The moon has always fascinated humankind, ancient people thought of it as a goddess of both beauty and wrath, medieval times associated it with supernatural events and now scientists are trying to establish the origin and roles of our natural satellite. And it seems that apart from affecting the tides and the amounts of rainfall, the moon is proof of Earth’s collision with another planet.
Scientists have long tried to explain the presence of our lonely natural satellite that orbits our planet so closely. There have been various theories on how it came to be there, some dictated that the moon was attracted by Earth’s gravity, some that it is the remainder of the ancient protoplanet Theia.
The mystery was solved by a group of UCLA researchers that published an article in the Science journal this week that concludes that the moon is proof of Earth’s collision with another planet.
At birth, the solar system looked quite different from what we see today. Between Earth and Mars existed another planet, a smaller one, a protoplanet named Theia. And after approximately 100 million years of co-existence something made the two celestial bodies to come in contact.
The impact was not full-on, for that would have made both planets transform into space dust and debris, but rather a glancing blow that merged the two together, forming the Earth we know now, and the biggest chunk of debris left from the explosion was shaped into what we know perceive as being the moon.
In order to reach these conclusions, the UCLA researchers studied numerous lunar rock samples that were brought back by the Apollo missions and volcanic rock samples that have in their componence material that originates from the Earth’s mantle.
The researchers compared the levels of oxygen isotopes in both rock samples and they discovered that they were identical. The oxygen than can be found on Earth in a 99.99 percent concentration is O-16, which means that the oxygen molecule has an equal amount of protons and neutrons. But there are also traces of O-17 and O-18, an oxygen molecule with one, and respectively two, extra protons.
The concentration of these isotopes differs on every planet in the solar system, it’s a sort of planet fingerprint, which is why, upon discovering the fact that the moon and the Earth share the exact same levels, the researchers concluded that the moon was once part of the Earth.
The Earth-Theia collision also explains why the Earth has such a dense core for such a small planet. Of course, the impact should have been very energetic for the two planets to melt into each other in such a manner.
Even though further research must be undertaken, the UCLA researchers are convinced that the moon is proof of Earth’s collision with another planet.
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