Videos radiometric dating
Herschel’s “many thousand million years” and Lyle’s uniformitarianism shaped the cornerstone of Darwin’s theory.In the first paragraph of the Introduction in The Origin of Species, Darwin highlighted the centrality of Lyle’s and Herschel’s influence of on his theory: “to throw some light on the origin of species — that mystery of mysteries, as it has been called by one of our greatest philosophers.” Herschel had used this signature phrase, “that mystery of mysteries,” in a letter to Lyle endorsing his Principles of Geology.
Segment from A Science Odyssey: "Origins."Geologists have calculated the age of Earth at 4.6 billion years.
But for humans whose life span rarely reaches more than 100 years, how can we be so sure of that ancient date? Even the Greeks and Romans realized that layers of sediment in rock signified old age.
Accelerator mass spectrometry is not dependent upon the radioactive decay.
What you’re doing is measuring all of the carbon isotopes in the sample – the 12, 13 and 14 – the accelerator operates like a giant mass spectrometer.
As the uranium in rocks decays, it emits subatomic particles and turns into lead at a constant rate.