Love-hungry teenagers and archaeologists agree: dating is hard.
But while the difficulties of single life may be intractable, the challenge of determining the age of prehistoric artifacts and fossils is greatly aided by measuring certain radioactive isotopes.
Paleontology seeks to map out how life evolved across geologic time.
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. 1979, 1986 © Harper Collins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 Cite This Source (rā'dē-ō-mět'rĭk) A method for determining the age of an object based on the concentration of a particular radioactive isotope contained within it.For inorganic materials, such as rocks containing the radioactive isotope rubidium, the amount of the isotope in the object is compared to the amount of the isotope's decay products (in this case strontium).If one knows how much of this radioactive material was present initially in the object (by determining how much of the material has decayed), and one knows the half-life of the material, one can deduce the age of the object.There's a small amount of radioactive carbon-14 in all living organisms.Though still heavily used, relative dating is now augmented by several modern dating techniques.
Radiocarbon dating involves determining the age of an ancient fossil or specimen by measuring its carbon-14 content.When they die no new carbon-14 is taken in by the dead organism.The carbon-14 it contained at the time of death decays over a long period of time.Strata are differentiated from each other by their different colors or compositions and are exposed in cliffs, quarries, and river banks.These rocks normally form relatively horizontal, parallel layers, with younger layers forming on top.Until this century, relative dating was the only technique for identifying the age of a truly ancient object.