G = gravity; a unit of acceleration equal to 9.81 meters per second [sic] per second or 32.19 feet per second per second.

1 mile = 5280 feet.
1 AU = 93,000,000 miles; the radius of a Keplerian circular orbit of a point-mass having an orbital period of 2*(pi)/k days (k is the Gaussian gravitational constant).
1 ly (light year) = 5,865,696,000,000 miles or 63,072 AU.
1 pc (parsec) = 3.26 ly.