Betelgeuse is being haunted. New VLA and ALMA radio observations show the red supergiant's atmosphere stretches and relaxes in step with the orbit of its hidden companion, Siwarha — a companion too faint to see in radio, caught by the ripples it leaves behind. Also: lithium-fluoride crystals that rode around the Moon on Artemis I, why comets almost certainly didn't deliver life's ingredients to Earth (but did better on Mars), and Virgin Galactic's new spaceship, Apeiron. Plus Swift's final days, Hubble helping Roman, Starship Flight 15, and where to find Betelgeuse tonight from both hemispheres.Show notes
The Ghost in Betelgeuse · Matthews (MIT Haystack), Dupree (CfA), Richards (Manchester) and Dent (ESO/ALMA) imaged Betelgeuse at seven frequencies, 22–485 GHz, with the VLA and ALMA between 2021 and 2026. · The outer atmosphere has recovered from the 2019–20 Great Dimming (~3,500 K at 22 GHz); a temperature minimum of ~2,220 K sits at ~1.2 stellar radii, matching the infrared 'MOLsphere'. · The star's ellipticity tracks the orbital phase of its companion Siwarha: more stretched near greatest elongation (~10% in Oct 2024), rounder near transit and eclipse (<2% in Apr 2026). · Caveats: small effect, ~9 epochs, frequency-dependent orientation puzzle, Siwarha's nature contested; preprint posted August 2026. · Next: Siwarha re-emerges on the far side of Betelgeuse in late 2027. Crystals That Went Around the Moon · Bilski et al. (IFJ PAN, DLR), Radiation Measurements: LiF fluorescent nuclear track detectors from the MARE phantoms on Artemis I reconstructed the cosmic-ray energy-deposition spectrum without destroying the detector. · Matched plastic track detectors at intermediate energies; ~30% overestimate for the heaviest ions, attributed to neutron knock-on of lithium nuclei; lithium-7 crystals reduce it. · Near the Moon, dose was higher than in low Earth orbit but less than intuition suggests, and more evenly spread through the body. Comets Probably Didn't Seed Life on Earth · Anslow et al. (Cambridge), Scientific Reports: rapid decline of the bombardment, comet break-up, atmospheric filtering, impact heating and crater-lake dilution make HCN delivery to early Earth 'exceedingly rare'. · Delivery to Mars is about five times more effective (lower impact speeds, thinner atmosphere). · Caveat: modelling, focused on HCN; doesn't exclude delivery in tightly packed exoplanet systems. Virgin Galactic's Apeiron Comes Home · First Delta-class spaceplane named Apeiron ('boundless') on 28 Oct and flown under mothership Eve from Mesa, Arizona to Spaceport America. · Flight tests next; customer flights targeted mid-2027; second ship late 2027; target twice-weekly flights and 500+ missions per vehicle. Quick Hits · Swift ended operations 20 Oct; NASA expects re-entry within weeks. · Hubble lens image DESI J194.5345+03.5358 released to help calibrate Roman's ~160,000 expected strong lenses (image release, no new paper). · Starship Flight 15 targeted for November with a two-stage catch attempt; no official date. Skywatch · Betelgeuse rises ~22:33 Sydney, 21:48 LA, 21:46 NY, 20:39 London (Fri 30 Oct); highest before dawn: 49° Sydney, 63° LA, 57° NY, 46° London. US clocks fall back Sun 1 Nov. · Saturn at dusk; Mercury's last evening appearance favours the south (~11° at sunset from Sydney). · Pre-dawn Mars–Jupiter closing: 6.5° (this weekend), ~4° (5 Nov), ~1.2° (16 Nov). Last quarter Moon 1 Nov 20:28 UTC; Moon past Mars, Jupiter and Regulus 2–3 Nov. · Zodiacal light: evening west from the south, pre-dawn east from the north. Solar viewing only with ISO 12312-2 filters. Sources · NRAO via Newswise — What Lurks Within the Shadows of Betelgeuse? — https://www.newswise.com/articles/what-lurks-within-the-shadows-of-betelgeuse · Matthews et al., arXiv 2608.02847 — https://arxiv.org/abs/2608.02847 · Bilski et al., Radiation Measurements (DLR elib record) — https://elib.dlr.de/226596/ · Universe Today — Glowing Salt Crystals Tracked Radiation Aboard Artemis I — https://www.universetoday.com/articles/glowing-salt-crystals-tracked-radiation-aboard-artemis-i · Anslow et al., Scientific Reports — https://www.nature.com/articles/s41598-026-74214-y · Universe Today — Ancient Comets Carried Organic Compounds… — https://www.universetoday.com/articles/ancient-comets-carried-organic-compounds-but-they-didnt-survive-crashing-into-earth · Universe Today — Virgin Galactic Flies Next-Gen Space Plane… — https://www.universetoday.com/articles/virgin-galactic-flies-next-gen-space-plane-to-new-home-with-new-name · 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/ · NASA — Hubble Charts Path for Roman with Gravitational Lenses — https://science.nasa.gov/?p=1462412
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This episode includes AI-generated content.
00:00:00 --> 00:00:02 Anna: Hello, everyone. Thanks for taking the time
00:00:02 --> 00:00:04 to listen. Today's headline.
00:00:04 --> 00:00:07 There's a star in Orion that's being
00:00:07 --> 00:00:10 haunted. Something is moving through its
00:00:10 --> 00:00:13 outer atmosphere, stirring it up, pulling it
00:00:13 --> 00:00:13 out of shape.
00:00:14 --> 00:00:16 And nobody can see the thing doing it. Not in
00:00:16 --> 00:00:17 radio, anyway.
00:00:17 --> 00:00:19 Avery: Just in time for Halloween. Today,
00:00:20 --> 00:00:22 Betelgeuse and the ghost inside it.
00:00:23 --> 00:00:25 How two of the world's great radio telescopes
00:00:25 --> 00:00:28 caught a hidden companion by the ripples it
00:00:28 --> 00:00:28 leaves behind.
00:00:29 --> 00:00:32 Anna: Welcome to Astronomy AstroDailyPod. I'm Anna.
00:00:32 --> 00:00:35 Avery: And I'm Avery. Also today, crystals
00:00:35 --> 00:00:38 that rode around the moon on Artemis 1 and
00:00:38 --> 00:00:40 came home carrying the tracks of cosmic rays.
00:00:41 --> 00:00:43 A new study that says comets almost certainly
00:00:43 --> 00:00:46 didn't seed life on Earth, but might have
00:00:46 --> 00:00:47 done better on Mars.
00:00:47 --> 00:00:50 And Virgin Galactic's new spaceship gets a
00:00:50 --> 00:00:51 name and a home.
00:00:51 --> 00:00:54 Anna: Plus, Swift's final days. Hubble
00:00:54 --> 00:00:56 getting Roman ready, and where to find
00:00:56 --> 00:00:58 Betelgeuse tonight. Let's go.
00:00:59 --> 00:01:01 Avery: It's Halloween, so I'm guessing you have
00:01:01 --> 00:01:02 something on theme to get us going.
00:01:03 --> 00:01:05 Anna: Let's start with the star itself. Because
00:01:05 --> 00:01:08 Betelgeuse is not a normal star.
00:01:08 --> 00:01:11 It's a red supergiant, the bright orange
00:01:11 --> 00:01:14 red shoulder of Orion. And it is
00:01:14 --> 00:01:17 enormous. Put it where the sun is and its
00:01:17 --> 00:01:19 surface would reach somewhere out past the
00:01:19 --> 00:01:20 orbit of Mars.
00:01:20 --> 00:01:23 Avery: Um, and it's close enough and big enough that
00:01:23 --> 00:01:25 it's one of the very few stars we can
00:01:25 --> 00:01:28 actually resolve as a disc rather than a
00:01:28 --> 00:01:30 point. It was the first star other than the
00:01:30 --> 00:01:33 sun ever directly imaged by hubble back in
00:01:33 --> 00:01:34 1996.
00:01:34 --> 00:01:37 Anna: It's also famously restless. In
00:01:37 --> 00:01:40 late 2019 and early 2020, it went
00:01:40 --> 00:01:43 through what's now called the great dimming.
00:01:43 --> 00:01:45 By February 2020, it had faded to its
00:01:45 --> 00:01:48 faintest in more than a century of records.
00:01:48 --> 00:01:50 People genuinely wondered whether it was
00:01:50 --> 00:01:52 about to go supernova.
00:01:52 --> 00:01:55 Avery: It didn't. The dimming turned out to be
00:01:55 --> 00:01:58 a huge surface mass ejection, a
00:01:58 --> 00:02:00 shock wave from deep convection that threw
00:02:00 --> 00:02:03 out gas, which cooled and formed dust
00:02:03 --> 00:02:04 and blocked our view for a few months.
00:02:05 --> 00:02:08 Anna: But Betelgeuse has a second slower rhythm
00:02:08 --> 00:02:10 that has puzzled astronomers for a long time.
00:02:11 --> 00:02:13 On m top of its roughly 400 day pulsation,
00:02:14 --> 00:02:17 it brightens and fades over about 2
00:02:17 --> 00:02:17 days.
00:02:18 --> 00:02:19 Call it 5.8 years.
00:02:20 --> 00:02:22 Avery: And that's where the Ghost comes in. In
00:02:22 --> 00:02:25 2024, two independent teams went back
00:02:25 --> 00:02:28 through more than a century of brightness,
00:02:28 --> 00:02:30 velocity and position measurements and came
00:02:30 --> 00:02:33 to the same. That long period
00:02:33 --> 00:02:35 is a companion star in orbit?
00:02:36 --> 00:02:37 Anna: Not just in orbit.
00:02:37 --> 00:02:40 In orbit inside Betelgeuse's extended
00:02:40 --> 00:02:43 atmosphere. The companion circles at
00:02:43 --> 00:02:46 about 2.3 times the radius of the visible
00:02:46 --> 00:02:48 star, which for a star this size means.
00:02:49 --> 00:02:50 Means it's ploughing through the giant's
00:02:50 --> 00:02:51 outer layers of gas.
00:02:52 --> 00:02:54 Avery: It now has a name. Siwarha
00:02:55 --> 00:02:58 Betelgurst comes from an Arabic phrase
00:02:58 --> 00:03:00 usually read as the hand of Al Jawza.
00:03:00 --> 00:03:03 So the companion was named for her bracelet.
00:03:03 --> 00:03:05 The International Astronomical Union adopted
00:03:05 --> 00:03:06 it this year
00:03:06 --> 00:03:09 Anna: and the evidence has been building fast.
00:03:09 --> 00:03:12 Speckle imaging gave a tentative detection in
00:03:12 --> 00:03:15 2025. In January this year, a team
00:03:15 --> 00:03:17 led by Andrea Dupree at the Centre for
00:03:17 --> 00:03:19 Astrophysics used Hubble and ground based
00:03:19 --> 00:03:22 spectra to what looks like a wake, a
00:03:22 --> 00:03:25 dense trail of gas left behind the companion
00:03:25 --> 00:03:25 as it moves.
00:03:26 --> 00:03:28 And then, using the Sphere instrument on
00:03:28 --> 00:03:31 ESO's Very Large Telescope at Paranal in
00:03:31 --> 00:03:34 Chile, a team led by Miguel Montargis
00:03:34 --> 00:03:36 reported a direct detection of the companion
00:03:36 --> 00:03:38 itself at about six sigma.
00:03:39 --> 00:03:41 Avery: So by now we're fairly confident it's there.
00:03:42 --> 00:03:44 The new question is, what is it doing to
00:03:44 --> 00:03:45 Betelgeuse?
00:03:45 --> 00:03:48 Anna: This is the new paper led by Lynn Matthews of
00:03:48 --> 00:03:51 MIT's Haystack Observatory with Andrea
00:03:51 --> 00:03:54 Dupre, Anita Richards at the University of
00:03:54 --> 00:03:57 Manchester and Bill Dent at ESO and
00:03:57 --> 00:03:59 alma. It's published in the Astronomical
00:03:59 --> 00:04:02 Journal and the National Radio Astronomy
00:04:02 --> 00:04:03 Observatory released it this week.
00:04:03 --> 00:04:06 Avery: They observed Betelgeuse at seven radio
00:04:06 --> 00:04:09 frequencies from 22 GHz
00:04:09 --> 00:04:11 up to 485 GHz
00:04:12 --> 00:04:15 between 2021 and 2026.
00:04:15 --> 00:04:18 The two lowest came from the Very Large Array
00:04:18 --> 00:04:21 in New Mexico. The other five came from
00:04:21 --> 00:04:23 alma, high on the Chagnator Plateau in
00:04:23 --> 00:04:24 Chile.
00:04:24 --> 00:04:27 Anna: And here's why seven frequencies matter
00:04:27 --> 00:04:30 in radio. A, uh, star's atmosphere is
00:04:30 --> 00:04:30 opaque.
00:04:31 --> 00:04:33 But how opaque depends on the wavelength.
00:04:33 --> 00:04:36 Longer wavelengths only let you see the
00:04:36 --> 00:04:38 higher outer layers. Shorter
00:04:38 --> 00:04:41 wavelengths let you see deeper in. So
00:04:41 --> 00:04:43 stacking seven frequencies is like slicing
00:04:43 --> 00:04:46 the atmosphere into layers from just above
00:04:46 --> 00:04:49 the visible surface out to nearly three times
00:04:49 --> 00:04:50 the star's radius.
00:04:50 --> 00:04:53 Avery: A CT scan of a star more or less with
00:04:53 --> 00:04:56 a disc only about a, uh, 20th of an arc
00:04:56 --> 00:04:57 second across
00:04:57 --> 00:05:00 Anna: three things. First, Betelgeuse has
00:05:00 --> 00:05:03 recovered from the great dimming. Back in
00:05:03 --> 00:05:05 2019, just before the dimming, Matthews and
00:05:05 --> 00:05:07 Dupree had found the outer atmosphere
00:05:07 --> 00:05:10 unusually cold in radio, a sign of that
00:05:10 --> 00:05:13 shock passing through. Now, at 22
00:05:13 --> 00:05:15 gigahertz, the gas is back to about
00:05:15 --> 00:05:18 3 kelvin, roughly the
00:05:18 --> 00:05:19 temperature of the star's own surface.
00:05:20 --> 00:05:22 Avery: Second, they've pinned down a temperature
00:05:22 --> 00:05:22 minimum.
00:05:23 --> 00:05:26 Go deeper with Alma's highest frequency to
00:05:26 --> 00:05:29 about 1.2 times the star's radius and the
00:05:29 --> 00:05:31 gas drops to about 2
00:05:31 --> 00:05:33 kelvin. That's more than 1 degrees
00:05:33 --> 00:05:35 cooler than the visible surface underneath
00:05:35 --> 00:05:36 it.
00:05:36 --> 00:05:39 Anna: Which sounds backwards hotter surface,
00:05:39 --> 00:05:41 cooler layer, then hotter again further out
00:05:41 --> 00:05:44 where the chromosphere is. But it matches a
00:05:44 --> 00:05:47 shell of molecular gas, the so called MOL
00:05:47 --> 00:05:50 spherethat infrared astronomers have inferred
00:05:50 --> 00:05:52 for years. The radio measurement says that
00:05:52 --> 00:05:54 cool gas really does dominate that region.
00:05:55 --> 00:05:58 Avery: And third, the ghost. The team
00:05:58 --> 00:06:00 fitted the shape of Betelgeuse at every
00:06:00 --> 00:06:03 frequency and every date, and the star isn't
00:06:03 --> 00:06:06 quite round, it's slightly egg shaped. What
00:06:06 --> 00:06:08 they notice is that how egg shaped it is
00:06:08 --> 00:06:10 seems to track where the companion is in its
00:06:10 --> 00:06:11 orbit.
00:06:11 --> 00:06:14 Anna: When Swarha is at its greatest apparent
00:06:14 --> 00:06:16 distance from the star off to one side,
00:06:16 --> 00:06:19 Betelgeuse looks more stretched. When
00:06:19 --> 00:06:21 Swarha is passing in front of the star or
00:06:21 --> 00:06:24 hidden behind it, Betelgeuse looks rounder.
00:06:24 --> 00:06:27 The clearest Single example in October
00:06:27 --> 00:06:30 2024, near greatest separation, the
00:06:30 --> 00:06:32 star was about 10% out of round. In
00:06:32 --> 00:06:34 April this year, near the companion's
00:06:34 --> 00:06:36 eclipse, it was under 2%
00:06:37 --> 00:06:40 Avery: and the companion itself completely
00:06:40 --> 00:06:42 invisible. At these wavelengths, the team
00:06:42 --> 00:06:45 worked out, it would be tens to hundreds of
00:06:45 --> 00:06:48 times too faint to detect. Matthew's
00:06:48 --> 00:06:50 summary is that it actually passes through
00:06:50 --> 00:06:51 its extended atmosphere.
00:06:51 --> 00:06:53 And what they see is the disturbance,
00:06:54 --> 00:06:57 Anna: like watching ripples on a pond and
00:06:57 --> 00:06:59 inferring something moving just under the
00:06:59 --> 00:07:00 surface.
00:07:00 --> 00:07:03 Avery: And this needs the honest version. The effect
00:07:03 --> 00:07:05 is small. The star is never more than about
00:07:05 --> 00:07:07 10% out of round.
00:07:07 --> 00:07:10 The correlation rests on around nine epochs,
00:07:10 --> 00:07:12 and a few of those come from earlier papers
00:07:12 --> 00:07:15 by other teams. That's a pattern worth taking
00:07:15 --> 00:07:17 seriously, not a closed case.
00:07:17 --> 00:07:20 Anna: There's also a genuine puzzle. The authors
00:07:20 --> 00:07:23 flag themselves. The direction of the
00:07:23 --> 00:07:26 stretch isn't the same at every frequency.
00:07:26 --> 00:07:29 The highest ALMA bands, the middle ALMA
00:07:29 --> 00:07:31 bands and the VLA bands are all point
00:07:31 --> 00:07:34 different ways. One possibility is that
00:07:34 --> 00:07:36 different depths are cutting through
00:07:36 --> 00:07:38 different parts of a three dimensional wake.
00:07:39 --> 00:07:42 But that's an idea to test, not a result.
00:07:42 --> 00:07:44 Avery: And what suwarhat actually is
00:07:45 --> 00:07:47 remains contested. Estimates of its
00:07:47 --> 00:07:50 mass run from around half a solar mass to
00:07:50 --> 00:07:51 roughly 3.
00:07:52 --> 00:07:54 Even the distance to Betelgeuse is uncertain.
00:07:55 --> 00:07:57 This paper uses about 720 light
00:07:57 --> 00:08:00 years, while the figure you'll usually see is
00:08:00 --> 00:08:02 around 651.
00:08:02 --> 00:08:05 Anna: More disclosure A preprint of this work
00:08:05 --> 00:08:08 appeared in early August, so the journal
00:08:08 --> 00:08:11 publication is what's new this week, not the
00:08:11 --> 00:08:11 first sight of the data?
00:08:12 --> 00:08:15 Avery: Why care? Because the companion is orbiting
00:08:15 --> 00:08:17 right in the zone where Betelgeuse launches
00:08:17 --> 00:08:17 its wind.
00:08:18 --> 00:08:21 The region where a red supergiant sheds the
00:08:21 --> 00:08:23 mass it loses on the way to its eventual
00:08:23 --> 00:08:26 supernova. If a companion is shaping that
00:08:26 --> 00:08:28 region, it changes how we model the star's
00:08:28 --> 00:08:31 last stages. And not just for Betelgeuse.
00:08:31 --> 00:08:34 Anna: And there's a southern thread worth naming.
00:08:34 --> 00:08:37 Five of the seven frequencies came from Alma
00:08:37 --> 00:08:39 in the Atacama, including the deepest layer.
00:08:40 --> 00:08:42 One of the authors is at eso. And the direct
00:08:42 --> 00:08:45 detection came from Paranol. The northern
00:08:45 --> 00:08:48 Vla and the southern dishes together built
00:08:48 --> 00:08:48 the picture.
00:08:49 --> 00:08:51 Avery: The next beat has a date on it. Roughly.
00:08:51 --> 00:08:54 Cewarja is currently on the far side of
00:08:54 --> 00:08:56 Bedel. Geese from us. It should swing back
00:08:56 --> 00:08:59 into view on the opposite side in late
00:08:59 --> 00:09:02 2027. Teams are already planning to be
00:09:02 --> 00:09:05 watching in radio, in the ultraviolet and
00:09:05 --> 00:09:06 with adaptive optics.
00:09:06 --> 00:09:09 Anna: So the ghost comes back out in a year.
00:09:10 --> 00:09:11 Rather fitting.
00:09:11 --> 00:09:14 Avery: When Artemis 1 flew around the moon in late
00:09:14 --> 00:09:16 2022, there were no astronauts on board.
00:09:17 --> 00:09:20 But there were two passengers. Mannequins
00:09:20 --> 00:09:23 called Helga and Zohar, built to mimic
00:09:23 --> 00:09:25 human bone and soft tissue and packed with
00:09:25 --> 00:09:27 thousands of radiation detectors. That was
00:09:27 --> 00:09:29 the MER experiment, led by the German
00:09:29 --> 00:09:30 Aerospace Centre.
00:09:31 --> 00:09:33 Anna: And some of the most interesting detectors on
00:09:33 --> 00:09:36 board were tiny crystals of lithium
00:09:36 --> 00:09:39 fluoride, made by the Institute of Nuclear
00:09:39 --> 00:09:41 Physics of the Polish Academy of Sciences in
00:09:41 --> 00:09:42 Krakow.
00:09:42 --> 00:09:45 Avery: A new paper led by Pawel Bilski in the
00:09:45 --> 00:09:47 journal Radiation Measurements, reports how
00:09:47 --> 00:09:50 those crystals did m. The idea is clever.
00:09:51 --> 00:09:53 When a cosmic ray particle tears through the
00:09:53 --> 00:09:56 crystal, it knocks electrons loose and leaves
00:09:56 --> 00:09:59 a permanent defect along its path. Later,
00:09:59 --> 00:10:01 in the lab, you shine a laser through the
00:10:01 --> 00:10:03 crystal under a microscope and the particle's
00:10:03 --> 00:10:04 track glows blue.
00:10:05 --> 00:10:08 Anna: And the advantage over the old method is big.
00:10:08 --> 00:10:10 The standard track detectors are plastic. To
00:10:10 --> 00:10:12 read them, you soak them for hours in hot
00:10:12 --> 00:10:15 caustic soda to etch the tracks out, which
00:10:15 --> 00:10:17 destroys the detector and makes hazardous
00:10:17 --> 00:10:19 waste. The crystal can be read without
00:10:19 --> 00:10:20 destroying it.
00:10:21 --> 00:10:23 Avery: The team stacked microscope images taken a
00:10:23 --> 00:10:26 micrometre apart and followed each track
00:10:26 --> 00:10:28 through the crystal in three dimensions. That
00:10:28 --> 00:10:30 let them rebuild the full spectrum of how
00:10:30 --> 00:10:32 much energy each particle dumped along its
00:10:32 --> 00:10:34 path, which is what matters biologically.
00:10:35 --> 00:10:37 Heavy ions dump a lot of energy in a short
00:10:37 --> 00:10:39 distance, and that's the dangerous part of
00:10:39 --> 00:10:40 deep space radiation.
00:10:41 --> 00:10:43 Anna: For middling energies, the crystals matched
00:10:43 --> 00:10:45 the plastic detectors flying right beside
00:10:45 --> 00:10:47 them. For the heaviest hitters, they
00:10:47 --> 00:10:50 overestimated the dose by about 30%.
00:10:51 --> 00:10:53 The team's explanation is that fast neutrons
00:10:53 --> 00:10:55 can knock a lithium nucleus out of place
00:10:55 --> 00:10:58 inside the crystal, which leaves a track of
00:10:58 --> 00:11:00 its own. Crystals made with lithium 7
00:11:00 --> 00:11:01 reduce that
00:11:02 --> 00:11:04 Avery: the broader MARI results are worth hearing
00:11:04 --> 00:11:07 too. Near the Moon, the dose was higher than
00:11:07 --> 00:11:09 in low Earth orbit, but not by as much as you
00:11:09 --> 00:11:12 might expect in Earth orbit. A big chunk of
00:11:12 --> 00:11:14 an astronaut's dose comes from protons
00:11:14 --> 00:11:17 trapped in the Van Allen Belt out by the
00:11:17 --> 00:11:19 Moon. Those are gone and what's left is
00:11:19 --> 00:11:22 galactic cosmic radiation, which is so
00:11:22 --> 00:11:24 energetic it passes straight through the
00:11:24 --> 00:11:24 body.
00:11:25 --> 00:11:27 Anna: Which also means the dose was spread more
00:11:27 --> 00:11:29 evenly through the mannequins.
00:11:29 --> 00:11:32 Less a surface sunburn, more something that
00:11:32 --> 00:11:33 goes all the way through.
00:11:35 --> 00:11:37 Avery: This is a methods paper with
00:11:37 --> 00:11:40 preliminary numbers, not a full risk
00:11:40 --> 00:11:43 assessment for crews and Artemis. I flew
00:11:43 --> 00:11:45 near solar maximum when the sun shields us
00:11:45 --> 00:11:48 best from galactic cosmic rays. As we
00:11:48 --> 00:11:51 said back in episode 193, that shield
00:11:51 --> 00:11:53 weakens as the cycle quietens.
00:11:53 --> 00:11:56 Anna: Which matters for the crews who'll go back to
00:11:56 --> 00:11:58 deep space after next year's Artemis 3 test
00:11:58 --> 00:12:01 in Earth orbit, they'll be flying as the sun
00:12:01 --> 00:12:02 winds down.
00:12:03 --> 00:12:05 Avery: Next up, a bit of myth busting.
00:12:05 --> 00:12:08 Anna: It's one of the most romantic ideas in
00:12:08 --> 00:12:11 planetary science that comets delivered
00:12:11 --> 00:12:13 the ingredients for life to the young Earth.
00:12:13 --> 00:12:16 And it's not baseless. Rosetta found
00:12:16 --> 00:12:19 glycine, an, um, amino acid and
00:12:19 --> 00:12:21 phosphorus at, uh, Comet 67P.
00:12:22 --> 00:12:25 Comets are rich in hydrogen cyanide, which
00:12:25 --> 00:12:27 chemists rate as one of the key starting
00:12:27 --> 00:12:29 molecules for building life's components.
00:12:30 --> 00:12:32 Avery: A new study says the delivery almost
00:12:32 --> 00:12:35 certainly didn't work. It's led by Richard
00:12:35 --> 00:12:37 Anslow at the University of Cambridge's
00:12:37 --> 00:12:39 Institute of Astronomy, published in
00:12:39 --> 00:12:42 Scientific Reports. And in Anslow's own
00:12:42 --> 00:12:45 words, it's kind of a romantic idea. But
00:12:45 --> 00:12:47 their results suggest it's highly unlikely.
00:12:47 --> 00:12:50 Anna: The team modelled Earth's whole early
00:12:50 --> 00:12:53 comet bombardment, focusing on the
00:12:53 --> 00:12:55 slower short period comets, because those
00:12:55 --> 00:12:57 give the molecules their best chance.
00:12:58 --> 00:13:00 And then they ran into one problem
00:13:01 --> 00:13:01 after another.
00:13:02 --> 00:13:05 Avery: First, the bombardment fell away fast, within
00:13:05 --> 00:13:08 roughly the first 500 million years.
00:13:08 --> 00:13:11 Second, many small comets tear themselves
00:13:11 --> 00:13:14 apart on the way in. Outgassing spins them
00:13:14 --> 00:13:17 up until they break. Third, Earth's
00:13:17 --> 00:13:19 atmosphere acts as a filter, destroying small
00:13:19 --> 00:13:21 comets and those coming in at shallow angles.
00:13:22 --> 00:13:25 And fourth, an impact is extremely hot,
00:13:25 --> 00:13:27 and earlier work showed only the gentlest
00:13:27 --> 00:13:29 strikes keep hydrogen cyanide intact.
00:13:30 --> 00:13:33 Anna: And even if some survived, there's a final
00:13:33 --> 00:13:36 twist. A big impact makes a crater
00:13:36 --> 00:13:38 lake and groundwater rushes in and dilutes
00:13:38 --> 00:13:41 whatever arrived far below useful
00:13:41 --> 00:13:42 concentrations.
00:13:42 --> 00:13:44 Avery: Anslow's verdict is that it would have had to
00:13:44 --> 00:13:47 be a one in a million event, at best, a
00:13:47 --> 00:13:48 one off fluke.
00:13:48 --> 00:13:50 Anna: But here's the part I love.
00:13:50 --> 00:13:53 They ran the same numbers for Mars.
00:13:53 --> 00:13:56 And comets do about five times better there
00:13:56 --> 00:13:59 lower impact speeds because Mars is smaller
00:13:59 --> 00:14:02 and further from the sun and a much thinner
00:14:02 --> 00:14:03 atmosphere to filter them out.
00:14:04 --> 00:14:06 Avery: So if cometary delivery mattered for life
00:14:06 --> 00:14:09 anywhere in the inner solar system, Mars was
00:14:09 --> 00:14:12 the better target. Anslow puts it this
00:14:12 --> 00:14:15 in effect, it would be odd if it happened
00:14:15 --> 00:14:17 on Earth and not on Mars. Or
00:14:18 --> 00:14:20 perhaps more likely, it didn't happen on
00:14:20 --> 00:14:20 either.
00:14:21 --> 00:14:23 Anna: Pawyats this is modelling
00:14:24 --> 00:14:26 centred on one molecule. It doesn't rule
00:14:26 --> 00:14:29 comets out, and it says nothing against
00:14:29 --> 00:14:32 comets delivering water or other material.
00:14:32 --> 00:14:35 And Anslow's own earlier work found that in
00:14:35 --> 00:14:38 tightly packed planetary systems, comets can
00:14:38 --> 00:14:41 bounce between planets, slow down and deliver
00:14:41 --> 00:14:44 intact. So the answer may depend on
00:14:44 --> 00:14:44 the system.
00:14:44 --> 00:14:47 Avery: It pairs nicely with this week's other icy
00:14:47 --> 00:14:50 body stories and with episode 200's three
00:14:50 --> 00:14:51 floods at Jezero.
00:14:51 --> 00:14:54 If you're shopping for a place where life's
00:14:54 --> 00:14:56 chemistry got a delivery, Mars keeps looking
00:14:56 --> 00:14:57 interesting.
00:14:58 --> 00:15:00 Anna: Virgin Galactic is back.
00:15:01 --> 00:15:03 On Wednesday, the company named its first
00:15:03 --> 00:15:06 next generation space plane and on the same
00:15:06 --> 00:15:08 day flew it to its home base.
00:15:09 --> 00:15:12 Avery: The name is a, uh, Pyron, chosen in
00:15:12 --> 00:15:14 an online contest with votes from more than
00:15:14 --> 00:15:16 80 countries. It's Greek for
00:15:16 --> 00:15:19 boundless, and it's said aperon, not
00:15:19 --> 00:15:20 ape.
00:15:20 --> 00:15:20 Iron.
00:15:20 --> 00:15:23 Anna: Apeiron is the first Delta class ship.
00:15:23 --> 00:15:25 It was carried slung beneath the twin
00:15:25 --> 00:15:28 fuselage mothership eve on a 90 minute
00:15:28 --> 00:15:31 flight from the company's factory in Mesa,
00:15:31 --> 00:15:33 Arizona to Spaceport America in New
00:15:33 --> 00:15:36 Mexico. Teo Michael Cole Glaser summed
00:15:36 --> 00:15:39 up the day. This morning we gave Aiperon a
00:15:39 --> 00:15:39 name.
00:15:40 --> 00:15:42 This afternoon, 8 bron came home.
00:15:42 --> 00:15:44 Avery: The design principle hasn't changed since
00:15:44 --> 00:15:47 SpaceShipOne won the X Prize in 2004.
00:15:48 --> 00:15:50 Drop from the mothership at altitude, fire
00:15:50 --> 00:15:53 the rocket motor to the edge of space, then
00:15:53 --> 00:15:55 feather the wings to fall back stably before
00:15:55 --> 00:15:56 gliding to a Runway.
00:15:57 --> 00:16:00 Anna: The road here has been hard. The first
00:16:00 --> 00:16:02 SpaceShipTwo VSS Enterprise
00:16:02 --> 00:16:05 broke up in a test flight in 2014, killing
00:16:05 --> 00:16:06 one pilot.
00:16:07 --> 00:16:10 The second VSS Unity flew more than 30
00:16:10 --> 00:16:12 people, including Richard Branson, before its
00:16:12 --> 00:16:15 last commercial flight in 2024. The
00:16:15 --> 00:16:18 company then stopped flying to build this new
00:16:18 --> 00:16:18 class.
00:16:19 --> 00:16:21 Avery: The Delta ships are meant to be tougher and
00:16:21 --> 00:16:23 quicker to turn around. Better thermal
00:16:23 --> 00:16:26 protection, um, simpler maintenance. A target
00:16:26 --> 00:16:29 of two flights a week per ship and more than
00:16:29 --> 00:16:30 500 missions each.
00:16:31 --> 00:16:33 Anna: What's next? Software integration and
00:16:33 --> 00:16:36 validation. Then flight tests. Paying
00:16:36 --> 00:16:38 customers who've paid as much as
00:16:38 --> 00:16:41 US$750
00:16:41 --> 00:16:44 are due to fly from mid-2027. A
00:16:44 --> 00:16:46 second ship is already being built and should
00:16:46 --> 00:16:48 join in the second half of 2027,
00:16:48 --> 00:16:51 Avery: and the timing may suit them. Blue Origin
00:16:51 --> 00:16:54 paused New Shepard after its 17th crewed
00:16:54 --> 00:16:56 flight in January for at least two years
00:16:57 --> 00:16:59 to focus on the Moon. So if the schedule
00:16:59 --> 00:17:02 holds, Virgin could have suborbital tourism
00:17:02 --> 00:17:03 to itself for a while.
00:17:04 --> 00:17:06 Anna: As ever with spaceflight. If
00:17:07 --> 00:17:09 let move on to a few quick updates from
00:17:09 --> 00:17:10 today's news.
00:17:10 --> 00:17:13 Avery: Swift NASA's Swift Observatory ended
00:17:13 --> 00:17:16 operations on 20 October at about
00:17:16 --> 00:17:19 275 kilometres up and NASA says
00:17:19 --> 00:17:22 reentry is expected in the next few weeks.
00:17:22 --> 00:17:25 Tracking predictions currently point to early
00:17:25 --> 00:17:27 November. Most of it is expected to burn up.
00:17:28 --> 00:17:31 Swift caught thousands of gamma ray bursts in
00:17:31 --> 00:17:34 22 years, and the paper we covered on
00:17:34 --> 00:17:36 Monday, the burst with a split personality,
00:17:36 --> 00:17:37 was one of them.
00:17:37 --> 00:17:39 Anna: Hubble is helping Roman get ready.
00:17:40 --> 00:17:42 NASA has released a Hubble image of a
00:17:42 --> 00:17:44 gravitational lens catalogued as
00:17:44 --> 00:17:47 desi J194,
00:17:47 --> 00:17:50 where a galaxy about 4 1/2 billion light
00:17:50 --> 00:17:53 years away bends the light of a more distant
00:17:53 --> 00:17:55 one into an arc. And a counterarcing.
00:17:56 --> 00:17:58 Roman's wide survey should find around
00:17:58 --> 00:18:01 160 lenses like it. And
00:18:01 --> 00:18:03 Hubble's sharp single detector views are
00:18:03 --> 00:18:05 helping calibrate how Roman's images will
00:18:05 --> 00:18:08 look. This is an image release, not a new
00:18:08 --> 00:18:08 paper.
00:18:09 --> 00:18:12 Avery: And Starship SpaceX says Flight 15 is
00:18:12 --> 00:18:15 targeted for November with an attempt to
00:18:15 --> 00:18:17 catch both the booster and for the first
00:18:17 --> 00:18:20 time, the ship with the tower. Planning
00:18:20 --> 00:18:22 documents mention the 8th, but that's not an
00:18:22 --> 00:18:22 official date.
00:18:23 --> 00:18:26 Anna: Now let's go and find our haunted star.
00:18:26 --> 00:18:29 Betelgeuse sits at a declination of about
00:18:29 --> 00:18:32 plus 7 degrees, close to the celestial
00:18:32 --> 00:18:34 equator, which means this one is
00:18:34 --> 00:18:37 genuinely for everyone, north and south.
00:18:37 --> 00:18:40 Avery: Right now it's a late evening riser.
00:18:40 --> 00:18:42 On Friday night it comes up at about
00:18:42 --> 00:18:44 10:33pm in Sydney.
00:18:45 --> 00:18:47 9:48 in Los Angeles, 9, 9:46
00:18:47 --> 00:18:50 in New York and 8:39 in London.
00:18:51 --> 00:18:53 It's best before dawn, when it's highest,
00:18:53 --> 00:18:56 around 4:15 in the morning in Sydney, Los
00:18:56 --> 00:18:58 Angeles and New York, and about 3:20 in
00:18:58 --> 00:18:59 London.
00:18:59 --> 00:19:01 Anna: How high? Depends on where you are.
00:19:02 --> 00:19:04 About 49 degrees up from Sydney,
00:19:05 --> 00:19:07 63 from Los Angeles, 57
00:19:07 --> 00:19:10 from New York and 46 from London.
00:19:11 --> 00:19:14 And a reminder for North America, clocks fall
00:19:14 --> 00:19:17 back on Sunday 1st November. So from
00:19:17 --> 00:19:19 then on, all of those times arrive an hour
00:19:19 --> 00:19:21 earlier by the clock.
00:19:21 --> 00:19:24 Avery: From Australia, Orion is upside down.
00:19:24 --> 00:19:26 The belt is still of the three stars in a
00:19:26 --> 00:19:29 row, but the red shoulder Betelgeuse
00:19:29 --> 00:19:31 sits below it and blue white Rigel
00:19:31 --> 00:19:32 above.
00:19:32 --> 00:19:34 Northern. Listeners get the familiar version
00:19:34 --> 00:19:37 Betelgeuse at Upper left. Compare its
00:19:37 --> 00:19:40 orange with rigel's blue. That's
00:19:40 --> 00:19:43 30 kelvin. Against more than 10
00:19:43 --> 00:19:46 Anna: evening planets, Saturn is your
00:19:46 --> 00:19:49 easy one. After sunset, about 28 degrees
00:19:49 --> 00:19:52 up at dusk from Sydney, 15 from Los
00:19:52 --> 00:19:55 Angeles, 12 from New York and only
00:19:55 --> 00:19:58 six from London. Mercury is making
00:19:58 --> 00:20:00 its last appearance of this evening run and
00:20:00 --> 00:20:03 this one belongs to the south, about 11
00:20:03 --> 00:20:05 degrees up at sunset from Sydney against
00:20:06 --> 00:20:09 under four from the US and barely one from
00:20:09 --> 00:20:12 London. It's faint now, so binoculars
00:20:12 --> 00:20:14 and never sweep for it. Before the sun has
00:20:14 --> 00:20:14 fully set,
00:20:15 --> 00:20:17 Avery: the predawn sky is the north's turn.
00:20:18 --> 00:20:21 Mars and Jupiter are closing in six and a
00:20:21 --> 00:20:23 half degrees apart this weekend. Four by the
00:20:23 --> 00:20:25 5th of November and just over one degree on
00:20:25 --> 00:20:28 the 16th. Jupiter is the bright one,
00:20:28 --> 00:20:31 Mars the dimmer orange one beside it. At
00:20:31 --> 00:20:33 civil dawn they're 60 to 69 degrees
00:20:33 --> 00:20:36 up from the US, 50 odd from London and about
00:20:36 --> 00:20:37 30 from Sydney.
00:20:38 --> 00:20:40 Anna: The Moon helps out. It reaches last quarter
00:20:40 --> 00:20:43 on the 1st of November at 2028
00:20:43 --> 00:20:46 UTC, which is early Monday morning in Sydney.
00:20:46 --> 00:20:49 Before that it passes near Pollux in Gemini.
00:20:49 --> 00:20:52 Then in the Pre dawn of the 2nd and 3rd of
00:20:52 --> 00:20:55 November, it slides past Mars and Jupiter
00:20:55 --> 00:20:57 and then regulus, within about 2 degrees of
00:20:57 --> 00:20:58 regulus on the third.
00:20:59 --> 00:21:01 Avery: And with the Moon out of the evening sky
00:21:01 --> 00:21:04 after last quarter, it's a good week for
00:21:04 --> 00:21:06 zodiacal light, that faint cone of
00:21:06 --> 00:21:09 sunlight scattered by dust in the plane of
00:21:09 --> 00:21:09 the solar system.
00:21:10 --> 00:21:12 From the southern hemisphere it's in the west
00:21:12 --> 00:21:15 after dusk, the false dusk. From the north
00:21:15 --> 00:21:18 it's in the east before dawn. The false dawn
00:21:18 --> 00:21:21 dark sight, no Moon, and give your eyes 20
00:21:21 --> 00:21:22 minutes.
00:21:22 --> 00:21:25 Anna: Venus has just slipped past the sun
00:21:25 --> 00:21:28 into the morning sky, but it's still only a
00:21:28 --> 00:21:30 few degrees up. A dawn everywhere.
00:21:30 --> 00:21:31 Give it a couple of weeks.
00:21:32 --> 00:21:35 Avery: And our standing reminder, never look at the
00:21:35 --> 00:21:38 sun without proper protection for any solar
00:21:38 --> 00:21:40 viewing, including a partial eclipse, use
00:21:40 --> 00:21:42 only filters certified to ISO
00:21:42 --> 00:21:45 123122 and
00:21:45 --> 00:21:47 never through binoculars or a telescope
00:21:47 --> 00:21:49 unless the filter goes over the front.
00:21:50 --> 00:21:52 Anna: That's Astronomy AstroDailyPod for today. A,
00:21:52 --> 00:21:55 uh, haunted supergiant, crystals that
00:21:55 --> 00:21:57 went around the Moon, comets that probably
00:21:57 --> 00:22:00 didn't deliver life to Earth, and a new
00:22:00 --> 00:22:02 spaceship with a Greek name.
00:22:02 --> 00:22:04 Avery: If you head out before dawn this weekend,
00:22:04 --> 00:22:07 find Betelgeuse and remember there's a
00:22:07 --> 00:22:10 companion in there, hidden, stirring things
00:22:10 --> 00:22:10 up.
00:22:11 --> 00:22:14 It reappears in about a year and we'll be
00:22:14 --> 00:22:15 watching for it.
00:22:15 --> 00:22:18 Anna: You can find every episode, the show notes
00:22:18 --> 00:22:20 and our newsletter at astronomydaily
00:22:20 --> 00:22:23 IO and you can send us your question there
00:22:23 --> 00:22:25 too. Some of our best segments started as a
00:22:25 --> 00:22:28 listener question. We are AstroDaily Pod
00:22:28 --> 00:22:30 on Social Media, part of the Bites.com
00:22:30 --> 00:22:31 Podcast Network.
00:22:32 --> 00:22:33 Avery: I'm Avery.
00:22:33 --> 00:22:35 Anna: And I'm Anna. Clear skies and happy
00:22:35 --> 00:22:36 Halloween,
00:22:49 --> 00:23:00