| MadSci Network: Physics |
" Brane" is a generic geometrical term which is used to describe shapes in superstring theory. A string is a 1-dimensional object (even if it's not straight), so a string is called a 1-brane. A 2-dimensional membrane (like a thin film) is a 2- brane. Our entire 3-dimensional universe is a 3-brane (moving through time).
In multi-dimensional string theory, you can talk about 5-branes embedded in a 10-D superspace, etc. The number tells you how many spatial dimensions the object has.
Sometimes they're also called D-branes.
As for "unsharp", that's an obscure mathematical term which relates to quantum mechanics, not space or gravity. Perhaps there are some theories of quantum gravity which toss around this term, but I wouldn't bet that any of them are correct!
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