Hi everyone, I've been reading posts here occasionally, and have been impressed with the amount and quality of knowledge that is being shared. I've just registered, and as my first thread I thought I would post some questions / thoughts that have puzzled me for a long time, related to gravitation and general relativity. Now, I'm a complete amateur, so please view the questions as such! They probably seem quite naive to an expert, but to someone like me, they are anything but straightforward. So here goes: 1) My understanding is that we need a unified theory combining general relativity with quantum effects because the two are incompatible at GR singularities. So if string theory is a serious candidate for such a theory, what does string theory predict at the singularities? Same with any other attempts at a unified theory? Do they make some physically sensible statements about what really happens, say, at the centre of a black hole? 2) I've been told that general relativity says there is no force of gravity, but that things tend to 'go straight' in 4D spacetime. The geometry of spacetime itself is warped by mass / energy, which is why it seems like there is a force of gravity affecting trajectories of objects. But I'm pretty sure I've occasionally seen gravity described as a force in GR texts. And if it's not a force, then why do we want to find 'gravitons' that supposedly transmit the force of gravity? So is gravity geometry or force? Or are the two really indistinguishable, and just two ways to look at one thing? 3) With newtonian gravity, we can say that in a particular spot between the earth and the moon (One of the Lagrange points), the gravitational forces from the two objects cancel out. What does this mean in a general relativity context? Does it mean that in this location, spacetime geometry is flat? And if so, does this mean that if two black holes were orbiting each other at a distance of just slightly over their Schwarzschild radius, would spacetime be flat halfway between them? Could I just float at that point without having to worry too much about being sucked in? 4) This is a bit of a silly one, but it puzzles me! So Newtonian gravity is just an approximation of general relativity. But how on earth does GR simplify to the beautifully concise and sensible newtonian gravity law? I'm not sure how to explain what I mean, but to me, Newton's law of gravity makes intuitive physical sense: the force of gravity is proportional to both masses, and inversely proportional to the square of their distance. It makes sense! I'm just amazed that a law that is 'wrong', and as such does not really have any proper physical justification (I assume) can seem so right!