Have you ever looked up at the moon and wondered from whence that magnificent orb came? A new study has added momentum to the theory that the moon is made of debris leftover from a collision between a young planet Earth and a rock the size of Mars — which were then both covered in meteorites. According to the Giant Impact Theory, this collision created the cosmic nightlight we know and love today.
According to Space.com, the dominant theory of the moon’s formation is called the Giant Impact Hypothesis, which was proposed in the 1970s. That theory suggests the moon was formed via a collision between two protoplanets, a young planet earth and another object roughly the size of Mars known as Theia.
According to the Giant Impact Theory, more than 60 percent of the moon should be made up of rock from Theia, but studies have shown its composition is nearly identical to that of Earth. This contradiction received some further explanation through a recent study out of the University of Israel, Haifa.
“As far as composition, the Earth and moon are practically twins, their compositions varying by at most a couple parts in a million,” said Allesandra Mastrobuono-Battisi, an astrophysicist and lead author of the study. “This contradiction has cast a long shadow on the giant impact model.”
The recent study shed new light on the issue by simulating collisions in the early solar system between 85 to 90 protoplanets, each of which had up to 10 percent of the Earth’s mass, along with 1,000 to 2,000 smaller bodies.
What did they learn? Space.com explains:
“The scientists found that within 100 million to 200 million years after the models began, each simulation typically produced three to four rocky planets, with the largest comparable to Earth’s mass. These worlds often were composed of material that was distinct from one another. However, they also found that 20 to 40 percent of the time, the composition of one planet was very similar to the makeup of the last protoplanet that had collided with it. This likelihood is about 10 times higher than previous estimates.”