Space

Another World Crashed into the Earth Billions of Years Ago to Form the Moon

Thomas Carannante
First Posted: Jun 06, 2014 07:03 AM EDT

Researchers are still analyzing lunar material that the Apollo astronauts brought back decades ago. A piece of lunar rock has led researchers to discover that the moon was caused by a collision between Earth and a foreign planet.

The German scientists that studied moon rocks gathered by the Apollo 11, 12, and 16 missions had their study published in the journal Science on Thursday. Through analyzing these moon rocks, they determined that the oxygen atoms found in the moon rocks have a different makeup than ones found on Earth.

The study is a confirmation of the widely accepted theory that the formation of the moon was a result of Earth colliding with the planet "Theia" over 4.5 billion years ago. The theory has been accepted since the 1980s, but this most recent study provides the most telling evidence.

"It was getting to the stage where some people were suggesting that the collision had not taken place," said Dr. Daniel Herwartz, the study's lead researcher, in this BBC News article. "But we have now discovered small differences between the Earth and the Moon. This confirms the giant impact hypothesis."

The "Giant Impact Hypothesis" proposed that the moon was created out of the debris left over from a collision between a young Earth and a Mars-sized body, known as Theia, but for years there has remained several unanswered issues put forth by this hypothesis. One of the unanswered issues dealt with lunar samples and their expected ratios of certain elements and compounds.

The isotopic composition of the lunar rocks was compared with those of Earth rocks, and the researchers found that the moon rocks possessed a 12 parts per million heavier kind of oxygen atom compared to that of Earth rocks. This is believed to provide evidence that Theia did indeed collide with Earth.

The whole argument was that if the moon and Earth rocks, after years of extensive studies, revealed any differences in isotopic composition (the ratio of different forms of oxygen), then it was likely that the Earth collided with Theia 4.5 billion years ago. Even with the miniscule difference they found, it's still strong evidence in support of the Giant Impact Hypothesis.

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TagsEarth, Moon

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