The solar system formed approximately 4.6 billion years ago from a giant cloud of gas and dust called the solar nebula. As the nebula collapsed under its own gravity, the center became increasingly dense, eventually forming the Sun. At the same time, material in the outer regions of the solar nebula began to clump together due to gravitational attraction. These clumps of material, called planetesimals, collided and stuck together, eventually forming protoplanets. Over time, these protoplanets continued to grow through further collisions and accretion of material. Through a process known as planetary differentiation, the protoplanets began to differentiate into layers based on density. The heavier materials sank to the center to form cores, while lighter materials rose to the surface. This led to the formation of the terrestrial planets like Earth, Mars, Venus, and Mercury. In the outer regions of the solar system, where temperatures were cooler, gas giants like Jupiter and Saturn formed. These planets captured large amounts of hydrogen and helium gas from the solar nebula, giving them their massive sizes and thick atmospheres. Overall, the formation of planets in the solar system was a complex and dynamic process that occurred over millions of years. This process continues to shape our understanding of planetary formation and evolution in our universe.