51¶¯Âþ

51¶¯Âþs at Tokyo University have drawn up plans for a million-tonne water
tank to see if protons decay over time. If they do, it would show that the
Universe must have a finite lifetime. Many physicists believe that protons have
a half-life some 20 times the age of the Universe. The proposed £225
million device—a cubic tank 100 metres across lined with light
detectors—would pick up faint flashes as protons in the water decay.
Dubbed Hyper-Kamiokande, it would be 20 times the size of Japan’s
Super-Kamiokande detector, which in 1998 showed that neutrinos have mass.