If two objects are traveling away from each other at the speed of light...

[Lightmeow]

So lets say you have two objects... They are traveling away from each other at, say 90% the speed of light. Wouldn't that mean that they, from the frame of veiw of each object, traveling away from each other at 180% of the speed of light? This breaks the rule that says that you can't travel faster than the speed of light. So how does this work?

 

Thanks in Advance

[Strange]

I suspect you mean that they are both travelling away from you (for example) at 90% the speed of light, so in your frame of reference they are separating at 180% the speed of light?

 

The thing is, velocity does not add linearly (even though it seems to at everyday speeds). So each object, from its own frame of reference, sees the other moving at about 99.4% the speed of light.

 

Actually, 99.4475138121547% according to this page: http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/einvel2.html

[StringJunky]

I suspect you mean that they are both travelling away from you (for example) at 90% the speed of light, so in your frame of reference they are separating at 180% the speed of light?

 

The thing is, velocity does not add linearly (even though it seems to at everyday speeds). So each object, from its own frame of reference, sees the other moving at about 99.4% the speed of light.

 

Actually, 99.4475138121547% according to this page: http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/einvel2.html

Why is it not 90% the SOL from either frame because I thought the SOL was same for all inertial observers? Obviously I'm missing something.

 

Edit. Just realised that they are NOT travelling at the SOL. Duh!

Edited December 11, 2014 by StringJunky