time

• n

• 時間, 時, 時期, 期間, ～倍の

most of the time 大抵の場合は

• in time

関

duration、fold、hour、hr、long-term effect、moment、period、phase、stage、term

　 　 　 　 　 　 　 　 　 　 　

WordNet

1. set the speed, duration, or execution of; "we time the process to manufacture our cars very precisely"
2. a period of time considered as a resource under your control and sufficient to accomplish something; "take time to smell the roses"; "I didnt have time to finish"; "it took more than half my time"
3. a suitable moment; "it is time to go"
4. adjust so that a force is applied and an action occurs at the desired time; "The good player times his swing so as to hit the ball squarely"
5. an indefinite period (usually marked by specific attributes or activities); "he waited a long time"; "the time of year for planting"; "he was a great actor in his time"
6. regulate or set the time of; "time the clock"
7. the continuum of experience in which events pass from the future through the present to the past
8. an instance or single occasion for some event; "this time he succeeded"; "he called four times"; "he could do ten at a clip" (同)clip
9. a persons experience on a particular occasion; "he had a time holding back the tears"; "they had a good time together"
10. assign a time for an activity or event; "The candidate carefully timed his appearance at the disaster scene"
11. bend or lay so that one part covers the other; "fold up the newspaper"; "turn up your collar" (同)fold up, turn up
12. an angular or rounded shape made by folding; "a fold in the napkin"; "a crease in his trousers"; "a plication on her blouse"; "a flexure of the colon"; "a bend of his elbow" (同)crease, plication, flexure, crimp, bend
13. a geological process that causes a bend in a stratum of rock (同)folding
14. incorporate a food ingredient into a mixture by repeatedly turning it over without stirring or beating; "Fold the egg whites into the batter"
15. the act of folding; "he gave the napkins a double fold" (同)folding
16. a pen for sheep (同)sheepfold, sheep pen, sheepcote
17. a folded part (as in skin or muscle) (同)plica
18. become folded or folded up; "The bed folds in a jiffy" (同)fold up
19. perform (a play), especially on a stage; "we are going to stage `Othello" (同)present, represent
20. a section or portion of a journey or course; "then we embarked on the second stage of our Caribbean cruise" (同)leg
21. a small platform on a microscope where the specimen is mounted for examination (同)microscope stage
22. a large platform on which people can stand and can be seen by an audience; "he clambered up onto the stage and got the actors to help him into the box"
23. any scene regarded as a setting for exhibiting or doing something; "All the worlds a stage"--Shakespeare; "it set the stage for peaceful negotiations"
24. the theater as a profession (usually `the stage'
25. plan, organize, and carry out (an event); "the neighboring tribe staged an invasion" (同)arrange
26. a unit of geological time during which a system of rocks formed; "ganoid fishes swarmed during the earlier geological periods" (同)geological period
27. (ice hockey) one of three divisions into which play is divided in hockey games
28. the end or completion of something; "death put a period to his endeavors"; "a change soon put a period to my tranquility"
29. the interval taken to complete one cycle of a regularly repeating phenomenon
30. a punctuation mark (.) placed at the end of a declarative sentence to indicate a full stop or after abbreviations; "in England they call a period a stop" (同)point, full_stop, stop, full point
31. arrange in phases or stages; "phase a withdrawal"
32. (physical chemistry) a distinct state of matter in a system; matter that is identical in chemical composition and physical state and separated from other material by the phase boundary; "the reaction occurs in the liquid phase of the system" (同)form
33. a particular point in the time of a cycle; measured from some arbitrary zero and expressed as an angle (同)phase_angle
34. any distinct time period in a sequence of events; "we are in a transitional stage in which many former ideas must be revised or rejected" (同)stage
35. adjust so as to be in a synchronized condition; "he phased the intake with the output of the machine"
36. (astronomy) the particular appearance of a bodys state of illumination (especially one of the recurring shapes of the part of Earths moon that is illuminated by the sun); "the full phase of the moon"
37. name formally or designate with a term
38. the end of gestation or point at which birth is imminent; "a healthy baby born at full term" (同)full term
39. a limited period of time; "a prison term"; "he left school before the end of term"
40. a word or expression used for some particular thing; "he learned many medical terms"
41. any distinct quantity contained in a polynomial; "the general term of an algebraic equation of the n-th degree"
42. one of the substantive phrases in a logical proposition; "the major term of a syllogism must occur twice"
43. an elderly man (同)oldtimer, gaffer, old geezer, antique
44. shrub with terminal tufts of elongated leaves used locally for thatching and clothing; thick sweet roots are used as food; tropical southeastern Asia, Australia and Hawaii (同)Cordyline terminalis
45. the syllable naming the seventh (subtonic) note of any musical scale in solmization (同)te, si
46. the regulation of occurrence, pace, or coordination to achieve a desired effect (as in music, theater, athletics, mechanics)
47. the time when something happens
48. a more or less definite period of time now or previously present; "it was a sign of the times"
49. regularly spaced in time; "closely timed intervals"

PrepTutorEJDIC

1. 〈U〉《冠詞をつけずに》(空間に対しての)『時間』,時 / 〈U〉(時計で示される)『時刻』 / 〈U〉(ある方式で決められる)『時間』,標準時 / 〈C〉〈U〉(特定の)『時』,おり,ころ / 〈U〉《しばしば A ~》(ある長さの)『時間』,期間 / 〈U〉(要する)『時間』;暇 / 《しばしば複数形で》(歴史上の)『時代』 / 《複数形で》時勢,景気 / 《one's ~》(個人の)一生;若いころ;生涯の特定の時期 / 〈U〉《しばしば A ~》(ある経験をした)『時間』 / 〈C〉『…回』,度 / 〈C〉『…倍』 / …の時間を定める / (…に)…の調子を合わせる《+名+to+名》 / …の時間を計る
2. 《副語[句]を伴って》〈紙など〉‘を'『折る』,折り重ねる / 〈両手など〉‘を'『組む』;〈鳥が〉〈翼〉‘を'畳む / (…に)…‘を'巻き付ける《+『around(about)』+『名』》 / …‘を'抱き締める(embrace) / 《副語[句]を伴って》〈扇などが〉折リ畳める / 《話》〈事業などが〉つぶれる,閉じる《+『up』》 / ひだ / 折り目,畳み目 / (土地の)くぼみ / 起伏
3. (家畜,特に羊を入れておく)囲い,おり / 《比喩(ひゆ)的に》キリスト教会
4. (劇場・ホールなどの)『舞台』・on stage 舞台上で・《無冠詞》・off stage 舞台の陰で 《無冠詞》：ステージ;演壇;《the~》演劇;俳優業,演劇(舞台)の仕事 / (事件・活動などの)『舞台』,場所 / (発達などの)『段階』,時期 / (駅馬車などの止まる)駅,宿場;休憩地;(旅行における休憩地間の)旅程,行程 / =stagecoach / (多段ロケットの)段 / 〈劇〉‘を'『上演する』,〈試合など〉‘を'公開する / (特に劇的に)…‘を'実行する,やってのける
5. (あることが続く)『期間』 / (歴史的な)『時代』 / (試合の)『一区切り』,ピリオド / 授業時間,時限: / (循環して起こる現象などの)周期 / (回転運動などの)周期 / 紀(地質時代の区分の一つ;era(代)の下,epoch(世)の上) / 《おもに米》『ピリオド』,終止符(《英》full stop;Mr.,U.S.など略語の符号(.)も含む) / 《複数形で》《文》掉尾(とうび)文(多くの節から成り,論理的に緊密な構成をもっている文) / 《名詞の前にのみ用いて》ある時代[特有]の,時代物の / (文の終わりに感嘆詞的に)以上,終わり・月経（期間）
6. (変化・発達の)『段階』,『局面』 / (物事の)『面』,様相《+『of』+『名』》 / (月・惑星などの)相 / …‘を'段階的に調整(整理)する
7. 〈C〉『専門用語』,術語 / 〈C〉(一般に)語[句],言葉 / 《複数形で》言い道,言飯遣い / 〈C〉『期間』 / 〈C〉〈U〉『学期』 / 《複数形で》(人との)間柄,仲《+with+名》 / 《複数形で》(協定などの)『条件』;要求額,値段 / 〈C〉(数式で)項 / 《term+名〈目〉+名(形)〈補〉》(…と)…‘を'名づける,呼ぶ
8. 古参者,古顔 / 《米》老人,年配者
9. (…の)(悪い)予感,胸騷ぎ《+『that節』》
10. シ(全音階の第7音)
11. 時間の調節;時間を測定[記録]すること
12. …掛ける

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/01/01 22:07:42」(JST)

wiki ja

[Wiki ja表示]

タイム

time

• 時間
• 時刻
• 球技などで、競技者が一時休止を申し出ること。タイムアウトの略。
  • 野球におけるタイムはボールデッドを参照
• タイム (雑誌) - アメリカ合衆国のニュース週刊誌
• タイム (エレクトリック・ライト・オーケストラのアルバム) - エレクトリック・ライト・オーケストラのアルバム
• タイム (フリートウッド・マックのアルバム) - フリートウッド・マックのアルバム
• タイム (マーシフル・フェイトのアルバム) - マーシフル・フェイトのアルバム
• タイム (自転車) - フランスの自転車部品製造会社。en:Time (bicycles)
• ホームセンタータイム - 中国地方や四国地方に14店舗を展開するホームセンター。
• タイムクライシスシリーズの略称 - ナムコのガンシューティングゲーム
• タイム (タバコ) - タバコの銘柄の1つ
• TIME - B'zの楽曲 シングル『BLOWIN'』の2nd beat（カップリング曲）
• Time - EXILEの楽曲 シングル『Breezin' 〜Together〜』のカップリング
• Time (嵐のアルバム) - 嵐のアルバム
• time (UNIX) - プログラム実行に要する時間や経過時間を計測するコマンド。
• TIME/タイム - 2011年のアメリカ映画。
• 『絶対の愛』の英題 - 韓国映画。
• TIME (レベッカのアルバム) - レベッカのアルバム。
• Time - KinKi Kidsの楽曲。31stのシングル。

thyme

• タイム (植物) - シソ科のハーブ
• タイム (カレーショップ) - ジェイアール東日本フードビジネス（ジェフビー）が関東の駅ナカに展開するチェーン店
• THYME - 日本のバンド

関連項目

• タイムズ (曖昧さ回避)
• タイミング
• タイマー

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wiki en

[Wiki en表示]

For other uses of "Time", see Time (disambiguation).

The flow of sand in an hourglass can be used to keep track of elapsed time. It also concretely represents the present as being between the past and the future.

Time
Major Concepts
Past ♦ Present ♦ Future Eternity Arguments for eternity
Broad Studies
Chronology History (Paleontology) Futurology
Philosophy
Presentism ♦ Eternalism, Fatalism Philosophy of Space and Time
Religion
Creation End Times Day of Judgement Immortality Afterlife ♦ Reincarnation Kalachakra
Time measurement and Standards
Metric Time ♦ Hexadecimal time
Related
Spacetime, Motion ♦ Space Event ♦ Continuum Time Travel ♦ (Grandfather Paradox)

Time is a dimension in which events can be ordered from the past through the present into the future, and also the measure of durations of events and the intervals between them. Time has long been a major subject of study in religion, philosophy, and science, but defining it in a manner applicable to all fields without circularity has consistently eluded scholars. Nevertheless, diverse fields such as business, industry, sports, the sciences, music, dance, and the live theater all incorporate some notion of time into their respective measuring systems. Some simple, relatively uncontroversial definitions of time include "time is what clocks measure" and "time is what keeps everything from happening at once".

Two contrasting viewpoints on time divide many prominent philosophers. One view is that time is part of the fundamental structure of the universe—a dimension independent of events, in which events occur in sequence. Sir Isaac Newton subscribed to this realist view, and hence it is sometimes referred to as Newtonian time. The opposing view is that time does not refer to any kind of "container" that events and objects "move through", nor to any entity that "flows", but that it is instead part of a fundamental intellectual structure (together with space and number) within which humans sequence and compare events. This second view, in the tradition of Gottfried Leibniz and Immanuel Kant, holds that time is neither an event nor a thing, and thus is not itself measurable nor can it be travelled.

Time is one of the seven fundamental physical quantities in the International System of Units. Time is used to define other quantities – such as velocity — so defining time in terms of such quantities would result in circularity of definition. An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. The operational definition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be measured. Investigations of a single continuum called spacetime bring questions about space into questions about time, questions that have their roots in the works of early students of natural philosophy.

Furthermore, it may be that there is a subjective component to time, but whether or not time itself is "felt", as a sensation or an experience, has never been settled.

Temporal measurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. Periodic events and periodic motion have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. Currently, the international unit of time, the second, is defined in terms of radiation emitted by caesium atoms (see below). Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human life spans.

Temporal measurement

Temporal measurement, or chronometry, takes two distinct period forms: the calendar, a mathematical abstraction for calculating extensive periods of time, and the clock, a physical mechanism that counts the ongoing passage of time. In day-to-day life, the clock is consulted for periods less than a day, the calendar, for periods longer than a day. Increasingly, personal electronic devices display both calendars and clocks simultaneously. The number (as on a clock dial or calendar) that marks the occurrence of a specified event as to hour or date is obtained by counting from a fiducial epoch – a central reference point.

History of the calendar

Main article: Calendar

Artifacts from the Palaeolithic suggest that the moon was used to reckon time as early as 6,000 years ago. Lunar calendars were among the first to appear, either 12 or 13 lunar months (either 354 or 384 days). Without intercalation to add days or months to some years, seasons quickly drift in a calendar based solely on twelve lunar months. Lunisolar calendars have a thirteenth month added to some years to make up for the difference between a full year (now known to be about 365.24 days) and a year of just twelve lunar months. The numbers twelve and thirteen came to feature prominently in many cultures, at least partly due to this relationship of months to years.

The reforms of Julius Caesar in 45 BC put the Roman world on a solar calendar. This Julian calendar was faulty in that its intercalation still allowed the astronomical solstices and equinoxes to advance against it by about 11 minutes per year. Pope Gregory XIII introduced a correction in 1582; the Gregorian calendar was only slowly adopted by different nations over a period of centuries, but is today by far the one in most common use around the world.

History of time measurement devices

Horizontal sundial in Taganrog.

Main article: History of timekeeping devices

See also: Clock

A large variety of devices have been invented to measure time. The study of these devices is called horology.

An Egyptian device that dates to c.1500 BC, similar in shape to a bent T-square, measured the passage of time from the shadow cast by its crossbar on a nonlinear rule. The T was orientated eastward in the mornings. At noon, the device was turned around so that it could cast its shadow in the evening direction.

A sundial uses a gnomon to cast a shadow on a set of markings calibrated to the hour. The position of the shadow marks the hour in local time.

The most precise timekeeping device of the ancient world was the water clock, or clepsydra, one of which was found in the tomb of Egyptian pharaoh Amenhotep I (1525–1504 BC). They could be used to measure the hours even at night, but required manual upkeep to replenish the flow of water. The Greeks and the people from Chaldea (southern Iraq) regularly maintained timekeeping records as an essential part of their astronomical observations. Arab inventors and engineers in particular made improvements on the use of water clocks up to the Middle Ages. In the 11th century, Chinese inventors and engineers invented the first mechanical clocks driven by an escapement mechanism.

A contemporary quartz watch

The hourglass uses the flow of sand to measure the flow of time. They were used in navigation. Ferdinand Magellan used 18 glasses on each ship for his circumnavigation of the globe (1522). Incense sticks and candles were, and are, commonly used to measure time in temples and churches across the globe. Waterclocks, and later, mechanical clocks, were used to mark the events of the abbeys and monasteries of the Middle Ages. Richard of Wallingford (1292–1336), abbot of St. Alban's abbey, famously built a mechanical clock as an astronomical orrery about 1330. Great advances in accurate time-keeping were made by Galileo Galilei and especially Christiaan Huygens with the invention of pendulum driven clocks.

The English word clock probably comes from the Middle Dutch word klocke—which, in turn, derives from the mediaeval Latin word clocca, which ultimately derives from Celtic and is cognate with French, Latin, and German words that mean bell. The passage of the hours at sea were marked by bells, and denoted the time (see ship's bells). The hours were marked by bells in abbeys as well as at sea.

Chip-scale atomic clocks, such as this one unveiled in 2004, are expected to greatly improve GPS location.

Clocks can range from watches, to more exotic varieties such as the Clock of the Long Now. They can be driven by a variety of means, including gravity, springs, and various forms of electrical power, and regulated by a variety of means such as a pendulum.

A chronometer is a portable timekeeper that meets certain precision standards. Initially, the term was used to refer to the marine chronometer, a timepiece used to determine longitude by means of celestial navigation, a precision firstly achieved by John Harrison. More recently, the term has also been applied to the chronometer watch, a wristwatch that meets precision standards set by the Swiss agency COSC.

The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generator and oscillator applications.

The most accurate timekeeping devices are atomic clocks, which are accurate to seconds in many millions of years, and are used to calibrate other clocks and timekeeping instruments. Atomic clocks use the spin property of atoms as their basis, and since 1967, the International System of Measurements bases its unit of time, the second, on the properties of caesium atoms. SI defines the second as 9,192,631,770 cycles of the radiation that corresponds to the transition between two electron spin energy levels of the ground state of the ¹³³Cs atom.

Today, the Global Positioning System in coordination with the Network Time Protocol can be used to synchronize timekeeping systems across the globe.

In medieval philosophical writings, the atom was a unit of time referred to as the smallest possible division of time. The earliest known occurrence in English is in Byrhtferth's Enchiridion (a science text) of 1010–1012, where it was defined as 1/564 of a momentum (1½ minutes), and thus equal to 15/94 of a second. It was used in the computus, the process of calculating the date of Easter.

As of May 2010, the smallest time interval uncertainty in direct measurements is on the order of 12 attoseconds (1.2 × 10⁻¹⁷ seconds), about 3.7 × 10²⁶ Planck times.

Definitions and standards

Units of time

Unit	Size	Notes
yoctosecond	10−24 s
zeptosecond	10−21 s
attosecond	10−18 s	shortest time uncertainty in present measurements
femtosecond	10−15 s	pulse time of ultrafast lasers (100 as = 0.1 fs)
picosecond	10−12 s
nanosecond	10−9 s	time for molecules to fluoresce
microsecond	10−6 s
millisecond	0.001 s
second	1 s	SI base unit
minute	60 seconds
hour	60 minutes
day	24 hours
week	7 days	Also called sennight
fortnight	14 days	2 weeks
lunar month	27.2–29.5 days	Various definitions exist.
lunation	29.53 days	One lunar phase cycle.
month	28–31 days
quarter	3 months
year	12 months
common year	365 days	52 weeks + 1-day
leap year	366 days	52 weeks + 2 days
tropical year	365.24219 days	average
Gregorian year	365.2425 days	average
Julian year	365.25 days
Olympiad	4-year cycle
lustrum	5 years	Also called pentad
decade	10 years
Indiction	15-year cycle
generation	17–35 years	approximate
jubilee	50 years
century	100 years
millennium	1,000 years
exasecond	1018 s	roughly 32 billion years, more than twice the age of the universe on current estimates
cosmological decade	varies	10 times the length of the previous cosmological decade, with CÐ 1 beginning either 10 seconds or 10 years after the Big Bang, depending on the definition.

See also: Time standard and Orders of magnitude (time)

The SI base unit for time is the SI second. From the second, larger units such as the minute, hour and day are defined, though they are "non-SI" units because they do not use the decimal system, and also because of the occasional need for a leap second. They are, however, officially accepted for use with the International System. There are no fixed ratios between seconds and months or years as months and years have significant variations in length.

The official SI definition of the second is as follows:

The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.

At its 1997 meeting, the CIPM affirmed that this definition refers to a caesium atom in its ground state at a temperature of 0 K. Previous to 1967, the second was defined as:

the fraction 1/31,556,925.9747 of the tropical year for 1900 January 0 at 12 hours ephemeris time.

The current definition of the second, coupled with the current definition of the metre, is based on the special theory of relativity, which affirms our space-time to be a Minkowski space.

World time

Time-keeping is so critical to the functioning of modern societies that it is coordinated at an international level. The basis for scientific time is a continuous count of seconds based on atomic clocks around the world, known as the International Atomic Time (TAI). Other scientific time standards include Terrestrial Time and Barycentric Dynamical Time.

Coordinated Universal Time (UTC) is the basis for modern civil time. Since 1 January 1972, it has been defined to follow TAI with an exact offset of an integer number of seconds, changing only when a leap second is added to keep clock time synchronized with the rotation of the Earth. In TAI and UTC systems, the duration of a second is constant, as it is defined by the unchanging transition period of the caesium atom.

Greenwich Mean Time (GMT) is an older standard, adopted starting with British railways in 1847. Using telescopes instead of atomic clocks, GMT was calibrated to the mean solar time at the Royal Observatory, Greenwich in the UK. Universal Time (UT) is the modern term for the international telescope-based system, adopted to replace "Greenwich Mean Time" in 1928 by the International Astronomical Union. Observations at the Greenwich Observatory itself ceased in 1954, though the location is still used as the basis for the coordinate system. Because the rotational period of Earth is not perfectly constant, the duration of a second would vary if calibrated to a telescope-based standard like GMT or UT—in which a second was defined as a fraction of a day or year. The terms "GMT" and "Greenwich Mean Time" are sometimes used informally to refer to UT or UTC.

The Global Positioning System also broadcasts a very precise time signal worldwide, along with instructions for converting GPS time to UTC.

Earth is split up into a number of time zones. Most time zones are exactly one hour apart, and by convention compute their local time as an offset from UTC or GMT. In many locations these offsets vary twice yearly due to daylight saving time transitions.

Time conversions

These conversions are accurate at the millisecond level for time systems involving earth rotation (UT1 & TT). Conversions between atomic time systems (TAI, GPS, and UTC) are accurate at the microsecond level.

System	Description	UT1	UTC	TT	TAI	GPS
UT1	Mean Solar Time	UT1	UTC = UT1 - DUT1	TT = UT1 + 32.184 s + LS - DUT1	TAI = UT1 - DUT1 + LS	GPS = UT1 - DUT1 + LS - 19 s
UTC	Civil Time	UT1 = UTC + DUT1	UTC	TT = UTC + 32.184 s + LS	TAI = UTC + LS	GPS = UTC + LS - 19 s
TT	Terrestrial (Ephemeris) Time	UT1 = TT - 32.184 s - LS + DUT1	UTC = TT - 32.184 s - LS	TT	TAI = TT - 32.184 s	GPS = TT - 51.184 s
TAI	Atomic Time	UT1 = TAI + DUT1 - LS	UTC = TAI - LS	TT = TAI + 32.184 s	TAI	GPS = TAI - 19 s
GPS	GPS Time	UT1 = GPS + DUT1 - LS + 19 s	UTC = GPS - LS + 19 s	TT = GPS + 51.184 s	TAI = GPS + 19 s	GPS

Definitions:

1. LS = TAI - UTC = Leap Seconds from http://maia.usno.navy.mil/ser7/tai-utc.dat
2. DUT1 = UT1 - UTC from http://maia.usno.navy.mil/ser7/ser7.dat or http://maia.usno.navy.mil/search/search.html

Sidereal time

Sidereal time is the measurement of time relative to a distant star (instead of solar time that is relative to the sun). It is used in astronomy to predict when a star will be overhead. Due to the orbit of the earth around the sun a sidereal day is 4 minutes (1/366th) less than a solar day.

Chronology

Main article: Chronology

Another form of time measurement consists of studying the past. Events in the past can be ordered in a sequence (creating a chronology), and can be put into chronological groups (periodization). One of the most important systems of periodization is geologic time, which is a system of periodizing the events that shaped the Earth and its life. Chronology, periodization, and interpretation of the past are together known as the study of history.

Religion

Hindu units of time shown logarithmically

Further information: Time and fate deities

Linear and cyclical time

See also: Time Cycles and Wheel of time

Ancient cultures such as Incan, Mayan, Hopi, and other Native American Tribes, plus the Babylonians, Ancient Greeks, Hinduism, Buddhism, Jainism, and others have a concept of a wheel of time, that regards time as cyclical and quantic consisting of repeating ages that happen to every being of the Universe between birth and extinction.

In general, the Judaeo-Christian concept, based on the Bible, is that time is linear, beginning with the act of creation by God. The general Christian view is that time will end with the end of the world.

In the Old Testament book Ecclesiastes, traditionally ascribed to Solomon (970–928 BC), time (as the Hebrew word עדן, זמן `iddan(time) zĕman(season) is often translated) was traditionally regarded as a medium for the passage of predestined events. (Another word, زمان" זמן" zman, was current as meaning time fit for an event, and is used as the modern Arabic, Persian, and Hebrew equivalent to the English word "time".)

There is an appointed time (zman) for everything. And there is a time (’êth) for every event under heaven–
A time (’êth) to give birth, and a time to die; A time to plant, and a time to uproot what is planted.
A time to kill, and a time to heal; A time to tear down, and a time to build up.
A time to weep, and a time to laugh; A time to mourn, and a time to dance.
A time to throw stones, and a time to gather stones; A time to embrace, and a time to shun embracing.
A time to search, and a time to give up as lost; A time to keep, and a time to throw away.
A time to tear apart, and a time to sew together; A time to be silent, and a time to speak.
A time to love, and a time to hate; A time for war, and a time for peace. – Ecclesiastes 3:1–8

Time in Greek mythology

The Greek language denotes two distinct principles, Chronos and Kairos. The former refers to numeric, or chronological, time. The latter, literally "the right or opportune moment", relates specifically to metaphysical or Divine time. In theology, Kairos is qualitative, as opposed to quantitative.

In Greek mythology, Chronos (Ancient Greek: Χρόνος) is identified as the Personification of Time. His name in Greek means "time" and is alternatively spelled Chronus (Latin spelling) or Khronos. Chronos is usually portrayed as an old, wise man with a long, gray beard, such as "Father Time". Some English words whose etymological root is khronos/chronos include chronology, chronometer, chronic, anachronism, synchronize, and chronicle.

Philosophy

Main articles: Philosophy of space and time and Temporal finitism

Two distinct viewpoints on time divide many prominent philosophers. One view is that time is part of the fundamental structure of the universe, a dimension in which events occur in sequence. Sir Isaac Newton subscribed to this realist view, and hence it is sometimes referred to as Newtonian time. An opposing view is that time does not refer to any kind of actually existing dimension that events and objects "move through", nor to any entity that "flows", but that it is instead an intellectual concept (together with space and number) that enables humans to sequence and compare events This second view, in the tradition of Gottfried Leibniz and Immanuel Kant, holds that space and time "do not exist in and of themselves, but ... are the product of the way we represent things", because we can know objects only as they appear to us.

The Vedas, the earliest texts on Indian philosophy and Hindu philosophy dating back to the late 2nd millennium BC, describe ancient Hindu cosmology, in which the universe goes through repeated cycles of creation, destruction and rebirth, with each cycle lasting 4320 million years. Ancient Greek philosophers, including Parmenides and Heraclitus, wrote essays on the nature of time. Plato, in the Timaeus, identified time with the period of motion of the heavenly bodies. Aristotle, in Book IV of his Physica defined time as the number of change with respect to before and after.

In Book 11 of his Confessions, St. Augustine of Hippo ruminates on the nature of time, asking, "What then is time? If no one asks me, I know: if I wish to explain it to one that asketh, I know not." He begins to define time by what it is not rather than what it is, an approach similar to that taken in other negative definitions. However, Augustine ends up calling time a “distention” of the mind (Confessions 11.26) by which we simultaneously grasp the past in memory, the present by attention, and the future by expectation.

In contrast to ancient Greek philosophers who believed that the universe had an infinite past with no beginning, medieval philosophers and theologians developed the concept of the universe having a finite past with a beginning. This view is shared by Abrahamic faiths as they believe time started by creation, therefore the only thing being infinite is God and everything else, including time, is finite.

Isaac Newton believed in absolute space and absolute time; Leibniz believed that time and space are relational. The differences between Leibniz's and Newton's interpretations came to a head in the famous Leibniz-Clarke Correspondence.

Time is not an empirical concept. For neither co-existence nor succession would be perceived by us, if the representation of time did not exist as a foundation a priori. Without this presupposition we could not represent to ourselves that things exist together at one and the same time, or at different times, that is, contemporaneously, or in succession.

“

”

Immanuel Kant, Critique of Pure Reason (1781), trans. Vasilis Politis (London: Dent., 1991), p.54.

Immanuel Kant, in the Critique of Pure Reason, described time as an a priori intuition that allows us (together with the other a priori intuition, space) to comprehend sense experience. With Kant, neither space nor time are conceived as substances, but rather both are elements of a systematic mental framework that necessarily structures the experiences of any rational agent, or observing subject. Kant thought of time as a fundamental part of an abstract conceptual framework, together with space and number, within which we sequence events, quantify their duration, and compare the motions of objects. In this view, time does not refer to any kind of entity that "flows," that objects "move through," or that is a "container" for events. Spatial measurements are used to quantify the extent of and distances between objects, and temporal measurements are used to quantify the durations of and between events. (See Ontology).

Henri Bergson believed that time was neither a real homogeneous medium nor a mental construct, but possesses what he referred to as Duration. Duration, in Bergson's view, was creativity and memory as an essential component of reality.

According to Martin Heidegger we do not exist inside time, we are time. Hence, the relationship to the past is a present awareness of having been, which allows the past to exist in the present. The relationship to the future is the state of anticipating a potential possibility, task, or engagement. It is related to the human propensity for caring and being concerned, which causes "being ahead of oneself" when thinking of a pending occurrence. Therefore, this concern for a potential occurrence also allows the future to exist in the present. The present becomes an experience, which is qualitative instead of quantitative. Heidegger seems to think this is the way that a linear relationship with time, or temporal existence, is broken or transcended. We are not stuck in sequential time. We are able to remember the past and project into the future - we have a kind of random access to our representation of temporal existence --- we can, in our thoughts, step out of (ecstasis) sequential time.

Time as "unreal"

In 5th century BC Greece, Antiphon the Sophist, in a fragment preserved from his chief work On Truth, held that: "Time is not a reality (hypostasis), but a concept (noêma) or a measure (metron)." Parmenides went further, maintaining that time, motion, and change were illusions, leading to the paradoxes of his follower Zeno. Time as an illusion is also a common theme in Buddhist thought.

J. M. E. McTaggart's 1908 The Unreality of Time argues that, since every event has the characteristic of being both present and not present (i.e., future or past), that time is a self-contradictory idea (see also The flow of time).

These arguments often center around what it means for something to be unreal. Modern physicists generally believe that time is as real as space—though others, such as Julian Barbour in his book The End of Time, argue that quantum equations of the universe take their true form when expressed in the timeless realm containing every possible now or momentary configuration of the universe, called 'platonia' by Barbour. (See also: Eternalism (philosophy of time))

Physical definition

Classical mechanics
History of classical mechanics Timeline of classical mechanics
Branches Statics Dynamics / Kinetics Kinematics Applied mechanics Celestial mechanics Continuum mechanics Statistical mechanics
Formulations Newtonian mechanics (Vectorial mechanics) Analytical mechanics: Lagrangian mechanics Hamiltonian mechanics
Fundamental concepts Space Time Mass Inertia Velocity Speed Acceleration Force Momentum Impulse Torque / Moment / Couple Angular momentum Moment of inertia Reference frame Energy Kinetic energy Potential energy Mechanical work Mechanical power Virtual work D'Alembert's principle
Core topics Rigid body Rigid body dynamics Euler's equations (rigid body dynamics) Motion Linear motion Newton's laws of motion Newton's law of universal gravitation Euler's laws of motion Equations of motion Inertial frame of reference Non-inertial reference frame Fictitious force Mechanics of planar particle motion Displacement (vector) Relative velocity Friction Simple harmonic motion Harmonic oscillator Vibration Damping Damping ratio Rotational motion Circular motion Uniform circular motion Non-uniform circular motion Rotating reference frame Centripetal force Centrifugal force Centrifugal force (rotating reference frame) Reactive centrifugal force Coriolis force Pendulum Tangential speed Rotational speed Angular acceleration Angular velocity Angular frequency Angular displacement
Scientists Galileo Newton Kepler Horrocks Halley Euler d'Alembert Clairaut Lagrange Laplace Hamilton Poisson Daniel Bernoulli Johann Bernoulli Cauchy

Main article: Time in physics

From the age of Newton to Einstein's profound reinterpretation of the physical concepts associated with time and space, time was considered absolute and to flow equably (to use Newton's words) for all observers. Non-relativistic classical mechanics is based on this Newtonian idea of time.

Einstein, in his special theory of relativity, postulated the constancy and finiteness of the speed of light for all observers. He showed that this postulate, together with a reasonable definition for what it means for two events to be simultaneous, requires that distances appear compressed and time intervals appear lengthened for events associated with objects in motion relative to an inertial observer.

The theory of special relativity finds a convenient formulation in Minkowski spacetime, a mathematical structure that combines three dimensions of space with a single dimension of time. In this formalism, distances in space can be measured by how long light takes to travel that distance, e.g., a light-year is a measure of distance, and a meter is now defined in terms of how far light travels in a certain amount of time. Two events in Minkowski spacetime are separated by an invariant interval, which can be either space-like, light-like, or time-like. Events that are time-like cannot be simultaneous in any frame of reference, there must be a temporal component (and possibly a spatial one) to their separation. Events that are space-like could be simultaneous in some frame of reference, and there is no frame of reference in which they do not have a spatial separation. People travelling at different velocities between two events measure different spatial and temporal separations between the events, but the invariant interval is constant and independent of velocity.

Classical mechanics

In non-relativistic classical mechanics, Newton's concept of "relative, apparent, and common time" can be used in the formulation of a prescription for the synchronization of clocks. Events seen by two different observers in motion relative to each other produce a mathematical concept of time that works sufficiently well for describing the everyday phenomena of most people's experience. In the late nineteenth century, physicists encountered problems with the classical understanding of time, in connection with the behaviour of electricity and magnetism. Einstein resolved these problems by invoking a method of synchronizing clocks using the constant, finite speed of light as the maximum signal velocity. This led directly to the result that observers in motion relative to one another measure different elapsed times for the same event.

Two-dimensional space depicted in three-dimensional spacetime. The past and future light cones are absolute, the "present" is a relative concept different for observers in relative motion.

Spacetime

Main article: Spacetime

Time has historically been closely related with space, the two together comprising spacetime in Einstein's special relativity and general relativity. According to these theories, the concept of time depends on the spatial reference frame of the observer, and the human perception as well as the measurement by instruments such as clocks are different for observers in relative motion. In other words, if someone is flying in something that moves at the speed of light with a clock they do not notice a shift in time and see themselves as stationary because everything traveling at that speed slows down at the same rate (including the clock, the person's thought process, and the functions performed by their body). If there is an observer watching the other one travel, the person who is traveling at light speed begins to distort. However, for the person traveling, everything outside is shrunken down instead because they go around the earth's surface quickly and since everything is slower traveling can be done in shorter amount of time without the person noticing their timeframe has shifted. What seems like seconds for them can be hundreds of years for a person living in real time. Both times are correct for each person because the time is dependent on how fast you are traveling. However, the definition of each tense remains the same, the past is the set of events that can send light signals to the observer and the future is the set of events to which the observer can send light signals.

Time dilation

Relativity of simultaneity: Event B is simultaneous with A in the green reference frame, but it occurred before in the blue frame, and occurs later in the red frame.

Main article: Time dilation

Einstein showed in his thought experiments that people travelling at different speeds, while agreeing on cause and effect, measures different time separations between events, and can even observe different chronological orderings between non-causally related events. Though these effects are typically minute in the human experience, the effect becomes much more pronounced for objects moving at speeds approaching the speed of light. Many subatomic particles exist for only a fixed fraction of a second in a lab relatively at rest, but some that travel close to the speed of light can be measured to travel farther and survive much longer than expected (a muon is one example). According to the special theory of relativity, in the high-speed particle's frame of reference, it exists, on the average, for a standard amount of time known as its mean lifetime, and the distance it travels in that time is zero, because its velocity is zero. Relative to a frame of reference at rest, time seems to "slow down" for the particle. Relative to the high-speed particle, distances seem to shorten. Einstein showed how both temporal and spatial dimensions can be altered (or "warped") by high-speed motion.

Einstein (The Meaning of Relativity): "Two events taking place at the points A and B of a system K are simultaneous if they appear at the same instant when observed from the middle point, M, of the interval AB. Time is then defined as the ensemble of the indications of similar clocks, at rest relatively to K, which register the same simultaneously."

Einstein wrote in his book, Relativity, that simultaneity is also relative, i.e., two events that appear simultaneous to an observer in a particular inertial reference frame need not be judged as simultaneous by a second observer in a different inertial frame of reference.

Relativistic time versus Newtonian time

Views of spacetime along the world line of a rapidly accelerating observer in a relativistic universe. The events ("dots") that pass the two diagonal lines in the bottom half of the image (the past light cone of the observer in the origin) are the events visible to the observer.

The animations visualise the different treatments of time in the Newtonian and the relativistic descriptions. At the heart of these differences are the Galilean and Lorentz transformations applicable in the Newtonian and relativistic theories, respectively.

In the figures, the vertical direction indicates time. The horizontal direction indicates distance (only one spatial dimension is taken into account), and the thick dashed curve is the spacetime trajectory ("world line") of the observer. The small dots indicate specific (past and future) events in spacetime.

The slope of the world line (deviation from being vertical) gives the relative velocity to the observer. Note how in both pictures the view of spacetime changes when the observer accelerates.

In the Newtonian description these changes are such that time is absolute: the movements of the observer do not influence whether an event occurs in the 'now' (i.e., whether an event passes the horizontal line through the observer).

However, in the relativistic description the observability of events is absolute: the movements of the observer do not influence whether an event passes the "light cone" of the observer. Notice that with the change from a Newtonian to a relativistic description, the concept of absolute time is no longer applicable: events move up-and-down in the figure depending on the acceleration of the observer.

Arrow of time

Main article: Arrow of time

Time appears to have a direction – the past lies behind, fixed and immutable, while the future lies ahead and is not necessarily fixed. Yet for the most part the laws of physics do not specify an arrow of time, and allow any process to proceed both forward and in reverse. This is generally a consequence of time being modeled by a parameter in the system being analyzed, where there is no "proper time": the direction of the arrow of time is sometimes arbitrary. Examples of this include the Second law of thermodynamics, which states that entropy must increase over time (see Entropy); the cosmological arrow of time, which points away from the Big Bang, CPT symmetry, and the radiative arrow of time, caused by light only traveling forwards in time (see light cone). In particle physics, the violation of CP symmetry implies that there should be a small counterbalancing time asymmetry to preserve CPT symmetry as stated above. The standard description of measurement in quantum mechanics is also time asymmetric (see Measurement in quantum mechanics).

Quantised time

See also: Chronon

Time quantization is a hypothetical concept. In the modern established physical theories (the Standard Model of Particles and Interactions and General Relativity) time is not quantized.

Planck time (~ 5.4 × 10⁻⁴⁴ seconds) is the unit of time in the system of natural units known as Planck units. Current established physical theories are believed to fail at this time scale, and many physicists expect that the Planck time might be the smallest unit of time that could ever be measured, even in principle. Tentative physical theories that describe this time scale exist; see for instance loop quantum gravity.

Time and the Big Bang

Stephen Hawking in particular has addressed a connection between time and the Big Bang. In A Brief History of Time and elsewhere, Hawking says that even if time did not begin with the Big Bang and there were another time frame before the Big Bang, no information from events then would be accessible to us, and nothing that happened then would have any effect upon the present time-frame. Upon occasion, Hawking has stated that time actually began with the Big Bang, and that questions about what happened before the Big Bang are meaningless. This less-nuanced, but commonly repeated formulation has received criticisms from philosophers such as Aristotelian philosopher Mortimer J. Adler.

Scientists have come to some agreement on descriptions of events that happened 10⁻³⁵ seconds after the Big Bang, but generally agree that descriptions about what happened before one Planck time (5 × 10⁻⁴⁴ seconds) after the Big Bang are likely to remain pure speculation.

Speculative physics beyond the Big Bang

A graphical representation of the expansion of the universe with the inflationary epoch represented as the dramatic expansion of the metric seen on the left.

While the Big Bang model is well established in cosmology, it is likely to be refined in the future. Little is known about the earliest moments of the universe's history. The Penrose-Hawking singularity theorems require the existence of a singularity at the beginning of cosmic time. However, these theorems assume that general relativity is correct, but general relativity must break down before the universe reaches the Planck temperature, and a correct treatment of quantum gravity may avoid the singularity.

There may also be parts of the universe well beyond what can be observed in principle. If inflation occurred this is likely, for exponential expansion would push large regions of space beyond our observable horizon.

Some proposals, each of which entails untested hypotheses, are:

• models including the Hartle–Hawking boundary condition in which the whole of space-time is finite; the Big Bang does represent the limit of time, but without the need for a singularity.
• brane cosmology models in which inflation is due to the movement of branes in string theory; the pre-big bang model; the ekpyrotic model, in which the Big Bang is the result of a collision between branes; and the cyclic model, a variant of the ekpyrotic model in which collisions occur periodically.
• chaotic inflation, in which inflation events start here and there in a random quantum-gravity foam, each leading to a bubble universe expanding from its own big bang.

Proposals in the last two categories see the Big Bang as an event in a much larger and older universe, or multiverse, and not the literal beginning.

Time travel

Main article: Time travel

See also: Time travel in fiction, Wormhole, and Twin paradox

Time travel is the concept of moving backwards and/or forwards to different points in time, in a manner analogous to moving through space, and different from the normal "flow" of time to an earthbound observer. In this view, all points in time (including future times) "persist" in some way. Time travel has been a plot device in fiction since the 19th century. Traveling backwards in time has never been verified, presents many theoretic problems, and may be an impossibility. Any technological device, whether fictional or hypothetical, that is used to achieve time travel is known as a time machine.

A central problem with time travel to the past is the violation of causality; should an effect precede its cause, it would give rise to the possibility of a temporal paradox. Some interpretations of time travel resolve this by accepting the possibility of travel between branch points, parallel realities, or universes.

Another solution to the problem of causality-based temporal paradoxes is that such paradoxes cannot arise simply because they have not arisen. As illustrated in numerous works of fiction, free will either ceases to exist in the past or the outcomes of such decisions are predetermined. As such, it would not be possible to enact the grandfather paradox because it is a historical fact that your grandfather was not killed before his child (your parent) was conceived. This view doesn't simply hold that history is an unchangeable constant, but that any change made by a hypothetical future time traveler would already have happened in his or her past, resulting in the reality that the traveler moves from. More elaboration on this view can be found in the Novikov self-consistency principle.

Judgment of time

Main article: Time perception

The specious present refers to the time duration wherein one's perceptions are considered to be in the present. The experienced present is said to be ‘specious’ in that, unlike the objective present, it is an interval and not a durationless instant. The term specious present was first introduced by the psychologist E.R. Clay, and later developed by William James.

Biopsychology

The brain's judgement of time is known to be a highly distributed system, including at least the cerebral cortex, cerebellum and basal ganglia as its components. One particular component, the suprachiasmatic nuclei, is responsible for the circadian (or daily) rhythm, while other cell clusters appear capable of shorter-range (ultradian) timekeeping.

Psychoactive drugs can impair the judgement of time. Stimulants can lead both humans and rats to overestimate time intervals, while depressants can have the opposite effect. The level of activity in the brain of neurotransmitters such as dopamine and norepinephrine may be the reason for this. Such chemicals will either excite or inhibit the firing of neurons in the brain, with a greater firing rate allowing the brain to register the occurrence of more events within a given interval (speed up time) and a decreased firing rate reducing the brain's capacity to distinguish events occurring within a given interval (slow down time).

Mental chronometry is the use of response time in perceptual-motor tasks to infer the content, duration, and temporal sequencing of cognitive operations.

Alterations

In addition to psychoactive drugs, judgements of time can be altered by temporal illusions (like the kappa effect ), age, and hypnosis. The sense of time is impaired in some people with neurological diseases such as Parkinson's disease and attention deficit disorder.

Psychologists assert that time seems to go faster with age, but the literature on this age-related perception of time remains controversial. Those who support this notion point to the increased pressence of exciatory neurotransmitters in young people and the role having new experiences plays in time perception.

Use of time

See also: Time management and Time discipline

In sociology and anthropology, time discipline is the general name given to social and economic rules, conventions, customs, and expectations governing the measurement of time, the social currency and awareness of time measurements, and people's expectations concerning the observance of these customs by others. Arlie Russell Hochschild and Norbert Elias have written on the use of time from a sociological perspective.

The use of time is an important issue in understanding human behaviour, education, and travel behaviour. Time use research is a developing field of study. The question concerns how time is allocated across a number of activities (such as time spent at home, at work, shopping, etc.). Time use changes with technology, as the television or the Internet created new opportunities to use time in different ways. However, some aspects of time use are relatively stable over long periods of time, such as the amount of time spent traveling to work, which despite major changes in transport, has been observed to be about 20–30 minutes one-way for a large number of cities over a long period.

Time management is the organization of tasks or events by first estimating how much time a task requires and when it must be completed, and adjusting events that would interfere with its completion so it is done in the appropriate amount of time. Calendars and day planners are common examples of time management tools.

A sequence of events, or series of events, is a sequence of items, facts, events, actions, changes, or procedural steps, arranged in time order (chronological order), often with causality relationships among the items. Because of causality, cause precedes effect, or cause and effect may appear together in a single item, but effect never precedes cause. A sequence of events can be presented in text, tables, charts, or timelines. The description of the items or events may include a timestamp. A sequence of events that includes the time along with place or location information to describe a sequential path may be referred to as a world line.

Uses of a sequence of events include stories, historical events (chronology), directions and steps in procedures, and timetables for scheduling activities. A sequence of events may also be used to help describe processes in science, technology, and medicine. A sequence of events may be focused on past events (e.g., stories, history, chronology), on future events that must be in a predetermined order (e.g., plans, schedules, procedures, timetables), or focused on the observation of past events with the expectation that the events will occur in the future (e.g., processes). The use of a sequence of events occurs in fields as diverse as machines (cam timer), documentaries (Seconds From Disaster), law (choice of law), computer simulation (discrete event simulation), and electric power transmission (sequence of events recorder). A specific example of a sequence of events is the timeline of the Fukushima Daiichi nuclear disaster.

See also

Time's mortal aspect is personified in this bronze statue by Charles van der Stappen

• Horology
• Kairos
• Term (time)

Books

• A Brief History of Time by Stephen Hawking
• About Time: Einstein's Unfinished Revolution by Paul Davies
• From Eternity to Here: The Quest for the Ultimate Theory of Time by Sean M. Carroll
• The Physical Basis of The Direction of Time by Heinz-Dieter Zeh
• An Experiment with Time by J. W. Dunne
• Einstein's Dreams by Alan Lightman

Organizations

Leading scholarly organizations for researchers on the history and technology of time and timekeeping

• Antiquarian Horological Society – AHS (United Kingdom)
• Chronometrophilia (Switzerland)
• Deutsche Gesellschaft für Chronometrie – DGC (Germany)
• National Association of Watch and Clock Collectors - NAWCC (United States of America)

Miscellaneous arts and sciences

• Anachronistic
• Date and time notation by country
• List of cycles
• Network Time Protocol (NTP)
• Nonlinear (arts)
• Philosophy of physics
• Rate (mathematics)

Miscellaneous units of time

• Fiscal year
• Half-life
• Hexadecimal time
• Season
• Tithi
• Unit of time
• Unix epoch

References

Further reading

• Barbour, Julian (1999). The End of Time: The Next Revolution in Our Understanding of the Universe. Oxford University Press. ISBN 0-19-514592-5.
• Landes, David (2000). Revolution in Time. Harvard University Press. ISBN 0-674-00282-2.
• Das, Tushar Kanti (1990). The Time Dimension: An Interdisciplinary Guide. New York: Praeger. ISBN 0-275-92681-8.- Research bibliography
• Davies, Paul (1996). About Time: Einstein's Unfinished Revolution. New York: Simon & Schuster Paperbacks. ISBN 0-684-81822-1.
• Feynman, Richard (1994) [1965]. The Character of Physical Law. Cambridge (Mass): The MIT Press. pp. 108–126. ISBN 0-262-56003-8. http://mitpress.mit.edu/catalog/item/default.asp?ttype=2&tid=5277.
• Galison, Peter (1992). Einstein's Clocks and Poincaré's Maps: Empires of Time. New York: W. W. Norton. ISBN 0-393-02001-0.
• Highfield, Roger (1992). Arrow of Time: A Voyage through Science to Solve Time's Greatest Mystery. Random House. ISBN 0-449-90723-6.
• Mermin, N. David (2005). It's About Time: Understanding Einstein's Relativity. Princeton University Press. ISBN 0-691-12201-6. http://press.princeton.edu/titles/8112.html.
• Penrose, Roger (1999) [1989]. The Emperor's New Mind: Concerning Computers, Minds, and the Laws of Physics. New York: Oxford University Press. pp. 391–417. ISBN 0-19-286198-0. http://ukcatalogue.oup.com/product/9780192861986.do. Retrieved 2011-04-09.
• Price, Huw (1996). Time's Arrow and Archimedes' Point. Oxford University Press. ISBN 0-19-511798-0. http://sydney.edu.au/time/price/TAAP.html. Retrieved 2011-04-09.
• Reichenbach, Hans (1999) [1956]. The Direction of Time. New York: Dover. ISBN 0-486-40926-0. http://store.doverpublications.com/0486409260.html.
• Stiegler, Bernard, Technics and Time, 1: The Fault of Epimetheus
• Quznetsov, Gunn A. (2006). Logical Foundation of Theoretical Physics. Nova Sci. Publ.. ISBN 1-59454-948-6.
• Whitrow, Gerald J. (1973). The Nature of Time. Holt, Rinehart and Wilson (New York).
• Whitrow, Gerald J. (1980). The Natural Philosophy of Time. Clarendon Press (Oxford).
• Whitrow, Gerald J. (1988). Time in History. The evolution of our general awareness of time and temporal perspective. Oxford University Press. ISBN 0-19-285211-6.
• Rovelli, Carlo (2006). What is time? What is space?. Rome: Di Renzo Editore. ISBN 88-8323-146-5. http://www.direnzo.it/main.phtml?Language=en&Doc=0001&ISBN=8883231465.
• Charlie Gere, (2005) Art, Time and Technology: Histories of the Disappearing Body, Berg
• Craig Callendar, Introducing Time, Icon Books, 2010, ISBN 978-1848311206
• Benjamin Gal-Or, Cosmology, Physics and Philosophy, Springer Verlag, 1981, 1983, 1987, ISBN 0-387-90581-2, ISBN 0-387-96526-2.

External links

• Exploring Time from Planck Time to the lifespan of the universe
• Different systems of measuring time
• Time on In Our Time at the BBC. (listen now)

• Dowden, Bradley (California State University, Sacramento) (2007). "Time". In James Fieser, PhD, Bradley Dowden, PhD. The Internet Encyclopedia of Philosophy. http://www.iep.utm.edu/time/. Retrieved 2011-04-09.
• Le Poidevin, Robin (Winter 2004). "The Experience and Perception of Time". In Edward N. Zalta. The Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/archives/win2004/entries/time-experience. Retrieved 2011-04-09.
• Time at Open Directory

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• 5. ST上昇型心筋梗塞におけるプライマリ経皮的冠動脈インターベンション：転帰の決定因子 primary percutaneous coronary intervention in acute st elevation myocardial infarction determinants of outcome

English Journal

• Glucocorticoids predict 10-year fragility fracture risk in a population-based ambulatory cohort of men and women: Canadian Multicentre Osteoporosis Study (CaMos).

• Ioannidis G1, Pallan S, Papaioannou A, Mulgund M, Rios L, Ma J, Thabane L, Davison KS, Josse RG, Kovacs CS, Kreiger N, Olszynski WP, Prior JC, Towheed T, Adachi JD; CaMos Research Group.Author information 1Faculty of Medicine, McMaster University, Hamilton, ON, Canada, g.ioannidis@sympatico.ca.AbstractWe determined the prospective 10-year association among incident fragility fractures and four glucocorticoid (GC) treatment groups (Never GC, Prior GC, Baseline GC, and Ever GC). Results showed that GC treatment is associated with increased 10-year incident fracture risk in ambulatory men and women across Canada.
• Archives of osteoporosis.Arch Osteoporos.2014 Dec;9(1):169. doi: 10.1007/s11657-013-0169-5. Epub 2014 Feb 28.
• We determined the prospective 10-year association among incident fragility fractures and four glucocorticoid (GC) treatment groups (Never GC, Prior GC, Baseline GC, and Ever GC). Results showed that GC treatment is associated with increased 10-year incident fracture risk in ambulatory men and women
• PMID 24577853

• The clinical characteristics of patients with hip fractures in typical locations and atypical femoral fractures.

• Velasco S1, Kim S, Bleakney R, Jamal SA.Author information 1Unidad de Endocrinología, Clínica Alemana de Santiago, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago, Chile.AbstractThe pathophysiology of atypical fractures is unknown. We compared characteristics of patients with atypical femoral fractures and hip fractures in typical locations of the femur. Patients with atypical fracture reported a longer duration of use of bisphosphonates, had higher body mass index, and higher total hip bone mineral density. Further studies are needed.
• Archives of osteoporosis.Arch Osteoporos.2014 Dec;9(1):171. doi: 10.1007/s11657-014-0171-6. Epub 2014 Jan 31.
• The pathophysiology of atypical fractures is unknown. We compared characteristics of patients with atypical femoral fractures and hip fractures in typical locations of the femur. Patients with atypical fracture reported a longer duration of use of bisphosphonates, had higher body mass index, and hig
• PMID 24481776

• The incidence rate of hip fracture in Shiraz, Iran during 2008-2010.

• Maharlouei N1, Khodayari M, Forouzan F, Rezaianzadeh A, Lankarani KB.Author information 1Health Policy Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran.AbstractThis study aimed to estimate the incidence rate of hip fracture during 2008-2010 in Shiraz, Iran. Overall, the standardized age-related incidence were 329.6/100,000 in men and 1,589.7/100,000 in women. The incidence rate in females was remarkably higher than the previous studies in Iran.
• Archives of osteoporosis.Arch Osteoporos.2014 Dec;9(1):165. doi: 10.1007/s11657-013-0165-9. Epub 2014 Jan 15.
• This study aimed to estimate the incidence rate of hip fracture during 2008-2010 in Shiraz, Iran. Overall, the standardized age-related incidence were 329.6/100,000 in men and 1,589.7/100,000 in women. The incidence rate in females was remarkably higher than the previous studies in Iran.PURPOSE: Thi
• PMID 24424876

• The National Ambulatory Medical Care Survey: a resource for understanding the outpatient dermatology treatment.

• Ahn CS1, Allen MM, Davis SA, Huang KE, Fleischer AB Jr, Feldman SR.Author information 1Department of Dermatology and.AbstractBACKGROUND: The National Ambulatory Care Survey (NAMCS) collects information on outpatient medical care in the United States. Key characteristics of the NAMCS methodology are not well recognized. We describe the NAMCS survey design and patient visits to dermatologists and to present information on the validity of the NAMCS data by comparing key features of the dermatologist sample to other surveys of dermatologists.
• The Journal of dermatological treatment.J Dermatolog Treat.2014 Dec;25(6):453-8. doi: 10.3109/09546634.2014.858409. Epub 2013 Nov 21.
• BACKGROUND: The National Ambulatory Care Survey (NAMCS) collects information on outpatient medical care in the United States. Key characteristics of the NAMCS methodology are not well recognized. We describe the NAMCS survey design and patient visits to dermatologists and to present information on t
• PMID 24256113

Japanese Journal

• Graphene oxide captured for green use: Influence on the structures of calcium alginate and macroporous alginic beads and their application to aqueous removal of acridine orange

• Sun Ling,Fugetsu Bunshi
• Chemical Engineering Journal 240, 565-573, 2014-03-15
• … Kinetics studies exhibited the addition of GO resulted in adsorptions with shorter equilibrium time and faster initial adsorption rate, and the adsorbents with higher equilibrium capacities. …
• NAID 120005367404

• Hadoopを用いた衛星画像データ解析処理の高速化の研究

• 塚本 勢児,布広 永示
• 情報処理学会研究報告. [システムソフトウェアとオペレーティング・システム] 2014-OS-128(9), 1-6, 2014-02-27
• 東京情報大学では,学術フロンティアプロジェクトの一環として,NASA の衛星 Terra と Aqua に搭載されているセンサーで撮影された衛星画像データである MODIS データを受信し,大学や研究機関に提供している.現在,MODIS データを蓄積,解析する衛星画像データ解析処理システムを開発している.本研究では,衛星画像データ解析システムのデータ解析性能を向上するために,オープンソースソフトウ …
• NAID 110009675776

• On-The-Fly - Automated Storage Tiering (OTF-AST)の提案

• 大江 和一,岩田 聡,本田 岳夫,河場 基行
• 情報処理学会研究報告. [システムソフトウェアとオペレーティング・システム] 2014-OS-128(6), 1-10, 2014-02-27
• ストレージシステムのコストパフォーマンスを向上する目的で,SSD と HDD を組み合わせた階層ストレージシステムが提案されており,一定期間にアクセス頻度の高いデータを SSD に置くことで高速化を図る仕組みである.しかし,ファイル共有ストレージへのアクセスパターンにおいては,記憶領域の狭い範囲に数分から数十分間 IO が集中し,時間と共に別の領域に移動する特徴があるため,長い期間の頻度でデータを …
• NAID 110009675773

• 次元数の異なるアプリケーションに柔軟に適用可能な並列型ユークリッド距離検索連想メモリ

• 赤澤 智信,HansJurgenMattausch
• 情報処理学会研究報告. 計算機アーキテクチャ研究会報告 2014-ARC-209(6), 1-5, 2014-02-27
• 報告する次元数に対する柔軟性を有するデジタル並列型最小距離検索連想メモリは距離をクロック数に変換するデジタル時間領域アーキテクチャを用いる.本報告では次元数に対する柔軟性を向上させるために次元数拡張回路 DEC (Dimension Extension Circuit) を新たに適用した.コンセプト検証のために提案アーキテクチャを,180nmCMOS テクノロジを用いた 32 参照ベクトル,8 次 …
• NAID 110009675347

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★リンクテーブル★

リンク元	「phase」「時期」「duration」「期間」「in time」
拡張検索	「mean survival time」「isovolumic relaxation time」
関連記事	「timing」

「phase」

　　[★]

• n.

• 相、段階、時期、局面、位相、フェーズ

• v.

• 段階的に実行する

関

aspect、grade、period、phased、phasic、situation、stage、step、time

　 　 　 　 　 　 　

「時期」

　　[★]

英

• period、time、phase、stage

関

位相、期間、局面、時間、ステージ、相、段階、時、～倍の、段階的に実行する、フェーズ

「duration」

　　[★]

• n.

• 持続時間、持続期間、期間、持続

関

continuity、last、period、persist、persistence、sustain、term、time

　 　 　 　

「期間」

　　[★]

英

• period、term、duration、time

関

時間、時期、持続、持続時間、時、名付ける、用語、～倍の、持続期間

「in time」

　　[★]

• in time

• 間に合って、遅れずに、ちょうど良いときに
• いつかは、いずれは、そのうちに
• 調子を合わせて、正しいテンポで

関

time

「mean survival time」

　　[★]

• 平均生存時間

関

survival rate、survivorship

「isovolumic relaxation time」

　　[★]

同

IVRT, 等容弛緩時間

「timing」

　　[★]

• n.

• タイミング