- #1

- 47

- 5

Is this parameterization correct? -

##r(t) = R = \mbox{const}##

##\theta(t) = 0 = \mbox{const}##

##z(t) = ct##

##t = t##

This is supposed to be the null geodesic curve in the case of a light ray, emitted at point {##r=R,\theta=0,z=0,t=0##} parallel to the ##z-##axis in flat spacetime. I'm posting because I am unsure if the time ##t## can serve as an affine parameter.

Are there better parameterization choices here?