This list is under construction: the eventual aim is for it to be a compendium of names of eras and epochs in all fields of study
See periodization for a discussion of the tendency to try to fit history into non-overlapping periods.
Cosmological time periods
The cosmological timescale is the longest imaginable. It covers the entire extent of the universe - many billions of years. A short first period is measured in tiny fractions of seconds, but thereafter most things happen on the scale of billion years. It is used to consider events noticeable on a universal scale, such as the formation of matter, stars, and galaxies.
Geologic time periods
The geologic timescale covers the extent of the existence of Earth, from about 4600 million years ago to the present day. It is used to consider the formation and change of the Earth itself, and large-scale changes in the planet's inhabitants.
Dates are given as Millions of Years Ago (MYA).
|Precambrian (4600-544 MYA)||Hadean (4600-3800 MYA)|
|Archaean (3800-2500 MYA)|
|Proterozoic (2500-544 MYA)|
|Phanerozoic (544 MYA - now)||Paleozoic (544-245 MYA)||Cambrian (544-505 MYA)|
|Ordovician (505-440 MYA)|
|Silurian (440-410 MYA)|
|Devonian (410-360 MYA)|
|Carboniferous (360-286 MYA)||Mississippian (360-325 MYA)|
|Pennsylvanian (325-286 MYA)|
|Permian (286-245 MYA)|
|Mesozoic (245-65 MYA)||Triassic (245-208 MYA)|
|Jurassic (208-146 MYA)|
|Cretaceous (146-65 MYA)|
|Cenozoic (65 MYA - now)||Tertiary (65-1.8 MYA)||Paleocene (65-54 MYA)|
|Eocene (54-38 MYA)|
|Oligocene (38-23 MYA)|
|Miocene (23-5 MYA)|
|Pliocene (5-1.8 MYA)|
|Quaternary (1.8 MYA - now)||Pleistocene (1.8-0.01 MYA)|
|Holocene (0.01 MYA - now)|
The "human" timescale covers the time that humans have existed, usually taken to be from about 250,000 years ago - when Homo Sapiens[?] began to develop. It is broadly divided into prehistorical (before history began to be recorded) and historical periods (when written records began to be kept).
Human prehistory is usually divided by stages in development. However, different parts of the world entered these developmental stages at different times, so it is impossible to put firm dates on these periods.
There are many fields which have their own associated historical periods. These include:
Not yet in any particular order