Scientists have discovered traces of another world in rock samples
from the moon — and it’s evidence of the planet that once crashed into
Earth to form our rocky satellite. It’s been believed since the ’80s
that the moon was created when a planet called Theia hit Earth 4.5
billion years ago. But until now there hasn’t been any evidence in lunar
samples to confirm the theory.
Now, a new analysis
of rock brought back to Earth by Apollo astronauts reveals subtle
differences in the composition of the material which makes up the moon
compared to that of our planet. The researchers measured the difference
in the isotopic composition of oxygen contained in rocks from Earth and
moon — that’s the ratio of oxygen atoms with subtly different atomic
weights.
They found a difference between the rock samples — which, the
researchers claim, confirms the theory that the moon was created by a
dramatic collision between Theia and Earth. Their results are published in Science.
However, the differences are smaller than the researchers expected.
Similar analysis of meteorites from Mars and the outer solar system
yield far larger disparities, so scientists are now scratching their
heads over why this new analysis provides results that are so similar.
Some have suggested Theia actually formed very close to Earth in the
early days of our Solar System; others reckon that the impacting planet
could have been bigger than we thought, which could have caused the
Earth to pick up many of the qualities of its incoming rock too.
Regardless, we’ve now found evidence that Theia did indeed hit the Earth
to form the moon.
[Source via BBC]
Saturday, June 07, 2014
We've Found Traces Of Another World On The Moon
6:39 AM
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