The first three of these can be referred to collectively as the Precambrian supereon.
Some other planets and moons in the Solar System have sufficiently rigid structures to have preserved records of their own histories, for example, Venus, Mars and the Earth's Moon.
Dominantly fluid planets, such as the gas giants, do not preserve their history in a comparable manner.
This clock representation shows some of the major units of geological time and definitive events of Earth history.
The Hadean eon represents the time before fossil record of life on Earth; its upper boundary is now regarded as 4.0 Ga (billion years ago).
Other subdivisions reflect the evolution of life; the Archean and Proterozoic are both eons, the Palaeozoic, Mesozoic and Cenozoic are eras of the Phanerozoic eon.
The three million year Quaternary period, the time of recognizable humans, is too small to be visible at this scale.
For example, the lower Jurassic Series in chronostratigraphy corresponds to the early Jurassic Epoch in geochronology.
The adjectives are capitalized when the subdivision is formally recognized, and lower case when not; thus "early Miocene" but "Early Jurassic." Evidence from radiometric dating indicates that Earth is about 4.54 billion years old.
The following four timelines show the geologic time scale.
The first shows the entire time from the formation of the Earth to the present, but this gives little space for the most recent eon.
In the late 17th century Nicholas Steno (1638–1686) pronounced the principles underlying geologic (geological) time scales.