December 24, 2010

Antarctic IceCube Observatory Completed

The Antarctic IceCube observatory, an amazing underground observatory for viewing subatomic particles has finally been completed after ten years of work in a cube of ice under the South Pole.

Building the IceCube, the world's largest observatory, has been a punishing decade-long process in the Antarctic tundra. But now completed, it will allow scientists to study space particles in the search for dark matter, invisible material that makes up most of the Universe's mass.

The observatory, located more 4,500 feet underground near the US Amundsen-Scott South Pole Station, cost more than $270 million, according to the US National Science Foundation (NSF).

The cube is a network of 5,160 optical sensors, each about the size of a basketball, which have been suspended on cables in 86 holes bore down into the ice with a specially-made hot-water drill.

NSF said the final sensor was installed in the cube, which is about 3,280 long in each direction, on December 18. Once the sensors are in place they will be forever suspended in the permafrost as the drill holes fill with water and then freeze.

The sensors will allow scientists to study neutrinos -- subatomic particles that travel at close to the speed of light but are so small they can pass through solid matter without colliding with molecules.

They believe neutrinos were first created during the Big Bang more than 4 billion years ago and are still generated by nuclear reactions in suns and when a dying star explodes, creating a supernova.

Trillions of neutrinos pass through the entire planet all the time without leaving a trace, but the IceCube seeks out the blue light emitted when an occasional neutrino crashes into an atom in the ice.

"Antarctic polar ice has turned out to be an ideal medium for detecting neutrinos," NSF said in a statement announcing the project's completion. "It is exceptionally pure, transparent and free of radioactivity."

Scientists are calling the IceCube a milestone for international research and say the study of neutrinos will help them understand the origins of the Universe.

"From its vantage point at the end of the world, IceCube provides an innovative means to investigate the properties of fundamental particles that originate in some of the most spectacular phenomena in the Universe," said the NSF.

Most of the funding for the IceCube came from the NSF, with contributions from Germany, Sweden and Belgium. Researchers from Canada, Japan, New Zealand, Switzerland, Britain and Barbados also worked on the project.

The project is run by the University of Wisconsin at Madison.


Image 1: Sensor descends down a hole in the ice as part of the final season of IceCube. Icecube is among the most ambitious scientific construction projects ever attempted. Credit: NSF/B. Gudbjartsson

Image 2: Matthias Danninger assists in deployment of a Digital Optical Module. Credit: NSF/F. Descamps


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