Expert: Jayendra Upadhye - 10/31/2005

Question
If person A moves close to the speed of light and person B does not, does then reletive time slows down for person A when compared to person B.  For example maybe 5 minutes would pass for person A and fifty years would pass for person B.  If so, if we measure light from our reletive time, as 1 billion years for instance, isn't the light, which is traveling at the speed of light, actually much younger?

Answer
Hi,
yes & No! Meaning "younger" is not applicable to both frames of reference but is only relative.

What is light a few seconds old for the guy in the fast moving frame of reference, is light 50 years old for the slower guy!

However the distance travelled by both people is SAME.
For the faster guy, the 50 lightyear distance will become shortened (lorentz contraction) which HE will travel at the speed of light for "THE SAID MINUTES" of HIS travel, and thus he will finish his journey of SAME distance in absolute space. (space wherein special relativity need not apply as objects are moving in newtonian limits..ie very slow non-relativistic speeds).
Hope that rersolves your question.
Jayen