New Extraterrestrial Sources Discovered for the Building Blocks of Life
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New Extraterrestrial Sources Discovered for the Building Blocks of Life
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Researchers have found a process that provides another piece to the puzzle of how life was kick-started on Earth, after a period of time between 4.5 and 3.8 billion years ago when the planet had been bombarded by comets and meteorites. The team from Imperial College London, the University of Kent and Lawrence Livermore National Laboratory discovered that when icy comets collide into a planet, amino acids can be produced. These essential building blocks are also produced if a rocky meteorite crashes into a planet with an icy surface.
“Our work shows that the basic building blocks of life can be assembled anywhere in the Solar System and perhaps beyond,” says Dr Zita Martins at Imperial College London. “However, the catch is that these building blocks need the right conditions in order for life to flourish. The 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.”
“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,” added Dr Mark Price, with the University of Kent, adds: 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 abundance of ice on the surfaces of Enceladus and Europa, which are moons orbiting Saturn and Jupiter respectively, could provide a perfect environment for the production of amino acids, when meteorites crash into their surface, say the researchers. Their work further underlines the importance of future space missions to these moons to search for signs of life.
The researchers discovered that when a comet impacts on a world it creates a shock wave that generates molecules that make up amino acids. The impact of the shock wave also generates heat, which then transforms these molecules into amino acids.
The team made their discovery by recreating the impact of a comet by firing projectiles through a large high speed gun. This gun, located at the University of Kent, uses compressed gas to propel projectiles at speeds of 7.15 kilometres per second into targets of ice mixtures, which have a similar composition to comets. The resulting impact created amino acids such as glycine and D-and L-alanine.
This past February, scientists used the National Science Foundation’s Green Bank Telescope (GBT) in West Virginia to study a giant cloud of gas some 25,000 light-years from Earth, near the center of our Milky Way Galaxy. The chemicals they found in that cloud include a molecule thought to be a precursor to a key component of DNA and another that may have a role in the formation of the amino acid alanine.
One of the newly-discovered molecules, called cyanomethanimine, is one step in the process that chemists believe produces adenine, one of the four nucleobases that form the “rungs” in the ladder-like structure of DNA. The other molecule, called ethanamine, is thought to play a role in forming alanine, one of the twenty amino acids in the genetic code.
“Finding these molecules in an interstellar gas cloud means that important building blocks for DNA and amino acids can ‘seed’ newly-formed planets with the chemical precursors for life,” said Anthony Remijan, of the National Radio Astronomy Observatory (NRAO).
In each case, the newly-discovered interstellar molecules are intermediate stages in multi-step chemical processes leading to the final biological molecule. Details of the processes remain unclear, but the discoveries give new insight on where these processes occur.
Previously, scientists thought such processes took place in the very tenuous gas between the stars. The new discoveries, however, suggest that the chemical formation sequences for these molecules occurred not in gas, but on the surfaces of ice grains in interstellar space.
“We need to do further experiments to better understand how these reactions work, but it could be that some of the first key steps toward biological chemicals occurred on tiny ice grains,” Remijan said.
The discoveries were made possible by new technology that speeds the process of identifying the “fingerprints” of cosmic chemicals. Each molecule has a specific set of rotational states that it can assume. When it changes from one state to another, a specific amount of energy is either emitted or absorbed, often as radio waves at specific frequencies that can be observed with the GBT.
New laboratory techniques have allowed astrochemists to measure the characteristic patterns of such radio frequencies for specific molecules. Armed with that information, they then can match that pattern with the data received by the telescope. Laboratories at the University of Virginia and the Harvard-Smithsonian Center for Astrophysics measured radio emission from cyanomethanimine and ethanamine, and the frequency patterns from those molecules then were matched to publicly-available data produced by a survey done with the GBT from 2008 to 2011.
The comet-impact research was published today in the journal Nature Geoscience.
The Daily Galaxy via Imperial College London and NRAO
Image credit: With thanks to http://newamericamedia.org/2011/08/in-case-you-missed-it—-nasa-finds-dna-in-space.php
New Extraterrestrial Sources Discovered for the Building Blocks of Life.
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As posted by Laura Tyco on http://2012indyinfo.com/
Also of interest from Laura Tyco: http://galacticlauratyco.blogspot.ie/
Source: http://2012indyinfo.com/2013/09/16/new-extraterrestrial-sources-discovered-for-the-building-blocks-of-life/
