A gravitational field does not depend on the mass of the thing being attracted. The earth accelerates things at 9.8 m/s^2, regardless of the thing's mass. Give

A gravitational field does not depend on the mass of the thing being attracted. The earth accelerates things at 9.8 m/s^2, regardless of the thing's mass. Given that, why shouldn't light also fall at 9.8 m/2^s as it passes the earth? That would be extremely hard to measure, but if you extrapolate the phenomenon, you get gravitational lensing. 18th century scientists wouldn't have known that light was a zero-mass particle. The results of the calculations are ambiguous with a zero-mass particle (a=F/m is a divide-by-zero error). But if you don't know about that, you can just wonder if light particles (or waves, or whatever) also gets deflected at the same acceleration as ordinary matter. Light in fact doesn't accelerate at a, but at 2a in a gravitational field. The Eddington experiment in 1919 agreed with that figure, disproving the Newtonian version.