Carbon-14 has a relatively short half-life of 5730 years, meaning that the amount of carbon-14 in a sample is halved over the course of 5730 years due to radioactive decay.By about ten half-lives, or 58,000 years, the amount of carbon-14 left in the fossil is very little- about 1/1000 of the original number of carbon-14 atoms in the fossil.They observed that every rock formation, no matter how ancient, appeared to be formed from still older rocks.
Plants take in atmospheric carbon dioxide by photosynthesis, and are ingested by animals.
So, every living thing is constantly exchanging carbon-14 with its environment as long as it lives. The carbon in its body will remain until it decomposes or fossilizes.
By the early 1960s, most of the major radiometric dating techniques now in use had been tested and their general limitations were known.
No technique, of course, is ever completely perfected and refinement continues to this day, but for more than two decades radiometric dating methods have been used to measure reliably the ages of rocks, the Earth, meteorites, and, since 1969, the Moon.
There are a number of long-lived radioactive isotopes used in radiometric dating, and a variety of ways they are used to determine the ages of rocks, minerals, and organic materials.
Some of the isotopic parents, end-product daughters, and half-lives involved are listed in Table 1.However, it is also used to determine ages of rocks, plants, trees, etc. When the sun’s rays reach them, a few of these particles turn into carbon 14 (a radioactive carbon).The highest rate of carbon-14 production takes place at altitudes of 9 to 15 km (30,000 to 50,000 ft).James Hutton, a physician-farmer and one of the founders of the science of geology, wrote in 1788, “The result, therefore, of our present inquiry is, that we find no vestige of a beginning, — no prospect of an end.” Although this may now sound like an overstatement, it nicely expresses the tremendous intellectual leap required when geologic time was finally and forever severed from the artificial limits imposed by the length of the human lifetime.By the mid- to late 1800s, geologists, physicists, and chemists were searching for ways to quantify the age of the Earth.Some chemical elements have more than one type of atom. Carbon has two stable, nonradioactive isotopes: carbon-12 (12C), and carbon-13 (13C).