According to experts, dating with radioactive carbon is the most popular method by far. This method involves measuring the amount of carbon-14, a radioactive carbon isotope. Carbon-14 is everywhere in the environment.

While the most common form of carbon has six neutrons, carbon-14 has two more. That makes the isotope much heavier and less stable than the most common form of carbon. So, after thousands of years, carbon-14 finally breaks down. One of its neutrons splits into a proton and an electron. While the electron is released, the proton remains part of the atom. With one less neutron and one more proton, this isotope decays into nitrogen.

When organisms di‌e, they stop absorbing carbon-14, and the remaining amount in their body begins slow radioactive decay. Scientists know the time it takes for half a certain amount of carbon-14 to break down is called the half-life. That allows them to measure the age of a piece of organic matter, whether it’s animal skin or skeleton, ash or tree rings.

The half-life of carbon-14 is 5,730 years, ideal for scientists wanting to study 50,000 years of history. That includes the really interesting part of human history, the origins of agriculture, the growth of civilizations.

Older objects have lost more than 99% of their carbon-14, leaving too little to detect, says Brendan Culleton, an as‌sistant research professor at the Pennsylvania State University’s Radioactive Carbon Laboratory. For older objects, the scientists do not use carbon-14 as a measure of age. Instead, they often turn to radioactive isotopes of other elements in the environment.

For the world’s oldest objects, uranium - thorium - lead dating is the most useful method.

"We use it to date the Earth. While radioactive carbon dating is only useful for materials that were once alive, we can use it," the scientists said. Using the Uranium - Thorium - Lead dating method to measure the age of objects such as rocks In this method, it is possible to measure the quantities of a variety of radioactive isotopes, all of which decay into lead. These separate chains of decay begin with the decomposition of uranium-238, uranium-235 and thorium-232.

"Uranium and thorium are large isotopes that flare up in her seams," said Tammy Rittenour, a geologist at Utah State University.

These "parent isotopes" break down into a series of different radioactive isotopes before they turn into lead, each with a half-life span ranging from a few days to billions of years. Of radioactive carbon, the scientists calculate the ratios of these isotopes, compare them to their respective half-lives Using this method, scientists can determine the age of the rocks. The oldest ever discovered is a 4.4 billion year old zircon crystal found in Australia.

Finally, a method of dating tells scientists not how old the object is, but when it was last exposed to heat or sunlight. This method, called luminescent dating, is favored by geologists when studying the changes in landscapes over the past million years. They can use it to discover when a glacier forms or recedes, deposits rock in a valley or when a flood spills silt onto a river basin.

When minerals in rocks and sediments are buried, they are exposed to radiation emitted by the sediments surrounding them. This radiation pushes electrons out of their atoms. Some electrons return to the atom, but others are trapped in holes or elsewhere in the dense network of atoms around them.

It takes a second exposure to heat or sunlight to knock these electrons back to their original positions. That’s exactly what scientists do. They expose a sample to light and when the electrons fall back at the atom, they emit heat and light, or a luminescent signal.

The longer the object is buried, the more radiation it is exposed to. In essence, buried objects that have been exposed to a lot of radiation for a long time will have a large number of electrons being ejected from their position, which together emit a brilliant light when they return to the original. death of them. Therefore, the amount of luminescent signals tells scientists how long the object was buried.

Dating objects are not only important to understanding the world’s age and how ancient humans lived. Forensic scientists also use it to solve problems related to crime or cases. Radiocarbon dating can even tell us how long a fine wine or whiskey has been aged, whether it has been tampered with.