A chunk of material brought back from the lunar surface by Apollo astronauts in 1971 harbors a tiny piece of Earth, a new study suggests. But given that the Earth was subjected to impacts during the Hadean eon, when the planet was forming 4.6 billion years ago, bits of Earth on the moon don't seem surprising to Kring and his team.
Apollo 14 commander Alan Shepard stands by the Modular Equipment Transporter (MET), a cart for carrying tools, cameras and sample cases on the lunar surface.
They found lunar sample 14321, also known as Big Bertha, is embedded with a rock fragment made of quartz, feldspar, and zircon. Chemical analysis of the rock fragment shows it crystallized in a terrestrial-like oxidized system, at terrestrial temperatures, rather than in the reducing and higher temperature conditions characteristic of the Moon. The rock was able to make this serendipitous collision with the moon because it was three times closer to Earth at the time.
This theory is the easiest explanation since the formation of such a fragment would need an oxidizing environment.
But if the rock formed so far beneath the Earth's surface, how was it jettisoned? He holds a B.A.in Psychology from the University of Toronto, and a Master of Science in Public Health (M.S.P.H.) from the School of Public Health, Department of Health Administration, at the University of North Carolina at Chapel Hill.
"It is possible that some of these unusual conditions could have occurred very locally and very briefly on the moon and the sample is a result of this brief deviation from normality", Nemchin said.
The fragment of Earth was blasted off the planet during a powerful impact some 4 billion years ago, researchers said.
A lot of the rocks we have on Earth aare pretty old, but none of them were around when our planet was first formed.
David Kring, CLSE principal investigator and a senior author of the recently published journal article, said that the next step is to look for similar mineral signatures in lunar samples to find more relics from the younger Earth. Impacts of this magnitude were capable of pulling out materials from deep within the Earth's surface.
We're not talking about a "Moon was once part of Earth" rock (that's just one hypothesis for the Moon's origin, anyway).
According to the release, "Previous work by the team showed that impacting asteroids at that time were producing craters thousands of kilometers in diameter on Earth, sufficiently large to bring material from those depths to the surface".
Around 26 million years ago, an asteroid hit the moon and created the Cone Crater. Researchers believe that the rock fragment may have originated on the Earth.
The rock is presumed to be the oldest known rock, formed around the same time our planet was formed, according to an analysis in Earth and Planetary Science Letters.
One of Earth's oldest rocks may have been dug up on the moon.
If we ever go back to the moon again, we might find more Earth samples lying around the surface.