The planet on which we live is third in order from the local star Sol.
This planet is called Earth.
Earth has an albedo of 0.39, meaning 39% of the sunlight striking the Earth and
it's atmosphere is reflected back into space. The Earth has an equatorial
diameter of 7928 miles, and is an average of 93 million miles from Sol.
This distance is also the length of one Astronomical Unit. Planetology is
a branch of astronomy dealing with the condensed matter of the Solar System,
and especially with the planets and their moons. The earth has a single
natural moon named Luna.
