Relativity

According to theory of relativity, for a person the rate with which time passes decreases with speed, with respect to a second person who is at rest. But, the person who is traveling at a very high speed will experience the second person to be traveling at the same speed but just in the opposite direction, and that means the rate with which time passes for the second person also decreases with respect to the first person. Does this really happen?
- Anurag (age 17)
India

Yes, it does. However, in order for two observers who had the same time initially to come back together and compare times (without having to make perspective-dependent corrections for how long light takes to get from one to the other), at least one of them must accelerate. Unlike the effects of relative velocity, the acceleration effects are not symmetrical. At the end, they both agree on which (or neither) aged more.

Mike W.

(published on 09/03/2008)