It’s now official: Life on earth began on space, says a new study on meteorite strengthening evidence that biological raw ingredients were carried to the planet in lumps of asteroid rocks.
The Nasa research has suggested that a wider range of asteroids were capable of creating the kind of amino acids used by life on earth.
The molecules come in two mirror-image varieties, known as left and right-handed. But only left-handed amino acids are found in nature. In March 2009, researchers at Nasa’s Goddard Space Flight Centre in Greenbelt found an excess of the left-handed form of the amino acid isovaline in samples of meteorites that came from carbon-rich asteroids.
The discovery suggested that perhaps left-handed life got its start in space, where conditions in asteroids favoured the creation of left-handed amino acids. Meteorite impacts could have supplied this material to earth.
“This tells us our initial discovery wasn’t a fluke; that there really was something going on in the asteroids where these meteorites came from that favours the creation of left-handed amino acids,” Daniel Glavin of Nasa was quoted as saying by Daily Mail.
The scientists believe that early in its history, earth was bombarded with meteorites containing left-handed amino acids. The bias towards left-handedness would have continued as the material was incorporated into emerging life.
Evidence suggests that the presence of liquid water amplifies levels of left-handed isovaline (L-isovaline) in asteroids.