On December 26, 2024, scientists at the Gran Sasso National Laboratory in Italy are conducting experiments to detect dark matter by filling a particle detector with liquid xenon. This underground facility minimizes cosmic ray interference, allowing researchers to observe potential collisions between dark matter particles and xenon atoms.
Approximately one billion weakly interacting massive particles (WIMPs) are predicted to pass through the detector each second. However, no WIMPs have yet been detected, according to Dr. Abigail Kopec, an Assistant Professor of Physics & Astronomy at Bucknell University.
Dark matter, which constitutes about 26.8% of the universe, remains largely mysterious. The first indications of its existence emerged in the 1930s, and subsequent observations have reinforced the idea that unseen mass influences gravitational forces in the universe. Dr. Tracy Slatyer from MIT emphasizes the significance of discovering dark matter, stating it could reveal a hidden framework of the universe.
Current experiments focus on two primary hypotheses: whether dark matter is composed of WIMPs or axions, a theoretical particle suggested by quantum chromodynamics. Despite extensive searches, evidence for supersymmetry, a related theory, has not been found, leading researchers to consider alternative explanations.
Another theory proposes that dark matter could be lighter than known particles and behave like a wave, potentially resolving issues within the standard model of cosmology. Dr. Ciaran O'Hare from the University of Sydney notes that if dark matter were a QCD axion, it would be nearly undetectable.
Efforts to identify dark matter include experiments designed to detect sterile neutrinos and primordial black holes. While detecting black holes the size of asteroids poses significant challenges, researchers remain hopeful that advancements in technology and ongoing experiments will eventually yield results.
Despite decades of searching, scientists are optimistic about finding evidence of dark matter within the next decade. However, some experts caution that the elusive nature of dark matter may require new physics that is yet to be understood.