One of the common problems faced by historians, geologists, archaeologists and anthropologists is the estimation of the age of particular specimens. Historians are interested in such things as the age of the Dead Sea Scrolls. Anthropologists are interested in the age of jaw bones which were found at Olduvai Gorge in Tanganyika. Archaeologists are interested in the date of Ptolemy’s sarcophagus. And geologists are interested in the age of the Earth. The answers for a long time evaded people. The best that geologists could do was come up with som sort of ordinal distinction: for example, they knew that the origin of the earth was an older event than the origin of the first rock and that the first rock was older than were the Rocky Mountains. Likewise, anthropologists could determine that Neanderthal man preceded Cro-Magnon, but still the exact age of these events …