New study provides new clues about the formation of the moon.
The Moon is Earth’s closest celestial neighbor, but still we don’t know everything about it. In fact, we don’t even know exactly how the Earth got its moon.
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Now, researchers from UCLA have closely analyzed moon rocks brought back to the earth by Apollo missions and provided new clues about the formation of the moon. Researchers found that the moon was created by a violent, head-on collision between Earth and a forming planet called Theia around 100 million years after the Earth was formed.
Science already knows that around 4.5 billion years ago, a massive collision took place between Earth and another planet which resulted in the formation of Moon. The collision was thought more of a powerful side-swipe where Earth hit the side of Theia, at an angle of 45 degrees or more but new analysis points to a strong head-on collision.
The key here is the chemical signature in the rock’s oxygen atoms. Earth, Mars and other planetary bodies in our solar system all have their own distinctive ratio of oxygen such as almost 99.9% of Earth’s oxygen is 0-16 because each atom contains eight protons and eight neurons.
According to a previous report, Moon also has its own unique ratio of oxygen isotopes, which is different from the Earth. But latest research suggests that this is not the case. Oxygen in all moon rocks had a chemical signature similar to Earth’s oxygen, according to new research.
“We don’t see any difference between the Earth’s and the moon’s oxygen isotopes; they’re indistinguishable.” Edward Young, professor of geochemistry and cosmochemistry and lead author of the study said in statement.
Researchers used cutting-edge technology to carefully measure the oxygen isotopes of moon’s rocks and then verified it with UCLA’s new mass spectrometer.
The similar ratio of oxygen supports the case for a head-on collision rather than a side-swipe. If Earth and Theia would have been collided in a glancing side blow, the majority of moon should be made of Theia and it should have different oxygen isotopes from Earth. A head-on collision is likely the reason why moon and Earth’s oxygen isotopes are same.
“Theia was thoroughly mixed into both the Earth and the moon, and evenly dispersed between them,” said Young. “This explains why we don’t see a different signature of Theia in the moon versus the Earth.”
The “planetary embryo” called Theia could not bear the brunt of the collision and torn apart. The forming planet was thought to be about the size of Mars. If it had survived, it would have grown and probably became a planet.