Free Republic

A chunk of Earth that could be 4.1 billion years old and is described as the planet's "oldest rock," may have been found and dug up on the Moon by Apollo astronauts, according to a new study. The possible relic was discovered and dug up in 1971 and scientists believe that it was sent off Earth, thanks to a powerful impact, possibly an asteroid or a comet. After colliding with the Moon (which at the time was three times closer to the Earth than it is now), it mixed with other lunar surface materials. "It is an extraordinary find that helps paint...

Explanation: Was the oldest known rock on Earth found on the Moon? Quite possibly. The story opens with the Apollo 14 lunar mission. Lunar sample 14321, a large rock found in Cone crater by astronaut Alan Shepard, when analyzed back on Earth, was found to have a fragment that was a much better match to Earth rocks than other Moon rocks. Even more surprising, that rock section has recently been dated back 4 billion years, making it older, to within measurement uncertainty, than any rock ever found on Earth. A leading hypothesis now holds that an ancient comet or asteroid...