The Apollo moon missions (11 through 17, minus the infamous 13) collected more than 800 pounds of moon rock. But whatever happened to those samples?
Astronomy contributor Jean Creighton says a few things. About 32 pounds have been used for science so far; another 30 pounds are being displayed at museums around the country. But most of the moon rock are being preserved in as pristine condition as possible at the Lunar Sample Lab at the Johnson Space Center in Houston.
"We're still learning from the lunar samples that we got 40 years ago," she says. "This rock today gives us new insights about how and when the moon formed, how planetary orbits evolved over time, and finally whether and how much water there is present, which of course is of great interest to us."
For example, Creighton says how abused the moon rocks look, and the craters they are found in, can tell us a lot about when and how badly the moon was hit by asteroids.
"We know 3.8 to 4.1 billion years ago there was a massive somewhat inexplicable heavy bombardment of the moon, so we can look at that and say, 'Wow, what on earth,' or 'What in the solar system could have caused this sudden release of many many objects?'" she says.
One theory behind the bombardment is that the giant gas planets, like Jupiter, moved in their orbits, causing "mayhem among asteroids." Creighton says there is evidence for this in other solar systems, where a large number of gas planets are located closer to their stars than Jupiter is to our sun.
"This idea is perhaps reinforced from our own solar system; maybe Jupiter and Saturn weren't always as stable," she says. "Perhaps they moved over time, and that is again, in sort of agreement with what we're seeing with other solar systems."
Creighton says our weathered moon rocks, with their signs of abuse, may be additional evidence of such planetary musical chairs.
In other moon news, a Lunar Reconnaissance Orbitor is currently in space, providing us with a complete map of the moon - including its far side.
Lake Effect astronomy contributor Dr. Jean Creighton is the Director of the Manfred Olson Planetarium, located on the campus of the University of Wisconsin-Milwaukee. She joins us each month to talk about the universe.