Q&A: why gravity is not a force
why gravity is not a force
Question
https://youtu.be/XRr1kaXKBsU
It reminds me of the last faith class where you spoke about the existence of the force of gravity
Answer
It’s well known. That is the whole idea of general relativity: instead of speaking about a force, one speaks about the curvature of space. But that is one of the reasons why, for now, it is impossible to reconcile relativity with quantum theory, because quantization of a gravitational field yields gravitons, which are particles that carry the force of gravity (just as photons carry the electromagnetic force). That means there is a gravitational force/field. So people try to quantize spacetime itself, and that takes us to strings. Work is still ongoing on this.
But at the bottom line, geometry and field are just two forms of description of the gravitational phenomenon. It is not clear that there is a right and a wrong here.
For our purposes, what matters is the relationship between the theoretical description and the entities that give rise to that description. So I could also have spoken about the electromagnetic field, and there it is clear that there is a force field. And even in the gravitational context, even if you accept the picture that emerges from general relativity, the description is still created by something in reality. In this case, it is not a force but spatial curvature. What practical difference does it make? The theory not only describes; it also makes claims that explain and generate the description. And that was my point there.