There is a lot can be written about earth, this is what wiki says -
Earth is the planet we live on. It is the third planet from the sun in our solar system. It is the only planet known to have life on it. Lots of scientists think the earth formed around 4.5 billion years ago. It is one of four rocky planets on the inside of the Solar System. The other three are Mercury, Venus and Mars.
The large mass of the sun makes Earth move around it, just as the mass of Earth makes the moon move around it. Earth also turns around in space, so that different parts face the sun at different times. Earth goes around the sun once (one "year") for every 365¼ times it turns all the way around (one "day").
Earth is the only planet in our solar system that has a large amount of liquid water. About 71% of the surface of Earth is covered by oceans. Because of this, people sometimes call it "blue planet". Because of its water, Earth is home to millions of species of plants and animals.