AMINO ACID DREAMS

AMINO ACIDS HOLD A SPECIAL fascination for astrochemists. They are considered one of the key classes of molecules that have to have been present before life could have arisen on Earth. All their constituent atoms are available many places in the universe besides Earth and, indeed, are known to be involved in extraterrestrial chemical reactions to form organic molecules that seem at least as complex as amino acids. Ifet the evidence is slim that amino acids exist anywhere in the universe except on Earth. Although slim, such evidence does exist. A few meteorites of a particularly carbonrich class known as carbonaceous chondrites contain amino acids among their carboncontaining molecules. The best studied of these, the famous Murchison meteorite, which fell in Australia in 1969, contains more than 70 different amino acids, including many of the 21 found in biological systems. So far, however, this small collection of unusual meteorites provides essentially all the hard evidence ...