Miller, who had endured a series of strokes, had a fatal heart attack Sunday at a hospital in National City (NYSE:NCC), Calif., his brother told The Los Angeles Times.

As a graduate student under Harold Urey in Chicago in 1952, Miller simulated the conditions Urey had deduced for the early Earth. He created a closed system containing methane, hydrogen, ammonia and water -- and within a few weeks, the system produced 13 of the 21 amino acids required for life.

"Stanley Miller was the father of origin-of-life chemistry," said Jeffrey L. Bada, a former graduate student of Miller's who became a colleague at UC San Diego. "And he was the leader in that field for many decades... . It was the Miller experiment that almost overnight transformed the study of the origin of life into a respectable field of inquiry."

Miller spent most of his career at UC San Diego. For decades, he tried, without success, to take his research to the next step by creating a living organism in the laboratory.