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  2. List of time periods - Wikipedia

    en.wikipedia.org/wiki/List_of_time_periods

    Classical antiquity – Broad term for a long period of cultural history centered on the Mediterranean Sea, comprising the interlocking civilizations of ancient Greece and ancient Rome, collectively known as the Greco-Roman world. It is the period in which Greek and Roman society flourished and wielded great influence throughout Europe, North ...

  3. Paleoproterozoic - Wikipedia

    en.wikipedia.org/wiki/Paleoproterozoic

    The Paleoproterozoic Era [4] (also spelled Palaeoproterozoic) is the first of the three sub-divisions of the Proterozoic eon, and also the longest era of the Earth's geological history, spanning from (2.5–1.6 Ga).

  4. Geologic time scale - Wikipedia

    en.wikipedia.org/wiki/Geologic_time_scale

    These units are arranged in a hierarchy: eon, era, period, epoch, subepoch, age, and subage. [14] Geochronology is the scientific branch of geology that aims to determine the age of rocks, fossils, and sediments either through absolute (e.g., radiometric dating ) or relative means (e.g., stratigraphic position , paleomagnetism , stable isotope ...

  5. Cretaceous - Wikipedia

    en.wikipedia.org/wiki/Cretaceous

    The Cretaceous (IPA: / k r ɪ ˈ t eɪ ʃ ə s / krih-TAY-shəss) [2] is a geological period that lasted from about 143.1 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 77 million years, it is the ninth and longest geological period of the entire Phanerozoic.

  6. Phanerozoic - Wikipedia

    en.wikipedia.org/wiki/Phanerozoic

    The Cretaceous is the Phanerozoic's longest period and the last period of the Mesozoic. It spans from 145 million to 66 million years ago, and is divided into two epochs: Early Cretaceous, and Late Cretaceous. [53] Tylosaurus, a type of large marine lizards known as mosasaurs

  7. List of decades, centuries, and millennia - Wikipedia

    en.wikipedia.org/wiki/List_of_decades,_centuries...

    List of years; Timelines of world history; List of timelines; Chronology; See calendar and list of calendars for other groupings of years.; See history, history by period, and periodization for different organizations of historical events.

  8. Era - Wikipedia

    en.wikipedia.org/wiki/Era

    An era is a span of time defined for the purposes of chronology or historiography, as in the regnal eras in the history of a given monarchy, a calendar era used for a given calendar, or the geological eras defined for the history of Earth. [1] Comparable terms are Epoch, age, period, saeculum, aeon (Greek aion) [2] and Sanskrit yuga. [3]

  9. Unit of time - Wikipedia

    en.wikipedia.org/wiki/Unit_of_time

    10 nanoseconds, also a casual term for a short period of time. microsecond: 10 −6 s: One millionth of a second. Symbol is μs millisecond: 10 −3 s: One thousandth of a second. Shortest time unit used on stopwatches. jiffy (electronics) ~ 10 −3 s: Used to measure the time between alternating power cycles. Also a casual term for a short ...