Aug. 20, 2026
LandSpace Nails It: China's First Private Booster Recovery
Anna and Avery cover LandSpace becoming the first Chinese commercial company to land an orbital-class rocket booster — a big step for the country's private space sector. Plus: astronomers find a "mega-Earth" 23 times more massive than our planet that shouldn't be able to exist, a star weaving impossibly close to our galaxy's supermassive black hole that could reveal its spin within a decade, and new JWST data showing the early universe's galaxies were hiding roughly four times more mass than we thought. Full show notes: Today's episode — S05E172, Thursday August 20, 2026: Main story: China's private spaceflight sector sticks the landing. On August 19, Chinese commercial launch company LandSpace successfully recovered the first stage of its Zhuque-3 (ZQ-3) rocket after liftoff from the Dongfeng Commercial Space Innovation Pilot Zone in northwestern China — the first time any Chinese commercial company has landed an orbital-class booster. The 76.6-metre, stainless-steel, methane-fueled rocket (taller than a Falcon 9) touched down on four legs roughly 390km downrange in Gansu Province about eight minutes after liftoff, running on a single Tianque-12 engine. It's ZQ-3's second flight — the first, in December 2025, reached orbit but couldn't stick the recovery. The landing puts LandSpace among a very small club of companies with proven booster-reuse technology and marks, in the company's words, a shift "toward the engineering application phase of reusability." A "mega-Earth" that shouldn't be this dense. Astronomers led by Max Kroft (University of Wisconsin–Madison) have identified GJ 523b, a rocky exoplanet 23.5 times more massive than Earth but only 2.5 times its width — extraordinarily dense for its size. Standard planet-formation models say a planet this massive, orbiting its star every 17.75 days in a system just 170 million years old, should have pulled in a thick hydrogen-helium envelope; instead it's stayed almost entirely rocky. Found by TESS and confirmed with the WIYN 3.5-metre telescope at Kitt Peak; submitted to The Astronomical Journal, not yet peer-reviewed. The star that could reveal a black hole's spin. A newly identified star, S301, is orbiting our galaxy's central supermassive black hole, Sagittarius A*, closer and faster than any star found before it — passing within 12 astronomical units at roughly 25,000 kilometres per second and completing a full orbit in just 8.7 years. Led by K. Abd El Dayem (Paris Observatory) with Nobel laureate Reinhard Genzel's group, researchers expect to use S301's orbit to directly measure the black hole's spin within a decade — a first for any supermassive black hole, and a real-world test of Einstein's general relativity. JWST finds the early universe's galaxies were hiding their mass. A team led by Chloe Cheng (Leiden University), using JWST's NIRSpec instrument alongside data from the VLT's LEGA-C survey, found that ancient "quiescent" galaxies contain far more faint, low-mass stars than previously accounted for — potentially raising their true mass estimates by a factor of four. The hidden stars had simply been outshone by brighter ones in the same galaxies. Published in Nature Astronomy; the finding deepens existing tension with current galaxy-formation models. Tonight's sky: the Moon is about 56% illuminated and well-placed for lunar observing — look along the sunrise terminator for the crater Theophilus and its dramatic, shadowed walls. Venus is still blazing at magnitude -4.1 low in the western sky after sunset, and Saturn continues its predawn "moon parade" in the south-southeast for early risers. Links & sources: - Spaceflight Now — LandSpace becomes first commercial Chinese company to land an orbital-class booster - Space.com — Touchdown! Private Chinese rocket aces landing on 2nd-ever flight - NASASpaceFlight.com — Zhuque-3 Completes Second Flight with Successful First-Stage Landing - Space.com — Astronomers discover a giant, rocky 'mega-Earth' 23 times more massive than our planet - Phys.org — Mega-Earth GJ 523b is 23 times as massive as our planet—but only 2.5 times as wide - Universe Today — The Fastest Star in the Milky Way Will Test Relativity - Universe Today — Whoa! The JWST's Ancient Galaxies Are Much More Massive Than Thought - Space.com — Night sky August 2026: what you can see tonight Follow us: @AstronomyDailyPod
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This episode includes AI-generated content.
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Anna: Hey, everyone. Welcome back to Astronomy
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Daily. I'm Anna.
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Avery: And I'm, um, avery. It's Thursday, August
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20th, series five, episode
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Anna: 172, and we're leading with a genuine
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milestone today.
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China's commercial space sector just proved
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it can land a rocket, not just launch one.
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Avery: Landspace sticks. The landing on Zoo Q3.
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First time any Chinese private company has
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pulled that off.
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Anna: Then a, uh, planet that's somehow 23 times
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heavier than Earth while barely being any
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bigger, which really shouldn't be possible.
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A star doing laps around our galaxy's
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supermassive black hole. Faster and closer
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than anything we've ever tracked. And new
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James Webb data suggesting the early universe
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has been hiding a huge chunk of its mass from
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us this whole time.
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Avery: Plus tonight. Good excuse to actually get the
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telescope out and look at some craters.
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Anna: Lots to get through. Let's get into it.
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Avery: Okay, so China and rockets. We were just
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talking about this two episodes ago, right?
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The Long March failure and the fast recovery.
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Anna: Right. But this is a completely different
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story and honestly a bigger one. Long term.
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That was China's state space program. Long
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March rockets run by the state owned main
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contractor. This is China's commercial
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sector. And specifically a company called
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Landspace.
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Avery: Which does what exactly?
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Anna: Landspace was founded back in 2015, one of
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the first wave of Chinese private launch
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companies. Their rocket is called Zhuque 3
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or ZQ3, and it's a big one.
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Stainless steel construction, liquid methane
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propulsion, standing 76.6
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meters tall. For comparison, a Falcon 9
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is about 70 meters. This thing is taller
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than what SpaceX flies.
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Avery: So already an ambitious vehicle before you
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even get to the landing.
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Anna: Exactly. And landing is the part that matters
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here. Zoo K3 flew for the first time back in
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December 2025. That flight actually
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reached orbit successfully, which is already
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a big deal for a new rocket. But the landing
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attempt on the first stage didn't work out.
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Avery: So this was the do over.
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Anna: This was the do over. And yesterday, August
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19th, they nailed it. Liftoff was from the
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Dongfang Commercial Space Innovation Zone in
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northwestern China. And about eight minutes
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after launch, the first stage came down on
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four landing legs, roughly
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390km downrange, out
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in Minquin County, Gansu Province. It
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came in on a single Tiem Kwei 12 engine.
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Touched down close to dead center on the pad.
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Avery: Eight minutes from launch to landing. That's
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a very SpaceX shaped timeline.
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Anna: It's the same basic playbook. Yeah. Boost,
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separate, flip, come back down under power.
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Nobody outside SpaceX had made that work on
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an orbital class booster with actual
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repeatability. Until now. There have been a
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couple of smaller Chinese hop tests and
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suborbital attempts from other companies, but
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landing an orbital class booster on a real
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orbital mission is a different tier of
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difficulty.
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Avery: What does Landspace actually get from one
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successful landing? Is the booster flying
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again next week?
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Anna: Not next week, no. This is very much a prove
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the concept flight rather than a, uh, ready
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for daily reuse flight. But it's the step
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everything else depends on. Landspace
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themselves are, uh, framing it as moving
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toward the engineering application phase of
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reusability. In other words, this is where
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you stop asking can this work at all? And
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start asking how do we make this routine?
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Avery: Any hiccups? These things usually aren't
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perfectly clean.
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Anna: The core landing itself was clean, legs
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deployed, touched down where it was supposed
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to. Some reporting mentioned activity in the
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aft section of the booster after landing,
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which, given this is methane fueled hardware
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coming down hot isn't unheard of even on
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successful landings. SpaceX has had post
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landing fires on otherwise successful Falcon
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9 recoveries too. It doesn't take away from
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the fact that the vehicle landed intact and
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upright.
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Avery: So bottom line, why should our listeners care
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about one Chinese company landing one
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rocket?
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Anna: Because reusability is the thing that
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actually changes the economics of
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spaceflight. It's why Falcon 9 turned SpaceX
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from one very good rocket company into the
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company that now launches more than anyone
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else multiple times a week. China's had
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a state level reusable rocket effort in
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progress for years, but this is the first
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time a private Chinese company has shown it
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can do the hardest part. Landspace just put
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itself in what's genuinely a very short list
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of organizations on Earth that have landed an
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orbital class booster.
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Avery: A list that's about to get a
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Anna: little more competitive, which is good for
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everyone watching prices honestly.
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Next up, over to exoplanets and a
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planet that's breaking the rules just by
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existing.
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Avery: Go on.
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Anna: It's called GJ523B.
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Team led by Max Croft at the University of
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Wisconsin Madison, found it using NASA's
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TESS spacecraft, then confirmed it with
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follow up observations from the Wynn
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3.5-meter telescope at Kitt Peak in
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Arizona. Here's the number that makes it
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interesting. This planet is 23
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and a half times the mass of Earth.
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Avery: Okay, so a mini Neptune gas envelope
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and all.
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Anna: That's exactly what you'd expect. And that's
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exactly what it isn't. It's only about 2 1/2
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times Earth's width. Do that math. 23
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times the mass in barely 2 1/2 times the size
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and you get something extremely den and
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as far as they can tell, mostly rock. Not a
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puffed up gas world at all.
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Avery: Why is that a problem?
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Anna: Because planet formation models are pretty
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clear on this. Once a rocky core gets big
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enough and 23 earth masses is well past
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that threshold, it should have enough gravity
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to grab a thick hydrogen helium atmosphere
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from the disk of gas around its young star
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and balloon outward the way Neptune or Uranus
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did. DJ523B had
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every opportunity to do that. It orbits its
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star every 17.75 days
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and the whole system is only about 170
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million years old. Young enough that there
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should have still been plenty of gas around
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when it formed.
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Avery: And instead it just didn't bother.
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Anna: Instead it just stayed rock all the way up to
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23 earth masses. Croft's own quote on
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it was this isn't what we expected at all.
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Which for a planetary scientist is basically
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Avery: shouting, so what's the explanation?
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Anna: Honestly, right now they don't fully have
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one. Maybe it formed somewhere else closer
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in, in a gas poor environment and never had
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the chance to accrete an atmosphere. Maybe it
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did have one and something stripped it away
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early. That's the appeal of finding it. It's
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a genuine outlier that doesn't fit the
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models, which usually means there's a piece
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of planet formation physics we're still
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missing. I'll flag this result's been
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submitted to the Astronomical Journal, but
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hasn't gone through peer review yet. So
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consider it an exciting first look rather
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than a settled result.
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Avery: The universe's way of telling planetary
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scientists they're not done yet.
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Anna: It never is.
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Avery: Alright, this next one is genuinely one of my
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favorite kinds of stories. Extreme physics,
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extreme numbers.
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Anna: You're going to like this. Then there's a
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star newly cataloged as S301
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that's been found orbiting Sagittarius A,
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the supermassive black hole at the center of
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our own galaxy.
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Avery: We've talked about the S stars before, right?
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The ones that whip around Sagittarius A on
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tight orbits we have.
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Anna: And S301 just took the crown from all
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of them. It gets within 12 astronomical
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units of the black hole at closest approach.
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That's closer than any star ever tracked
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around. Sagittarius A, moving at, uh, roughly
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25,000 kilometers per second. And
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it completes one full orbit in just
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8.7 years.
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Avery: 8.7 years to loop around the
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supermassive black hole. For comparison,
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Jupiter takes about 12 years just to go
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around our sun, right?
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Anna: And Sagittarius a is about 4
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million times the mass of our Sun. So The
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Physics Environment S301 is living in
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is nothing like anything in our solar system.
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This was found by a team led by K. Abdel
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Diam at the Paris Observatory, working with
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Felix Meng and Stephan Gillison at the Max
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Planck Institute, Juana Sorno at Paris
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psl and the broader collaboration is directed
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by Reinhard Genzel, Nobel Laureate for his
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work proving Sagittarius A is a
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supermassive black hole in the first place.
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Avery: So why does one extreme star matter
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beyond just being a cool record breaker?
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Anna: Because an orbit this tight and this precise
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becomes a physics instrument. General
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relativity predicts that a, uh, spinning
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massive object drags spacetime around with
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it. It's called the lens theoring effect,
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or frame dragging. We've measured tiny
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versions of this effect around Earth with
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satellites. Nobody has ever directly
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measured it around a, uh, supermassive black
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hole because you need a star orbiting close
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enough, fast enough and predictably enough
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to detect the tiny relativistic wobble it
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causes.
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Avery: And S301 threads that needle.
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Anna: That's the hope. The team thinks that with
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continued observation, they could measure
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Sagittarius A's actual SP
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within a decade. That would be the first
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direct spin measurement of any supermassive
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black hole anywhere. Not modeled,
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not inferred from surrounding gas.
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Measured from watching a star get pushed
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around by the black hole, literally dragging
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space itself.
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Avery: A, uh, decade's a long wait, but that's a
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hell of a payoff.
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Anna: Worth the patience.
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Alright, moving on to our last story before
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we get to tonight's sky. And this one's a
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quiet result that could have a pretty loud
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effect on cosmology.
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Avery: How loud are we talking?
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Anna: Up to four times loud. A team led by
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Chloe Chang at Leiden University looked at
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nine quiescent galaxies, meaning galaxies
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that have basically stopped forming new
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stars. Sitting at a redshift of about
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0.7, they used James Webb's
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NIR SPECT instrument, combined with data from
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the Very Large Telescope's LEGA survey to
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look really closely at the actual population
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of star stars inside these galaxies
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and found something we'd been missing. A lot
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of something. Turns out these galaxies
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contain far more faint, low mass stars
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than anyone had accounted for. They'd simply
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been outshone and hidden by the smaller
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number of bright stars in the same galaxies.
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Once you properly count the dim ones, the
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true stellar mass of these galaxies goes up
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by something like a factor
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Avery: of four, four or times the mass.
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Just hiding in plain sight.
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Anna: Hiding in Plain sight. And it wasn't random.
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Which galaxies had the most hidden mass
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either. The oldest galaxy in the sample,
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one that started forming stars less than 500
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million years after the Big Bang, had the
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largest hidden population of low mass stars.
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Avery: Why would older galaxies hide more mass
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specifically?
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Anna: That's the open question, and it's a
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genuinely important one, because it means the
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ratio of small stars to big stars. What
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astronomers call the initial mass function
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might not be the same constant everywhere and
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everywhen, the way models have generally
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assumed. If early galaxies
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systematically formed proportionally more low
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mass stars, every mass estimate we've made
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for the early universe using the standard
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assumption could be off.
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Avery: Which affects a lot more than just these nine
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galaxies.
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Anna: Right. It touches how we calculate galaxy
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masses across basically all of early universe
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cosmology. And there's a nice side effect
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too. More low mass stars means more
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potential hosts for rocky Earth sized
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planets in the early universe. This was
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published in Nature Astronomy under the very
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on the nose title, Hidden Mass in Early
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Galaxies Revealed by bottom, Heavy initial
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Mass Functions.
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Avery: The early universe just got a lot more
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crowded and a lot heavier in one paper.
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Anna: Webb keeps doing that to cosmology this year.
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Avery: All right, let's get people outside tonight.
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What are we looking at?
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Anna: Grab a telescope if you've got one, because
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tonight's, uh, a genuinely good moon night.
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It's about 56% illuminated right now, and
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if you look right along the sunrise
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terminator, that line between lit and
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shadowed, you'll find the crater Theophilus
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down along Mare Nectaris.
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Avery: What makes that one worth hunting down?
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Anna: Specifically, with the sun that low on it,
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the shadows are dramatic. You get
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Theophilus, sharp, heavily terraced walls,
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seamless standing out in real relief. Plus a
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big multi pointed central peak casting its
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own shadow. It's one of those craters that
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actually looks three dimensional through a
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scope tonight instead of just a flat circle.
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Avery: And um, for anyone without a telescope
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Anna: handy, step outside right after sunset and
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look west. Venus is still an absolute
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beacon out there at, ah, magnitude minus 4.1,
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easily the brightest thing in the sky besides
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the Moon. And if you're an early riser,
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Saturn's moon parade that we mentioned last
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episode is still running in the south
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southeast before dawn. Titan, Rhea,
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Tethys, Dion, all still lined up
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thanks to those unusually narrow, nearly
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edge on rings.
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Avery: Good night to actually use the equipment
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instead of letting it collect dust.
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Anna: Always is.
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And that's it for Today's episode. Series
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five, episode 172 in the
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books.
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Avery: Quick recap. Plan space makes history.
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Landing Z3's booster, a mega
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Earth that refuses to follow the rules, a
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star that might let us finally measure a
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black hole spin. Um, and James Webb showing
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us the early universe was heavier than we
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thought all along.
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Anna: If you enjoyed the show, the best thing you
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can do is tell a friend. Leave us a rating
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wherever you listen, and follow us on the
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socials at astrodaily Pod for updates between
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episodes. And of course, check out our
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website at astronomydaily IO for further
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details on all of these stories.
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Avery: We'll be back tomorrow with more from across
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the universe.
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Anna: Until then, keep looking up Clear
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skies, everyone.
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Sam mhm.
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Anna: Hey, everyone. Welcome back to Astronomy
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Daily. I'm Anna.
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Avery: And I'm, um, avery. It's Thursday, August
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20th, series five, episode
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Anna: 172, and we're leading with a genuine
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milestone today.
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China's commercial space sector just proved
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it can land a rocket, not just launch one.
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Avery: Landspace sticks. The landing on Zoo Q3.
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First time any Chinese private company has
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pulled that off.
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Anna: Then a, uh, planet that's somehow 23 times
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heavier than Earth while barely being any
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bigger, which really shouldn't be possible.
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A star doing laps around our galaxy's
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supermassive black hole. Faster and closer
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than anything we've ever tracked. And new
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James Webb data suggesting the early universe
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has been hiding a huge chunk of its mass from
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us this whole time.
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Avery: Plus tonight. Good excuse to actually get the
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telescope out and look at some craters.
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Anna: Lots to get through. Let's get into it.
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Avery: Okay, so China and rockets. We were just
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talking about this two episodes ago, right?
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The Long March failure and the fast recovery.
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Anna: Right. But this is a completely different
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story and honestly a bigger one. Long term.
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That was China's state space program. Long
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March rockets run by the state owned main
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contractor. This is China's commercial
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sector. And specifically a company called
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Landspace.
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Avery: Which does what exactly?
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Anna: Landspace was founded back in 2015, one of
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the first wave of Chinese private launch
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companies. Their rocket is called Zhuque 3
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or ZQ3, and it's a big one.
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Stainless steel construction, liquid methane
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propulsion, standing 76.6
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meters tall. For comparison, a Falcon 9
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is about 70 meters. This thing is taller
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than what SpaceX flies.
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Avery: So already an ambitious vehicle before you
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even get to the landing.
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Anna: Exactly. And landing is the part that matters
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here. Zoo K3 flew for the first time back in
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December 2025. That flight actually
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reached orbit successfully, which is already
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a big deal for a new rocket. But the landing
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attempt on the first stage didn't work out.
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Avery: So this was the do over.
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Anna: This was the do over. And yesterday, August
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19th, they nailed it. Liftoff was from the
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Dongfang Commercial Space Innovation Zone in
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northwestern China. And about eight minutes
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after launch, the first stage came down on
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four landing legs, roughly
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390km downrange, out
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in Minquin County, Gansu Province. It
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came in on a single Tiem Kwei 12 engine.
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Touched down close to dead center on the pad.
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Avery: Eight minutes from launch to landing. That's
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a very SpaceX shaped timeline.
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Anna: It's the same basic playbook. Yeah. Boost,
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separate, flip, come back down under power.
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Nobody outside SpaceX had made that work on
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an orbital class booster with actual
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repeatability. Until now. There have been a
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couple of smaller Chinese hop tests and
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suborbital attempts from other companies, but
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landing an orbital class booster on a real
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orbital mission is a different tier of
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difficulty.
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Avery: What does Landspace actually get from one
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successful landing? Is the booster flying
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again next week?
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Anna: Not next week, no. This is very much a prove
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the concept flight rather than a, uh, ready
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for daily reuse flight. But it's the step
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everything else depends on. Landspace
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themselves are, uh, framing it as moving
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toward the engineering application phase of
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reusability. In other words, this is where
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you stop asking can this work at all? And
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start asking how do we make this routine?
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Avery: Any hiccups? These things usually aren't
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perfectly clean.
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Anna: The core landing itself was clean, legs
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deployed, touched down where it was supposed
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to. Some reporting mentioned activity in the
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aft section of the booster after landing,
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which, given this is methane fueled hardware
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coming down hot isn't unheard of even on
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successful landings. SpaceX has had post
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landing fires on otherwise successful Falcon
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9 recoveries too. It doesn't take away from
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the fact that the vehicle landed intact and
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upright.
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Avery: So bottom line, why should our listeners care
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about one Chinese company landing one
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rocket?
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Anna: Because reusability is the thing that
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actually changes the economics of
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spaceflight. It's why Falcon 9 turned SpaceX
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from one very good rocket company into the
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company that now launches more than anyone
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else multiple times a week. China's had
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a state level reusable rocket effort in
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progress for years, but this is the first
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time a private Chinese company has shown it
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can do the hardest part. Landspace just put
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itself in what's genuinely a very short list
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of organizations on Earth that have landed an
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orbital class booster.
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Avery: A list that's about to get a
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Anna: little more competitive, which is good for
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everyone watching prices honestly.
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Next up, over to exoplanets and a
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planet that's breaking the rules just by
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existing.
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Avery: Go on.
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Anna: It's called GJ523B.
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Team led by Max Croft at the University of
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Wisconsin Madison, found it using NASA's
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TESS spacecraft, then confirmed it with
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follow up observations from the Wynn
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3.5-meter telescope at Kitt Peak in
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Arizona. Here's the number that makes it
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interesting. This planet is 23
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and a half times the mass of Earth.
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Avery: Okay, so a mini Neptune gas envelope
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and all.
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Anna: That's exactly what you'd expect. And that's
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exactly what it isn't. It's only about 2 1/2
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times Earth's width. Do that math. 23
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times the mass in barely 2 1/2 times the size
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and you get something extremely den and
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as far as they can tell, mostly rock. Not a
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puffed up gas world at all.
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Avery: Why is that a problem?
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Anna: Because planet formation models are pretty
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clear on this. Once a rocky core gets big
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enough and 23 earth masses is well past
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that threshold, it should have enough gravity
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to grab a thick hydrogen helium atmosphere
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from the disk of gas around its young star
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and balloon outward the way Neptune or Uranus
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did. DJ523B had
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every opportunity to do that. It orbits its
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star every 17.75 days
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and the whole system is only about 170
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million years old. Young enough that there
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should have still been plenty of gas around
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when it formed.
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Avery: And instead it just didn't bother.
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Anna: Instead it just stayed rock all the way up to
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23 earth masses. Croft's own quote on
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it was this isn't what we expected at all.
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Which for a planetary scientist is basically
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Avery: shouting, so what's the explanation?
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Anna: Honestly, right now they don't fully have
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one. Maybe it formed somewhere else closer
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in, in a gas poor environment and never had
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the chance to accrete an atmosphere. Maybe it
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did have one and something stripped it away
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early. That's the appeal of finding it. It's
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a genuine outlier that doesn't fit the
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models, which usually means there's a piece
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of planet formation physics we're still
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missing. I'll flag this result's been
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submitted to the Astronomical Journal, but
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hasn't gone through peer review yet. So
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consider it an exciting first look rather
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than a settled result.
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Avery: The universe's way of telling planetary
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scientists they're not done yet.
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Anna: It never is.
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Avery: Alright, this next one is genuinely one of my
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favorite kinds of stories. Extreme physics,
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extreme numbers.
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Anna: You're going to like this. Then there's a
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star newly cataloged as S301
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that's been found orbiting Sagittarius A,
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the supermassive black hole at the center of
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our own galaxy.
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Avery: We've talked about the S stars before, right?
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The ones that whip around Sagittarius A on
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tight orbits we have.
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Anna: And S301 just took the crown from all
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of them. It gets within 12 astronomical
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units of the black hole at closest approach.
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That's closer than any star ever tracked
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around. Sagittarius A, moving at, uh, roughly
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25,000 kilometers per second. And
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it completes one full orbit in just
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8.7 years.
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Avery: 8.7 years to loop around the
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supermassive black hole. For comparison,
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Jupiter takes about 12 years just to go
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around our sun, right?
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Anna: And Sagittarius a is about 4
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million times the mass of our Sun. So The
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Physics Environment S301 is living in
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is nothing like anything in our solar system.
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This was found by a team led by K. Abdel
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Diam at the Paris Observatory, working with
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Felix Meng and Stephan Gillison at the Max
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Planck Institute, Juana Sorno at Paris
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psl and the broader collaboration is directed
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by Reinhard Genzel, Nobel Laureate for his
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work proving Sagittarius A is a
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supermassive black hole in the first place.
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Avery: So why does one extreme star matter
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beyond just being a cool record breaker?
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Anna: Because an orbit this tight and this precise
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becomes a physics instrument. General
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relativity predicts that a, uh, spinning
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massive object drags spacetime around with
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it. It's called the lens theoring effect,
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or frame dragging. We've measured tiny
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versions of this effect around Earth with
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satellites. Nobody has ever directly
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measured it around a, uh, supermassive black
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hole because you need a star orbiting close
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enough, fast enough and predictably enough
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to detect the tiny relativistic wobble it
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causes.
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Avery: And S301 threads that needle.
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Anna: That's the hope. The team thinks that with
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continued observation, they could measure
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Sagittarius A's actual SP
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within a decade. That would be the first
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direct spin measurement of any supermassive
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black hole anywhere. Not modeled,
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not inferred from surrounding gas.
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Measured from watching a star get pushed
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around by the black hole, literally dragging
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space itself.
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Avery: A, uh, decade's a long wait, but that's a
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hell of a payoff.
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Anna: Worth the patience.
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Alright, moving on to our last story before
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we get to tonight's sky. And this one's a
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quiet result that could have a pretty loud
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effect on cosmology.
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Avery: How loud are we talking?
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Anna: Up to four times loud. A team led by
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Chloe Chang at Leiden University looked at
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nine quiescent galaxies, meaning galaxies
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that have basically stopped forming new
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stars. Sitting at a redshift of about
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0.7, they used James Webb's
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NIR SPECT instrument, combined with data from
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the Very Large Telescope's LEGA survey to
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look really closely at the actual population
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of star stars inside these galaxies
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and found something we'd been missing. A lot
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of something. Turns out these galaxies
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contain far more faint, low mass stars
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than anyone had accounted for. They'd simply
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been outshone and hidden by the smaller
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number of bright stars in the same galaxies.
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Once you properly count the dim ones, the
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true stellar mass of these galaxies goes up
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by something like a factor
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Avery: of four, four or times the mass.
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Just hiding in plain sight.
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Anna: Hiding in Plain sight. And it wasn't random.
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Which galaxies had the most hidden mass
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either. The oldest galaxy in the sample,
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one that started forming stars less than 500
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million years after the Big Bang, had the
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largest hidden population of low mass stars.
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Avery: Why would older galaxies hide more mass
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specifically?
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Anna: That's the open question, and it's a
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genuinely important one, because it means the
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ratio of small stars to big stars. What
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astronomers call the initial mass function
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might not be the same constant everywhere and
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everywhen, the way models have generally
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assumed. If early galaxies
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systematically formed proportionally more low
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mass stars, every mass estimate we've made
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for the early universe using the standard
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assumption could be off.
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Avery: Which affects a lot more than just these nine
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galaxies.
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Anna: Right. It touches how we calculate galaxy
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masses across basically all of early universe
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cosmology. And there's a nice side effect
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too. More low mass stars means more
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potential hosts for rocky Earth sized
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planets in the early universe. This was
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published in Nature Astronomy under the very
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on the nose title, Hidden Mass in Early
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Galaxies Revealed by bottom, Heavy initial
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Mass Functions.
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Avery: The early universe just got a lot more
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crowded and a lot heavier in one paper.
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Anna: Webb keeps doing that to cosmology this year.
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Avery: All right, let's get people outside tonight.
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What are we looking at?
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Anna: Grab a telescope if you've got one, because
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tonight's, uh, a genuinely good moon night.
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It's about 56% illuminated right now, and
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if you look right along the sunrise
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terminator, that line between lit and
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shadowed, you'll find the crater Theophilus
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down along Mare Nectaris.
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Avery: What makes that one worth hunting down?
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Anna: Specifically, with the sun that low on it,
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the shadows are dramatic. You get
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Theophilus, sharp, heavily terraced walls,
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seamless standing out in real relief. Plus a
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big multi pointed central peak casting its
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own shadow. It's one of those craters that
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actually looks three dimensional through a
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scope tonight instead of just a flat circle.
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Avery: And um, for anyone without a telescope
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Anna: handy, step outside right after sunset and
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look west. Venus is still an absolute
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beacon out there at, ah, magnitude minus 4.1,
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easily the brightest thing in the sky besides
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the Moon. And if you're an early riser,
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Saturn's moon parade that we mentioned last
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episode is still running in the south
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southeast before dawn. Titan, Rhea,
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Tethys, Dion, all still lined up
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thanks to those unusually narrow, nearly
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edge on rings.
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Avery: Good night to actually use the equipment
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instead of letting it collect dust.
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Anna: Always is.
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And that's it for Today's episode. Series
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five, episode 172 in the
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books.
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Avery: Quick recap. Plan space makes history.
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Landing Z3's booster, a mega
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Earth that refuses to follow the rules, a
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star that might let us finally measure a
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black hole spin. Um, and James Webb showing
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us the early universe was heavier than we
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thought all along.
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Anna: If you enjoyed the show, the best thing you
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can do is tell a friend. Leave us a rating
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wherever you listen, and follow us on the
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socials at astrodaily Pod for updates between
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episodes. And of course, check out our
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website at astronomydaily IO for further
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details on all of these stories.
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Avery: We'll be back tomorrow with more from across
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the universe.
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Anna: Until then, keep looking up Clear
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skies, everyone.
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Sam mhm.
