were ultimately worse, ultimately
00:25:52 --> 00:25:55 as bad as they could be, where the impact
00:25:55 --> 00:25:57 way over the horizon, way in the distance,
00:25:58 --> 00:26:00 was enough to trigger forests to burst into
00:26:00 --> 00:26:02 flame because of igniting the tinder enough
00:26:02 --> 00:26:05 to cook animals alive as they were on the
00:26:05 --> 00:26:08 surface. Uh, really kind of brutal and
00:26:08 --> 00:26:10 remarkably horrific imagery.
00:26:11 --> 00:26:14 But it's fascinating work and m it's another
00:26:14 --> 00:26:16 insight into just how bad impacts like this
00:26:16 --> 00:26:18 could be. It's that whole thing that we're
00:26:18 --> 00:26:21 playing with a detective storey that is 66
00:26:21 --> 00:26:23 million years old and we're trying to piece
00:26:23 --> 00:26:26 together the narrative of what happened and
00:26:26 --> 00:26:27 every bit of information we get like this
00:26:27 --> 00:26:29 just seems to make a more and more horrific
00:26:29 --> 00:26:30 piece picture.
00:26:30 --> 00:26:33 Andrew Dunkley: Yeah, I mean, the original consensus was
00:26:33 --> 00:26:35 the, um, asteroid hit
00:26:36 --> 00:26:39 the planet and, uh, it
00:26:39 --> 00:26:41 created, um, tsunamis that went around the
00:26:41 --> 00:26:43 world, um, three, four times, something like
00:26:43 --> 00:26:46 that. Um, and uh, created
00:26:47 --> 00:26:49 the equivalent of a nuclear winter and
00:26:49 --> 00:26:52 everything died and there was no food and,
00:26:52 --> 00:26:55 uh, the creatures died along with it over a
00:26:55 --> 00:26:58 period of time. But this is suggesting that a
00:26:58 --> 00:27:00 lot of, um, the initial death,
00:27:01 --> 00:27:03 uh, due to these firestorms happened in a few
00:27:03 --> 00:27:06 mere hours. Um, it's a
00:27:06 --> 00:27:07 horrifying thought.
00:27:08 --> 00:27:10 Jonti Horner: It is. And I mean, you start getting to that
00:27:10 --> 00:27:12 kind of philosophical side of thing is does
00:27:12 --> 00:27:14 this make it better or does it make it worse?
00:27:14 --> 00:27:15 You know, if you were there at the time,
00:27:15 --> 00:27:17 would you rather be broiled and baked and
00:27:17 --> 00:27:20 cooked quickly or left to starve slowly in
00:27:20 --> 00:27:23 the cold that followed it? Yeah, I mean it's
00:27:23 --> 00:27:25 all fairly bleak, but it is also that
00:27:25 --> 00:27:27 reminder drawing just a bit like we were
00:27:27 --> 00:27:28 talking about in the previous storey. We are
00:27:28 --> 00:27:30 in the crosshairs. This will happen again.
00:27:30 --> 00:27:32 It's not like the Earth has been hit for the
00:27:32 --> 00:27:35 last time unless we do something about
00:27:35 --> 00:27:38 it. And it's great that we have the capacity
00:27:38 --> 00:27:40 to discover objects further and further
00:27:40 --> 00:27:42 from the Earth with a greater and greater
00:27:42 --> 00:27:44 lead time before they come close to us. It's
00:27:44 --> 00:27:46 great that we're learning the capacity to
00:27:46 --> 00:27:49 deflect them. But it's sometimes hard to
00:27:49 --> 00:27:51 justify to people why people are doing this
00:27:51 --> 00:27:53 kind of research. And it's one of the
00:27:53 --> 00:27:55 arguments we have, for example, against the
00:27:55 --> 00:27:57 satellite megalithic constellations, because
00:27:57 --> 00:27:59 we're finally a spec that can look out at the
00:27:59 --> 00:28:02 cosmos and detect threats. And what we're
00:28:02 --> 00:28:04 doing is we're throwing tinsel in the way and
00:28:04 --> 00:28:04 hiding the view.
00:28:06 --> 00:28:08 Andrew Dunkley: And that is a bit of a worry. Well, it's a
00:28:08 --> 00:28:10 big worry and it's not getting any better. In
00:28:10 --> 00:28:13 fact, it's going to get worse. We'll um,
00:28:13 --> 00:28:15 probably discuss that more in our next
00:28:15 --> 00:28:15 episode.
00:28:15 --> 00:28:18 But, um, I did notice
00:28:18 --> 00:28:21 in sort of looking at this storey that, uh,
00:28:21 --> 00:28:24 some papers or some websites refer to
00:28:24 --> 00:28:26 it as a meteorite impact rather than an
00:28:26 --> 00:28:28 asteroid. Why would they do that?
00:28:28 --> 00:28:31 Jonti Horner: This is interesting with terminology and
00:28:31 --> 00:28:34 I'm less uncomfortable with the idea of
00:28:34 --> 00:28:37 meteorite impact, asteroid impact being
00:28:37 --> 00:28:39 a conflation. The terminology of
00:28:39 --> 00:28:42 objects is a weird one and
00:28:42 --> 00:28:45 astronomers have very specific terminology
00:28:46 --> 00:28:48 that then gets a little bit confused when you
00:28:48 --> 00:28:50 see popular science and you see the news and
00:28:50 --> 00:28:53 all the rest of it when something's floating
00:28:53 --> 00:28:56 around in space nowhere near the Earth,
00:28:56 --> 00:28:59 we refer to it as a meteoroid
00:28:59 --> 00:29:01 or an asteroid or comet, basically.
00:29:02 --> 00:29:04 Um, and we talked about asteroids and comets
00:29:04 --> 00:29:05 earlier on and where the line blurs there.
00:29:07 --> 00:29:09 The typical boundary between
00:29:09 --> 00:29:12 calling a meteoroid and an asteroid is
00:29:12 --> 00:29:15 often taken as being about one metre in size,
00:29:15 --> 00:29:16 but that's just fairly arbitrary.
00:29:18 --> 00:29:21 When something enters the atmosphere and it's
00:29:21 --> 00:29:22 pushing the air in front of it and it's
00:29:22 --> 00:29:25 glowing in the sky, that phenomenon we call
00:29:25 --> 00:29:28 a meteor, if it's really bright, we call it
00:29:28 --> 00:29:30 a fireball. And that boundary is set roughly
00:29:30 --> 00:29:32 as bright as a planet Venus. If we see an
00:29:32 --> 00:29:34 explosion at the end, we call it a bolide.
00:29:34 --> 00:29:36 And that just means exploding fireball,
00:29:36 --> 00:29:39 basically. So meteor, bolide,
00:29:39 --> 00:29:42 fireball are uh, atmospheric phenomena.
00:29:42 --> 00:29:43 You're not actually seeing the thing coming
00:29:43 --> 00:29:46 through the atmosphere, you're seeing the gas
00:29:46 --> 00:29:48 that it's heated up and excited in the
00:29:48 --> 00:29:50 atmosphere. That's what you're seeing as a
00:29:50 --> 00:29:53 glow. When it reaches the ground and hits the
00:29:53 --> 00:29:55 ground, you call it a meteorite. That's the
00:29:55 --> 00:29:58 physical object on the ground or hitting the
00:29:58 --> 00:30:01 ground. Now, whether
00:30:01 --> 00:30:04 you call something like this a meteorite
00:30:04 --> 00:30:05 impact or an asteroid impact, I think it's
00:30:05 --> 00:30:08 probably both. You know, technically the
00:30:08 --> 00:30:11 asteroid hits the ground, um, you
00:30:11 --> 00:30:13 could call it a meteorite. But maybe what you
00:30:13 --> 00:30:15 should do is have that idea in your head of
00:30:15 --> 00:30:17 if it's less than a metre across, you could
00:30:17 --> 00:30:19 call it a meteorite. Bigger than that, you'd
00:30:19 --> 00:30:21 call it an asteroid. I've never seen
00:30:21 --> 00:30:24 clarification on where that
00:30:24 --> 00:30:26 boundary comes because terms are used in
00:30:26 --> 00:30:29 different sensors kind of thing. So for me,
00:30:29 --> 00:30:31 I don't think it's unreasonable to say
00:30:31 --> 00:30:32 meteorite impact here, although you're
00:30:32 --> 00:30:35 probably pushing the size definition.
00:30:36 --> 00:30:38 Call it an asteroid or comet impact is
00:30:38 --> 00:30:40 probably more reasonable. And it might be
00:30:40 --> 00:30:42 that if you dug into the physics of it and
00:30:42 --> 00:30:44 you were to do an IAU resolution a bit like
00:30:44 --> 00:30:47 we did with Pluto, maybe what you do is look
00:30:47 --> 00:30:49 at it in terms of the effect of the
00:30:49 --> 00:30:52 atmosphere on the object coming in. So
00:30:52 --> 00:30:54 things that create fireballs and bolides in
00:30:54 --> 00:30:57 day to day life, the atmosphere is much
00:30:57 --> 00:31:00 bigger in size than the object coming in,
00:31:00 --> 00:31:02 which means wind resistance will eventually
00:31:02 --> 00:31:05 slow it down. So the meteorite that we talked
00:31:05 --> 00:31:06 about a few months ago that landed on
00:31:06 --> 00:31:09 someone's driveway in Canada was travelling
00:31:09 --> 00:31:11 at about the same speed that a rock dropped
00:31:11 --> 00:31:12 out of an aircraft would have done. It was at
00:31:12 --> 00:31:15 terminal velocity. Its speed was
00:31:15 --> 00:31:18 governed by the atmosphere. Whereas with
00:31:18 --> 00:31:20 things that are kilometre scale, the
00:31:20 --> 00:31:22 Atmosphere is essentially not there. It's not
00:31:22 --> 00:31:25 going to slow them down. And so I wonder
00:31:25 --> 00:31:26 whether there is an argument that you could
00:31:26 --> 00:31:29 set up a definition that said if it's
00:31:29 --> 00:31:31 travelling at uh, speed less than
00:31:31 --> 00:31:34 supersonic, you'd call it a meteorite impact.
00:31:34 --> 00:31:36 If it's travelling faster than that, maybe
00:31:36 --> 00:31:38 you'd call it an asteroid impact. But I don't
00:31:38 --> 00:31:40 think that there's any official delineation
00:31:40 --> 00:31:43 like that. That's just kind of how I think
00:31:43 --> 00:31:44 about things in my own head.
00:31:44 --> 00:31:46 Andrew Dunkley: No, I like that that works. Well, well,
00:31:46 --> 00:31:48 that's probably a good way to think about it.
00:31:49 --> 00:31:52 Um, another interesting storey that uh, the
00:31:52 --> 00:31:54 asteroid impact uh, that killed the dinosaurs
00:31:55 --> 00:31:57 was a lot more damaging in the early stages
00:31:57 --> 00:32:00 than we first thought by the look of. But uh,
00:32:00 --> 00:32:02 plenty of, plenty of websites and news
00:32:02 --> 00:32:04 platforms have picked this one up, not
00:32:04 --> 00:32:06 surprisingly. Uh, but you can read
00:32:07 --> 00:32:10 at uh, the Science
00:32:10 --> 00:32:13 Advances, uh, website published in
00:32:13 --> 00:32:15 Science Advances. Uh, this is Space Nuts
00:32:15 --> 00:32:17 Andrew Dunkley here with Johnty Horner.
00:32:20 --> 00:32:22 Jonti Horner: 0G and I feel fine.
00:32:22 --> 00:32:24 Andrew Dunkley: Space Nuts, the storey. Jonty
00:32:25 --> 00:32:27 takes us to Canadia and
00:32:27 --> 00:32:30 this is a storey, uh, about a
00:32:30 --> 00:32:33 Canadian amateur astronomer who
00:32:33 --> 00:32:36 decided to plan a holiday using online maps.
00:32:36 --> 00:32:36 It is.
00:32:36 --> 00:32:38 Jonti Horner: This is lovely. I think we've all done this
00:32:38 --> 00:32:41 to some degree. You planning your holiday,
00:32:41 --> 00:32:42 planning your road trip. I just had a lovely
00:32:42 --> 00:32:45 holiday with the in laws. And you look at uh,
00:32:45 --> 00:32:47 the online maps of your choice that typically
00:32:47 --> 00:32:49 have really nice satellite images of the
00:32:49 --> 00:32:52 places you're um, and you try and figure out
00:32:52 --> 00:32:53 what you're going to see, what you're going
00:32:53 --> 00:32:55 to go there. And to some degree you sat
00:32:55 --> 00:32:57 browsing around thinking, I wonder if I can
00:32:57 --> 00:32:59 see anything unusual, what's it like around
00:32:59 --> 00:33:02 there? And that's what happened
00:33:02 --> 00:33:05 here. We've got this amateur astronomer going
00:33:05 --> 00:33:08 by the name of Joel Lapointe who back in
00:33:08 --> 00:33:10 2024 was planning his hiking and
00:33:10 --> 00:33:13 camping trip. And I think it's in northern
00:33:13 --> 00:33:16 Quebec. It's near a place called Lake Mars.
00:33:17 --> 00:33:20 And he found this unusual looking
00:33:20 --> 00:33:23 feature next to that lake. Looks a bit odd
00:33:23 --> 00:33:26 on the maps on the satellite imaging. Now
00:33:26 --> 00:33:29 there is a university in Canada that has a
00:33:29 --> 00:33:31 website called Impact Earth that allows
00:33:31 --> 00:33:34 people to, as a kind of popular
00:33:34 --> 00:33:36 um, collaborative endeavour for
00:33:36 --> 00:33:39 citizen science is the word I'm looking for
00:33:39 --> 00:33:42 to log things where people think they've
00:33:42 --> 00:33:45 found impact features. So being an
00:33:45 --> 00:33:46 amateur astronomer being aware of this, he
00:33:46 --> 00:33:49 logged it. I think I found a crater. About
00:33:49 --> 00:33:52 a year later, um, the site
00:33:52 --> 00:33:54 as a result of this report was
00:33:55 --> 00:33:57 explored, visited by a planetary geologist
00:33:57 --> 00:34:00 from the university called Gordon Ozinski.
00:34:00 --> 00:34:03 Who went there, took a lot of samples,
00:34:03 --> 00:34:06 explored around and confirmed that
00:34:06 --> 00:34:07 this really is an impact feature. It's an
00:34:07 --> 00:34:09 impact crater about
00:34:10 --> 00:34:12 390 million years old,
00:34:12 --> 00:34:14 so way older than the impact that killed the
00:34:14 --> 00:34:17 dinosaurs. About 25 kilometres
00:34:17 --> 00:34:20 across, which includes a load of
00:34:20 --> 00:34:23 incredibly well preserved features in terms
00:34:23 --> 00:34:26 of glassy hardened volcanic type rocks from
00:34:26 --> 00:34:29 the impact that he himself has said he's
00:34:29 --> 00:34:30 surprised at that well preserved, given how
00:34:30 --> 00:34:33 old it is and how far north this is, how cold
00:34:33 --> 00:34:36 the weather gets in the winter and stuff. Now
00:34:36 --> 00:34:38 this makes it the biggest crater found on
00:34:38 --> 00:34:40 Earth since 2018, when there was a crater
00:34:40 --> 00:34:43 discovered under the Greenland ice sheet. But
00:34:43 --> 00:34:45 the difference is that the one under the
00:34:45 --> 00:34:47 Greenland ice sheet is below a kilometre's
00:34:47 --> 00:34:50 depth of ice. So it isn't like we can get
00:34:50 --> 00:34:51 there and learn much more about it. That's
00:34:51 --> 00:34:53 still quite a mysterious spot.
00:34:54 --> 00:34:56 Whereas this is open and exposed and
00:34:56 --> 00:34:59 accessible, so people are able to go there
00:34:59 --> 00:35:02 and explore it, learn a lot about it. There's
00:35:02 --> 00:35:04 some really nice imagery out there on the
00:35:05 --> 00:35:07 Internet about this. From the maps, images
00:35:07 --> 00:35:10 where it was found to images of
00:35:10 --> 00:35:12 features called shatter cones, which are the
00:35:12 --> 00:35:15 kind of thing created that are very typical
00:35:15 --> 00:35:17 of an impact crater formed under very high
00:35:17 --> 00:35:20 pressure, very high temperature molten rock.
00:35:20 --> 00:35:23 So it is absolutely amazing.
00:35:23 --> 00:35:26 But it's also to me kind of breathtaking that
00:35:26 --> 00:35:29 here is a feature 25 kilometres in diameter
00:35:29 --> 00:35:32 in the middle of a built up, well, not that
00:35:32 --> 00:35:34 built up country, but in the middle of a
00:35:34 --> 00:35:37 country near a famous lake, there is an
00:35:37 --> 00:35:39 impact crater that had never been identified
00:35:39 --> 00:35:42 until now. You know, we're still discovering
00:35:43 --> 00:35:45 kilometres, tens of kilometre scale features
00:35:45 --> 00:35:47 on the Earth. I mean, that's just
00:35:47 --> 00:35:47 astonishing.
00:35:50 --> 00:35:53 Andrew Dunkley: Uh, yeah, it is. And um, I
00:35:53 --> 00:35:56 think we've talked about it in the past that
00:35:56 --> 00:35:58 one of the problems with finding these things
00:35:58 --> 00:36:00 on Earth is the fact that the Earth's kind
00:36:00 --> 00:36:03 of covered up with vegetation and uh,
00:36:03 --> 00:36:06 you know, lots of, um, weather, uh,
00:36:06 --> 00:36:08 activity which has caused erosion and then
00:36:08 --> 00:36:10 we've got earthquakes that have caused
00:36:10 --> 00:36:12 mountain ranges to pop up here and there. And
00:36:12 --> 00:36:15 so a lot of these impact points get uh,
00:36:15 --> 00:36:18 disturbed or are hidden. Not uncommon
00:36:18 --> 00:36:18 now.
00:36:20 --> 00:36:22 Jonti Horner: Absolutely. And I mean 70% of the Earth's
00:36:22 --> 00:36:25 surface is water and you need to be a bigger
00:36:25 --> 00:36:27 impacter than the depth of the ocean to leave
00:36:27 --> 00:36:29 a scar on the ocean floor. So the
00:36:30 --> 00:36:32 history of impacts on the Earth is very much
00:36:32 --> 00:36:35 muddied by all of these different
00:36:35 --> 00:36:37 processes. The Ice Ages have scoured the
00:36:37 --> 00:36:39 surface of the Earth clean. We've got
00:36:39 --> 00:36:41 weathering, we've got forests, the Earth's
00:36:41 --> 00:36:43 surface is actually an incredibly dynamic
00:36:43 --> 00:36:46 place compared to the Moon. If you look at
00:36:46 --> 00:36:48 the Moon, there are many craters of this kind
00:36:48 --> 00:36:50 of size. And one of the things that is
00:36:50 --> 00:36:51 actually discussed in the articles online
00:36:51 --> 00:36:54 about this is whether this could be a venue
00:36:54 --> 00:36:56 for people to learn more in preparation for
00:36:56 --> 00:36:58 visits to the Moon where we can go to craters
00:36:58 --> 00:37:00 or vice versa. Whether we could learn more
00:37:00 --> 00:37:02 about craters like this by going to the ones
00:37:02 --> 00:37:04 on the Moon that are the same size but are
00:37:04 --> 00:37:06 pristine because we're at a similar
00:37:06 --> 00:37:08 location with similar targets in the shooting
00:37:08 --> 00:37:11 gallery. But on the Earth everything gets
00:37:11 --> 00:37:13 worn away fairly effectively, whereas on the
00:37:13 --> 00:37:16 Moon it stays pretty pristine until something
00:37:16 --> 00:37:18 else hits it and weathers it away. The only
00:37:18 --> 00:37:19 real way you're going to weather lunar
00:37:19 --> 00:37:22 craters, um, with a few exceptions, is
00:37:22 --> 00:37:24 by other things hitting them and muddying the
00:37:24 --> 00:37:27 water. There is going to be a lot more to
00:37:27 --> 00:37:30 learn about this. It is still relatively new
00:37:30 --> 00:37:32 news. The geologists involved
00:37:33 --> 00:37:35 won't be going there year round because it
00:37:35 --> 00:37:36 gets really, really cold and really
00:37:36 --> 00:37:38 unpleasant in the winter. So there'll be
00:37:38 --> 00:37:40 summer expeditions going there, trying to
00:37:40 --> 00:37:42 learn more about it, getting more and more
00:37:42 --> 00:37:44 samples of it. Because we don't know many
00:37:44 --> 00:37:46 craters that are that old on the Earth.
00:37:46 --> 00:37:49 Andrew Dunkley: No, this is 390 million
00:37:49 --> 00:37:51 years. That's a long time back, isn't
00:37:51 --> 00:37:54 it? That's over 300 million years beyond the
00:37:54 --> 00:37:55 dinosaur impact.
00:37:56 --> 00:37:59 Jonti Horner: Absolutely pretty impressive. It's far from
00:37:59 --> 00:38:01 the oldest crater on the Earth, but I would
00:38:01 --> 00:38:04 argue that we know far more younger craters
00:38:04 --> 00:38:06 than this than. We know older craters than
00:38:06 --> 00:38:06 this.
00:38:06 --> 00:38:09 Andrew Dunkley: Yeah. Didn't they recently say they found
00:38:09 --> 00:38:12 the oldest one in Western Australia? Was it?
00:38:12 --> 00:38:15 Jonti Horner: Yeah. Then I think that was a little bit
00:38:15 --> 00:38:16 controversial, but there was a lot of talk
00:38:16 --> 00:38:18 about shattercons with that one as well.
00:38:18 --> 00:38:20 Andrew Dunkley: Yes, there was, Yeah, I remember that.
00:38:21 --> 00:38:23 Jonti Horner: You know, these are, uh, we're finding
00:38:23 --> 00:38:25 craters more and more and they tell us about
00:38:25 --> 00:38:27 the history of the Earth and the heritage of
00:38:27 --> 00:38:30 it. With the really old craters, there's even
00:38:30 --> 00:38:33 some arguments that the, ah, largest impacts
00:38:33 --> 00:38:35 that happened very early on in the Earth's
00:38:35 --> 00:38:38 history were actually the seeds of the
00:38:38 --> 00:38:40 continents to some degree. There was some
00:38:40 --> 00:38:43 amazing work. This is probably actually best
00:38:43 --> 00:38:45 part of a decade ago now. But there was great
00:38:45 --> 00:38:47 work by Craig o' Neill and his team that were
00:38:47 --> 00:38:50 looking at trying to model the initiation of
00:38:50 --> 00:38:51 plate tectonics on the Earth. So how did
00:38:51 --> 00:38:53 plate tectonics get going? And, um, these
00:38:53 --> 00:38:55 incredibly talented geophysicists here in
00:38:55 --> 00:38:58 Australia were running models where
00:38:58 --> 00:39:00 you start the Earth with no plate tectonics,
00:39:00 --> 00:39:02 looking at the interior, looking at how hot
00:39:02 --> 00:39:04 it was back then. And if you started the
00:39:04 --> 00:39:06 Earth without plate tectonics, plate
00:39:06 --> 00:39:08 tectonics didn't happen. And uh, what they
00:39:08 --> 00:39:11 thought could be the smoking gun was that you
00:39:11 --> 00:39:14 had impacts that caused a big impulse of
00:39:14 --> 00:39:16 energy and motion in the mantle
00:39:17 --> 00:39:19 that triggered a downwelling which would then
00:39:19 --> 00:39:21 trigger an upwelling and you could get impact
00:39:21 --> 00:39:24 induced plate tectonics which would then
00:39:24 --> 00:39:26 cause these things to maybe even give you the
00:39:26 --> 00:39:28 seeds of the continents of the earliest
00:39:28 --> 00:39:31 continents. And that's an
00:39:31 --> 00:39:32 awesome storey. The videos that they made of
00:39:32 --> 00:39:35 their simulations were fabulous. And
00:39:35 --> 00:39:37 um, yeah, it's amazing what more there is
00:39:37 --> 00:39:38 still to learn, I guess.
00:39:38 --> 00:39:41 Andrew Dunkley: Yeah, absolutely true. And this is another
00:39:41 --> 00:39:43 storey that's been picked up by Orlin Sundry.
00:39:44 --> 00:39:46 Uh, so, um, yeah, you shouldn't have any
00:39:46 --> 00:39:48 trouble finding it if you do, um, a search
00:39:48 --> 00:39:51 for the Canadian amateur astronomer who was
00:39:51 --> 00:39:53 planning his holiday. And uh, the storey will
00:39:53 --> 00:39:56 pop up just about everywhere. Space.com, the
00:39:56 --> 00:39:58 Smithsonian magazine, et cetera, et cetera.
00:39:58 --> 00:40:01 Uh, and uh, by, by now,
00:40:01 --> 00:40:04 when you hear this episode or very close to
00:40:04 --> 00:40:07 this point in time, uh, the team
00:40:07 --> 00:40:09 that uh, made the discovery will be
00:40:09 --> 00:40:11 presenting their work at the 88th Annual
00:40:11 --> 00:40:14 Meeting of the Meteor. Uh,
00:40:14 --> 00:40:17 meteoritis. I can't say
00:40:17 --> 00:40:20 it, uh, Meteorocital
00:40:20 --> 00:40:22 Society in Germany, I think. That's right. I
00:40:22 --> 00:40:25 don't know. Anyway, yeah, look it up. It's a
00:40:25 --> 00:40:25 great yarn.
00:40:25 --> 00:40:28 Uh, we've had a very rocky programme today.
00:40:29 --> 00:40:32 Um, Jonty, it's been fascinating the
00:40:32 --> 00:40:34 way those storeys all dovetailed into each
00:40:34 --> 00:40:36 other. Uh, and we're at the end. Thank you
00:40:36 --> 00:40:38 very much. Nice to see you again.
00:40:39 --> 00:40:40 Jonti Horner: Uh, it's good to be back. Thank you for
00:40:40 --> 00:40:41 having me and hope
00:40:41 --> 00:40:43 Andrew Dunkley: Fred Watson's enjoying his jaunt
00:40:44 --> 00:40:45 chasing a, uh, solar eclipse.
00:40:45 --> 00:40:48 Jonti Horner: Yes, yes, it's a hard life but somebody's got
00:40:48 --> 00:40:48 to do it.
00:40:48 --> 00:40:50 Andrew Dunkley: Absolutely true. I'm waiting for one to come
00:40:50 --> 00:40:52 to me. I only have to wait two more years.
00:40:52 --> 00:40:53 Jonti Horner: Two more years.
00:40:54 --> 00:40:54 Andrew Dunkley: Thanks.
00:40:54 --> 00:40:56 Jonti Horner: And it'll be cloudy. You know it's going to
00:40:56 --> 00:40:56 be cloudy.
00:40:56 --> 00:40:57 Andrew Dunkley: Oh yeah, it's probably going to be raining
00:40:57 --> 00:41:00 training and I'm m giving up a game of golf
00:41:00 --> 00:41:02 for it too. All right, thanks Jonty. We'll
00:41:02 --> 00:41:05 see you soon. Yeah, It's a pleasure,
00:41:05 --> 00:41:06 Professor Jonty Horner, professor of
00:41:06 --> 00:41:08 Astrophysics at the University of Southern
00:41:08 --> 00:41:11 Queensland. Don't forget, uh, to visit us
00:41:11 --> 00:41:13 online while uh, you are, ah, waiting for the
00:41:13 --> 00:41:14 next episode,
00:41:14 --> 00:41:16 spacenutspodcast.com
00:41:17 --> 00:41:18 and have a look around while you're there.
00:41:18 --> 00:41:21 Visit the shop, etc etc and thanks to Huw in
00:41:21 --> 00:41:23 the studio couldn't be with us today. Um, put
00:41:23 --> 00:41:25 his home address in Google Maps. We haven't
00:41:25 --> 00:41:27 seen him since. And from me, Andrew Dunkley.
00:41:27 --> 00:41:29 Thanks for your company. We'll see you on the
00:41:29 --> 00:41:31 next next episode of Space Nuts. Bye. Bye.
00:41:33 --> 00:41:35 Jonti Horner: You've been listening to the Space Nuts
00:41:35 --> 00:41:38 podcast, available at
00:41:38 --> 00:41:40 Apple Podcasts, Spotify,
00:41:40 --> 00:41:43 iHeartRadio or your favourite podcast
00:41:43 --> 00:41:44 player. You can also stream on
00:41:44 --> 00:41:46 demand@bytes.com M.
00:41:46 --> 00:41:48 Andrew Dunkley: This has been another quality podcast
00:41:48 --> 00:41:51 production from bytes.com.