Scott Air Force Base, IL Demographic Information *. There is no Census data for the city of SCOTT AIR FORCE BASE, IL. We have pulled information for the ZIP Code 62225 instead.
A light-year is a unit of distance. It is the distance that light can travel in one year. Light moves at a velocity of about 300,000 kilometers (km) each second. So in one year, it can travel about 10 trillion km. More p recisely, one light-year is equal to 9,500,000,000,000 kilometers.
It's how far light can travel in one of our years (that's a Julian year, and not a leap year...) The distance from the Earth to the edge of the visible universe is about 46.5 gigalight-years in any direction; this is the comoving radius of the observable universe. http://en.wikipedia.org/wiki/Light-year (RMG's missed a 'light' in his post above. ...