According to M-string theory there are seven extra dimensions that we have and don't know what to do with. Perhaps we use them after all. In dimension X we would all be a millimeter away all the time. Speculate away, but we will require laboratory data at some point.
Well, M-string theory is one of many other string-theory conceptions, RightWhale. So i wonder why the respective theorists are running around describing their work as a "theory" in the first place. Wouldn't "hypothesis" be a more apt, more descriptive word?
Don't get me wrong. I don't "rule out string theory in principle." And it seems very clear to me that the theorists are right to propose additional dimensions beyond the 3+1D block in order to account for empirically observable phenomena. But there are also other string theory hypotheses that do not require the compactification of the newly imagined dimensions. Plus I've seen different proposals that stipulate different numbers of dimensions. Eleven seems to be the currently fashionable concept; but maybe you only need some X more than four of 'em.
To me (a non-expert), it looks like the jury's still out on string theory. Though I definitely wish the researchers well, and hope they will come up with the telling insights we need to advance the physical sciences.
Which of course means that I entirely agree with your statement, "Speculate away, but we will require laboratory data at some point."
Thanks for writing, RW!