Links & sources · University of Manchester — Astronomers use MeerKAT to directly detect faint hydrogen signal from the distant Universe — https://www.manchester.ac.uk/about/news/astronomers-use-meerkat-to-directly-detect-faint-hydrogen-signal-from-the-distant-universe · The Astrophysical Journal Letters — Paul, Wolz, Santos, Chen et al. (paper DOI) — https://doi.org/10.3847/2041-8213/ae808f · American Astronomical Society — release listing — https://aas.org/node/730547 · Phys.org — MeerKAT directly detects faint hydrogen signal from the distant universe — https://phys.org/news/2026-09-meerkat-faint-hydrogen-distant-universe.html · Space.com — Scientists detect signals of hydrogen from billions of years ago — https://www.space.com/astronomy/galaxies/scientists-detect-signals-of-hydrogen-from-billions-of-years-ago-could-this-help-us-map-out-the-universe · Xinhua — MeerKAT in South Africa directly detects faint hydrogen signal from distant universe — https://english.news.cn/africa/20260905/3f6c7164a4404b0a9b79f879b1d31a59/c.html · SKA Observatory — the construction journey (SKA-Mid, Karoo; SKA-Low, Murchison) — https://www.skao.int/en/explore/construction-journey · NASA Science — Roman's planet imager has powered on (1 September 2026) — https://science.nasa.gov/blogs/roman/2026/09/01/nasa-romans-planet-imager-has-powered-on/ · NASA — NASA's dark universe-seeking Nancy Grace Roman Space Telescope launches — https://www.nasa.gov/news-release/nasas-dark-universe-seeking-nancy-grace-roman-space-telescope-launches/ · Next Spaceflight — Starship Flight 14 (NET 15 September 2026, Pad 2, Starbase) — https://nextspaceflight.com/launches/details/8346/ · Tesla Oracle — FCC filing points to Starship Flight 14 on 15 September; Booster 21 33-engine static fire — https://www.teslaoracle.com/2026/09/02/fcc-filing-reveals-starship-flight-14-launch-on-september-15-spacex-conducts-33-engine-static-fire-on-booster-21/ · Nature — Tidal tomography reveals a thermal anomaly beneath Mars's crustal dichotomy (27 August 2026) — https://www.nature.com/articles/s41586-026-10893-x · Phys.org — Thermal anomaly discovered below Mars' south pole — https://phys.org/news/2026-08-thermal-anomaly-mars-south-pole.html · ESA — Latest updates: BepiColombo's arrival at Mercury — https://www.esa.int/Science_Exploration/Space_Science/BepiColombo/Latest_updates_BepiColombo_s_arrival_at_Mercury · ESA — BepiColombo's Mercury arrival begins (full replay) — https://www.esa.int/ESA_Multimedia/Videos/2026/09/BepiColombo_s_Mercury_arrival_begins_-_full_replay · Brown University — LZ experiment sees surprising result in search for dark matter — https://www.brown.edu/news/2026-09-01/lz-dark-matter-results · The LZ Dark Matter Experiment — collaboration site — https://lz.lbl.gov/ · ARC Centre of Excellence for Dark Matter Particle Physics — Stawell Underground Physics Laboratory — https://www.centredarkmatter.org/supl · University of Central Florida — UCF researchers study a centaur transforming into a comet — https://www.ucf.edu/news/ucf-researchers-study-a-centaur-transforming-into-a-comet/ · Phys.org — Saturn encounter may have set distant centaur on path to becoming a comet — https://phys.org/news/2026-09-saturn-encounter-distant-centaur-path.html · Space.com — Scientists watch a comet being born 3 billion miles away — https://www.space.com/astronomy/comets/scientists-watch-a-comet-being-born-3-billion-miles-away · Star Walk — Astronomical events in September 2026 — https://starwalk.space/en/news/night-sky-tonight-september · EarthSky — Venus greatest brilliancy, 18 September 2026 (magnitude −4.8) — https://earthsky.org/astronomy-essentials/venus-brightest-greatest-brilliancy-greatest-illuminated-extent-2/ · EarthSky — Sun news: flares, CMEs and aurora updates — https://earthsky.org/sun/sun-news-activity-solar-flare-cme-aurora-updates/ · Space.com — Night sky September 2026: the best things to see this month — https://www.space.com/stargazing/what-to-see-night-sky-september-2026 Follow us: @AstroDailyPod · astronomydaily.io
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This episode includes AI-generated content.
00:00:00 --> 00:00:03 Anna: Hey, everyone. Welcome back to Astronomy
00:00:03 --> 00:00:05 AstroDailyPod. And it's Saturday,
00:00:06 --> 00:00:07 so you know what that means.
00:00:08 --> 00:00:11 Avery: The weekend wrap one brand new storey,
00:00:11 --> 00:00:14 properly developed. And then we run back
00:00:14 --> 00:00:16 through the week's biggest news. In case you
00:00:16 --> 00:00:17 missed any of it,
00:00:18 --> 00:00:21 Anna: it's Saturday, September 5th, 2026.
00:00:21 --> 00:00:24 I'm Anna and this is series five, episode
00:00:24 --> 00:00:25 186.
00:00:26 --> 00:00:28 Avery: And, um, I'm Avery. Anna. Today's
00:00:28 --> 00:00:31 fresh storey is one I've been waiting years.
00:00:31 --> 00:00:34 Anna: Somebody to pull off a radio telescope in the
00:00:34 --> 00:00:37 Karoo desert has heard hydrogen. Not
00:00:37 --> 00:00:40 from one galaxy, from billions of them at
00:00:40 --> 00:00:43 once, 4 to 5 billion light years away.
00:00:43 --> 00:00:45 And it did it without any help from an
00:00:45 --> 00:00:47 optical telescope, which sounds modest
00:00:47 --> 00:00:49 Avery: until you understand that this particular
00:00:50 --> 00:00:52 signal is buried under a foreground about
00:00:52 --> 00:00:55 10 times brighter than it is.
00:00:55 --> 00:00:57 Anna: It's a technique people have been trying to
00:00:57 --> 00:01:00 make work for 15 years. This Week
00:01:00 --> 00:01:02 it worked. And it's a South African
00:01:02 --> 00:01:04 instrument that did it. With a strong
00:01:04 --> 00:01:06 Australian sequel coming.
00:01:07 --> 00:01:09 Avery: Then the week that was Roman
00:01:09 --> 00:01:11 opened its planet camera's eyes.
00:01:12 --> 00:01:15 Starship Flight 14 finally has a date on
00:01:15 --> 00:01:18 it. Mars turned out to be hotter underneath
00:01:18 --> 00:01:19 than anyone expected.
00:01:20 --> 00:01:23 Bepicolombo let go of the ride that got it to
00:01:23 --> 00:01:25 Mercury. A dark matter detector
00:01:25 --> 00:01:28 recorded one flash it cannot explain.
00:01:29 --> 00:01:31 Anna: And brand new this week. And genuinely
00:01:31 --> 00:01:34 lovely astronomers have watched a Comet
00:01:34 --> 00:01:37 switch on 3 billion miles away
00:01:37 --> 00:01:39 over five years in real time.
00:01:39 --> 00:01:41 Avery: Plus the sky for the week ahead. Both
00:01:41 --> 00:01:44 hemispheres. And it is a dark one
00:01:44 --> 00:01:45 in the good way.
00:01:46 --> 00:01:47 Anna: It's a big episode.
00:01:47 --> 00:01:48 Let's get into it.
00:01:49 --> 00:01:51 Avery: Right, start me at the beginning. Who did
00:01:51 --> 00:01:52 what?
00:01:52 --> 00:01:55 Anna: A team led by Dr. Surabh Paul. He's
00:01:55 --> 00:01:57 at the University of Manchester and the
00:01:57 --> 00:01:59 University of the Western Cape, working with
00:01:59 --> 00:02:02 Laura Wols at Jodrell Bank, Mario
00:02:02 --> 00:02:05 Santos at the Western Cape and Xiaoting
00:02:05 --> 00:02:08 Chen at Edinburgh. The paper is in the
00:02:08 --> 00:02:10 Astrophysical Journal Letters. And Manchester
00:02:10 --> 00:02:13 put the release out on Tuesday. It has been
00:02:13 --> 00:02:15 rolling through the international wires all
00:02:15 --> 00:02:17 week. Xinhua ran it yesterday.
00:02:18 --> 00:02:20 Avery: And the instrument is Meerkat.
00:02:20 --> 00:02:23 Anna: Meerkat 64 radio dishes standing
00:02:23 --> 00:02:26 in the Karoo in South Africa's Northern Cape,
00:02:26 --> 00:02:29 one of the quietest patches of radio sky on
00:02:29 --> 00:02:31 Earth. Which turns out to be the whole point.
00:02:31 --> 00:02:34 And Meerkat is not just a fine telescope in
00:02:34 --> 00:02:37 its own right. It's a precursor. It gets
00:02:37 --> 00:02:39 absorbed into ska mid the mid
00:02:39 --> 00:02:42 frequency half of the Square Kilometre Array.
00:02:42 --> 00:02:45 Avery: Okay, now tell me what they detected. Because
00:02:45 --> 00:02:48 hydrogen on its own doesn't sound like news.
00:02:49 --> 00:02:51 Anna: It isn't on its own. Hydrogen is
00:02:51 --> 00:02:54 the most common thing in the universe. The
00:02:54 --> 00:02:56 News is how they detected it and at what
00:02:56 --> 00:02:59 distance. Neutral hydrogen, a
00:02:59 --> 00:03:02 lone proton with a lone electron, emits
00:03:02 --> 00:03:04 at a very specific radio wavelength,
00:03:04 --> 00:03:06 21 centimetres.
00:03:06 --> 00:03:09 Avery: The famous 21 centimetre line.
00:03:09 --> 00:03:11 Anna: The famous one. And it's famous because it's
00:03:11 --> 00:03:14 reliable. Hydrogen doesn't care whether it's
00:03:14 --> 00:03:17 in a bright galaxy or a dim one. If it's
00:03:17 --> 00:03:19 neutral, it glows at 21 centimetres,
00:03:20 --> 00:03:23 which makes it, in principle, the perfect
00:03:23 --> 00:03:25 tracer for where matter actually is.
00:03:26 --> 00:03:27 Avery: In principle?
00:03:27 --> 00:03:30 Anna: In principle. In practise, the
00:03:30 --> 00:03:33 emission from any single distant galaxy is
00:03:33 --> 00:03:35 far too faint to pick out. So about 15
00:03:35 --> 00:03:37 years ago, people proposed a workaround
00:03:37 --> 00:03:40 called intensity mapping. Stop trying to
00:03:40 --> 00:03:43 resolve galaxies, point the telescope at a
00:03:43 --> 00:03:46 big patch of sky, deliberately blur it and
00:03:46 --> 00:03:48 measure the total 21 centimetre glow coming
00:03:48 --> 00:03:49 from that whole volume.
00:03:50 --> 00:03:52 Avery: So instead of a photograph of individual
00:03:52 --> 00:03:55 galaxies, you get what? A heat
00:03:55 --> 00:03:56 map.
00:03:56 --> 00:03:58 Anna: That's exactly the right image. A low
00:03:58 --> 00:04:01 resolution map of where the hydrogen is piled
00:04:01 --> 00:04:03 up and where it's thin. And because hydrogen
00:04:03 --> 00:04:06 sits inside galaxies and galaxies sit
00:04:06 --> 00:04:09 inside the cosmic web, that blurry map
00:04:09 --> 00:04:11 traces the large scale structure of the
00:04:11 --> 00:04:14 universe cheaply and over
00:04:14 --> 00:04:15 enormous volumes.
00:04:16 --> 00:04:18 Avery: Why does cheap matter? We have galaxy
00:04:18 --> 00:04:19 surveys.
00:04:19 --> 00:04:21 Anna: We do, and they're superb, but they're
00:04:21 --> 00:04:24 expensive in telescope time. To map
00:04:24 --> 00:04:26 structure optically, you have to identify
00:04:26 --> 00:04:28 each galaxy and measure its distance one at a
00:04:28 --> 00:04:31 time. Millions of them. Intensity
00:04:31 --> 00:04:33 mapping says, I don't need to know which
00:04:33 --> 00:04:36 galaxy is which, I only need to know how much
00:04:36 --> 00:04:39 hydrogen is in this cube of space versus that
00:04:39 --> 00:04:41 one. And if you can do that out to high
00:04:41 --> 00:04:44 redshift, you can measure how the universe
00:04:44 --> 00:04:46 has expanded, which is the dark energy
00:04:46 --> 00:04:46 question.
00:04:47 --> 00:04:49 Avery: So why hasn't anyone done it?
00:04:49 --> 00:04:51 Anna: Because of the foregrounds, and this is the
00:04:51 --> 00:04:54 part I want to be Precise about. The 21
00:04:54 --> 00:04:56 centimetre signal from those distant galaxies
00:04:56 --> 00:04:59 is extraordinarily faint. Sitting on top
00:04:59 --> 00:05:01 of it is radio emission from our own Milky
00:05:01 --> 00:05:03 Way synchrotron radiation,
00:05:04 --> 00:05:06 electrons spiralling in the galaxy's magnetic
00:05:06 --> 00:05:09 field. And that is roughly four orders of
00:05:09 --> 00:05:11 magnitude brighter than the thing you're
00:05:11 --> 00:05:12 trying to measure.
00:05:13 --> 00:05:14 Avery: 10 times.
00:05:15 --> 00:05:18 Anna: 10 times? Give or take. Then add human
00:05:18 --> 00:05:20 radio interference, satellites, aircraft,
00:05:20 --> 00:05:23 mobile networks, and then add the telescope's
00:05:23 --> 00:05:26 own quirks, which imprint themselves on the
00:05:26 --> 00:05:28 data in ways that look deceptively like
00:05:28 --> 00:05:30 signal. Paul's line in the release is the
00:05:30 --> 00:05:33 honest one. The signal is extremely faint and
00:05:33 --> 00:05:35 difficult to isolate from foreground
00:05:35 --> 00:05:38 emission, human made radio frequency
00:05:38 --> 00:05:40 interference and instrumental effects.
00:05:41 --> 00:05:43 Avery: So how have people got around that until now?
00:05:43 --> 00:05:45 Anna: By cheating slightly. And I mean that
00:05:45 --> 00:05:48 Admiringly, you take your radio map and you
00:05:48 --> 00:05:50 cross correlate it with an optical galaxy
00:05:50 --> 00:05:53 survey of the same patch of sky. You already
00:05:53 --> 00:05:55 know where the galaxies are from the optical
00:05:55 --> 00:05:58 data, so you ask, does the radio map get
00:05:58 --> 00:06:00 brighter in the places the optical survey
00:06:00 --> 00:06:01 says galaxies live?
00:06:01 --> 00:06:04 Avery: And if it does, that's the hydrogen.
00:06:04 --> 00:06:06 Anna: That's the hydrogen. It's a legitimate
00:06:06 --> 00:06:09 detection and Meerkat and its predecessors
00:06:09 --> 00:06:12 have done it before. But it has a built
00:06:12 --> 00:06:15 in limit. The foreground contamination
00:06:15 --> 00:06:18 and your instrumental noise don't know where
00:06:18 --> 00:06:20 the optical galaxies are. So they average
00:06:20 --> 00:06:23 away in the cross correlation, which is
00:06:23 --> 00:06:26 wonderful for confidence and useless if
00:06:26 --> 00:06:28 what you actually want is a standalone
00:06:28 --> 00:06:31 survey. You're always tethered to an
00:06:31 --> 00:06:32 optical telescope
00:06:33 --> 00:06:35 Avery: and, um, this week they cut the tether.
00:06:36 --> 00:06:38 Anna: This week they cut the tether.
00:06:39 --> 00:06:42 This is the 21 centimetre signal measured in
00:06:42 --> 00:06:45 the radio data alone. No
00:06:45 --> 00:06:47 optical survey propping it up. The
00:06:47 --> 00:06:50 foregrounds had to be genuinely removed
00:06:50 --> 00:06:53 rather than statistically dodged. And
00:06:53 --> 00:06:55 what's left is a real measurement of the
00:06:55 --> 00:06:56 hydrogen distribution.
00:06:57 --> 00:06:59 Avery: How much observing time did that take?
00:06:59 --> 00:07:02 Anna: Here's the part that made me sit up. About
00:07:02 --> 00:07:05 96 hours, four
00:07:05 --> 00:07:07 days of telescope time.
00:07:07 --> 00:07:08 Avery: That's nothing.
00:07:08 --> 00:07:11 Anna: And it gets better. Santos's quote is
00:07:11 --> 00:07:13 my favourite line in the whole release.
00:07:14 --> 00:07:17 It is particularly remarkable that the data
00:07:17 --> 00:07:19 used in this study were taken in 2018,
00:07:20 --> 00:07:22 when Meerkat had only just started science
00:07:22 --> 00:07:22 operations.
00:07:23 --> 00:07:25 Avery: Wait, the data is 8 years old?
00:07:26 --> 00:07:29 Anna: The data is 8 years old. This is not a new
00:07:29 --> 00:07:31 observing campaign. This is a brand new
00:07:31 --> 00:07:33 analysis of some of the first science data
00:07:33 --> 00:07:36 Meerkat ever took. And the advance is in
00:07:36 --> 00:07:39 the method, the foreground removal, the
00:07:39 --> 00:07:42 handling of the instrument's own systematics,
00:07:42 --> 00:07:44 the pipeline. The telescope was always
00:07:44 --> 00:07:46 capable, we weren't.
00:07:46 --> 00:07:48 Avery: How far back are we actually looking?
00:07:49 --> 00:07:51 Anna: The emission has been travelling 4 to 5
00:07:52 --> 00:07:54 billion years. So we're seeing the
00:07:54 --> 00:07:56 hydrogen as it was when the universe was
00:07:56 --> 00:07:59 around 9 billion years old, roughly a third
00:07:59 --> 00:08:02 of its present age ago, and well into the era
00:08:02 --> 00:08:05 when dark energy had taken over and the
00:08:05 --> 00:08:07 expansion was accelerating. That is
00:08:07 --> 00:08:09 exactly the epoch you want if you're trying
00:08:09 --> 00:08:12 to test how dark energy behaves over time.
00:08:12 --> 00:08:15 Avery: And the structures they're mapping are big,
00:08:15 --> 00:08:16 enormous.
00:08:17 --> 00:08:19 Anna: The scales involved are comparable to the gap
00:08:19 --> 00:08:22 between us and Andromeda millions of light
00:08:22 --> 00:08:24 years. Which is precisely the size range
00:08:24 --> 00:08:26 where the cosmic web's pattern lives.
00:08:27 --> 00:08:30 Avery: Alright, southern hemisphere angle. Because I
00:08:30 --> 00:08:32 know there is one and I know you're saving
00:08:32 --> 00:08:32 it.
00:08:33 --> 00:08:35 Anna: I am. And it's not a footnote, it's the
00:08:35 --> 00:08:38 entire future of this field. The
00:08:38 --> 00:08:41 Square Kilometre Array observatory is being
00:08:41 --> 00:08:44 built in two halves, both of them in the
00:08:44 --> 00:08:46 south. SKA Mid is going up in the
00:08:46 --> 00:08:49 Karoo alongside and incorporating meerkat
00:08:49 --> 00:08:52 itself. SKA Low is going up
00:08:52 --> 00:08:55 at Inuramana Ilgari Bundara, The
00:08:55 --> 00:08:58 CSIRO Murchison Radio Astronomy Observatory
00:08:58 --> 00:09:00 in Western Australia on Wajari
00:09:00 --> 00:09:01 Yamiji country.
00:09:02 --> 00:09:04 Avery: So this technique's proving ground and its
00:09:04 --> 00:09:07 future home are both in the Southern
00:09:07 --> 00:09:07 hemisphere.
00:09:07 --> 00:09:10 Anna: Both. And that's not an accident of
00:09:10 --> 00:09:13 politics. It's radio quietness
00:09:13 --> 00:09:16 and its geography. You cannot do
00:09:16 --> 00:09:19 this from a populated continent. The signal
00:09:19 --> 00:09:22 is too faint. You need somewhere with
00:09:22 --> 00:09:25 legally protected radio silence. And both
00:09:25 --> 00:09:27 the Karoo and the Murchison have exactly
00:09:27 --> 00:09:30 that. Wohls's line is the forward
00:09:30 --> 00:09:33 looking one. Meerkat continues to open
00:09:33 --> 00:09:36 new windows for cosmology and the point of a
00:09:36 --> 00:09:39 precursor is that everything you learn on it
00:09:39 --> 00:09:40 you carry across.
00:09:41 --> 00:09:44 Avery: So what does the SKA do with a working
00:09:44 --> 00:09:45 version of this?
00:09:45 --> 00:09:48 Anna: Surveys of a size that simply aren't
00:09:48 --> 00:09:50 available any other way. If
00:09:50 --> 00:09:53 96 hours on 64 dishes gets you a
00:09:53 --> 00:09:55 detection, then thousands of hours on an
00:09:55 --> 00:09:58 array with vastly more collecting area gets
00:09:58 --> 00:10:01 you a map. A three dimensional hydrogen map
00:10:01 --> 00:10:03 running across billions of years of cosmic
00:10:03 --> 00:10:06 time. Measuring the expansion history
00:10:06 --> 00:10:08 directly. That's a dark energy
00:10:08 --> 00:10:11 experiment done with radio waves from the
00:10:11 --> 00:10:12 southern half of the planet.
00:10:13 --> 00:10:16 Avery: And the honest caveat, because you always
00:10:16 --> 00:10:17 have one, two.
00:10:18 --> 00:10:21 Anna: First, this is a detection of the signal,
00:10:21 --> 00:10:23 not yet a precision cosmological measurement.
00:10:23 --> 00:10:26 The error bars are wide. And turning this
00:10:26 --> 00:10:28 into competitive constraints on dark energy
00:10:28 --> 00:10:30 is a longer road. Second,
00:10:30 --> 00:10:32 foreground removal is the kind of problem
00:10:32 --> 00:10:35 that has embarrassed radio astronomy before.
00:10:35 --> 00:10:38 The 21 centimetre cosmology field has had
00:10:38 --> 00:10:41 claimed detections walked back. The reason
00:10:41 --> 00:10:43 this one is being taken seriously is, is the
00:10:43 --> 00:10:46 cross correlation groundwork underneath it.
00:10:46 --> 00:10:48 They had already shown they could find the
00:10:48 --> 00:10:50 signal the safe way before they went looking
00:10:50 --> 00:10:51 for it the hard way,
00:10:52 --> 00:10:54 Avery: which is the right order to do things in.
00:10:55 --> 00:10:57 Anna: It's exactly the right order and it's why
00:10:57 --> 00:11:00 Paul's summary is the sentence to take away.
00:11:00 --> 00:11:03 Detecting it directly with meerkat shows that
00:11:03 --> 00:11:05 this technique is becoming a practical tool
00:11:05 --> 00:11:08 for cosmology. Not a promising
00:11:08 --> 00:11:10 idea anymore. Uh, a tool.
00:11:11 --> 00:11:11 Avery: Right?
00:11:11 --> 00:11:14 Monday to Friday, the six storeys that
00:11:14 --> 00:11:17 mattered and three of them have moved since
00:11:17 --> 00:11:18 we covered them.
00:11:18 --> 00:11:21 Anna: We start where we ended last weekend. The
00:11:21 --> 00:11:24 Nancy Grace Roman Space Telescope launched on
00:11:24 --> 00:11:27 Sunday, August 30th on a Falcon Heavy out of
00:11:27 --> 00:11:29 Launch Complex 39A. And it was
00:11:29 --> 00:11:32 clean, no anomalies. Straight up. Right
00:11:32 --> 00:11:34 on the money. We led Monday's episode with
00:11:34 --> 00:11:36 it, and that closed an ark we'd been building
00:11:36 --> 00:11:38 since 25 August.
00:11:39 --> 00:11:40 Avery: But it hasn't stopped being a storey.
00:11:41 --> 00:11:44 Anna: It hasn't. On Tuesday, NASA
00:11:44 --> 00:11:46 powered on the Roman Coronagraph instrument
00:11:46 --> 00:11:48 for the first time. It came alive between
00:11:48 --> 00:11:51 7:27 and 8:22 in the morning, Eastern
00:11:51 --> 00:11:54 time. That's the technology demonstration
00:11:54 --> 00:11:56 that blocks the light of a star so you can
00:11:56 --> 00:11:58 photograph the planets around it. Which is
00:11:58 --> 00:12:01 the hard part, absurdly hard. You're trying
00:12:01 --> 00:12:04 to see something a billion times fainter than
00:12:04 --> 00:12:06 the thing sitting right next to it. The
00:12:06 --> 00:12:09 coronagraph does it with masks, sensors
00:12:09 --> 00:12:12 and mirrors that flex themselves in real time
00:12:12 --> 00:12:14 to cancel out scattered starlight. And what
00:12:14 --> 00:12:17 it's after is a class of planet we've barely
00:12:17 --> 00:12:19 photographed, worlds that are older,
00:12:20 --> 00:12:23 colder and in closer orbits than the hot,
00:12:23 --> 00:12:25 young super Jupiters that direct imaging
00:12:25 --> 00:12:27 has managed so far.
00:12:27 --> 00:12:29 Avery: How long before it produces anything?
00:12:30 --> 00:12:32 Anna: Months. It goes into a long calibration
00:12:33 --> 00:12:35 campaign and its observing is spread across
00:12:35 --> 00:12:38 roughly three months of time inside the
00:12:38 --> 00:12:41 mission's first year and a half. So don't
00:12:41 --> 00:12:43 expect pictures soon. But the instrument is
00:12:43 --> 00:12:45 awake. And that's the milestone.
00:12:46 --> 00:12:49 Avery: On Tuesday, we led on Starship Flight 14.
00:12:49 --> 00:12:52 And the news then was that Booster 21
00:12:52 --> 00:12:55 had cleared its 33 engine static fire,
00:12:55 --> 00:12:58 and Ship 41's static fire was already
00:12:58 --> 00:13:01 done. What we could not give you was a date.
00:13:01 --> 00:13:02 Anna: And now there's one.
00:13:02 --> 00:13:05 Avery: There's one with a caveat I want to put up
00:13:05 --> 00:13:08 front. An FCC filing points to launch
00:13:08 --> 00:13:11 no earlier than September 15, and the
00:13:11 --> 00:13:13 launch trackers have moved to that date.
00:13:14 --> 00:13:16 SpaceX itself has not stood up and confirmed
00:13:16 --> 00:13:19 it. So net the 15th
00:13:19 --> 00:13:22 from Pad 2 at Starbase and treat it
00:13:22 --> 00:13:25 as a strong indication rather than a promise.
00:13:26 --> 00:13:27 Anna: And this is the big one.
00:13:27 --> 00:13:30 Avery: This is the big one on two counts. It's
00:13:30 --> 00:13:32 billed as the first genuinely orbital flight
00:13:32 --> 00:13:35 of starship. Previous test flights have flown
00:13:35 --> 00:13:38 trajectories that deliberately stopped short
00:13:38 --> 00:13:39 of orbit. So the vehicle came down
00:13:39 --> 00:13:42 regardless. And it carries the first ever
00:13:42 --> 00:13:45 attempt to catch the ship itself. Not the
00:13:45 --> 00:13:47 booster. The upper stage, back at the
00:13:47 --> 00:13:49 tower, into the arms.
00:13:49 --> 00:13:52 Anna: They've caught boosters repeatedly now they
00:13:52 --> 00:13:52 have,
00:13:52 --> 00:13:55 Avery: and it stopped being astonishing faster than
00:13:55 --> 00:13:57 it should have. But the ship is a different
00:13:57 --> 00:14:00 animal. It comes back from orbital velocity
00:14:01 --> 00:14:03 through the worst of the heating, and it has
00:14:03 --> 00:14:05 to arrive at a precise point with enough
00:14:05 --> 00:14:08 control authority left to be grabbed. If that
00:14:08 --> 00:14:10 works on the first try, it will be one of the
00:14:10 --> 00:14:13 more remarkable things this vehicle has done.
00:14:13 --> 00:14:16 And if it doesn't, then it's a test
00:14:16 --> 00:14:18 flight. And that's what test flights are for.
00:14:19 --> 00:14:21 Ten days out, weather and paperwork
00:14:21 --> 00:14:22 permitting.
00:14:22 --> 00:14:25 Anna: Wednesday's lead was the one I keep thinking
00:14:25 --> 00:14:28 about. A paper in nature published on
00:14:28 --> 00:14:30 August 27, led by Bern and
00:14:30 --> 00:14:33 colleagues, built out of years of accumulated
00:14:33 --> 00:14:35 radio tracking of three NASA
00:14:36 --> 00:14:39 Mars Global Surveyor, Mars Odyssey
00:14:39 --> 00:14:41 and the Mars Reconnaissance Orbiter.
00:14:41 --> 00:14:44 Avery: And the technique was the clever bit tidal
00:14:44 --> 00:14:45 tomography.
00:14:45 --> 00:14:48 Anna: The sun and Phobos flex Mars very slightly,
00:14:48 --> 00:14:50 and how much a planet flexes depends on how
00:14:50 --> 00:14:53 stiff it is inside. So if you track your
00:14:53 --> 00:14:55 orbiters precisely enough for long enough,
00:14:55 --> 00:14:58 the wobble in their orbits tells you about
00:14:58 --> 00:15:00 the rigidity of the rock rock beneath them.
00:15:00 --> 00:15:02 It's seismology without a seismometer.
00:15:03 --> 00:15:04 Avery: And what did it find?
00:15:04 --> 00:15:06 Anna: That the interior beneath the southern
00:15:06 --> 00:15:08 highlands is somewhere between 200
00:15:09 --> 00:15:11 and 400 degrees Celsius, hotter than the
00:15:11 --> 00:15:13 north and partially molten,
00:15:14 --> 00:15:17 which is not a small asymmetry. That's
00:15:17 --> 00:15:20 one planet with two different interiors.
00:15:20 --> 00:15:22 Avery: Does that explain anything?
00:15:22 --> 00:15:25 Anna: We've been stuck on potentially three
00:15:25 --> 00:15:27 things at once, which is why it's such a
00:15:27 --> 00:15:29 satisfying result. The crustal
00:15:29 --> 00:15:32 dichotomy. Why the southern highlands sit
00:15:32 --> 00:15:34 kilometres above the northern lowlands. The
00:15:34 --> 00:15:36 crustal magnetic anomalies, which are
00:15:36 --> 00:15:39 overwhelmingly a southern phenomenon. And a
00:15:39 --> 00:15:42 puzzle from Insight, where seismic waves were
00:15:42 --> 00:15:44 damped more than the models predicted. A
00:15:44 --> 00:15:47 hotter, partly molten south is a candidate
00:15:47 --> 00:15:48 answer to all three.
00:15:49 --> 00:15:51 Avery: And what caused it open?
00:15:51 --> 00:15:54 Anna: A giant impact early on? Lopsided
00:15:54 --> 00:15:57 convection in the mantle or a layer down
00:15:57 --> 00:15:59 there trapping heat? The paper doesn't pick
00:15:59 --> 00:16:01 one and I respect that.
00:16:01 --> 00:16:04 Avery: Moving on to Thursday and one of those quiet,
00:16:04 --> 00:16:06 irreversible moments. Bepi
00:16:06 --> 00:16:09 Colombo, the joint European and Japanese
00:16:09 --> 00:16:12 mission to Mercury separated from its Mercury
00:16:12 --> 00:16:14 transfer module on Wednesday the 3rd.
00:16:15 --> 00:16:17 Anna: Eight years to get to that point.
00:16:17 --> 00:16:20 Avery: Eight years and nine planetary flybys.
00:16:20 --> 00:16:23 Using gravity to shed speed because falling
00:16:23 --> 00:16:26 toward the sun is the easy part and arriving
00:16:26 --> 00:16:29 slowly enough to be captured is the hard
00:16:29 --> 00:16:31 part. The transfer module is the
00:16:31 --> 00:16:34 ion propulsion bus that did all that work,
00:16:34 --> 00:16:37 including working around a thruster power
00:16:37 --> 00:16:39 fault that forced the arrival to be
00:16:39 --> 00:16:42 redesigned. And once you let it go,
00:16:42 --> 00:16:43 you don't get it back.
00:16:44 --> 00:16:45 Anna: So what's the timeline now?
00:16:46 --> 00:16:48 Avery: Gravity capture at Mercury on November
00:16:48 --> 00:16:51 21st. Then the two orbiters
00:16:51 --> 00:16:54 go their separate ways. Japan's MIO is
00:16:54 --> 00:16:57 released around the 9th or 10th of December.
00:16:57 --> 00:17:00 Europe's Mercury Planetary Orbiter reaches
00:17:00 --> 00:17:03 its final Science orbit on 10 March
00:17:03 --> 00:17:06 next year and routine science begins on
00:17:06 --> 00:17:07 6 April.
00:17:07 --> 00:17:10 Anna: So this is the start of the arrival, not the
00:17:10 --> 00:17:10 end of the cruise.
00:17:11 --> 00:17:14 Avery: Precisely. And there are follow up, uh, beats
00:17:14 --> 00:17:17 all the way through this is a storey we'll be
00:17:17 --> 00:17:19 coming back to for the next seven months.
00:17:19 --> 00:17:22 Anna: And yesterday the storey with the biggest
00:17:22 --> 00:17:24 headlines and the smallest number attached to
00:17:24 --> 00:17:27 it. The LZ collaboration. Lux
00:17:27 --> 00:17:30 Zeppelin. 10 tonnes of liquid xenon
00:17:30 --> 00:17:32 a mile under South Dakota reported a
00:17:32 --> 00:17:35 single nuclear recoil event. They cannot
00:17:35 --> 00:17:37 explain in a place where
00:17:37 --> 00:17:40 Avery: dark matter could plausibly show up in
00:17:40 --> 00:17:43 Anna: exactly that place with essentially zero
00:17:43 --> 00:17:46 expected background. In 220 days
00:17:46 --> 00:17:48 of data from 2020, 2023 and
00:17:48 --> 00:17:51 2024, it was announced at TeV
00:17:51 --> 00:17:54 Particle Astrophysics in Chiba. Brown
00:17:54 --> 00:17:56 University released it on Tuesday and the
00:17:56 --> 00:17:58 paper has gone to Physical Review Letters.
00:17:59 --> 00:17:59 Avery: And the number?
00:18:00 --> 00:18:03 Anna: 2.6- Sigma globally, 3.4
00:18:03 --> 00:18:05 locally. Physics calls something a
00:18:05 --> 00:18:08 discovery at 5. So this is an anomaly.
00:18:09 --> 00:18:11 And to LZ's enormous credit, they have
00:18:11 --> 00:18:14 published it as an anomaly. Rick Gaitskill's
00:18:14 --> 00:18:16 line was that with only one event they are
00:18:16 --> 00:18:18 not claiming to have seen dark matter.
00:18:18 --> 00:18:20 Avery: If people take one thing from yesterday's
00:18:20 --> 00:18:23 Anna: episode, let it be the difference between
00:18:23 --> 00:18:25 local and global significance.
00:18:26 --> 00:18:28 Local asks how surprising the event is at
00:18:28 --> 00:18:30 one specific mass and energy.
00:18:31 --> 00:18:34 Global asks how surprising it is that you
00:18:34 --> 00:18:36 found something odd anywhere in the whole
00:18:36 --> 00:18:38 range you searched. Account for the size of
00:18:38 --> 00:18:41 the haystack and the surprise shrinks. That
00:18:41 --> 00:18:44 gap is the reason the honest number is 2.6
00:18:44 --> 00:18:46 and the southern angle
00:18:46 --> 00:18:47 Avery: briefly, because it's a good one.
00:18:48 --> 00:18:51 Anna: C upl the Stawell underground physics
00:18:51 --> 00:18:53 laboratory a kilometre down, a working gold
00:18:53 --> 00:18:56 mine in western Victoria and the only
00:18:56 --> 00:18:58 underground physics lab in the southern
00:18:58 --> 00:19:01 hemisphere. Its first experiment, Sabre
00:19:01 --> 00:19:04 south, installs late this year to test a 20
00:19:04 --> 00:19:06 year old Italian claim from Reversed Seasons,
00:19:07 --> 00:19:09 which is a genuinely elegant piece of
00:19:09 --> 00:19:09 experimental
00:19:09 --> 00:19:12 Avery: design and to finish something new that
00:19:12 --> 00:19:15 we didn't get to during the week. And it's my
00:19:15 --> 00:19:18 favourite thing on the list. Astronomers have
00:19:18 --> 00:19:20 watched a comet switch on,
00:19:20 --> 00:19:23 Anna: watched present tense over five
00:19:23 --> 00:19:23 years.
00:19:24 --> 00:19:26 Avery: The object is 450p
00:19:26 --> 00:19:29 lonios. It's a Centaur. And
00:19:29 --> 00:19:31 centaurs are uh, the in between population.
00:19:32 --> 00:19:35 I see bodies out among the giant planets that
00:19:35 --> 00:19:38 used to live in the Kuiper Belt and are on
00:19:38 --> 00:19:41 their way over enormous timescales to
00:19:41 --> 00:19:43 becoming the short period comets we
00:19:43 --> 00:19:43 recognise.
00:19:44 --> 00:19:47 Anna: So they're comets in waiting, comets in
00:19:47 --> 00:19:47 waiting.
00:19:47 --> 00:19:50 Avery: And normally we catch them at one end or the
00:19:50 --> 00:19:53 other. Catching one mid transition is
00:19:53 --> 00:19:55 rare. The work is out of the University
00:19:56 --> 00:19:58 of Central Florida, Charles Chambeau
00:19:58 --> 00:20:01 leading with Maria Womack, Yan
00:20:01 --> 00:20:04 Fernandez and Aaron Beck. And it's
00:20:04 --> 00:20:06 been accepted by the Planetary Science
00:20:06 --> 00:20:08 Journal released on Tuesday.
00:20:09 --> 00:20:10 Anna: How far out is it?
00:20:10 --> 00:20:13 Avery: Over 3 billion miles. And using
00:20:13 --> 00:20:16 the James Webb Space Telescope, together with
00:20:16 --> 00:20:18 Gemini North. They detected carbon
00:20:18 --> 00:20:21 dioxide gas, icy dust and
00:20:21 --> 00:20:24 thermal activity around it, and a coma that
00:20:24 --> 00:20:27 grows visibly across observations from
00:20:27 --> 00:20:29 2019 to 2024.
00:20:30 --> 00:20:32 Anna: So what's turning it on? It's nowhere near
00:20:32 --> 00:20:32 the Sun.
00:20:33 --> 00:20:36 Avery: It doesn't need to be. And this is the lovely
00:20:36 --> 00:20:38 bit of physics out in the cold.
00:20:38 --> 00:20:41 Water ice freezes into an amorphous form,
00:20:42 --> 00:20:45 disordered, glassy, with other gases
00:20:45 --> 00:20:47 trapped inside the structure. Warm it
00:20:47 --> 00:20:50 gently and it rearranges into proper
00:20:50 --> 00:20:53 crystalline ice. That transition
00:20:53 --> 00:20:55 releases the trapped gas, carbon
00:20:55 --> 00:20:58 dioxide, in this case, and that's what's
00:20:58 --> 00:20:59 blowing the coma out.
00:21:00 --> 00:21:02 Anna: And they can see that the ice has changed.
00:21:02 --> 00:21:04 Avery: They found crystalline water ice in the
00:21:04 --> 00:21:07 coma, which is the fingerprint. And a
00:21:07 --> 00:21:10 Saturn encounter appears to be what nudged
00:21:10 --> 00:21:12 the object onto the path that started warming
00:21:12 --> 00:21:15 it in the first place. So you get the whole
00:21:15 --> 00:21:18 causal chain. A gravitational nudge from
00:21:18 --> 00:21:21 a giant planet, a slow warming, a
00:21:21 --> 00:21:24 phase change in the ice, and a Comet is
00:21:24 --> 00:21:24 born
00:21:25 --> 00:21:27 Anna: 3 billion miles away. And we watched it
00:21:27 --> 00:21:27 happen.
00:21:28 --> 00:21:29 Avery: We watched it happen.
00:21:30 --> 00:21:32 Anna: Let's move on to our Skywatch segment. And
00:21:32 --> 00:21:34 this is a good week to actually get outside,
00:21:34 --> 00:21:36 because the Moon is getting out of the way.
00:21:36 --> 00:21:39 Last quarter was yesterday, Last quarter
00:21:39 --> 00:21:42 yesterday, and new Moon on Friday the
00:21:42 --> 00:21:45 11th. So every night this week, the Moon
00:21:45 --> 00:21:47 rises later and thinner and the evening
00:21:47 --> 00:21:50 sky is dark. If you have been putting off
00:21:50 --> 00:21:53 looking at something faint, this is the week.
00:21:53 --> 00:21:55 Avery: Southern hemisphere first.
00:21:55 --> 00:21:57 Anna: Southern hemisphere first, because September
00:21:57 --> 00:22:00 is our last really good month for it. From
00:22:00 --> 00:22:02 Sydney, the sun sets just before a quarter to
00:22:02 --> 00:22:05 six, and once it's properly dark, the centre
00:22:05 --> 00:22:07 of the Milky Way is almost directly overhead
00:22:08 --> 00:22:11 Sagittarius and Scorpius at the zenith.
00:22:11 --> 00:22:13 That means you're looking through the least
00:22:13 --> 00:22:16 atmosphere possible at the richest part of
00:22:16 --> 00:22:16 our galaxy.
00:22:17 --> 00:22:19 Avery: What do people actually point at?
00:22:19 --> 00:22:21 Anna: Find the teapot of Sagittarius with the naked
00:22:21 --> 00:22:24 eye and follow the steam up out of the spout.
00:22:25 --> 00:22:28 That's the galactic centre. Binoculars
00:22:28 --> 00:22:30 turn it into star clouds and dark dust lanes
00:22:30 --> 00:22:33 and the Lagoon Nebula. And a whole run of
00:22:33 --> 00:22:35 globular clusters are sitting right there.
00:22:36 --> 00:22:39 Then later in the evening, the Magellanic
00:22:39 --> 00:22:42 Clouds climb up in the Southeast, and 47
00:22:42 --> 00:22:45 Tucane is arguably the finest globular
00:22:45 --> 00:22:45 cluster in the sky.
00:22:46 --> 00:22:47 Avery: Planets down here.
00:22:47 --> 00:22:49 Anna: Venus low in the west after sunset.
00:22:50 --> 00:22:52 Brilliant, unmistakable, and building toward
00:22:52 --> 00:22:55 greatest Brilliancy on the 18th. At magnitude
00:22:55 --> 00:22:58 -4.8. Saturn is up most of
00:22:58 --> 00:23:01 the night in Aquarius, heading for opposition
00:23:01 --> 00:23:03 on October 4. And from the south, it
00:23:03 --> 00:23:05 rides far higher than it does for northern
00:23:05 --> 00:23:08 observers. And Jupiter is the pre dawn
00:23:08 --> 00:23:09 showpiece in the east.
00:23:10 --> 00:23:12 Avery: Anything to circle in the diary tomorrow
00:23:12 --> 00:23:13 morning?
00:23:13 --> 00:23:16 Anna: Sunday the 6th, a thin waning crescent
00:23:16 --> 00:23:18 moon sits a few degrees from Mars in the
00:23:18 --> 00:23:21 predawn sky. A nice one for a phone camera.
00:23:21 --> 00:23:23 Monday the Moon moves on to Pollux
00:23:24 --> 00:23:26 Avery: and North America gets the proper event.
00:23:27 --> 00:23:29 Anna: Tuesday the 8th, the moon occults uh,
00:23:29 --> 00:23:32 Jupiter. The planet passes behind the lunar
00:23:32 --> 00:23:34 disc. The footprint covers Canada,
00:23:35 --> 00:23:38 Greenland, the United States, eastern
00:23:38 --> 00:23:40 Russia and the North Pacific. And for much
00:23:40 --> 00:23:43 of eastern North America it happens after
00:23:43 --> 00:23:45 sunrise in broad daylight.
00:23:45 --> 00:23:46 Avery: Daylight.
00:23:46 --> 00:23:49 Anna: Daylight. And that brings the standing
00:23:49 --> 00:23:51 reminder which applies directly here. If
00:23:51 --> 00:23:53 you are observing anywhere near the sun,
00:23:54 --> 00:23:57 hunting Jupiter in a bright sky or looking at
00:23:57 --> 00:23:59 the sunspots. I'm about to mention any filter
00:23:59 --> 00:24:02 you use for direct solar viewing must be
00:24:02 --> 00:24:03 certified to the ISO
00:24:03 --> 00:24:06 123122 standard.
00:24:07 --> 00:24:10 Not sunglasses, not welding glass of unknown
00:24:10 --> 00:24:13 grade, not smoked glass, not a phone screen,
00:24:13 --> 00:24:14 ISO
00:24:14 --> 00:24:17 123122 and
00:24:17 --> 00:24:19 cheque. The certification is genuine.
00:24:19 --> 00:24:21 Sweeping binoculars or a telescope across a
00:24:21 --> 00:24:24 daylight sky is exactly how people injure
00:24:24 --> 00:24:27 themselves permanently. And it takes a
00:24:27 --> 00:24:28 fraction of a second.
00:24:28 --> 00:24:29 Avery: Meteors.
00:24:29 --> 00:24:32 Anna: The September Epsilon Perseids peak on
00:24:32 --> 00:24:34 Wednesday the 9th. A modest shower,
00:24:34 --> 00:24:37 about eight an hour at best. And it's a
00:24:37 --> 00:24:39 northern hemisphere event with the radiant in
00:24:39 --> 00:24:42 Perseus. But it falls two nights before
00:24:42 --> 00:24:44 New Moon. So if you're up north and you're
00:24:44 --> 00:24:46 out anyway, conditions are as good as that
00:24:46 --> 00:24:49 shower ever gets. And the sun itself
00:24:50 --> 00:24:52 busier than last weekend. Active Region
00:24:52 --> 00:24:55 4524 has come back around the
00:24:55 --> 00:24:58 limb and fired an M M1 2 flare
00:24:58 --> 00:25:01 at 6 7:45 universal time. Yesterday,
00:25:01 --> 00:25:04 with a brief radio blackout, Region
00:25:04 --> 00:25:07 4523 is growing and throwing C class
00:25:07 --> 00:25:10 flares. Nothing is aimed squarely at us.
00:25:10 --> 00:25:12 The strongest eruption went well away from
00:25:12 --> 00:25:14 Earth. Aurora chances
00:25:15 --> 00:25:17 honest answer quiet tonight,
00:25:17 --> 00:25:20 possibly unsettled. Sunday into Monday
00:25:20 --> 00:25:23 KP3.4 at best that's a high
00:25:23 --> 00:25:26 latitude show. Only Tasmania and southern
00:25:26 --> 00:25:28 New Zealand down here, Scotland and Alaska up
00:25:28 --> 00:25:31 there. Watch the space weather feeds rather
00:25:31 --> 00:25:32 than the headlines.
00:25:32 --> 00:25:34 Avery: And one for northern binoculars.
00:25:35 --> 00:25:37 Anna: The Double Cluster in Perseus. While the
00:25:37 --> 00:25:40 moon's away, naked eye, it's a smudge.
00:25:40 --> 00:25:43 In binoculars it's two open clusters side by
00:25:43 --> 00:25:45 side in one field. And it's one of the best
00:25:45 --> 00:25:46 sights in the sky.
00:25:47 --> 00:25:49 Avery: And that's the weekend wrap for Saturday
00:25:49 --> 00:25:52 September 5th. A radio telescope in
00:25:52 --> 00:25:55 the Kourou has mapped hydrogen across
00:25:55 --> 00:25:58 4 to 5 billion light years using
00:25:58 --> 00:26:01 nothing but radio waves and proved out
00:26:01 --> 00:26:03 the technique the Square Kilometre Array will
00:26:03 --> 00:26:06 use to measure dark energy from the southern
00:26:06 --> 00:26:07 hemisphere.
00:26:07 --> 00:26:10 Anna: Roman's coronagraph is awake. Starship
00:26:10 --> 00:26:13 Flight 14 is pencilled in for the 15th with
00:26:13 --> 00:26:16 the first attempt to catch a ship. Mars is
00:26:16 --> 00:26:18 hotter underneath its southern half than
00:26:18 --> 00:26:20 anyone expected. BepiColombo has let go
00:26:20 --> 00:26:23 of its transfer module and is falling toward
00:26:23 --> 00:26:25 Mercury. A xenon detector under South
00:26:25 --> 00:26:28 Dakota has one flash it can't explain and is
00:26:28 --> 00:26:30 being admirably careful about it.
00:26:30 --> 00:26:33 Avery: And a centaur 3 billion miles away
00:26:33 --> 00:26:36 has spent five years quietly turning into a
00:26:36 --> 00:26:37 comet while we watched.
00:26:38 --> 00:26:41 Anna: Full show notes Links to every primary source
00:26:41 --> 00:26:43 and the whole back catalogue are at
00:26:43 --> 00:26:44 astronomydaily IO.
00:26:45 --> 00:26:47 Avery: You'll find us on X Instagram and
00:26:47 --> 00:26:50 TikTok@astrodaily pod. And if
00:26:50 --> 00:26:52 you've got a question or a correction, we
00:26:52 --> 00:26:55 want it. There's a contact form on the
00:26:55 --> 00:26:55 website.
00:26:56 --> 00:26:58 Anna: If today's episode was useful, the single
00:26:58 --> 00:27:01 most helpful thing you can do is send it to
00:27:01 --> 00:27:03 one person who'd enjoy it.
00:27:03 --> 00:27:06 Avery: We're back Monday with the regular weekday
00:27:06 --> 00:27:06 format.
00:27:07 --> 00:27:09 Anna: Until then, the moon's out of the way all
00:27:09 --> 00:27:11 week. Get outside. Clear skies,
00:27:12 --> 00:27:13 Clear skies.