The solar system encompasses the sun, the eight planets, dwarf planets and smaller objects orbiting the sun as well as the moons that orbit the planets. The solar system formed about 4.6 billion years ago when a giant molecular cloud suffered a gravitational collapsed. People originally believed that the earth was the center of the universe and did not recognize the solar system's existence. Nicolaus Copernicus was the first to suggest that the sun was the center of the solar system and not the earth. The telescope's invention led to the discovery of planets and moons that could not be seen with the naked eye. Here are some facts about Solar System, you never know before.
- 99.86% of the solar system's mass is contained within the sun while the remaining mass is made up of the eight planets.
- Of the solar system's eight planets, Mercury, Venus, Earth and Mars are the four planets are made of rock and metal.
- Jupiter, Saturn, Uranus and Neptune are made up of mostly hydrogen and helium and are considered to be gas giants.
- The rock planets are the four closest to the sun and the gas planets are the four farthest from the sun.
- The sun is the solar system's star.
- Nobody knows for sure how many dwarf planets exist in our solar system. Some of the known dwarf planets are Ceres, Pluto, Haumea, Eris and Makemake.
- Within our solar system are asteroids, which are minor planets circling the sun in an asteroid belt.
- When Pluto was discovered in 1930 it was classified as a planet, making it the ninth planet in the solar system. However when the formal definition of a planet was established, Pluto was reclassified as a dwarf planet.
- In 2012 NASAs Voyager 1 is believed to have reached the transition zone leading to the solar system's outer limit.
- The solar system exists within the Milky Way. The Milky Way is a spiral galaxy with about 200 billion stars and a diameter of 100,000 light years.
