Cosmological observations suggest that about 85% of the universe’s mass is made up of matter that neither emits nor absorbs light. The existence of this mysterious component—dark matter—is inferred from its gravitational effects and is theorized to interact only very weakly with ordinary matter. The XENON detector, located deep underground in Italy’s Gran Sasso Laboratory, employs a large reservoir of ultrapure liquid xenon to search for the faint signals produced when a dark matter particle collides with a xenon atom. By suppressing background radiation and using highly sensitive sensors, the experiment strives to observe these extremely rare events. Although dark matter remains undetected, XENON continues to search while also shaping future searches.
