Am 25.07.2013 19:24, schrieb Nekar Xenos:
> Now for the part that I don't understand at all:
>
> I have heard it mentioned in scientific news that scientists have found
> the fourth dimension and measured it.
> How can you measure a dimension? I don't understand that. If the 4th
> dimension has a "thickness", what then is the thickness of the 3rd
> dimension. It makes absolutely no sense to me at all.

Those news actually make no sense for yet another reason: Scientists 
around the world should know better than to call a newly discovered 
dimension the "4th dimension", as the term is already firmly associated 
with time.

But yes, there is some sense to measuring a dimension: Imagine the 
universe was made up of only one spacetime dimension, and one additional 
dimension curled up in a small loop; the universe would then have the 
shape of a cylinder surface stretching into infinity(*) along the 
spacetime dimension. But the other dimension would be finite, and could 
probably be measured.

(*Alternatively, spacetime might also be finite, but on a much larger 
scale, in which case we'd get a torus surface.)

String theory postulates that there are indeed - AFAIR - about half a 
dozen extra dimensions, and it is suggested that they may indeed all be 
curled up in this manner, with sizes roughly on the scale of sub-atomic 
particles.

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