Their research suggests that comets may have delivered the necessary ingredients to create amino acids, the building blocks of proteins, from space.
Professor Ramanarayanan Krishnamurthy and his team exposed a mixture of water, ammonia, carbon monoxide and hydrogen cyanide contained in a steel chamber to ultraviolet (UV) light. These experiments produced amino acids like glycine and alanine, crucial components for protein formation, and other important organic molecules found in living cells.
The team used the chamber to mimic conditions likely to have existed on the early Earth during its formation 4.5 billion years ago. Although earlier experiments had shown that exposing the mixture to UV radiation could produce organic compounds, this is the first time that the synthesis of amino acids under similar conditions has been described in a scientific publication.
During their experiments the researchers focused particularly on the chemical structure of hydrogen cyanide, which contains carbon, hydrogen and nitrogen atoms. These three atoms are the basic components of amino acids and therefore essential to the formation of life as we know it.
“What the results of our study provide is a more complete understanding of the origin of amino acids and the emergence of life on Earth,” Krishnamurthy says in a statement.
Krishnamurthy’s team says their findings offer another perspective on the much debated question of whether life on Earth started from inorganic molecules naturally present on our planet or from compounds brought here from space.
“The findings of our research team strengthen the case for the theory of panspermia,” Krishnamurthy says. Panspermia is the hypothesis that life originated outside Earth and was transported to the planet by celestial objects such as comets or meteoroids.
The possibility that life on Earth started with help from comets and meteoroids is also supported by other scientists, including Stephen Hawking and the late Carl Sagan.
The Cornell-Scripps team hopes that their findings will help narrow down the search for life outside Earth to celestial bodies that contain a mixture of water, carbon monoxide, ammonia and hydrogen cyanide, which are commonly found in comets.
