The origin of life was highly speculative until agraduate student at the University of Chicago, Stanley Miller designed and conducted an empirical research project under the guidance of his graduate advisor, Harold Urey. In this classic experiment, the re

The origin of life was highly speculative until agraduate student at the University of Chicago, Stanley Miller designed and conducted an empirical research project under the guidance of his graduate advisor, Harold Urey. In this classic experiment, the researchers tried to simulate the chemical evolution that generated life. Miller and Urey took a five-liter flask half filled with water and connected it with glass tubing to another flask into which they inserted tungsten electrodes. They then mixed methane,hydrogen, and ammonia into the waterin the lower flask and heated it to induce evapouration, while at the same time subjecting it to continuous electrical chargesthat jumped across the space between the electrodes in the upper flask. The atmosphere was cooled againso that the water could condense and trickle back into the first flask in a continuous cycle. In this way, they sought to recreate conditions in the early atmosphereof earth, which they speculated was probably subjected to powerful electrical storms. In about an hour, the water turned orange. At the end of the first week, they observed that almost 15 percent of the carbon was converted into organic compounds. After several weeks, the liquid in the flask clouded and then gradually turned adark brown. When they analyzed it,Miller and Urey found that it contained alarge number of amino acids, which form one of basic structures of living organisms. They then hypothesizedthat the amino acids they had created in the laboratory might be typical of chemical mixtureof early oceans on earth, and further that additional amino acids could have been added to the mixture in the early oceansby carbon enriched meteoritesor comets.
When the scientific results were popularized, the mixture became known as ' primordial soup'. However, much was still nknown about the process that caude the first cell to develop within the soup.The molecules produced were relatively simple organic molecules, not acomplete living biochemical system. Nevertheless, the experiment established that natural processes could produce the building blocks of life without requiring life to synthesize them in the first place.The experiment served as inspiration for alarge number of further investigations.