system
Given the following post, respond as if you're commenting on Reddit:
human
Relativity says that the phenomenon we know as gravity is in fact the curvature of space. What about the other fundamental forces? Is there a theory that tries to explain them as the curvature of space as well?

My knowledge of physics very elementary, so please correct me if my question doesn't make any sense!
gpt
There actually is an approach that would explain the other forces that way, although it also involves having additional dimensions of spacetime.

There's something called the Kaluza-Klein mechanism (named for work of Kaluza and of Klein in the 1920s, though Nordstrom actually first did something very similar in 1914).  The idea is that we start with a higher dimensional theory in which the only force is gravity, and then require that the extra dimensions be so small in extent that we basically can't see them.

What would our world look like if this was the case? Well, of course we'd only see four dimensions (three of space, one of time), and there would be gravity in these four dimensions, but it turns out there would be some additional remnants of this higher dimensional world. These remnants would appear to us as additional forces, and indeed it is mathematically possible to construct the electromagnetic, weak, and strong forces in precisely this way. Thus, higher dimensions offer an appealing avenue for unifying gravity with the other forces; these other forces would thus be explicable in terms of the warping of spacetime -- but the full, higher dimensional space-time, not just the four dimensions with which we are familiar. Whether we can do so in an empirically successful way remains to be seen.

With one extra dimension, you can get electromagnetism (but not in a successful way, as you also get one other artifact, a massless spin 0 particle that is experimentally not observed), whereas you need at least 7 extra dimensions (or only 6, if you have strings rather than particles) to incorporate the weak, strong, and electromagnetic forces.

Is this the way the world works?  We don't know, but a lot of people who work on approaches to unification of gravity with the other forces do find this mechanism attractive, and certainly include it as one of the tools in their toolbox.