Astronomers from Arecibo Observatory in Puerto Rico have found the organic molecules hydrogen cyanide and methanimine in Arp 220, a galaxy that lies about 250 million light years away. The discovery is noteworthy because the two molecules are among the basic ingredients of life. When methanimine and hydrogen cyanide are combined with water, the amino acid glycine is formed. This is the farthest ever that these molecules have been seen. The astronomers chose Arp 220, an ultra-luminous galaxy, because it seems to be forming new stars at a very high rate. They used the 305-metre diameter Arecibo radio telescope, the world's largest and most sensitive, to observe the galaxy at different frequencies. Different molecules have unique radio frequencies associated with them, much like human beings have unique fingerprints.

"The fact that we can observe these substances at such a vast distance means that there are huge amounts of them in Arp 220," said Emmanuel Momjian, a former Arecibo astronomer, now at the National Radio Astronomy Observatory in Socorro, New Mexico. "It is indeed very intriguing to find that the ingredients of life appear in large quantities where new stars and planets are born."