What is the Miller-Urey experiment?
The Miller-Urey experiment, conducted in 1953, was a direct test of my hypothesis that organic molecules could form spontaneously on the primitive Earth. We built a closed apparatus containing water, methane, ammonia, and hydrogen—gases I believed were present in the early atmosphere—and subjected them to continuous electrical discharges to simulate lightning. After a week, we analyzed the brown residue and found several amino acids, including glycine and alanine. This was not speculation; it was experimental data showing that the fundamental components of life arise naturally from simple chemical reactions under plausible early Earth conditions. The experiment has been replicated and extended many times since, confirming that the chemistry of life is not a rare accident but a probable outcome of planetary evolution. It shifted the origin of life from philosophy to empirical science.
Ask Harold Urey the follow-up →