Why this is a golden age for life to thrive across the universe

This story is part of our Cosmic Perspective special, in which we confront the staggering vastness of the cosmos and our place in it. Read the rest of the series here.

Since the opening act of the universe 13.8 billion years ago, a diverse set of characters have trod the boards – stars, planets, moons, quasars. But if you tend to get fidgety at the theatre, there is bad news: this cosmic performance has at least 100 billion years to go. Which raises a question: are we living at a special moment – the cliffhanger before the interval – or is this just an inconsequential moment in the mid-plot?

One hint that this is a special instant involves a swathe of observed properties of the universe known as fundamental constants. These include the strength of gravity, for example, and the fine-structure constant, known as alpha, which determines the way matter and light interact and thus how stars burn. If these numbers were just a shade different from how they are, then life might be impossible.

Why is it all so perfect? One possible answer is that these constants aren’t so constant. Perhaps they have been gradually changing over the life of the universe and we happen to live at an auspicious blip in time. John Webb at the University of Cambridge has spent decades investigating this idea,…