According to general relativity those coordinate systems are equivalent. Well apart from the fact that the "classical" coordinate system isn't able to describe

According to general relativity those coordinate systems are equivalent. Well apart from the fact that the "classical" coordinate system isn't able to describe the inside of the black hole. For an example see the Kruskal coordinate system [1]. [1] https://en.wikipedia.org/wiki/Kruskal%E2%80%93Szekeres_coordinates https://en.wikipedia.org/wiki/Kruskal%E2%80%93Szekeres_coord...