How an Ancient Rock Carrying Earth’s Oldest Known Crystals Ended Up on the Moon
A Moon rock picked up by the Apollo 14 astronauts in 1971 may contain the oldest known sample of Earth ever discovered, according to a study published this week in Earth and Planetary Science Letters.
At an estimated 4.1 billion years old, the sample is senior to the earliest known samples on Earth, which are dated to about four billion years.
The rim of Cone Crater, photographed by Apollo 14 crew. Image: NASA/Apollo 14Bellucci, Nemchin, and their colleagues at NASA's Center for Lunar Science and Exploration (CLSE) identified this small specimen as terrestrial by the presence of quartz, feldspar, and zircon.
These minerals are common on Earth but rare on the Moon, and the crystallization patterns suggest they were formed in an environment that matches Earth's temperatures and oxidation levels. There is an outside chance that the sample originated on the Moon, the team said, but it's far more likely that it hails from Earth.
Read More:Life On Earth Was Seeded by Massive Collision That Formed the Moon
According to David Kring, CLSE principal investigator and a senior author on the recently published journal article, the next step is to look for similar mineral signatures in lunar samples to find more relics of our young planet.
"It is an extraordinary find that helps paint a better picture of early Earth and the bombardment that modified our planet during the dawn of life," Kring said in a statement.
How mind-boggling that crystals formed on primordial Earth ended up making a cataclysmic voyage to the Moon, only to be eventually brought home by some random ape species that made the same trip four billion years later.
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