Earth Science

Earth History

Formation of the Moon

Study Tip
Similar to the formation of the Solar System, the formation of the moon is hypothesized to be a result of collisions.

The Moon

  • The Moon is Earth’s only natural satellite. Its orbit is 384,400 kilometers away from the Earth.
  • It is the brightest object in the sky after the Sun.
  • Scientists do not currently know the exact formation date of the moon, but estimate it to be around 4.5 billion years ago.
Study Tip
Similar to the formation of the Solar System, the formation of the moon is hypothesized to be a result of collisions.

Giant Impact Theory

  • The most widely accepted hypothesis for the formation of the moon is the giant impact hypothesis.
  • The giant impact hypothesis believes that the moon was formed as a result of a collision between the Earth and a large astronomical body the size of Mars.
  • When the asteroid struck the Earth, the energy from the collision melted the bodies. Heavier, denser materials stayed on Earth, while the lighter materials flew into space and began to orbit Earth. Eventually, this debris that was orbiting earth collapsed down and formed the Moon.
Moon
Concept Check
  • What is the Giant Impact Theory? Describe in detail what the theory states.