Time Dilation - How does it know which Frame of Reference to age slower?
This has bugged me for years.
According to the theory of relativity, the faster an object moves, the slower time goes for that object, relative to a stationary observer.
However, it is my understanding that motion is necessarily relative to a frame of reference. If you have two objects in space moving away from each other at a combined velocity of 20mph, the rate at which each is moving is totally conditional on what frame of reference you specify.
- If object A is your frame of reference, than object A is moving at 0mph, and object B is moving at 20mph.
- If object B is your frame of reference, the opposite is true.
- If something else is your frame of reference, then the two objects will have some other two velocities, which, when summed, equal 20mph.
If this is true, how does physics know how much to slow down time for each object? It's as if they don't actually have set velocities.