Apollo astronaut and geologist Harrison "Jack" Schmitt doesn't buy the prevailing theory that the moon formed from pieces of Earth that were shot into space after a giant impact.
Instead, Schmitt suspects Earth's gravity captured a smaller body that had built itself up in a nearby orbit.
Additional evidence may be found inside a deep crater on the moon's south pole, one of several areas Schmitt, now a professor at the University of Wisconsin, advocates exploring, not only for science, but to prepare for human missions to Mars.
As a follow-on program to the International Space Station, the moon fell out of favor as a destination for the U.S. human space program due to high costs. Instead, the Obama administration wants NASA to plan for a manned mission to an asteroid by 2025, an interim milestone toward an eventual human expedition to Mars.
Schmitt, a member of the last Apollo crew that blasted off 40 years ago on Dec. 7, 1972, believes that's a mistake.
"I think an asteroid is a diversion," Schmitt told Discovery News. "If the ultimate goal is to get to Mars, you have a satellite only three days away that has a great deal of science as well as resources."
"The science of the moon has just been scratched," Schmitt added. "We've hardly explored the moon."
For example, new studies of the rock and soil samples retrieved during the six Apollo expeditions to the moon have raised questions about how Earth's companion formed.
The prevailing theory has been that a Mars-sized object bashed into Earth during the solar system's early days, causing debris to shoot into space ( via news.discovery.com ).