The Miller-Urey experiment makes amino acids from simple gases

In 1952 at the University of Chicago, the graduate student Stanley Miller and his professor Harold Urey built a glass apparatus in which water was heated and mixed with methane, ammonia and hydrogen, gases then thought to have been present in the early atmosphere, and exposed to electric sparks resembling lightning. After a week, the water had turned brown and contained several amino acids, the building blocks of proteins. The result, published in Science in May 1953, showed that the molecules of life can form naturally from simple ingredients, and started the experimental study of the origin of life. The assumed atmosphere is now thought to have been different.

Open on the timeline