Miller-Urey experiment. Illustration showing the apparatus used in the Miller-Urey experiment to study the origin of life. This 1950s experiment attempted to duplicate the conditions that would have existed on the primordial Earth. The apparatus contains a 'sea' of sterile water and an 'atmosphere' of hydrogen, methane and ammonia. Electrodes give off a spark within the 'atmosphere' to imitate either lightning or ultra-violet radiation from the Sun. The result is a tar-like residue containing amino acids, the basic building blocks of life.