Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2003 August 3
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

Ice Fishing for Cosmic Neutrinos
Credit: Robert Morse (U. Wisconsin) The Amanda II Collaboration

Explanation: Scientists are melting holes in the bottom of the world. In fact, several holes have been melted near the South Pole, and they are now being used as astronomical observatories. Astronomers with the Antarctic Muon and Neutrino Detector Array (AMANDA) lower into each vertical lake a string knotted with basketball-sized light detectors. The water in each hole soon refreezes. The detectors are sensitive to blue light emitted in the surrounding clear ice. Such light is expected from ice collisions with high-energy neutrinos emitted by objects or explosions out in the universe. The above picture was taken looking down into the deep abyss. Instruments were lowered down past 2000 meters. Analyses of data from the AMANDA II detectors have recently been used to create the first map of the high-energy neutrino sky.

Tomorrow's picture: Virgo Central

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