This week GeoLog will begin a trip through time, exploring the physical and biological changes on Earth through the more than four-and-a-half billion years of its history, as told through the rocks and fossils that are the physical evidence of these changes. But first, a few words about our frame of reference:
Geologists tend to use numbers like 4.6 billion without a second thought. In fact, the scope of what we call geologic time is ENORMOUS and extremely hard to comprehend, especially for those of us who spend our days counting seconds, minutes and hours.
After all, our own life spans are on the order of 10s to one hundred years; known civilization goes back only thousands of years, and there were no modern humans around millions of years ago.
Our ability to comprehend the vast eras of geologic time is severely challenged by the remoteness and scope of these events.
Links for some help in visualizing these large numbers:
This site measures millions and billions in pennies, and the image of one billion pennies (above) is from here.
Teachers can find an exercise for class use on big numbers here, and the geologic time scale here and here.
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