dating to work (and this applies to other dating methods as well), the carbon concentrations must not have not been altered throughout the specimen’s history. Common sense would say that this is an unreasonable assumption, especially if carbon dating can be used to ‘date’ objects up to 50,000 years old. This would mean that for 50,000 years, the specimen that is being dated must have remained in a closed system. If that weren’t enough, the scientists dating the specimen must also be able to make the determination of whether or not the system has remained closed. This is another assumption that is often made, but rarely addressed. In order for the dates from C14 to be accurate, the starting condition must be known. How do we know that the amount of C14 in an organism that lived say 5,000 years ago is the same amount that organisms have today?
There are some studies that suggest that the C14/C12 ratio in the atmosphere has been increasing since the 1950s. The bottom line is that if the C14/C12 ratio was smaller in the past and the assumption is made that it was the same as it is now, the specimen would appear much older than it really was.
Directly related to this, the earth’s magnetic field is rapidly decreasing. The average “intensity” (force turning a compass needle north) of the earth’s magnetic field has decreased by about 7% since its first careful measurement in 1829.
From a measure and projection of total field intensity for the location of 70°S, 12’E there has been a drop from about 50,000 nanoTeslas in 1922 to about 40,000 nanoTeslas in 2000. (GlRlJA RAJARAM, T. ARUN, WAY DHAR and A. G. PATIL. Indian Institute of Geomagnetism, Colaba, Mumbai 400 005, India). This indicates that the