GPS satellites could provide clues for dark-matter detection

New Scientist : The network of GPS satellites is nearly 50 000 km in diameter, and each satellite is equipped with a very precise clock. Along with Earth and the rest of the solar system, the GPS network travels through the galaxy at nearly 300 km/s. Andrei Derevianko of the University of Nevada, Reno, and Maxim Pospelov of the Perimeter Institute in Waterloo, Ontario, Canada, argue that this combination of factors makes the network a potentially useful tool for detecting a version of dark matter that may not consist of particles. They propose that dark matter could instead take the form of bends or cracks in the quantum fields that fill the universe. As the solar system passes through one of those cracks, it is possible that the GPS network would detect a variation in the satellites’ clocks. The effect would appear as a wave that spreads across the network at the rate of the solar system’s movement. Derevianko is now examining 15 years’ worth of GPS data to look for such a signal. If his initial search is unsuccessful, he plans to use a network of ground-based atomic clocks currently being built in Europe, which will be even more sensitive than the satellites’ clocks.