1. The Eras of Geologic Time
... . This vast span of time, called geologic time by earth scientists, is difficult to comprehend in the familiar time units of months and years, or even centuries. How then do scientists reckon geologic time, and why do they believe the Earth is so old? A great part of the secret of the Earth's age is locked up in its rocks, and our centuries-old search for ... the key led to the beginning and nourished the growth of geologic science. Geologic time is often discussed in two forms: • Relative time ("chronostratic ... from c. five billion to five hundred seventy million years ago is known...
- Word Count: 1841
- Approx Pages: 7
- Grade Level: Undergraduate