The Formation of the Solar System

Ideas about the formation and organization of the solar system have changed dramatically over hundreds of years. Modern astronomers have gathered evidence to support the theory that the formation of the solar system took place when a nebula began to contract around 4.6 billion years ago. The particles of gas and dust within the nebula began to rotate and accumulate according to their density. The Sun formed in the center of the nebula with the planets forming around it in order of decreasing density. Today, the Solar System is home to the Sun, eight planets, several dwarf planets, moons, comets, and asteroids. Scientists know of more than 500 solar systems and are constantly discovering more. Given the size of the Milky Way Galaxy, scientists estimate that there may be tens of millions of solar systems or more that all formed in the same way. Some of them might even have habitable planets that can sustain life like planet Earth. Astronomers are looking!