
Scientists might have found a way to finally spot dark matter.
Dark matter makes up most of the universe and is integral to the solar systems and galaxies that surround us. But it is invisible, and scientists can only understand it by studying the way that it interacts with the matter we can actually see.
Now researchers believe that they might be able to see it through the traces that it leaves on the gravitational waves that are constantly travelling through space and which we can detect on Earth.
Astronomers have predicted how gravitational waves would look if they have come out of a black hole that moved through dark matter, instead of empty space. They then applied that model to real data from gravitational wave signals that have already been detected.
From the 27 clearest signals of gravitational waves, 27 of them appeared to have emerged in a vacuum. But one of them, known as GW190728, seems to have the imprint of dark matter in its signal.
Researchers stress that the technique does not allow them to detect dark matter in itself. But it could offer a way of spotting the traces of it, which could then be used to examine possible traces of it using other techniques.
“We know that dark matter is around us. It just has to be dense enough for us to see its effects,” said Josu Aurrekoetxea, from the MIT Department of Physics. “Black holes provide a mechanism to enhance this density, which we can now search for by analyzing the gravitational waves emitted when they merge.”
The work is reported in a new paper, ‘Scalar fields around black hole binaries in LIGO-Virgo-KAGRA’, published in the journal Physical Review Letters.