A walk through time

Jeff Poling

The enormity of time. We homo sapiens sometimes have difficulty visualizing the span of months, let alone the span of millions of years. This is especially true for those of use who have difficulty visualizing any spatial or temporal distance (I like to call us "spatially challenged," which does not mean we simply take up valuable space, no matter what my mother may tell people). To aid in visualizing the enormous spans of time inherent in any discussion of paleontology, Dr. Dale Gnidovec, collections manager of Ohio State University's Orton Geological Museum, published an excellent visualization tool in his weekly column in the Columbus Dispatch.

Imagine you are taking a walk through time. Each step takes you back 1000 years. The following table shows you how far you would walk to witness certain important events in the history of Earth (Ma means mega-annums, or the number of million year periods from present to the time under consideration):

APPROX DIST	TIME	EVENT
2 steps	2000 yrs	the time of Christ
10 steps	10000 yrs	the final days of the mammoths, mastodons and saber-toothed cats at the close of the last great Pleistocene glaciation
30 miles, a walk from Columbus, Ohio, to Lancaster, Ohio	65 Ma	the K-T extinction that included the non-avian dinosaurs
100 miles, a walk from Columbus to Richmond, Indiana	225 Ma	the appearance of the first dinosaurs and mammals
120 miles, a walk from Columbus to Cincinnati, Ohio	245 Ma	the great Permian extinction that wiped out most life on earth, including the total eradication of the Trilobites
140 miles, a walk from Columbus to Toledo, Ohio	300 Ma	the appearance of the first reptiles
170 miles, a walk from Columbus to Charleston, West Virginia	360 Ma	the appearance of the first insects
200 miles, a walk from Columbus to Detroit, Michigan	435 Ma	the appearance of the first land plants
205 miles, a walk from Columbus to Louisville, Kentucky	440 Ma	the appearance of the first vertebrates
270 miles, a walk from Columbus to the Indiana/Illinois border	579 Ma	the appearance of the first animals with hard shells
280 miles, a walk from Columbus to Lansing, Michigan	600 Ma	the appearance of the first multicellular organisms
650 miles, a walk from Columbus to Albany, New York, or Charleston, South Carolina	1400 Ma	the appearance of the first nucleated cells
1800 miles, a walk from Columbus to Yellowstone in north-west Wyoming	3900 Ma	the formation of the oldest rocks known today
2100 miles, a walk from Columbus to Las Vegas, Nevada	4600 Ma	the formation of the Earth itself

1. Gnidovec, Dale. 1997. Eons' enormity hard to grasp. The Columbus Dispatch, 28 December, sec. B, 7.