The Lifespan of our Universe

The Dark Energy Survey (DES) and the Dark Energy Spectroscopic Instrument (DESI) measurements claim that the dark energy equation of state $w\mathrm{\ne }-1$. This observation can be explained by the axion Dark Energy (aDE) model of an ultralight axion plus a cosmological constant $\mathrm{\Lambda }$. Despite a relatively large degeneracy, there is a high probability that $\mathrm{\Lambda }<0$. This negative $\mathrm{\Lambda }$ 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.