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Sciencepone of Science!
"@redweasel":/1385850#comment_7279164
Unless you've seriously studied this stuff for years and are an absolute genius, I don't think you'll find major revisions to it based off a few minutes of thought.
The reason they're confined to these three dimensions is because the endpoint of every string is some other n-dimensional brane.
See, it's kinda a misnomer to call them "branes" and "strings", really branes are just strings but higher-dimensional ones, and strings are just 1-dimensional branes.
Baryonic matter is all composed of strings that have their endpoints on our brane. Gravity is the exception - I think, iirc, it's because gravity is described by a tensor field rather than a vector field, or something like that - this has something to do with the formulation of Superstring theory that means that gravity would have to be a string with another 1d string attached rather than our 3d brane, meaning gravity is free to bleed into higher dimensional space, thus it wouldn't follow the inverse-square law until it "saturates" the higher dimensions, so you could see it bleed into the higher dimensions over short distances.
I don't know this for sure, but I'm guessing that might actually have something to do with why they thought they might make black holes in the LHC - but the main thing is it'd explain why gravity is so much weaker than the other fundamental forces.
But the theory is very much built on the necessary condition that the strings vibrate through the full 10 dimensions of space, so they're definitely spatial. The reason the theory has all those dimensions is because the premise is that fundamental particles are vibrating strings, and for that to work (when you go and do the math), they have to vibrate in 10 dimensions of space, hence the 10 dimensions.
Unless you've seriously studied this stuff for years and are an absolute genius, I don't think you'll find major revisions to it based off a few minutes of thought.
The reason they're confined to these three dimensions is because the endpoint of every string is some other n-dimensional brane.
See, it's kinda a misnomer to call them "branes" and "strings", really branes are just strings but higher-dimensional ones, and strings are just 1-dimensional branes.
Baryonic matter is all composed of strings that have their endpoints on our brane. Gravity is the exception - I think, iirc, it's because gravity is described by a tensor field rather than a vector field, or something like that - this has something to do with the formulation of Superstring theory that means that gravity would have to be a string with another 1d string attached rather than our 3d brane, meaning gravity is free to bleed into higher dimensional space, thus it wouldn't follow the inverse-square law until it "saturates" the higher dimensions, so you could see it bleed into the higher dimensions over short distances.
I don't know this for sure, but I'm guessing that might actually have something to do with why they thought they might make black holes in the LHC - but the main thing is it'd explain why gravity is so much weaker than the other fundamental forces.
But the theory is very much built on the necessary condition that the strings vibrate through the full 10 dimensions of space, so they're definitely spatial. The reason the theory has all those dimensions is because the premise is that fundamental particles are vibrating strings, and for that to work (when you go and do the math), they have to vibrate in 10 dimensions of space, hence the 10 dimensions.