If our space is a surface, it is in effect a space within a larger space, which oddly enough isn’t a new idea. In 1919, Kaluza noticed that Maxwell’s equations could be derived from relativity theory if Einstein’s equations had another dimension. This essentially unified quantum theory and relativity, but another physical dimension made gravity vary as an inverse cube, so the solar system would collapse. Kaluza’s extra dimension was ignored because physical space has only three dimensions, so when mathematicians discovered that light was explained by complex numbersthat rotated into a fourth dimension, they called it an imaginary dimension, which was accepted.
Klein then tried to rescue Kaluza’s extra dimension by suggesting that it was curled up in a tiny circle that went nowhere, so it existed but did nothing. This was again ignored, until years later it was reused by string theory to explain its extra dimensions, but why would nature have dimensions that do nothing but make our equations work?
Space as a hypersphere surface resolves these confusions as the extra dimension isn’t physical and there is only one. Instead of a dimension inside space that does nothing, it is a dimension outside space by which it is observed. Just as we view 2D screens from a third dimension, space as a 3D screen is viewed from a fourth dimension.
Some physicists have recognized that our world could be a brane within in a higher-dimensional world:
“Physicists have now returned to the idea that the three-dimensional world that surrounds us could be a three-dimensional slice of a higher dimensional world.” (Randall, 2005) p52.
Since this extra dimension is sequestered from our space, it doesn’t alter gravity or charge (Randall & Sundrum, 1999). If this dimension was physical, we could walk out of this world, but we can’t, any more than an avatar can walk out of a game screen. Space as a surface means that, like a goldfish in a bowl, everything we do physically is contained. It also means that matter is not everything, as it is contained within a space that is not everywhere.