What led to the formation of the solar system?

Answer 1

About 15 billion years ago a huge explosion started the expansion of the universe. This explosion is known as the Big Bang. At the point of this event all of the matter and energy of space was contained at one point. The Big Bang created our universe that now consists of our own Milky Way Galaxy and many other galaxies. Also, the big bang made every planet, star, matter and energy in the universe. Some evidence to support the big bang theory is that all the galaxies are moving away from each other.

The formation and evolution of the Solar System is estimated to have begun 4.5 billion years ago. A nebula (a huge dust cloud left over from the original stars of the galaxy) started collapsing under its own gravity. Over a period of millions of years, it shrank, heating up as it contracted and compressed in the center. Then the matter around the center fell inward toward the spinning center, and flattened into a rotating disk.

As the disk got thinner and thinner, particles began to stick together and form clumps. Some clumps got bigger, as particles and small clumps stuck to them, eventually forming planets or moons . Near the center of the cloud, where planets like Earth formed, only rocky material could stand the great heat. Icy matter settled in the outer regions of the disk along with rocky material, where the gas giant planets like Jupiter formed. As the cloud continued to fall in, the center eventually got so hot that it became a star, the Sun, and blew most of the gas and dust of the new solar system outward.

The larger clumps (planetesimals) collided and combined to form planets, all of which were originally molten rock. The planets swept loose dust and gas from their orbits, and began to cool, forming atmospheres. Smaller chunks either broke up into smaller chunks or were drawn together to form asteroids and moons.