GPS Satellites Might Be Able to Detect Dark Matter

Image from Science Illustrated

Dark matter has historically been one of the most elusive substances in the universe, but, according to new research, the key to finding it might be right under our noses. A new study from an international research team shows that we may be able to detect dark matter using GPS satellites, as a result of their usage of atomic clocks.

Dark matter is a hypothetical type of matter that doesn't interact with any kind of electromagnetic radiation, and therefore is virtually impossible to observe. Physicists have long theorized its existence in order to account for gravitational effects on normal matter and for the overall structure of the universe. The search for dark matter is one of the most prominent objectives in modern particle physics, as it is thought to make up 85% of the matter in the known universe. Most in the scientific community essentially take for granted that dark matter exists, but continue to search for proof of its existence and answers as to what type of particle composes it.

Co-author Andrei Derevianko, of the University of Nevada, states the dark matter problem as follows: "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. 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."

The new study proposes that dark matter consists not of particle-like matter, which is the current prevailing theory, but of macroscopic imperfections, or "cracks," in the fabric of spacetime. If this conception of dark matter is correct, then we should theoretically be able to detect it using an atomic clock system. Atomic clocks, like the ones used in GPS satellites, operate according to atomic physics, rather than nuclear physics as normal clocks do. In other words, while the pendulum in a normal clock oscillates according to all the macroscopic, conventional rules of physics, atomic clocks literally oscillate according to the frequency of an atom. Atomic clocks are so accurate precisely because they work on such a fundamental level, which makes them ideal candidates to measure anomalies in spacetime, as little else could interfere with the clock's accuracy.

From the paper: "A transient-in-time change of fundamental constants can be induced by dark-matter objects... During the encounter with an extended dark-matter object, as it sweeps through the network, initially synchronized clocks will become desynchronized."

A diagram explaining the desynchronization of two atomic clocks:

[Credit: Andrei Derevianko]

"We envision using the GPS constellation as the largest human-built dark-matter detector," said Derevianko. 

Collaborator Geoff Blewitt, director of the Nevada Geodetic Laboratory, explained the mechanism of the dark matter's interference as follows: "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 3 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." 

The researchers have only just begun to test and analyze the actual data from the satellites, but their theories have been extremely well-received in the scientific community. The above paper was published in the well-regarded and peer-reviewed journal, Nature Physics, and their presentations of the hypothesis at conferences earlier this year were met with an onslaught of support.