Radiocarbon dating and the atomic bomb
In spite of assurances given to Velikovsky that the results would be published, they never saw the light of day.” has drawn attention to a number of difficulties that have arisen with radiocarbon dating and the implications for Egyptology.A warning about future difficulties with the reliability of radiocarbon dating has been issued by Heather Graven, a climate-physics researcher at Imperial College London.Later this was revised to 5730±40 years and is known as the Cambridge half-life.The initial theory was based on the assumption that Carbon-14 was being produced at a constant rate.Local events can also have a dramatic effect on measurements; for example, the Tunguska explosion left the soil there so enriched with Carbon-14 that it gives a date in the future (1)!Emilio Spedicato has also pointed out that Carbon-14 can be created in the atmosphere by any cometary or asteroidal impact and so alter the assumed constant ratio of C12 to C14.
First, it was noticed that, when radiocarbon dated, wood grown in the 20th century appears more ancient than wood grown in the 19th century.
Suess explained the phenomenon by the fact that the increased industrial use of fossil carbon in coal and in oil changed the ratio between the dead carbon C12 and the C14 (radiocarbon) in the atmosphere and therefore also in the biosphere.
In centuries to come a body of a man or animal who lived and died in the 20th century would appear paradoxically of greater age since death than the body of a man or animal of the 19th century, and if the process of industrial use of fossil, therefore dead, carbon continues to increase, as it is expected will be the case, the paradox will continue into the forthcoming centuries.” that ‘recent evidence suggests that that the level of Carbon 14 in the atmosphere may have decreased permanently around 3,500 years ago due to changes in the earth’s magnetic field.’ This has resulted in dates around that period being up to 500 year out.
Since many other episodes of a lesser or greater intensity have probably occurred, a growing shadow is being cast over the reliability of radiocarbon dating that may only dissipated by further studies.
Clearly, further complex recalibration is not to be ruled out, as it is highly unlikely that this eight century event was the only such occurrence.