News on quantum gravity, strings and other interesting stuff in physics.
Novidades em gravitação quântica, cordas e outras coisas interessantes em física.
17 November 2006
No Extra Dimensions Found (Yet)
The Washington group reports new data on possible modifications of the inverse square law for gravity. Using a torsion balance they tested Newton's gravity law between 9.53mm and 55μm and found no deviation. With the present knowledge for dark energy density, which gives a dark energy length scale of 56μm, the size of extra dimensions must be smaller than 44μm.