Orion Nebula Gives Clues To Origin Of Life On Earth

What is intriguing is that amino acids in several meteorites show enantiomeric excesses of the same handedness as that seen in biological amino acids. Therefore, the process that produced the handedness of amino acids in the meteorites may provide clues to how homochirality developed in life forms on Earth. The larger question becomes how enantiomeric excesses can be produced and under what conditions.

How did life on Earth begin? One hypothesis is that terrestrial life began when organics were delivered from outer space during the early, heavy bombardment phase of Earth's development. We know that several meteorites (e.g., Murchison) have amino acids with properties similar to those seen in biological amino acids, the building blocks of life.

An international team of astronomers led by Fukue and Tamura of the National Astronomical Observatory of Japan conducted research on the properties of light in a massive star-forming region (BN/KL nebula) of the Orion Nebula and have investigated a process that may have played a role in the development of life on Earth.

The origin of what is technically called "biomolecular homochirality" is a longstanding mystery and an important one to solve, since it characterizes most life forms on Earth.

Chirality refers to the handedness of an image or phenomenon, which is not identical to the mirror image of its counterpart, much as the right and left hands are similar in structure but are opposites and thus not the same.

Homochirality means that a group of molecules exhibit the same handedness. Therefore, biomolecular homochirality indicates an organic group of molecules that are characterized by the same handedness. Terrestrial living material displays homochirality and consists almost exclusively of one enantiomer, L-amino acid, one of a pair of amino acids.

What is intriguing is that amino acids in several meteorites show enantiomeric excesses of the same handedness as that seen in biological amino acids. Therefore, the process that produced the handedness of amino acids in the meteorites may provide clues to how homochirality developed in life forms on Earth. The larger question becomes how enantiomeric excesses can be produced and under what conditions.