July 20, 2009

Lunar rocks suggest history of Earth

Lunar rocks taken during the Apollo space missions suggest our moon was part of the Earth 4.5 billion years ago, scientists said.

The rocks obtained four decades ago suggest a smaller planet hit Earth, creating the moon and enlarging the Earth, said Gary Lofgren, a NASA geologist who showed the Apollo astronauts how to spot interesting rocks.

The composition of the rocks also suggest the Earth and moon were slammed by violent storms of space debris, possibly triggered by a reshuffling of the solar system, Lofgren told The Philadelphia Inquirer.

During the Apollo program astronauts collected 842 pounds of rock and soil, several hundred pieces of which are still sent annually to scientists studying their formation, said Lofgren, now NASA's curator of lunar samples.

The lunar rocks may be the best hope of understanding the first half-billion years of Earth's history, said David Kring, a researcher at the Lunar and Planetary Institute in Houston.