*begin narrator voice-over* A mile-and-a-half beneath the frozen surfaces of the South Pole, the coldest, windiest, driest place on earth, something is watching. Far removed from the vibrations, clutter and noise caused by the world we live in, a gigantic piece of machinery is waiting. There, one square kilometer of the most advanced detection technology known to man is keeping an eye out for hints at the origins of the universe. *end narrator voice-over*
The name of the experiment is IceCube and it is one hell of an ambitious project being undertaken by the University of Wisconsin. About 85 strings each holding 60 spherical detectors are being lowered into the ice. Each of these detectors – or Digital Optical Modules (DOMs for short) – capture the tiny flashes of light that occur when a neutrino interacts with molecules of water in the ice. With so many different sensors working together, it is possible to track the flight path of a neutrino, which in turn lets scientists determine their origin, direction, energy and type.
So why aren’t they just building this in someone’s chest freezer, you ask? Simple enough. Neutrinos are tough cats to catch.
Though there are literally trillions of neutrinos flying through your very body every single second. I’m not exaggerating. But because they are so incredibly small and have no electrical charge, they barely ever interact with the visible world. And when it does, it isn’t likely to produce a visible effect.
However, every now and then when a neutrino hits an atom in ice, the collision creates a muon, which is another type of tiny particle, except this one radiates blue light. Because the ice where the detector is being built is so pure and transparent, the light can travel for 100 meters or more. And since there is so much ice, the probability of catching a neutrino interaction goes up.
The question may arise as to why we care about these tiny neutrino things if they don’t even impact our daily lives. Well, the answer lies in pure curiosity. Neutrinos are created by the decay of radioactive elements, which in turn are created in some of the most incredible settings in the universe. Exploding stars, super dense neutron stars and even the beginning of the universe itself are all big sources of neutrinos. Picking them out and learning about how they are made and where they come from will help us understand how these astronomical phenomena work, and maybe even where all this crap in the universe came from.
Check out this cool video from the National Science Foundation about the project.