Your phone's GPS can help find your way in the dark, but GPS could also help find dark matter too. Scientists are using location satellites to investigate whether the mysterious matter making up 80 percent of our universe is found in cracks in space that warp time.
Dark matter can't be seen using conventional telescopes and it doesn't interact with atom-based matter, but scientists know it's there because the stuff we can see only appears to make up 20 percent of our universe. One theory suggests that dark matter could come from kinks or cracks in the universe's quantum fields, kinks that could disturb such fundamental properties as the mass of an electron and have an effect on the way we measure time.
Scientists Andrei Derevianko at the University of Nevada, Reno, and Maxim Pospelov at the Perimeter Institute in Waterloo, Ontario, Canada propose their theory in the Nature Physics journal, as reported by New Scientist. They suggest that dark matter could have a disruptive affect on atomic clocks, and that by looking at existing networks of atomic clocks it might be possible to spot pockets of dark matter by their distinctive signature.
And what better network of atomic clocks to investigate the theory than the network of global positioning system (GPS) satellites already thronging the skies above the earth. GPS satellites are poised above the earth telling your smartphone or satnav where they are, but as the earth is also swooshing along at 300 kilometres per second, those satellites are covering a lot of space too. The theory is that if the earth passes through a cosmic kink, the effects will ripple across the satellite network, each clock in turn desynchronising from the rest of the network.
Derevianko is combing through 15 years' worth of data from GPS satellites to look for such timey-wimey effects. And if the theory turns out to be correct, the search could be expanded to an even bigger network of cosmic clocks: dead stars. The pulsars left after a star goes supernova give off electromagnetic radiation that can be used to measure time even more accurately than an atomic clock, and so they could be used to search for cosmic kinks.
The hunt for dark matter is on using various technologies from detectors hidden deep inside gold mines to shield them from cosmic radiation, to the and the planned in Japan. Possible theories have suggested that dark matter could be made up of "massive astrophysical compact halo objects" -- MACHOs -- or "weakly interacting massive particles" -- WIMPs.