Cosmic collisions may be able to generate the building blocks of life, a new study suggests. A team of British researchers have determined that the collision between an icy comet and a rocky planet can produce amino acids –– the sophisticated carbon-based compounds that underpin life as we know it. The findings add to the the growing body of evidence indicating that Earth’s biological diversity was kickstarted by a cataclysmic event.
Published in the journal Nature Geoscience, the research effort aligns with the common scientific notion that organic life began between 4.5 and 3.8 billion years ago, when Earth was still relatively young. During this era, the solar system was marked by an extremely violent and unstable cosmic climate, and its planets were constantly bombarded with debris, comets, and meteorites. This period, researchers say, may have been crucial to the initial formation of prebiotic compounds and, subsequently, rudimentary forms of life.
Co-author Zita Martin of the Department of Earth Science and Engineering at Imperial College London said that her team's findings suggest that life may not be exclusive to Earth, as its catalytic processes can occur virtually anywhere in the universe.
"Our work shows that the basic building blocks of life can be assembled anywhere in the Solar System and perhaps beyond,” Martins said in a press release. “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."
To test their hypothesis, the scientists recreated the proposed comet impact by firing high-velocity projectiles into ice mixtures at 7.15 kilometers per second. The collision generated amino acids such as glycine and D- and L-alanine.
"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 co-author Mark Price of 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."
The findings suggest that while liquid water may be a prerequisite of sustained life, its frozen configuration could play an important part in life’s initial formation. According to the researchers, this discovery underscores the importance of exploring Enceladus, Europa, and other icy moons believed to harbor life.
Source: Martin, Z., Price, M., Goldman, M., Sephton, M., Burchell, M. Shock synthesis of amino acids from impacting cometary and icy planet surface analogues. Nature Geoscience. 2013.