22 December 2010
It’s called ICE CUBE and it’s at the bottom of the World. Actually it’s IN the bottom of the World, and without doubt it’s the strangest telescope on Earth.
Ice Cube is a neutrino observatory. It’s made up of hundreds of detectors embedded in the ice 1 km beneath the South Pole. My name is on one of those detectors, and it something I am very proud of!
The NSF announced this week that the final detectors have been installed and Ice Cube is officially complete. I visited last January as they were well underway.
Neutrinos are the smallest thing you cannot imagine. They are the tiniest wisp of nothing we humans can contemplate. They are so small that billions are passing through your eyeball right now.
Not to worry, they will likely hit nothing. Most neutrinos pass through the entire Earth and hit nothing. They could pass through a light year thick slab of Lead and still most would not hit anything!
Do you begin to understand what I mean when I say small?
Neutrinos have no charge like electrons and protons, and they do not interact with matter. The only time we can observe one is when one just happens to crash into the nucleus of an atom.
When that happens in ice, a particle called a muon is ejected at nearly the speed of light. The speed of light is slower in ice than in a vacuum, and if a particle is going faster than the light speed in ice, it produces a flash of blue light called Cherenkov radiation. (Yes, nothing can go faster than the speed of light in a vacuum, but particles can go faster than the speed of light in ice!)
By tracking the direction of the flashes of Cherenkov light researchers can calculate backwards where the neutrino came from. They can also measure the intensity.
So where are you going to find a 1km thick cube of clear pristine ice with the facilities to house scientists and do research? The answer is easy, Amundsen Scott Station at the South Pole.
Using very hot water, produced from melted ice, the ice cube folks have drilled a bunch of deep holes in the ice. Then they lowered a string with special detectors on them into the ice. The detectors freeze into the ice and can detect flashes of light when a neutrino hits an atom. There are 80 holes with a string of 60 detectors called DOMS in each hole.
That’s around 4800 detectors! When I was at the Pole, I got to sign one. That detector with my name on it is now in the ice and part of Ice Cube.
Oh the things that make a science geek smile!
Why are neutrinos so important? To answer that properly requires an expert to write a good book. Fortunately someone did and the book is a really interesting read.
Frank Close of Oxford wrote NEUTRINO. You might think a book about a particle would be boring. It’s not! Frank Close tells an intriguing story of how science finally spotted one!
Neutrinos are made in stars, and they were made in the big bang when the universe was a fraction of a second old. They are kind of like an astronomical X-ray. They allow astronomers to see into stars and through the gas and dust of the universe.
Below is a video clip I shot that gives a feel of the place.
Neutrinos are the subject of intense research right now and Ice Cube may very well make some amazing discoveries that begin to answer some of the most weighty questions in science. Think about it. 96% of the universe is made up of dark matter and dark energy.
It’s called dark because we cannot see it and have no idea what it is! Only 4% of the universe is visible to us. Neutrinos may very well help scientists to figure out what dark energy and dark matter really are. It’s a really big deal and you will understand how big, if you read the book.
You will also know more about neutrinos than 99.9% of the people on Earth!
You can find out more about Ice Cube here.