Solar System Homepage Earth is the third planet from the Sun and is the only planet we know of that has air and water and is able to support life.
Earth supports many forms of life - on land, in the water and the air.
Our air and oceans were formed from gases that seeped from the Earth as it cooled after formation. The Earth has a solid core made up mainly of iron and nickel. When the Earth had just been formed, over 4 billion years ago, radioactive material in its interior was generating a great deal of heat. The heat couldn't dissipate quickly enough and the interior grew hotter and hotter. After another billion years or so, the interior had become so hot that the iron melted and sank to the centre, forming the core.