Scientists with the U.S. space agency NASA say they have found a compound in the dust from a comet that indicates life could exist beyond Earth.
Research published this week in the Journal Meteoritics and Planetary Science describes how NASA experts found the amino acid glycine in the dust and gas from a comet known as Wild 2.
NASA's Stardust spacecraft collected the samples when it crossed paths with the comet in 2004.
One of NASA's top astrobiologists, Carl Pilcher, said this discovery strengthens the argument that life in space may be common, rather than rare.
Amino acids are known as the building blocks of life. The 20 amino acids known to exist can be combined to form millions of different proteins.
Experts say they have developed tests that rule out the possibility that the amino acid originated on Earth. They said the glycine collected from the comet has an extraterrestrial carbon isotope signature that indicates it originated on the comet.