In the Beginning: Formation of the Solar System

4.5 billion years ago

	The Milky Way galaxy

This big squeeze created the Solar Nebula, a giant cloud of material that is believed to have spawned our solar system. As the Nebula collapsed, its temperature and rotation increased. The increased spin began to flatten the nebula, pressing atoms and molecules together into particles. The hottest point, right at the center, became the Sun. Cooler particles spread to the outer regions and eventually formed planets and moons.

Meteors are thought to be pieces left over from the formation of the solar system and some meteorites have been dated at 4.5 billion years old.