The+planets

​ The planets​ The planets are bodies in space that travel around the Sun. This is called a solar system. The solar system is one light year across. The Earth is part of the planets of the solar system. There are nine planets in the solar system. One of them is not really a planet. It is Pluto. Astronauts think Pluto is too small to be a planet, so in 2006 it was classified as a dwarf planet. The sun is a million times bigger than Earth! Every planet in the solar system has a moon except Mercury and Venus. Mercury nearly has no atmosphere. The biggest planet in the solar system is Jupiter. If all the planets fit in Jupiter there would still be more space! Mercury is the closest planet to the sun but not the hottest planet. Venus is the hottest planet. It traps the heat that the sun gives out to it. Venus rains acid.