The number 14 in carbon 14 dating
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.With a few important exceptions, living organisms keep all their amino acids in the “L” configuration.When an organism dies, control over the configuration of the amino acids ceases, and the ratio of D to L moves from a value near 0 towards an equilibrium value near 1, a process called racemization.Robert Service wrote in Science: The [soft tissue fossil] claims were met with howls of skepticism from biochemists and paleontologists who saw no way that fragile organic molecules could survive for tens of millions of years, and wondered whether her samples were contaminated with modern proteins.
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.
Here is a discussion of this and related finds by Brian Thomas, a creation oriented author: verified and extended protein identification in a duck-bill dinosaur that Mary Schweitzer’s team had described in 2009.
These two new finds join dozens of others published over the last half-century, but evolutionary scientists still have a hard time accepting that these fossils retain original biochemicals.
Thus, measuring the ratio of D to L in a sample enables one to estimate how long ago the specimen died.
This dating method is considered to be accurate for ages up to several hundred thousand years.