> ... and at distances longer than [100 microns], it really follows the ISL
But at cosmic distances, there's also evidence that gravity doesn't follow ISL, right?
Are there any implications of this work for hypothesized dark matter and dark energy?
Gravity not following the ISL at large scales would indeed be a possible explanation for this. However, most alternative theories of gravity clash with other observations, such as the motion of binary pulsars or gravitational waves, whereas (unmodified) General Relativity is in excellent agreement. This is one of the reasons why the existence of dark matter is considered to be a much better explanation for the deviation of the rotation curves.
But I know so little physics that the distinction between dark matter and extra terms in gravitation is unclear.
At distances longer than that, these measurements show that gravity acts, and in a way that roughly follows the inverse-square law. (at distances of ~100 microns it very-much follows the ISL, and at distances longer than that, it really follows the ISL).
The easy way to think about this result: we are on the cusp of showing that gravity acts over distances shorter than the width of a human hair. Only the finest human hairs are smaller in diameter.
For many years, my goal in life (see HN handle) was to push this limit below 10-microns. Turns out that is really hard to do :).