Science Daily goes deep beneath an Italian mountain range, where the XENON1T experiment got some strange results … that might give us humans our first handle on what dark energy is and how to find it:
Everything our eyes can see in the skies and in our everyday world — from tiny moons to massive galaxies, from ants to blue whales — makes up less than five percent of the universe. The rest is dark. About 27% is dark matter — the invisible force holding galaxies and the cosmic web together — while 68% is dark energy, which causes the universe to expand at an accelerated rate.
“Despite both components being invisible, we know a lot more about dark matter, since its existence was suggested as early as the 1920s, while dark energy wasn’t discovered until 1998,” said Dr Sunny Vagnozzi from Cambridge’s Kavli Institute for Cosmology, the paper’s first author. “Large-scale experiments like XENON1T have been designed to directly detect dark matter, by searching for signs of dark matter ‘hitting’ ordinary matter, but dark energy is even more elusive.”
About a year ago, the XENON1T experiment reported an unexpected signal, or excess, over the expected background. “These sorts of excesses are often flukes, but once in a while they can also lead to fundamental discoveries,” said Dr Luca Visinelli, a researcher at Frascati National Laboratories in Italy, a co-author of the study. “We explored a model in which this signal could be attributable to dark energy, rather than the dark matter the experiment was originally devised to detect.”
The researchers used their model to show what would happen in the detector if the dark energy was produced in a particular region of the Sun, called the tachocline, where the magnetic fields are particularly strong.
“It was really surprising that this excess could in principle have been caused by dark energy rather than dark matter,” said Vagnozzi. “When things click together like that, it’s really special.”
You can read the XENON1T team’s dark energy findings here, in the journal Physical Review D.