There's quite a lot of arguments back and forth about it through this whole thread if you really want to dive into it. The cliff notes is effectively that gravity is not a force in GR. It is considered a force in newtonian physics, and might be a force again if we ever make a Theory of Everything. Gravity is fairly akin to a force in string theory, so if they do end up being right, gravity would be a force. If the Loop Quantum Gravity folks are right, gravity will remain not a force. If it's some other theory, who knows what it'll end up being.
I'm not about to comb through threads on Hacker News and synthesize a theory from comments by people who may or may not know what they're talking about. But thanks.
johncarlosbaez is about as real deal of a physicist as they come, and pdonis is a nuclear engineer with a degree from MIT who is a longstanding mentor on the largest physics discussion forum in the world. I'd recommend reading their posts if you are curious about the take on this question from people well educated in the subject.
ScienceClic on Youtube has amazing videos on this topic as does Veritasium. Einstein's happiest thought helps with understanding this. He thought that there would be no discernible difference between what a man felt while falling off a ladder (let's not factor in air resistance) and what a person in 0g space felt.
We are actually "accelerating" upwards at a constant rate that is equal to what we feel and many think of as gravity. This is because spacetime is curved by the mass of the earth.
Think of a grid being distorted or squeezed / pinched. The distortion pinching is "gravity". Everything in the grid still travels in a straight path relative tot he lines on the grid but since the [spacetime] grid is pinched, it looks as if it is not on a straight path.
