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*waits for Stuart*
Quote from: DoctorBeaver on 21/07/2007 20:10:41*waits for Stuart*what are you trying to say [?]
Quote from: paul.fr on 21/07/2007 20:15:56Quote from: DoctorBeaver on 21/07/2007 20:10:41*waits for Stuart*what are you trying to say [?]Stuart works in forestry (cannot recollect his role right now, something to do with the European forestry commission, or something, if I recollect - it is somewhere mentioned on the site if you want to search for it).
You cannot carbon date a living organism because carbon dating merely dates an organism to the date when it was last alive, so an organism that is still living will have zero carbon date - you date the death of the organism, not its birth.
Quote from: another_someone on 22/07/2007 01:29:10You cannot carbon date a living organism because carbon dating merely dates an organism to the date when it was last alive, so an organism that is still living will have zero carbon date - you date the death of the organism, not its birth.I thought they had carbon dated a living Methuselah Tree !
Dr. Edmund Schulman, who discovered the Methuselah Tree in the 1950s, began his career in dendrochronology in 1932 at the University of Arizona's Laboratory of Tree Ring Research.
Currently, the oldest (acknowledged) living organism known is an individual of Pinus longaeva nicknamed "Methuselah" (after Methuselah, the longest-lived person in the Bible), located in the Ancient Bristlecone Pine Forest in the White Mountains of eastern California, and measured by core samples to be about 4,700 years old.
Carbon Dating is a controversial dating technique. The method is based on the rate of decay of the radioactive carbon isotope, Carbon-14, which is formed in the upper atmosphere through the effect of cosmic ray neutrons upon Nitrogen-14. The Carbon-14 is rapidly oxidized and enters the earth's organic life through photosynthesis (plants) and the food chain (animals). Carbon-14 also enters the earth's oceans in an atmospheric exchange and as dissolved carbonate. Plants and animals, which utilize carbon in organic functions and food chains, absorb Carbon-14 during their lifetimes. The assumption is that the earth-bound carbon exists in equilibrium with the Carbon-14 in the atmosphere, which means that the number of Carbon-14 atoms and non-radioactive carbon atoms stays approximately the same over time. As soon as a plant or animal dies, it ceases its carbon intake. Thereafter, there is no replenishment of radioactive Carbon-14, only decay. In 1949, a team of scientists led by Willard Libby of the University of Chicago discovered that this decay occurs at a constant rate. They found that after 5,568 years, half the Carbon-14 in a dead sample will decay, and after another 5,568 years, half of that remaining Carbon-14 will decay, and so on. Thus, the "half-life" for Carbon-14 was measured by Libby and his team at 5,568?0 years. After ten half-lives, there is a miniscule amount of radioactive carbon left in a sample, which means that the limit of the Carbon Dating method is reached at between 50,000 and 60,000 years.