Researchers from the UK’s University of Kent, Imperial College London, and Lawrence Livermore National Laboratory discovered a “cosmic factory” that produces amino acids – the building blocks of life – when a rocky meteorite impacts a planet with an ice-covered surface, or when an icy comet impacts a rocky planet, according to a September 16 news release. The research findings appear in the latest issue of the journal Nature Geoscience.
The team of researchers hypothesized that this process is yet another piece to the puzzle of how life began on Earth between 4.5 and 3.8 billion years ago, when the surface experienced successive bombardments by comets and meteorites.
“This process demonstrates a very simple mechanism whereby we can go from a mix of simple molecules, such as water and carbon-dioxide ice, to a more complicated molecule, such as an amino acid,” said Dr Mark Price, co-author of the paper from the University of Kent. “This is the first step towards life. The next step is to work out how to go from an amino acid to even more complex molecules such as proteins.”
“Our work shows that the basic building blocks of life can be assembled anywhere in the Solar System and perhaps beyond,” added Dr. Zita Martins, co-author from the Department of Earth Science and Engineering at Imperial College London. “However, the catch is that these building blocks need the right conditions in order for life to flourish. Excitingly, our study widens the scope for where these important ingredients may be formed in the Solar System and adds another piece to the puzzle of how life on our planet took root.”
According to the researchers, the bounty of ice on the lunar surfaces of Saturn’s Enceladus and Jupiter’s Europa could provide the ideal environment for amino acid production when meteorites impact their surfaces. Their research reinforces the significance of future space missions to these moons to hunt for signs of life.
The researchers learned that when a comet impacts a planet, the ensuing shock wave produces molecules that make up amino acids. In addition, the impact of the shock wave generates heat, which then transforms these molecules into amino acids.
The researchers realized their discovery by reconstructing the impact of a comet by firing projectiles through a large high-speed gun. This gun, sited at the University of Kent, uses compressed gas to launch a projectile at speeds of 7.15 kilometers per second (4.44 miles per second) into targets of ice mixtures of similar composition to comets. The resulting impact produced such amino acids as glycine and equal amounts of D-and L-alanine.