The hiding spots for the particles making up dark matter are narrowing, and the answer to this cosmic mystery could come within the next three or four years, scientists say. Dark matter is an elusive substance that is invisible and almost never detected, except by its gravitational pull. Yet astronomers say it likely makes up a quarter of the entire universe and dwarfs the amount of normal matter (galaxies, stars and planets) out there in space.

Just before Thanksgiving, particle physics discovery from the Large Hadron Collider in Switzerland cast doubt on a theory called supersymmetry, which predicts the existence of particles that are among the leading candidates for dark matter. That finding limited the types of supersymmetric particles that can exist, but didn’t take the supersymmetry explanation off the table completely. And supersymmetric particles are just one of a number of theorized particles that might account for dark matter. Searches for these and other undiscovered particles have been underway for decades, though none have been detected so far.