A new generation of scientists has managed to relight the interest in an experiment conducted by chemists Stanley L. Miller and Harold Urey more than five decades ago on the origin of life. What was once believed to be lost - the original vials used by Miller in his experiment - were found this year by his former students, Jeffrey Bada of Indiana University, Bloomington, and Jim Cleaves of the Carnegie Institution of Washington, one year after Miller’s death.

Everything started in 1953, when Miller and Urey based their experiment on the idea that life was formed in an atmosphere of methane, ammonia, water and hydrogen billions of years ago. Following this theory, Miller and Urey circulated the gases past an electric discharge, and further simulated the lightning conditions that presumably played an essential role in the formation of the primordial compounds in Earth’s atmosphere.

In a special apparatus, Miller heated water to create vapors that would later circulate though the apparatus, mix with the gases, circulate past the electrodes, condense and then return to the flask of hot water. After one week, the experiment yielded amino acids, which are the molecules used by cells in protein biosynthesis found in all forms of life.

In an interview dating back to 1996, Miller talked about his experiment and the reactions it had created: “most people thought I was at least a little bit crazy.” However, he said, he was confident that the methane/ammonia vs. CO2/nitrogen would be the best way to obtain organic compounds.

“The surprise of the experiment was the very large yield of amino acids,” he said, although they would have been happy with just obtaining traces of amino acids. “That was the start,” Miller recalled. “It all held together and the chemistry turned out to be not that outlandish after all.”

The results proved so amazing that they inevitably drew a note of reticence from observers, which resulted in a delay of the paper’s publication. Despite all that, “nobody questioned the chemistry of the original experiment, although many have questioned what the conditions were on the pre-biotic Earth,” Miller said. “The chemistry was very solid.”

Now, after all those years, Miller’s former students have stumbled upon the vials originally used in the 1953 experiment, and decided it was the perfect opportunity to re-examine them, this time by using the modern technology available today.

With the help of sensitive mass spectrometers at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, the re-analyzed the vials and found 22 amino acids in the residue left behind in the original experiment, twice as many as Miller and Urey had found.

Going further with the assumptions into Miller’s experiment, the new generation of scientists believes that volcanoes may have played an important role in forming life, due to the combination of molecules found in the eruption gas clouds. With still a lot of important elements missing from the equation, Bada and Cleaves present their findings in the October 17 issue of Journal Science.