Dark Matter May Be Completely Invisible, Concludes World's Most Sensitive Search

Dark matter is the most elusive substance ever detected in the Universe, and even at that, it’s only been detected indirectly. We know it interacts gravitationally, but it’s so sparse and diffuse that Earth-based experiments don’t stand a chance at seeing that interaction. Instead, if we want to see this new form of matter directly, we have to hope that there’s an additional interaction: a way for dark matter to scatter off of normal matter, and produce a recoil due to a collision. In an announcement earlier today, the LUX Collaboration — running the Large Underground Xenon experiment — performed the longest, deepest, most sensitive search for dark matter ever, using 370 kilograms of liquid xenon with the detector running for a total of 20 months. The final result? Not a single dark matter collision was observed.