Time Scales

There is also a time scale associated with natural units that is related to the ones already discussed. The smallest scale is the Planck time, which is 10^{-43} sec, and the largest observed one is the age of the universe, which is about 10^{62} in Planck units. (Note that this is consistent with the fact that the speed of light is 1 in natural units, and the size of the universe is 10^{62} because distance, of course, equals speed multiplied by time).