Volcanoes and lightning may have provided the vital spark that kick-started life on Earth, a new study has suggested.

To come to the conclusion, researchers, led by the University of California at San Diego, used modern techniques to re-analyse results from a 1950s experiment — in fact, they studied “primordial soup” gas samples created by U.S. Prof. Stanley Miller in 1958.

The researchers discovered a multitude of amino acids, the basic building blocks of life, which can be assembled together to form proteins, the Daily Mail reported.

In 1953, Prof. Miller conducted the famous experiment in which he attempted to recreate the atmospheric conditions present just before life appeared on Earth around four billion years ago. By sending an electric spark through a mixture of methane, ammonia, water vapour and hydrogen to simulate lightning, he generated several simple amino acids and other organic compounds.

But the original ‘primordial soup’ was a little thin. It did not contain a rich enough array of organic chemicals to produce the complex structures needed for life.

For his 1958 experiment, Prof. Miller took the crucial step of adding hydrogen sulphide — an evil-smelling toxic gas released by volcanoes — to the mix. The new samples he created at Columbia University were shelved, but not analysed.

Now, Prof. Jeffrey Bada, one of Prof Miller’s students, led the California University team to study the samples using modern techniques some 1,000 times more sensitive than earlier available to his teacher.

The findings revealed a plethora of organic compounds, including 23 amino acids. Around 20 amino acids, linked together in chains, make up the proteins that provide the material for building cells and all the organic machinery of living things.

The abundance of amino acids was greater than that produced in Prof. Miller’s original “primordial soup” experiment and two other follow-up studies.

The California University team was also able to improve on the results of a 2008 re-analysis of the original samples which made use of modern techniques.

“Much to our surprise, the yield of amino acids is a lot richer than any experiment Miller had ever conducted.

This really not only enhances our 2008 study but goes further to show the diversity of compounds that can be produced with a certain gas mixture,” Prof. Bada said.

The findings support the theory that volcanoes played a key role in the creation of life. Volcanic eruptions are a major source of hydrogen sulphide and lightning discharges, and were much more common when the earth was young.

Prof. Bada also found that the amino acids in Prof. Miller’s samples were similar to those found in meteorites, indicating that processes involving hydrogen sulphide may have helped spread the seeds of life throughout the solar system.

The findings have been published in the Proceedings of the National Academy of Sciences journal.

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