Deep time

Deep time is the concept of geologic time. The modern philosophical concept was developed in the 18th century by Scottish geologist James Hutton (1726–1797).[1][2] The age of the Earth has been determined to be, after a long and complex history of developments, around 4.55 billion years.[3]

Scientific concept

Hutton based his view of deep time on a form of geochemistry that had developed in Scotland and Scandinavia from the 1750s onward.[4] As mathematician John Playfair, one of Hutton's friends and colleagues in the Scottish Enlightenment, remarked upon seeing the strata of the angular unconformity at Siccar Point with Hutton and James Hall in June 1788, "the mind seemed to grow giddy by looking so far into the abyss of time".[5][6]

Early geologists such as Nicolas Steno (1638-1686) and Horace-Bénédict de Saussure (1740-1799) had developed ideas of geological strata forming from water through chemical processes, which Abraham Gottlob Werner (1749–1817) developed into a theory known as Neptunism, envisaging the slow crystallisation of minerals in the ancient oceans of the Earth to form rock. Hutton's innovative 1785 theory, based on Plutonism, visualised an endless cyclical process of rocks forming under the sea, being uplifted and tilted, then eroded to form new strata under the sea. In 1788 the sight of Hutton's Unconformity at Siccar Point convinced Playfair and Hall of this extremely slow cycle, and in that same year Hutton memorably wrote "we find no vestige of a beginning, no prospect of an end".[7][8]

Other scientists such as Georges Cuvier (1769-1832) put forward ideas of past ages, and geologists such as Adam Sedgwick (1785-1873) incorporated Werner's ideas into concepts of catastrophism; Sedgwick inspired his university student Charles Darwin to exclaim "What a capital hand is Sedgewick [sic] for drawing large cheques upon the Bank of Time!".[9] In a competing theory, Charles Lyell in his Principles of Geology (1830–1833) developed Hutton's comprehension of endless deep time as a crucial scientific concept into uniformitarianism. As a young naturalist and geological theorist, Darwin studied the successive volumes of Lyell's book exhaustively during the Beagle survey voyage in the 1830s, before beginning to theorise about evolution.

Physicist Gregory Benford addresses the concept in Deep Time: How Humanity Communicates Across Millennia (1999), as does paleontologist and Nature editor Henry Gee in In Search of Deep Time: Beyond the Fossil Record to a New History of Life (2001)[10][11] Stephen Jay Gould's Time's Arrow, Time's Cycle (1987) also deals in large part with the evolution of the concept.

John McPhee discussed "deep time" at length with the layperson in mind in Basin and Range (1981), parts of which originally appeared in the New Yorker magazine.[12] In Time's Arrow, Time's Cycle, Gould cited one of the metaphors McPhee used in explaining the concept of deep time:

Consider the Earth's history as the old measure of the English yard, the distance from the King's nose to the tip of his outstretched hand. One stroke of a nail file on his middle finger erases human history.[12]

Concepts similar to geologic time were recognized in the 11th century by the Persian geologist and polymath Avicenna (Ibn Sina, 973–1037),[13] and by the Chinese naturalist and polymath Shen Kuo (1031–1095).[14]

The Roman Catholic theologian Thomas Berry (1914–2009) explored spiritual implications of the concept of deep time. Berry proposes that a deep understanding of the history and functioning of the evolving universe is a necessary inspiration and guide for our own effective functioning as individuals and as a species. This view has greatly influenced the development of deep ecology and ecophilosophy. The experiential nature of the experience of deep time has also greatly influenced the work of Joanna Macy and John Seed.

H.G. Wells and Julian Huxley regarded the difficulties of coping with the concept of deep time as exaggerated:

"The use of different scales is simply a matter of practice", they said in The Science of Life (1929). "We very soon get used to maps, though they are constructed on scales down to a hundred-millionth of natural size. . .  to grasp geological time all that is needed is to stick tight to some magnitude which shall be the unit on the new and magnified scale—a million years is probably the most convenient—to grasp its meaning once and for all by an effort of imagination, and then to think of all passage of geological time in terms of this unit."[15]

See also


  1. ^ Palmer & Zen.
  2. ^ Kubicek 2008.
  3. ^ Braterman, Paul S. "How Science Figured Out the Age of Earth". Scientific American. Retrieved 2016-04-17.
  4. ^ Eddy, Matthew Daniel (2008). The Language of Mineralogy: John Walker, Chemistry and the Edinburgh Medical School 1750-1800. London: Ashgate. p. Ch. 5.
  5. ^ Playfair 1805.
  6. ^ McPhee, John (1981). Book 1: Basin and Range, in Annals of the Former World. New York: Farrar, Straus and Giroux. p. 79. ISBN 0-374-10520-0.
  7. ^ Montgomery 2003.
  8. ^ Rance 1999.
  9. ^ Darwin 1831.
  10. ^ Korthof 2000.
  11. ^ Campbell 2001.
  12. ^ a b McPhee 1998, p. 77.
  13. ^ Toulmin & Goodfield 1965, p. 64.
  14. ^ Sivin 1995, pp. iii,23-24.
  15. ^ H.G. Wells, Julian S. Huxley, and G.P. Wells, The Science of Life (New York: The Literary Guild, 1934; orig. publ. 1929), p. 326.



External links

Big Bang Generation

Big Bang Generation is a BBC Books original novel written by Gary Russell and based on the long-running British science fiction television series Doctor Who. It features the Twelfth Doctor and Bernice Summerfield, making her first appearance in the New Series Adventures along with the Doctor from the revived series. The book was released on 10 September 2015 as a part of The Glamour Chronicles, alongside Royal Blood and Deep Time.

Carpe diem

Carpe diem is a Latin aphorism, usually translated "seize the day", taken from book 1 of the Roman poet Horace's work Odes (23 BC).


A chronicle (Latin: chronica, from Greek χρονικά chroniká, from χρόνος, chrónos – "time") is a historical account of facts and events arranged in chronological order, as in a time line. Typically, equal weight is given for historically important events and local events, the purpose being the recording of events that occurred, seen from the perspective of the chronicler. This is in contrast to a narrative or history, which sets selected events in a meaningful interpretive context and excludes those the author does not see as important.

Chronicler information sources vary; some chronicles are written from first-hand knowledge, some are from witnesses or participants in events, still others are accounts passed mouth to mouth prior to being written down. Some used written material: Charters, letters, or the works of earlier chroniclers. Still others are tales of such unknown origins so as to hold mythical status. Copyists also affected chronicles in creative copying, making corrections or in updating or continuing a chronicle with information not available to the original author(s). The reliability of a particular chronicle is an important determination for modern historians.In modern times various contemporary newspapers or other periodicals have adopted "chronicle" as part of their name. Various fictional stories have also adopted "chronicle" as part of their title, to give an impression of epic proportion to their stories. A chronicle which traces world history is called a universal chronicle.


Chronology (from Latin chronologia, from Ancient Greek χρόνος, chrónos, "time"; and -λογία, -logia) is the science of arranging events in their order of occurrence in time. Consider, for example, the use of a timeline or sequence of events. It is also "the determination of the actual temporal sequence of past events".Chronology is a part of periodization. It is also a part of the discipline of history including earth history, the earth sciences, and study of the geologic time scale.


Chronometry (from Greek χρόνος chronos, "time" and μέτρον metron, "measure") is the science of the measurement of time, or timekeeping. Chronometry applies to electronic devices, while horology refers to mechanical devices.

It should not to be confused with chronology, the science of locating events in time, which often relies upon it.


Circa (from Latin, meaning 'around, about, roughly, approximately') – frequently abbreviated c., ca., or ca and less frequently circ. or cca. – signifies "approximately" in several European languages and as a loanword in English, usually in reference to a date. Circa is widely used in historical writing when the dates of events are not accurately known.

When used in date ranges, circa is applied before each approximate date, while dates without circa immediately preceding them are generally assumed to be known with certainty.


1732–1799: Both years are known precisely.

c. 1732 – 1799: The beginning year is approximate; the end year is known precisely.

1732 – c. 1799: The beginning year is known precisely ; the end year is approximate.

c. 1732 – c. 1799: Both years are approximate.

Common year

A common year is a calendar year with 365 days, as distinguished from a leap year, which has 366. More generally, a common year is one without intercalation. The Gregorian calendar, (like the earlier Julian calendar), employs both common years and leap years to keep the calendar aligned with the tropical year, which does not contain an exact number of days.

The common year of 365 days has 52 weeks and one day, hence a common year always begins and ends on the same day of the week (for example, January 1 and December 31 fell on a Sunday in 2017) and the year following a common year will start on the subsequent day of the week. In common years, February has four weeks, so March will begin on the same day of the week. November will also begin on this day.

In the Gregorian calendar, 303 of every 400 years are common years. By comparison, in the Julian calendar, 300 out of every 400 years are common years, and in the Revised Julian calendar (used by Greece) 682 out of every 900 years are common years.

Deep Time (novel)

Deep Time is a BBC Books original novel written by Trevor Baxendale and based on the long-running British science fiction television series Doctor Who. It features the Twelfth Doctor and Clara Oswald. The book was released on 10 September 2015 as a part of The Glamour Chronicles, alongside Royal Blood and Big Bang Generation.


Floruit (UK: , US: ), abbreviated fl. (or occasionally flor.), Latin for "he/she flourished", denotes a date or period during which a person was known to have been alive or active. In English, the word may also be used as a noun indicating the time when someone flourished.


Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, whereas relative geochronology is provided by tools such as palaeomagnetism and stable isotope ratios. By combining multiple geochronological (and biostratigraphic) indicators the precision of the recovered age can be improved.

Geochronology is different in application from biostratigraphy, which is the science of assigning sedimentary rocks to a known geological period via describing, cataloging and comparing fossil floral and faunal assemblages. Biostratigraphy does not directly provide an absolute age determination of a rock, but merely places it within an interval of time at which that fossil assemblage is known to have coexisted. Both disciplines work together hand in hand, however, to the point where they share the same system of naming rock layers and the time spans utilized to classify layers within a stratum.

The science of geochronology is the prime tool used in the discipline of chronostratigraphy, which attempts to derive absolute age dates for all fossil assemblages and determine the geologic history of the Earth and extraterrestrial bodies.

Geologic time scale

The geologic time scale (GTS) is a system of chronological dating that relates geological strata (stratigraphy) to time. It is used by geologists, paleontologists, and other Earth scientists to describe the timing and relationships of events that have occurred during Earth's history. The table of geologic time spans, presented here, agree with the nomenclature, dates and standard color codes set forth by the International Commission on Stratigraphy (ICS).


HD2IOA is the callsign of a time signal radio station operated by the Navy of Ecuador. The station is located at Guayaquil, Ecuador and transmits in the HF band on 3.81 and 7.6 MHz.The transmission is in AM mode with only the lower sideband (part of the time H3E and the rest H2B/H2D) and consists of 780 Hz tone pulses repeated every ten seconds and voice announcements in Spanish.

While sometimes this station is described as defunct, reception reports of this station on 3.81 MHz appear regularly at the Utility DX Forum.

Intercalation (timekeeping)

Intercalation or embolism in timekeeping is the insertion of a leap day, week, or month into some calendar years to make the calendar follow the seasons or moon phases. Lunisolar calendars may require intercalations of both days and months.


The minute is a unit of time or angle. As a unit of time, the minute is most of times equal to ​1⁄60 (the first sexagesimal fraction) of an hour, or 60 seconds. In the UTC time standard, a minute on rare occasions has 61 seconds, a consequence of leap seconds (there is a provision to insert a negative leap second, which would result in a 59-second minute, but this has never happened in more than 40 years under this system). As a unit of angle, the minute of arc is equal to ​1⁄60 of a degree, or 60 seconds (of arc). Although not an SI unit for either time or angle, the minute is accepted for use with SI units for both. The SI symbols for minute or minutes are min for time measurement, and the prime symbol after a number, e.g. 5′, for angle measurement. The prime is also sometimes used informally to denote minutes of time.

New Earth Time

New Earth Time (or NET) is an alternative naming system for measuring the time of day. In NET the day is split into 360 NET degrees, each NET degree is split into 60 NET minutes and each NET minute is split into 60 NET seconds. One NET degree is therefore equivalent to four standard minutes, and one standard hour is equivalent to 15 NET degrees.

NET is equivalent to the UTC read from a 24-hour analog clock as the clockwise angle past midnight of the hour hand. For example, noon is 180°0'0" NET and at that time the hour hand is pointing straight down forming a 180° angle when measured from the top, at midnight. A full circle is 360 degrees and one NET day.

Royal Blood (novel)

Royal Blood is a BBC Books original novel written by Una McCormack and based on the long-running British science fiction television series Doctor Who. It features the Twelfth Doctor and Clara Oswald. The book was released on 10 September 2015 as a part of The Glamour Chronicles, alongside Big Bang Generation and Deep Time.

Tempus fugit

Tempus fugit is a Latin phrase, usually translated into English as "time flies". The expression comes from line 284 of book 3 of Virgil's Georgics, where it appears as fugit inreparabile tempus: "it escapes, irretrievable time". The phrase is used in both its Latin and English forms as a proverb that "time's a-wasting". Tempus fugit, however, is typically employed as an admonition against sloth and procrastination (cf. carpe diem) rather than a motto in favor of licentiousness (cf. "gather ye rosebuds while ye may"); the English form is often merely descriptive: "time flies like the wind", "time flies when you're having fun".

The phrase's full appearance in the Georgics is:

The phrase is a common motto, particularly on sundials and clocks.


A timeline is a display of a list of events in chronological order. It is typically a graphic design showing a long bar labelled with dates paralleling it, and usually contemporaneous events; a Gantt chart is a form of timeline used in project management.

Timelines can use any suitable scale representing time, suiting the subject and data; many use a linear scale, in which a unit of distance is equal to a set amount of time. This timescale is dependent on the events in the timeline. A timeline of evolution can be over millions of years, whereas a timeline for the day of the September 11 attacks can take place over minutes, and that of an explosion over milliseconds. While many timelines use a linear timescale -- especially where very large or small timespans are relevant -- logarithmic timelines entail a logarithmic scale of time; some "hurry up and wait" chronologies are depicted with zoom lens metaphors.

Yesterday (time)

Yesterday is a temporal construct of the relative past; literally of the day before the current day (today), or figuratively of earlier periods or times, often but not always within living memory.

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