The longest in geological time is an Eon eg. Archeozoic Eon . Edit: there is also the supereon, which is usually composed of 2-3 eons.
The longest subdivision in geologic time is the eon, which is further divided into eras. Eons represent the largest interval of time in the geologic time scale, such as the Phanerozoic eon which encompasses the last 541 million years.
The units of geologic time, from shortest to longest, are as follows: epoch, period, era, and eon. An epoch is the smallest unit, representing a subdivision of a period, which is a division of an era. Eras are then grouped into eons, the largest units of geologic time that encompass significant spans of Earth's history.
The longest subdivision of geologic time is called an super eon. Super eons make up a REALLY big chunk of time, around 2-4 billion years! There has only been 1 super eon the-Precambrian super eon. The hasn't been any new super eons due to the gap between Precambrian super eon & today-only a few hundred million years.
The order of units of geologic time from longest to shortest is: eon, era, period, epoch.
Joe Paterno
precambrian times
Precambrian Era.
About 50 to 100 million years.
In geologic time, the Hadean is the first EONof Earth's history, from it's formation 4.57 billion years ago to about 4 billion years ago. The Hadean is not an era, which is a smaller subdivision of geologic time.
The geologic time intervals from longest to shortest are eon, era, period, epoch, and age. This hierarchical sequence represents the largest divisions (eons) to the smallest subdivisions (ages) of Earth's history.
The longest segments of geologic time are eons, which are divided into eras, which are further divided into periods, epochs, and ages. The current eon, the Phanerozoic Eon, has been ongoing for approximately the last 542 million years.