Seeing the dark: New MIT-led experiment could finally shed light on the mysteries of dark matter

Dark matter, believed by physicists to outweigh all the normal matter in the universe by more than five to one, is by definition invisible. But certain features associated with dark matter might be detectable, according to some of the many competing theories describing this elusive matter. Now scientists at MIT and elsewhere have developed a tool that could test some of these predictions and thus prove, or disprove, one of the leading theories.

The work is described in a paper in the journal Physical Review Letters co-authored by MIT physics professors Richard Milner and Peter Fisher and 19 other researchers.

“We’re looking for a massive photon,” Milner explains. That may seem like a contradiction in terms: Photons, or particles of light, are known to be massless. That’s why they travel at the speed of light — something that, according to Einstein’s theory of relativity, is impossible for anything that possesses mass.