Errors carbon 14 dating
But in December, 1956, the National Geographical Society m conjunction with the Smithsonian Institution made it known that excavations at La Venta proved by radiocarbon that the classical period of the Meso-American civilizations (Olmec, Toltec, Maya, etc.) needs to be pushed back by a full thousand years and ascribed not to the 4th to 8th centuries of the Christian era but to the 8th to 4th centuries before that era.
With initial large margin of error and anything that did not square with expectation, judged as contaminated, the method appeared to work and was hailed as completely reliablejust as the atomic clock is reliableand this nobody doubted.
If such reversals were not instantaneous but required thousands of years, the atmosphere during that time would not be shielded from cosmic rays and substantially more of them would reach it.
However, the scientific literature of the last few decades did not contain any reference to a reversal observed on human artifacts like pottery though a paper by Manley in 1949 (Science News, Penguin Publication) told of the work of G.
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.
In Worlds in Collision I claimed that the time since the last glaciation needs to be drastically shortened: the figure considered valid in 1950, the year Worlds in Collision was published, was still Lyells of 100 years earlier, namely 35 thousand years. previously this maximum advance had been assumed to date from about 25,000 years ago, actually 35,000 if one looks up the literature of the time. found that, as I also claimed, another advance of ice took place only 3,500 years ago.