Describe the experiment conducted by S.L. Miller and write its contribution towards origin of life on earth.
Answers
There are a plethora of detailed online descriptions of the experiment Miller performed. Its present status within science, is more nostalgic than scientifically accurate.
Miller was testing the theory of his mentor, Harold Urey, who posited a naturalistic mechanism that could have significantly advanced the development of the first life. Potentially, if the right balance of elements, atmosphere, fluids and energy discharge could be placed under conditions that were not overly severe, could complex biochemical assemblies result, even forming simple living organisms.
So, elements and materials that were believed to constitute the original Earth conditions were placed in a sealed container and lightning was chosen as a potential energy source that was present. After several days of electrical discharge onto the materials, some simple abiotic compounds formed, primarily a dark colored tar-like material.
The contribution of the experiment was to show the futility of the approached used. No significant compounds resulted. Though some simple amino acids were produced, not the 4 used in DNA to intelligently design life, they were not homochiral, meaning they were left and right handed, while DNA requires 100% left-handed amino acids.
It was eventually found that the atmospheric gases used were not consistent with what primordial Earth conditions were made of. The ultimate verification that the Miller-Urey experiment resulted in no positive outcome, nonetheless, the role of science is to propose and experiment, so what was revealed has scientific value, even if its contribution towards the origin of life on Earth is no longer considered viable. It remaining contribution is nostalgic and historical.