Life On Earth May Be Extraterrestrial

NASA said Monday that a comet scoured by its Stardust spacecraft was found to be carrying an amino acid that is an essential building block for organic life. It's the first time such an amino acid, glycine in this case, has been discovered on a comet.

"Our discovery supports the theory that some of life's ingredients formed in space and were delivered to Earth long ago by meteorite and comet impacts," said James Elsila, of NASA's Goddard Space Flight Center in Greenbelt, Maryland.

Stardust collected samples from the comet Wild 2 by flying through its debris trail in January of 2004. It took researchers two years just to develop techniques to accurately analyze the tiny samples. Officials said NASA's findings reinforce the view that Earth is not the only planet in the universe that supports organic life.

"The discovery of glycine in a comet supports the idea that the fundamental building blocks of life are prevalent in space, and strengthens the argument that life in the universe may be common rather than rare," said Carl Pilcher, director of NASA's Astrobiology Institute.

Organic life in any known form is comprised of proteins that are derived from varying combinations of 20 different amino acids. NASA's findings suggest comets can act like interstellar bees, disseminating life throughout the universe by distributing amino assets to planets like the insects spread pollen.

"We discovered that the Stardust-returned glycine has an extraterrestrial carbon isotope signature, indicating that it originated on the comet," said Elsila.

NASA presented its research results this week at a meeting of the American Chemical Society in Washington, DC.