Geologic Time MetaphorSuppose that all of geologic time were proportional to the length of...

Geologic Time Metaphor

Suppose that all of geologic time were proportional to the length of a football field (100 yards). Earth would have formed at the opposing team’s goal line (100 yards), and the present day would represent the home team’s goal line (0 yards).

Metaphor equation

Metaphor value = (years before present / age of Earth) × metaphor maximum

Example

Oldest fossil bacteria = 3,500 million years old

Age of Earth = 4,600 million years

Metaphor maximum = 100 yards

Metaphor value = (3,500,000,000/4,600,000,000) × 100 = 76 yards

Key metaphor dimensions

100 yards = 4,600 million years

10 yards = 460 million years

1 yard = 46 million years

1 foot = 15.3 million years

1 inch = 1.3 million years

Calculate the yardage of the extinction at the end of the Paleozoic era. Then fill in the blank cell in the table and label the following figure.

Develop your own metaphor for geologic time and describe it. Choose some of the most significant geologic events from the geologic timescale and convert them into your own metaphor equation.

Don’t try to be too detailed in your analysis. The intention here is to recognize the length of the geologic timescale and the relative positions of key events. Approximate lengths, distances, heights, widths, depths, sizes, time periods, and so on are okay as long as you recognize the relative proportions of the time intervals.