Is carbon 14 dating correct
On April 26, 2007 this facility celebrated 25 years of operation, during which time it had processed over 75,000 radiocarbon measurements on objects ranging from the Dead Sea Scrolls to the Shroud of Turin.Their commercial rate (in 2008) is 5.00 per sample, which somewhat limits its accessibility to chronically under-funded archeological research projects.In this way, calibration tables have been developed that eliminate the discrepancy.Despite its usefulness, radiocarbon dating has a number of limitations.The theory behind radiocarbon dating is as follows: Why doesn't the carbon-14 in the air decay along with terrestrial carbon? The trick is that radioactive carbon-14 is continually replenished in a complex reaction that involves high-energy cosmic rays striking the upper atmosphere.
Radiocarbon dating is therefore limited to objects that are younger than 50,000 to 60,000 years or so.
This dramatically improves accuracy, and reduces the amount of carbon required from about 10 grams to only a few milligrams.
In recent years, dating methods based on cosmogenic isotopes other than carbon (such as beryllium-10 and chlorine-36) have been developed, which allow for the dating of a wider variety of objects over much longer time scales.
Conversely, contamination by newer plant matter carried by flowing water or intruding plant roots may result in a date that is much too young. The original technique was based on counting the number of individual radioactive decay events per unit of time, using a device similar to a Geiger counter.
Archaeologists are acutely aware of these and other potential difficulties, and take extreme care in the selection and handling of objects to be dated. In the 1970s a new technique was developed called Accelerator-based Mass Spectrometry (AMS), which counts the number of carbon-14 atoms directly.