Combining Time Dilation from velocity and gravity

1. Sep 28, 2009

edgepflow

Suppose a stationary observer was watching a space ship travel near the speed of light and close to a massive black hope so that time dilation from the relative velocity and gravity of the massive object are significant.

Assume that the ship is moving at 0.866c so that for every hour that passes for the ship's astronauts, 2 hours pass for the for the stationary observer per special relativity.

Now also assume, that the ship is close enough to the black hole so that for every hour that passes for the ship's astronauts, 2 hours pass for the for the stationary observer per general relativity.

So the question is: what would be the combined effect?

P.S. I meant to post this in the Relativity Forum!

2. Sep 28, 2009

Janus

Staff Emeritus
Moved

3. Sep 29, 2009

Ich

So in 1 hour of your time, you see stationary clocks at the ships position tick 1/2 hour.
They see the ship clock tick 1/4 hour - and so do you.

4. Sep 29, 2009

edgepflow

Thanks for the reply Ich. It looks like the combination is multiplicative. I also noticed this under Similar Threads that discusses this.

https://www.physicsforums.com/showthread.php?t=299318

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