Paleontology. Reversals reveal pitfalls in spotting ancient and E.T. life.
Kerr
Richard A
RA
D002247:Carbon Isotopes; D018534:Earth, Planet; D018559:Exobiology; D052203:Ferrosoferric Oxide; D005580:Fossils; D019015:Geologic Sediments; D006108:Graphite; D007501:Iron; D007503:Iron Isotopes; D019369:Life; D018535:Mars; D019110:Meteoroids; D010087:Oxides; D010163:Paleontology; D013995:Time
D002247:Carbon Isotopes; D007503:Iron Isotopes; D010087:Oxides; D006108:Graphite; D007501:Iron; D052203:Ferrosoferric Oxide