Geologic Time - Metaphors [Athro, Limited]

Comprehending Geologic Time

The classic analogy for illustrating the relative durations of parts of the geologic time scale is the yardstick: Imagine that all the earth's history is laid out on a yardstick. Recall that the original measure of the yard was the distance from the king's nose to the tip of his fingers. If one yard represents all of geologic time, then one swipe of a nail file across the tip of king's finger will remove all of human history...

Imagine that the entire history of the earth is long.

The history of the earth would look like this:
Recorded Human History:
First Homo sapiens:

Major divisions of the geologic time scale

Time expressed as .

Eon	Era	Period	Events
Phanerozoic (-)	Cenozoic (-)	Neogene (-)
		Recent Pleistocene Pliocene Miocene	Modern Mass Extinction
		Paleogene (-)
		Oligocene Eocene Paleocene
	Mesozoic (-)	Cretaceous (-)	End Cretaceous Mass Extinction
		Jurassic (-)
		Triassic (-)
	Paleozoic (-)	Permian (-)	End Permian Mass Extinction
		Carboniferous (-) Pennsylvanian(US) Mississippian(US)
		Devonian (-)
		Silurian (-)	First invasions of the land
		Ordovician (-)	First Snails Time of the radiation of the Paleozoic fauna Dominated by Brachiopods and Crinoids
		Cambrian (-)	The time of the Trilobite dominated Cambrian fauna Begins with the Cambrian explosion The great radiation of multicellular animals
Proterozoic (-)	Neoproterozoic (-)		Ediacaran fauna Vendian Glaciation Crown eukariote radiation
	Mesoproterozoic (-)
	Paleoproterozoic (-)		Oxygen in atmosphere Formation of Continental Plates
Archean (-)			Origin of life
Hadean (-)			No surviving rocks on earth Ocean vaporizing meteor impacts Accretion of Earth

Geologic Time: Calculating Metaphors

You can use this calculator to create your own metaphor for geologic time. The history of the could be the the distance from your home to school - you can figure out where dinosaurs would be on the trip. Or the history of time could be the length of a class - and you could figure how much of the class you have to sit through before intelligence appears (if your class is 40 minutes long, human history begins in the last 1.5 milliseconds).