Theory and Experience

Abstract

We shall not discuss the philosophical contents of the concept “time”. Geochronology deals with functional time, providing a measurement procedure not of the time itself, but of values that are included in a certain law that gives time through other parameters. For instance, the time of passage by an airplane at some distance is calculated by division of the distance of passage into speed. The time of a liquid transfusion from one vessel to another is calculated using the rate of this transfusion and ratios of liquid volumes in the vessels. The Roman water clock is based on this principle. In geochronometry, isotopes of natural radioactive elements (uranium, thorium, rubidium etc.) are used and the time is calculated by the formula:

$$ t=\frac{1}{\lambda }\ln\!\left(\frac{D}{P}+1\right) $$

where λ – constant of radioactive transformation, P – number of parent particles, left at present, D – number of daughter particles.