we often make reference to fossils to explain the past of living beings. Fossils are remnants (complete or partial) of living beings that have lived in the past (thousands, millions of years) or traces of their activity that are preserved generally in sedimentary rocks.
Have you ever wondered how science knows the age of a fossil? If you think of a fossil, surely the first thing that comes to your mind is a dinosaur bone or a petrified shell that you found in the forest, but a fossil is much more.
Fission track dating is based upon the fact that over geological time spontaneous fission of uranium-238 impurities produces minute sub- microscopic damage trails in the most insulating solids, both long period of time.
As the damage sites are permanent, a simple count of their number allows an age to be measured.
When subjected to external stimuli, mineral emits light due to these changes.