Earth and Moon came from same material: Scientists

Sharing a fresh view of how the Moon was formed, a team of scientists at University of Maryland has generated a new isotopic fingerprint -- the geological equivalent of a DNA "fingerprint" -- of the Moon suggesting that the Earth and its satellite were formed from the same foreign body.

Till date, planetary scientists believe that within the first 150 million years after our solar system was formed, a giant body roughly the size of Mars struck and merged with Earth, blasting a huge cloud of rock and debris into space.

This cloud eventually coalesced and formed the Moon, according to this theory.

"The problem is that Earth and the Moon are very similar with respect to their isotopic fingerprints, suggesting that they are both ultimately formed from the same material that gathered early in the solar system's history," explained Richard Walker, professor of geology and co-author of the study.

"This is surprising, because the Mars-sized body that created the Moon is expected to have been very different. So the conundrum is that Earth and the Moon should not be as similar as they are," he added.

By zeroing in on an isotope of Tungsten present in both the Moon and Earth, the team is the first to reconcile the accepted model of the Moon's formation with the unexpectedly similar isotopic fingerprints of both bodies.

The results suggest that the impact of Theia -- the isotopic "fingerprint" of the foreign body that Moon should carry -- into early Earth was so violent that the resulting debris cloud mixed thoroughly before settling down and forming the Moon.

This finding supports the idea that the mass of material created by the impact, which later formed the Moon, must have mixed together thoroughly before the Moon coalesced and cooled.

It also largely rules out the idea that the Mars-sized body was of similar composition, or that the Moon formed from material contained in the pre-impact Earth.

"This result brings us one step closer to understanding the close familial relationship between Earth and the Moon. We still need to work out the details, but it is clear that our early solar system was a very violent place," the authors concluded.

The findings appeared in the journal Nature.