TWO MINUTES WITH Adam Frank

For how long have humans pondered the existence of life beyond Earth?

For thousands of years. The ancient Greeks were arguing about it. In the medieval period the Church made it heresy to discuss ‘other worlds’. After Newton, people became pretty optimistic that the heavens were full of life. By the beginning of the 20th century, however, scientists had reason to think that planets were rare and therefore life was too. Now we know almost every star in the sky has planets.

It seems we are only just starting to take the idea of alien life seriously.

Recently discovering there are 10 billion trillion planets in the right place for life to form pushed us to take alien life seriously. Exploring our own Solar System for 50 years has also given us profound insights into the possibilities for life. We’ve just become a spacefaring race and we’ve triggered climate change. This makes us see ourselves as a true planetary species. That makes us ask, “Have there been others?” with a new urgency.

What might the prospect of life on other worlds tell us about our own planet?

As I’ve shown in my research and in the book, any technological civilisation that emerges on any planet will likely trigger some form of climate change. We’re like cosmic teenagers and not the first to go through this. The question is, then, are we smart enough to be counted among the cosmic civilisations that make the right choices and see it through?

ADAM FRANK is a professor of astrophysics at the University of Rochester, New York