Time Scale Vocabulary. Eon: the largest division of geologic time, comprising two or more eras . Era: a period of time marked by distinctive character, events, etc .
Eon: the largest division of geologic time, comprising two or more eras.
a period of time marked by distinctive character, events, etc.
Period: a rather large interval of time that is meaningful in the life of a person, in history, etc., because of its particular characteristics:
the beginning of a distinctive period in the history of anything:
~ 4.6 Billion Years Ago – collisions in the giant discs-haped cloud of material that also formed sun.
~ Gravity pulling gas and dust together made small planetesimals.
Objects collided repeatedly gradually getting bigger….building planets
~ Small to know metallic core
~ Could not hold atmosphere because there is no magnetic field.
~ With no atmosphere, the terrain is constantly being bombarded with solar winds - radiation
Comet and asteroid bombardment peppered all the planets.
Many craters developed on the moon.
These are not visible on the Earth because of tectonic plate movement erased all evidence over time……
But this is how water came to our planet.