Advent of Complex Life
NASA Astrobiology Institute
A Walk Through Geologic Time
How do we tell time?
For more information on Radiometric Dating and the creation of the Geologic Timescale:
Understanding Evolution's overview of the history of radiometric dating
Understanding Evolution's overview of using radiometric dating to tell how old a fossil is
And still more from Understanding Evolution
A more detailed and complex account of radioactive decay and radiometric dating
The website of International Commission on Stratigraphy, which decides on the official geologic time scale.
‹ Timeline Interactives
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