Certain molecules do exist in two forms which are symmetrical mirror images of each other: they are known as chiral molecules. On Earth, the chiral molecules of life, especially amino acids and sugars, exist in only one form, either left-handed or right-handed. Why is it that life has initially chosen one form over the other? A consortium bringing together several French teams led by Louis d'Hendecourt, CNRS senior researcher at the Institut d'astrophysique spatiale (Université Paris-Sud 11 / CNRS), has for the first time obtained an excess of left-handed molecules (and then an excess of right-handedones) under conditions that reproduce...