http://en.m.wikipedia.org/wiki/International_Atomic_Time http://en.m.wikipedia.org/wiki/International_Atomic_Time The time we use it based on an average of many

http://en.m.wikipedia.org/wiki/International_Atomic_Time http://en.m.wikipedia.org/wiki/International_Atomic_Time The time we use it based on an average of many clocks. The fact that time passes at different rates at different locations is already account for.