So if we see the positrons coming from a particular direction, it means astrophysics like a pulsar (a type of neutron star) is responsible for the signal, not dark matter.' Professor Ting told the BBC: 'Dark matter is supposed to be everywhere. 'That is the key signature for the dark matter annihilation in our galaxy's halo.'Īnother key piece of evidence will be whether positrons appear to be flowing in just one direction, or coming in from all around. 'The smoking gun signature in the positron to electron ratio is a rise and then a dramatic fall,' said Professor Turner. The forthcoming paper will report how many of each it found and what their energies were, he said.īy calculating the ratio of electrons to positrons and analysing the behaviour of any excess across the energy spectrum, researchers hope to edge their way towards an understanding of dark matter.
The $2billion, seven-ton machine, which was installed on the ISS in May 2011, is able to detect the positrons and electrons left behind by dark matter collisions in the Milky Way.Īccording to Professor Ting, the spectrometer in its first 18 months witnessed 25billion particle events, including eight billion fast-moving electrons and positrons. These exotic particles are believed to be their own antimatter particles so, if two collided, they would be destroyed to release an electron and its antimatter equivalent, a positron. Researchers don't yet know what dark matter is made of, but there are some theories which suggest it is composed of what physicists have dubbed weakly interacting massive particles (WIMPs for short). This data is then sent from the ISS to the ground where researchers around the globe have compiled and analysed it. Using sophisticated filtration and compression techniques, the advanced 600 computer processors located on the AMS are able to reduce the amount of data down by a factor of 3,000. That's equivalent to filling a 1Gb USB memory stick every second. The instrument, the largest and most advanced magnetic spectrometer in space, has been collecting measuring data at a rate of 7 Gigabits per second, 24 hours a day. Orbiting the Earth at an altitude of 200 nautical miles, the AMS has been collecting information from cosmic sources emanating from stars and galaxies millions of light years beyond the Milky Way. The Alpha Magnetic Spectrometer is a particle physics experiment which has for the past 18 months been bolted to the outside of the International Space Station.