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Old 22-09-2011, 03:48 PM
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pmrid (Peter)
Ageing badly.

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Join Date: May 2008
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Quote:
Originally Posted by sjastro View Post
An understanding of special relativity is required here.

At very high velocities approaching and including the speed of light (=c), velocities don't add vectorially.

For example if two objects approach each other at a velocity v, then their approach velocity relative to each other is 2v.

At high velocities their approach velocity is 2v/(1+(v/c)^2)

If each object (photon) approaches each other at a speed c, then the
approach velocity is 2c/(1+(c/c)^2)= c

Regards

Steven
I am going to have to take that on faith alone. It sounds like fancy bookeeping to me I'm afraid.
Peter
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