According to physicists, only around five percent of what makes up the universe can presently be detected. The existence of dark matter is inferred from the behavior of faraway galaxies, which move in ways that can only be explained by a gravitational pull caused by more mass than can be seen. They estimate dark matter represents around 20 percent of the universe, with the other 75 percent made up of dark energy, a repulsive force that is causing the universe to expand at an ever-quickening pace.
At the heart of Abancens’ team’s detector, which is called a scintillating bolometer and resembles a prop from The Golden Compass, is a crystal so pure it can conduct the energy ostensibly generated when a particle of dark matter strikes the nucleus of one of its atoms.
To prevent interference by cosmic rays, the bolometer is sheathed in lead and kept underground, under half a mile of rock. It’s also frozen to near-absolute zero, the temperature at which all motion stops. At the edge of absolute zero, it’s possible to measure expected changes of a few millionths of a degree Fahrenheit.