Astrobiology Workshop, Macquarie University July 12-13 2001

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Molecular handedness and the origin of life

Jeremy Bailey (Anglo-Australian Observatory)

The homochirality of biological molecules (the use of only left handed or L-amino acids and right handed or D-sugars) has long been known to be an important characteristic of life. The discovery of an excess of L-amino acids in the Murchison and Murray meteorites suggests that homochirality reflects a bias that already existed in primordial solar system material before the origin of life. The action of circularly polarized light is the most likely source of such an asymmetry. Observations of circular polarization in star formation regions show that polarization due to dust scattering in reflection nebulae may be able to account for the chiral asymmetry. It may be that the suitability of a planet for life depends on the polarization environment in the region in which the star formed.