Discover the basic component of life in comets

NASA scientists discovered glycine, the basic component of life, in Wild 2 comet specimens that were sent back by NASA's Stardust spacecraft.

Glycine is an amino acid used by living organisms to make proteins, and this is the first time an amino acid has been detected in comets, "said Dr. Jamie Elsila of NASA's Goddard Space Center at Greenbelt, Md. said. 'Our findings support the theory that some components of life are formed in space and taken to Earth by meteorites and comets'.

Elsila is the main author of the paper published in the journal Meteoritics and Planetary Science. This study will be presented at the meeting of the American Chemical Society at the Marriott Metro Center, Washington, DC, August 16.

Dr. Carl Pilcher, director of NASA's Space Biology Institute, which co-funded the study, said: 'Finding glycine in a comet is a testament to the idea that the basic components of life very popular in the universe, while reinforcing the argument that life in the universe is not a rare thing '.

Proteins are very important molecules of life, used in everything from structures such as hair to enzymes, catalysts that accelerate or control chemical reactions. Just like the 26 alphabets are arranged into unlimited combinations to make words, life uses 20 amino acids to form millions of different proteins.

The Stardust spaceship illustration begins its flight through gas and dust around comets Wild 2. The white area represents comets. The collected net is an object that has a tennis racket shape extending from the tail of the spacecraft. (Photo: NASA / JPL)

Stardust went through dense gas and dust surrounding Wild 2's frozen ice core on January 2, 2004. When the ship flew through this material, a special strainer filled the airgel - a new material like The sponge that 99% is empty space - gently obtained the comets and dust samples of comets. This mesh was placed in a casing, separated from the mother ship and landed on parachute on January 15, 2006. Since then, scientists worldwide have been analyzing these specimens to find understand the secret of comet formation and the history of the solar system.

Elsila said: 'We analyzed aluminum foil from small niches containing aerogels in the collection net. When gas molecules pass through the airgel, some stick on aluminum foil. We spent two years testing and developing the device to achieve sufficient accuracy and sensitivity to analyze these microscopic specimens. '

Previously, preliminary analysis at the Goddard laboratory detected glycine in aluminum foil and airgel samples. However, because glycine is used by underground life, the team was unable to eliminate the case of contamination from sources on Earth. 'It is possible that the glycine we found was derived from the fabrication and application of the Stardust spacecraft , ' Elsila said. This new study uses isotopic analysis of aluminum foil to eliminate that possibility.

Isotopes are versions of an element with different masses, for example, the most common carbon atom, Carbon 12, has six protons and six neutrons in the nucleus. However, the carbon 13 isotope is heavier because it can hold a neutron in the nucleus. The glycine molecule from space will tend to have more carbon 13 atoms than glycine from Earth. That is exactly what the research team found. 'We found that the Stardust-derived glycine has an extraterrestrial carbon isotope sign, which also means that it originated from comets,' Elsila explained.

The team includes Dr. Daniel Glavin and Dr. Jason Dworkin of NASA Goddard. Glavin added: 'Based on the results of aluminum foil and airgel, it is possible that all comets exposed to Stardust are covered by glycine formed in space'.

Stardust researcher, Professor Donald E. Brownlee of Washington University, Seattle, Wash, said: 'The detection of amino acids in comet specimens is really interesting and far-reaching. This is also a great victory that emphasizes the advancement of laboratory research on the outer space material '.

The research was funded by the NASA Stardust Specimen Analysis Program and NASA's Outer Space Biology Academy. NASA's reactive laboratory in Pasadena, Calif., Runs the Stardust spacecraft for the NASA Board of Science Spacecraft, Washington.