What is it? The world's largest neutrino telescope
Size: AMANDA is made of more than 700 sensors arranged in a cylinder about 1 kilometre tall and 200 metres across.
Location: 1400 metres under the ice near the Amundsen-Scott station at the South Pole.
What's it for? Mapping the neutrino sky. Neutrinos stream out from the most violent events and objects in the universe, such as gamma-ray bursters and active galaxies with supermassive black holes at their centres. Their feeble interaction with matter makes them ideal astronomical messengers. Unlike light or charged particles, they travel across the cosmos without being absorbed by dust or deflected by magnetic fields, giving an unhindered view of objects that might otherwise be hidden.
A tiny fraction of neutrinos crash into oxygen nuclei in the Antarctic ice, sending atomic wreckage flying. Most of this debris is absorbed, but some particles carry on for hundreds of kilometres, giving out a glow that travels through the clear Antarctic ice to AMANDA's sensors, which hang suspended on strings from the ice cap.
Because the AMANDA team is looking at the neutrino sky for the first time, there is a chance the researchers might spot something completely new to astronomy.
Why so big? Neutrino interactions are few and far between. Only 1 in a million neutrinos passing through AMANDA produces a signal. But the huge detection volume massively increases the odds of spotting neutrinos.
Who's working on it? About 120 physicists from six countries
Status: Catching neutrinos since 2000. So far the team haven't seen any evidence for neutrino sources in deep space.
Cost: $31 million to design and build the detectors, excluding the cost of transporting them to the South Pole.
Monster Offspring: Researchers have started building a bigger version of AMANDA at the South Pole. Known as IceCube, the detector will comprise 5000 sensors buried in a cubic kilometre of ice and should be complete in 2009. Before then, NASA will fly a balloon for 30 days over the South Pole equipped with a neutrino detector called ANITA. The detector will monitor 1 million cubic kilometres of ice, looking for telltale pulses of radio waves given off by neutrinos streaking through.