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?Libby knew that C was entering and leaving the atmosphere (and hence the carbon cycle).
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.
Think of it like a teaspoon of cocoa mixed into a cake dough—after a while, the ‘ratio’ of cocoa to flour particles would be roughly the same no matter which part of the cake you sampled.
The fact that the C doesn’t matter in a living thing—because it is constantly exchanging carbon with its surroundings, the ‘mixture’ will be the same as in the atmosphere and in all living things.
Imagine the same tank, this time it is not yet full and the top tap is flowing more quickly than the bottom one is leaking out—this gives you a way of measuring how long ago the whole system was ‘switched on’ and it also tells you that that can't have been too long ago (see diagram above).
Libby knew that if these figures were correct, it would mean that the atmosphere was young, so he dismissed the results as being due to experimental error!
(We are not implying dishonesty here, merely showing how powerfully the evolutionary/uniformitarian concepts of Earth history influence great scientists to mould or discard evidence which appears to contradict that viewpoint.) What about modern measurements, using advanced technology such as satellites?
Unfortunately for the ‘old-Earth’ advocates, the studies of such renowned atmospheric physicists as Suess and Lingenfelter show that C is entering the system some 30-32% faster than it is leaving it.
Because Libby believed that the Earth was millions of years old, he assumed that there had been plenty of time for the system to be in equilibrium.