Does SR preserve the direction of light?

[jk22]

does SR change the direction of light and if yes is it then possible to find a transformation keeping the velocity of light invariant and not only its speed ?

 

[Dale]

does SR change the direction of light and if yes is it then possible to find a transformation keeping the velocity of light invariant and not only its speed ?

I think just the identity transformation.

 

[PeterDonis]

Any Lorentz boost will leave invariant the direction of light beams that are directed along the same axis; but it will change the direction of light beams that are not directed along the same axis. So a Lorentz boost along the x-axis would not change the direction of light beams traveling along the x axis; but it would change the direction of all other light beams.

Also, even light beams whose directions are not changed by a Lorentz boost will have their frequency changed.