The lifespan of our universe

Abstract

The Dark Energy Survey (DES) and the Dark Energy Spectroscopic Instrument (DESI) measurements claim that the dark energy equation of state w ≠ -1. This observation can be explained by the axion Dark Energy (aDE) model of an ultralight axion plus a cosmological constant Λ. Despite a relatively large degeneracy, there is a high probability that Λ<0. This negative Λ leads the universe to end in a big crunch. Using the best-fit values of the model as a benchmark, we find the lifespan of our universe to be 33 billion years.