# High velocity

1. Sep 5, 2011

### keepit

i'm assuming that a high velocity object is representative of a high energy and therefore has a high amount of gravity. Is this gravity what causes time to slow down gravity such a system?

2. Sep 5, 2011

### PAllen

No. This is a symmetric, relative, effect in special relativity. Gravity is irrelevant. Note that gravitational time dilation is asymmetric: if A observes B's clock is slow, B observes A's clock is fast. On the other hand, if A and B have rapid relative motion, each observes the other's clock to be slow. Further, the dilation is independent of mass (in contrast, gravitational time dilation proportional to mass, everything else held constant).