In experiments at Stanford University, chemists discovered that microdroplets in fine sprays of water generate streaks of “microlightning”. When surrounded by the right mix of gases, these sparks power chemical reactions that synthesise many molecules for life.

Prof Richard Zare, a chemist who led the team, said: “This is a real contribution to understanding how you can go from non-life to life. You have water sprays all over the place, particularly around rocks, and there are crevices in rocks where these chemicals can accumulate.”