What formed the holes on the moon?

Moons can occur around planet in a few different ways. They include:

- A major hypothesis is that a huge rocky mass the size of Mars collided with Earth about 20 million years after Earth formed. Material blasted out from Earth.

-The moon was formed elsewhere and captured by the gravity of the planet. This is what happens when an asteroid goes near enough to a planet, but does not collide with it, so it begins orbiting it.

-The moon and planet formed at the same time within each other's proximity from the same planetary material. This is called co-accretion.

-If an object collides with a planet the debris released into space can coalesce through gravity, to form a moon. This is how we think the Earth's moon was formed.

-The moon could have been once part of the planet. The planet's centrifugal force can cause a blob of magma to separate and harden to form a moon. For this to happen the planet must have been molten first.