January’s column was about snowflakes; this is about an ice cube, but a huge one called – wait for it – IceCube. Each side is 1 kilometer, 1,000 meters, so the volume is one billion cubic meters, and it weighs a billion tons. Scientists wanted a massive block of clear ice to detect mysterious neutrinos coming from far away in the universe. These particles interact with matter so rarely that 99.9999% pass right through that block leaving no trace. But one in a million hits a quark, much smaller than a proton, creating a shower of new particles, which make flashes of light in the ice.