Carbon dating dinosaur bones wiki
In three half-lives the C14 concentration decreases by a factor of 8.
Twenty thousand years is 3.49 half-lives of C14 because 3.49 times 5730 is 20,000.
Perhaps there was less C14 produced in the past, which would imply that even the relatively young C14 dates are too old. The C14/C12 ratio of living things and organic matter on the surface of the earth is about the same as in the atmosphere because carbon is constantly exchanged between living things and the atmosphere.
After an organism dies, if it is buried and left undisturbed, the C14 in it gradually decays into nitrogen 14. Thus the ratio of C 14 to C12 in the remains of the organism gradually decreases with time.
If decay rates were faster in the past, then even the C14 dates could be too old.
Carbon 14 is an isotope of carbon with two extra neutrons in the nucleus. The rate at which this happens varies to some extent.
Other radioactive dating methods such as potassium/argon (K/Ar), rubidium/strontium (Rb/Sr), uranium/lead (U/Pb), thorium/lead (Th/Pb) and others that are based on decay of longer-lived isotopes often give ages in the millions or hundreds of millions of years for these fossils. However, in this talk I want to concentrate on reasons to believe the C14 dates are more accurate and that they give evidence that all life on earth is very young.In a 2015 paper in , her group reported isolating fragments of eight other proteins from fossils of dinosaurs and extinct birds, including hemoglobin in blood, the cytoskeletal protein actin, and histones that help package DNA. All amino acids except glycine (the simplest one) are optically active, having a stereocenter at their α-C atom.This means that the amino acid can have two different configurations, “D” or “L” which are mirror images of each other.By measuring the C14/C12 ratio, one can get an estimate of the age for the date of a once living object or a fossil, assuming that the production of C14 and its decay rate have been constant in the past.These estimates are roughly correct for historic time, that is, the past several thousand years.