Carbon dating super
But for all its social implications, carbon dating is strictly math and chemistry.Specifically, the math of ratios and the chemistry of carbon-14. When these tiny particles from deep space fly into Earth, they inevitably strike particles in our atmosphere.
Authorities can now use radiocarbon dating to determine exactly what year an elephant was killed, showing whether its tusks were legally obtained or not.Environment Canada used the new technique for the first time to convict Toronto-based Five Star Auctions and Appraisals, and company director Chun Al Jin, in February, the department said in a news release this week.The company and Jin were each hit with a penalty of $9,375, or a total of $18,750, and had to hand over two tusks to authorities.Labrecque and Uno also collaborated with the University of California, Irvine on the analysis, which costs about $1,000 US per tusk.Uno said this is the first time the technique was used in a true forensics case.(Tyrone Siu/Reuters) The company had claimed that the tusks were antiques.
But a radiocarbon analysis of the tusks showed that they likely both belonged to the same elephant, killed in 1978 plus or minus a year, said Guillaume Labrecque, of the radiochronology laboratory at Quebec's Laval University, who helped conduct the analysis. "The facts are right there." Radiocarbon dating is a technique commonly used in forensics and archeology to figure out the age of materials that come from plants or animals, such as bone or wood.
Willard Libby of the University of Chicago was the one who first realized the value of this punctual decay.
In the 1950s, he reasoned that if the atmosphere has a dependable ratio of regular carbon to carbon-14, that same ratio should be found in any living thing.
This collision causes a billiards-style reaction: Cosmic radiation knocks a neutron off a particle, which in turn smacks into nitrogen, which then knocks off a proton from the nitrogen.
When this chain reaction happens, the nitrogen drops down a spot in the periodic table and becomes carbon. Only about one in a trillion carbon atoms qualify as this variety.
But younger samples contain higher concentrations of carbon-14 because extra carbon-14 was added to the atmosphere by nuclear tests in the 1950s. The idea of analyzing elephant tusks with radiocarbon dating to identify illegal specimens was developed by Kevin Uno, a postdoctoral researcher at Columbia University in New York, who published a paper about it in 2013. So Uno asked Labrecque to use a chemical procedure to convert the material in the tusks to pure carbon dioxide.