1. Dec 28, 2007

### jujufactory

Two objects, A and B, are moving past each other at close to the speed of light relative to each other.

So far so good.

Object A looks at object B and sees object B fly by at close to the speed of light. Object A figures time dilatation takes effect and concludes the clocks on B are moving more slowly than on A.

Object B looks at object A and concludes the same thing.

A while later, the two objects meet up with each other and compare clocks. Are their clocks indicating the same time or different times? Which clock is ahead? If none of the clocks are ahead, then what happened to relativity?

This ongoing paradox seems to undermine the entire theory. Could somebody clear up this paradox. Thank you.

Last edited: Dec 28, 2007
2. Dec 28, 2007

### jcsd

There's no paradox, whilst it is counterintutive that both should see each other's clocks running slower than their own, it's not inconsistant.

When they meet up for a second time their clocks can show either the same or different amount of times elapsed. This depends on how they meet up (i.e. the details of the accelartion, path, etc). Generally speaking if they maintain symmetry between each other they will show the same amount of time elapsed, if they break the symmetry then they will show a different amount of time elapsed.

3. Dec 28, 2007