...like something so basic as the size of a proton. Sure, they can build the LHC and look for the Higgs boson and spend 30+ years developing String Theory without yet even devising a single experiment to test it, so then how come it is so difficult to find out the size of a proton, one of the three most elemental subatomic particles?
C & E News is reporting on a new experiment that concluded the proton is 0.84184 femtometers across, down 4% from the currently agreed upon value of 0.8768 fm. Such a change would apparently cascade causing wide swaths of physics to be re-examined.
As has been pointed out elsewhere, Emil Fischer had a 1:16 chance of correctly identify the stereoisomers of the sugars and he nailed it. Ben Franklin had a 1:1 chance of correctly identify the direction of current flow and got it wrong. When it counts, go with a chemist.