4.6 billion years ago, a cloud of gas and dust collapsed under the force of its own gravity to form our solar system.With the Sun at its center, glowing, the planets had not yet formed. The Sun, a G-type Population 1 star, shines brightly with a surface temperature of about 9,400 degrees, 5,500 Kelvin, and a lifespan of about 10 billion years.

Big History Thresholds: 1=Big Bang | 2=Stars&Galaxies | 3=Chemicals | 4=Solar System | 5=First Life | 6=TI | 7=Agrarian | 8=Science

Formation of Solar System and Earth: The 4th threshold is the forging of our Solar System.