This led Libby to write in 1963: The data [in the Table] are separated into two groups Egyptian and non-Egyptian. The combined efforts of several researchers led them to believe that one of the conditions stipulated by Libby for a flawless functioning of his method was not historically sustained; it is claimed that the influx of cosmic rays varied with time.This separation was made because the whole Egyptian chronology is interlocking and subject to possible systematic errors . . Also, Egyptian historical dates beyond 4000 years ago may be somewhat too old, perhaps 5 centuries too old at 5000 years ago. Yet, since this influx comes from many sources, the sun being only one of them, sunspot activity could be related to the variation only in a very limited degree.The correctness of the method depends greatly on the condition that in the last 40 or 50 thousand years the quantity of water in the hydrosphere (and carbon diluted in it) has not substantially changed. The method depends also on the condition that during the same period of time the influx of cosmic rays or energy particles coming from the stars and the sun has not suffered substantial variations.
Therefore the claim was made that the magnetosphere around the earth, discovered in 1958, suffered occasional weakening, thus allowing more cosmic rays to pass it and to hit the nitrogen atoms in the upper atmosphere, changing them to radiocarbon.
It was further claimed that the magnetic field of the earth might have reversed its polarity in the last 40 thousand years, a phenomenon known to have happened in geological epochs.
Continue reading Carbon-14 dating is the center of debate as it pertains to dating from the Iron Age period. Other opinions place the transition somewhere between the two—in about 950 B. The dates must be calibrated and are based on unprovable assumptions about the past.
This off-site article illustrates the general propensity of scholars to reject the more substantial and reliable methods of pottery dating and other historical synchronisms involving ancient records and eyewitness testimony. According to the low chronology, the transition to Iron Age IIa occurred around 920–900 B. The same problem is found in dating Jericho and other sites in the ANE in the Second Millenium B.
Offering in 1952 his new radiocarbon method for calculating the age of organic material (the time interval since the plant or the animal died), W. Libby clearly saw the limitations of the method and the conditions under which his theoretical figures would be valid: A.
Of the three reservoirs of radiocarbon on earththe atmosphere, the biosphere, and the hydrosphere, the richest is the lastthe oceans with the seas.
And certainly the building of tree ladders, or carrying on the count from one tree to another may cause erroneous conclusions.
One and the same year may be dry in South California and wet in the northern part of the state.
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.