How to count the tangential velocity?

Question

I was wondering about how to count it, what is it exactly. Can we say that some objects move with the velocity bigger than c? Eg. when a supernova explodes, we can observate it from a distance on a screen. When we add more details about the situation and the shape of the screen, we can say about the velocities bigger than c. What are those details? :)

Answer 1

Hi. There is a star being watched very closely by astronomers because it may be a new type of supernovae. The light 'echoes' from reflecting gas and dust seem to move at a speed greater than 'c'. This is not due to anything actually MOVING. Just the lit up areas expand in a tangential fashion. : http://www.habitablezone.com/space/messages/444552.html