However, rocks and other objects in nature do not give off such obvious clues about how long they have been around.
So, we rely on radiometric dating to calculate their ages.
Ever wonder how scientists concluded the age of the earth to be about 4.6 billion years old or how geologists determined the ages of caverns, rocks, volcanoes and the Himalayas? Well, scientists are able to answer all of these wondrous questions and more by use of a process called radiometric or radioactive dating.
Radioactive dating enables geologists to record the history of the earth and its events, such as the dinosaur era, within what they call the geologic time scale.
The methods work because radioactive elements are unstable, and they are always trying to move to a more stable state. This process by which an unstable atomic nucleus loses energy by releasing radiation is called radioactive decay.
The thing that makes this decay process so valuable for determining the age of an object is that each radioactive isotope decays at its own fixed rate, which is expressed in terms of its half-life.
It has become increasingly clear that these radiometric dating techniques agree with each other and as a whole, present a coherent picture in which the Earth was created a very long time ago.
This method is useful for igneous and metamorphic rocks, which cannot be dated by the stratigraphic correlation method used for sedimentary rocks. Some do not change with time and form stable isotopes (i.e.He was employed at Caltech's Division of Geological & Planetary Sciences at the time of writing the first edition.He is presently employed in the Space & Atmospheric Sciences Group at the Los Alamos National Laboratory.Radiometric dating--the process of determining the age of rocks from the decay of their radioactive elements--has been in widespread use for over half a century.There are over forty such techniques, each using a different radioactive element or a different way of measuring them.