This artistic image represents the collision that could have formed the Moon 4,530 million years ago. There are several theories about the formation of the Moon. Today, the most accepted is the big impact theory. Bill Hartmann formulated it in the 70s, when he found that the composition of the lunar rocks was similar to that of the Earth.
It is believed that the Earth collided with a twin planet the size of Mars, called Tea (by the Greek goddess Theia). Part of its mass merged with that of the Earth, increasing its size and gravity. The rest of the fragments were dismissed and the Earth's gravity captured them. They formed a ring of asteroids orbiting around our planet. Over time, they grouped and condensed to form the Moon.
The most recent studies of the lunar rocks indicate that it solidified between 50 and 150 million years after the origin of the Solar System. According to this, the Moon formed much later than it had always been believed. At first, the Moon was much closer to Earth. Today continues to move away, at a rate of more than 3 cm per year.
The formation of the Moon and its orbit stabilized the axis of rotation of the Earth at 23.5º. This is how our climate was regulated. It is the cause of four seasons. It also slowed the rotation speed, making the days longer. Without the Moon, the entire evolution of the Earth would have been different.
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