The Copernicus Complex: The Quest for Our Cosmic (In)significance, by Caleb Scharf

I have a list of things to see and do before I die. Some of them I’ve managed to complete: I’ve slept underground in a hotel constructed from a former opal mine in Coober Pedy; I’ve seen the sun rise over Monument Valley and watch fog roll into the Grand Canyon; and courtesy of a recent flight I’ve now seen the aurora borealis from a plane window. Thanks to astronomer Caleb Scharf’s The Copernicus Complex, I’ve had to add a new one to my list: to see the zodiacal light. This is sunlight scattered from the sparse interplanetary grains of dust that form a cloud between Mercury and Jupiter, the leftovers of the cosmic chaos that formed our solar system. It’s seen at dusk and just before dawn in some of the most remote places on Earth, which neatly ties in with my desire to visit the Paranal Observatory in Chile. One day.

In his latest book, Scharf seeks to work out whether we – the biological inhabitants of Earth – are significant. Are we, our planet and our solar system so normal and mundane that we should expect to see living planets distributed across the universe? Or are we the result of a sufficiently unusual coincidence of events that when we are (inevitably) gone, so too will life vanish? The book takes us from Aristarchus in ancient Greece, via the search for exoplanets and our realisation that there are some very odd things going on Out There, through to how on Earth we’re supposed to answer this question anyway. More importantly, can we answer this question, or are we so caught up in the apparently amazing fact of our own existence that we simply can’t find the right questions to ask? Are we too close to the problem?

This is an engaging book that covers a lot of scientific ground, but if you don’t like lyricism and whimsical turns of phrase in your science writing then this one might not be for you. Venus’ atmosphere is “broiling” whereas Mars’ is “dismally thin”, and planetary atmospheres are “fickle and leaky things”. Scharf speaks of a “stark and unnerving mathematical likelihood” that the “supposedly immutable glory” of our planetary system is illusory. That said, I am fond of a bit of hyperbole myself and I found it an enjoyable read. Scharf handles complex concepts gracefully – although the anthropic principle still gives me a headache – and he is convincing when he explains that although a series of apparently staggeringly unlikely circumstances gave us life on Earth, series of staggeringly unlikely circumstances are happening across the universe all the time. They might not always, or indeed often, lead to life, but we can’t rule it out until we understand the parameter space under which life might emerge.

Scharf ultimately argues that it all comes down to chaos and that the only way to get to the bottom of our cosmic significance is to harness all the existing and emerging tools of physics, chemistry and biology, experiment, theory and simulation, and throw the lot at the problem. This may sound a little unsatisfying. But Scharf ably describes how we have harnessed computer simulations to explain how apparently weird and wonderful exoplanetary systems were formed following a series of unpredictable events. He also makes the point that we examine the parameters required for life on Earth by sampling biological niches and looking at the richness of life found there. Scharf merely argues that we should do the same on a cosmic scale. It’s a grand ambition.