User:Universal Life/History of the Universe

This page outlines major and significant events known to mankind in the history of the universe, in a chronological order.[a]

Major Concepts edit

History edit

History has multiple definitions. However most simply it can be defined as the study of the past, especially of humans.[1] History is a record of past events, as well as the branch of knowledge that studies it. Historians are the scholars who write about history. Events occurring prior to written record are considered prehistory.

Particular studies and fields
  • Ancient history : the study from the beginning of human history until the Early Middle Ages.
  • Art History: the study of changes in and social context of art.
  • Big History: study of history on a large scale across long time frames and epochs through a multi-disciplinary approach.
  • Chronology: science of localising historical events in time.
  • Comparative history: historical analysis of social and cultural entities not confined to national boundaries.
  • Contemporary history: the study of historical events that are immediately relevant to the present time.
  • Cultural history: the study of culture in the past.
  • Digital History: the use of computing technologies to produce digital scholarship.
  • Economic History: the study of economies in the past.
  • Futurology: study of the future: researches the medium to long-term future of societies and of the physical world.
  • Intellectual history: the study of ideas in the context of the cultures that produced them and their development over time.
  • Maritime history: the study of maritime transport and all the connected subjects.
  • Modern history : the study of the Modern Times, the era after the Middle Ages.
  • Military History: the study of warfare and wars in history and what is sometimes considered to be a sub-branch of military history, Naval History.
  • Natural history: the study of the development of the cosmos, the Earth, biology and interactions thereof.
  • Palaeography: study of ancient texts.
  • People's history: historical work from the perspective of common people.
  • Political history: the study of politics in the past.
  • Psychohistory: study of the psychological motivations of historical events.
  • Social History: the study of the process of social change throughout history.
  • Universal history: basic to the Western tradition of historiography.
  • Women's history: the history of female human beings. Gender history is related and covers the perspective of gender.
  • World History: the study of history from a global perspective.
 
History by Frederick Dielman (1896)

The word "history" ultimately derives from the old Vedic Sanskrit root verb "vid", meaning "to know". The large body of texts called the Vedas and the concept of Vidya comes from vid. The word veda means "knowledge" in Sanskrit, while vidya means "learning" or "correct knowledge". The Turkish root verb bil (know) has also probably derived from vid. This very vid (which in some point also came to mean "to see") is at the root of many English words such as advice, clairvoyant, envy, evident, history, idea, interview, review, revise, story, supervise, twit, video, view, visa, visage, visible, vision, visit, vista, visual, voyeur, wise and wit[2] Later in Vedic Sanskrit, the verb jiṋá (jñā) was created for the different senses or uses of "knowing" which is the root of the English verb to "know".[3]

The Ancient Vedic Sanskrit root verb vid- "to know", passed to the Ancient Greek as ϝίδ- (wid-) and together with the suffix -τωρ ("-tōr": equivalent to the English suffix -er, "the one who") it gave ϝίδτωρ (wídtōr): "the one who knows, knower, expert". This ϝίδτωρ (wídtōr) developed in time into ἵστωρ (hístōr) in Ancient Greek and it also developed the senses of "wise man" and "judge". From ἵστωρ (hístōr) came the verb ἱστορέω (historéō), that's "I learn through research, I inquire".[2]

The Ancient Greek noun ἱστορία (historíā) came from this verb ἱστορέω (historéō) and meant "learning through research", "inquiry", "knowledge acquired through inquiry" and later also "written account of such inquiries", "narrative", "history".[4] The Romans took the word from the Greeks only in the latter sense, so in Latin historia meant "narrative of past events", "account", "tale" and "story". The English words history, story and storey all derive from this Latin "historia".[2]

The Latin historia became estorie and later estoire in Old French. Estoire (as well as modern French histoire) means both:

  1. Record or chronicle of past events and
  2. Story

The English language took the word from the French at the end of the 14th century. In the Middle English of that time, there was still no distinction between the senses of "history" and "story", which were both the same word. Later on story became a different word and history only meant "record of past events" around 1500s. It was only in 1842 that it developed the sense of a scientific discipline. In most modern Romance and Germanic languages such as French, German and Spanish, there's no distinction between the senses of "history" and "story".[2]

Historical means "pertaining to history, to what happened in the past", while historic means "having importance or significance in history" and also "having a long history". In older English, historic was synonymous with historical.

While the concept of historíā (ἱστορία) which developed in Ancient Greece had few senses, for similar concepts in Ancient India, there were four terms: kávya (kāvya), puráńa (purāṇa), itikathá (itikathā) and itihása (itihāsa). These are the four parts of the Sanskrit literature.[5]

  1. Kávya is a "poetic verse" or a "story" narrated in a lucid way, in a very systematic way. It may be factual or not. It may be educative or not.
  2. Puráńa (mythology) is a "fictive tale or story", composed with educative purposes.
  3. Itikathá is a "chronological record of events". It's history in the modern sense. Itivrtta (itivṛtta), purávrtta (purāvṛtta) and purákathá (purākathā) are synonyms with itikathá.
  4. Itihása has no synonym in English. It has been defined as "that part of itikathá (history) which has educative value and whose study imparts moral education and leads to human welfare". It focuses on cultural history, social history and people's history.
"Human beings should not be compared to individual flowers, but to an entire flower garden. A flower garden is made up of innumerable varieties of flowers, each with its own fragrance and colours. Human history is like this: the beauty of history lies in its kaleidoscopic variations in spatial, temporal and personal factors. We cannot afford to spoil its characteristics; nor can we forcibly impose a particular type of history on a certain community.
"Every individual or community will advance by virtue of its own inner vitality and assist in the collective fulfilment of the entire humanity. This is the true spirit of history. While writing history we will have to consider the various spheres of human life and ensure that proper directions are given for the development of each sphere. For instance, history should focus upon the prevalent educational system, cultural standards, thoughts and ideas, dress, the social condition of women, the role of women in the social and economic spheres, and the socio-economic conditions of the weak and backward communities of the society of a particular age, etc. If any of these aspects are omitted while writing history, it will be incomplete."[6]

Historiography refers to both the study of the methodology of historians and the development of history as a discipline, and also to a body of historical work on a particular subject.

Periodisation is the attempt to categorise universal history or divide time into named blocks. Prehistory is traditionally divided (according to archaeology) into three ages: stone age, bronze age and iron age. However the dates for each age and their subdivisions vary greatly from region to region.

The stone age (Turkish: taş devri) is divided into the palaeolithic (yontma taş devri), mesolithic and neolithic (cilalı taş devri). Bronze Age (tunç devri) is sometimes divided into two: silver age and bronze age.

History is also usually divided into three: Ancient history (3600 BC - 500 CE), Post-classical era (500 - 1500) and Modern history (1500 - Present). Ancient history includes the bronze age (app. 3600 BC - 1000 BC) and the iron age (1000 BC - 500 CE) and it ends with the fall of several significant empires, such as the Western Roman Empire in the Mediterranean, the Han Dynasty in China, and the Gupta Empire in India, collectively around 500 CE.

Post-classical era is also called the Medieval period or the Middle Ages. It begins around 500 CE after the fall of major civilisations, covering the advent of Islam. The period ends around 1450–1500, with events like the rise of moveable-type printing in Europe, the voyages of Christopher Columbus, and the Ottoman Empire's conquest of Constantinople.

Archaeologically:

  1. Stone age
  2. Bronze Age
  3. Iron age

Historically:

  1. Prehistory (~2.5 MYA - ~3,600 BC)
  2. Ancient history (~3,600 BC - ~500 CE)
  3. Medieval history (~500 - ~1500)
  4. Modern history (~1500 - Present)

Geologic time scales edit

 
This clock representation shows some of the major units of geological time and definitive events of Earth history. The Hadean eon represents the time before fossil record of life on Earth; its upper boundary is now regarded as 4.0 Ga (billion years ago).[7] Other subdivisions reflect the evolution of life; the Archean and Proterozoic are both eons, the Palaeozoic, Mesozoic and Cenozoic are eras of the Phanerozoic eon. The two million year Quaternary period, the time of recognisable humans, is too small to be visible at this scale.

Modern Geologic time scale categories edit

  1. Superaeon or Supereon
  2. Aeon or Eon
  3. Era
  4. Period
  5. Epoch
  6. Age
  7. Chrone

Period was the only category used for time scales in early geology. Later era entered the terminology. Anything above the era was called simply time. Later, period was divided into epochs. Aeon was also included later in the terminology. Time became anything above an aeon, later being systematically renamed as a superaeon.

Aeon, era, period and epoch are the most commonly used categories in geological time scale. Epoch was further divided into ages. Some also divide ages into chrones, however this is not universally accepted.

The words age, era and times is always used in the spoken language vaguely to refer to any of the time scales above.

18th Century edit

The principles underlying geologic time scales were laid down by Nicholas Steno in the late 17th century. However it was only in the 18th century when the first serious attempts to formulate geological time scales were made. These attempts (championed by Abraham Werner, among others) first divided the rocks of the Earth's crust into three types as well as geological time scale into three periods:[8][9]

  1. Primary (oldest): Igneous and Metamorphic rocks; such as granite, rocks devoid of fossils and crystalline, forming the core of mountain ranges.
  2. Secondary: Shales, Limestones and Sandstones, containing fossils
  3. Tertiary (newest): Sedimentary rocks, containing fossils of still extant creatures and less consolidated, such as chalk.

Later a fourth category called the quaternary was added for the newest surface rocks, such as the surficial gravel. Each of these types of rocks, according to the prevalent theory of the age, had formed during a specific period in Earth history, thus corresponded to different "periods":[9]

  1. Primary Period: The oldest and longest period of earth history, from the formation of earth till the beginning of life. Corresponds to the Precambrian.
  2. Secondary Period: The evolution of life until the mammals. Corresponds to the totality of the Paleozoic and Mesozoic eras.
  3. Tertiary Period: Age of mammals. (First used by Charles Lyell as a systematic period name in 1833, however had been used by Giovanni Arduino and others in the 18th century as a simple division of rocks.)[9][10]
  4. Quaternary Period: Age of Humans.[11]

19th Century edit

The identification of strata by the fossils they contained, pioneered by William Smith, Georges Cuvier, Jean d'Omalius d'Halloy, and Alexandre Brogniart, in the early 19th century, enabled geologists to divide Earth history more precisely. It also enabled them to correlate strata across national (or even continental) boundaries. For example, if two strata (however distant in space or different in composition) contained the same fossils, chances were good that they had been laid down at the same time. Detailed studies between 1820 and 1850 of the strata and fossils of Europe produced the sequence of geological periods still used today. It also divided the secondary period, later started to be called an era, into 9 periods.

The process was dominated by British geologists, and the names of the periods reflect that dominance. However, some periods were defined by geologists from other countries as well.

Secondary Era:[10]

  1. Cambrian Period: The period was established by Adam Sedgwick in 1835, who named it after Cambria, the Latin name for Wales, where Britain's Cambrian rocks are best exposed. Recognised in the 1850s.
  2. Ordovician Period: The Ordovician, named after the Celtic tribe of Wales, the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in northern Wales into the Cambrian and Silurian periods, respectively.[12]
  3. Silurian Period: Named by Roderick Murchison in 1835, for a Celtic tribe of Wales, the Silures, inspired by Cambrian.
  4. Devonian Period: It is named after the English county of Devon, where rocks from this period were first studied, by William Lonsdale in 1837.[12] Devonian is often dubbed as the "Age of Fish".[11]
  5. Carboniferous Period: It's a Latin word meaning coal-bearing, coined as an adaptation of "the Coal Measures", the old British geologists' term for the same set of strata. It was coined by William Conybeare and William Phillips in 1822. Based on a study of the British rock succession, it was the first of the modern 'system' names to be employed and reflects the fact that many coal beds were formed globally during this time.
  6. Permian Period: The concept of the Permian was introduced in 1841 by the Scottish geologist Roderick Murchison, who named it after the ancient kingdom of Permia, which is today in Russia.
  7. Triassic Period: The "Triassic" was named in 1834 by a German geologist Friedrich Von Alberti from the three distinct layers (Latin trias meaning triad) —red beds, capped by chalk, followed by black shales— that are found throughout Germany and Northwest Europe, called the 'Trias'.
  8. Jurassic Period: Named by a French geologist Alexandre Brogniart in 1829 for the extensive marine limestone exposures of the Jura Mountains. Previously in 1799, von Humboldt had named its' formations as Jura Kalkstein as well.
  9. Cretaceous Period: From the term Terrain Cretace used in 1882 by Jean d'Omalius d'Halloy for chalk and greensand of northern France (Latin creta means 'chalk'). d'Omalius d'Halloy coined it as a separate period, using strata in the Paris basin and named for the extensive beds of chalk (calcium carbonate deposited by the shells of marine invertebrates).[13]
 
Example of proposed geological time scales from 1888.

In the second half of the 19th century, the British geologists were responsible for the grouping of periods into eras and the subdivision of the Tertiary and Quaternary periods into epochs. Very often the terms lower, middle and upper entered the vocabulary as adjectives for forming epochs. In 1841 John Phillips published the first global geological time scale based on the types of fossils found in each era. Phillips' scale helped standardise the use of terms like Palaeozoic ("old life") which he extended to cover a larger period than it had in previous usage, and Mesozoic ("middle life") which he invented.[14]

By the end of the century, the terminology and the classification was still changing. The term Precambrian was coined after the popularisation of the concept of Cambrian. Primary was substituted by this Precambrian Time. Now with some reclassification, our earth's history was divided into 5 lengths of time called eras. From oldest to the youngest these were:[8]

  1. Archaeozoic Era ("First life")
  2. Proterozoic Era ("Earlier life")
  3. Palaeozoic Era ("Old/Ancient life")
  4. Mesozoic Era ("Middle life")
  5. Cenozoic Era ("New life")
  • The first two, Archaeozoic and Proterozoic constituted the Precambrian Time or the previous Primary.
  • The next two, Palaeozoic and Mesozoic was what was previously known as the Secondary.
    • Palaeozoic took the first 6 periods of the Secondary, from Cambrian to Permian.
    • Mesozoic had the last 3 periods, Triassic, Jurassic and Cretaceous.
  • Tertiary and Quaternary combined to give the Cenozoic Era. Although the terms tertiary and quaternary stayed popularly in use until today.[8]

20th Century edit

The first geologic time scale that included absolute dates was published in 1913 by the British geologist Arthur Holmes. He greatly furthered the newly created discipline of geochronology and published the world renowned book The Age of the Earth.[11][15]

The shape that classification took place at the mid-20th century is as follows:

  • An aeon is the biggest time scale.
  • Aeons are divided into eras.
  • Eras are divided into periods.
  • And periods are divided into epochs.

Classification (1960)[16]

  1. Precambrian Aeon
    1. Archaeozoic Era
    2. Proterozoic Era
  2. Phanerozoic Aeon ("Visible life")
    1. Palaeozoic Era
      1. Cambrian Period (Lower, Middle and Upper Epochs)
      2. Ordovician Period
      3. Silurian Period
      4. Devonian Period (Lower, Middle and Upper Epochs)
      5. Carboniferous Period (Mississippian and Pennsylvanian Epochs)
      6. Permian Period (Lower, Middle and Upper Epochs)
    2. Mesozoic Era
      1. Triassic Period (Lower, Middle and Upper Epochs)
      2. Jurassic Period (Lower, Middle and Upper Epochs)
      3. Cretaceous Period (Lower, Middle and Upper Epochs)
    3. Cenozoic Era
      1. Palaeocene Period ("Old Recent")
      2. Eocene Period ("Dawn Recent")
      3. Oligocene Period ("Few Recent")
      4. Miocene Period ("Less Recent")
      5. Pliocene Period ("More Recent")
      6. Pleistocene Period ("Most Recent"): Equivalent to the then Quaternary Period. The other periods of the Cenozoic together makes the Tertiary period. Tertiary sometimes is used as a synonym of the Cenozoic Era, omitting entirely the Quaternary.

Until the end of the century, this classification more or less remained the same, although it kept on diversifying and systematising.[8]

21th Century edit

The ICS redefines the time scale terms by binding them to specific time intervals:

  • An aeon or eon is 500,000,000 years or more.
  • An era is several 100,000,000 years.
  • A period is less than an era and more than an epoch.
  • An epoch is several 10,000,000 years. (tens of millions)
  • An age is millions of years.
  • A chrone is smaller than an age, however it's not used by the ICS.
  • Archaeozoic has been renamed as Archaean.
  • Precambrian has been reclassified as and elevated to the level of superaeon. It's the only superaeon. Thus the Hadean, Archaean and Proterozoic eras have also been elevated to the level of aeons. Thus we have 4 aeons now, the first three consisting the Precambrian Superaeon:
  1. Hadean
  2. Archaean
  3. Proterozoic
  4. Phanerozoic
  • The Pleistocene (formerly Quaternary) Period of the Cenozoic Era is divided into Pleistocene and Holocene. Holocene covers the last 13,000 or 15,000 years of history. It literaly means "entirely recent" in Greek.[17]
  • The Cenozoic Era, readapts the usage of Tertiary and Quaternary Periods, turning the ...cene periods into epochs. The Tertiary however gets divided into two:
    • The Lower (or Early) Tertiary or Palaeogene ("Ancient-born")
    • The Upper (or Late) Tertiary or Neogene ("New-born")
  • The ICS recommends and uses Paleogene and Neogene.
  • The most recent classification is used below.[18]


Classical time scales from late 1990s Most recent ICS time scales
  1. Precambrian Aeon (4.5 BYA - 540 MYA)
    1. Hadean Era (4.5 BYA - 4 BYA)
    2. Archaeozoic Era (4 - 2.5 BYA)
    3. Proterozoic Era (2.5 - 0.54 BYA)
  2. Phanerozoic Aeon (540 MYA - today)
    1. Palaeozoic Era (540 - 250 MYA)
      1. Cambrian Period (540 - 485 MYA)
      2. Ordovician Period (485 - 443 MYA)
      3. Silurian Period (443 - 420 MYA)
      4. Devonian Period (420 - 360 MYA)
      5. Carboniferous Period (360 - 300 MYA)
      6. Permian Period (300 - 250 MYA)
    2. Mesozoic Era (250 - 66 MYA)
      1. Triassic Period (250 - 200 MYA)
      2. Jurassic Period (200 - 145 MYA)
      3. Cretaceous Period (145 - 66 MYA)
    3. Cenozoic Era (66 MYA - today)
      1. Palaeocene Period (66 - 56 MYA)
      2. Eocene Period (56 - 34 MYA)
      3. Oligocene Period (34 - 23 MYA)
      4. Miocene Period (23 - 5.3 MYA)
      5. Pliocene Period (5.3 - 2.6 MYA)
      6. Pleistocene Period (Quaternary) (2.6 MYA - today)
  1. Haden Aeon (4.5 BYA - 4 BYA)
  2. Archaean Aeon (4 - 2.5 BYA)
  3. Proterozoic Aeon (2.5 - 0.54 BYA) (these 3 under Precambrian Superaeon)
  4. Phanerozoic Aeon (540 MYA - today)
    1. Palaeozoic Era (540 - 250 MYA)
      1. Cambrian Period (540 - 485 MYA)
      2. Ordovician Period (485 - 443 MYA)
      3. Silurian Period (443 - 420 MYA)
      4. Devonian Period (420 - 360 MYA)
      5. Carboniferous Period (360 - 300 MYA)
      6. Permian Period (300 - 250 MYA)
    2. Mesozoic Era (250 - 66 MYA)
      1. Triassic Period (250 - 200 MYA)
      2. Jurassic Period (200 - 145 MYA)
      3. Cretaceous Period (145 - 66 MYA)
    3. Cenozoic Era (66 MYA - today)
      1. Palaeogene Period (early tertiary) (66 - 23 MYA)
        1. Palaeocene Epoch (66 - 56 MYA)
        2. Eocene Epoch (56 - 34 MYA)
        3. Oligocene Epoch (34 - 23 MYA)
      2. Neogene Period (late tertiary) (23 MYA - today)
        1. Miocene Epoch (23 - 5.3 MYA)
        2. Pliocene Epoch (5.3 - 2.6 MYA)
      3. Quaternary Period (2.6 MYA - today)
        1. Pleistocene Epoch (2.6 MYA - 15,000 YA)
        2. Holocene Epoch (15,000 YA - today)

Universe to Earth (14 - 4.54 BYA) edit

14    BYA      —     Formation of the universe[19][b]
13 .6    BYA      —     Formation of first stars
13 .2    BYA      —     Formation of first galaxies
10 .1    BYA      —     Commencement of the formation of Milky Way
8    BYA      —     Formation of the molecular cloud that will form the sun and the solar system[20][c]
4 .568    BYA      —     Sun and the solar system take shape.
4 .54    BYA      —     Formation of earth in its primordial form

Precambrian Superaeon edit

4.54 BYA till 541 MYA

Hadean Aeon (4.54 - 4 BYA) edit

4 .5    BYA      —     Formation of the moon from earth
4 .45    BYA      —     First rains and oceans
4 .4    BYA      —     First minerals

Archaean Aeon (4 - 2.5 BYA) edit

Proterozoic Aeon (2500 - 541 MYA) edit

Phanerozoic Aeon edit

541 MYA till Today

Palaeozoic Era (541 - 252 MYA) edit

Cambrian Period (541 - 485.4 MYA) edit

Ordovician Period (485.4 - 443.4 MYA) edit

Silurian Period (443.4 - 419.2 MYA) edit

Devonian Period (419.2 - 358.9 MYA) edit

Carboniferous Period (358.9 - 298.9 MYA) edit

Permian Period (298.9 - 252.2 MYA) edit

Mesozoic Era (252 - 66 MYA) edit

Triassic Period (252.2 - 201.3 MYA) edit

Jurassic Period (201.3 - 145 MYA) edit

Cretaceous Period (145 - 66 MYA) edit

Cenozoic Era (66 MYA - Today) edit

Palaeogene Period (66 - 23 MYA) edit

Palaeocene Epoch (66 - 56 MYA) edit
Eocene Epoch (56 - 34 MYA) edit
Oligocene Epoch (34 - 23 MYA) edit

Neogene Period (23 - 2.6 MYA) edit

Miocene Epoch (23 - 5.3 MYA) edit
Pliocene Epoch (5.3 - 2.6 MYA) edit

Quaternary Period (2.6 MYA - Today) edit

Pleistocene Epoch (2.6 MYA - 13,000 BC) edit
Holocene Epoch (13,000 BC - Today) edit

Stone-Bronze-Iron Periodisation edit

Stone Age edit

Bronze Age edit

Iron Age edit

Prehistory edit

Ancient History edit

Medieval History edit

Modern History edit

Abbreviations and symbols edit

The abbreviations and symbols included here are listed as follows:

  • app. -- approximately
  • BY -- Billion (109) Years
  • BYA -- Billion (109) Years Ago
  • MY -- Million (106) Years
  • MYA -- Million (106) Years Ago
  • + -- More than
  • ~ -- approximately

Citations edit

Notes edit

  1. ^ The terminology and the dates given in this page might not always comply with the most recent or major views in the academic chambers. However each major difference is indicated through citations. Some dates might be rounded when there's dispute about the exact date or a definitive proof of their date doesn't exist. This article might contain few original research ideas, again each time annotated through citations.
  2. ^ The exact age of the universe is unknown. The latest ΛCDM model gives the age of the universe as 13.799 BY ± 21 MY, the age that most scientist agrees upon. Some other methods (using Hubbert constant) however, gives the age at ~14.422 BY ± 164 MY. The visible universe is at least 13.2 BY old. The oldest star is at least 13.66 BY old. So, the universe is deducted to be older than that. According to some other formerly popular models and estimations, the universe has to be between 11 to 18 BY old. In the 1970s and 80s, the universe was thought to be 17.461 BY old. Today according to most of the scientists the universe is between 13 to 15 BY old. Moreover, some researchers in 2015 have created successful models that applies quantum correction terms to complement Einstein's theory of general relativity, demonstrating that the universe has no beginning in time and may have existed forever.
  3. ^ "...this planet earth was created after dissociation from the sun about 8,000 million years ago. At that time this earth was only a gaseous substance... Subsequently that gas cooled and gradually solidified to form the earth."

References edit

  1. ^ "History Definition". Retrieved 21 January 2014.
  2. ^ a b c d "Online Etymological Dictionary". Retrieved 11 November 2014.
  3. ^ Sarkar, Prabhat Ranjan (27 April 1980). "The Faculty of Knowledge – 1". The Faculty of Knowledge. Calcutta: A.N. Avadhúta. {{cite book}}: |access-date= requires |url= (help)
  4. ^ "ἱστορία". http://www.perseus.tufts.edu/hopper/. A Greek-English Lexicon. Retrieved 12 November 2014. {{cite web}}: External link in |website= (help)
  5. ^ Anandamurti, Shrii Shrii (11 December 1978). "The Four Vargas and Devotion". Ananda Vacanamrtam Part VI. Calcutta.{{cite book}}: CS1 maint: location missing publisher (link)
  6. ^ Prabhat Ranjan, Sarkar (28 February 1980). "What Should History Be Like?". A Few Problems Solved, Part 4.
  7. ^ International Commission on Stratigraphy 2008: stratigraphy.org, retrieved 9 March 2009.
  8. ^ a b c d Evans, Lawrence (1999). Nature's Holism. Lincoln, Nebraska: toExcel Press. pp. 47, 58–64. ISBN 1-58348-291-1. Retrieved 1 November 2014.
  9. ^ a b c "Tertiary Period". http://www.britannica.com/. Encyclopædia Britannica. Retrieved 1 November 2014. {{cite web}}: External link in |website= (help)
  10. ^ a b "Origin of Some of the Names on the Geologic Time Scale". http://comp.uark.edu/. Retrieved 1 November 2014. {{cite web}}: External link in |website= (help)
  11. ^ a b c "Geological Time Scale". http://www.enchantedlearning.com/. Retrieved 1 November 2014. {{cite web}}: External link in |website= (help)
  12. ^ a b John McPhee, Basin and Range, pp. 113–114.
  13. ^ Great Soviet Encyclopedia (in Russian) (3rd ed.). Moscow: Sovetskaya Enciklopediya. 1974. vol. 16, p. 50. {{cite encyclopedia}}: Unknown parameter |nopp= ignored (|no-pp= suggested) (help)
  14. ^ Rudwick, Martin Worlds Before Adam: The Reconstruction of Geohistory in the Age of Reform (2008) pp. 539–545
  15. ^ Holmes, Arthur (1913). The Age of the Earth. London & New York: Harper & Brothers. Retrieved 1 November 2014.
  16. ^ a b Roubault, M. "A Comparative Table of Recently Published Geological Time-Scales for the Phanerozoic Time - Explanatory Notice" (PDF). Norsk Geologisk Tidsskrift "Norwegian Journal of Geology" (47). International Union of Geological Sciences: 375–379. Retrieved 1 November 2014.
  17. ^ "The Geologic Time Scale". http://www.scienceviews.com/. Retrieved 2 November 2014. {{cite web}}: External link in |website= (help)
  18. ^ "Stratigraphic Chart - GTS2012". https://engineering.purdue.edu/. Geologic TimeScale Foundation. Retrieved 1 November 2014. {{cite web}}: External link in |website= (help)
  19. ^ Bennett, C.L. (20 September 2013). "NINE-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE (WMAP) OBSERVATIONS: FINAL MAPS AND RESULTS". The Astrophysical Journal Supplement Series. 208 (2). doi:10.1088/0067-0049/208/2/20. Retrieved 1 November 2014.
  20. ^ Sarkar, Prabhat Ranjan (July 1967). "Sambhúti and Mahásambhúti". Subháśita Saḿgraha Part 9 (Electonic Edition 7.5 ed.). New Delhi. {{cite book}}: |access-date= requires |url= (help)CS1 maint: location missing publisher (link)