Gravity is said not to act at the molecular level. Brownian motion. Drunken walk.
Oh please. Just because there isn't a unanimously accepted unified field theory yet uniting quantum mechanics with general relativity doesn't mean that fermions magically get to ignore gravity and can do whatever they want. Like a pot of boiling water, if you send them into a gravity well, time dilation will apply the same to them as anything else. This can be seen with atomic clock experiments in space versus those on Earth. Gravity doesn't "go away" unless you ascend to a higher dimension(in theory), and bosons such as the Higgs boson bind fermions with spacetime.
Not to mention gravitational singularities (aka black holes) are smaller than molecules - those tend to have pretty big gravitational effects.......
I think what he's getting at is how at the molecular level the electromagnetic force is roughly ten decillion times stronger than the gravitational force. It's also a frame of reference thing - imagine a cloud of gas hurtling toward a star (thus experiencing an extreme gravitational event). Assuming there actually are molecules (say, a water cloud instead of a gas cloud like hydrogen) - there is a gravitational force between all particles involved at the molecular level, but the electromagnetic force is so much stronger the gravity is irrelevant (again, relative to each other, not relative to the star they're all falling into). Gravity becomes dominant the minute you start going toward the macroscopic, because at that point you have so many positive and negative charges the electromagnetic force cancels itself out.
