An international team of astronomers has found a possible explanation for why the amino acids in all living creatures are "left-handed", and why all sugars are right-handed - a mystery that has puzzled scientists for 150 years. Molecules with the same chemical composition can exist in two different forms, each the mirror image of the other. When molecules are created in the laboratory, left- and right-handed forms are created in equal number. Now astronomers using the Anglo-Australian Telescope have found evidence that left-handedness was imprinted in organic molecules in interstellar space before the formation of the Solar System (Jeremy Bailey et al 1998 Science 281 672).