Mercury, Venus, Earth and Mars are the four planets that are the nearest to the Sun. They are called the inner planets. All these planets are made of rocks. Each of the inner planet has an atmosphere. The atmosphere of Earth contains air which is suitable for living things to survive. The atmosphere of the other inner planets is very thin and poisonous to living things.
It is too close to the Sun. The temperature is too hot to support live.
A great amount of the heat from the Sun is trapped in its atmosphere. This makes it hotter than Mercury.
It has water, air and a suitable temperature to support life.
Almost all of its water is frozen. Scientists have not found any life there.
The Outer Planets
The outer planets are Jupiter, Saturn, Uranus, Neptune and Pluto. They are mainly made of gasses. Their temperature is too cold to support life.
It is so big that all the other planets could fit inside it.
Saturn has three wide rings. They can be seen with a telescope.
Unlike the other planets, Uranus is lying on its side as it goes round the Sun.
Neptune is covered with a blue ocean of liquid methane.
Pluto is very cold because it is very far from the Sun.
The position of Earth from the Sun is just right for it to receive enough heat to support life. It has water and air too. These are needed to support life. The other planets either receive too little or too much heat. They alo do not have a suitable atmosphere for living things to survive.