Explanation:

Researchers in Germany have started collecting data with a $71 million machine designed to help determine the mass of the universe’s lightest particle.

Physicists, engineers and technicians at the Karlsruhe Institute of Technology hope the 200-metric tonne device will narrow down or even pinpoint the actual mass of neutrinos.

Those are sometimes called “ghost particles” because they’re so difficult to detect. Scientists with the Karlsruhe Tritium Neutrino experiment, or KATRIN, said they’ll be taking measurements “well into the next decade” and hope to produce “high-impact results.”