Welcome to Planet Earth,the third planet from a star named The Sun.Earth is shaped like a sphere and composed mostly of rock.Over 70% of Earth's suface is water.The planet has a relatively thin atmosphere composed mostly of nitrogen and oxygen.Earth has a single large moon that is about one-fourth of its diameter and,from the planet's surface,appears almost exactly the same size as the Sun.With its abundance of liquid water,Earth supports a large variety of life forms,including potentially intelligent species such as dolphins and humans.Please enjoy your stay on planet Earth.[APOD]
I believe this is a computer rendering. The only full-earth photo AFAIK is from the Apollo missions in the 70's. Also, this picture is way too sharp and clean. And the atmosphere looks too thick. But I could be wrong. Great picture nonetheless. Good desktop image :)