The Scale of Geologic Time

The concept of geologic time is one of the most important intellectual developments in scientific thought. Understanding geology and its processes is inextricably linked to time. And yet, geologic time is extremely difficult to grasp simply because of its vastness.

This video explains geologic time using three different approaches. The first portion shows two photographs of the Green River in Utah that were taken 97 years apart in the same position and orientation. The photos show very little change in the landscape, indicative of the extremely slow rates of geologic processes, i. e. longer than one human life.

The second approach uses a calendar and the third approach uses a yardstick to illustrate the length of geologic time by indicating where significant geologic events would occur respectively, by the month and date or within the length of the yard stick.