Difference between revisions of "Radiocarbon dating"
(I'm sure we don't have to resort to enormous lies of omission with regards to scientific theories) |
|||
| Line 1: | Line 1: | ||
| − | Radiocarbon dating is a method for estimating the age of organic material by measuring the ratio of carbon-14 to carbon-12 present. This technique is based on the measured concentration of carbon-14 in the atmosphere, assuming relative stability, and uses the [[half-life]] of carbon-14, which is 5568 ± 30 years. | + | Radiocarbon dating is a method for estimating the age of organic material by measuring the ratio of carbon-14 to carbon-12 present. This technique is based on the measured concentration of carbon-14 in the atmosphere, assuming relative stability, and uses the [[half-life]] of carbon-14, which is 5730 ± 40 years, however a global standard half-life of 5568 ± 30 years is often employed. |
| − | + | Due to atmospheric disturbances over the history of the earth, the natural level and distribution of carbon-14 varies over time. For example, extremely recently in the earth's history, testing of [[nuclear bomb|nuclear weapons]] in the atmosphere has increased the concentration of carbon-14 in the Northern Hemisphere. To account for this, standard calibration curves are used to take account of chronological fluctuations, and results can be obtained which are rarely more than 700 years out. | |
| − | + | ||
| + | Other isotopes with longer half-lives can also be used to date objects- however, each method has its own drawbacks. For instance, the decay of potassium-40 is often used to complement the carbon-14 dating of [[dinosaur]] [[fossils]]. | ||
Revision as of 16:43, March 26, 2007
Radiocarbon dating is a method for estimating the age of organic material by measuring the ratio of carbon-14 to carbon-12 present. This technique is based on the measured concentration of carbon-14 in the atmosphere, assuming relative stability, and uses the half-life of carbon-14, which is 5730 ± 40 years, however a global standard half-life of 5568 ± 30 years is often employed.
Due to atmospheric disturbances over the history of the earth, the natural level and distribution of carbon-14 varies over time. For example, extremely recently in the earth's history, testing of nuclear weapons in the atmosphere has increased the concentration of carbon-14 in the Northern Hemisphere. To account for this, standard calibration curves are used to take account of chronological fluctuations, and results can be obtained which are rarely more than 700 years out.
Other isotopes with longer half-lives can also be used to date objects- however, each method has its own drawbacks. For instance, the decay of potassium-40 is often used to complement the carbon-14 dating of dinosaur fossils.