|A simplified diagram of the Miller Urey Experiment.|
When multiple molecules of hydrogen cyanide are exposed to ultraviolet light, after multiple reaction stages, a chemical known as an imidazole intermediate, a compound vital in the formation of the nucleobases in DNA, the parts of the molecule which encode genetic information, is formed. This has been known since the 1960s. What remained unclear was how the UV light caused the formation of the imidazole intermediate?
Yet earlier this year, a computer model created by researchers from the Max Planck Institute in Germany, demonstrated something incredible: that this hydrogen cyanide reaction can occur in very common conditions rather than a precise set. 'This has nothing to do with heat, but with electrons,' said Mario Barbatti. Many organic reactions require a temperature range of between 0 and 100 degrees Celsius to occur which restricts their use in models of the origins of life to planets of such a temperature.
|The reaction scheme involving hydrogen cyanide and UV light.|
In order to react, each molecule must absorb hundreds of photons very quickly before the energy is dissipated. 'This is very inefficient and quite extraordinary,' said Barbatti. Finding a solution to this problem was the main challenge facing the researchers. After analyzing multiple possible intermediates, they found the imidazole intermediate, which fitted with previous research and the fast energy dissipation of the reactions. 'Some intermediates are too elusive to analyze them in the laboratory; they disappear before we may see them,' explained Barbatti.
A reaction which can occur in the depths of space is incredibly useful to the story of the origins of life. Analysis of nebulae and a number of planetary atmospheres has revealed the presence of hydrogen cyanide. Stars are powerful sources of UV radiation, meaning that this reaction could have very easily occurred in the nebula from which our solar system was formed, in the atmosphere of the early Earth and existing nebulae.