Using lasers and space-time-separated atomic clocks, researchers from the University of Queensland (UQ) have yielded previously undiscovered results about the nature of dark matter, the enigmatic substance believed to comprise most of the matter in the cosmos.
Previous efforts have occasionally detected the effects of this mysterious nonluminous material, although the latest effort successfully detected forms of dark matter through their behavior as waves, offering scientists a new approach in the search for the substance’s enigmatic nature.
How Lasers and Space/Time-Separated Clocks Shed “Light” on Dark Matter
According to the generally accepted Lambda-CDM model of cosmology, the universe is 5% ordinary matter, 26.8% dark matter, and 68.2% an equally enigmatic and elusive form of energy known as “dark energy.” If correct, this means that close to 95% of the universe’s mass-energy content is comprised of nonluminous material that cannot be directly observed by astronomers.
Past studies by The University of Hong Kong have proposed dark matter was made up of ultralight particles known as axions instead of the more commonly hypothesized weakly interacting massive particles (WIMPS). A number of innovative ideas have been proposed by astronomers to aid in searching for dark matter, which include actively searching for axions around the magnetic fields of stars, leveraging the light from pulsars, or even looking for clues to dark matter in billion-year-old geological formations.
Unfortunately, while such past research has offered tantalizing clues, the authors of this latest study note that none have been able to measure the elusive substance directly.
“Despite many theories and experiments, scientists are yet to find dark matter, which we think of as the ‘glue’ of the galaxy holding everything together,” explained UQ PhD student Ashlee Caddell, who co-led a new study with Germany’s metrology institute Physikalisch-Technische Bundesanstalt (PTB), in a statement.
Caddell added her team approached the problem in a way that had not been tried before. Specifically, rather than employing typical tests looking for the gravitational effects of dark matter, the researcher says this new effort focused on data “from a network of ultra-stable lasers connected by fiber optic cables, as well as from two atomic clocks aboard GPS satellites.”
Because dark matter is known to behave like a wave due to its extremely low mass, the team employed a series of space/time-separated atomic clocks and lasers. If they detected something that looked like a disparity in the two clocks, that finding would hint at the presence of a new form of dark matter.
“Dark matter, in this case, acts like a wave because its mass is very, very low,” Caddell explained. “We use the (space/time) separated (atomic) clocks to try to measure changes in the wave, which would look like clocks displaying different times or ticking at different rates.”
“This effect gets stronger if the clocks are further apart,” Caddell added, highlighting the benefit of the two satellite-based clocks.
Analysis Reveals “Subtle Effects”
After several tests, the team analyzed the data they collected to determine whether the effects of dark matter were present. According to Caddell, the team’s innovative search method using lasers and space/time-separated atomic clocks was successful.
“By comparing precision measurements across vast distances, we identified the subtle effects of oscillating dark matter fields that would otherwise cancel themselves out in conventional setups,” the scientists explained.
The study’s co-author, UQ physicist Dr. Benjamin Roberts, noted the significance of the findings compared to previous efforts due to their ability to detect the effects of dark matter on all atoms. The researcher also highlighted the benefits of the unprecedented findings to other researchers in the field who are looking for innovative new methods to further unravel the mysterious nature of dark matter.
“Excitingly, we were able to search for signals from dark matter models that interact universally with all atoms, something that has eluded traditional experiments,” said Roberts. “Scientists will now be able to investigate a broader range of dark matter scenarios and perhaps answer some fundamental questions about the fabric of the universe.”
“This work also highlights the power of international collaboration and cutting-edge technology, using PTB’s state-of-the-art atomic clocks and UQ’s expertise in combining precision measurements and fundamental physics,” Roberts concluded.
The study “Ultralight Dark Matter Search with Space-Time Separated Atomic Clocks and Cavities” was published in Physical Review Letters.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.