This is how lines are defined in parametric equations! Essentially just a parametric equation of a slowly scaled up vector.
The equation for lines are the same format, but there is a slight difference here in that you can't have light "behind" the origin, whereas a light is infinite. This is denoted by how $$0 \leq t < \infty$$.
I meant 0≤t<∞0 \leq t < \infty0≤t<∞ :/ latex not doing what I want again
Are rays used in other applications besides graphics? Because it’s essentially a vector with an extra dimension(s) for its origin point. Also how are these represented with homogenous coords