It is 4 billion years
The geological time scale organizes a long period of time.
The Precambrian.
Eon
Precambrian.
The Precambrian
Cenozoic Mesozoic Paleozoic Precambrian
The geologic time scale is divided into four eras: the Precambrian, Paleozoic, Mesozoic, and Cenozoic eras. Each era represents a distinct span of time in Earth's history with characteristic geological and biological features.
One million years on the geological time scale represents one million years of Earth's history. It is a unit of time used to measure and discuss long-term geological events and processes.
precambrian times
The geologic time scale is arranged from the time of Earth's formation through modern day. It is arranged into four eras. Those eras are Precambrian, Paleozoic, Mesozoic, and Cenozoic. Those eras are divided into periods in which the development of various life forms occurred.
These are put in order of older to newer. Precambrian, Paleozoic, Mesozoic, Cenozoic.
Precambrian time spans from the formation of the Earth, about 4.6 billion years ago, to the beginning of the Phanerozoic Eon, about 541 million years ago. It is the longest eon in Earth's history.