What are some events that all of us have had in our lives ... I like to use a meter stick and be very intentional with my spacing to model time as a scale. I also avoid using the far right of the ...

Prehistoric time line, geologic time scale, photos, facts, maps, and more from National Geographic. Humans have walked the Earth for 190,000 years, a mere blip in Earth's 4.5-billion-year history.

After all, they're more than 4,500 years old ... would appear less than a second before midnight. The geological time scale, established by scientists in the mid-19th century and agreed upon ...

We will provide a list of web sites with relevant information. The geologic time scale is divided into eons, eras, periods, epochs, and ages. Our activities, and the time scale for download above, ...