March 12, 2012
Amino Acids In Meteorites Survived Extreme Temperatures
By studying samples from carbon-rich meteorites, scientists with NASA's Goddard Space Flight Center say they have discovered that the building blocks of life can be created and maintained in extreme heat, not just in cooler conditions as had previously been believed.
In a Friday press release, the U.S. space agency reports that experts from the Greenbelt, Maryland facility's Astrobiology Analytical Laboratory studied 14 samples and discovered "minerals that indicated they had experienced high temperatures -- in some cases, over 2,000 degrees Fahrenheit."
In those same samples, the scientists also discovered amino acids, commonly referred to as "the building blocks of proteins, used by life to speed up chemical reactions and build structures like hair, skin, and nails," they added.
During previous studies, Goddard researchers discovered those same building blocks in carbon-rich meteorites that contained minerals suggesting they had been formed by "a relatively low-temperature process involving water, aldehyde and ketone compounds, ammonia, and cyanide called 'Strecker-cyanohydrin synthesis.'"
The discovery, they say, suggests that the creation of amino acids and other substances essential for the formation of life may be able to be created in both hot and cold conditions, and that this potential versatility could increase the likelihood that life had been created elsewhere in the universe and not just on Earth.
"Although we've found amino acids in carbon-rich meteorites before, we weren't expecting to find them in these specific groups, since the high temperatures they experienced tend to destroy amino acids," Dr. Aaron Burton, a researcher in NASA's Postdoctoral Program working at the Goddard facility and the lead author of a paper detailing the team's findings, said in a statement.
That paper was published in the March 9 edition of the journal Meteoritics and Planetary Science, and in it, Burton and his colleagues surmise that the amino acids were created during a high-temperature process that occurred as their parent asteroids were cooling.
Their hypothesis claims that the process involved a series of chemical reactions involving hydrogen, carbon monoxide, and nitrogen known as the Fischer-Tropsch process, which typically occur in temperatures ranging from approximately 200 to 1,000 degrees Fahrenheit.
According to NASA, Fischer-Tropsch-type (FTT) reactions had been used during World War II to create gasoline from coal in order to combat a fuel shortage, and nowadays they are used in the creation of synthetic lubricants and other types of hydrocarbons.
"Water, which is two hydrogen atoms bound to an oxygen atom, in liquid form is considered a critical ingredient for life," Burton said. "However, with FTT reactions, all that's needed is hydrogen, carbon monoxide, and nitrogen as gases, which are all very common in space. With FTT reactions, you can begin making some prebiotic components of life very early, before you have asteroids or planets with liquid water."
"In almost all of the 14 meteorites we analyzed, we found that most of the amino acids had these straight chains, suggesting FTT reactions could have made them," he added.
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