Radioisotope dating video
Using fossils as guides, they began to piece together a crude history of Earth, but it was an imperfect history.
As the uranium in rocks decays, it emits subatomic particles and turns into lead at a constant rate.Measuring the uranium-to-lead ratios in the oldest rocks on Earth gave scientists an estimated age of the planet of 4.6 billion years.Segment from A Science Odyssey: "Origins."Geologists have calculated the age of Earth at 4.6 billion years.Scientists discovered that rocks could be timepieces -- literally.
Many chemical elements in rock exist in a number of slightly different forms, known as isotopes.
Accepted Dating Methods Here we outline some dating methods, both absolute and relative, that are widely accepted and used by the scientific community.