Miguel Sanz-Novo

In the dark, cold clouds where stars are born, dust grains are covered with an icy crust. Across this crust, like on a winter road, individual atoms wander slowly. Calculations show that it is precisely these wandering oxygen and nitrogen atoms that kick off the assembly of the HNSO molecule — a compound of hydrogen, nitrogen, sulfur, and oxygen.

Every molecule is like a set of building blocks: the same pieces can be assembled in different ways. Two assemblies with the same atoms but different geometry are called isomers. If one can be turned into the other by a simple rotation around a bond, they are conformers, like a bent arm versus a straight one.

In the heart of the Milky Way, in the cloud G+0.693, astronomers caught a sweet signal — emission lines of erythrulose, a simple sugar with four carbon atoms and four oxygen atoms.