As Earth’s closest neighbor in space, we know a lot about the moon. We know that the Moon is less than a third of the size of Earth. We know that every 27 days, the Moon rotates around Earth and spins at the same time. This means that the same portion of the Moon is always facing Earth, and the side that isn’t is often referred to as the Dark Side of the Moon.
All of this being said, there’s still a bunch of things that we’re learning about the Moon, and in fact, researchers are unraveling more mysteries nearly every day.
The Secrets of Our Lunar History
The Moon, says Bruce Betts, chief scientist of the Planetary Society, is a great tool for understanding our lunar history. For example, studying the South Pole-Aitken Basin, the oldest and largest crater on the Moon, tells us a history of long ago that’s largely been wiped out here on Earth because of water and erosion.
We can learn the impact history of the Moon, which tells us a lot about a time called the Late Heavy Bombardment, a period of continuous asteroid bombardment that helped shape what the solar system would become four billion years ago. Although, in recent years, this theory has been called into question, according to NASA. We can look at craters that would long have eroded from Earth to “nail down the chronological history of the Earth,” says Betts.
According to Matthew Murphy, a Ph.D. candidate with the Steward Observatory at the University of Arizona, we think that the Moon formed after an impact that the Earth had with a protoplanet early on in the life of the solar system.
“Such an intense and energetic collision is mind-boggling, and it's cool that we have a direct result of that collision just ‘floating’ around in the sky,” says Murphy.
Read More: The Moon Is Even Older Than Scientists Thought
The Moon and Its Water and Ice
In the past two decades, researchers have also gotten a better idea of where and how much water and ice can be found on the Moon. Without weather, craters full of water and ice largely stay put so they can be studied.
The next question in studying water and ice on the Moon, says Murphy, is how much water there is, where it is, and where it comes from. In 2020, the SOFIA mission first highlighted the presence of water in a crater on the Moon. This mission included a Boeing 747 carrying a giant telescope that flew at 38,000 feet to 45,000 feet, allowing astronauts to see the solar system in ways that they hadn’t before.
“This was a big surprise because we previously expected lunar water to only exist in really cold, permanently shadowed regions near the poles, and that regions receiving sunlight would have had any water long-since evaporated away,” says Murphy. “This is a big deal for potential habitability.”
The Moon is so interesting to us, says Murphy, because it’s the only planet other than Earth that we can see up close and personal. Even the planets that are closest to us, like Mars and Venus, appear as specks in the sky, but the Moon is different. And even though we’ve learned so much, there’s still so much left to know.
“I can look up at the Moon, trace out its craters with my own eyes, see its various colors, and just see that it's a real place that I could walk on the same way I'm walking on the Earth,” says Murphy. “For me, that really fires up a deep, child-like sense of excitement and wonder.”
Read More: Here Are 4 Reasons Why We Are Still Going to the Moon
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Chief scientist of the Planetary Society. Bruce Betts
Ph.D. candidate with the Steward Observatory at the University of Arizona. Matthew Murphy
NASA. SOFIA
Sara Novak is a science journalist based in South Carolina. In addition to writing for Discover, her work appears in Scientific American, Popular Science, New Scientist, Sierra Magazine, Astronomy Magazine, and many more. She graduated with a bachelor’s degree in Journalism from the Grady School of Journalism at the University of Georgia. She's also a candidate for a master’s degree in science writing from Johns Hopkins University, (expected graduation 2023).
