Verified answer

When you consider the distance the sun is from us, it is essentially a single point in the sky, a light wave will move in a straight line from that point and will not naturally spread out unless passing through a particular medium that makes them. Picture holding a piece of paper with a hole in it between a lightbulb and a wall. The bright spot on the wall will get smaller the farther the lightbulb is moved away from the paper, because the light is coming from a seemingly more singular source.

The answer is in the question, the light is a ray.

That is not the physics answer, but it sorta is.