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What we don't know about the Moon

The surface of the Moon seen from above.
The Moon's surface from above. Photo: NASA/JPL-Caltech

The Moon is one of the most deeply studied objects in our solar system, and yet there is a lot we don't know about our nearest neighbor.

Why it matters: Most of our lunar knowledge comes from the samples brought home during the Apollo era and robotic spacecraft sent to the Moon. Future missions could help researchers piece together the solar system's early history and even give us an idea of what Earth was like right around the time life developed.

"I hope people think of the Moon not as just this remote object in space," NASA scientist Noah Petro told Axios. "But it's really an intimate part of the Earth."

Where it stands: Scientists think that around 4 billion years ago a major event in the history of the solar system known as the Late Heavy Bombardment took place. During this period, huge amounts of debris from the outer solar system smacked into the inner planets when the outer planets migrated in orbit.

  • While there's still some debate about whether that event occurred, scientists think that if it did happen, it was going on right around the time that life started to pop up on the early Earth.
  • Huge impacts on Earth at that time could have vaporized the oceans and sterilized the planet's crust, Johns Hopkins planetary scientist Brett Denevi told Axios.
  • Understanding what exactly went on during those chaotic days in the early solar system is key to figuring out how life may have evolved on Earth and when.

Scientists think there are likely meteorites from the Earth on the Moon that were sent there around that time as well.

  • Because the Moon acts as something of a time capsule, those rocks are probably preserved and could be found by future missions to the lunar surface.

The big picture: Understanding the Moon isn't just important for our understanding of Earth, but for the rest of the solar system as well.

  • Future Moon rock samples could help trace the position of our solar system in the Milky Way through the course of the millennia by looking at the signatures left behind in Moon dirt.
  • "As the Sun has been going around the galaxy, we'll have been passing in and out of dense interstellar clouds and close passes to exploding stars, all of these potentially recording in the lunar soils," Ian Crawford of Birkbeck, University of London told Axios.

What's next: As NASA plans to send humans back to the Moon by 2024, scientists hope their research interests will also come along as well, even if the main focus of the Artemis program is pure exploration.

  • Something as simple as getting more lunar rocks back on Earth from different areas on the Moon will help scientists learn more about the history and evolution of the world.
  • Human eyes are also more adept at picking out odd looking rocks or strange formations than the mechanical eyes of a rover or orbiter, so having people on the surface of the Moon would be a boon for research as well as exploration.

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