Sources & Further Reading ● Space.com — SpaceX launches satellite repair drone with 10-foot robotic arms to Earth orbit ● NASASpaceflight.com — Falcon 9 to launch MRV-1 robotic servicing spacecraft for Northrop Grumman ● Northrop Grumman SpaceLogistics — Mission Robotic Vehicle and Mission Extension Pod fact sheets ● Scientific American — A SpaceX rocket is about to crash into the moon; scientists will be watching ● Phys.org — When a SpaceX rocket crashes into the moon, scientists will be watching (arXiv preprint) ● Project Pluto (Bill Gray) — Upper stage impacting the moon on 2026 August 5 ● Stanford University — Researchers uncover evidence for sibling supernovas (Michailidis et al., Nature Communications) ● Reuters — Scientists spot evidence of two huge companion stars that blew up ● Space.com — Galaxy cluster's magnetic field reconstructed for 1st time with record-breaking astronomy map (Botteon et al., INAF, A&A) ● Southwest Research Institute — SwRI-led research connects asteroid collision to impact showers 800 million years ago ● The Planetary Science Journal — Bottke, Vokrouhlický, Dykhuis & Zellner, "An 800 Myr-old Impact Shower on the Terrestrial Planets from the Breakup of the Eulalia Parent Body" ● EarthSky — Delta Aquariid meteor shower: all you need to know in 2026 ● NASA Science — Total Solar Eclipse on August 12, 2026 (path, partial visibility and safety guidance) ● BBC Sky at Night Magazine — August 12, 2026 solar eclipse: USA and Canada guide Connect ● Website: astronomydaily.io ● Socials: @AstroDailyPod ● Part of the Bitesz.com Podcast Network
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00:00:00 --> 00:00:02 Anna: Somewhere above your head right now, about
00:00:02 --> 00:00:05 36 km up,
00:00:05 --> 00:00:08 there is a graveyard shift going on.
00:00:08 --> 00:00:11 Hundreds of satellites still working,
00:00:11 --> 00:00:14 still useful, and slowly running out of
00:00:14 --> 00:00:14 fuel.
00:00:15 --> 00:00:17 Avery: And as of last night, there is finally a
00:00:17 --> 00:00:18 mechanic on the way.
00:00:19 --> 00:00:22 Anna: Good evening and welcome to Astronomy Daily.
00:00:22 --> 00:00:23 I'm Anna.
00:00:23 --> 00:00:26 Avery: And I'm Avery. Coming up, a spacecraft
00:00:26 --> 00:00:28 with arms launches on a mission to keep other
00:00:28 --> 00:00:31 spacecraft alive. A rocket stage is two
00:00:31 --> 00:00:33 weeks out from hitting the moon and
00:00:33 --> 00:00:35 astronomers have just put out a call to arms
00:00:35 --> 00:00:36 about it.
00:00:36 --> 00:00:39 Anna: We've got two stars that were born together,
00:00:39 --> 00:00:42 lived together and then died in sequence,
00:00:42 --> 00:00:44 leaving behind the first pair of
00:00:44 --> 00:00:47 supernova remnants ever traced back to
00:00:47 --> 00:00:49 a single binary.
00:00:49 --> 00:00:52 Avery: The first complete magnetic map of a galaxy
00:00:52 --> 00:00:54 cluster, an asteroid breakup that may have
00:00:54 --> 00:00:57 bombarded three worlds and helped freeze our
00:00:57 --> 00:00:57 own.
00:00:58 --> 00:01:00 Anna: And a sky watching window that is closing
00:01:00 --> 00:01:02 faster than you'd like.
00:01:02 --> 00:01:03 Avery: Let's get into it.
00:01:04 --> 00:01:07 Anna: So Avery, here's a problem that has quietly
00:01:07 --> 00:01:09 bothered the satellite industry for about
00:01:09 --> 00:01:12 60 years. You build a satellite, you
00:01:12 --> 00:01:15 spend hundreds of millions of dollars on it.
00:01:15 --> 00:01:17 You put it in geostationary orbit
00:01:17 --> 00:01:19 35
00:01:19 --> 00:01:22 km up where it hovers
00:01:22 --> 00:01:25 over the same patch of ground forever. And
00:01:25 --> 00:01:28 it works beautifully for 15 years
00:01:28 --> 00:01:30 and then it runs out of fuel.
00:01:30 --> 00:01:33 Avery: And um, that's, uh, it. The hardware is fine.
00:01:33 --> 00:01:36 Anna: The hardware is often perfectly fine. The
00:01:36 --> 00:01:38 cameras work, the transponders work, the
00:01:38 --> 00:01:41 solar panels work. But without propellant,
00:01:41 --> 00:01:44 it can't hold its position. So it drifts
00:01:44 --> 00:01:47 and it becomes junk. You throw away a
00:01:47 --> 00:01:50 working satellite because the tank is empty.
00:01:51 --> 00:01:53 Avery: That is a spectacularly wasteful way to run
00:01:53 --> 00:01:53 an industry.
00:01:54 --> 00:01:57 Anna: It is. And last night, Northrop
00:01:57 --> 00:01:59 Grumman launched the most serious attempt yet
00:01:59 --> 00:02:02 to fix it. At 05:15 in the
00:02:02 --> 00:02:05 evening Eastern Time on Tuesday 21st
00:02:05 --> 00:02:08 July, the Falcon 9 lifted
00:02:08 --> 00:02:11 off from Space Launch Complex 40 at
00:02:11 --> 00:02:14 Cape Canaveral carrying the Mission Robotic
00:02:14 --> 00:02:17 Vehicle plus three Mission Extension
00:02:17 --> 00:02:17 pods.
00:02:18 --> 00:02:20 Avery: Mission robotic vehicle. What does it
00:02:20 --> 00:02:21 actually look like?
00:02:21 --> 00:02:24 Anna: Picture a satellite bus with two
00:02:24 --> 00:02:27 arms, two robotic arms, each
00:02:27 --> 00:02:28 about 3 meters long,
00:02:29 --> 00:02:32 built by the United States Naval Research
00:02:32 --> 00:02:35 Laboratory and supplied through DARPA's
00:02:35 --> 00:02:37 Robotic Servicing of Geostationary
00:02:37 --> 00:02:38 Satellite program.
00:02:39 --> 00:02:42 Avery: So this is a genuinely dexterous machine, not
00:02:42 --> 00:02:43 just the tug that bolt on.
00:02:44 --> 00:02:47 Anna: That's the distinction that matters. The MRV
00:02:47 --> 00:02:50 can inspect, it can relocate, it can
00:02:50 --> 00:02:52 repair, it can upgrade. And its
00:02:52 --> 00:02:55 headline job on this mission is to pick up
00:02:55 --> 00:02:58 those three mission extension pods and
00:02:58 --> 00:03:00 install them on client satellites that are
00:03:00 --> 00:03:02 running low on propellant.
00:03:02 --> 00:03:05 Avery: So the pods are the actual fuel solution.
00:03:06 --> 00:03:08 Anna: Think of them as jetpacks. Each pod
00:03:08 --> 00:03:11 clamps onto a satellite and takes over orbit
00:03:11 --> 00:03:14 control and momentum management. Using
00:03:14 --> 00:03:17 electric propulsion, each one can handle a
00:03:17 --> 00:03:19 satellite of about 2kg.
00:03:19 --> 00:03:22 That's a typical big geostationary bird
00:03:22 --> 00:03:25 and give it up to eight more years of life.
00:03:26 --> 00:03:28 Avery: Eight years on a satellite that was
00:03:28 --> 00:03:29 otherwise finished.
00:03:30 --> 00:03:33 Anna: Eight years. And the MRV M itself
00:03:33 --> 00:03:35 carries something called a ah, Passive
00:03:35 --> 00:03:37 Refueling Interface, which is the first
00:03:37 --> 00:03:40 refueling interface approved by the US
00:03:40 --> 00:03:43 Space Force. So the servicer is
00:03:43 --> 00:03:45 itself designed to be refueled later.
00:03:46 --> 00:03:48 Avery: Now, Northrub have done a version of this
00:03:48 --> 00:03:49 before, haven't they?
00:03:49 --> 00:03:52 Anna: They have, and this is why they're the ones
00:03:52 --> 00:03:55 doing it. Mission extension vehicle 1
00:03:55 --> 00:03:58 launched in October 2019, the
00:03:58 --> 00:04:00 first commercial satellite servicing
00:04:00 --> 00:04:03 spacecraft ever. And four months later, it
00:04:03 --> 00:04:05 docked with communications satellite
00:04:05 --> 00:04:08 Intelsat 901 in geostationary
00:04:08 --> 00:04:11 orbit. MEV 2 followed in
00:04:11 --> 00:04:12 August 2020.
00:04:12 --> 00:04:14 Avery: So what's different this time?
00:04:14 --> 00:04:17 Anna: Those earlier vehicles were one to one.
00:04:17 --> 00:04:20 One servicer went to one satellite, docked
00:04:20 --> 00:04:22 with it, and stayed there doing the work
00:04:22 --> 00:04:25 itself. The MRV is one to
00:04:25 --> 00:04:28 many. It carries pods, installs them,
00:04:28 --> 00:04:31 and moves on. It's the difference between a
00:04:31 --> 00:04:33 tow truck that has to stay attached to your
00:04:33 --> 00:04:36 car forever and. And a mechanic who fits a
00:04:36 --> 00:04:39 new part and drives off to the next job.
00:04:39 --> 00:04:40 Avery: That scales.
00:04:40 --> 00:04:43 Anna: That scales. And there's a nice detail on
00:04:43 --> 00:04:46 the launch itself. The Falcon 9 booster
00:04:46 --> 00:04:49 B1069 was flying its
00:04:49 --> 00:04:51 32nd mission and it was
00:04:51 --> 00:04:53 deliberately expended. No landing.
00:04:54 --> 00:04:56 Avery: Why give up a booster with 31 flights on it?
00:04:57 --> 00:04:59 Anna: Because geostationary transfer orbit is
00:04:59 --> 00:05:02 demanding. Getting that much mass that
00:05:02 --> 00:05:05 high needed every bit of performance the
00:05:05 --> 00:05:07 rocket had, and there wasn't propellant left
00:05:07 --> 00:05:10 for a landing burn. SpaceX made the trade.
00:05:10 --> 00:05:12 Avery: So when does the actual servicing start?
00:05:13 --> 00:05:15 Anna: Not for a while. The MRV and the three
00:05:15 --> 00:05:18 pods each separate and then climb to
00:05:18 --> 00:05:21 geostationary orbit under their own
00:05:21 --> 00:05:23 solar electric propulsion. And that
00:05:23 --> 00:05:26 climb takes up to a year. Servicing
00:05:26 --> 00:05:28 operations are expected to begin in
00:05:28 --> 00:05:31 2027. After the initial checkouts,
00:05:31 --> 00:05:34 the RSGS program gets handed over to
00:05:34 --> 00:05:35 the US Space Force.
00:05:36 --> 00:05:38 Avery: A year of just going up slowly
00:05:38 --> 00:05:40 and efficiently.
00:05:40 --> 00:05:43 Anna: Electric propulsion is patient. And at the
00:05:43 --> 00:05:45 end of it, for the first time, there's a
00:05:45 --> 00:05:48 repair capability parked permanently in
00:05:48 --> 00:05:51 the most valuable orbital real estate we
00:05:51 --> 00:05:51 have.
00:05:51 --> 00:05:53 Avery: Right from a machine built to preserve
00:05:53 --> 00:05:56 spacecraft to a spacecraft that is about to
00:05:56 --> 00:05:58 be very thoroughly destroyed.
00:05:58 --> 00:06:00 Anna: This is one we've been tracking.
00:06:00 --> 00:06:02 Avery: It is, and I want to be upfront about that.
00:06:02 --> 00:06:05 We covered this back in June in episode
00:06:05 --> 00:06:08 125. But there is a genuine reason
00:06:08 --> 00:06:10 to come back to it, because the science
00:06:10 --> 00:06:12 community has just done something about it.
00:06:12 --> 00:06:15 The short version for anyone joining us
00:06:15 --> 00:06:17 since. In January 2025,
00:06:17 --> 00:06:20 a Falcon 9 launched two commercial
00:06:20 --> 00:06:23 lunar landers, Firefly's Blue Ghost
00:06:23 --> 00:06:26 and ispace's Hakuto R mission
00:06:26 --> 00:06:29 2. It did its job, but the upper
00:06:29 --> 00:06:31 stage, cataloged as
00:06:31 --> 00:06:34 2025010 d
00:06:34 --> 00:06:37 never came home. Instead of burning up in our
00:06:37 --> 00:06:40 atmosphere, it ended up in a long looping
00:06:40 --> 00:06:43 orbit through the Earth Moon system. And
00:06:43 --> 00:06:44 somebody noticed.
00:06:44 --> 00:06:47 Anna: The independent astronomer Bill Gray, who
00:06:47 --> 00:06:49 runs Project Pluto and tracks this sort of
00:06:49 --> 00:06:52 high orbit debris. His software flagged an
00:06:52 --> 00:06:55 impact on the 5th of August. This year
00:06:55 --> 00:06:57 that stage hits the Moon.
00:06:58 --> 00:07:01 Avery: So what's new? Three things. First, a
00:07:01 --> 00:07:04 new preprint has just gone up on Arxiv and it
00:07:04 --> 00:07:07 is signed by 23 astronomers. It is
00:07:07 --> 00:07:09 essentially a call to arms. They're asking
00:07:09 --> 00:07:12 the scientific community, professional and
00:07:12 --> 00:07:15 amateur, to point everything they've got at
00:07:15 --> 00:07:16 the moon on the 5th of August.
00:07:17 --> 00:07:19 Anna: Because this is a rare thing, because
00:07:19 --> 00:07:22 Avery: we almost never get this. We get natural
00:07:22 --> 00:07:24 impacts on the Moon all the time, but we
00:07:24 --> 00:07:27 don't know when they're coming here. We know
00:07:27 --> 00:07:30 the object, we know its mass, we know its
00:07:30 --> 00:07:32 structure, we know its velocity and we know
00:07:32 --> 00:07:35 the time to within about a second. That is an
00:07:35 --> 00:07:38 artificial impact experiment we didn't have
00:07:38 --> 00:07:39 to pay to set up.
00:07:39 --> 00:07:42 Anna: And the timing has been tightened, hasn't it?
00:07:42 --> 00:07:44 Avery: That's a second u, uh, thing. Gray's latest
00:07:44 --> 00:07:47 published calculation, dated the 17th of July
00:07:47 --> 00:07:50 puts the impact at 6, 34 and
00:07:50 --> 00:07:53 32 seconds UTC. Earlier coverage
00:07:53 --> 00:07:55 back in May was quoting 644.
00:07:56 --> 00:07:58 So if you've got the old number written down,
00:07:58 --> 00:08:01 update it am the third. The third is
00:08:01 --> 00:08:04 the actual physics prediction and this is the
00:08:04 --> 00:08:07 part I find genuinely interesting. The paper
00:08:07 --> 00:08:10 models what happens on contact. This thing
00:08:10 --> 00:08:12 is roughly 12 meters long and about
00:08:12 --> 00:08:15 4 kilograms and crucially, it's
00:08:15 --> 00:08:17 hollow. It's a tank. So the
00:08:17 --> 00:08:20 prediction is that it crushes rather than
00:08:20 --> 00:08:22 punching deep like a can
00:08:22 --> 00:08:23 Anna: rather than a bullet.
00:08:23 --> 00:08:26 Avery: Exactly like a can. And the result of
00:08:26 --> 00:08:29 that is a relatively shallow crater. They're
00:08:29 --> 00:08:32 estimating 20 to 30 meters across, but a
00:08:32 --> 00:08:34 a very large ejecta plume,
00:08:34 --> 00:08:37 kilometers of debris thrown up off the
00:08:37 --> 00:08:37 surface.
00:08:38 --> 00:08:39 Anna: So the plume might be the visible part.
00:08:40 --> 00:08:42 Avery: That's the hope, and it's a subtle bit of
00:08:42 --> 00:08:45 reasoning. The impact site is near the crater
00:08:45 --> 00:08:48 Einstein right on the moon's western limb,
00:08:48 --> 00:08:50 about the 10 o' clock position on the disk.
00:08:50 --> 00:08:53 As you look at it now, that's awkward because
00:08:53 --> 00:08:56 it's on the sunlit part of the surface and no
00:08:56 --> 00:08:58 impact Flash, artificial or natural,
00:08:59 --> 00:09:01 has ever been recorded on the lit face of the
00:09:01 --> 00:09:01 Moon.
00:09:02 --> 00:09:05 Anna: The glare defeats you, but being on the limb
00:09:05 --> 00:09:05 helps.
00:09:05 --> 00:09:08 Avery: Being on the limb might save it, because
00:09:08 --> 00:09:10 rocks thrown up from a site that close to the
00:09:10 --> 00:09:13 edge rise off the Moon entirely. And
00:09:13 --> 00:09:14 once they're off the limb, they're
00:09:14 --> 00:09:17 silhouetted against black sky, catching
00:09:17 --> 00:09:20 sunlight. So you might not see the flash, but
00:09:20 --> 00:09:21 you might see the plume.
00:09:21 --> 00:09:22 Anna: Who else is watching?
00:09:23 --> 00:09:25 Avery: NASA's Lunar Reconnaissance Orbiter will
00:09:25 --> 00:09:28 image the site before and after, which gives
00:09:28 --> 00:09:30 a clean comparison. And South Korea's
00:09:30 --> 00:09:32 Pathfinder Lunar Orbiter is going to attempt
00:09:32 --> 00:09:35 to observe as well. There's precedent for the
00:09:35 --> 00:09:38 afterimage too. When a Chinese rocket stage
00:09:38 --> 00:09:40 hit the far side in 2022, LRO
00:09:41 --> 00:09:43 found the site and it had made not one
00:09:43 --> 00:09:44 crater, but two.
00:09:44 --> 00:09:46 Anna: And there's a longer term payoff to
00:09:46 --> 00:09:49 Avery: all this, and this is why the paper matters.
00:09:49 --> 00:09:52 Beyond the spectacle, they want to test a
00:09:52 --> 00:09:54 method for pinpointing exactly where an
00:09:54 --> 00:09:56 object strikes the Moon using the
00:09:56 --> 00:09:58 observations. If you can nail that down
00:09:58 --> 00:10:01 against a known impact, you've validated a
00:10:01 --> 00:10:03 technique. And that feeds directly into
00:10:03 --> 00:10:05 planning seismic experiments on the lunar
00:10:05 --> 00:10:07 surface for future missions.
00:10:07 --> 00:10:10 Anna: Now the practical question, who actually gets
00:10:10 --> 00:10:11 to see this?
00:10:11 --> 00:10:13 Avery: And, um, this is where our North American
00:10:13 --> 00:10:16 listeners want to pay attention, because this
00:10:16 --> 00:10:17 one is squarely yours.
00:10:18 --> 00:10:20 6:34 UTC on the 5th of August
00:10:20 --> 00:10:23 is 29 minutes past 2 in the morning, Eastern
00:10:23 --> 00:10:25 Time. 1:34 Central,
00:10:26 --> 00:10:29 12:34 Mountain. And on the west coast
00:10:29 --> 00:10:31 it's still the night before. 11:34 in the
00:10:31 --> 00:10:33 evening on the 4th,
00:10:33 --> 00:10:35 Anna: middle of the night, but the Moon is well up.
00:10:36 --> 00:10:38 Avery: The Moon is well placed across the continent,
00:10:38 --> 00:10:40 and the paper specifically identifies
00:10:40 --> 00:10:43 observers in the Americas as the ideal group.
00:10:43 --> 00:10:45 If you have a telescope and you've ever
00:10:45 --> 00:10:48 wanted to contribute to something real, this
00:10:48 --> 00:10:51 is the night they are explicitly asking
00:10:51 --> 00:10:52 amateurs to take part.
00:10:52 --> 00:10:55 Anna: And for those of us further around the globe,
00:10:55 --> 00:10:56 less kind.
00:10:56 --> 00:10:58 Avery: And I'll be straight about it. For us In
00:10:58 --> 00:11:01 Australia, that's 4:34 in the afternoon,
00:11:01 --> 00:11:04 broad daylight, New Zealand early evening,
00:11:04 --> 00:11:07 no good either. The UK and Europe get half
00:11:07 --> 00:11:09 past seven in the morning, which is also
00:11:09 --> 00:11:11 daylight. So the live event belongs to the
00:11:11 --> 00:11:14 Anna: Americas, but the aftermath belongs to
00:11:14 --> 00:11:14 everyone.
00:11:15 --> 00:11:17 Avery: The aftermath belongs to everyone. The
00:11:17 --> 00:11:20 LRO before and after imagery, the crater
00:11:20 --> 00:11:23 measurements, the analysis of how well the
00:11:23 --> 00:11:25 predictions held up, and frankly, the
00:11:25 --> 00:11:27 question sitting underneath all of this is
00:11:27 --> 00:11:29 global. We are about to start putting people
00:11:29 --> 00:11:32 back on the Moon and we are currently hitting
00:11:32 --> 00:11:35 it with our own rubbish by accident, without
00:11:35 --> 00:11:35 warning.
00:11:36 --> 00:11:38 Anna: Alright, Avery, moving on to our next story.
00:11:39 --> 00:11:42 More than Half of all stars are in multiple
00:11:42 --> 00:11:45 systems, two or more suns orbiting each
00:11:45 --> 00:11:48 other. And for the really massive stars, the
00:11:48 --> 00:11:51 ones destined to explode, that fraction is
00:11:51 --> 00:11:52 even higher.
00:11:53 --> 00:11:55 Avery: So most supernovae should have had a sibling.
00:11:55 --> 00:11:58 Anna: That is exactly the implication. And yet,
00:11:58 --> 00:12:01 until this week, astronomers had never found
00:12:01 --> 00:12:03 a single case where both stars in a binary
00:12:03 --> 00:12:06 exploded and both left behind remnants we
00:12:06 --> 00:12:07 can still see
00:12:08 --> 00:12:09 Avery: not one out of how many.
00:12:10 --> 00:12:13 Anna: We've cataloged around 300 supernova
00:12:13 --> 00:12:15 remnants in our galaxy. Not one confirmed
00:12:15 --> 00:12:18 sibling pair. And the reason is a bit
00:12:18 --> 00:12:20 embarrassing, actually. One of them was
00:12:20 --> 00:12:22 probably sitting in plain sight the whole
00:12:22 --> 00:12:22 time.
00:12:23 --> 00:12:23 Avery: Go on.
00:12:24 --> 00:12:25 Anna: The Jellyfish Nebula
00:12:25 --> 00:12:28 IC443 in the
00:12:28 --> 00:12:30 constellation Gemini, about 6
00:12:30 --> 00:12:33 light years away. It is one of the best
00:12:33 --> 00:12:36 studied supernova remnants in the sky and
00:12:36 --> 00:12:38 one of the brightest gamma ray sources of its
00:12:38 --> 00:12:41 kind. If you could see it with your eye, it
00:12:41 --> 00:12:43 would look bigger than the full Moon.
00:12:43 --> 00:12:46 Avery: And, um, something was hiding behind it.
00:12:46 --> 00:12:49 Anna: Next to it, there's a much fainter object
00:12:49 --> 00:12:51 called G189 6
00:12:51 --> 00:12:54 3. It was first picked up in
00:12:54 --> 00:12:57 1994 by the German ROSAT
00:12:57 --> 00:12:59 satellite as a faint X ray glow.
00:12:59 --> 00:13:02 And later the Russian German spectrum
00:13:02 --> 00:13:05 Rontgen Gamma Observatory saw shell like
00:13:05 --> 00:13:07 structures in it, which suggested it was also
00:13:07 --> 00:13:10 a supernova remnant. But it sits right
00:13:10 --> 00:13:13 up against the glare of the jellyfish, and
00:13:13 --> 00:13:14 that glare drowns it.
00:13:15 --> 00:13:17 Avery: So how did they finally separate them?
00:13:18 --> 00:13:20 Anna: 16 years of data from NASA's Fermi
00:13:20 --> 00:13:23 Gamma Ray Space Telescope. The team led
00:13:23 --> 00:13:26 by Miltiades Michaelides, a
00:13:26 --> 00:13:29 postdoctoral fellow at Stanford, essentially
00:13:29 --> 00:13:31 subtracted the jellyfish out, isolated
00:13:31 --> 00:13:34 its gamma ray emission and looked at what was
00:13:34 --> 00:13:35 left underneath.
00:13:35 --> 00:13:37 Avery: And, um, there was something left.
00:13:37 --> 00:13:38 Anna: There was G
00:13:38 --> 00:13:41 189.63 is
00:13:41 --> 00:13:44 independently producing gamma rays. Which
00:13:44 --> 00:13:47 matters enormously because gamma rays mean
00:13:47 --> 00:13:49 particle acceleration, and particle
00:13:49 --> 00:13:51 acceleration is what a supernova remnant
00:13:51 --> 00:13:54 does. It's the shock wave doing work.
00:13:54 --> 00:13:56 Avery: Mikhail Adiz had a nice way of putting that,
00:13:56 --> 00:13:57 didn't he?
00:13:57 --> 00:14:00 Anna: He compared it to a drop of water falling on
00:14:00 --> 00:14:03 a still lake. The ripples spread out from
00:14:03 --> 00:14:06 the point of contact. A supernova remnant
00:14:06 --> 00:14:08 does exactly the same thing. And if you can
00:14:08 --> 00:14:11 see the ripples, you know, something dropped.
00:14:11 --> 00:14:14 Avery: So we have two remnants next to each other.
00:14:14 --> 00:14:16 How do we know they're related rather than
00:14:16 --> 00:14:18 just an accident of line of sight?
00:14:18 --> 00:14:21 Anna: This is the elegant part. There's a filament
00:14:21 --> 00:14:23 of gas arcing between them. And that
00:14:23 --> 00:14:25 filament is where the shock wave from
00:14:25 --> 00:14:28 G189.6 3
00:14:28 --> 00:14:31 has slammed into the same molecular cloud
00:14:31 --> 00:14:33 that the jellyfish is pushing against.
00:14:33 --> 00:14:36 Avery: Same cloud so same distance, same
00:14:36 --> 00:14:37 cloud.
00:14:37 --> 00:14:40 Anna: Same distance, same neighborhood. They're not
00:14:40 --> 00:14:43 one in front of the other. They're genuinely
00:14:43 --> 00:14:45 next door to each other. And that's what
00:14:45 --> 00:14:47 makes the shared origin story credible.
00:14:48 --> 00:14:49 Avery: So walk me through the story they're
00:14:49 --> 00:14:50 proposing.
00:14:50 --> 00:14:52 Anna: A tale of two massive stars
00:14:52 --> 00:14:55 born together, gravitationally bound,
00:14:55 --> 00:14:58 orbiting extremely closely, perhaps
00:14:58 --> 00:15:01 only a few times the Earth's sun distance
00:15:01 --> 00:15:04 apart. Close enough that material was likely
00:15:04 --> 00:15:07 flowing from one to the other. And then the
00:15:07 --> 00:15:09 bigger one runs out of fuel and detonates.
00:15:09 --> 00:15:11 Avery: And, um. The explosion breaks the
00:15:11 --> 00:15:12 partnership.
00:15:12 --> 00:15:15 Anna: The explosion breaks the partnership. The
00:15:15 --> 00:15:17 binary is disrupted and the surviving
00:15:17 --> 00:15:20 companion is essentially kicked flung
00:15:20 --> 00:15:23 off through the galaxy on its own. It keeps
00:15:23 --> 00:15:26 traveling, and tens of thousands of years
00:15:26 --> 00:15:27 later, it explodes too.
00:15:28 --> 00:15:29 Avery: How far apart did they end up?
00:15:30 --> 00:15:32 Anna: The centers of the two explosions are now
00:15:32 --> 00:15:35 somewhere between 30 and 50 light years
00:15:35 --> 00:15:38 apart. Two stars that were once close enough
00:15:38 --> 00:15:41 to be exchanging material, now separated
00:15:41 --> 00:15:44 by that gap. And each marked by its own
00:15:44 --> 00:15:45 expanding shell.
00:15:45 --> 00:15:46 Avery: What were they?
00:15:46 --> 00:15:49 Anna: The jellyfish's progenitor is thought to have
00:15:49 --> 00:15:52 been something like 15 to 25 times
00:15:52 --> 00:15:55 the mass of the Sun. Its companion at
00:15:55 --> 00:15:57 least 20. Both were probably tens
00:15:57 --> 00:16:00 of thousands times more luminous than the
00:16:00 --> 00:16:02 sun. And both may now be neutron
00:16:02 --> 00:16:03 stars.
00:16:03 --> 00:16:05 Avery: And, um, publication status because I know
00:16:05 --> 00:16:07 this was previewed at a conference.
00:16:07 --> 00:16:10 Anna: Good flag. Miltiais presented the results at
00:16:10 --> 00:16:13 the American Astronomical Society meeting in
00:16:13 --> 00:16:15 Pasadena back in June. What's happened this
00:16:15 --> 00:16:18 week is the peer reviewed paper. It's in
00:16:18 --> 00:16:20 Nature communications with the Stanford
00:16:20 --> 00:16:22 release. And wider coverage landing on the
00:16:22 --> 00:16:23 21st.
00:16:23 --> 00:16:26 Avery: And one for our listeners. Can we go and look
00:16:26 --> 00:16:27 at any of this?
00:16:27 --> 00:16:30 Anna: Not this month. Wherever you are. Gemini
00:16:30 --> 00:16:33 is close to the sun at the moment. So it's
00:16:33 --> 00:16:35 lost in the glare globally. But it comes
00:16:35 --> 00:16:38 back. And this is one where Northern
00:16:38 --> 00:16:40 hemisphere listeners get the better deal.
00:16:40 --> 00:16:43 From North America and Europe, Gemini
00:16:43 --> 00:16:45 rides high overhead through winter
00:16:45 --> 00:16:48 December into March. And the jellyfish
00:16:48 --> 00:16:51 sits. Beautifully placed for a telescope or a
00:16:51 --> 00:16:52 long exposure.
00:16:52 --> 00:16:55 Avery: And from down here we still get it.
00:16:55 --> 00:16:57 Anna: Just lower from Australia and New Zealand,
00:16:57 --> 00:17:00 Gemini comes up in the northern sky through
00:17:00 --> 00:17:02 our summer. Visible, worth hunting,
00:17:03 --> 00:17:06 but closer to the horizon. Either way, put
00:17:06 --> 00:17:08 it on the list for the end of the year. And
00:17:08 --> 00:17:10 bear in mind the jellyfish is faint. It would
00:17:10 --> 00:17:12 be bigger than the full moon if your eye
00:17:12 --> 00:17:15 could pick it up. But it needs photography or
00:17:15 --> 00:17:17 a decent aperture to show itself.
00:17:17 --> 00:17:20 Avery: Anna, uh, here's something we know exists but
00:17:20 --> 00:17:22 have never actually been able to draw.
00:17:22 --> 00:17:24 Galaxy clusters. The largest
00:17:24 --> 00:17:27 gravitationally bound structures in the
00:17:27 --> 00:17:29 universe. Hundreds or thousands of
00:17:29 --> 00:17:32 galaxies plus enormous clouds of hot gas,
00:17:32 --> 00:17:35 plus dark matter Are threaded through
00:17:35 --> 00:17:36 with magnetic fields.
00:17:37 --> 00:17:38 Anna: We've known that for decades.
00:17:39 --> 00:17:41 Avery: What we have never done is map the shape of
00:17:41 --> 00:17:44 one across an entire cluster from the
00:17:44 --> 00:17:46 middle right out to the edge.
00:17:46 --> 00:17:47 Anna: And now somebody has.
00:17:48 --> 00:17:50 Avery: A team led by Andrea, uh, Boton at innaf,
00:17:51 --> 00:17:53 Italy's National Astrophysics institute, Has
00:17:53 --> 00:17:56 reconstructed the magnetic field of Galaxy
00:17:56 --> 00:17:59 cluster Abell 2255. And I
00:17:59 --> 00:18:01 want to be precise about that name because at
00:18:01 --> 00:18:03 least one outlet has got it wrong this week
00:18:03 --> 00:18:06 and called it Abell 2142.
00:18:06 --> 00:18:09 It is Abell 2255,
00:18:09 --> 00:18:11 about a billion light years away.
00:18:11 --> 00:18:12 Anna: Why that cluster?
00:18:13 --> 00:18:15 Avery: Because it's famously messy in radio.
00:18:15 --> 00:18:18 Abell 2255 has long been known for
00:18:18 --> 00:18:21 its complexity. It's full of strange, diffuse
00:18:21 --> 00:18:24 radio structures, Halos and filaments, which
00:18:24 --> 00:18:26 is exactly what you want if you're trying to
00:18:26 --> 00:18:28 trace magnetic fields, because those
00:18:28 --> 00:18:31 structures are made by energetic electrons
00:18:31 --> 00:18:32 spiraling along magnetic lines.
00:18:33 --> 00:18:35 Anna: So the radio emission is the field
00:18:35 --> 00:18:37 effectively made visible.
00:18:37 --> 00:18:40 Avery: It's the tracer. Electrons corkscrewing
00:18:40 --> 00:18:42 along magnetic lines give off radio waves.
00:18:43 --> 00:18:45 So if you can see the emission finely enough,
00:18:45 --> 00:18:48 you can work backwards to the field. The
00:18:48 --> 00:18:50 problem has always been that these signals
00:18:50 --> 00:18:52 are extraordinarily faint.
00:18:52 --> 00:18:55 Anna: What did they observe with lofar, the
00:18:55 --> 00:18:57 Avery: low frequency array, the European radial
00:18:57 --> 00:19:00 telescope spread across a continent. And
00:19:00 --> 00:19:02 these are the deepest radio observations ever
00:19:02 --> 00:19:05 made of a galaxy cluster that was combined
00:19:05 --> 00:19:07 with a new data analysis technique. And
00:19:07 --> 00:19:09 between them, that's what cracked it.
00:19:09 --> 00:19:11 Anna: And what does the map show?
00:19:11 --> 00:19:14 Avery: This is defining in some regions of the
00:19:14 --> 00:19:16 cluster, the magnetic field lines are
00:19:16 --> 00:19:19 strikingly coherent. They follow very
00:19:19 --> 00:19:21 specific directions stretching radially
00:19:21 --> 00:19:24 outward along the extended radial structures.
00:19:24 --> 00:19:26 Anna: They're not random, which tells you something
00:19:26 --> 00:19:28 made them that way, which tells you
00:19:28 --> 00:19:31 Avery: something is organizing them. And Boton's
00:19:31 --> 00:19:33 conclusion is that the shape of the field is
00:19:33 --> 00:19:36 intimately linked to the motion of the gas it
00:19:36 --> 00:19:38 sits in. The field gets stretched and
00:19:38 --> 00:19:41 compressed by the movements associated with
00:19:41 --> 00:19:42 the cluster's own formation.
00:19:43 --> 00:19:45 Anna: So the cluster assembling itself is what
00:19:45 --> 00:19:46 shapes the magnetism?
00:19:47 --> 00:19:49 Avery: That's the argument, and it's the first
00:19:49 --> 00:19:51 observational evidence of it. The same
00:19:51 --> 00:19:54 violent process that builds a galaxy cluster,
00:19:54 --> 00:19:57 Gas falling in, sloshing, colliding,
00:19:57 --> 00:20:00 merging, is the process that combs the
00:20:00 --> 00:20:02 magnetic field into the pattern we now see.
00:20:02 --> 00:20:05 Anna: And that ties into the radio halos question.
00:20:05 --> 00:20:08 Avery: It does. Bolton says they believe the
00:20:08 --> 00:20:10 mechanism that switches on these gigantic
00:20:10 --> 00:20:13 radio emissions is linked to the formation
00:20:13 --> 00:20:16 process of the clusters themselves. So the
00:20:16 --> 00:20:18 map isn't just a pretty picture. It's the
00:20:18 --> 00:20:19 evidence for the engine.
00:20:19 --> 00:20:22 Anna: The. It's a lovely Example of the thing radio
00:20:22 --> 00:20:25 astronomy does best, showing you a
00:20:25 --> 00:20:28 Avery: structure that is completely invisible, is a
00:20:28 --> 00:20:30 billion light years away, is bigger than
00:20:30 --> 00:20:32 anything else in the universe, and has been
00:20:32 --> 00:20:35 sitting there the entire time. Published in,
00:20:35 --> 00:20:37 uh, Astronomy and Astrophysics.
00:20:37 --> 00:20:40 Anna: Every if you want to know what has hit the
00:20:40 --> 00:20:41 Earth, don't look at
00:20:41 --> 00:20:43 Avery: the Earth because the Earth keeps erasing it
00:20:44 --> 00:20:44 constantly.
00:20:45 --> 00:20:47 Anna: Plate tectonics, volcanism, weather,
00:20:47 --> 00:20:50 water, erosion. Craters get buried,
00:20:50 --> 00:20:53 distorted, subducted, destroyed. The
00:20:53 --> 00:20:55 practical consequence is that geological
00:20:55 --> 00:20:57 evidence for impacts older than about
00:20:57 --> 00:21:00 650 million years is
00:21:00 --> 00:21:01 extremely scarce here.
00:21:02 --> 00:21:03 Avery: And the Moon doesn't do any of that.
00:21:03 --> 00:21:06 Anna: No plate tectonics, no flowing water, no
00:21:06 --> 00:21:09 meaningful atmosphere. The Moon just keeps
00:21:09 --> 00:21:11 the receipts. And when you read those
00:21:11 --> 00:21:14 receipts carefully, there's a spike. When,
00:21:14 --> 00:21:16 uh, around 800 million years ago,
00:21:17 --> 00:21:19 there's a surge in large lunar impacts. And
00:21:19 --> 00:21:22 it shows up in two independent ways. One
00:21:22 --> 00:21:25 is the estimated ages of big craters,
00:21:25 --> 00:21:27 including copernicus, which is 93
00:21:27 --> 00:21:30 kilometers across. The other is impact
00:21:30 --> 00:21:30 glass.
00:21:31 --> 00:21:33 Avery: Explain impact glass.
00:21:33 --> 00:21:35 Anna: When something hits hard enough, the heat
00:21:35 --> 00:21:38 melts. Rock that melt cools into
00:21:38 --> 00:21:41 glass, and the glass locks in a, uh, chemical
00:21:41 --> 00:21:44 timestamp. The Apollo missions brought a lot
00:21:44 --> 00:21:46 of it home. And when you look at the age
00:21:46 --> 00:21:48 distribution of that glass, you see the same
00:21:48 --> 00:21:50 spike at 800 million years.
00:21:51 --> 00:21:53 Avery: So two different methods agree that something
00:21:53 --> 00:21:55 happened, but nobody knew what.
00:21:55 --> 00:21:58 Anna: Nobody knew what. That's the puzzle that's
00:21:58 --> 00:22:00 been sitting there for decades. And a new
00:22:00 --> 00:22:03 paper led by Dr. William Bakke at the
00:22:03 --> 00:22:05 Southwest Research Institute in Boulder
00:22:05 --> 00:22:08 proposes a specific culprit, which is
00:22:08 --> 00:22:11 an asteroid called Eulalia, or rather
00:22:11 --> 00:22:13 the parent body of the family of asteroids we
00:22:13 --> 00:22:16 now call Eulalia. Uh, because the object, its
00:22:17 --> 00:22:19 no longer exists. It was catastrophically
00:22:19 --> 00:22:22 broken apart in a collision in the main belt.
00:22:22 --> 00:22:24 Avery: And the location of that breakup matters.
00:22:25 --> 00:22:27 Anna: The location is everything. It happened right
00:22:27 --> 00:22:30 next to what's called the J3 to one resonance
00:22:30 --> 00:22:33 with Jupiter. And a resonance like that is
00:22:33 --> 00:22:35 essentially a gravitational trapdoor.
00:22:35 --> 00:22:37 Material that wanders into it, gets its
00:22:37 --> 00:22:40 orbit, pumped up by Jupiter and flung into
00:22:40 --> 00:22:41 the inner solar system.
00:22:41 --> 00:22:44 Avery: So the shrapnel had a delivery mechanism
00:22:44 --> 00:22:45 waiting right there.
00:22:45 --> 00:22:48 Anna: It had an open door right next to it. And the
00:22:48 --> 00:22:51 simulations show what happened in two phases.
00:22:51 --> 00:22:53 Half the fragments reached the resonance
00:22:53 --> 00:22:55 almost immediately. That's the prompt
00:22:55 --> 00:22:58 bombardment Planetary shrapnel sprayed across
00:22:58 --> 00:22:59 the inner solar system.
00:22:59 --> 00:23:01 Avery: And, um, the other half, over the
00:23:01 --> 00:23:04 Anna: following 100 to 150 million
00:23:04 --> 00:23:06 years, another quarter of the fragments
00:23:06 --> 00:23:08 drifted into the resonance more slowly,
00:23:08 --> 00:23:11 pushed by something called the Yarkovsky
00:23:11 --> 00:23:14 effect, which is what, in plain terms it's
00:23:14 --> 00:23:16 sunlight doing work. A rotating asteroid
00:23:16 --> 00:23:19 absorbs sunlight on one side and
00:23:19 --> 00:23:21 reradiates that heat as it turns. That
00:23:21 --> 00:23:24 reradiation gives an incredibly gentle
00:23:24 --> 00:23:27 push. On a human scale, it's nothing. Over
00:23:27 --> 00:23:30 a hundred million years, it can move an
00:23:30 --> 00:23:32 asteroid's orbit enough to drop it into a
00:23:32 --> 00:23:33 trapdoor.
00:23:33 --> 00:23:36 Avery: So this wasn't one bad afternoon. This was a
00:23:36 --> 00:23:37 long siege.
00:23:37 --> 00:23:39 Anna: That's the reframing, I think, is genuinely
00:23:39 --> 00:23:42 important here. Not an event, an episode,
00:23:42 --> 00:23:45 a bombardment that opened suddenly and then
00:23:45 --> 00:23:48 kept going for well over 100 million years.
00:23:48 --> 00:23:50 Avery: And what does that mean for Earth?
00:23:50 --> 00:23:52 Anna: Here's the number that changes the scale of
00:23:52 --> 00:23:55 it. For every large impact recorded on the
00:23:55 --> 00:23:58 moon, roughly 20 similar or larger
00:23:58 --> 00:24:00 impacts hit the Earth, where a bigger target
00:24:00 --> 00:24:01 with stronger gravity.
00:24:02 --> 00:24:03 Avery: 20 to 1.
00:24:03 --> 00:24:06 Anna: 20 to 1. So a spike on the Moon
00:24:06 --> 00:24:09 means a barrage down here. And now look
00:24:09 --> 00:24:11 at what else was happening around 800 million
00:24:11 --> 00:24:14 years ago. That is the run up to one of the
00:24:14 --> 00:24:16 most dramatic climate episodes in our
00:24:16 --> 00:24:19 planet's history. Widespread global
00:24:19 --> 00:24:22 cooling and major shifts in the biosphere.
00:24:22 --> 00:24:24 Avery: Is he climbing a causal link?
00:24:25 --> 00:24:27 Anna: He's careful. And I want to be careful too.
00:24:28 --> 00:24:30 Bakke's phrasing is that given the peak of
00:24:30 --> 00:24:33 this barrage coincides with a period of
00:24:33 --> 00:24:35 widespread cooling and major shifts in our
00:24:35 --> 00:24:38 biosphere, it is tempting to suggest the
00:24:38 --> 00:24:41 former produced the latter. That is a
00:24:41 --> 00:24:44 hypothesis flagged as tempting, not a
00:24:44 --> 00:24:45 conclusion.
00:24:45 --> 00:24:48 Avery: Because so far, only one impact has ever
00:24:48 --> 00:24:51 been firmly tied to a biological outcome.
00:24:51 --> 00:24:54 Anna: Pictxulub, 66 million years ago.
00:24:54 --> 00:24:57 The end of the dinosaurs. That's the one.
00:24:57 --> 00:24:58 Everything else is inference.
00:24:59 --> 00:25:01 Avery: So how would you ever test this?
00:25:02 --> 00:25:04 Anna: This is my favorite part of the paper. And
00:25:04 --> 00:25:06 it's the reason to keep an eye on this story.
00:25:07 --> 00:25:10 We have asteroid samples on Earth right now.
00:25:10 --> 00:25:12 Hayabusa2 brought material back from
00:25:12 --> 00:25:15 Ryugu in December 2020. Osiris
00:25:15 --> 00:25:17 Rex brought Bennu back in September
00:25:18 --> 00:25:20 2023. Both are under analysis.
00:25:21 --> 00:25:23 Avery: And if they carry the Eulalia fingerprint,
00:25:24 --> 00:25:26 Anna: if the mineralogy matches the Eulalia
00:25:26 --> 00:25:29 family, then we are holding in a laboratory
00:25:30 --> 00:25:32 physical samples of the material that rained
00:25:32 --> 00:25:35 on solar system 800 million
00:25:35 --> 00:25:38 years ago. That would turn a dynamical
00:25:38 --> 00:25:41 model into a direct compositional record.
00:25:41 --> 00:25:44 Avery: That's a remarkable thought. Brains in a lab
00:25:44 --> 00:25:47 in Japan and Texas. That might be pieces of
00:25:47 --> 00:25:50 the thing that helped freeze the Earth.
00:25:50 --> 00:25:53 Anna: Published in the Planetary Science Journal by
00:25:53 --> 00:25:55 Botke, with Volkerlitsky, Dykhuis and
00:25:55 --> 00:25:56 Zellner.
00:25:56 --> 00:25:56 Avery: Great.
00:25:56 --> 00:25:58 And our next story comes with a deadline.
00:25:58 --> 00:26:00 Wherever in the world you're listening.
00:26:00 --> 00:26:01 Anna: What's the urgency?
00:26:01 --> 00:26:04 Avery: The moon first quarter was yesterday,
00:26:04 --> 00:26:07 the 21st. Tonight it's a waxing
00:26:07 --> 00:26:10 gibbous. And every night from here it gets
00:26:10 --> 00:26:12 brighter and stays up longer, building to the
00:26:12 --> 00:26:15 buck. Moon full at 4:36 in the afternoon
00:26:15 --> 00:26:18 UTC on Wednesday the 29th.
00:26:18 --> 00:26:21 That's 10:36 in the morning Eastern time in
00:26:21 --> 00:26:23 the States and 12:36 on Thursday
00:26:23 --> 00:26:25 morning for us in Australia.
00:26:25 --> 00:26:28 Anna: And that matters because of what's peaking.
00:26:28 --> 00:26:31 Avery: The southern Delta Aquariates peak falls
00:26:31 --> 00:26:34 on the 30th, effectively the same night as
00:26:34 --> 00:26:36 the full moon. So the peak is going to be
00:26:36 --> 00:26:39 washed out, which means the practical advice
00:26:39 --> 00:26:41 is the same for everybody. Don't wait for
00:26:41 --> 00:26:44 peak night. This week is your window in the
00:26:44 --> 00:26:46 small hours while the moon still sets and
00:26:46 --> 00:26:48 leaves you real darkness before dawn.
00:26:49 --> 00:26:51 Anna: And this is a shower that favors us.
00:26:51 --> 00:26:54 Avery: It does. From Australia, New Zealand and
00:26:54 --> 00:26:57 southern Africa, the radiant sits high close
00:26:57 --> 00:27:00 to overhead, which is why the shower gets
00:27:00 --> 00:27:02 underrated. In the north, under genuinely
00:27:02 --> 00:27:05 dark skies, you might see 15 to 20
00:27:05 --> 00:27:08 an hour. And they're lovely meteors. Long,
00:27:08 --> 00:27:11 graceful streaks rather than quick flashes,
00:27:11 --> 00:27:13 and known for persistent trains, those
00:27:13 --> 00:27:16 glowing trails that hang in the air for a
00:27:16 --> 00:27:17 second or two afterwards.
00:27:17 --> 00:27:19 Anna: And northern listeners aren't shut out of
00:27:19 --> 00:27:22 Avery: this one, not at all. And I want to be clear
00:27:22 --> 00:27:24 about that, because this shower gets written
00:27:24 --> 00:27:27 off in the north too readily. If you're in
00:27:27 --> 00:27:29 North America, particularly the southern
00:27:29 --> 00:27:32 states, Texas, Florida, Arizona, the
00:27:32 --> 00:27:35 Gulf coast, the Delta Aquarids are a
00:27:35 --> 00:27:37 genuinely worthwhile watch. The radiance
00:27:37 --> 00:27:39 sits low in your southern sky rather than
00:27:39 --> 00:27:42 overhead, so you'll see fewer of them. But
00:27:42 --> 00:27:45 the ones you do catch travel long paths
00:27:45 --> 00:27:47 across the sky, and they can be spectacular.
00:27:47 --> 00:27:50 Best time is after midnight through to dawn.
00:27:50 --> 00:27:52 Southern Europe, the Mediterranean, North
00:27:52 --> 00:27:54 Africa. Same deal.
00:27:54 --> 00:27:55 Anna: And where do people look?
00:27:56 --> 00:27:58 Avery: The radiant is in Aquarius, near the star
00:27:58 --> 00:28:01 Delta Aquarii. Use Fomalhaut to find
00:28:01 --> 00:28:04 the region. But honestly, don't stare at
00:28:04 --> 00:28:07 the radiant. Lie back, take in as much sky as
00:28:07 --> 00:28:10 you can and let them come to you. Parent body
00:28:10 --> 00:28:12 is suspected to be Comet
00:28:12 --> 00:28:15 96PMachholz. There are also
00:28:15 --> 00:28:18 the Alpha Capricornids building to the 30th
00:28:18 --> 00:28:20 and 31st. Far fewer meteors, but
00:28:20 --> 00:28:23 few famous for slow, brilliant fireballs that
00:28:23 --> 00:28:25 can punch straight through moonlight.
00:28:25 --> 00:28:27 Anna: And for the north, there's something
00:28:27 --> 00:28:29 considerably bigger coming.
00:28:29 --> 00:28:32 Avery: There is, and if you're listening in North
00:28:32 --> 00:28:34 America or Europe, you should be planning for
00:28:34 --> 00:28:37 this. Now, two things land together on the
00:28:37 --> 00:28:40 12th of August 1st, the Perseids Peak.
00:28:40 --> 00:28:42 And this year the moon is new that same day,
00:28:42 --> 00:28:45 which means A properly dark sky that
00:28:45 --> 00:28:48 is the best Perseid year in some time. And
00:28:48 --> 00:28:51 the second, a, uh, total solar
00:28:51 --> 00:28:53 eclipse, the first on mainland Europe
00:28:53 --> 00:28:56 since 1999 and the first in Spain
00:28:56 --> 00:28:59 since 1905. Totality sweeps
00:28:59 --> 00:29:02 across the Arctic, Greenland, Iceland and
00:29:02 --> 00:29:05 northern Spain. And in Spain, it happens
00:29:05 --> 00:29:07 close to sunset, with the sun only a few
00:29:07 --> 00:29:10 degrees above the horizon, which could be
00:29:10 --> 00:29:11 extraordinary.
00:29:11 --> 00:29:14 Anna: North America doesn't get totality this time.
00:29:15 --> 00:29:18 Avery: No, and I won't oversell it, but there is a
00:29:18 --> 00:29:20 real partial eclipse across much of the
00:29:20 --> 00:29:23 continent. Alaska gets the deepest view
00:29:23 --> 00:29:26 near sunrise. Atlantic Canada gets
00:29:26 --> 00:29:28 roughly half the sun covered at maximum in
00:29:28 --> 00:29:30 the afternoon. New England and the
00:29:30 --> 00:29:32 northeastern states get a smaller bite. And
00:29:32 --> 00:29:35 there's some coverage visible right across
00:29:35 --> 00:29:37 every Canadian province and the northern
00:29:37 --> 00:29:39 contiguous states, though.
00:29:39 --> 00:29:40 Anna: Dig out the glasses.
00:29:41 --> 00:29:43 Avery: Dig out the eclipse glasses from 2024 and
00:29:43 --> 00:29:45 check their ISO 1, uh,
00:29:45 --> 00:29:48 23122 certified.
00:29:48 --> 00:29:51 It will not get dark even with 50%
00:29:51 --> 00:29:53 coverage. The remaining sun is blindingly
00:29:53 --> 00:29:56 bright, so there is never a safe moment to
00:29:56 --> 00:29:58 look without protection and the lovely
00:29:58 --> 00:30:00 detail. If you're standing in the path of
00:30:00 --> 00:30:03 totality in Spain or Iceland, there's a
00:30:03 --> 00:30:05 genuine chance of a Perseid streaking pass
00:30:05 --> 00:30:07 during those two minutes.
00:30:07 --> 00:30:10 Anna: And tonight for everyone, the Milky
00:30:10 --> 00:30:10 Way
00:30:11 --> 00:30:13 Avery: from the Southern Hemisphere, the galactic
00:30:13 --> 00:30:16 core is riding high overhead right now. One
00:30:16 --> 00:30:18 of the real privileges of our winter, and
00:30:18 --> 00:30:20 it's at its best. From the Northern
00:30:20 --> 00:30:22 Hemisphere, it's lower in the south towards
00:30:22 --> 00:30:25 Sagittarius. But on a dark night, it's still
00:30:25 --> 00:30:28 magnificent. And before dawn, Saturn and
00:30:28 --> 00:30:30 Mars are in the eastern sky for both
00:30:30 --> 00:30:31 hemispheres.
00:30:31 --> 00:30:33 Anna: One more thing before we go.
00:30:33 --> 00:30:36 Avery: The launchers SpaceX is targeting Thursday
00:30:36 --> 00:30:39 the 23rd for Starship Flight 13.
00:30:39 --> 00:30:42 Window opening at 6:45 in the evening
00:30:42 --> 00:30:45 Eastern Time. That's 5:45 Central,
00:30:45 --> 00:30:48 3:45 Pacific and Friday morning,
00:30:48 --> 00:30:51 quarter to nine for us in Australia. 20
00:30:51 --> 00:30:54 Starlink V3 satellites aboard. Second
00:30:54 --> 00:30:57 flight of the V3 vehicle dead and alarm.
00:30:57 --> 00:30:59 And as always with starship, check before you
00:30:59 --> 00:31:02 commit the date has already moved twice.
00:31:03 --> 00:31:06 Anna: That's Astronomy daily for Wednesday 22
00:31:06 --> 00:31:08 July, a mechanic on its way to
00:31:08 --> 00:31:10 geostationary orbit, a rocket stage
00:31:10 --> 00:31:13 two, two weeks from making a new crater, and
00:31:13 --> 00:31:16 23 astronomers asking the world to watch
00:31:17 --> 00:31:17 two
00:31:17 --> 00:31:20 Avery: stars that died in sequence and left their
00:31:20 --> 00:31:22 remnants side by side. The first magnetic
00:31:22 --> 00:31:25 map of a galaxy cluster and an asteroid
00:31:25 --> 00:31:27 breakup that may have been raining down on us
00:31:27 --> 00:31:28 while the Earth froze.
00:31:29 --> 00:31:31 Anna: Donotes sources and links are all at
00:31:31 --> 00:31:34 astronomydaily IO and you can find us
00:31:34 --> 00:31:37 at astrodaily Pod across the socials.
00:31:37 --> 00:31:39 Avery: If you enjoy the show, a, uh, rating or
00:31:39 --> 00:31:41 review genuinely helps other people find us.
00:31:42 --> 00:31:44 Astronomy Daily is part of the bytes.com
00:31:44 --> 00:31:45 podcast network.
00:31:45 --> 00:31:46 Anna: I'm Anna.
00:31:46 --> 00:31:49 Avery: And I'm, um, Avery. Get outside this week. It
00:31:49 --> 00:31:50 won't be dark for long.
00:31:50 --> 00:31:51 Anna: Clear skies.