Life in the universe

One of the most remarkable aspects of the universe is that it’s given rise – at least once – to intelligent life. Life of any kind is only possible because of a handful of basic parameters of nature, such as those which control the strength of forces within and between atoms and those that permit the existence of a stable universe at all.

The precise values of these parameters allow the creation of stable elements, the existence of habitable planets and the formation of complex molecules.

Instinctively it may feel like this level of ‘fine-tuning’ is too big a stroke of good fortune to happen by chance, but the so-called anthropic (humancentred) principle points out a possible flaw in this logic: we shouldn’t be too surprised that the universe seems fine-tuned for our existence because if its properties were slightly different, we simply wouldn’t be around to measure them.

A more immediate question, however, is whether life elsewhere in the cosmos is rare or widespread? Breakthroughs in recent decades, such as the discovery of abundant exoplanets orbiting other stars, have shown that raw materials and suitable habitats for life are certainly widespread, but we still can’t be sure that life will always arise wherever conditions are broadly hospitable or whether we’re overlooking some vital factor.