The solar system, at the edges of Orion’s arm from the Milky Way, our galaxy, is the solar system where there is the Earth. In the solar system, there are 8 principal planets, which are divided into two different planet types, existing a third type with different characteristics than the two last.
1 – The rocky planets
The rocky planets, or also named telluric planets, are the 4 planets that are the closest to the Sun. The 4 rocky planets are, in order to their proximity to the Sun: Mercury, Venus, The Earth and Mars. As they are the closest of them to the Sun, Mercury, Venus, The Earth and Mars are also sometimes named the interior planets.
- The telluric planets are mainly characterized for being formed from silicates, that to say, from rocks.
- These planets are also those that have a bigger density, as they are formed from rocks.
- They are also characterized to have a mainly solid surface, on the contrary to the gaseous planets, which have gaseous or liquid surfaces. The Earth is the only rocky planet from the solar system which has an active hydrosphere, that to say, that it has water on and behind the surface.
2- The gaseous planets
The gaseous planets are the type of planets that go after the telluric planets, and are the biggest type of planet in the solar system. They are also called exterior planets, as they are farther away than the rocky ones. The 4 gaseous planets from which is formed the solar system are in order to their proximity to the Sun: Jupiter, Saturn, Uranus, and Neptune. The two last of them, Uranus and Neptune, are also named frozen planets, as they are formed by a big quantity of ice and water particles.
– The rocky and gaseous planets are separated by the asteroid belt, situated between the orbits of Mars and Jupiter.
- These giant planets haven’t a defined surface, and they are mainly made of helium and hydrogen.
- The gaseous planets are those that have the biggest amount of moons and rings. For example, Jupiter has 79 natural satellites, and Saturn has 59 moons.
- Their nuclei are very dense, but they have, in general, a low density.
3 – The dwarf planets
The “dwarf planet” term is used since 2006, afterwards to the discovery of celestial bodies that were further away from Jupiter’s orbit, and that they were comparable to Pluto’s size. Since then, this term has been used a lot to describe celestial bodies from the solar system, and it had influenced the ancient system for the qualification of planets, which affirmed that in the solar system there were 9 planets, as Pluto was considered a planet.
The only dwarf planet in the solar system which is situated in the asteroid belt is Ceres. The other ones, like Pluto, Makemake, Haumea, or Eris, are situated further away than Jupiter’s orbit.
- The dwarf planets have an almost spheric shape which is more pronounced than the rest of the planets.
- These planets are orbiting, like the others, around the Sun, but mainly in a further orbit than Jupiter’s.
- They share their orbiting space with other bodies of similar size.