Cometary Collisions Could Have Created Life On Earth

Article written: 17 Sep , 2013
Updated: 23 Dec , 2015
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The energy of comets smashing into Earth billions of years ago could have generated life out of the building blocks of life that those extraterrestrial objects brought, according to new experiments published in a peer-reviewed study.

The finding comes after a team “shock compressed” an icy slush similar in composition to that found on comets, which are sometimes called “dirty snowballs” because they are a mixture of ice and rock. The compression, which researchers say is similar in intensity to comets hitting the Earth, generated amino acids – considered the basic bits of life.

“Our work shows that the basic building blocks of life can be assembled anywhere in the Solar System and perhaps beyond,” stated Zita Martins, a co-author of the paper who is with Imperial College London’s department of Earth science and engineering.

“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.”

An object entering a planet's atmosphere. Credit: Imperial College London

An object entering a planet’s atmosphere. Credit: Imperial College London

Whether life arose on Earth, or was imported from other locations in the Solar System or universe, has been a hot-button topic for decades. Learning the answer not only has implications for our own planet, but also for understanding how likely it is that life exists in other Solar System planets and moons — not to mention moons or planets in other star systems.

The new experiment — which the researchers say uncovers evidence of a “cosmic factory” process for starting life — saw the team at the University of Kent and the Imperial College using a gas gun to send a projectile into an ice combination similar to what one would find a comet. After the impact, the researchers saw amino acids forming.

The work builds on research initially done by Nir Goldman, a scientist with the Lawrence Liverpool National Laboratory, who predicted the results based on simulations in the laboratory’s supercomputer. Goldman found that comets could have imported life’s building blocks (ammonia, methanol, carbon dioxide and water). Then, as they smashed into Earth, the energy produced could be enough to jump-start life.

The building blocks of proteins are molecules called amino acids. Most types of amino acids can exist in two different forms, one that is 'left-handed' and the other as 'right-handed.' Credit: NASA

The building blocks of proteins are molecules called amino acids. Most types of amino acids can exist in two different forms, one that is ‘left-handed’ and the other as ‘right-handed.’ Credit: NASA

“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,” stated Mark Price, a co-author and physicist 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.”

You can read the research paper, which was published Sept. 15, on Nature Geoscience.

Sources: Imperial College London and Lawrence Livermore National Laboratory



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