Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Bill S on 26/12/2010 20:43:09

Title: Is it only the speed of light in a vacuum that is constant for all observers?
Post by: Bill S on 26/12/2010 20:43:09

If, for example, light is travelling through a medium that reduces its speed to 0.99c, would an observer travelling in the opposite direction at 0.01c measure the speed of the approaching light as c, or 0.99c? 

Title: Is it only the speed of light in a vacuum that is constant for all observers?
Post by: QuantumClue on 26/12/2010 20:50:44

Always the speed of light. The speed of light never changes, no matter what speed you move at.

Title: Is it only the speed of light in a vacuum that is constant for all observers?
Post by: QuantumClue on 31/12/2010 05:06:22

Bill I must apologize. I don't believe I read the OP correctly at all, because my answer hardly fits into your question at all. Sorry about that. I take back what I said in light of it.

Title: Is it only the speed of light in a vacuum that is constant for all observers?
Post by: JP on 31/12/2010 05:09:00

This is the double post that Bill was talking about.  In order to keep things tidy, I'm redirecting traffic to the livelier version of this thread:

http://www.thenakedscientists.com/forum/index.php?topic=36290.0;topicseen