Conditions on Earth were much different four billion years ago. There was almost no oxygen in the atmosphere; it was hotter; and there was a lot of lightning and volcanic activity.

In this primordial environment, amino acids formed – a fundamental component for life to have developed on earth.

But one question scientists have been asking is how these molecules came to be? Did they just spontaneously assemble? A pair of scientists believed that's what happened and in the 1950s created conditions similar to early Earth to test their theory.

Stanley Miller and Harold Urey injected various gases including methane, hydrogen, and ammonia into an experimental apparatus containing warm water. They used electrical discharges to simulate lightening, and a condenser allowed water and other molecules to rain back into the mini ocean.

Over the next few days the clear water turned an opaque brown color. Amazingly, they detected organic compounds, including amino acids, precursors to proteins which are essential building blocks of life.

Recently, Scientists made a surprising discovery. They found archived samples from a later experiment done by the same group. But for some reason, the samples where never processed.

This experiment, done several years after the original, included additional gases, like hydrogen sulfide, that more closely model a region with volcanic activity.

The archived samples were recently processed using today's advanced technology and researchers found an even more diverse distribution of amino acids than Miller's previous experiments. In these studies, it certainly appears that pre-biotic molecules could be formed from early Earth's basic components.