List of time periods

See also List of timelines for a list of timelines in general.

Table of contents

1 Cosmological time periods 2 Geologic time periods 3 Human time periods 3.1 Calendar systems 3.2 Human prehistorical periods 3.3 Human historical periods 3.4 Specialist human 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.

• The Big Bang

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).

Eon	Era	Period	Epoch
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 Paleocene, the Eocene, and the Oligocene are also collectively known as the Paleogene. The Miocene and the Pliocene are also collectively known as the Neogene.

These names differ across different countries; in particular, the division of the Carboniferous period into Mississippian and Pennsylvanian is purely a North American distinction.

Human time periods

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).

Calendar systems

• Common Era

Human prehistorical periods

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.

• the stone age - up to about 2500 BCE
  • Palaeolithic (Old stone age)
  • Mesolithic (Middle stone age)
  • Neolithic (New stone age)
• the bronze age - up to about 750 BCE
• the iron age - up to the historical periods

Human historical periods

• Antiquity (Ancient Greece, c:a 1000 BCE-, see Timeline of Ancient Greece)
• Pax Romana (Roman Empire, 96 - 180)
• Period of the Three Kingdoms (China, 220 - 280)
• Middle ages (Europe, 5th century - 14th century)
• Nara period (Japan, 709 - 795
• Period of Five Dynasties and Ten Kingdoms (China, 907 - 960)
• Sengoku period (Japan, 1478 - 1605)
• The Renaissance (Europe, 14th century - 16th century)
• Elizabethan period (United Kingdom, 1558 - 1603)

• Napoleonic Era, 1799-1815
• Victorian era (United Kingdom, 1837 - 1901)
• Edwardian period (United Kingdom, 1901 - 1910)
• Meiji era (Japan, 1868 - 1912)
• Cold War (United States and Russia, as well as Earth, 1945-1989)
• Post-communist period (Russia, after 1991)

Specialist human periods

There are many fields which have their own associated historical periods. These include:

Not yet in any particular order

• Climate
  • Medieval climate optimum
  • Little Ice Age
  • Global warming period
• Music
  • Renaissance
  • Baroque
  • Classical
  • Romantic
  • Modern
• Architecture - see also: architectural style
  • Gothic
  • Baroque

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