This means that isotopes with a short half-life won’t work to date dinosaur bones. Some of the isotopes used for this purpose are uranium-238, uranium-235 and potassium-40, each of which has a half-life of more than a million years. Unfortunately, these elements don’t exist in dinosaur fossils themselves.

The rate of isotope decay is very consistent, and is not effected by environmental changes like heat, temperature, and pressure. This makes radiometric dating quite reliable.

C (the period of time after which half of a given sample will have decayed) is about 5,730 years, the oldest dates that can be reliably measured by this process date to approximately 50,000 years ago, although special preparation methods occasionally make accurate analysis of older samples possible.

Nitrogen-14 is one of two stable (non-radioactive) isotopes of the chemical element nitrogen, which makes about 99.636% of natural nitrogen. Nitrogen-14 is one of the very few stable nuclides with both an odd number of protons and of neutrons (seven each) and is the only one to make up a majority of its element.

Carbon-14 is a low energy beta emitter and even large amounts of this isotope pose little external dose hazard to persons exposed. The beta radiation barely penetrates the outer protective dead layer of the skin of the body.

Carbon-14, which is radioactive, is the isotope used in radiocarbon dating and radiolabeling. … medically important radioactive isotope is carbon-14, which is used in a breath test to detect the ulcer-causing bacteria Heliobacter pylori.

A by-product of cosmic rays The nucleus of carbon 14 contains 6 protons and 8 neutrons, as opposed to the 6 and 6 found in ordinary carbon 12. The imbalance makes carbon 14 a radioisotope with a half-life of 5,700 years, and an emitter of beta particles. This radioactive isotope of carbon is called radiocarbon.

Radiocarbon dating is therefore limited to objects that are younger than 50,000 to 60,000 years or so. (Since humans have only existed in the Americas for approximately 12,000 years, this is not a serious limitation to southwest archaeology.) Radiocarbon dating is also susceptible to contamination.