Gravity Normal At Small Scales.

[ohwilleke]

A study of gravity at the 6-20 micrometer scale has found it to behave normally and experimentally constrained the scale of any small scale deviation from the Newtonian expectation.

http://www.arxiv.org/abs/hep-ph/0508204

Hat tip to Motl for noting the paper.

[Chronos]

Isn't it amazing how difficult it is to test gravity at not-so-extreme limits? I've always thought so. 6-20 micrometers is enormous compared to most scales at which we test fundamental interactions. Kinda reminds me of the Planck mass.

[Haelfix]

If you want to learn more about these sorts of experiments *and they are really cool IMO* check out this page

http://www.npl.washington.edu/eotwash/

and for instance a review article on various ways of doing this experiment

http://www.npl.washington.edu/eotwash/pdf/review.pdf

Basically all these experiments are like the famous Cavendish experiment in one shape or another. The more modern versions now use casimir forces to measure the deviation.