Near the French/Italian border in a tunnel between Bardonecchia and Modane, sits the Modane Underground Laboratory. It is Europe’s deepest lab – you can take a visual tour here. It’s home to a physics experiment that is stretching the patience of many of the world’s major scientists, as it could be years before any results are seen, if at all.
The experiment is taking place underground, in Europe’s deepest laboratory, because it needs to occur in an atmosphere that is protected from cosmic rays that are found on the Earth’s surface. The SuperNEMO machine isn’t very big considering its important role – it’s just six metres long, four metres high and three metres wide.
The SuperNEMO is in a room that is kept extremely clean because the dirt and dust around us contains a tiny amount of naturally occurring radioactivity and if this came into contact with the SuperNEMO, it would contaminate the experiment. That’s because the machine is keeping track of 7kg of the element selenium to see how radioactive it might become. It is hoping to find a very rare form of radioactivity called double-beta decay. This radioactivity has been predicted but never observed.
The technical issues behind finding double-beta decay in selenium are explained here, but if it does happen, it will be one of the most exciting results to occur in the field of physics. If the decay occurs in the way that is hoped, then the particles inside the neutrons inside the selenium would get an extra jolt of energy as they come into contact with each other. This jolt would make us rethink how the planet came into being and how the Big Bang happened. This wouldn’t just be huge; it would literally be the answer to the meaning of life.