magazine has been continuously published since 1978, we are publishing some of the articles from the archives for historical interest, such as this.For teaching and sharing purposes, readers are advised to supplement these historic articles with more up-to-date ones suggested in the Related Articles below.It is assumed that the ratio has been constant for a very long time before the industrial revolution. (For on it hangs the whole validity of the system.) Why did W. Libby, the brilliant discoverer of this system, assume this?Obviously this only works for things which once contained carbon—it can’t be used to date rocks and minerals, for example. We obviously need to know this to be able to work out at what point the ‘clock’ began to tick.We’ve seen that it would have been the same as in the atmosphere at the time the specimen died. Do scientists assume that it was the same as it is now? It is well known that the industrial revolution, with its burning of huge masses of coal, etc.As soon as it dies, however, the C ration gets smaller.In other words, we have a ‘clock’ which starts ticking at the moment something dies.
An attempt to explain this very important method of dating and the way in which, when fully understood, it supports a ‘short’ timescale.
In fact, the whole method is a giant ‘clock’ which seems to put a very young upper limit on the age of the atmosphere.