This Week in Space 186: "Snow on the Moon?"

Date: November 14, 2025
Hosts: Rod Pyle (Ad Astra Magazine), Tarek Malik (Space.com)
Guest: Dr. Jim Green (Former NASA Chief Scientist, Metavisionaries Founder)

Overview

This episode dives into lunar science and history with former NASA Chief Scientist Dr. Jim Green, exploring the origins, evolution, and unexpected climate of the Moon—including the fascinating possibilities of "snow" in its ancient past. The hosts also break down major space news headlines: Chinese spacecraft drama, Blue Origin's New Glenn milestones, the latest cometary intrigue, Artemis program delays, and how all this connects to the Moon’s role in Earth's habitability and space exploration's future.

Key News & Discussion Segments

1. Chinese Spacecraft Switcheroo (03:54–08:43)

• The crew of Shenzhou 20, initially stranded due to spacecraft damage (cracked descent module window likely from space debris), returned to Earth aboard Shenzhou 21’s capsule, leaving the Shenzhou 21 crew without a reliable emergency ride home.
• Rod and Tarek discuss technical and logistics challenges, debris threats, international docking capabilities, and potential future rescue scenarios.

Quote:
"It's not just any problems because they had, quote, unquote, damage that they suspected was from space debris... cracks in the window, there are tiny cracks in the portal window, the forward portal window of the Shenzhou capsule."
—Tarek Malik (05:11)

2. Blue Origin's New Glenn Milestone (08:43–13:09)

• New Glenn successfully launched two NASA Escapade Mars probes and landed its booster on a barge, marking the first private interplanetary mission with full booster recovery on its maiden attempt at sea.
• Comparison to SpaceX’s evolution; discussion of industry implications for reusable rockets.

Quote:
"Blue Origin went straight to the ocean... this means that SpaceX is not the only game in town anymore when it comes to vertical landings... Blue Origin now has their foot in that door."
—Tarek Malik (12:08)

3. Comet Atlas Disintegrates (13:09–14:06)

• Newly discovered Comet C/2025 K1 (Atlas) broke into three pieces after a solar flyby.
• Distinction drawn between this and interstellar objects (e.g., speculation referencing Avi Loeb).

Artemis Program Delay & Politics Discussion (14:14–18:29)

• Internal SpaceX documents reportedly confirm Artemis' lunar landing has slipped to 2028, causing concern over schedule viability and political pressures for a lunar landing before the end of the current US administration’s term.
• Eric Berger piece on alternate Starship/Dragon lunar mission architectures referenced.

Notable Exchange:
Tarek: "The reason... there's a lot of push to land people on the moon by 2028 is because that's during the current administration." (15:09)
Rod: “Nixon had to have his moment... I remember even as a kid... get off the phone and let them go collect rocks.” (16:26)

4. Lunar Formation and Early Evolution (23:00–31:40)

Dr. Jim Green joins for an in-depth exploration:

• Early lunar formation hypotheses: The Moon is unusually large compared to Earth; sample analysis from Apollo missions revealed Earth-Moon compositional similarities, leading to adoption of the Giant Impact Hypothesis (collision with protoplanet Theia).
• The Moon began very close to Earth, appearing huge in the sky, but is slowly moving away (currently ~60 Earth radii, still receding).
• The Moon's presence stabilizes Earth's tilt, limiting climate swings—crucial to habitability.
• Loss of Moon would mean long days, wild seasons: “The Moon has made the Earth uncommonly habitable.” (29:01)

Memorable Moment:
Tarek links the Moon’s stabilizing role to “Game of Thrones”’ endless seasons, theorizing lunar absence would create climate chaos (31:40).

The Moon’s Ancient Magnetosphere and Shared Atmosphere (37:52–43:30)

• Lunar rocks show remnants of a past magnetic field; recent work confirms the Moon once had a functional magnetosphere.
• For hundreds of millions of years, the Moon’s magnetosphere was inside Earth’s; magnetically channeled material, including nitrogen, from Earth's early atmosphere reached the Moon.
• Evidence: Greater-than-expected nitrogen found in lunar regolith.
• Crucial insight: moon’s proximity and magnetic connectivity enabled transfer of volatile elements.

Quote:
"Material from the Earth will run down that magnetic field and precipitate into the lunar environment... Well, it's coming from the Earth. And it came probably during the time the Moon had a magnetosphere."
—Dr. Jim Green (42:40)

Volcanic Activity & Lunar "Weather": Snow on the Moon? (46:02–54:54)

• Massive impacts during the Late Heavy Bombardment era led to widespread lunar volcanism—magma upwelling released “volatiles” (water, CO₂, sulfur compounds, etc.)
• A mix of volcanism and magnetic shielding allowed a temporary lunar atmosphere: up to ~12 millibars (twice Mars’ atmosphere).
• Ancient lunar atmosphere and outgassing: water vapor and other volatiles moved to polar cold traps, where they condensed/froze–literally “snowing” at the lunar poles.

The Big Payoff:
Rod: "Can you kind of give us an idea of what a day might have been like on the Moon billions of years ago?" (71:11)
Jim Green:
"So this is a perfect area... that material is going to migrate to that polar area and then probably snow out... So you're going to see carbon dioxide snow, you're going to see H2O snow... And that's what we see on Pluto... that's got to happen on the... Moon at one time. We believe that happened right after the late Heavy Bombardment and the growth of that atmosphere." (73:10)

Science vs. Industry: The Race for Lunar Resources (49:58–54:59)

• Water and other volatiles in lunar polar ice represent a scientific treasure trove—unique, unrecoverable record of Earth-Moon atmospheric evolution, not just a mining target.
• Urgency expressed in getting cores and analysis before commercial extraction disrupts these invaluable data layers.
• Micrometeoritic “gardening” may mix up some stratigraphy, but less so at the poles.

Is There Life Hidden in Lunar Ice? (53:54–54:59)

• Though the Moon had water, raw materials, and energy, it didn’t remain habitable long enough for life to arise: “If there is [life], we're going to be bringing it. ...The Moon just didn't have the time with the environment that it had.” —Dr. Jim Green (54:11)

VIPER Lunar Rover, Magnetic Die-Off, and Mining the Moon (58:12–66:18)

• NASA’s VIPER rover is back on track for lunar south pole exploration, equipped to drill for buried volatiles and help answer questions about mixing, ice content, and past magnetic protection.
• Moon’s magnetic field died out after ~500 million years, but its signature remains in ancient rocks.
• Beyond water: platinum group metals (iridium, palladium, etc.) from asteroid impacts are on the Moon—potential future mining targets as Earth’s terrestrial resources dwindle.

Pristine Lunar Samples & What’s Next (66:24–71:04)

• Apollo 17’s recently unsealed “core” sample demonstrates why saving material for future, more advanced lab analysis matters—evolving technology is unlocking new secrets.
• Dr. Green champions Mars Sample Return as the next step for planetary science.

Quote:
"You have to realize going into this, we knew the technology was going to do nothing but improve... so half the samples that came back from the Moon were stored, didn't touch them... now we have the opportunity to bring them out and really look at them."
—Dr. Jim Green (67:09)

Fun & Educational: Naming the Moon, and Metavisionaries (74:24–80:27)

• Should we call the Moon “Luna”? Why (and when) to capitalize "Moon" debated—NASA style guide weighs in.
• Dr. Green previews Metavisionaries: teaching space science in VR, global classroom domes, immersive learning.
  "All a student needs... is a code and their 3D system, and they can walk into a classroom, be totally awed, and talk to the former NASA chief scientist. Now, where in the heck can you do that?" (79:29)

Notable Quotes/Moments

• On Snow on the Moon:
  "So you're going to see carbon dioxide snow, you're going to see H2O snow... these volatiles are going to accumulate in and drop out." (Dr. Jim Green, 73:10)
• On Chinese Space Vehicles:
  "The Shenzhou is better in every way than the Soyuz." (Rod Pyle, 06:55)
• On why the Moon matters:
  "The Moon has made the Earth uncommonly habitable." (Dr. Jim Green, 29:01)
• On lunar mining:
  "If you're going to go find material, I'd go to the Moon... with the iron comes platinum group metals... we may have to, you know, mine them on the Moon." (Dr. Jim Green, 64:03)

Timeline of Major Segments

• Shenzhou/Chinese Space News: 03:54–08:43
• Blue Origin New Glenn: 08:43–13:09
• Comet News: 13:09–14:06
• Artemis/Political Pressure: 14:14–18:29
• Lunar Formation/Impact History: 23:00–31:40
• Moon’s Magnetosphere/Nitrogen Transfer: 37:52–43:30
• Volcanism & Lunar Atmosphere/Early “Snow”: 46:02–54:54, 71:11–74:00
• Resource Priority/Mining vs. Science: 49:58–54:59, 64:03–66:18
• Lunar Samples/VIPER: 58:12–71:04
• Naming the Moon & MetaVisionaries: 74:24–80:27

Closing

This sprawling, science-rich episode combines breaking news, deep-space history, planetary science, and quirky space linguistics with an entertaining, conversational vibe. Dr. Jim Green’s insights on lunar evolution, volatiles, and what we might discover in the Moon’s icy craters frame lunar exploration as both a scientific and human adventure. The future of Moon science and mining, the lingering mysteries in sample caches, and VR classrooms all point to a new era of discovery.

For more:

• TWiT.tv/ThisWeekInSpace
• Dr. Jim Green: Metavisionaries.io (when online)
• Tarek Malik: [Space.com], @tarikjmalik
• Rod Pyle: [astermagazine.com], [pilebooks.com]