Radiometric dating is the method for establishing the age of objects by measuring the levels of radioisotopes in the sample. It decays to nitrogen 14 with a half life of 5730 years.
Carbon 14 is created by cosmic rays in the upper atmosphere.
Carbon-14 (C-14) dating of multiple samples of bone from 8 dinosaurs found in Texas, Alaska, Colorado, and Montana revealed that they are only 22,000 to 39,000 years old.Then, in the twentieth century, carbon dating found the bones to be about 22,000 years old — even though much of Britain was encased in ice and seemingly uninhabitable for part of that time.When Higham eventually got the bones, his team came up with a more likely scenario: they were closer to 33,000 years old and one of the earliest examples of ceremonial burial in Western Europe.Carbon generally forms four covalent bonds with other atoms in larger molecules.Atomic number 6; atomic weight 12.011; sublimation point above 3,500°C; boiling point 4,827°C; specific gravity of amorphous carbon 1.8 to 2.1, of diamond 3.15 to 3.53, of graphite 1.9 to 2.3; valence 2, 3, 4.
other isotope pairs cover intermediate time periods between the spans for carbon 14 and uranium.