If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?: Seventy-Five Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life

by Stephen Webb

the biochemistry of terrestrial organisms, and the biochemistry of any extraterrestrial organisms we can plausibly imagine, depends crucially on six elements: hydrogen (H), sulfur (S), phosphorus (P), oxygen (O), nitrogen (N) and carbon (C). In astronomical terminology, therefore, life depends upon hydrogen and the five metals SPONC.

O. SPONC