March 1, 2001

5:02 AM

A small world in most dimensions:"University of Washington scientists using gravity measurements to hunt for evidence of dimensions in addition to those already known have found that those dimensions would have to occupy a space smaller than 0.2 millimeter."
posted by talos (8 comments total)

Interesting, but not really surprising. All they're really saying is that they didn't find anything unusual, so the effects they're looking for are really tiny, if present. Not really a surprise. If there's to be any chance of verifying the existence of the extra dimensions which string theory predicts, it's going to require either some incredbly sensitive equipment or an approach nobody's thought of yet.
posted by Nick Jordan at 5:30 AM on March 1, 2001

Agreed, but the point is that, apparently, the upper limit of "other dimension size" postulated by theory is well within the 0.2mm range tested. What is truly interesting is that experimental testing of string theory is now a possibility without needing to achieve exotically high energies. I remember 5 years ago suggesting to friends working on strings that what they were doing was not "real" physics but mathematical philosophical fiction. I now stand corrected...
posted by talos at 6:17 AM on March 1, 2001

If they were looking for other dimensions, they might want to consider that measuring them from THIS dimension, according to OUR equipment, might yield... inaccurate results? Isn't this like trying to measure a cube using TWO-dimensional measurements? On the other hand, I think it's cool that scientists are at least considering that there can be events in three dimensional reality that are affected by more than just what we 'see' - could this be the scientists' metaphysical doorway in? :-)
posted by thunder at 7:39 AM on March 1, 2001

I don't know that this has any great bearing on metaphysics, but I do agree with Talos that it's amazing that experimental testing of string theory is possible at all. I'm looking forward to the next instalment in the story...
posted by Nick Jordan at 8:28 AM on March 1, 2001

I think it's scary that there might be other dimensions with people in them searching for ours. What happens if, in their quest for knowledge, they step on this one by mistake?
posted by Neale at 2:20 PM on March 1, 2001

If string theory is correct and these other dimensions exist, they're almost certainly too small for anything (at least, anything intelligent) to be living in them.

Having said that, we mustn't forget that Arthur C. Clarke (I think) said that when a scientist says that something is possible, he is probably right, but when he says that something is impossible, he is probably wrong.

Nevertheless, I think that the chance is very small, so don't worry too much about it!
posted by Nick Jordan at 2:33 PM on March 1, 2001

Ehhh... just for comparison: How large are the dimensions we already know?
posted by palnatoke at 12:02 AM on March 2, 2001

I couldn't give you exact figures, but basically, the width of the universe. Bigger than you can possibly imagine, in other words.
posted by Nick Jordan at 12:37 AM on March 2, 2001