Radiometric dating 210pb
These long time periods are computed by measuring the ratio of daughter to parent substance in a rock and inferring an age based on this ratio.This age is computed under the assumption that the parent substance (say, uranium) gradually decays to the daughter substance (say, lead), so the higher the ratio of lead to uranium, the older the rock must be.The Uranium-238 radioisotope goes through 13 transitional stages before stabilizing into Lead-206 (U238 Pb206).In this instance, Uranium-238 is called the "parent" and Lead-206 is called the "daughter".Radiometric dating methods are the strongest direct evidence that geologists have for the age of the Earth.All these methods point to Earth being very, very old -- several billions of years old.This measurement is not dependent on time, in that a sample of U-238 that is one hundred years old will have the same half-life as a sample that is one thousand years old.
Radiometric dating is largely done on rock that has formed from solidified lava.As explained in the radioactivity node, there are three basic types of decay.The half-life of an isotope is defined as the time it takes for half of the radioactive ions to go through the process of decay.An isotope is one of two or more atoms which have the same number of protons in their nuclei, but a different number of neutrons.
Radioisotopes are unstable isotopes: they spontaneously decay (emitting radiation in the process -- thus making them radioactive).
They continue to decay going through various transitional states until they finally reach stability. It will spontaneously decay until it transitions into Lead-206 (Pb206).