Astronomers may have discovered a new way to detect dark matter particles using the Earth’s atmosphere itself.
Dark matter is made up of mysterious, invisible particles that are incredibly difficult to detect, “visible” only through the effect they have on the rest of the universe. This matter is thought to make up 85% of the universe and about a quarter of its mass.
A new study has suggested that the discovery of this elusive material could be made using ground-based radar systems.
Scientists generally only look for tiny dark matter particles, but it is possible that large-mass particles can be found, which may not reach traditional detectors on Earth.
“One of the reasons dark matter is so difficult to detect may be because the particles are so massive,” said John Beacom, a professor of physics and astronomy at Ohio State. “If the mass of dark matter is small, the particles are common, but if the mass is large, the particles are rare.”
The way this would happen is similar to how scientists track meteors, which both produce deposits of ionization, a form of radiation that leaves behind atoms that can conduct electricity known as free electrons.
Radars send electromagnetic energy into the atmosphere, which then bounces off the electrons. This then signals the presence of a meteor or dark matter.
This new practice could be used in conjunction with other ways to search for dark matter. ‘Current cosmology techniques are quite sensitive, but they don’t have a way to control their work,’ said Professor Beacom.
“This is a completely new technique, so if scientists aren’t sure what they’ve detected, a signal from cosmology could be checked in detail with radar.”
Scientists have only recently detected the dark matter that surrounded galaxies 12 billion years ago by observing how light travels through distant star clusters. Researchers use microwaves rather than visible light, showing how dark matter accumulated in the early universe.
However, while the theory suggests that dark matter should stick together and form clumps in the cosmos, there was far less than expected.
“Our discovery is still uncertain,” said Hironao Miyatake of the University of Nagoya, “but if true, it would suggest that the whole model is flawed as we go further back in time. This is exciting because if the result is persists after uncertainties have been reduced, could suggest an improvement in the model that could provide information on the nature of dark matter itself. “