A team of researchers has proposed a novel way to search for dark matter: in the perturbations of spacetime itself. The team pored over data from the third observing run of the Laser Interferometer Gravitational Observatory, or LIGO, and published its findings earlier this month in Physical Review Letters.

Dark matter is an umbrella term for the matter whose presence is inferred through its gravitational interactions with ordinary matter but which is otherwise invisible. Dark matter accounts for about 27% of the mass-energy content of the universe, and while it accounts for a huge amount of everything, it has proven vexingly difficult to observe directly. As in, scientists haven’t yet done so. Instead, they’ve been relegating to witnessing its gravitational effects on other objects.

“Some theories suggest dark matter behaves more like a wave than a particle,” Alexandre Göttel, a physicist at Cardiff University and lead author of the study, told Phys.org. “These waves would cause tiny oscillations in normal matter, which can be detected by gravitational wave detectors.”

Gravitational wave detectors like LIGO use interferometry to sense the ripples of spacetime caused by the motion and interactions of massive objects like black holes and neutron stars. LIGO essentially measures the distance travelled by underground lasers; when gravitational waves shrink or stretch spacetime, scientists can see in data that the lasers travelled a very slightly longer-or-shorter distance than before, indicating a gravitational wave passed through.

The recent team looked at ultralight bosons, which are one of the hypothesized forms of dark matter (other forms include axions and dark photons). One unique feature of the dark matter the team was investigating is its weak interaction with both matter and light, similar to Weakly Interacting Massive Particles, or WIMPs, and could form cloud-like formations that would make it possible for it to show up in gravitational wave detector data.

“At an atomic level, you can imagine the dark matter field as fluctuating alongside the electromagnetic field,” Göttel said. “The dark matter field oscillations effectively modify the fundamental constants, i.e., the fine structure constant and electron mass, which govern electromagnetic interactions.”

Though the team has not directly detected dark matter, they set new limits on the strength of the interaction such matter would have with the LIGO components. The team’s new measurement improved that of previous work by a factor of 10,000 in the particular frequency range they were testing.

It may (read: will) be a long time before scientists directly detect dark matter for the first time, so it’s good that they’re looking everywhere they can.