# 19 explain carbon 14 radioactive dating

Consider this—if a specimen is older than 50,000 years, it has been calculated, it would have such a small amount of C that for practical purposes it would show an ‘infinite’ radiocarbon age. Readers are referred to this article for other interesting conclusions about these dates.

In fact, the whole method is a giant ‘clock’ which seems to put a very young upper limit on the age of the atmosphere.

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!

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.

This means that he thought that C was entering the atmosphere as fast as it was leaving—calculations show that this should take place in about 30,000 years, and of course the Earth was much older than that, said the geologists.