A newly unearthed essay by Winston Churchill reveals that the British politician "reasoned like a scientist about the likelihood of life on other planets".
Churchill's 11-page typed article, probably intended as a popular science piece for a newspaper, was drafted in 1939 when Europe was on the brink of war. Churchill added to it in the 1950s but it was never published.
The essay passed to the US National Churchill Museum in Fulton, Missouri, in the 1980s. The incoming museum director unearthed it last year and handed it to astrophysicist Mario Livio "for examination of the science".
Livio has revealed that Churchill considered possibilities that mirror issues in astrobiology research today.
Churchill defines life as the ability to "breed and multiply", and notes the importance of liquid water and that a planet's temperature must be "between a few degrees of frost and the boiling point of water" for life to survive.
He concludes "I, for one, am not so immensely impressed by the success we are making of our civilization here that I am prepared to think we are the only spot in this immense universe which contains living, thinking creatures."
You can read Livio's full analysis of the essay here.