Angelo Esposito

Dark matter is invisible, but you can catch it on the rebound. Hydrogen embedded in a carbon film acts like a billiard ball: when a dark matter particle hits it, the proton flies out. That ejection is the signal you're looking for.

Dark matter has eluded direct observation so far, even though its gravity holds galaxies together. One hypothesis: it’s made of axions — ultra-light particles predicted by theory.