How Was the Moon Formed?

The moon formed a hundred million years after the creation of the solar system. This has left scientists wondering what was the cause of our planet’s satellite to birth if it didn’t come from the events that formation of the planets. Here are just three of the most plausible explanations. 

Giant impact hypothesis

The prevailing theory supported by the scientific community, the giant impact hypothesis suggests that the moon formed when an object smashed into early Earth. Like the other planets, Earth formed from the leftover cloud of dust and gas orbiting the young sun. The early solar system was a violent place, and a number of bodies were created that never made it to full planetary status. One of these could have crashed into Earth not long after the young planet was created.

Known as Theia, the Mars-sized body collided with Earth, throwing vaporized chunks of the young planet’s crust into space. Gravity bound the ejected particles together, creating a moon that is the largest in the solar system in relation to its host planet. This sort of formation would explain why the moon is made up predominantly of lighter elements, making it less dense than Earth — the material that formed it came from the crust, while leaving the planet’s rocky core untouched. As the material drew together around what was left of Theia’s core, it would have centered near Earth’s ecliptic plane, the path the sun travels through the sky, which is where the moon orbits today.

According to NASA, “When the young Earth and this rogue body collided, the energy involved was 100 million times larger than the much later event believed to have wiped out the dinosaurs.”