The concept of particles traveling faster than light, named tachyons, though largely theoretical and unobserved, holds an intriguing place in recent cosmological models.
According to a study not yet peer-reviewed, our Universe could be dominated by these tachyons. These hypothetical particles challenge foundational concepts such as causality, where time flows from the past to the future.
In this new proposal, tachyons might be the true nature of dark matter, the mysterious component that makes up the majority of the mass of almost all galaxies in the Universe, surpassing normal matter at a ratio of 5 to 1. Dark matter, still unidentified, fuels researchers' imaginations to devise various hypotheses.
The tachyon model suggests that a Universe expanding filled with tachyons could initially slow down its expansion before reaccelerating. Currently, our Universe is in a phase of acceleration, a phenomenon attributed to dark energy. Thus, this model could potentially explain both dark matter and dark energy.
To support their idea, physicists have applied their model to observations of Type Ia supernovae. These stellar explosions provide cosmologists with valuable data to establish a relationship between distance and the rate of expansion of the Universe. The fact that the tachyon model matches the data from supernovae as closely as the standard cosmological model is a surprise.
A Type Ia supernova observed in the galaxy M82 by the Hubble Space Telescope. These explosions allow astronomers to estimate the rate of expansion of the Universe.
Credit: NASA Goddard
The next steps include testing this model with other cosmic data such as the cosmic microwave background and the large-scale distribution of galaxies.