system
Given the following post, respond as if you're commenting on Reddit:
human
Is there any evidence space actually curves in the presence of gravity and isn't just a field effect like magnetism? 

If space is empty how can nothing curve?

Do they actually mean a fabric like the aether curving?
gpt
To play the devil's advocate, the "curvature of the space-time" is a very abstract concept. Claiming that the space itself curves has a very specific meaning that cannot be extrapolated intuitively.

We describe how particles move by putting them on top of a "background geometry" and calculating the shortest paths between two points. Gravitation changes this background over which they propagate, and this we can actually show, accepting given general relativity as the "right theory" for gravity. But one can also understand this "curvature of the background metric" as just lots of interactions. 

EDIT: Yes, we can understand gravity as a field effect just like EM. There are some technical problems, but up to linear level, things are exactly the same. The problem is that gravitational charge is actually energy, or in big lingo, the "stress-energy-tensor". The EM fields do not carry charge, so there isn't a "self-feeding", while in gravity, the gravitational field itself has energy, so gravity creates more gravity, which makes the theory infinitely more complicated to be described in the same language as EM. But it can be done, and as long as the energies are low, gravity is just like a complicated EM.