IceCube scientists fly home for the Winter
Massive Antarctica particle project hails neutrino success
An enormous project to build the world's largest neutrino telescope underneath the South Pole has completed its second Antarctic Summer of drilling work. The $272m IceCube detector will harness a cubic kilometre of solid ice to explore these mysterious sub-atomic particles.
Because of the unbearably bleak Antarctic winter, work is only viable for five months of the year. The team are pleased with the 2005/6 progress, though. Project leader Francis Halzen of the University of Wisconsin said: “It's good news all round. All the major challenges encountered by drilling a first hole last season have been solved.”
The drill uses simple hot water to cut down into the virgin ice, though the group assures us its tool is very sophisticated.
The plan is to sink strings of basketball-sized optical sensor modules one-and-a-half miles down into the crystal-clear ice. Very rarely a neutrino will smack into another particle in the ice and the light generated will be detected. This Antarctic summer the engineers positioned 480 of the eventual 4,200 below-ice modules.
The neutrinos IceCube hopes to detect will come from outside the Solar System. They will have passed all the way through the Earth from the Northern hemisphere. The idea is that the planet will act as a giant filter, removing the noisy cosmic background.
Neutrinos are like ghosts, say scientists, able to pass through Earth virtually anonymously. Billions go through our bodies every day without causing damage that more strongly-interacting, larger particle radiation can.
Their 'weakness' is also what makes them so hard to detect, and so mysterious. Even a property as seemingly basic as how much the little scamps weigh has proven elusive.
Until recently, the boffins didn't even know if they weighed anything.
This enigmatic nature stems from the fact that they are only involved in two of the universe's four fundamental forces: the weak nuclear force and gravity. Relative to the strong nuclear force and electromagnetism they're feeble and interactions are rare. That's why IceCube has to be so colossal.
It's the 'throw enough sh*t and some of it will stick' school of particle physics.
The fusion reactions of the Sun produce neutrinos in great numbers. The particular type the IceCube scientists are interested however in are formed by the most violent events in the universe; the big bang and supernovae. They want to know more about the distribution, and the origins of these highest-energy neutrinos.
The IceCube neutrino telescope is due for completion in 2011. Visit their site here.®