The solar system formed about 4.6 billion years ago. It started out as a huge cloud of gas and dust that began to collapse due to its own gravity. As the cloud of gas and dust collapsed towards its center, it flattened into a spinning disk. Most of the gas and dust got sucked into the middle to form the Sun, and the remaining material formed the planets, which primarily orbit the Sun in the same direction that the disk was spinning. Interestingly, the rocky planets (Mercury, Venus, Earth, and Mars) all formed close to the sun, while the gas giants (Jupiter, Saturn, Uranus, and Neptune) all formed farther away from the sun. This separation occurred because the intense heat and solar wind produced by the sun "blew" most of the gases away from the interior planets, leaving only the rocky material behind.

The sun formed approximately 4.7 billion years ago when a cloud of dust and plasma collapsed from a nebula. The rest of the solar system was part of the disk of dust and plasma that formed the sun, but most of its pieces (like the Earth) didn't form until closer to 4.6 billion years ago.