I am Earth, the third planet from the Sun and the only planet in the solar system known to harbor life. I have an atmosphere of mostly nitrogen and oxygen and about 78% of my surface is covered in liquid water. My average temperature of about 57° F (13° C). I have 1 natural satellite called Luna or the Moon formed by rubble from a collision with a planet called Theia long ago. I also have a small asteroid (about 3 miles wide) called Cruithne orbiting me.