Molecules vital to life have been detected in outer space and isolated in meteorites and comets. Some of this material that rained down on Earth may have jump-started biology. If so, these space seeds also may have planted a particular molecular orientation, or “handedness,” that spread to the world’s first creatures. New research is studying how this handedness could arise in space.
Amino acids, the building blocks of proteins, exist in two so-called “chiral” forms that are mirror reflections of each other, like a left and right hand. For some unknown reason, organisms use left-handed amino acids almost exclusively in making proteins (the other mirror image, while rare, is sometimes used in other processes).
“Outside of biology the ratio of these chiral forms is 50-50, so we want to understand the starting point of life’s preference for left-handed amino acids,” says Orlando Santos of NASA Ames Research Center.
Santos and his colleagues are designing a small satellite that would carry up biologically relevant molecules to see what effects space has on a sample’s handedness, and whether this could explain the origins of homochirality.
“Other researchers in this field have tried to reproduce space conditions in a lab,” Santos says. “But artificial systems are just that. We want to test the theories in a natural environment.”
The project is part of the Astrobiology Science and Technology Instrument Development and Mission Concept Studies. In a follow-up story, Astrobiology Magazine will profile another NASA-supported experiment that hopes to address how handedness in space might be delivered to the ground.