Earth

Are there other planets like Earth? -

No, we don't know of any other planets exactly like Earth, with its unique life forms. But Earth has similarities to three other planets orbiting the Sun - Mercury, Venus and Mars. All four are made of rock and metal, orbit close to Sun, and have relatively hot surfaces. They are known as the terrestrial or rocky planets.

Life on Earth-

Earth is only place in the Universe where life is known. It is home for 1.5 million distinct forms of life and more are being discovered all time. Earth is just far enough away from the Sun for liquid, water and life exist. If it were any closer, Earth would be too hot, any further away, and it would be too cold. More than 70 per cent of Earth is covered in water. If the planet was perfectly smooth its surface would be  covered with a layer 2.8 km (1.7 miles) deep. Earth has just a right temperature for its water to be liquid. Mercury and Venus are too hot, and their water has evaporated. Most of Mars water is frozen beneath its surface.

-Keva