Cosmic Factory for Producing Amino Acids
Blog Sep 16, 2013
A team from Imperial College London, the University of Kent and Lawrence Livermore National Laboratory have discovered that when icy comets collide into a planet, amino acids can be produced. This process may provide another piece to the puzzle of how life was kick-started on Earth.
To learn more about this research, I caught up with Dr Zita Martins, co-author of the paper from the Department of Earth Science and Engineering at Imperial College London.
AB: Reading your Nature Geoscience paper I came across the term, "Impact-shock synthesis". Can you explain how this may be responsible for organic carbon in our solar system?
Zita Martins (ZM): We know that impacts are common in our solar system because we observe impact craters in planetary bodies. When a comet impacts a rocky planet or when an asteroid impacts a planet that has an icy surface, the impact velocity is in the order of kilometres per second. The pressure and temperature are very high in those situations, which may lead to the formation of new chemical molecules. Therefore a nice distribution of simple and complex organic compounds, in particular the building blocks of life (such as amino acids) are widespread throughout the solar system, significantly increasing the locations where life may have originated.
AB: How were the conditions of a meteorite collision reproduced in a laboratory?
ZM: We have replicated the impact of a comet by firing projectiles into targets of ice mixtures with similar composition to comets. This was done using a large high speed gun located at the University of Kent. The resulting impact created amino acids such as glycine and equal amounts of D-and L-alanine.
AB: What were the key findings from this research?
ZM: We have found that the impact of a comet into a planet leads to the formation of amino acids. These essential building blocks of life are also produced if a rocky meteorite crashes into a planet with an icy surface, such as Enceladus and Europa, which are moons orbiting Saturn and Jupiter respectively.
AB: Were you confirming a hypothesis or did the production of amino acids come as a surprise?
ZM: One of the co-authors of the paper, Dr. Nir Goldman from the Lawrence Livermore National Laboratory had performed computer modelling that suggested that amino acids could be formed via an impact-shock process. But he could not support this with experimental data.
Dr. Mark Price from the University of Kent realized he could experimentally replicate Dr. Nir's simulations in the laboratory. He then contacted me at Imperial College as I have the expertise to detect amino acids in planetary environments. This process (until obtaining reproducible results) took approximately 3 to 4 years. This is a good example of how important it is to collaborate with scientists from different research areas. Working as an international and interdisciplinary team we managed to experimentally show that the impact of a comet into a planet leads to the formation of amino acids, increasing the chances of life being present in other parts of our solar system (such as the icy moons Enceladus or Europa)
AB: How will the findings from this paper impact future research?
ZM: Our research shows that molecules that are required for life (i.e. amino acids) were formed via impact-shock from much simpler compounds present at the time of the birth of the solar system. It has implications for the detection of life in Enceladus and Europa (the moons of Saturn and Jupiter respectively), which have icy surfaces.
The next step in our research may be to determine whether we can shock synthesise a peptide starting from a mixture of amino acids.
The full paper, published in Nature Geoscience, can be found here.