Winston Churchill: alien life is out there

They have built pyramids on Mars. They crashed in the desert, and the US government has covered it up. They have left messages in crop circles.

These are some of the conspiracy theories around aliens’ existence. Such stories may be far-fetched. But yesterday it emerged that one of the 20th century’s most revered leaders thought extra-terrestrial life may exist.

Historians in the USA found an unpublished article, entitled Are we alone in the universe? It was written in 1939, the year the second world war began, by Winston Churchill.

He referred to the hostile international climate: ‘I am not so immensely impressed by the success we are making of our civilisation here that I am prepared to think we are the only spot in this immense universe which contains living, thinking creatures,’ he wrote.

Some of his ideas now look prophetic. He predicted that other stars could host planets. He said life could exist in a narrow region around each star, and a large fraction of distant worlds would be the right size to keep ‘water and possibly an atmosphere’.

So was he right about alien life? Many scientists now think so. In 1961 Frank Drake proposed a calculation called the Drake equation, to estimate the probability that life existed on other planets. At the time the values needed to perform it were mostly unknown.

But last year two American physicists reached two striking conclusions. Even if only one in every million stars hosted a technologically advanced species, they said, there would be around 300,000 such civilisations in the Milky Way alone. And there is just a one in 60 billion chance that no advanced species has existed in our galaxy outside Earth.

Their suspicions may soon be confirmed. In 2014 Seth Shostak of SETI estimated that alien life would be detected by 2040. In 2016 some thought it had happened, when a star was found giving out unusual patterns of brightness. Scientists now think they were wrong and it had swallowed up a planet. But has this just delayed the inevitable?

Light years away

We cannot be alone, say some. It is simple logic: if life can evolve on Earth, it can evolve anywhere. Even when we study our own galaxy — a tiny portion of the universe — the mathematics is overwhelming. Churchill was right: human beings should have the humility to realise that evolution could produce something more advanced than us.

Remain sceptical, say others. The Drake equation still relies on wild guesswork because we know so little about the universe and life’s origins. We have no idea, for example, how likely a civilisation is to develop on any habitable planet. And we should consider Fermi’s paradox: if aliens existed, we should know about it by now.