Radiometric dating (often called radioactive dating) is a technique used to date materials such as rocks or carbon, usually based on a comparison between the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates.The use of radiometric dating was first published in 1907 by Bertram Boltwood and is now the principal source of information about the absolute age of rocks and other geological features, including the age of the Earth itself, and can be used to date a wide range of natural and man-made materials.I found several good sources, but none that seemed both complete enough to stand alone and simple enough for a What is radiometric dating?Simply stated, radiometric dating is a way of determining the age of a sample of material using the decay rates of radio-active nuclides to provide a 'clock.' It relies on three basic rules, plus a couple of critical assumptions.Protons and neutrons together are called nucleons, meaning particles that can appear in the atomic nucleus.A nuclide of an element, also called an isotope of an element, is an atom of that element that has a specific number of nucleons.
All these methods point to Earth being very, very old -- several billions of years old.The thin, dark part of each ring represents slow autumn and winter growth.Several other processes result in the accumulation of distinct yearly layers that can be used for dating.Geologists have carefully sorted out more than 100,000 microscopic Jack Hills zircons that date back to Earth's early epochs, from 3 billion to nearly 4.4 billion years ago.(The planet is 4.54 billion years old.) The crystals contain microscopic inclusions, such as gas bubbles, that provide a unique window into conditions on Earth as life arose and the first continents formed.