Thursday, 4 April 2013

Possible hint of dark matter from cosmos

Scientists say that cosmic ray detector on the International Space Station has found the footprint of something that could be dark matter. The mysterious substance that is believed to hold the cosmos together but has never been directly observed, .

The first results from the Alpha Magnetic Spectrometer, known by its acronym AMS, are almost as enigmatic as dark matter itself. They show evidence of new physics phenomena that could be the strange and unknown dark matter. It could be energy that originates from pulsars, scientists at the European particle physics laboratory near Geneva announced.

The results from the detector are significant, because dark matter is thought to make up about a quarter of all the matter in the universe. Unraveling the mystery of dark matter could help scientists better understand the composition of our universe and, more particularly, what holds galaxies together. Nobel-winning physicist Samuel Ting said at the European Organization for Nuclear Research that he expects a more conclusive answer within months about this "unexpected new phenomena."

The Alpha Magnetic Spectrometer is an advanced cosmic-ray detector designed to seek out signs of antimatter and elusive dark matter from its perch on the backbone-like main truss of the International Space Station. More than 200 scientists representing 16 countries and 56 institutions are part of the science team. The 7-ton detector, which was sent into space two years ago and has a 3-foot (0.91-meter) magnet ring at its core, is transmitting the data to CERN on the Swiss-French border. The instrument will search for antimatter and dark matter for the rest of the life of the space station and transmitting data to an international team of 600 scientists based in Geneva that is led by Ting.

The spectrometer consists of a huge, 3-foot wide magnet that bends the paths of cosmic particles and steers them into special detectors designed to measure particles' charge, energy and other properties. The complicated space experiment was 16 years in the making, but despite its lofty mission, the 7-ton AMS almost never flew.

The findings are based on seeing an excess of positrons, positively charged subatomic particles. Since the highly accurate AMS magnetic detector began studying cosmic ray particles in space, it has found about 400,000 positrons whose surging energies indicate they might have been created when particles of dark matter collided and destroyed each other. "It is this level of precision that will allow us to tell whether our current positron observation has a dark matter or pulsar origin," Ting said.

Other scientists praised the results and looked forward to more. "This is an 80-year-old detective story and we are getting close to the end," said University of Chicago physicist Michael Turner, one of the giants in the field of dark matter. "This is a tantalizing clue and further results from AMS could finish the story."

The Alpha Magnetic Spectrometer was first attached to the International Space Station on May 16, 2011. Three days later, the instrument was activated for the first time and has been performing science observations ever since. The instrument is managed by NASA's Johnson Space Center in Houston.

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