The dangers of space junk are becoming clearer.

Why it matters: Space debris threatens satellites and astronauts and is cluttering parts of Earth's orbit that are in high demand.

• As junk is created — either through satellites that run out of fuel, collisions between spacecraft or other events — it can stay in orbit speeding around Earth at more than 17,000 mph for months or years, putting other spacecraft at risk.
• Earlier this year, a report filed by SpaceX to the FCC showed that the company's Starlink satellites had to maneuver to avoid collisions 25,000 times between December 2022 and May 2023, reflecting an increasingly crowded space environment.

What's happening: Scientists and satellite operators have long understood that junk whizzing around in orbit puts operational satellites at risk, but now, the risks to Earth itself are starting to take shape.

• An FAA report earlier this month suggested surviving debris from constellations of satellites and rocket parts burning up in the atmosphere could kill or injure someone on Earth every two years by 2035. (SpaceX, however, has disputed this claim, saying it was based on an analysis of old data.)
• According to a new study in the Proceedings of the National Academy of Sciences, traces of metals from satellites burning up as they fall back to Earth are polluting the planet's atmosphere, though it's not yet clear what effect those pollutants are having on our planet.
• "We are finding this human-made material in what we consider a pristine area of the atmosphere," study co-author Dan Cziczo, of Purdue University, said in a statement. "And if something is changing in the stratosphere — this stable region of the atmosphere — that deserves a closer look."

Between the lines: While space junk has been a serious topic of conversation for scientists and people in the space industry for years, policy has taken some time to catch up.

• "The question is: How do you update the governance to really reflect the space environment as it currently exists?" the Secure World Foundation's Victoria Samson tells Axios.
• Space junk "was always a theoretical concern, and now we're faced with the actuality," Samson says. "Unfortunately, policy oftentimes is beaten by technology, which doesn't always lead to good policy as it tries to play catch up."

Meanwhile, there are signs that policymakers are starting to take the space junk problem seriously.

• The FAA recently proposed a rule that would require operators to dispose of the upper stages of rocket bodies in specific ways in a set amount of time in an effort to limit debris creation.
• The FCC also recently issued its first-ever fine to the satellite TV provider Dish for its failure to safely de-orbit a satellite.

The intrigue: Companies are starting to look for possible ways to make money while solving these issues.

• LeoLabs and others are focusing on tracking satellites and debris, helping alert government and commercial actors to close calls.
• Privateer is working on finding new and better ways to track how junk moves in space, giving scientists and operators a better sense of what's happening in orbit at any given time.
• Other companies, like Northrop Grumman's SpaceLogistics, are focusing on satellite servicing to extend the lives of aging spacecraft in orbit.

Yes, but: The business case for cleaning up space junk is still murky.

• "Who pays for the cleanup? That's always been the dirty little secret of debris removal ... that there's just no business case for that in low Earth orbit," Samson says.

A new analysis of lunar rocks collected during the Apollo program suggests our Moon is 40 million years older than originally expected.

Why it matters: Understanding our Moon is crucial to our understanding of our solar system as a whole.

• "The Moon is an important partner in our planetary system. It stabilizes the Earth's rotational axis," Philipp Heck, of the Field Museum, and one of the authors of a study in the journal Geochemical Perspectives Letters detailing the new finding, said in a statement.
• "It's the reason there are 24 hours in a day. It's the reason we have tides. Without the Moon, life on Earth would look different."

What they found: Researchers using an advanced analytics technique found the oldest zircon crystals in lunar samples delivered to Earth in 1972 are 4.46 billion years old — 40 million years older than previous estimates.

• The team counted how many atoms in the zircon crystals have gone through radioactive decay.
• Atoms undergoing radioactive decay transform from one type of element into another on a known timescale, allowing scientists to piece together an accurate estimate of a sample's age.
• "In an hourglass, sand flows from one glass bulb to another, with the passage of time indicated by the accumulation of sand in the lower bulb," Heck said. "Radiometric dating works similarly by counting the number of parent atoms and the number of daughter atoms they have transformed to. The passage of time can then be calculated because the transformation rate is known."

Background: Scientists think the Moon formed when a huge impact early in Earth's history flung material from the newly forming planet out into space.

• That debris eventually coalesced and created our Moon.
• "When the surface was molten like that, zircon crystals couldn't form and survive," Heck added. "So, any crystals on the Moon's surface must have formed after this lunar magma ocean cooled. Otherwise, they would have been melted and their chemical signatures would be erased."

🪨 1 fun thing: NASA has stored Moon rock samples from Apollo for decades. Scientists can request access to those lunar samples from the space agency in order to study them in new ways.

💸 NASA starts reassessment of Mars Sample Return architecture (Jeff Foust, SpaceNews)

🚀 You won't hear much about the next chapter of space travel (Marina Koren, The Atlantic)

🛰 NASA wants the Voyagers to age gracefully, so it's time for a software patch (Stephen Clark, Ars Technica)

☄️ NASA's OSIRIS-REx mission officially surpasses asteroid sample size goal (Monisha Ravisetti, Space.com)

Solar eclipses — in all their forms — can feel like somewhat spooky events.

• It's always strange to see the Sun with a chunk taken out of it, even temporarily.
• NASA astronaut Jasmin Moghbeli captured this photo of the annular solar eclipse on Oct. 14 from the International Space Station as millions of people on Earth were treated to a similar view from the planet's surface.