Electrons made on the wrong side of Earth's 'impenetrable barrier', a gamma-ray burst that only looked weak, the week that was, and a Halloween that is astronomically a week early. The Wall That Broke In 2014 NASA's Van Allen Probes revealed a sharp inner edge to Earth's outer radiation belt: electrons at the very highest energies never got closer than about 2.8 Earth radii. During the May 2024 superstorm — the biggest since the 2003 Halloween storms — Japan's Arase satellite saw electrons of about 3 MeV rise deep inside that 'impenetrable barrier'. A new paper led by Yoshizumi Miyoshi (Nagoya University ISEE) shows a peak in electron phase space density growing in place at L* ≈ 3, about 12,000 km up — evidence the electrons were accelerated there rather than carried in. Intense chorus waves, operating in a region emptied by a crushed plasmasphere and a negative ionospheric storm, are the likely engine. Caveats: one storm; 'consistent with' chorus acceleration; the breach itself had been reported before — the new part is the mechanism. Not Faint, Just Side-On GRB 260310A, caught by Fermi on 10 March 2026, had a feeble gamma-ray flash but one of the brightest afterglows ever seen. Yu-Han Yang (Tor Vergata) and colleagues argue we viewed a two-component jet from the side. Preprint from May; published in ApJL this month; competing models exist. The Week That Was E214 GRB 160425A, one burst with two births · E215 θ¹ Ori C, the star born twice · E216 Rubin's first dwarf-planet candidate 2026 ED138 · E217 Betelgeuse pulled out of round by Siwarha · E218 Teghaza 001, one of the oldest pieces of Mars. Plus Swift's re-entry watch, Voyager 1 at one light-day on 18 Nov, and Starship Flight 15 targeted for November. Skywatch Halloween is astronomically a week early (true cross-quarter 7 Nov). Mars, Jupiter and Regulus line up before dawn, Mars–Jupiter just over 1° apart on 16 Nov. Moon near Mars and Jupiter on the mornings of 2–3 Nov. Saturn rules the evening, best from the south. US clocks fall back 1 Nov. Solar viewing only with ISO 12312-2 certified filters. Sources · Miyoshi et al., GRL 53, e2026GL125879 (2026) — https://doi.org/10.1029/2026GL125879 · ISAS/JAXA release, 27 Oct 2026 (Japanese) — https://www.isas.jaxa.jp/topics/004417.html · Nagoya University release via phys.org — https://phys.org/news/2026-10-solar-storm-triggered-ultrarelativistic-electrons.html · Yang et al., ApJL 1011 L22 (GRB 260310A) — https://iopscience.iop.org/article/10.3847/2041-8213/aea990 · arXiv 2605.23818 (Yang et al. preprint) — https://arxiv.org/abs/2605.23818 · Gill et al., arXiv 2605.26091 (competing model) — https://arxiv.org/abs/2605.26091 · NASA: Swift mission ends ahead of re-entry — https://science.nasa.gov/blogs/swift/2026/10/23/nasas-swift-mission-ends-ahead-of-re-entry/
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This episode includes AI-generated content.
00:00:00 --> 00:00:03 Anna: Happy Halloween. And if you want something
00:00:03 --> 00:00:05 properly spooky for the occasion, try this.
00:00:06 --> 00:00:08 Wrapped around the Earth is a boundary that,
00:00:08 --> 00:00:11 uh, space physicists have spent more than a
00:00:11 --> 00:00:13 decade calling the impenetrable
00:00:13 --> 00:00:15 barrier. A line that the most
00:00:16 --> 00:00:19 dangerous electrons in near Earth space were
00:00:19 --> 00:00:20 simply never seen to cross.
00:00:20 --> 00:00:23 Avery: Then in May 2024, the
00:00:23 --> 00:00:26 biggest geomagnetic storm since the famous
00:00:26 --> 00:00:28 Halloween Storms of 2003 hit the planet
00:00:29 --> 00:00:31 and a Japanese satellite watched electrons
00:00:31 --> 00:00:34 moving at nearly the speed of light turn up
00:00:34 --> 00:00:36 on the wrong side of the wall.
00:00:36 --> 00:00:38 Anna: The paper explaining how they got there came
00:00:38 --> 00:00:41 out this week. Short version, they didn't
00:00:41 --> 00:00:43 break in. They were made in there.
00:00:44 --> 00:00:46 Welcome to Astronomy AstroDailyPod and to the
00:00:46 --> 00:00:49 weekend wrap for Saturday 31st October.
00:00:49 --> 00:00:50 I'm Anna.
00:00:50 --> 00:00:53 Avery: And I'm Avery. Today, the wall that
00:00:53 --> 00:00:56 broke, a gamma ray burst that only
00:00:56 --> 00:00:58 looked feeble because it was pointing the
00:00:58 --> 00:01:01 wrong way. Then the week that was.
00:01:01 --> 00:01:04 And a Halloween that turns out to be a week
00:01:04 --> 00:01:05 early. Let's go.
00:01:06 --> 00:01:08 Anna: Let's start with the neighbourhood. In
00:01:08 --> 00:01:11 1958, America's first
00:01:11 --> 00:01:13 satellite, Explorer 1, carried a, uh,
00:01:13 --> 00:01:16 Geiger counter built by James Van Allen's
00:01:16 --> 00:01:19 team. And it found that Earth
00:01:19 --> 00:01:22 is wrapped in radiation charged
00:01:22 --> 00:01:25 particles from the sun and from cosmic rays
00:01:25 --> 00:01:28 trapped by our magnetic field into
00:01:28 --> 00:01:31 two doughnut shaped zones. The Van Allen
00:01:31 --> 00:01:31 belts.
00:01:31 --> 00:01:34 Avery: Roughly speaking, the inner belt is
00:01:34 --> 00:01:37 dominated by energetic protons and
00:01:37 --> 00:01:40 the outer belt by electrons. And
00:01:40 --> 00:01:42 the outer belt is the restless one.
00:01:43 --> 00:01:46 A solar storm can empty it, uh, in hours
00:01:46 --> 00:01:48 or thousand, fill it with electrons
00:01:48 --> 00:01:50 travelling at a very large fraction of the
00:01:50 --> 00:01:51 speed of light.
00:01:51 --> 00:01:54 Anna: Those are the ones satellite engineers worry
00:01:54 --> 00:01:57 about. Electrons above a few million
00:01:57 --> 00:02:00 electron volts can punch through shielding,
00:02:00 --> 00:02:03 build up charge inside electronics and
00:02:03 --> 00:02:06 discharge operators have a blunt
00:02:06 --> 00:02:09 nickname for killer electrons.
00:02:09 --> 00:02:12 Avery: In 2014, Dan Baker's team using
00:02:12 --> 00:02:15 NASA's twin Van Allen probes reported
00:02:15 --> 00:02:18 something odd about those killer electrons.
00:02:18 --> 00:02:20 The outer belt had a, uh, remarkably sharp
00:02:20 --> 00:02:23 inner edge. However hard a storm pushed,
00:02:24 --> 00:02:26 electrons at the very highest energies
00:02:26 --> 00:02:29 stopped at about 2.8 Earth radii
00:02:29 --> 00:02:32 measured out at the magnetic equator. The
00:02:32 --> 00:02:34 paper described it as a nearly impenetrable
00:02:34 --> 00:02:36 barrier and the name stuck.
00:02:36 --> 00:02:39 Anna: Quick note on the units because they'll
00:02:40 --> 00:02:42 space physicists map the belts with a number
00:02:42 --> 00:02:45 called l. It's the distance
00:02:45 --> 00:02:48 in Earth radii from Earth centre
00:02:48 --> 00:02:51 at which a magnetic field line crosses the
00:02:51 --> 00:02:54 magnetic equator. L of 3 is about
00:02:54 --> 00:02:56 12 kilometres above the surface.
00:02:57 --> 00:02:59 Avery: And the explanation for the barrier was
00:02:59 --> 00:03:02 roughly this. Inside it sits the plasma
00:03:02 --> 00:03:05 sphere, a dense cloud of cool, low
00:03:05 --> 00:03:07 energy plasma that leaks up from the
00:03:07 --> 00:03:09 ionosphere. In that environment the waves
00:03:09 --> 00:03:12 that scatter electrons away win out over
00:03:12 --> 00:03:15 the slow processes that carry them inward.
00:03:15 --> 00:03:18 Electrons creep in, get knocked out
00:03:18 --> 00:03:19 and never build up
00:03:20 --> 00:03:23 Anna: a wall. In other words, that's really a
00:03:23 --> 00:03:25 balance. And balances can tip.
00:03:26 --> 00:03:28 Avery: On the 10th and 11th of May
00:03:28 --> 00:03:31 2024, a run of eruptions from one
00:03:31 --> 00:03:34 huge sunspot group hit Earth. It
00:03:34 --> 00:03:36 was the strongest geomagnetic storm in more
00:03:36 --> 00:03:39 than 20 years, the largest since the
00:03:39 --> 00:03:41 Halloween storms of 2003.
00:03:41 --> 00:03:44 Aurora was seen at, uh, latitudes that almost
00:03:44 --> 00:03:47 never get it in both hemispheres. Here in
00:03:47 --> 00:03:49 Australia, the Aurora Australis was
00:03:49 --> 00:03:51 photographed much further north than usual.
00:03:52 --> 00:03:54 And Japan, which rarely sees aurora at all,
00:03:54 --> 00:03:55 saw it too.
00:03:56 --> 00:03:59 Anna: And one spacecraft was in exactly the right
00:03:59 --> 00:04:01 place. Arase, launched by
00:04:01 --> 00:04:04 Jaxa in December 2016, flies
00:04:04 --> 00:04:07 an elongated orbit close to the magnetic
00:04:07 --> 00:04:09 equator, straight through the belts.
00:04:10 --> 00:04:12 Crucially, it measures everything at
00:04:13 --> 00:04:16 the electrons across a huge range of energies
00:04:16 --> 00:04:19 the magnetic field, the plasma waves and
00:04:19 --> 00:04:21 the density of the cold plasma. Its
00:04:21 --> 00:04:24 science centre is run jointly by JAXA's
00:04:24 --> 00:04:26 Institute of Space and Astronautical Science
00:04:26 --> 00:04:28 and Nagoya University.
00:04:29 --> 00:04:32 Avery: Here's what Arase saw. After the main
00:04:32 --> 00:04:35 phase of the storm, electrons at around 3
00:04:35 --> 00:04:38 million electron volts climbed sharply inside
00:04:38 --> 00:04:40 the barrier. The team went back through the
00:04:40 --> 00:04:43 whole record to 2017. In
00:04:43 --> 00:04:45 ordinary storms, nothing gets in at those
00:04:45 --> 00:04:48 energies. May 2024
00:04:48 --> 00:04:51 stands alone. It was the largest increase of
00:04:51 --> 00:04:54 high energy electrons Arasi has recorded,
00:04:54 --> 00:04:56 and the enhanced levels persisted for weeks.
00:04:57 --> 00:05:00 Anna: Which leaves the real question. And it's the
00:05:00 --> 00:05:03 subject of the new paper led by Yoshizumi
00:05:03 --> 00:05:06 Miyoshi of, uh, Nagoya University's Institute
00:05:06 --> 00:05:08 for Space Earth Environmental Research,
00:05:08 --> 00:05:11 published this week in Geophysical Research
00:05:11 --> 00:05:14 Letters. Were those electrons carried in
00:05:14 --> 00:05:17 from outside or were they accelerated
00:05:17 --> 00:05:18 right where they were found?
00:05:19 --> 00:05:21 Avery: The test is a quantity called
00:05:21 --> 00:05:24 phase space density. Think of a
00:05:24 --> 00:05:27 footpath crowded with people. If everyone
00:05:27 --> 00:05:30 arrived through a gate at one end. The crowd
00:05:30 --> 00:05:32 is thickest by the gate and thins out along
00:05:32 --> 00:05:35 the path. If a bus pulls up in the middle
00:05:35 --> 00:05:38 and let everyone off, the crowd peaks in the
00:05:38 --> 00:05:40 middle and spreads both ways.
00:05:40 --> 00:05:43 Anna: And to compare like with like, you
00:05:43 --> 00:05:46 track electrons with the same underlying
00:05:46 --> 00:05:48 orbital properties, not just the same energy,
00:05:49 --> 00:05:52 because an electron moving inward naturally
00:05:52 --> 00:05:55 gains energy as the field strengths. Getting
00:05:55 --> 00:05:57 that right needs measurements near the
00:05:57 --> 00:05:59 magnetic equator over a wide energy
00:05:59 --> 00:06:02 range. That's exactly a rasae specialty.
00:06:03 --> 00:06:06 Avery: The result? During the storm's recovery,
00:06:06 --> 00:06:09 a clear peak in phase space density formed
00:06:09 --> 00:06:11 at about L3, roughly
00:06:12 --> 00:06:15 12 kilometres up inside the barrier.
00:06:15 --> 00:06:18 And it grew in place. Then the
00:06:18 --> 00:06:20 electrons spread out from it, both inward
00:06:20 --> 00:06:23 towards Earth and outward. That's
00:06:23 --> 00:06:25 the bus in the middle of the footpath. They
00:06:25 --> 00:06:26 were made there.
00:06:27 --> 00:06:28 Anna: So what's the engine?
00:06:29 --> 00:06:31 The team points to chorus waves.
00:06:32 --> 00:06:34 These are natural radio waves in the
00:06:34 --> 00:06:37 magnetosphere at audio frequencies.
00:06:37 --> 00:06:39 Feed them into a speaker and they sound
00:06:40 --> 00:06:42 remarkably like birds at dawn. But
00:06:43 --> 00:06:44 which is where the name comes from.
00:06:45 --> 00:06:48 Avery: Porous waves are generated during storms
00:06:48 --> 00:06:51 by lower energy electrons injected from the
00:06:51 --> 00:06:54 magnetotail and they can resonate with other
00:06:54 --> 00:06:56 electrons and push them to very high
00:06:56 --> 00:06:59 energies. Normally they can't operate
00:06:59 --> 00:07:02 where this happened because the dense plasma
00:07:02 --> 00:07:03 sphere fills that region.
00:07:03 --> 00:07:06 Anna: But in May 2024, two
00:07:06 --> 00:07:09 things lined up. The storm crushed
00:07:09 --> 00:07:11 the plasma sphere far closer to Earth than
00:07:11 --> 00:07:14 usual. And at the same time, a, uh,
00:07:14 --> 00:07:16 negative ionospheric storm drained
00:07:16 --> 00:07:19 electrons from the ionosphere 90 to
00:07:19 --> 00:07:22 500 kilometres up. That's the
00:07:22 --> 00:07:24 reservoir that normally refills the plasma
00:07:24 --> 00:07:27 sphere after a storm. With the reservoir low,
00:07:27 --> 00:07:30 the plasma sphere stayed shrunken for longer
00:07:30 --> 00:07:31 than usual.
00:07:31 --> 00:07:34 Avery: So for days, a region that's normally
00:07:34 --> 00:07:37 full of cold plasma was close to empty.
00:07:38 --> 00:07:40 Arase saw intense chorus waves there. At
00:07:40 --> 00:07:42 the same time the electrons were growing
00:07:43 --> 00:07:45 chorus waves where they shouldn't be,
00:07:45 --> 00:07:48 accelerating electrons where they shouldn't
00:07:48 --> 00:07:48 be.
00:07:48 --> 00:07:51 Anna: It's a chain. The sun compresses the
00:07:51 --> 00:07:54 magnetosphere, the plasmasphere gets crushed,
00:07:54 --> 00:07:57 the ionosphere can't refill it, the
00:07:57 --> 00:08:00 waves move in and the wall gets bypassed
00:08:00 --> 00:08:01 from the inside.
00:08:01 --> 00:08:04 Avery: Three honest caveats. First,
00:08:04 --> 00:08:07 this is one storm, a once in two
00:08:07 --> 00:08:10 decades event, and the paper is careful about
00:08:10 --> 00:08:13 that. Second, the authors say the
00:08:13 --> 00:08:15 observations are consistent with chorus
00:08:15 --> 00:08:18 driven acceleration. Waves and
00:08:18 --> 00:08:21 acceleration seen together in the same place
00:08:21 --> 00:08:23 is a strong case, but it isn't a direct
00:08:23 --> 00:08:24 proof of cause.
00:08:25 --> 00:08:27 Anna: And third, the breach itself
00:08:27 --> 00:08:30 isn't the new part. Low altitude
00:08:30 --> 00:08:32 satellites reported high energy electrons
00:08:32 --> 00:08:35 rising inside the barrier during the 2003
00:08:35 --> 00:08:38 Halloween storms. And earlier this year, a
00:08:38 --> 00:08:41 Chinese led team, Sun, Liu Zhong and
00:08:41 --> 00:08:44 colleagues combining the MSS1 satellite
00:08:44 --> 00:08:47 with Arase, reported that the barrier had
00:08:47 --> 00:08:49 been violated in May 2024.
00:08:50 --> 00:08:52 What this paper adds is the mechanism, the
00:08:52 --> 00:08:54 peak that grew in place.
00:08:55 --> 00:08:57 Avery: For spacecraft designers, the region inside
00:08:57 --> 00:09:00 the barrier has been treated as comparatively
00:09:00 --> 00:09:02 calm for these ultra relativistic
00:09:02 --> 00:09:05 electrons, anything that lives in or
00:09:05 --> 00:09:08 passes through it. Satellites in medium
00:09:08 --> 00:09:10 orbits. Spacecraft climbing out towards
00:09:10 --> 00:09:13 geostationary orbit or the moon may
00:09:13 --> 00:09:15 need margin for the rare storm that switches
00:09:15 --> 00:09:15 it on.
00:09:16 --> 00:09:18 Anna: It also completes a run we've been building
00:09:18 --> 00:09:21 on this show. In episode 192,
00:09:21 --> 00:09:24 the Super Flare, the Sun could produce in
00:09:24 --> 00:09:26 193 the radiation dose on a long
00:09:26 --> 00:09:29 haul flight. And a Fortnight ago in
00:09:29 --> 00:09:32 211 weather balloons sent up into a
00:09:32 --> 00:09:33 radiation storm.
00:09:33 --> 00:09:36 Same dial each time. This one adds
00:09:36 --> 00:09:39 a twist. A big storm doesn't just bring
00:09:39 --> 00:09:42 radiation in, it can rearrange the house,
00:09:42 --> 00:09:44 so the radiation is made inside.
00:09:45 --> 00:09:47 Avery: And timing matters here, too. Solar
00:09:47 --> 00:09:50 Cycle 25 is past its peak. Um, and we've been
00:09:50 --> 00:09:53 tracking the spotless days. But the 2003
00:09:53 --> 00:09:56 Halloween storms came well after solar cycle
00:09:56 --> 00:09:59 23 had peaked. The declining years still
00:09:59 --> 00:10:00 throw big punches,
00:10:00 --> 00:10:03 Anna: which is a fitting thought for tonight. Happy
00:10:03 --> 00:10:05 Halloween from the inside of the impenetrable
00:10:05 --> 00:10:06 barrier.
00:10:06 --> 00:10:09 Avery: One more fresh story before the recap, and
00:10:09 --> 00:10:11 it's a nice companion to Monday's lead on,
00:10:11 --> 00:10:14 um, the 10th of March this year, NASA's Fermi
00:10:14 --> 00:10:17 telescope caught a gamma ray burst, now
00:10:17 --> 00:10:17 called
00:10:17 --> 00:10:20 GRB260310A.
00:10:21 --> 00:10:24 Its gamma ray flash lasted about a minute,
00:10:24 --> 00:10:26 which made it a long burst, the kind made by
00:10:26 --> 00:10:29 a collapsing massive star. But the flash was
00:10:29 --> 00:10:30 feeble for its class.
00:10:31 --> 00:10:33 Anna: And then the afterglow refused to
00:10:33 --> 00:10:36 behave. Instead of fading from the start,
00:10:37 --> 00:10:39 the visible light rose slowly over
00:10:39 --> 00:10:42 several hours. The X rays faded,
00:10:42 --> 00:10:45 then, after about three weeks, brightened
00:10:45 --> 00:10:46 again for around a week.
00:10:47 --> 00:10:50 Avery: And the afterglow was spectacular. A
00:10:50 --> 00:10:53 team led by Johan Yang at the University of
00:10:53 --> 00:10:55 Rome Torvegata publishing in the
00:10:55 --> 00:10:58 Astrophysical Journal Letters, ranks its X
00:10:58 --> 00:11:01 ray and optical afterglows in the top 1%
00:11:01 --> 00:11:04 of all bursts, and its radio in the top
00:11:04 --> 00:11:06 five. The burst sits at a
00:11:06 --> 00:11:09 redshift of about 0.15,
00:11:09 --> 00:11:12 roughly 2 billion light years away. And a
00:11:12 --> 00:11:14 supernova of the kind that accompanies
00:11:14 --> 00:11:17 collapsing stars was confirmed underneath it.
00:11:18 --> 00:11:21 Anna: So a weak flash and a brilliant
00:11:21 --> 00:11:23 afterglow. How do you get both?
00:11:23 --> 00:11:26 Avery: Their answer is geometry. A
00:11:26 --> 00:11:28 burst's jet is like a torch beam.
00:11:29 --> 00:11:31 Look straight down it and the flash is
00:11:31 --> 00:11:34 blinding. Stand off to the side and you
00:11:34 --> 00:11:37 miss the flash. But as, uh, the jet slows,
00:11:37 --> 00:11:40 its light spreads to wider angles and the
00:11:40 --> 00:11:43 afterglow rises into view. That's the
00:11:43 --> 00:11:46 slow rise they saw. And they argue for a
00:11:46 --> 00:11:48 jet with two parts. A narrow, bright
00:11:48 --> 00:11:51 core inside a wider sheath. With the late
00:11:51 --> 00:11:54 X ray rebrightening, possibly the core
00:11:54 --> 00:11:55 swinging into view,
00:11:56 --> 00:11:58 Anna: they used Chandra time to rule out a
00:11:58 --> 00:12:01 neighbouring source contaminating the X rays.
00:12:01 --> 00:12:04 And their headline estimate is that someone
00:12:04 --> 00:12:06 looking straight down the core would have
00:12:06 --> 00:12:08 seen roughly a billion years of the sun's
00:12:08 --> 00:12:10 output packed into that beam.
00:12:11 --> 00:12:13 Avery: Caveats. The paper first appeared as a
00:12:13 --> 00:12:16 preprint in May, so it's five months old in
00:12:16 --> 00:12:18 that form, published in the Journal this
00:12:18 --> 00:12:21 month. And this burst has attracted at
00:12:21 --> 00:12:24 least four papers. One competing team
00:12:24 --> 00:12:27 weighs a slower debris laden jet seen
00:12:27 --> 00:12:29 nearly head on as an alternative. The
00:12:29 --> 00:12:31 geometry is argued, not settled,
00:12:32 --> 00:12:35 Anna: but there's a lovely lesson in it. On Monday
00:12:35 --> 00:12:37 we had a burst that looked like two different
00:12:37 --> 00:12:40 explosions today, one that looked
00:12:40 --> 00:12:43 faint and wasn't. Both are telling us the
00:12:43 --> 00:12:46 same thing. Our neat categories partly
00:12:46 --> 00:12:48 reflect where we happen to be standing.
00:12:48 --> 00:12:51 Avery: Okay, moving on. What's next?
00:12:51 --> 00:12:54 Anna: Now the week that was in the
00:12:54 --> 00:12:55 order it happened
00:12:56 --> 00:12:58 Avery: Monday led with GRB
00:12:58 --> 00:13:00 160425A in
00:13:00 --> 00:13:02 April 2016,
00:13:03 --> 00:13:06 Swift caught a sharp flash under two seconds
00:13:06 --> 00:13:08 long, then more than four minutes of
00:13:08 --> 00:13:11 silence, then a second Messier
00:13:11 --> 00:13:14 episode lasting nearly a minute from the
00:13:14 --> 00:13:17 same patch of sky. Short bursts
00:13:17 --> 00:13:20 mean mergers, long ones mean
00:13:20 --> 00:13:23 collapsing stars, and this one looked
00:13:23 --> 00:13:25 like both. The paper in Nature
00:13:25 --> 00:13:28 Astronomy keeps the mechanism open and um,
00:13:28 --> 00:13:29 that's how we left it.
00:13:29 --> 00:13:32 Anna: Monday also brought a black hole disc
00:13:32 --> 00:13:35 in Maxi J0637
00:13:36 --> 00:13:38 that puffs up and shades itself at at only
00:13:38 --> 00:13:41 about a fifth of its maximum feeding rate,
00:13:41 --> 00:13:44 a record deuterium rich methane measurement
00:13:44 --> 00:13:46 from Interstellar Comet 3I Atlas
00:13:48 --> 00:13:51 and NASA's Psyche thrusting almost
00:13:51 --> 00:13:54 continuously toward its 2029 arrival.
00:13:54 --> 00:13:57 Avery: Tuesday's lead solved a puzzle in Orion.
00:13:58 --> 00:14:00 The discs around the young stars in the Orion
00:14:00 --> 00:14:02 Nebula are being eroded so fast they
00:14:02 --> 00:14:05 shouldn't still exist, and the nebulous shell
00:14:05 --> 00:14:08 looks too young as well. Wilhelm Trani
00:14:08 --> 00:14:11 and Portahese Zwart showed that both make
00:14:11 --> 00:14:14 sense if the massive star at the centre Theta
00:14:14 --> 00:14:16 one or Rionis the C, recently formed in a
00:14:16 --> 00:14:19 stellar merger, so its fierce ultraviolet
00:14:19 --> 00:14:21 switched on later than the region's age
00:14:21 --> 00:14:23 implies. There's a clean an
00:14:23 --> 00:14:26 inner companion on a 61 and a half day orbit.
00:14:26 --> 00:14:29 Anna: Tuesday also had a white dwarf with a
00:14:29 --> 00:14:32 double gas disc hinting at two hidden
00:14:32 --> 00:14:35 bodies, and a Yale study finding that giant
00:14:35 --> 00:14:37 impacts can let rocky planets keep their
00:14:37 --> 00:14:38 primordial atmospheres.
00:14:39 --> 00:14:42 Avery: Wednesday was Rubin's first dwarf
00:14:42 --> 00:14:44 planet candidate 2026
00:14:44 --> 00:14:47 ED138. It's about
00:14:47 --> 00:14:49 46 astronomical units away,
00:14:49 --> 00:14:52 somewhere between 600 and 1
00:14:52 --> 00:14:55 kilometres across, and it hit for years
00:14:55 --> 00:14:58 against the crowded Milky Way at a
00:14:58 --> 00:15:01 declination of -43, a properly
00:15:01 --> 00:15:03 southern object. Once it was found, it
00:15:03 --> 00:15:06 turned up in older dark energy camera images
00:15:06 --> 00:15:07 going back to 2016.
00:15:08 --> 00:15:09 Anna: Also Wednesday,
00:15:09 --> 00:15:12 TOI561B, a
00:15:12 --> 00:15:15 lava world reflecting most of the light that
00:15:15 --> 00:15:17 hits it, with University of Sydney co
00:15:17 --> 00:15:20 authors and HERA seeing Didymos
00:15:20 --> 00:15:23 and Dimorphos as two separate points for
00:15:23 --> 00:15:24 the first time.
00:15:24 --> 00:15:27 Avery: Thursday led with Betelgeuse radio and
00:15:27 --> 00:15:30 millimetre images from the VLA and ALMA
00:15:30 --> 00:15:33 gathered over Five years show the star's
00:15:33 --> 00:15:35 shape stretching in step with the orbit of
00:15:35 --> 00:15:37 its small companion Sahuara.
00:15:38 --> 00:15:40 Betelgeuse is being pulled out of round by
00:15:40 --> 00:15:43 something we can barely see. Saguara
00:15:43 --> 00:15:45 comes back out from behind the star in late
00:15:45 --> 00:15:46 2027.
00:15:47 --> 00:15:49 Anna: Thursday also covered radiation
00:15:49 --> 00:15:51 detectors flown on Artemis 1.
00:15:52 --> 00:15:55 A Cambridge study finding comets were a
00:15:55 --> 00:15:58 poor delivery route for hydrogen cyanide to
00:15:58 --> 00:16:01 early Earth, but about five times better for
00:16:01 --> 00:16:03 Mars and Virgin Galactic's new
00:16:03 --> 00:16:05 space plane Aperon.
00:16:06 --> 00:16:08 Avery: And Friday LED with Tegaza
00:16:08 --> 00:16:11 001, a uh, Martian meteorite from the
00:16:11 --> 00:16:14 Zaharov. At least 4.1 billion
00:16:14 --> 00:16:15 years old.
00:16:15 --> 00:16:17 One of the oldest pieces of Mars we have
00:16:17 --> 00:16:20 published in Science. We noted
00:16:20 --> 00:16:23 the age was first shown at a conference in
00:16:23 --> 00:16:25 July. Friday also brought Voyager
00:16:25 --> 00:16:28 1's two days of silence in mid October and
00:16:28 --> 00:16:31 um, the Beta Pictoris cat's tail, which looks
00:16:31 --> 00:16:32 like the wreckage of a collision between
00:16:32 --> 00:16:35 bodies the size of charon or
00:16:35 --> 00:16:35 makemake.
00:16:36 --> 00:16:38 Anna: Three threads to close
00:16:39 --> 00:16:42 Swift. NASA ended operations on
00:16:42 --> 00:16:44 20 October at about
00:16:44 --> 00:16:47 275 kilometres and re entry
00:16:47 --> 00:16:50 is expected within weeks as we record it
00:16:50 --> 00:16:52 hasn't come down. Will tell you when it does.
00:16:52 --> 00:16:55 Avery: Voyager 1 reaches one light day
00:16:55 --> 00:16:58 from Earth on 18 November, the first
00:16:58 --> 00:17:00 object ever to get that far.
00:17:01 --> 00:17:03 And Starship Flight 15 is targeted for
00:17:03 --> 00:17:06 November with SpaceX saying it uh, will try
00:17:06 --> 00:17:08 to catch both stages with the tower
00:17:09 --> 00:17:11 targeted. Not scheduled.
00:17:12 --> 00:17:13 Anna: Next up, Skywatch,
00:17:14 --> 00:17:16 Avery: let's look up first a uh,
00:17:16 --> 00:17:19 Halloween bonus. Halloween descends
00:17:19 --> 00:17:22 from Samhain, a festival that falls on a
00:17:22 --> 00:17:25 cross quarter day halfway between an equinox
00:17:25 --> 00:17:27 and a solstice. But the true
00:17:27 --> 00:17:30 astronomical midpoint, when the sun is
00:17:30 --> 00:17:32 exactly halfway along the sky from the
00:17:32 --> 00:17:34 September equinox to the December solstice,
00:17:35 --> 00:17:37 doesn't arrive until the 7th of November at a
00:17:37 --> 00:17:39 quarter to seven in the evening UTC.
00:17:40 --> 00:17:43 So astronomically, Halloween is a week
00:17:43 --> 00:17:43 early.
00:17:44 --> 00:17:46 Anna: And in the southern hemisphere that same
00:17:46 --> 00:17:49 moment is the midpoint between spring
00:17:49 --> 00:17:51 and summer, not autumn and winter.
00:17:52 --> 00:17:54 One instant, two seasons
00:17:55 --> 00:17:56 depending where you stand.
00:17:57 --> 00:18:00 Avery: The best show this week is before dawn and it
00:18:00 --> 00:18:02 strongly favours the north. Mars and
00:18:02 --> 00:18:05 Jupiter are closing in Leo with the star
00:18:05 --> 00:18:07 Regulus just beside them. They're under
00:18:07 --> 00:18:10 6 degrees apart on Sunday, about 3
00:18:10 --> 00:18:13 degrees by the 8th and just over 1 degree
00:18:13 --> 00:18:15 on the 16th of November
00:18:15 --> 00:18:18 Anna: from Los Angeles at nautical dawn on
00:18:18 --> 00:18:21 Sunday, Jupiter stands 60 degrees
00:18:21 --> 00:18:23 up and Mars 65
00:18:24 --> 00:18:26 from New York 56 and 61
00:18:27 --> 00:18:30 from London, about 50 from
00:18:30 --> 00:18:32 Sydney. Both are only about 25 degrees
00:18:32 --> 00:18:35 up low in the northeast, still
00:18:35 --> 00:18:38 worth it. But the north gets the better view
00:18:38 --> 00:18:41 Avery: and the Moon joins them. Last quarter is
00:18:41 --> 00:18:44 Monday the 2nd at 7:28 in the morning
00:18:44 --> 00:18:46 Sydney time, which is late Sunday evening
00:18:46 --> 00:18:49 utc. Over the next two mornings, the
00:18:49 --> 00:18:52 Moon passes about a degree from Mars, about
00:18:52 --> 00:18:54 half a degree from Jupiter, then close to
00:18:54 --> 00:18:57 Regulus. Exact distances depend on
00:18:57 --> 00:19:00 where you are, so look on the mornings of the
00:19:00 --> 00:19:01 second and third.
00:19:01 --> 00:19:04 Anna: A reminder for North American listeners
00:19:04 --> 00:19:07 Clocks fall back on Sunday morning,
00:19:07 --> 00:19:10 the 1st of November. That makes
00:19:10 --> 00:19:13 dawn earlier on the clock. Nautical
00:19:13 --> 00:19:15 dawn on Sunday is about 5:17
00:19:15 --> 00:19:18 in Los Angeles and 5:25 in
00:19:18 --> 00:19:20 New York Standard Time.
00:19:20 --> 00:19:22 Avery: The evening belongs to the South.
00:19:23 --> 00:19:25 Saturn is the only bright planet after
00:19:25 --> 00:19:28 sunset. Half an hour after sunset tonight,
00:19:28 --> 00:19:31 it's 35 degrees up from Sydney against
00:19:31 --> 00:19:34 21 from Los Angeles, 18 from New
00:19:34 --> 00:19:36 York and 11 from London.
00:19:37 --> 00:19:39 Mercury has dropped back into the twilight,
00:19:39 --> 00:19:42 and it's gone for now. Venus
00:19:42 --> 00:19:44 has passed between us and the sun and will
00:19:44 --> 00:19:46 climb into the dawn sky over the coming
00:19:46 --> 00:19:49 weeks. But it isn't clear of the glare yet,
00:19:49 --> 00:19:52 Anna: and given today's lead, the sun
00:19:52 --> 00:19:54 is still active and space weather
00:19:54 --> 00:19:57 forecasters have flagged the chance of minor
00:19:57 --> 00:20:00 geomagnetic storming this weekend. If you're
00:20:00 --> 00:20:03 at high latitude north or south, check your
00:20:03 --> 00:20:06 local aurora alerts before you write off the
00:20:06 --> 00:20:06 night.
00:20:07 --> 00:20:10 Avery: And our standing reminder never look
00:20:10 --> 00:20:12 at the sun directly or through any optics
00:20:12 --> 00:20:15 without proper protection. For solar viewing,
00:20:15 --> 00:20:18 use only eclipse glasses or filters
00:20:18 --> 00:20:20 certified to the international safety
00:20:20 --> 00:20:21 standard ISO
00:20:21 --> 00:20:24 123122 from a
00:20:24 --> 00:20:27 reputable supplier and check them for damage
00:20:27 --> 00:20:27 before every use.
00:20:28 --> 00:20:31 Anna: That's the weekend wrap electrons
00:20:31 --> 00:20:33 made on the wrong side of Earth's
00:20:33 --> 00:20:36 impenetrable barrier, a gamma ray burst
00:20:36 --> 00:20:39 that only looked weak, and a week that
00:20:39 --> 00:20:41 ran from Orion to Betelgeuse to
00:20:42 --> 00:20:44 the oldest piece of Mars.
00:20:45 --> 00:20:47 Avery: Show notes, sources and links to every
00:20:47 --> 00:20:48 paper are at
00:20:48 --> 00:20:50 astronomydaily.IO
00:20:51 --> 00:20:54 Questions or story ideas use the contact
00:20:54 --> 00:20:56 form there. Some of our best segments have
00:20:56 --> 00:20:59 started with a listener's question and you'll
00:20:59 --> 00:21:02 find us on social media. Astrodaily Podcast
00:21:02 --> 00:21:05 Anna: Happy Halloween and Clear asgive. I'm
00:21:05 --> 00:21:05 Anna.
00:21:06 --> 00:21:07 Avery: And I'm Avery.
00:21:07 --> 00:21:08 Anna: See you Monday.