THE SOLAR SYSTEM

SOLAR SYSTEM The solar system consists of eight planets and their satellites. There are also comets, asteroids and meteoroids. All the planets revolve around the sun in nearly elliptical orbits. The planets can be classified into two groups in terms of their size and position. The first group consists of the two giant planets, Jupiter and Saturn, and the two smaller planets, Uranus and Neptune. They all lie beyond the orbit of Mars and are called outer planets. The second group consists of the inner planets: Mercury, Venus, Earth and Mars. Mercury and Venus lie within the orbit of Earth and are called inner planets. Mercury, Venus, Earth and Mars are called terrestrial planets because they all have solid surfaces. Jupiter and Saturn, with their dense atmospheres, are called gas giants. Uranus and Neptune are called ice giants. Mercury is the closest planet to the sun. It has no atmosphere and very little water. Mercury is the smallest planet in the solar system and it rotates very slowly. Venus is the second planet from the sun. It has a dense atmosphere and is very hot. Venus rotates slowly, but in the wrong direction. Earth is the third planet from the sun and the fifth largest in the solar system. It has a thin atmosphere and is the only planet with liquid water. Mars is the fourth planet from the sun. It is the second smallest planet and has a thin atmosphere. Mars has two moons, Phobos and Deimos. Jupiter is the fifth planet from the sun. It is the largest planet in the solar system and has a dense atmosphere. Jupiter has 16 moons. The four largest moons are Io, Europa, Ganymede and Callisto. They are called the Galilean moons. Saturn is the sixth planet from the sun. It is the second largest planet and has a dense atmosphere. Saturn has 18 moons. The largest moon is Titan. Uranus is the seventh planet from the sun. It is the third largest planet and has a thin atmosphere. Uranus has 27 moons. The largest moon is Titania. Neptune is the eighth planet from the sun. It is the fourth largest planet and has a thin atmosphere. Neptune has 14 moons. The largest moon is Triton.  

There are also comets, asteroids and meteoroids in the solar system. Comets are small, icy bodies that orbit the sun. Asteroids are small, rocky bodies that orbit the sun. Meteoroids are small, rocky bodies that enter the Earth's atmosphere.