Even if experimenters bounce the beams to and fro to increase the effective length of an interferometer's arms to more than 100 kilometres, the expected difference in length between the two beams' paths still amounts to less than a hundred-millionth of the diameter of a hydrogen atom.

ECONOMIST: Fundamental physics

Laser interferometers are looking for disturbances in their experimental set-ups that are equivalent to mere fractions of the diameter of a proton, one of the particles that make up the nucleus of an atom.

BBC: Lab tuned to gravity's 'ripples'