school energy&environment

Miller’s experiment

In 1952 the American professor Harold Clayton Urey, Nobel prize for chemistry in 1934, asked a young researcher, Stanley Lloyd Miller, to perform an experiment. Inside a glass bottle, Miller put some extremely hot water and in another one he put a Hydrogen mix (H₂). ammonia (NH₃) and methane (CH₄), which are all those gasses that combined with water vapour (H₂O)were thought to have created the primordial atmosphere. Hot water, which according to scientists was in the primitive ocean, created vapour that passed through a tube and went to the container that held the gas mix. Inside this container they generated 60.000 volt electric discharges so as to reproduce the probably very frequent and powerful storm phenomena which occurred at the time when the planet was forming. The experiment was carried out for a whole week and in the end they were amazed to see that in the water container there was a red – orange liquid which had many compounds, particularly some amino acids, that are the precursors of proteins that are the main components of every living being.
Miller’s experiment proved that from simple compounds, that were thought to be in the primordial atmosphere, there could be the formation of complex molecules, those that are found in organic compounds of all living organisms. So the assumption was that the biologic precursors of living beings could have formed with a simple chemical synthesis process in a primitive atmosphere with frequent storm phenomena, heat and ultraviolet radiation. After that rains would have carried these simple organic compounds to the sea, where they could subsequently change and grow.
Anyway, creating amino acids in a laboratory doesn’t mean that one is creating a living organism, but obviously this was a step forward in the abiotic (that is chemical) formation of living beings.
From then on scientists performed many variations of Miller’s experiment. It is possible to modify the gas mixture, change the temperature, use a different energy form from electric discharges, but the final result will always be the same: organic substance.