Daniele Sorini tells us about his research looking into how the value of dark energy affects star formation in the universe. He builds an analytic model of star formation in the universe, which allows him to follow the universe to very late times and ask “if Λ was different, how many total stars could form over the entire history of the universe?”

This is the crucial question one wants to ask when examining anthropic explanations of Λ scientifically. Previous studies have asked this question using simulations, forcing them to stop after a finite amount of time.

Fascinatingly, Daniele finds that there is a value of Λ where star formation peaks, which is about 0.1 times the value in our universe. Previous simulation-based studies maybe didn’t spot this because they simply didn’t do simulations with Λ less than our observed value, except for Λ=0, but also they didn’t go to late enough times.

When combined with a uniform prior for Λ he finds that our value, or a value smaller than it still only has a 0.5% chance, but with other priors one gets other results.

The paper: https://arxiv.org/abs/2411.07301

Daniele: https://www.danielesorini.com/