What if light were influenced by gravity?

[FactChecker]

Now that one really is a straight line!

Well, yes. Poor example. I should have used the example of a ball thrown horizontally. But even falling straight down (in the Earth-centered-Earth-fixed coordinate system) is not straight in a non-rotating inertial coordinate system, so it is an example of something.

 

[Herman Trivilino]

A straight line is a mathematical concept.

Okay. But so are all curved lines.

Doesn't actually exist in our universe if you take into account all influences on a moving object,

What is your point? That objects don't move in straight lines or curved lines, either? No, I doubt it. I think the issue is that the mathematical concept is a model, and the motion of the object is the thing being modeled. Of course the former is an approximation of the latter.