A new detector to home in on the mystery of dark matter is getting closer to deployment.
At the University of Southampton in the UK, physicists are testing an apparatus that involves levitating sheets of graphite in microgravity to look for tiny anomalies that could point to the nature of this elusive substance.
“Dark matter remains one of the fundamental questions scientists are still trying to answer – it dictates the structure of our Universe but is still undetectable,” says physicist Tim Fuchs of the University of Southampton.
“There are lots of theories as to what dark matter might be but no experiment on Earth has ever come close to detecting it.”
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When we look out into the wider Universe, there’s a big discrepancy between the amount of normal matter that we can see, and the amount of gravity. Simply put, there’s way too much gravity to be attributed solely to normal, or baryonic, matter, the stuff that makes up all the stars and planets and dust.
We can tell this by looking at things like the rotation of the outer parts of galaxies, which is way higher than it should be based on their mass, or the way space-time warps and bends around huge masses. We can tell, based on measurements of these phenomena, that dark matter outweighs normal matter by a ratio of about six to one.
But we don’t know what dark matter is. We can’t detect it directly. It doesn’t give off any light, or interact with the Universe that we can tell, other than its gravitational impact. We may never know what it is, but scientists are not going to let it go without exhausting every possible avenue of inquiry.
This is where the work of Fuchs and his team comes in, with an experiment set to launch into Earth orbit aboard a satellite called Jovian-1, from whence it will be jettisoned to orbit Earth for a planned two years.
“Our experiment is unlike anything attempted before: we’ll be levitating graphite between magnets which, in zero gravity, are incredibly sensitive to small forces,” Fuchs explains.
“If there is a sufficiently high density of dark matter, a dark ‘wind’ will softly push our levitated particles by an amount we can measure – detecting it for the first time ever.”
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Jovian-1 will be around the size of a shoebox, carrying several experiments designed by students at the University of Southampton, the University of Portsmouth, and Surrey University, all in the UK. The team plans to launch the satellite in early 2026, so we might be waiting a while to see results.
But those results, when they arrive, could tell us a lot more about dark matter, whether a detection is made or not.
“There are theories that say the dark matter interaction rate may actually be so high that it cannot penetrate our atmosphere or the mountains under which detectors have been built. This might explain why many of the major Earth experiments that have been built to detect dark matter have not revealed any conclusive signals,” Fuchs says.
“Our mission is the first of its kind to use this levitating technology in space – and we hope it will serve as a proof of principle that we can detect dark matter above Earth.”
