No longer the domain of hikers or the map-friendly element on your smartphone, GPS is now being used to find dark matter.
Two researchers in North America have proposed using GPS satellites to search for the elusive, infamous dark matter that has eluded space explorers for decades.
It’s a strange situation to describe, given that nobody knows what on Earth, or rather off Earth, dark matter is. US space agency NASA doesn’t even pretend to fully understand what it is, claiming to be much more certain of what it’s not.
“First, it is dark, meaning that it is not in the form of stars and planets that we see. Second, it is not in the form of dark clouds of normal matter, matter made up of particles called baryons. Third, dark matter is not antimatter, because we do not see the unique gamma rays that are produced when antimatter annihilates with matter.
“Finally, we can rule out large galaxy-sized black holes on the basis of how many gravitational lenses we see. The most common view is that dark matter is not baryonic at all, but that it is made up of other, more exotic particles, such as axions or WIMPS (weakly interacting massive particles).”
The duo behind this latest report – Andrei Derevianko of the University of Nevada, and Maxim Pospelov of the University of Victoria – are suggesting the use of GPS satellites can search for topographical features in dark matter, which they believe is possible.
Andrei Derevianko, professor of physics at the University of Nevada. Photo via University of Nevada
“Our research pursues the idea that dark matter may be organised as a large gas-like collection of topological defects, or energy cracks,” Derevianko said.
“We propose to detect the defects, the dark matter, as they sweep through us with a network of sensitive atomic clocks. The idea is, where the clocks go out of synchronisation, we would know that dark matter, the topological defect, has passed by. In fact, we envision using the GPS constellation as the largest human-built dark-matter detector.”
Dark matter detection ideas
As reported by Phys.org, Derevianko is collaborating on analysing GPS data with Geoff Blewitt, director of the Nevada Geodetic Laboratory, which maintains the world’s largest GPS data processing site. The two are starting to test the dark matter detection ideas by analysing clock data from the 30 GPS satellites, which use atomic clocks for everyday navigation.
Blewitt, also a physicist, explained how an array of atomic clocks could possibly detect dark matter.
“We know the dark matter must be there, for example, because it is seen to bend light around galaxies, but we have no evidence as to what it might be made of,” he said.
“If the dark matter were not there, the normal matter that we know about would not be sufficient to bend the light as much as it does. That’s just one of the ways scientists know there is a massive amount of dark matter somewhere out there in the galaxy. One possibility is that the dark matter in this gas might not be made out of particles like normal matter, but of macroscopic imperfections in the fabric of space-time.
“The Earth sweeps through this gas as it orbits the galaxy. So to us, the gas would appear to be like a galactic wind of dark matter blowing through the Earth system and its satellites. As the dark matter blows by, it would occasionally cause clocks of the GPS system to go out of sync with a tell-tale pattern over a period of about three minutes. If the dark matter causes the clocks to go out of sync by more than a billionth of a second we should easily be able to detect such events.”
Distant universe image via Shutterstock