New Data suggests Dark Energy May Not Be constant, Pointing to New Particle Physics
Recent analysis of cosmological data from multiple large-scale surveys – including teh Dark Energy Survey (DES), Dark Energy Spectroscopic Instrument (DESI), Sloan Digital Sky Survey (SDSS), Time-Delay COSMOgraphy, Planck, and the Atacama Cosmology Telescope – indicates that dark energy, the force driving the accelerated expansion of the universe, may not be a cosmological constant as previously assumed. Rather, the data hint at a dynamic dark energy density that decreases over time.
This research, led by Anowar J. Shajib and joshua A.Frieman, suggests the possibility of a new basic particle, an axion, approximately 38 orders of magnitude lighter than the electron. The behavior of this hypothetical particle over billions of years would align with the observed decrease in dark energy density. Unlike a constant dark energy, this model proposes that dark energy evolves, much like a ball rolling down a slope, gradually losing potential energy.
The implications for the future of the universe are meaningful.If dark energy’s density diminishes, the rate of accelerated expansion will also slow down. This contrasts with scenarios like the “Big Rip,” where expansion accelerates uncontrollably, or the “Big Crunch,” where the universe eventually collapses. The current findings suggest a “Big Freeze” scenario – a future of continued, but decelerating, expansion leading to a cold and dark universe.
While the practical applications of these findings are currently focused on the progress of advanced technologies for further cosmological exploration – including new telescopes, satellites, and detectors – the potential impact on fundamental physics is profound. For two decades, cosmological data had consistently supported the idea of a constant dark energy. This new evidence represents the first indication in over 20 years that dark energy might be evolving, potentially requiring a revision of our understanding of the universe’s composition and behavior.
Shajib emphasized the collaborative nature of this research, highlighting that the results represent a synthesis of data gathered from numerous extensive experiments within the cosmological community. Frieman noted the excitement of revisiting a fundamental question after years of data supporting a different conclusion, stating that while the hints could prove incorrect, the possibility of answering this question is a significant step forward.
The research has been published in phys. Rev. D (DOI: 10.1103/kjpb-r698).
