There should be worlds out there so balmy they make Earth look stale, and there are signs of one just four light years away. That's close enough to visit...

Matthew Borret

“WHEN I was a kid, I was always looking at Alpha Centauri,” says Eduardo Bendek. One of the things he discovered about it while growing up in Chile was that our closest neighbouring light had a secret: it is not one star, but two.

More than 30 years later, Bendek, now an astronomer at NASA’S Ames Research Center, suspects that his favourite celestial beacon might just be hiding another, more marvellous secret. There could be a planet orbiting one of the stars. And not just any old space rock. This could be a place so bursting with life that it makes Earth look post-apocalyptic.

And at a mere 4.4 light years away, we might feasibly develop a probe that could visit within decades. That’s precisely what a project backed by Stephen Hawking and billions of dollars now plans to do. We could catch our first glimpse of this bucolic world within a generation.

We are used to thinking small when it comes to alien life. Our list of living worlds has a sole data point, Earth, and even our convivial planet seems to have been a tricky place for life to get started. How could we expect more than a self-replicating bag of biomolecules anywhere else?

That might be too lofty a view of Earth. After all, huge areas of our planet, including the poles and deserts, are rather barren. And whole epochs of time were inhospitable to life.

Time was perhaps the most important attribute identified by astrophysicist René Heller of the Max Planck Institute for Solar System Research in Gottingen, Germany, when in 2015 he was …