Comets May Reveal Cosmic Origin of Life on Earth

First Posted: Mar 05, 2013 02:55 PM EST

Life on Earth may have had its origin in space. A new study that simulated conditions in deep space reveals that comets could have seeded the essential building blocks of life on our planet.

Published online in The Astrophysical Journal, the study examined the possibility of creating complex, organic compounds in space. The researchers used an ultra-high vacuum chamber chilled to 10 degrees above absolute zero (10 Kelvin) in order to simulate an icy snowball in space. This "snowball" included carbon dioxide, ammonia and various hydrocarbons such as methane, ethane and propane. The researchers then zapped it with high-energy electrons in order to simulate the cosmic rays in space. When zapped, the chemicals reacted to form complex, organic compounds. In particular, they created dipeptides, which are linked pairs of amino acids. Shared by all living things, they're essential to creating life.

These organic residues were then analyzed through the Mars Organic Analyzer at UC Berkeley. The instrument was designed for ultrasensitive detection and identification of small organic molecules in the solar system. In all, the analysis revealed the presence of nine different amino acids and at least two dipeptides.

Previously, scientists had discovered basic organic molecules, such as amino acids, in numerous asteroids that have fallen to Earth. But before now, they had been unable to find more complex molecular structures that were necessary for our planet's biology. Because of this, scientists have always assumed that the complicated chemistry of life must have originated in Earth's early oceans. Yet this new study calls that assumption into question.

"It's fascinating to consider that the most basic biochemical building blocks that led to life on Earth may well have had an extraterrestrial original," said Richard Mathias, co-author of the paper, in a press release.

While it's possible that these essential molecules were brought to Earth by a comet or possibly by meteorites, there's no definite answer. This experiment merely proves it as a possibility rather than a conclusive fact. Even so, the findings could lead to further research to discover where exactly life originated from.

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