Explain radiometric dating fossils
For example, about 1.5 percent of a quantity of Uranium 238 will decay to lead every 100 million years.
By measuring the ratio of lead to uranium in a rock sample, its age can be determined.
Before then, the Bible had provided the only estimate for the age of the world: about 6,000 years, with Genesis as the history book.
Hutton's theories were short on evidence at first, but by 1830 most scientists concurred that Noah's ark was more allegory than reality as they documented geological layering.
Stratigraphy is the science of understanding the strata, or layers, that form the sedimentary record.
Strata are differentiated from each other by their different colors or compositions and are exposed in cliffs, quarries, and river banks.
A breakthrough came with the discovery of radioactivity at the beginning of the 1900s.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.For example, they are not sufficiently precise and reliable for estimating when the groups that feature in the Cambrian explosion first evolved, and estimates produced by different approaches to this method may vary as well.Together with stratigraphic principles, radiometric dating methods are used in geochronology to establish the geological time scale.