[kosciusko51]

Does particle-free radiant energy carry a physical force, or does it just convey heat energy?

Yes, see Radiation Pressure.

[zeestephen]

Thanks for the link.

I have always struggled with the basic concepts of physics, probably because they have no visible reference points.

The photon - a massless particle that can somehow acquire momentum and turns into a wave whenever it is convenient for the mathematics.

Hard to believe we have literally created the modern world based on ideas like that.