In recent years, forensic scientists have started to apply carbon-14 dating to cases in which law enforcement agencies hope to find out the age of a skeleton or other unidentified human remains.The new method is based on the fact that over the past 60 years, environmental levels of radiocarbon have been significantly perturbed by mid-20th-century episodes of above-ground nuclear weapons testing.At this moment, your body has a certain percentage of carbon-14 atoms in it, and all living plants and animals have the same percentage.Archaeologists have long used carbon-14 dating (also known as radiocarbon dating) to estimate the age of certain objects.20mg (i.e 2% of a gram) sample wrapped in aluminium foil and then zip lock is required.Cosmic rays enter the earth's atmosphere in large numbers every day.For more information on cosmic rays and half-life, as well as the process of radioactive decay, see How Nuclear Radiation Works.The carbon-14 atoms that cosmic rays create combine with oxygen to form carbon dioxide, which plants absorb naturally and incorporate into plant fibers by photosynthesis.
The researchers found that certain soft tissues — notably blood, nails and hair — had radiocarbon levels identical to the contemporary atmosphere.
When the neutron collides, a nitrogen-14 (seven protons, seven neutrons) atom turns into a carbon-14 atom (six protons, eight neutrons) and a hydrogen atom (one proton, zero neutrons).
Carbon-14 is radioactive, with a half-life of about 5,700 years.
The generally poor post-mortem preservation of soft tissues would be a limiting factor to this approach.
However, the researchers suggested that soft tissue radiocarbon content would be transferred to, and preserved in, the pupal cases of insects whose larvae feed on these tissues.
They measured carbon-14 levels in various tissues from 36 humans whose birth and death dates were known.