Book review: Five Billion Years of Solitude

When you look up at the stars on a clear night sky it’s difficult not to wonder whether there are conscious, sentient, intelligent beings somewhere out there. And if you accept for a moment their existence, a host of questions follow. What do they look like? Do they create art or make music? Do they believe in god? What is their understanding of space and time? Then another question intrudes, or at least it does whenever I find myself pondering these things: what if they aren’t there? What if humanity is the only species in the universe capable of wondering whether it is alone?

In Five Billion Years of Solitude: the Search for Life Among the Stars, Lee Billings records his discussions with a number of luminaries in the nascent field of astrobiology. Along the way Billings provides crystal-clear descriptions of the science behind the quest for exoplanets, the difficulties of SETI research, the technology with which we might find biosignatures on distant worlds, and much else besides. He gives a masterclass in how to make complex ideas accessible.

But the book is much more than that. The scientists he interviews are driven by competition, ego, rivalry – as are many achievers in various activities; science is not unique in this regard – but they are also united by an overwhelming desire to know whether we are alone in the universe. This makes their accounts both exciting and bitter-sweet. The final chapter in particular, which tells the story of how Sara Seager, a professor of planetary science and physics at MIT, came to find herself searching for the first truly Earthlike planet, is achingly beautiful.

Seager, Marcy or Kasting, or one of the many other scientists interviewed by Billings, might one day find life out there. But it’s entirely possible that they’ll fail (in my view it’s almost certain that they will fail). Earth, this precious blue marble, might be home to the only intelligent life in the universe. Reading Five Billion Years of Solitude will give you an appreciation of the true poignancy of that thought.