The molecules of life are large and complex. All things being equal, they can usually take one of two chemically identical forms that are distinguished by their “handedness”.
But here’s the thing: the molecular building blocks of life are either left or right-handed. Amino acids, for example, are without exception left-handed while RNA and DNA molecules consist of right-handed sugars. Their opposite-handed cousins simply do not exist in nature.
At least not on Earth. Now Noémie Globus at the University of California, Santa Cruz, and a couple of colleagues say that life on other planets must have similar properties and that we must devote more research to understanding how this handedness came about in the first place. The results could have important implications for where we look for life elsewhere in the universe.
Many chemists and evolutionary biologists have suggested that life’s handedness is simply an accident, that the gloopy ...
