What is a solar system?

Our solar system consists of the Sun and the planets orbiting around it. The solar system formed approximately 4.6 billion years ago from a molecular cloud that lead to the creation of the star that is our Sun. Once the Sun was formed its immense gravitational pull created the planets over several millions of years by smashing matter into each other, until everything began to look the way it does today.

The solar system contains 4 terrestrial planets made mostly of rock and metal. These are, in order, Mercury, Venus, Earth and Mars. After these come four other planets known as the gas giants: Jupiter, Saturn, Uranus and Neptune. These outer planets are considerably larger than the inner planets and are composed almost entirely of gas. Jupiter and Saturn have hydrogen and helium, while Uranus and Neptune are composed of ices: ammonia, methane and water.

Until recently it was believed that the solar system had 9 planets, with Pluto being the ninth, but the discovery of Haumea, Makemake and Eris caused it to be pronounced as a dwarf planet along with the others. These are labeled as trans-Neptunian objects, which, as the name suggests, can be found farther from the Sun than Neptune.

The solar system however does not only contain planets. The asteroid belt between Mars and Jupiter contains rock and metal and is referred to as the main belt, because it is not the only place in the solar system where asteroids can be found. Comets, centaurs and interplanetary dust also form part of the solar system and can be found roaming freely in some regions.

Of the solar system planets, 6 have natural satellites as well as 3 dwarf ones. Solar system exploration and observation has made human understand it better and study every element that can be found in the solar system. Solar system pictures are available with more information on every containing element.