A hot Jupiter called TOI-2535 b has become the first planet around a single star seen to stop transiting, tipped out of line by an unseen neighbour. Plus: why Uranus and Neptune have scrambled magnetic fields, MeerKAT measuring how cosmic hydrogen clusters, Euclid's first big data release, ESCAPADE heading for Mars, Starship Flight 15's double-catch attempt, the 2026 ozone hole, and a both-hemispheres sky with Mars and Jupiter 1.2 degrees apart. The planet that stopped transiting. TOI-2535 b, an 8.24-day hot Jupiter ~1,000 light-years away, ran up to ~6 hours early or late and its transits shortened and faded over seven years of TESS data until they vanished in 2026. A hidden companion of at least Saturn mass, likely in resonance on a tilted orbit, is making both orbits precess. Transits should return in 30–50 years. Yee, Petigura et al., The Astrophysical Journal Letters, 9 Nov 2026. Ice giants' scrambled magnetic fields. Dynamo models with electrical conductivity rising with depth reproduce Uranus- and Neptune-like fields, and suggest their tilt could shift by tens of degrees within decades. Aurora observations could test for change since Voyager 2. Yan et al., Communications Physics. MeerKLASS hears the cosmic web. Running MeerKAT's 64 dishes as independent telescopes, the MeerKLASS collaboration detected the 21-cm hydrogen power spectrum on cosmological scales at z = 0.42 over ~236 square degrees, signal-to-noise 6.2. MNRAS. Euclid DR1-Foundation. ~1,900 square degrees (about 1,400 in the southern sky), ~1.8 PB of images, catalogues and spectra. Weak-lensing and clustering products follow in mid-2027. Quick hits. ESCAPADE Blue and Gold complete powered Earth flybys, Mars arrival Sept 2027; Starship Flight 15 targeted NET 13 Nov 22:45 UTC; 2026 Antarctic ozone hole seventh largest in 48 years, recovery on track. Skywatch. Mars–Jupiter 1.19° on 16 Nov (pre-dawn, north-favoured); Venus 1.2° from Spica, a 10%-lit crescent; Saturn high in southern evenings; Leonids peak 17–18 Nov; first quarter 17 Nov, full Moon 24 Nov. Sources · UCLA Newsroom — First known 'disappearing planet' — https://newsroom.ucla.edu/releases/first-known-disappearing-planet-neighbor-wobble-like-top · Yee et al., ApJL 1011 L60 — https://iopscience.iop.org/article/10.3847/2041-8213/aeb4a4 · arXiv 2611.13343 — https://arxiv.org/abs/2611.13343 · Yan et al., Communications Physics — https://www.nature.com/articles/s42005-026-02841-y · UT Austin Jackson School release — https://www.jsg.utexas.edu/news/2026/11/wacky-magnetic-fields-of-ice-giants-explained/ · University of Portsmouth — MeerKLASS — https://www.port.ac.uk/news-events-and-blogs/news/breakthrough-cosmic-hydrogen-measurement-could-transform-our-view-of-the-universe · MNRAS stag1911 (DOI) — https://doi.org/10.1093/mnras/stag1911 · Caltech/IPAC — Euclid DR1 — https://euclid.caltech.edu/page/euclid-dr1 · ESA — DR1 timeline — https://www.cosmos.esa.int/web/euclid/dr1-timeline · Berkeley News — ESCAPADE — http://news.berkeley.edu/2026/11/09/berkeleys-escapade-spacecraft-say-goodbye-to-earth-next-stop-mars/ · NextSpaceflight — Starship Flight 15 — https://nextspaceflight.com/launches/details/8403/
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This episode includes AI-generated content.
00:00:00 --> 00:00:02 Anna: Hello, everyone. For seven years,
00:00:03 --> 00:00:06 a giant planet crossed the face of its star
00:00:06 --> 00:00:09 every eight days. Astronomers could set
00:00:09 --> 00:00:12 their watches by it. Then this
00:00:12 --> 00:00:14 March, it simply didn't turn up.
00:00:14 --> 00:00:17 Avery: It hasn't been destroyed and it hasn't
00:00:17 --> 00:00:20 fallen into its star. Something
00:00:20 --> 00:00:23 we can't see has tipped its orbit
00:00:23 --> 00:00:25 and it slid out of line with us or while we
00:00:25 --> 00:00:26 were watching.
00:00:27 --> 00:00:29 Anna: That's our lead today. We also have
00:00:29 --> 00:00:32 a new way to explain the scrambled magnetic
00:00:32 --> 00:00:35 fields of Uranus and Neptune. A, uh, South
00:00:35 --> 00:00:38 African telescope hearing the clustering of
00:00:38 --> 00:00:41 hydrogen across billions of years. And
00:00:41 --> 00:00:43 Euclid opening its first big data release
00:00:43 --> 00:00:44 to the whole world.
00:00:45 --> 00:00:48 Avery: Plus a twin spacecraft. Goodbye.
00:00:48 --> 00:00:51 A starship double catch attempt. And a sky
00:00:51 --> 00:00:53 with Mars and Jupiter closing to just over a
00:00:53 --> 00:00:56 degree. This is Astronomy AstroDailyPod.
00:00:56 --> 00:00:57 I'm Avery.
00:00:57 --> 00:01:00 Anna: And I'm Anna. Let's get into it.
00:01:00 --> 00:01:02 The planet is called
00:01:02 --> 00:01:04 TOI2535B
00:01:05 --> 00:01:07 and it's a hot Jupiter, a gas
00:01:07 --> 00:01:10 giant about the size of Jupiter whipping
00:01:10 --> 00:01:12 around its star once every eight and a
00:01:12 --> 00:01:15 quarter days. For comparison,
00:01:15 --> 00:01:18 Mercury takes 88 days to go around the Sun.
00:01:18 --> 00:01:21 The system is roughly 1 light years
00:01:21 --> 00:01:22 away.
00:01:22 --> 00:01:25 Avery: And it was found the usual way by NASA's Tess
00:01:25 --> 00:01:28 satellite, which watches for the tiny dip in
00:01:28 --> 00:01:30 starlight when a planet passes in front of
00:01:30 --> 00:01:32 its star. A, uh, transit,
00:01:32 --> 00:01:35 Anna: right. TESS kept coming back to this patch of
00:01:35 --> 00:01:38 sky between April 2019 and March
00:01:38 --> 00:01:41 2026. So the team had seven years of
00:01:41 --> 00:01:43 transits to work with. And from the start,
00:01:43 --> 00:01:46 this planet refused to keep time. Transits
00:01:46 --> 00:01:48 that should have been as regular as a train
00:01:48 --> 00:01:51 timetable came hours early or
00:01:51 --> 00:01:54 hours late by up to about six hours. Ide.
00:01:55 --> 00:01:57 Avery: That alone tells you something is pulling on
00:01:58 --> 00:02:01 Anna: does. But the bigger clue was the
00:02:01 --> 00:02:04 shape of the transits. Year by year
00:02:04 --> 00:02:06 they got shorter and they got shallower.
00:02:07 --> 00:02:09 The planet was crossing less and less of the
00:02:09 --> 00:02:12 star's face, skimming closer to the edge
00:02:12 --> 00:02:15 each time. And then in tess's
00:02:15 --> 00:02:17 observations this year, there was nothing at
00:02:17 --> 00:02:19 all. The dips were gone.
00:02:20 --> 00:02:22 Avery: So how does a planet just stop crossing its
00:02:22 --> 00:02:25 star? It's still there, presumably.
00:02:25 --> 00:02:28 Anna: It's still there, still going round every
00:02:28 --> 00:02:31 eight days. What changed is the tilt
00:02:31 --> 00:02:34 of its orbit. A transit means a lucky
00:02:34 --> 00:02:37 alignment. The orbit has to be almost exactly
00:02:37 --> 00:02:40 edge on to us. Tip that orbit by a
00:02:40 --> 00:02:43 few degrees and the planet sails above or
00:02:43 --> 00:02:45 below the star from our point of view and we
00:02:45 --> 00:02:46 see nothing.
00:02:46 --> 00:02:49 Avery: And co author Eric Pettigura at UCLA
00:02:49 --> 00:02:52 has a lovely way of explaining that. Which is
00:02:52 --> 00:02:52 the moon?
00:02:53 --> 00:02:55 Anna: He does. If the moon's orbit sat
00:02:55 --> 00:02:58 in exactly the same plane as Earth's orbit
00:02:58 --> 00:03:00 around the Sun. We'd get a solar eclipse
00:03:00 --> 00:03:03 every single month. We don't, because the
00:03:03 --> 00:03:05 Moon's orbit is tilted by about 5 degrees.
00:03:06 --> 00:03:08 Eclipses only happen when the geometry lines
00:03:08 --> 00:03:11 up. TOI 2535B
00:03:11 --> 00:03:14 is the same idea, except its tilt isn't
00:03:14 --> 00:03:17 fixed. It's changing fast enough that we
00:03:17 --> 00:03:19 watched it go from transiting to not
00:03:19 --> 00:03:21 transiting within a single survey.
00:03:21 --> 00:03:24 Avery: Samuel Yee, the corresponding author, put it
00:03:24 --> 00:03:27 pretty simply. The orbit is tilting so
00:03:27 --> 00:03:30 quickly that the transit disappeared while we
00:03:30 --> 00:03:31 were watching.
00:03:31 --> 00:03:34 Anna: So what's doing the tilting? The team
00:03:34 --> 00:03:37 led by Samuel Yee and Eric Pettigrewa at
00:03:37 --> 00:03:40 UCLA modelled those timing shifts and the
00:03:40 --> 00:03:43 changing transit shapes together. The
00:03:43 --> 00:03:45 best explanation is a second planet that we
00:03:45 --> 00:03:48 have never seen, at least as massive as
00:03:48 --> 00:03:51 Saturn, on an orbit tilted relative to
00:03:51 --> 00:03:54 TOI2535BS and very
00:03:54 --> 00:03:56 likely locked in what's called a mean motion
00:03:56 --> 00:03:57 resonance with it.
00:03:58 --> 00:04:00 Avery: Meaning their orbital periods are in a simple
00:04:00 --> 00:04:03 whole number ratio. So they keep meeting in
00:04:03 --> 00:04:06 the same places. And the tugs add up.
00:04:06 --> 00:04:09 Anna: Exactly. And because the two orbits are
00:04:09 --> 00:04:11 tilted against each other, each planet
00:04:11 --> 00:04:14 drags on the other's orbital plane. Both
00:04:14 --> 00:04:17 planes wobble like a spinning top that's
00:04:17 --> 00:04:20 slowing down and starting to precess. The
00:04:20 --> 00:04:22 team estimates that wobble takes something
00:04:22 --> 00:04:25 like 30 to 50 years to come round,
00:04:25 --> 00:04:26 Avery: which means it comes back.
00:04:27 --> 00:04:29 Anna: It should. They expect TOI
00:04:29 --> 00:04:32 2535B to start transiting again
00:04:32 --> 00:04:34 sometime in the next 30 to 50 years.
00:04:35 --> 00:04:37 And here's the part I love. As this planet
00:04:37 --> 00:04:40 tilts out of you, its hidden neighbour may
00:04:40 --> 00:04:42 tilt into view and could start transiting
00:04:42 --> 00:04:43 sooner than that.
00:04:44 --> 00:04:46 Avery: Regular listeners might be getting deja vu
00:04:46 --> 00:04:49 because we've had a planet like this before.
00:04:50 --> 00:04:52 Anna: Back in episode 199 in September,
00:04:53 --> 00:04:56 POI 1355B, the
00:04:56 --> 00:04:58 eccentric super Jupiter around a fast
00:04:58 --> 00:05:01 spinning hot star. Its orbit is
00:05:01 --> 00:05:03 precessing too, and its transits are
00:05:03 --> 00:05:06 predicted to end around 2033. But
00:05:06 --> 00:05:08 there the culprit is the star itself,
00:05:08 --> 00:05:10 flattened by its own Rapid spin.
00:05:11 --> 00:05:14 POI2535B is
00:05:14 --> 00:05:16 being tipped by another planet. And it isn't
00:05:16 --> 00:05:18 a prediction. It's already happened.
00:05:19 --> 00:05:22 Avery: Okay, so the neighbour is inferred.
00:05:22 --> 00:05:24 Nobody has actually seen it.
00:05:24 --> 00:05:27 Anna: That's the first caveat, and it's an
00:05:27 --> 00:05:29 important one. The companion is inferred
00:05:29 --> 00:05:32 from what it does to TOI 2535B,
00:05:33 --> 00:05:36 not detected directly. The resonance is
00:05:36 --> 00:05:38 described as in or near
00:05:39 --> 00:05:41 not nailed down. And the paper is careful to
00:05:41 --> 00:05:44 say the perturber is likely Saturn mass
00:05:44 --> 00:05:47 or greater, which is a floor, not a
00:05:47 --> 00:05:47 measurement.
00:05:48 --> 00:05:49 Avery: Is there a way to check?
00:05:49 --> 00:05:52 Anna: Yes. And it doesn't need transits. The
00:05:52 --> 00:05:55 planets still tug the star back and forth. So
00:05:55 --> 00:05:58 precise radial velocity measurements watching
00:05:58 --> 00:06:00 the star's spectrum shift can follow the
00:06:00 --> 00:06:03 system while it's hidden. That's the obvious
00:06:03 --> 00:06:05 next step. And it could measure the companion
00:06:05 --> 00:06:06 directly.
00:06:06 --> 00:06:08 Avery: And to be precise about the record,
00:06:09 --> 00:06:11 Anna: the paper calls it the first confirmed
00:06:11 --> 00:06:14 planet orbiting a single star whose
00:06:14 --> 00:06:16 transits have been directly observed to
00:06:16 --> 00:06:19 disappear. Single star is doing
00:06:19 --> 00:06:22 real work there. Planets that orbit pairs of
00:06:22 --> 00:06:25 stars, circumbinary planets have had
00:06:25 --> 00:06:27 transits come and go before because two
00:06:27 --> 00:06:30 stars make orbital planes precess very
00:06:30 --> 00:06:33 readily. This is the first time a planet
00:06:33 --> 00:06:35 around a lone star has done it in front of
00:06:35 --> 00:06:35 us.
00:06:36 --> 00:06:39 Avery: There's also a method lesson in here, isn't
00:06:39 --> 00:06:39 there?
00:06:39 --> 00:06:42 Anna: There is. The authors point out that four
00:06:42 --> 00:06:45 years of test data alone would not have
00:06:45 --> 00:06:47 securely established the change in transit
00:06:47 --> 00:06:50 duration it took seven. That's a
00:06:50 --> 00:06:53 nice argument for long running surveys. Some
00:06:53 --> 00:06:55 of the most interesting things in the sky
00:06:55 --> 00:06:57 only reveal themselves if you keep looking.
00:06:58 --> 00:07:00 Avery: And it raises an uncomfortable thought about
00:07:00 --> 00:07:03 all the planets transit surveys never saw
00:07:03 --> 00:07:06 Anna: it does. Any planet in a
00:07:06 --> 00:07:09 system like this spends part of its cycle out
00:07:09 --> 00:07:12 of transit. So some systems we
00:07:12 --> 00:07:15 think have one transiting planet may have
00:07:15 --> 00:07:17 neighbours we're simply catching at the wrong
00:07:17 --> 00:07:19 moment. And some stars we think have none
00:07:20 --> 00:07:22 may have planets that just aren't lined up
00:07:22 --> 00:07:22 this decade.
00:07:23 --> 00:07:26 Avery: And how did it get so close to its star in
00:07:26 --> 00:07:26 the first place?
00:07:27 --> 00:07:29 Anna: That's the formation puzzle. Hot
00:07:29 --> 00:07:32 Jupiters probably didn't form where they are.
00:07:32 --> 00:07:35 It's too hot that close in. One idea
00:07:35 --> 00:07:38 is that they're flung inward violently onto
00:07:38 --> 00:07:40 stretched orbits and then tidally pulled in.
00:07:41 --> 00:07:43 That route tends to leave a hot Jupiter alone
00:07:43 --> 00:07:46 because anything nearby gets scattered.
00:07:47 --> 00:07:49 TOI2535B has a
00:07:49 --> 00:07:52 close massive neighbour. So Yi's reading
00:07:52 --> 00:07:55 is that it probably spiralled in gently with
00:07:55 --> 00:07:58 its sibling rather than being thrown a rarer
00:07:58 --> 00:08:00 pathway. If that's right. But that's the
00:08:00 --> 00:08:02 team's interpretation, not something this
00:08:02 --> 00:08:03 paper proves.
00:08:03 --> 00:08:06 Avery: The paper itself was published in the
00:08:06 --> 00:08:08 Astrophysical Journal letters on Monday
00:08:08 --> 00:08:09 9th November.
00:08:10 --> 00:08:12 Anna: And there's a strong southern thread in the
00:08:12 --> 00:08:15 team too. The ground based confirmation
00:08:15 --> 00:08:17 drew on co authors at Chilean institutions
00:08:18 --> 00:08:20 including Raphael Brahm and Andres
00:08:20 --> 00:08:23 Jordan and on high resolution imaging
00:08:23 --> 00:08:26 from the SOAR telescope on Cerro Petrone in
00:08:26 --> 00:08:28 Chile alongside the
00:08:28 --> 00:08:31 Wyn 3.5 metre telescope
00:08:31 --> 00:08:33 at Kitt Peak in Arizona.
00:08:34 --> 00:08:37 A planet that vanished pinned
00:08:37 --> 00:08:38 down from both hemispheres
00:08:39 --> 00:08:41 Avery: When Voyager 2 flew past Uranus in
00:08:41 --> 00:08:44 1986 and Neptune in 1989,
00:08:45 --> 00:08:47 it found something nobody expected. Earth,
00:08:47 --> 00:08:50 uh, Jupiter and Saturn have magnetic fields
00:08:50 --> 00:08:53 that look roughly like a bar magnet lined
00:08:53 --> 00:08:55 up fairly closely with the spin axis.
00:08:56 --> 00:08:59 Uranus and Neptune don't. Their fields are
00:08:59 --> 00:09:02 tilted by something like 50 to 60 degrees,
00:09:02 --> 00:09:05 offset from the planet's centre and lumpy
00:09:05 --> 00:09:07 with a lot of power outside the simple north
00:09:08 --> 00:09:08 south pattern.
00:09:09 --> 00:09:12 Anna: And we've had exactly two flybys worth of
00:09:12 --> 00:09:14 data to explain that with ever,
00:09:14 --> 00:09:17 Avery: which is why it's still a 40 year old
00:09:17 --> 00:09:20 puzzle. A new study led by Qi Yan at the
00:09:20 --> 00:09:22 University of Texas at Austin, published in
00:09:22 --> 00:09:25 Communications Physics, tries a specific
00:09:25 --> 00:09:27 explanation using computer models of the
00:09:27 --> 00:09:30 planet's dynamosthe churning, electrically
00:09:30 --> 00:09:32 conducting fluid layers that generate the
00:09:32 --> 00:09:32 fields.
00:09:33 --> 00:09:35 Avery: What's the key ingredient?
00:09:35 --> 00:09:38 Avery: Electrical conductivity that increases with
00:09:38 --> 00:09:40 depth. Deep inside the ice giants, pressures
00:09:40 --> 00:09:43 and temperatures are so extreme that water
00:09:43 --> 00:09:46 molecules break apart into ions. So the
00:09:46 --> 00:09:48 material conducts better and better the
00:09:48 --> 00:09:50 deeper you go. When the team built that
00:09:50 --> 00:09:53 gradient into their dynamo models, the models
00:09:53 --> 00:09:55 produce fields that look like Uranus and
00:09:55 --> 00:09:57 Neptune. Not dipole dominated, not
00:09:57 --> 00:10:00 lined up with the spin axis and with the same
00:10:00 --> 00:10:02 characteristic structure in the magnetic
00:10:02 --> 00:10:04 power spectrum that Voyager measured.
00:10:04 --> 00:10:06 Anna: And there's a twist that makes this more than
00:10:06 --> 00:10:08 a modelling exercise.
00:10:08 --> 00:10:11 Avery: There is these models produce fields that
00:10:11 --> 00:10:14 change quickly. The authors find the magnetic
00:10:14 --> 00:10:16 tilt could shift by tens of degrees within
00:10:16 --> 00:10:19 decades. And it has now been four decades
00:10:19 --> 00:10:20 since Voyager 2.
00:10:20 --> 00:10:23 Anna: So the field we measured might not be
00:10:23 --> 00:10:25 the field that's there today.
00:10:25 --> 00:10:28 Avery: That's the implication and it's testable.
00:10:28 --> 00:10:31 The researchers point to auroras. Where a
00:10:31 --> 00:10:34 planet's auroras appear depends on where its
00:10:34 --> 00:10:36 magnetic poles are. So watching Uranus's
00:10:36 --> 00:10:39 auroras today with Hubble or Webb could tell
00:10:39 --> 00:10:42 us whether the field has moved since 1986.
00:10:43 --> 00:10:45 And the real test would be the proposed
00:10:45 --> 00:10:47 Uranus Orbiter and probe, which would map the
00:10:47 --> 00:10:50 field properly over time rather than in one
00:10:50 --> 00:10:51 pass.
00:10:51 --> 00:10:52 Anna: Caveats.
00:10:53 --> 00:10:55 Avery: Two main ones. This is a simulation
00:10:55 --> 00:10:58 result. It shows conductivity structure is
00:10:58 --> 00:11:01 a plausible pathway to these fields. Not
00:11:01 --> 00:11:04 that it's the answer. Earlier ideas,
00:11:04 --> 00:11:07 like a, uh, thin dynamo shell sitting over a
00:11:07 --> 00:11:09 stable layer, or ices separating out
00:11:09 --> 00:11:11 inside the planets, are still in play.
00:11:12 --> 00:11:15 And the observations it's matched against are
00:11:15 --> 00:11:17 those single snapshots from the 1980s.
00:11:18 --> 00:11:20 That's exactly why the prediction of change
00:11:20 --> 00:11:22 is so useful. It gives the next mission
00:11:22 --> 00:11:24 something specific to look for
00:11:24 --> 00:11:25 Anna: next.
00:11:25 --> 00:11:27 A result a decade in the making from the
00:11:27 --> 00:11:30 Meerkat radio telescope in South Africa's
00:11:30 --> 00:11:32 Cairo, the Mir Klaas collaboration
00:11:33 --> 00:11:35 has measured how neutral hydrogen clusters on
00:11:35 --> 00:11:38 cosmological scales using a technique called
00:11:38 --> 00:11:40 21 centimetre intensity mapping.
00:11:41 --> 00:11:43 Avery: Remind us what intensity mapping is.
00:11:44 --> 00:11:47 Anna: Neutral hydrogen gives off a faint radio
00:11:47 --> 00:11:49 signal at a wavelength of 21 centimetres.
00:11:50 --> 00:11:52 Normally you'd detect galaxies one at a time.
00:11:52 --> 00:11:55 Intensity mapping doesn't bother. It measures
00:11:55 --> 00:11:58 the combined globe of hydrogen from many
00:11:58 --> 00:12:00 galaxies you can't individually see across
00:12:00 --> 00:12:03 big patches of sky and builds a three
00:12:03 --> 00:12:05 dimensional map from it. Because the
00:12:05 --> 00:12:07 universe's expansion stretches that 21
00:12:07 --> 00:12:10 centimetre line, the observed frequency tells
00:12:10 --> 00:12:10 you the distance.
00:12:11 --> 00:12:13 Avery: And the hard part is everything else in the
00:12:13 --> 00:12:14 radio sky.
00:12:15 --> 00:12:18 Anna: Very much so. The foreground emission from
00:12:18 --> 00:12:21 our own galaxy is around 10 times
00:12:21 --> 00:12:24 stronger than the hydrogen signal. The
00:12:24 --> 00:12:26 Portsmouth team compared it to making out a
00:12:26 --> 00:12:28 whispered conversation from the front row of
00:12:28 --> 00:12:29 a rock concert.
00:12:30 --> 00:12:32 Avery: So how did they do it?
00:12:32 --> 00:12:34 Anna: With a new way of using the telescope,
00:12:35 --> 00:12:37 Meerkat normally combines its 64 dishes
00:12:37 --> 00:12:40 as one interferometer, which gives sharp
00:12:40 --> 00:12:43 images. For this survey, they ran each
00:12:43 --> 00:12:45 dish as its own independent telescope, giving
00:12:45 --> 00:12:48 up resolution for speed and sky coverage.
00:12:49 --> 00:12:51 Then they split the data into independent
00:12:51 --> 00:12:54 subsets by dish and by observing time,
00:12:54 --> 00:12:56 cleaned each one and cross compared them.
00:12:57 --> 00:12:59 Real cosmic structure shows up in all of
00:12:59 --> 00:13:01 them. Instrument quirks don't.
00:13:01 --> 00:13:02 Avery: And the result?
00:13:03 --> 00:13:06 Anna: The paper in Monthly Notices of the Royal
00:13:06 --> 00:13:08 Astronomical Society reports the
00:13:08 --> 00:13:10 hydrogen signal at a redshift of
00:13:10 --> 00:13:13 0.42 light that set
00:13:13 --> 00:13:15 out about four and a half billion years ago
00:13:16 --> 00:13:19 over about 236 square degrees
00:13:19 --> 00:13:21 from the 2021 observing campaign.
00:13:22 --> 00:13:25 The detection comes in at a signal to noise
00:13:25 --> 00:13:27 ratio of 6.2. And
00:13:27 --> 00:13:30 crucially, this is hydrogen measured on its
00:13:30 --> 00:13:33 own without leaning on a separate galaxy
00:13:33 --> 00:13:34 survey to pull the signal out.
00:13:35 --> 00:13:37 Avery: We've covered meerkat hydrogen before.
00:13:38 --> 00:13:40 Anna: We m have back in episode 186.
00:13:41 --> 00:13:43 That was a detection using MeerKAT's
00:13:43 --> 00:13:46 interferometer mode on smaller scales.
00:13:46 --> 00:13:49 This one is single dish mode on the large
00:13:49 --> 00:13:52 cosmological scales that matter for mapping
00:13:52 --> 00:13:54 the cosmic web and and eventually dark
00:13:54 --> 00:13:57 energy. Different method, different
00:13:57 --> 00:13:57 scales.
00:13:58 --> 00:13:59 Avery: Any caveats?
00:13:59 --> 00:14:02 Anna: An honest one in the paper itself.
00:14:02 --> 00:14:05 Each data subset on its own still showed
00:14:05 --> 00:14:07 excess power the team attributes to
00:14:07 --> 00:14:10 unresolved systematics. So the detection
00:14:10 --> 00:14:12 rests on the cross correlations between
00:14:12 --> 00:14:15 subsets and, um, the constraint on how much
00:14:15 --> 00:14:18 hydrogen there is remains broad. This
00:14:18 --> 00:14:20 is proof that the method works. Not a
00:14:20 --> 00:14:22 precision cosmology result yet.
00:14:23 --> 00:14:24 Avery: And where it's heading
00:14:25 --> 00:14:28 Anna: into the SKA meerkat will
00:14:28 --> 00:14:30 be folded into SKA Mid in South Africa,
00:14:31 --> 00:14:34 the sibling of SKA Lo being built in
00:14:34 --> 00:14:36 Western Australia. The survey's
00:14:36 --> 00:14:39 principal Investigator Mario Santos at the
00:14:39 --> 00:14:42 University of the Western Cape called it a
00:14:42 --> 00:14:45 milestone for intensity mapping as a
00:14:45 --> 00:14:46 cosmology tool.
00:14:47 --> 00:14:49 Southern Hemisphere Radio Doing the
00:14:49 --> 00:14:51 groundwork for the next generation
00:14:52 --> 00:14:55 Avery: Europe's Euclid Space Telescope has now
00:14:55 --> 00:14:57 opened its first major public data release to
00:14:57 --> 00:15:00 the world. It's called Dr. One foundation
00:15:00 --> 00:15:03 and it's big about 1900 square
00:15:03 --> 00:15:06 degrees of sky imaging, catalogues and
00:15:06 --> 00:15:08 spectra adding up to roughly 1.8
00:15:08 --> 00:15:09 petabytes of data.
00:15:10 --> 00:15:13 Anna: And for our southern listeners, this one
00:15:13 --> 00:15:14 leans our way.
00:15:14 --> 00:15:16 Avery: It does. Of those 1900
00:15:17 --> 00:15:19 square degrees of the Euclid wide survey,
00:15:19 --> 00:15:22 about 1400 are in the southern sky
00:15:22 --> 00:15:24 and about 500 in the northern. The
00:15:24 --> 00:15:27 observations were taken between February
00:15:27 --> 00:15:29 2024 and May 2025,
00:15:30 --> 00:15:32 plus the Euclid deep fields and raw data from
00:15:32 --> 00:15:33 launch onward.
00:15:34 --> 00:15:35 Anna: What's not in it yet?
00:15:35 --> 00:15:38 Avery: The headline Cosmology Euclid's core
00:15:38 --> 00:15:41 job is measuring dark matter and dark energy
00:15:41 --> 00:15:44 through weak gravitational lensing and galaxy
00:15:44 --> 00:15:46 clustering. And those higher level science
00:15:46 --> 00:15:49 products come in the complete Dr.1 expected
00:15:49 --> 00:15:51 in mid-2027. ESA moved them
00:15:51 --> 00:15:54 back to make sure they're properly validated,
00:15:54 --> 00:15:57 so nobody should expect a uh, dark energy
00:15:57 --> 00:15:58 verdict this week.
00:15:58 --> 00:16:01 Anna: So what is the foundation release good for
00:16:02 --> 00:16:05 Avery: discovery at this scale, the rarest
00:16:05 --> 00:16:07 objects start turning strong gravitational
00:16:07 --> 00:16:10 lenses, odd uh, galaxy shapes edge on
00:16:10 --> 00:16:13 planet forming discs, collisional ring
00:16:13 --> 00:16:16 galaxies. ESA is even running a hackathon
00:16:16 --> 00:16:19 from the 23rd to the 26th of November where
00:16:19 --> 00:16:21 teams compete to find the strangest things in
00:16:21 --> 00:16:23 the R1, with the finds going into a peer
00:16:23 --> 00:16:24 reviewed catalogue.
00:16:25 --> 00:16:27 Anna: And it ties in with a story we've been
00:16:27 --> 00:16:27 following.
00:16:28 --> 00:16:31 Avery: The footprint overlaps the areas NASA's Roman
00:16:31 --> 00:16:33 Space Telescope will survey at high galactic
00:16:33 --> 00:16:36 latitude Euclid wide and shallow
00:16:36 --> 00:16:39 ish Roman deeper and sharper on the same
00:16:39 --> 00:16:42 patches and both after the same dark energy
00:16:42 --> 00:16:44 question we've been tracking since September.
00:16:44 --> 00:16:47 Anna: Quick Hits First NASA's Twin
00:16:47 --> 00:16:49 Escapade Spacecraft are on their way to Mars.
00:16:50 --> 00:16:52 LIU fired its engine on the 7th of November
00:16:52 --> 00:16:55 and gold followed on the 9th, each a
00:16:55 --> 00:16:58 roughly 9 minute burn deep in Earth's gravity
00:16:58 --> 00:17:00 well during a close flyby. That's a
00:17:00 --> 00:17:03 powered Earth Gravity Assist, a uh first for
00:17:03 --> 00:17:05 a Mars mission. And both worked.
00:17:05 --> 00:17:08 Arrival is September 2027 with science
00:17:08 --> 00:17:11 in 2028 and this Friday is one
00:17:11 --> 00:17:13 year to the day since they launched.
00:17:14 --> 00:17:17 Avery: Next SpaceX is targeting Friday 13th
00:17:17 --> 00:17:20 November for Starship flight 15 and
00:17:20 --> 00:17:23 uh at 2245 UTC. That's
00:17:23 --> 00:17:25 quarter to five Friday afternoon in Texas and
00:17:25 --> 00:17:28 quarter to ten Saturday morning in Sydney.
00:17:28 --> 00:17:31 It's planned as a 22 hour flight of about 14
00:17:31 --> 00:17:34 orbits, deploying 26 Starlink
00:17:34 --> 00:17:37 satellites. And for the first time, SpaceX
00:17:37 --> 00:17:39 intends to try catching both the booster and
00:17:39 --> 00:17:42 the ship back at the tower. That date is
00:17:42 --> 00:17:45 pending regulatory approval, so treat it as
00:17:45 --> 00:17:45 targeted.
00:17:46 --> 00:17:48 Anna: And finally, a southern story from the
00:17:48 --> 00:17:51 stratosphere. NASA and NOAA say this
00:17:51 --> 00:17:53 year's Antarctic ozone hole was the seventh
00:17:53 --> 00:17:55 largest in 48 years of monitoring,
00:17:56 --> 00:17:58 peaking on 18 September at about
00:17:58 --> 00:18:01 27 million square kilometres. The
00:18:01 --> 00:18:03 cause was an unusually strong persistent
00:18:03 --> 00:18:06 polar vortex and the hole wasn't as deep as
00:18:06 --> 00:18:08 the worst years. They estimate it would have
00:18:08 --> 00:18:10 been noticeably larger without the Montreal
00:18:10 --> 00:18:13 Protocol. And long term Recovery toward the
00:18:13 --> 00:18:15 2000-70s remains on track.
00:18:15 --> 00:18:18 Avery: Time to look up in both hemispheres.
00:18:19 --> 00:18:21 All of tonight's numbers are our own
00:18:21 --> 00:18:23 calculations for Sydney, Los Angeles, New
00:18:23 --> 00:18:24 York and London.
00:18:25 --> 00:18:28 Anna: The big one is the pre dawn meeting of Mars
00:18:28 --> 00:18:30 and Jupiter. They're closing in all week
00:18:31 --> 00:18:33 and reach their minimum separation on the
00:18:33 --> 00:18:36 16th of November. About 1.2
00:18:36 --> 00:18:38 degrees apart, a little more than two full
00:18:38 --> 00:18:41 moon widths. I'm listing quote, less than
00:18:41 --> 00:18:44 a degree. Our own figure is 1.19
00:18:45 --> 00:18:47 Avery: and this one belongs to the north.
00:18:48 --> 00:18:50 45 minutes before sunrise, the pair
00:18:50 --> 00:18:53 stands around 65 to 70 degrees up
00:18:53 --> 00:18:56 from Los Angeles and New York and over 50
00:18:56 --> 00:18:59 from London. From Sydney it's about 30
00:18:59 --> 00:19:02 degrees up, still easy but lower. Look for
00:19:02 --> 00:19:04 Jupiter as the bright one and Mars as the
00:19:04 --> 00:19:06 fainter orange one beside it.
00:19:06 --> 00:19:09 Anna: Low in the east before dawn,
00:19:09 --> 00:19:12 Venus is sitting just over a degree from
00:19:12 --> 00:19:14 Spica, the brightest star in Virgo.
00:19:15 --> 00:19:18 Venus is a thin crescent right now only
00:19:18 --> 00:19:21 about 10% lit, but 54
00:19:21 --> 00:19:23 arcseconds across, so even steadily held
00:19:23 --> 00:19:26 binoculars will show the shape. It turns
00:19:26 --> 00:19:29 stationary on the 11th and starts moving
00:19:29 --> 00:19:31 eastward against the stars again.
00:19:31 --> 00:19:34 Avery: Again a northern advantage. Venus is
00:19:34 --> 00:19:37 about 12 to 15 degrees up 45
00:19:37 --> 00:19:39 minutes before sunrise from the northern
00:19:39 --> 00:19:42 cities and only about 7 from Sydney.
00:19:42 --> 00:19:44 You don't want a flat eastern horizon.
00:19:45 --> 00:19:48 Anna: And a safety note because Venus is close
00:19:48 --> 00:19:51 to the sun, never sweep binoculars or a
00:19:51 --> 00:19:53 telescope toward the sun. And if you ever
00:19:53 --> 00:19:56 look at the sun itself, use only filters or
00:19:56 --> 00:19:59 solar viewers Certified to the ISO
00:19:59 --> 00:20:01 123122 standard.
00:20:02 --> 00:20:04 Put the optics away before sunrise.
00:20:04 --> 00:20:07 Avery: The evening belongs to the south two
00:20:07 --> 00:20:10 hours after sunset, Saturn is about 54
00:20:10 --> 00:20:13 degrees up from Sydney against about 45 from
00:20:13 --> 00:20:16 Los Angeles, 39 from New York and 28
00:20:16 --> 00:20:18 from London. The young crescent moon is low
00:20:18 --> 00:20:21 in the west after sunset this week, passing
00:20:21 --> 00:20:23 through Scorpius and Sagittarius. Australia
00:20:24 --> 00:20:26 was even treated to a daytime occultation of
00:20:26 --> 00:20:29 antares by the Moon on Wednesday afternoon.
00:20:29 --> 00:20:32 First quarter is on the 17th of November and
00:20:32 --> 00:20:33 full moon on the 24th.
00:20:34 --> 00:20:36 Anna: The Leonid meteor shower peaks on the night
00:20:36 --> 00:20:39 of the 17th into the 18th. The
00:20:39 --> 00:20:42 first quarter moon sets around midnight, so
00:20:42 --> 00:20:44 the hours before dawn are dark.
00:20:44 --> 00:20:47 Avery: And here we have to be honest, the
00:20:47 --> 00:20:50 Leonids favour the north at 4 in
00:20:50 --> 00:20:52 the morning. The radiant in Leo is about
00:20:52 --> 00:20:55 55 to 58 degrees up from Los
00:20:55 --> 00:20:57 Angeles and New York and around 49 from
00:20:57 --> 00:21:00 London, but only about 16 degrees from
00:21:00 --> 00:21:03 Sydney. Southern observers will see fewer,
00:21:03 --> 00:21:05 but the ones that do come in at a low angle
00:21:05 --> 00:21:08 can be long, graceful Earth grazers.
00:21:08 --> 00:21:11 Anna: So this week, the north gets Mars and
00:21:11 --> 00:21:14 Jupiter, Venus and the Leonids.
00:21:14 --> 00:21:17 The south gets Saturn high overhead
00:21:17 --> 00:21:19 and the better evening moon.
00:21:20 --> 00:21:23 Avery: Some weeks it runs the other way. Clear skies
00:21:23 --> 00:21:24 wherever you are.
00:21:24 --> 00:21:27 Anna: That's Astronomy dately for today. A
00:21:27 --> 00:21:29 planet that stopped crossing its star and
00:21:29 --> 00:21:32 should be back within half a century. Ice
00:21:32 --> 00:21:35 giants whose magnetic fields may have moved
00:21:35 --> 00:21:37 since Voyager. Hydrogen clustering
00:21:37 --> 00:21:40 heard from the Karoo and Euclid
00:21:40 --> 00:21:41 opening its doors.
00:21:42 --> 00:21:45 Avery: Coming up, Starship Flight 15's double
00:21:45 --> 00:21:47 catch attempt. Voyager 1 reaching one
00:21:47 --> 00:21:50 light day from Earth around the 18th and
00:21:50 --> 00:21:53 BepiColombo arriving in orbit at Mercury on
00:21:53 --> 00:21:54 the 21st.
00:21:54 --> 00:21:56 Anna: You can find show notes, links and every
00:21:56 --> 00:21:59 episode@astronomydaily.IO and if
00:21:59 --> 00:22:01 you've got a question you'd like us to chase,
00:22:01 --> 00:22:04 the contact form is there too. I'm Anna.
00:22:05 --> 00:22:08 Avery: And I'm, um. Avery. Keep looking up,
00:22:20 --> 00:22:31