Radiometric dating measures the decay of radioactive atoms to determine the age of a rock sample.
It is founded on unprovable assumptions such as 1) there has been no contamination and 2) the decay rate has remained constant.
A particular isotope of a particular element is called a nuclide. That is, at some point in time, an atom of such a nuclide will spontaneously change into a different nuclide by radioactive decay.
The decay may happen by emission of particles (usually electrons (beta decay), positrons or alpha particles) or by spontaneous nuclear fission, and electron capture.
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. 1979, 1986 © Harper Collins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 Cite This Source (ī'sə-tōp') One of two or more atoms that have the same atomic number (the same number of protons) but a different number of neutrons.
Carbon 12, the most common form of carbon, has six protons and six neutrons, whereas carbon 14 has six protons and eight neutrons.
However, to read any clock accurately we must know where the clock was set at the beginning.
Most people think that radioactive dating has proven the earth is billions of years old.
With the exception of hydrogen, elements found on Earth generally have the same number of protons and neutrons; heavier and lighter isotopes (with more or fewer neutrons) are often unstable and undergo radioactive decay.-suh-tohp)]In physics, different forms of the same element, with nuclei that have the same number of protons but different numbers of neutrons.By dating rocks of known ages which give highly inflated ages, geologists have shown this method can’t give reliable absolute ages.Many geologists claim that radiometric “clocks” show rocks to be millions of years old.The work of geologists is to tell the true story of Earth's history—more precisely, a story of Earth's history that is ever more true.A hundred years ago, we had little idea of the story's length—we had no good yardstick for time.