Dark energy, the mysterious force that makes the universe accelerate, could have been responsible for the unexpected results of the XENON1T experiment, located below the Apennines of Italy.
Have we detected dark energy?
The visible universe, the galaxies, the stars … all this hardly represents less than 5% of the universe. What is left? Darkness. About 27% of our cosmos is made up of dark matter, that invisible force that holds galaxies and the cosmic web together. The remaining 68% is dark energy, causing the universe to expand at an accelerating rate.
Now, new research, led by researchers at the University of Cambridge (England), suggests that some inexplicable results of the experiment could have been caused by dark energy, and not by dark matter, which is what such an experiment was designed for. .
The researchers built a physical model to help explain the results. The bottom line is that this work could indicate an important step in detecting dark energy from dark energy particles produced in a region of the Sun with strong magnetic fields.
Dark matter, dark energy
“Although both components are invisible, we know much more about dark matter, as its existence was suggested as early as the 1920s , whereas dark energy was not discovered until 1998,” comments Sunny Vagnozzi of the Kavli Institute of Cambridge cosmology and study leader published in the journal Physical Review D. “Large-scale experiments like XENON1T have been designed to directly detect dark matter, looking for signs that dark matter ‘hits’ ordinary matter, but dark energy is even more elusive .”
How is dark energy detected?
What scientists do is they look for gravitational interactions: the way that gravity pulls objects along. And, on larger scales, the gravitational effect of dark energy is repulsive, pulling things away from each other and accelerating the expansion of the universe. And this is what, about a year ago, the XENON1T experiment detected: an unexpected signal on the background. A casuality?
“We explored a model in which this signal could be attributed to dark energy, rather than the dark matter for which the experiment was originally designed,” the authors clarify.
They started from a model to show what would happen in the detector if dark energy were produced in a particular region of the Sun, called the tachocline , where 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, ” Vagnozzi said. “When things fit together like this, it’s really special.”
Many more experiments will be necessary in the future to confirm this hypothesis, but if the excess was the result of dark energy, the next updates to the XENON1T experiment would represent the possibility of directly detecting dark energy in the next decade.
Referencia: Sunny Vagnozzi, Luca Visinelli, Philippe Brax, Anne-Christine Davis, Jeremy Sakstein. Direct detection of dark energy: The XENON1T excess and future prospects. Physical Review D, 2021; 104 (6) DOI: 10.1103/PhysRevD.104.063023