Dark matter is believed to outnumber regular matter by a ratio of 5:1, yet it has remained undetectable despite decades of research. A new experiment, proposed by physicists at the University of Southampton, aims to tackle this cosmic mystery by sending a satellite into space equipped with a levitating piece of graphite and a laser-based detection system.
For years, researchers have designed various detection methods, including deep underground liquid xenon tanks that attempt to capture elusive weakly-interacting massive particles (WIMPs). However, no experiment has yielded conclusive results.
The University of Southampton team is shifting the search to space, proposing a compact CubeSat experiment measuring just 10 x 10 x 7 cm and weighing 1.5 kg.
Inside this satellite, a 1-gram sheet of graphite is magnetically levitated. A laser beam shines towards a photon detector, with the floating graphite partially blocking the light. If waves of dark matter pass through the satellite, they could subtly disturb the levitating graphite, altering the light reaching the detector.
Physicist Tim Fuchs describes the concept: “You could see this as a ‘dark matter wind’ pushing our graphite like a sail, with periodic variations along the orbit.”
Because Earth moves through the galaxy’s predicted dark matter halo, the satellite’s traps—aligned in three different directions—could measure varying levels of dark matter flux, providing crucial data on its properties.
Traditional ground-based experiments, such as LUX and XENON1T, rely on detecting rare interactions between dark matter and xenon atoms, deep underground where outside interference is minimized. However, if dark matter interacts more frequently than expected, it could be absorbed by Earth’s atmosphere or geological structures, rendering these detectors ineffective.
“If there is sufficient density of dark matter particles that have a sufficiently high [interaction rate], they would be shielded from Earth-based detection by either the atmosphere or any other type of overhead burden,” Fuchs explains.
By placing the experiment in orbit, researchers eliminate this interference, potentially increasing the chances of a successful detection.
The satellite is expected to launch next year and will conduct experiments for two years. While there’s no guarantee that this mission will confirm dark matter’s existence, expanding the search to new environments improves the chances of finally unraveling one of the universe’s greatest mysteries.
