An epoch is typically smaller than an era or a period in geological or historical scales.
A period is smaller than an era in the geologic time scale. It is further subdivided into epochs and ages.
An era is a time period of indeterminate length, or, geologically speaking, a unit of time, smaller than aeons and greater than periods.
The next smaller division of geologic time after era is period. Periods are further divided into smaller units called epochs.
In geological time a period is smaller than an era but larger than a Epoch.The International Commission of Stratigraphic have divided the time as such from largest to smallest.Super-Eon - (SuperEonothem) (Not recognised by the ICS but unofficially recognised e.g. Precambrian time)Eon - (Eonothem)Era - (Erathem)Period - (System)Subperiod - (SubSystem)Epoch - (Series)Age - (Stage)Chron - (Chronozone) (Not recognised by the ICS but is unofficially recognised usually based on reversal of earths magnetic field)
On the geologic time scale, an era is longer than a period. There are 12 geologic eras in total and they are composed of geologic periods. For instance, the Mesozoic era is composed of the Triassic, Jurassic and Cretaceous periods.
No, a geologic era is a longer unit of time than a geologic period. Geologic eras are divided into periods, which are further subdivided into epochs. The hierarchy from largest to smallest is era, period, epoch.
A Period
An eon is the largest division of geologic time, lasting billions of years. An era is a subdivision of an eon, typically lasting hundreds of millions of years. A period is a smaller division of geologic time, lasting millions of years, and an epoch is an even smaller division of time, typically lasting tens of millions of years.
Eon, Era, and Epoch: APEX :D
Usually, an era refers to a specific time period, normally associated with the dates of an important event, while a period is often used to refer to events that share a characteristic, but do not have exact dates. The words are sometimes used interchangeably, and it isn't necessarily wrong to do so, since the usage is varied, but traditionally a period has been shorter than an era.
Smaller units of geologic time that make up eras include periods, epochs, and ages. These divisions help geologists to further classify and understand the history of the Earth's geological formations within each era.