3 ms·

I don't think it makes sense to say that the speed of a photon is c "in a direction", since speed is a scalar quantity. (correct me if I'm wrong, I'm terrible

by xnxn 14y ago

I don't think it makes sense to say that the speed of a photon is c "in a direction", since speed is a scalar quantity. (correct me if I'm wrong, I'm terrible at physics!)

shardling 14y ago
Here, speed is a measure of the magnitude of velocity. It's perfectly acceptable to describe velocity (or a component thereof) as speed in a particular direction.