John Carlos Baez on Nostr: In general relativity, when space is 2-dimensional, a particle creates a singularity ...

In general relativity, when space is 2-dimensional, a particle creates a singularity that's a cone point. And here's the cool part: the angle deficit of that cone is proportional to the *mass* of that particle!

So there's an upper bound on mass, since the angle deficit can't be > 360°. That's cool.

Now suppose space is not only 2-dimensional but topologically a sphere. It's flat except at cone points, which are particles. Can you visualize this?

Yes you can! Any convex polyhedron gives an example! Its geometry is intrinsically flat except at the vertices, which are cone points.

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