00:00:00 --> 00:00:02 Stuart Gary: This is space Time Series 28 Episode
00:00:02 --> 00:00:04 102 for broadcast on 25
00:00:04 --> 00:00:07 August 2025. Coming up on space
00:00:08 --> 00:00:10 time, planet Earth dodges two asteroid
00:00:10 --> 00:00:13 near misses within days of each other. A new
00:00:13 --> 00:00:16 moon discovered orbiting around the planet Uranus
00:00:17 --> 00:00:19 and dancing dwarf galaxies may help predict the
00:00:19 --> 00:00:22 Milky Way's ultimate fate. All that and more
00:00:22 --> 00:00:24 coming up on, uh, Space Time.
00:00:26 --> 00:00:28 Voice Over Guy: Welcome to Space Time with Stuart
00:00:28 --> 00:00:29 Gary
00:00:45 --> 00:00:48 Stuart Gary: Planet Earth has just dodged two asteroid near misses
00:00:48 --> 00:00:51 within days of each other, both swooping past the Earth
00:00:51 --> 00:00:53 lower than the orbits of many satellites.
00:00:53 --> 00:00:56 Asteroid 2025 PF2 sped
00:00:56 --> 00:00:59 past the Earth at an altitude of just 22
00:00:59 --> 00:01:02 kilometers, traveling at around 13 kilometers per
00:01:02 --> 00:01:05 second. Estimated to be somewhere between 2 and
00:01:05 --> 00:01:08 6 meters in size, the space rock was flying in
00:01:08 --> 00:01:10 the constellation Aquila ah as it passed. Then
00:01:10 --> 00:01:13 there's asteroid 2025 PU1. It missed
00:01:13 --> 00:01:16 the Earth by just 29 kilometers, traveling at
00:01:16 --> 00:01:19 around 10 kilometers per second. It's
00:01:19 --> 00:01:22 estimated to have been somewhere between 2 and 3 meters in
00:01:22 --> 00:01:24 diameter and is currently in the direction of the constellation
00:01:24 --> 00:01:27 Pegasus. The frightening thing about
00:01:27 --> 00:01:29 2025 PU1 is that it was only
00:01:29 --> 00:01:32 observed 4 hours after it met its closest approach.
00:01:33 --> 00:01:36 It belongs to the Apollo class of near Earth asteroids
00:01:36 --> 00:01:39 and will make its next close approach to the Earth on, um, April
00:01:39 --> 00:01:42 3, 2036. It was the 10th
00:01:42 --> 00:01:45 closest asteroid flyby of Earth in just 12 months,
00:01:45 --> 00:01:48 the 85th known flyby of the planet within
00:01:48 --> 00:01:50 one lunar distance since the start of the year and the
00:01:50 --> 00:01:53 third so far this month. This is
00:01:53 --> 00:01:56 space time. Still to come, a new
00:01:56 --> 00:01:59 moon discovered orbiting the planet Uranus and
00:01:59 --> 00:02:02 dancing dwarf galaxies could help predict the ultimate
00:02:02 --> 00:02:05 fate of our own Milky Way. All that and more
00:02:05 --> 00:02:07 still to come on space time.
00:02:23 --> 00:02:25 Astronomers m have discovered another moon orbiting around the
00:02:25 --> 00:02:28 ice giant planet Uranus. The new
00:02:28 --> 00:02:30 observations were made using NASA's Webb Space
00:02:30 --> 00:02:33 Telescope. The previously unknown moon brings
00:02:33 --> 00:02:36 the total number of satellites orbiting Uranus to 26.
00:02:37 --> 00:02:40 The object was detected in a series of ten 40
00:02:40 --> 00:02:43 minute long exposure images captured by Webb's near
00:02:43 --> 00:02:45 infrared Camera. One of the study's authors,
00:02:45 --> 00:02:48 Maryam Al Mutamid from the Southwest Research
00:02:48 --> 00:02:51 Institute in Boulder, Colorado, says it's a small
00:02:51 --> 00:02:54 but significant discovery, which is something that even
00:02:54 --> 00:02:56 NASA's Voyager 2 spacecraft didn't see during its
00:02:56 --> 00:02:59 flyby of Uranus 40 years ago. The
00:02:59 --> 00:03:02 newly discovered moon is estimated to be around 10 kilometers
00:03:02 --> 00:03:05 in diameter. That's assuming it has a similar reflectivity
00:03:05 --> 00:03:08 or albedo to Uranus. Other small satellites
00:03:08 --> 00:03:11 it was its tiny size, which likely rendered it
00:03:11 --> 00:03:14 invisible to Voyager 2 and earlier telescope
00:03:14 --> 00:03:17 observations. No, uh, other planet has as many
00:03:17 --> 00:03:20 small inner moons as Uranus. And their complex
00:03:20 --> 00:03:22 interrelationships with the planet's rings hint at a
00:03:22 --> 00:03:25 chaotic history that blurs the boundary between what
00:03:25 --> 00:03:27 a ring system is and what's really a
00:03:27 --> 00:03:30 constellation of moons. Also, this New
00:03:30 --> 00:03:33 Moon discovery is a lot smaller and fainter than the smallest
00:03:33 --> 00:03:36 of the previously known inner moons, making it likely
00:03:36 --> 00:03:39 that even more complexity remains to be discovered in the
00:03:39 --> 00:03:42 system. The New moon is the 14th member
00:03:42 --> 00:03:45 of the intricate constellation of small moons orbiting
00:03:45 --> 00:03:47 inwards of the largest moons, Miranda, Ariel,
00:03:47 --> 00:03:50 Umberal, Titania, and Oberon, all of which
00:03:50 --> 00:03:53 were named after characters from Shakespeare and Alexander
00:03:53 --> 00:03:56 Pope. It's located about 56
00:03:56 --> 00:03:59 kilometers from the center of Uranus. And it's orbiting the ice
00:03:59 --> 00:04:01 giant's equatorial plane between the orbits of
00:04:01 --> 00:04:04 Ophelia, which is just outside the planet's main ring system.
00:04:04 --> 00:04:07 And Bianca. The authors believe its nearly
00:04:07 --> 00:04:10 circular orbit suggests that it may have formed near its
00:04:10 --> 00:04:12 current location. As for a name for the
00:04:12 --> 00:04:15 newly found moon, well, that'll wait until one is approved by the
00:04:15 --> 00:04:18 International Astronomical Union, the leading authority in
00:04:18 --> 00:04:21 assigning official names and designations to astronomical
00:04:21 --> 00:04:24 objects. The discovery continues to build upon a
00:04:24 --> 00:04:27 legacy of missions like Voyager 2, which flew past
00:04:27 --> 00:04:30 Uranus back in January 1986, giving
00:04:30 --> 00:04:33 humanity its first close up look at this mysterious
00:04:33 --> 00:04:36 world. Now, nearly four decades later, the
00:04:36 --> 00:04:38 Webb Space Telescope is pushing that frontier
00:04:39 --> 00:04:42 even further. This is space time.
00:04:42 --> 00:04:45 Still to come, a new study trying to determine the
00:04:45 --> 00:04:48 ultimate fate of our Milky Way galaxy. And later
00:04:48 --> 00:04:51 in the science report, the first almost
00:04:51 --> 00:04:53 100% effective prevention drug for HIV
00:04:53 --> 00:04:56 AIDS. All that and more still to come,
00:04:56 --> 00:04:57 um, on space time.
00:05:02 --> 00:05:05 Okay, let's take a break from our show for a word from our sponsor, uh,
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00:06:58 --> 00:07:01 A new study is trying to determine the ultimate
00:07:01 --> 00:07:04 fate of our Milky Way galaxy as it hurtles towards
00:07:04 --> 00:07:07 a merger with our big galactic neighbor, M M31
00:07:07 --> 00:07:09 Andromeda. As the two galaxies come
00:07:09 --> 00:07:12 closer together, the gravitational tidal forces
00:07:12 --> 00:07:15 interacting between them will cause both to undergo
00:07:15 --> 00:07:17 massive changes. Now, a new study
00:07:17 --> 00:07:20 reported in the Journal of the Monthly Notices of the Royal
00:07:20 --> 00:07:23 Astronomical Society suggests that the cosmic dance
00:07:23 --> 00:07:25 of small, smaller satellite galaxies orbiting around the two
00:07:25 --> 00:07:28 giants will also play a significant role in
00:07:28 --> 00:07:31 that ultimate cosmic collision. One of the
00:07:31 --> 00:07:34 study's authors, Sarah Sweet from the University of Queensland,
00:07:34 --> 00:07:37 says the Milky Way will merge with Andromeda and with their
00:07:37 --> 00:07:40 respective smaller dwarf galaxies in the next two and a half
00:07:40 --> 00:07:43 to seven billion years. And while there's been a
00:07:43 --> 00:07:45 lot of research into what's happening in our local galactic group,
00:07:45 --> 00:07:48 astronomers really don't know how typical that will be.
00:07:49 --> 00:07:52 So to better understand how representative such a galactic collision
00:07:52 --> 00:07:55 will be, Sweet and colleagues studied NGC
00:07:55 --> 00:07:57 5713 and NGC
00:07:57 --> 00:08:00 5719, which are two very similar
00:08:00 --> 00:08:03 spiral galaxies which are about 3 billion years ahead
00:08:03 --> 00:08:05 of where the Milky Way and Andromeda now are in their
00:08:05 --> 00:08:08 merging. The authors are showing that these
00:08:08 --> 00:08:10 galaxies are combining as if they were dancing with
00:08:10 --> 00:08:13 closely located dwarf satellites rotating around them.
00:08:14 --> 00:08:17 It may provide our clearest look yet at how
00:08:17 --> 00:08:20 structures like the Milky Way satellite Galaxy System
00:08:21 --> 00:08:23 and how over the next few billion years, it'll evolve.
00:08:24 --> 00:08:27 Understanding our galaxy's likely future helps
00:08:27 --> 00:08:29 astronomers refine models of galactic evolution,
00:08:30 --> 00:08:32 models of dark matter, and models of the cosmic
00:08:32 --> 00:08:35 structure of the universe. Sweet says.
00:08:35 --> 00:08:38 We're all part of a much larger cosmic story,
00:08:38 --> 00:08:40 one that unfolds over billions of years,
00:08:41 --> 00:08:44 involving dances of galaxies and the shaping of
00:08:44 --> 00:08:47 the universe itself. She says. By comparing our
00:08:47 --> 00:08:49 Local Galaxy Group with other systems like it,
00:08:49 --> 00:08:52 astronomers can determine whether the Milky Way and Andromeda
00:08:53 --> 00:08:55 Group are a poster child for this sort of event or a
00:08:55 --> 00:08:58 cosmic outlier. Until astronomers know
00:08:58 --> 00:09:01 this, their ability to generalize findings from the Local
00:09:01 --> 00:09:04 Group of galaxies to understand galaxy evolution in a
00:09:04 --> 00:09:06 broader cosmological context remains hampered.
00:09:06 --> 00:09:09 For example, there's a persisting tension between the
00:09:09 --> 00:09:12 Local Galaxy Group observations and the world's most
00:09:12 --> 00:09:15 sophisticated cosmological computer models, such
00:09:15 --> 00:09:18 as the observed placement of dwarf galaxies preferentially
00:09:18 --> 00:09:20 in satellite planes around their hosts.
00:09:21 --> 00:09:24 And these observations therefore suggest that scientists will need
00:09:24 --> 00:09:27 to, uh, overhaul their current computer simulations.
00:09:27 --> 00:09:30 Sweet wants to know the Milky Way will begin its own
00:09:30 --> 00:09:32 dance with Andromeda, with the smaller dwarf galaxies
00:09:32 --> 00:09:33 rotating around them.
00:09:34 --> 00:09:37 Dr Sarah Sweet : Well, just like in our own Local Group, that's what
00:09:37 --> 00:09:39 you've been describing. Our, uh, Milky Way, Andromeda, our
00:09:39 --> 00:09:42 satellite galaxies, our dwarfs, including the Large and Small
00:09:42 --> 00:09:45 Magellanic Cloud, Sagittarius as well, and
00:09:45 --> 00:09:48 dozens of other satellites. We've been studying other
00:09:48 --> 00:09:51 systems that are quite like our Local Group. One in particular
00:09:51 --> 00:09:54 is this pair of gal, NGC 5713 and
00:09:54 --> 00:09:57 NGC 5719. They're quite like our
00:09:57 --> 00:10:00 Milky Way and Andromeda in that they're both massive spiral
00:10:00 --> 00:10:03 galaxies and they're approaching each other just like our
00:10:03 --> 00:10:06 Milky Way and Andromeda are approaching as well. And they
00:10:06 --> 00:10:08 both have associated dwarf galaxies with them. What's
00:10:08 --> 00:10:11 unusual about this system is that their dwarf
00:10:11 --> 00:10:14 galaxies are rotating around the center of mass
00:10:14 --> 00:10:17 of both of the galaxies rather than being
00:10:17 --> 00:10:19 associated with either one. They're not in a
00:10:19 --> 00:10:22 random cloud, but they're actually showing this rotation
00:10:23 --> 00:10:26 and what we think this system is quite
00:10:26 --> 00:10:28 like, what our Local Group will be like. In about 2 to
00:10:28 --> 00:10:30 3 billion years.
00:10:30 --> 00:10:32 Stuart Gary: Some degree of organization will come together. The
00:10:32 --> 00:10:35 gravitational tidal forces won't just simply cause
00:10:35 --> 00:10:38 things to plunge through each other. They'll arrange them in a, in
00:10:38 --> 00:10:39 a different way.
00:10:39 --> 00:10:42 Dr Sarah Sweet : Yes, that's right, because as you've described, there's, there's a
00:10:42 --> 00:10:45 lot going on just around our, ah, Milky Way galaxy that
00:10:45 --> 00:10:48 our dwarfs are interacting. They're also interacting
00:10:48 --> 00:10:50 with our Milky Way galaxy. And on a
00:10:50 --> 00:10:53 slightly larger scale, we see These dwarfs rotating in a
00:10:53 --> 00:10:56 disk around their Milky Way. We also see dwarf galaxies is
00:10:56 --> 00:10:59 rotating in a disk around Andromeda. And
00:10:59 --> 00:11:02 the same thing we see happening around a lot of other galaxies as
00:11:02 --> 00:11:05 well. But what we expect is that as
00:11:05 --> 00:11:08 our Milky Way and Andromeda continue to approach each
00:11:08 --> 00:11:11 other, the dwarfs won't be just orbiting each massive
00:11:11 --> 00:11:13 galaxy, they'll actually be orbiting the whole system.
00:11:13 --> 00:11:16 And we think this is a way that these flat
00:11:16 --> 00:11:19 rotating disks of dwarf satellite galaxies can
00:11:19 --> 00:11:20 actually form.
00:11:20 --> 00:11:22 Stuart Gary: Are, uh, globular clusters the cause of merged
00:11:22 --> 00:11:25 dwarf galaxies, or are they individual
00:11:26 --> 00:11:28 nurseries of stars that are formed together and
00:11:28 --> 00:11:29 stayed together?
00:11:29 --> 00:11:32 Dr Sarah Sweet : Yeah, well, there are differences between dwarf
00:11:32 --> 00:11:35 galaxies and globular clusters. Globular clusters
00:11:35 --> 00:11:38 tend to have slightly or sometimes much
00:11:38 --> 00:11:40 more simple stellar populations. So they've had,
00:11:40 --> 00:11:42 usually had fewer generations.
00:11:43 --> 00:11:45 Stuart Gary: Of star formation, similar composition, and close,
00:11:46 --> 00:11:47 very close, gravitationally.
00:11:47 --> 00:11:50 Dr Sarah Sweet : Yes, that's right. So we think just a single epoch of
00:11:50 --> 00:11:53 star formation in globular clusters. Some are larger, like
00:11:53 --> 00:11:55 Omega Cen, um, you might have heard of
00:11:55 --> 00:11:58 47P. These are, um, a bit larger, like
00:11:58 --> 00:12:01 they're the largest ones. And they have had probably a
00:12:01 --> 00:12:04 few generations of star formations and stellar evolution. But
00:12:04 --> 00:12:07 dwarf galaxies tend to have a lot more of this. And
00:12:07 --> 00:12:10 so even if you're seeing just the cores, you still see
00:12:10 --> 00:12:13 a, uh, larger spread in their stellar population
00:12:13 --> 00:12:16 characteristics. Also. Another difference is that when
00:12:16 --> 00:12:19 there's a cores of dwarf galaxies, they still have a
00:12:19 --> 00:12:21 massive intermediate, massive or black
00:12:21 --> 00:12:24 hole at the, at the center, whereas globular
00:12:24 --> 00:12:27 clusters don't. And we also have a halo of dark
00:12:27 --> 00:12:29 matter still surrounding these stripped dwarf galax.
00:12:30 --> 00:12:33 There's a few ways that we can distinguish them.
00:12:33 --> 00:12:35 Stuart Gary: Uh, you just mentioned the key phrase halos of
00:12:35 --> 00:12:38 dark matter. These provide what we consider
00:12:38 --> 00:12:41 the scaffold of the universe, don't they?
00:12:41 --> 00:12:43 Dr Sarah Sweet : Yes, yes, that's right. Uh,
00:12:44 --> 00:12:47 in fact, our simulations trace these building blocks.
00:12:47 --> 00:12:49 We have simulations of dark matter halos, and they
00:12:49 --> 00:12:52 come together, they gravitationally interact and form
00:12:52 --> 00:12:55 larger and larger halos, and so too the
00:12:55 --> 00:12:58 galaxies inside them. So in our, uh, cosmological
00:12:58 --> 00:13:01 simulations, we inject the baryons or so, you
00:13:01 --> 00:13:03 know, the uh, luminous matter into these dark matter
00:13:03 --> 00:13:06 halos and retrace the evolution of the galaxies and their
00:13:06 --> 00:13:08 halos over cosmic time.
00:13:08 --> 00:13:10 Stuart Gary: And as you look at these computer models, these
00:13:10 --> 00:13:13 simulations, how do they compare with what you see in the real
00:13:13 --> 00:13:13 world?
00:13:14 --> 00:13:17 Dr Sarah Sweet : M. Well, for the most part, uh, very good they
00:13:17 --> 00:13:19 are. Our cutting edge simulations
00:13:19 --> 00:13:22 describe a lot about what we see really quite well.
00:13:23 --> 00:13:25 One key difference and something that
00:13:25 --> 00:13:28 I'm and my colleagues are interested in is that
00:13:28 --> 00:13:31 it extremely rare to see a flat rotating
00:13:31 --> 00:13:34 disk or satellite around a galaxy. But
00:13:34 --> 00:13:37 we see this, as I've mentioned, around our Milky Way,
00:13:37 --> 00:13:40 around Andromeda, and half a dozen or so other,
00:13:40 --> 00:13:43 um, systems nearby to us that we can study in great
00:13:43 --> 00:13:45 detail. So it's a bit of a puzzle to know
00:13:45 --> 00:13:48 just how this happens when our, uh, simulations don't
00:13:48 --> 00:13:51 capture it. But they do so well on, um, so many other
00:13:51 --> 00:13:53 characteristics. And so that's why what we've found
00:13:53 --> 00:13:56 with this rotating system is quite interesting, because we think
00:13:56 --> 00:13:58 that's one way that these can form.
00:13:58 --> 00:14:01 Stuart Gary: As you've carried out your obs and you looked at
00:14:01 --> 00:14:04 5713 and 5719,
00:14:04 --> 00:14:05 what are you seeing there?
00:14:05 --> 00:14:08 Dr Sarah Sweet : Well, what we're seeing is that the
00:14:08 --> 00:14:11 dwarf galaxies around these two massive
00:14:11 --> 00:14:14 spirals are, uh, in this sort of like this cosmic dance
00:14:14 --> 00:14:17 around these other two. So they've been falling, they've been
00:14:17 --> 00:14:20 approaching the center of mass, but trailing
00:14:20 --> 00:14:22 behind their massive, their host galaxy.
00:14:22 --> 00:14:25 So whereas they might have been isotropically
00:14:25 --> 00:14:28 distributed so randomly around the two
00:14:28 --> 00:14:31 massive galaxies as they were more separated as they're
00:14:31 --> 00:14:34 approaching each other, trailing along behind.
00:14:34 --> 00:14:37 And because the conservation of angular momentum as
00:14:37 --> 00:14:39 these two galaxies approach, it's like they're, they're pulling their
00:14:39 --> 00:14:42 arms in as like a figure skater, spinning
00:14:42 --> 00:14:45 faster. And so these dwarf galaxies, as they're approaching
00:14:45 --> 00:14:48 too, they feel this gravitational pull, and that's why they're
00:14:48 --> 00:14:51 coming in, in this rotating structure, we think.
00:14:51 --> 00:14:54 And, um. Yeah, so you get these. Yeah, they
00:14:54 --> 00:14:56 get, they do get into line. It's not a disc shape yet.
00:14:56 --> 00:14:59 It's still puffy. And it's like they're in these two wedge shapes,
00:14:59 --> 00:15:02 one either side. When you look at an image, you
00:15:02 --> 00:15:05 see these two massive galaxies in the middle, and
00:15:05 --> 00:15:08 all the galaxies on the left wedge are there
00:15:08 --> 00:15:11 approaching us. All the galaxies on the right hand wedge, they're
00:15:11 --> 00:15:13 moving away from us. So it's this really dramatic
00:15:13 --> 00:15:15 rotation that we can see.
00:15:15 --> 00:15:18 Stuart Gary: It sounds like as the merger continues
00:15:18 --> 00:15:21 over the next few billion years, these two galaxies won't
00:15:21 --> 00:15:23 be forming an elliptical galaxy, but probably a bigger
00:15:23 --> 00:15:25 spiral. Am I getting that right?
00:15:25 --> 00:15:28 Dr Sarah Sweet : Yeah, it's possible. It does depend,
00:15:28 --> 00:15:31 um, just on the angle of inclination
00:15:31 --> 00:15:34 that's the biggest one. It's a little bit hard to tell from
00:15:34 --> 00:15:37 the projected angle that we see, but one we can see edge on and
00:15:37 --> 00:15:40 one we can see face on, and we can actually see
00:15:40 --> 00:15:43 in the one that's edge on a little bit of a warp in the disk
00:15:43 --> 00:15:46 already. And in fact, the hydrogen gas, the neutral
00:15:46 --> 00:15:48 hydrogen that surrounds these galaxies, it's actually already
00:15:48 --> 00:15:51 forming a bridge between them. They are already interacting,
00:15:51 --> 00:15:54 uh, even though they don't look much like they are
00:15:54 --> 00:15:56 in the optical sense already.
00:15:56 --> 00:15:59 Stuart Gary: Now, when we look at our own Milky Way galaxy, not all that
00:15:59 --> 00:16:02 long ago, we discovered a warp in the disk of our galaxy as
00:16:02 --> 00:16:02 well.
00:16:02 --> 00:16:05 Dr Sarah Sweet : Yes. And that could be also because, you know, we have this neighbour,
00:16:05 --> 00:16:08 Andromeda, we are approaching each other, but that
00:16:08 --> 00:16:11 interaction is a lot. We've got another.
00:16:11 --> 00:16:14 Yes, it is a lot more subtle and a lot earlier on as well. So
00:16:14 --> 00:16:17 we've got, like I said, 2 or 3 billion years before we get
00:16:17 --> 00:16:20 as close and as interacting as this pair
00:16:20 --> 00:16:23 NGC 5713 and 19 is, they're.
00:16:23 --> 00:16:26 Stuart Gary: A lot more at advanced stage now when galaxies
00:16:26 --> 00:16:29 collide. It sounds spectacular, but it's not
00:16:29 --> 00:16:32 like two billiard balls hitting each other on the table,
00:16:32 --> 00:16:32 is it?
00:16:32 --> 00:16:35 Dr Sarah Sweet : That's right. There's a lot of empty space between the
00:16:35 --> 00:16:37 stars. When our Milky Way and
00:16:37 --> 00:16:40 Andromeda merge, the biggest difference
00:16:40 --> 00:16:43 for people on Earth, if Earth was still to be
00:16:43 --> 00:16:46 around then, um, then would be that we would just
00:16:46 --> 00:16:49 see the night sky becoming filled with stars.
00:16:49 --> 00:16:52 We see Andromeda approaching and there's. But
00:16:52 --> 00:16:55 the, the stars in Andromeda would be, uh, moving past the
00:16:55 --> 00:16:58 stars in our galaxy. And so, yeah, we'd see
00:16:58 --> 00:17:01 a much more full night guy.
00:17:01 --> 00:17:03 Stuart Gary: We see those computer simulations of the two
00:17:03 --> 00:17:06 galaxies merging. Do you think they're fairly representative
00:17:06 --> 00:17:09 or is your data showing it's going to be a little different to that?
00:17:09 --> 00:17:12 Dr Sarah Sweet : Well, that's one thing that we want to find out. We know a
00:17:12 --> 00:17:14 lot about our Milky Way and Andromeda and
00:17:14 --> 00:17:17 our dwarf galaxies. Because they're so close to us.
00:17:17 --> 00:17:20 We can resolve individual stars and we
00:17:20 --> 00:17:23 studied them in such great detail, but we don't know how
00:17:23 --> 00:17:26 well we can apply this knowledge to the rest of the
00:17:26 --> 00:17:29 universe in particular because we don't see all of the
00:17:29 --> 00:17:31 characteristics in our simulations. So, uh, something
00:17:32 --> 00:17:34 maybe, like you said, maybe it is just by random jump that we see these
00:17:34 --> 00:17:37 planes of satellites, for example. So that's what we're doing
00:17:37 --> 00:17:40 with this Local Group analog study is looking at
00:17:40 --> 00:17:43 these other systems that are as close to
00:17:43 --> 00:17:46 our Local Group as we can find and
00:17:46 --> 00:17:49 looking at them in, um, as much detail as
00:17:49 --> 00:17:52 we can and working out how far down in detail
00:17:52 --> 00:17:55 we need to go before we start seeing differences to our
00:17:55 --> 00:17:58 Milky Way and Andromeda and therefore
00:17:58 --> 00:18:01 what the limit of that extrapol might be. This pair
00:18:01 --> 00:18:04 of galaxies is one of our
00:18:04 --> 00:18:07 samples from our survey delegate, which is
00:18:07 --> 00:18:10 so called because the dwarf galaxies, ah, are delegates of
00:18:10 --> 00:18:13 their environment, so that they represent their host
00:18:13 --> 00:18:16 galaxies and their neighbours. We have handpicked
00:18:16 --> 00:18:19 these various local group analogues and
00:18:19 --> 00:18:21 this one in particular, my colleague at
00:18:21 --> 00:18:24 anu, Helmet, Jurgen, was looking in detail
00:18:24 --> 00:18:27 at this existing imaging of this system
00:18:27 --> 00:18:30 and he was looking at the velocity field, the
00:18:30 --> 00:18:32 velocity field of the hydrogen between the
00:18:32 --> 00:18:35 galaxies, piecing together existing observations that
00:18:35 --> 00:18:38 hadn't been combined before. And he had some deep
00:18:38 --> 00:18:40 imaging as well, looked at the
00:18:41 --> 00:18:44 velocities from existing catalogues of
00:18:44 --> 00:18:46 the different dwarf galaxies around
00:18:46 --> 00:18:49 the system and discovered that there was this
00:18:49 --> 00:18:52 striking difference between the dwarf galaxies on the
00:18:52 --> 00:18:55 left side of the figure and on the right side of the figure. And
00:18:55 --> 00:18:58 that's where he got the clue that the dwarf galaxy galaxies were
00:18:58 --> 00:19:01 actually rotating in this coherent
00:19:01 --> 00:19:03 motion around the two massive hosts.
00:19:03 --> 00:19:06 Stuart Gary: That's Dr. Sarah Sweet from the University of
00:19:06 --> 00:19:09 Queensland. And this is space,
00:19:09 --> 00:19:09 time
00:19:25 --> 00:19:26 and time.
00:19:26 --> 00:19:28 Now to take a brief look at some of the other stories making news in Science
00:19:28 --> 00:19:30 this week with a science report.
00:19:31 --> 00:19:34 Researchers in the United States believe they may have finally
00:19:34 --> 00:19:37 developed the first almost 100% effective prevention
00:19:37 --> 00:19:40 drug for HIV AIDS. America's
00:19:40 --> 00:19:42 food and Drug Administration has now approved the Lena
00:19:42 --> 00:19:45 Kappavir vaccine which is being sold under the brand name
00:19:45 --> 00:19:48 Yestoogo. It belongs to a class of
00:19:48 --> 00:19:51 antiretroviral medications known as capsid
00:19:51 --> 00:19:53 inhibitors. See, in the HIV type 1
00:19:53 --> 00:19:56 virus, the capsid is the protein shell that houses
00:19:56 --> 00:19:59 and protects the viral genetic material and it's crucial
00:19:59 --> 00:20:02 for transporting the virus into a host cell.
00:20:02 --> 00:20:05 Once inside the host cell, the capsids shed
00:20:05 --> 00:20:07 and the virus begins copying itself.
00:20:07 --> 00:20:10 Lenacapavir stops that from happening.
00:20:10 --> 00:20:13 In 2022, it was approved under the brand name
00:20:13 --> 00:20:16 Sunlinka to treat HIV in those already infected.
00:20:16 --> 00:20:19 But a long acting prevention medication has been much
00:20:19 --> 00:20:22 more difficult to realize. Last year,
00:20:22 --> 00:20:25 Lencapavir was named as the breakthrough invention of the year
00:20:25 --> 00:20:27 in the journal Science. The drug is now
00:20:27 --> 00:20:30 available across the European Union and the United States and
00:20:30 --> 00:20:32 it's awaiting regulatory approval in Australia,
00:20:33 --> 00:20:35 Brazil, Canada, South Africa, Switzerland,
00:20:35 --> 00:20:38 Argentina, Mexico and Peru. The
00:20:38 --> 00:20:40 human immunodeficiency virus
00:20:41 --> 00:20:44 attacks the immune system, causing Acquired Immune
00:20:44 --> 00:20:46 Deficiency Syndrome, or aids, which allows opportunistic
00:20:46 --> 00:20:49 diseases to normally easily combated by the body to
00:20:49 --> 00:20:52 take hold and eventually kill the patient.
00:20:52 --> 00:20:55 The World Health Organization says that since first being
00:20:55 --> 00:20:58 identified back in 1981, AIDS has
00:20:58 --> 00:21:00 killed over 43 million people globally and
00:21:00 --> 00:21:03 infected up to 113 million. With
00:21:03 --> 00:21:05 1.3 million new infections annually.
00:21:06 --> 00:21:09 HIV is transmitted through body fluids. Right
00:21:09 --> 00:21:12 now, there's no cure, although it can be controlled
00:21:12 --> 00:21:15 using a combination of complex drug cocktails. Australopithecus
00:21:16 --> 00:21:18 paleoanthropologists have discovered a new species of
00:21:18 --> 00:21:21 Australopithecus hominid, the earliest known member of
00:21:21 --> 00:21:24 the human family. The new fossil finds,
00:21:24 --> 00:21:27 reported in the journal Nature date back to between 2.6
00:21:27 --> 00:21:30 and 2.8 million years and coexisted with
00:21:30 --> 00:21:33 Australopithecus afarensis at the same place in
00:21:33 --> 00:21:35 Ethiopia at the same time. The
00:21:35 --> 00:21:38 oldest evidence of Australopithecus afarensis dates
00:21:38 --> 00:21:41 back some 2.95 million years years. The
00:21:41 --> 00:21:44 new Lady Garou Australopithecus species are based on
00:21:44 --> 00:21:47 just 13 teeth discoveries and demonstrate how
00:21:47 --> 00:21:50 human evolution was not linear, but a bushy
00:21:50 --> 00:21:53 tree with many branches going extinct. The
00:21:53 --> 00:21:56 authors are now examining the newly discovered species tooth
00:21:56 --> 00:21:59 enamel to try and find out what they can about what these
00:21:59 --> 00:22:01 species were eating. A
00:22:01 --> 00:22:04 new study has shown that some seabirds prefer to
00:22:04 --> 00:22:07 defecate in the air, so much so they'll actually
00:22:07 --> 00:22:10 take flight just to take a damp. Scientists
00:22:10 --> 00:22:12 strapped cameras to the bellies of 15 streaked
00:22:12 --> 00:22:15 shearwaters, migratory birds that travel from Japan as
00:22:15 --> 00:22:18 far as Australia. And they found that all but one
00:22:18 --> 00:22:21 of the 195 video bombardments were
00:22:21 --> 00:22:23 airborne. A report in the journal Current
00:22:23 --> 00:22:26 Biology claims in flight evacuations, for
00:22:26 --> 00:22:29 want of a better term, may have benefits outweighing the
00:22:29 --> 00:22:32 efforts to take off from the water, like avoiding germs,
00:22:32 --> 00:22:35 protecting the birds, delicate bits from seawater and a
00:22:35 --> 00:22:38 comfier position than simply floating. The
00:22:38 --> 00:22:41 authors say the findings could also help studies in how seabird
00:22:41 --> 00:22:44 excrement contributes to ocean ecosystems and
00:22:44 --> 00:22:47 whether bird flu can be transmitted between birds out at
00:22:47 --> 00:22:50 sea. Then again, as far as the bird's concerned,
00:22:50 --> 00:22:52 it may just be easier to target people from the air.
00:22:54 --> 00:22:57 A bunch of academics from the National Autonomous University
00:22:57 --> 00:23:00 of Mexico are giving credibility to a UFO
00:23:00 --> 00:23:03 report from Columbia. The UFO was first
00:23:03 --> 00:23:05 spotted flying over the town of Buga, reportedly
00:23:05 --> 00:23:08 zigzagging through the sky in a way that witnesses claim
00:23:08 --> 00:23:11 defies the movement of conventional aircraft.
00:23:11 --> 00:23:14 The ball shaped object was allegedly later seen sitting on
00:23:14 --> 00:23:17 the ground, where it was quickly recovered and taken away for
00:23:17 --> 00:23:19 testing. That led to claims there was a strong m
00:23:19 --> 00:23:22 decaying ionized field coming from the sphere.
00:23:22 --> 00:23:25 Others claimed it could be radiating anions.
00:23:25 --> 00:23:28 These are negatively charged ions that have gained an
00:23:28 --> 00:23:31 electron or another negatively charged subatomic particle in
00:23:31 --> 00:23:34 order to fill their outer shells. Those behind the
00:23:34 --> 00:23:37 story claim that since the investigation began, this
00:23:37 --> 00:23:40 UFO is now five times heavier than what it was when it
00:23:40 --> 00:23:42 landed and they say that proves that it's
00:23:42 --> 00:23:45 manipulating gravity to make itself lighter in order
00:23:45 --> 00:23:48 to fly. Tim Mendham, um, from Australian Skeptics
00:23:48 --> 00:23:51 says it's worth pointing out the guy pushing the story has
00:23:51 --> 00:23:53 a long history of making elaborate fake space
00:23:53 --> 00:23:55 alien claims.
00:23:55 --> 00:23:57 Tim Mendham: This is a sphere that was supposedly floating in the
00:23:57 --> 00:24:00 sky, performing sort of weird movements and things and then
00:24:00 --> 00:24:03 found on the ground. Originally seen in Colombia,
00:24:03 --> 00:24:06 South America, but there's now researchers in
00:24:06 --> 00:24:08 Mexico having a look at it from a place called the National
00:24:08 --> 00:24:11 Autonomous University of Mexico. People there
00:24:11 --> 00:24:13 promoting some sort of invisible energy emanating
00:24:13 --> 00:24:16 from this machine that when it landed, uh, it was
00:24:16 --> 00:24:19 a burnt out area or something. They're saying it sucked all the
00:24:19 --> 00:24:22 water out of the grass and the soil and that there's all sorts
00:24:22 --> 00:24:25 of strange things going on emanating from it. There's engravings all the way
00:24:25 --> 00:24:28 around it and the engravings look pretty sloppy quite frankly. And they do.
00:24:28 --> 00:24:31 They're hardly the sort of work of advanced species
00:24:31 --> 00:24:32 sending these things across.
00:24:33 --> 00:24:35 Stuart Gary: How do we know we wouldn't know what an alien
00:24:35 --> 00:24:37 script looks like? Like would we or would we?
00:24:37 --> 00:24:40 Tim Mendham: No, we don't of course. No, there's not a lot of it around. But anything they
00:24:40 --> 00:24:43 can't understand naturally becomes alien 51 anyway.
00:24:43 --> 00:24:46 Yeah, I mean the, it was suggested that this is an art project
00:24:46 --> 00:24:49 and in any case there's no actual link between a thing that was
00:24:49 --> 00:24:52 seen in the sky, whatever it was, you know, unidentified. I'm not going to say flying
00:24:52 --> 00:24:55 saucer or alien technology, just something that was seen in
00:24:55 --> 00:24:58 the sky and then this was found that there's no necessarily
00:24:58 --> 00:25:01 connection apart from correlation that these two things are
00:25:01 --> 00:25:04 associated with each other. A thing in the sky, ball found on the
00:25:04 --> 00:25:07 ground, bit bigger than a soccer ball with these strange sort of little
00:25:07 --> 00:25:08 carvings on it.
00:25:08 --> 00:25:09 Stuart Gary: They're very small people.
00:25:09 --> 00:25:12 Tim Mendham: I don't know if it was a craft with people inside. There's supposed to be a lot of
00:25:12 --> 00:25:14 wires and things inside. I don't know how X raying this.
00:25:14 --> 00:25:17 Stuart Gary: Thing or something but advanced civilization is still using
00:25:17 --> 00:25:18 copper wires, are they?
00:25:20 --> 00:25:23 Tim Mendham: Um, this craft apparently bumped up against some power lines and
00:25:23 --> 00:25:26 that took all the energy out of it. So not a particularly good craft for
00:25:26 --> 00:25:29 bringing across the great depths of space. But it's just one
00:25:29 --> 00:25:32 of those things that you think is just one of those silly things that
00:25:32 --> 00:25:34 people are getting carried away with. And there's some academics within this
00:25:34 --> 00:25:37 university who are endorsing it. And it's also being
00:25:37 --> 00:25:40 heavily promoted by a quote UFO
00:25:40 --> 00:25:43 researcher who is known for faking and
00:25:43 --> 00:25:46 promoting fake products you know, mummified bodies that
00:25:46 --> 00:25:49 turn out not to be sort of, uh, mummified alien bodies at all,
00:25:49 --> 00:25:51 or all sorts of evidence of UFO sightings that have been
00:25:51 --> 00:25:54 seriously debunked. So one of the main proponents of this thing is someone
00:25:54 --> 00:25:57 he really had trouble trusting or certainly
00:25:57 --> 00:26:00 believing. And others are some academics who are making some really
00:26:00 --> 00:26:03 quite outlandish statements. The things that sort of just don't comply with
00:26:03 --> 00:26:06 the laws of physics at all. But they're using these as the
00:26:06 --> 00:26:09 explanation of why this is a real, um, alien technology.
00:26:09 --> 00:26:12 Doesn't look particularly impressive from my point of view, especially the
00:26:12 --> 00:26:15 carvings, the engravings on the side of it. They just look sort of
00:26:15 --> 00:26:15 amateurish.
00:26:15 --> 00:26:18 Stuart Gary: That's Tim Mendham from Australian Skeptics.
00:26:34 --> 00:26:37 And that's the show for now. Space Time is
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