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Minute

The minute is a unit of time equal to 60 seconds, representing one-sixtieth of an hour, and is accepted for use alongside the International System of Units (SI) despite the second being the SI base unit for time. It is also a unit of angle equal to one-sixtieth of a degree.^[1] This subdivision originates from the ancient Babylonian sexagesimal (base-60) numbering system, which influenced Greek astronomers like Ptolemy around 150 CE and persisted through medieval European timekeeping traditions.^[2] The term "minute" derives from the Medieval Latin minūta, short for pars minuta prima ("first small part"), reflecting its role as the initial subdivision of the hour into smaller portions.^[3] In modern contexts, the minute serves as a fundamental measure for short durations in daily life, scientific experiments, sports timing, and transportation schedules, with 1,440 minutes comprising a standard 24-hour day.^[4] The division into minutes was adopted with mechanical clocks beginning in the 14th century, with minute hands added in the 16th century, thereby standardizing time division and enabling precise coordination in navigation, industry, and global communication.^[5] While decimal time systems were briefly proposed during the French Revolution,^[6] the minute's sexagesimal structure remains dominant due to its mathematical convenience for fractions and compatibility with angular measurements in astronomy and geography, where degrees are divided into 60 arcminutes.

Definition and Etymology

Unit of Time

The minute is a unit of time equal to one sixtieth (1/60) of an hour.^[1] It is equivalent to 60 seconds and serves as a standard subdivision for measuring durations in everyday and scientific contexts.^[7] In the International System of Units (SI), the minute is one of the units accepted for use alongside the seven base units, with its exact duration defined as 60 seconds.^[8] The underlying second, the SI base unit of time, is defined by the fixed numerical value of the caesium-133 hyperfine transition frequency, ensuring the minute's precision and invariance.^[9] This atomic definition was established by the 13th General Conference on Weights and Measures (CGPM) in 1967, replacing earlier astronomical-based standards and providing a stable foundation for time measurement independent of Earth's rotation.^[10] The modern minute maintains a fixed duration, in contrast to ancient time units like the variable-length hours used in Egyptian systems, where divisions of the day adjusted seasonally.^[11] This constancy underpins its reliability in global standards, distinguishing it from the minute of arc in angular measurement, which divides the degree into sixtieths but relates analogously to the sexagesimal system without temporal equivalence.^[1]

Unit of Angle

In angular measurement, the minute of arc, commonly referred to as the arcminute, is defined as one-sixtieth (1/60) of a degree. This unit, symbolized by a single prime (′), provides a subdivision of the degree for expressing finer angular resolutions beyond whole degrees. It forms part of the sexagesimal system inherited from ancient Babylonian mathematics, where angles are divided into 60 parts for precision in calculations.^[12] Relative to a complete circle, which spans 360 degrees, there are 21,600 arcminutes, calculated as 360 × 60.^[13] This relation underscores the arcminute's role in quantifying small portions of circular geometry, where it represents 1/21,600 of the full 360° turn.^[14] In standard notation, angular measurements using arcminutes follow the convention of degrees° minutes' seconds″, ensuring clarity in technical documentation.^[15] The arcminute finds primary application in fields requiring precise directional measurements, such as navigation and astronomy, where it denotes small angular separations or positions on the celestial sphere. For instance, in celestial navigation, coordinates like latitude and longitude are often specified to the arcminute for determining positions at sea. In astronomy, it measures the apparent diameters of objects, such as the Moon's roughly 30′ width, or the resolution limits of telescopes.^[16] Although a homonym of the temporal minute used for time duration, the arcminute operates independently in geometric and spatial contexts, including surveying where it helps define boundaries and alignments with high accuracy.^[17]

Linguistic Origins

The term "minute" as a unit of time derives from the Latin minuta, meaning "small" or "minute thing," specifically from the Medieval Latin phrase pars minuta prima, or "first small part," which referred to the first subdivision of an hour or degree into sixtieth parts.^[3]^[18] This nomenclature originated in astronomical and mathematical contexts, where Ptolemy and later scholars used it to denote the sixtieth part of a circle or temporal hour, emphasizing its role as a diminished portion.^[3] In English, the word entered as "minute" around the late 14th century, borrowed from Middle French minute, which itself stemmed from Medieval Latin minūta.^[19] Earlier attestations appear in Anglo-French by the early 13th century, reflecting the influence of Old French minuce or minute during the Norman period, when French terminology permeated Middle English scientific and administrative language.^[3] The related term "second" follows a parallel pattern, deriving from pars minuta secunda, or "second small part," indicating the next subdivision of the minute into sixtieths, as established in Medieval Latin astronomical texts.^[20] This sequential naming highlights the hierarchical division of time units from larger to smaller portions. Internationally, cognates preserve this Latin root: Spanish minuto traces directly from Latin minūta via Old Spanish, denoting the same temporal unit, while German Minute is borrowed from French minute or Medieval Latin, maintaining the sense of a "small part" in both time and angular measurement.^[21]^[22] (Note: Wiktionary used here for language-specific etymology, as it aggregates dictionary data.) The adjective "minute," meaning very small or precise, shares the same Latin origin in minūtus, the past participle of minuō ("to lessen"), underscoring how the unit's etymology ties to concepts of diminution across both temporal and descriptive uses.^[3]

Historical Development

Ancient Origins

The concept of the minute as a subdivision of time and angle emerged in ancient Mesopotamia with the development of the sexagesimal (base-60) system by the Sumerians around 2000 BCE, which the Babylonians later refined for astronomical and calendrical purposes.^[23] This system divided the full circle into 360 parts (degrees) and the hour into 60 smaller units, laying the foundational structure for minutes in both angular measurement and timekeeping, as evidenced in Babylonian astronomical tablets that subdivided temporal units for tracking celestial events.^[24] In parallel, ancient Egyptian and Sumerian civilizations employed water clocks, or clepsydrae, by approximately 1500 BCE to approximate intervals akin to minutes within their unequal hourly divisions of the day and night.^[25] These devices, such as the outflow clepsydra found in Egyptian tombs from the 15th century BCE, regulated water flow to mark shorter periods during nighttime watches or ritual timings, though their precision was limited by factors like temperature affecting flow rates.^[26] Sumerian examples, referenced in cuneiform texts, similarly used clepsydrae to segment the night into 12 parts, facilitating practical divisions smaller than hours for administrative and astronomical observations.^[27] The Greeks adopted and adapted these Babylonian subdivisions in the 2nd century BCE, particularly through the work of astronomer Hipparchus of Nicaea, who employed arcminutes—60ths of a degree—in his influential table of chords for calculating celestial positions and distances.^[28] Hipparchus integrated sexagesimal fractions into Greek astronomy to express precise angular measurements, such as stellar longitudes, enhancing predictive models for eclipses and planetary motions.^[29] However, ancient minutes were not fixed in duration as in modern systems; they varied seasonally due to the use of temporal hours, where daylight and nighttime were each divided into 12 unequal parts that lengthened or shortened with changing day lengths.^[30] In Babylonian and Egyptian practices, this resulted in summer daytime "minutes" being shorter than winter ones, reflecting a practical adaptation to solar cycles rather than uniform intervals.^[31] Greek astronomers like Hipparchus acknowledged this variability but began shifting toward equinoctial (fixed) hours for greater consistency in calculations.^[32]

Medieval and Early Modern Standardization

In the Islamic Golden Age, the 11th-century Persian polymath Al-Biruni advanced the application of sexagesimal divisions to time measurement in astronomy, explicitly subdividing the hour into 60 minutes, 60 seconds, and further smaller units like thirds and fourths when tabulating lunar phases and other celestial events. This refinement built on earlier Babylonian and Ptolemaic angular systems but marked the first systematic use of minutes and seconds for temporal calculations, facilitating precise astronomical predictions.^[5] In medieval Europe, this knowledge spread through translations of Arabic texts via the Iberian Peninsula starting in the 12th century, influencing scholars who began applying sexagesimal units to time. By the 13th century, figures like the English philosopher Roger Bacon referenced minute divisions in discussions of time and motion, though practical daily use remained limited. The introduction of mechanical clocks in European monasteries around the late 13th and early 14th centuries, such as those in Milan and Strasbourg, enabled more regular division of the canonical hours—the eight prayer periods structuring monastic life—initially into quarters but increasingly toward finer subdivisions approximating minutes as escapement mechanisms improved accuracy.^[5]^[33] During the 15th century, the German astronomer Regiomontanus (Johannes Müller) further standardized the minute in angular measurements through his ephemerides and trigonometric tables, which provided planetary positions to arcminutes for navigational purposes; these works, published posthumously in 1474, were instrumental in enabling transoceanic voyages by improving latitude calculations at sea.^[34] By the 16th century, the transition from unequal (seasonal) hours—where daytime and nighttime were each divided into 12 variable parts—to equinoctial (equal) hours and minutes gained momentum, driven by widespread adoption of mechanical clocks in urban centers and the demands of commerce and exploration; this shift solidified the minute as a fixed unit of 1/60 hour, independent of solar variations.^[35]

Modern Adoption and Reforms

The International Meridian Conference, convened in Washington, D.C., from October 1 to November 1, 1884, marked a significant step in global time standardization by establishing Greenwich Mean Time (GMT) as the international reference meridian. Attended by representatives from 25 nations, the conference adopted Resolution 4, which defined the universal day as the mean solar day beginning at mean midnight on the Greenwich meridian and reckoned from 0 to 24 hours on a fixed basis. This reform promoted the use of 24 equal hours (each of 60 minutes, as per established conventions) divided into 60-minute segments worldwide, facilitating coordinated railway schedules, maritime navigation, and telegraphy, and laying the foundation for modern time zones.^[36]^[37] In the mid-20th century, the push for greater precision in timekeeping led to the atomic redefinition of the second, inherently stabilizing the minute as 60 such seconds. The 13th General Conference on Weights and Measures (CGPM), held in 1967, redefined the second as the duration of exactly 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 rest and at a temperature of 0 Kelvin. This shift from the ephemeris second—based on Earth's orbital motion around the Sun—to an atomic standard improved accuracy by orders of magnitude, enabling reliable synchronization in scientific instruments, computing, and global broadcasting. Further reforms addressed the divergence between atomic and astronomical time without compromising the minute's fixed length. Coordinated Universal Time (UTC) was formally introduced on January 1, 1972, by the International Radio Consultative Committee, building on the atomic second while incorporating occasional leap seconds to align with Earth's irregular rotation. These leap seconds, inserted at the end of a UTC month (typically June or December), make the total seconds in that day 86,401, while preserving the invariant 60-second minute, ensuring UTC remains within 0.9 seconds of Universal Time 1 (UT1). This system has maintained civil time's stability for telecommunications, aviation, and financial transactions since its inception.^[38]^[39] As of November 2025, ongoing discussions address the future of leap seconds. In 2022, the 27th CGPM adopted Resolution 4, deciding to discontinue leap seconds in UTC no later than 2035, allowing the timescale to gradually diverge from Earth's rotation without further adjustments. This aims to resolve implementation challenges in digital systems. Additionally, Earth's rotation has accelerated in recent years, potentially necessitating the first negative leap second (shortening a day to 86,399 seconds) around 2029, though effects from climate change, such as melting polar ice, may delay this. No leap second is scheduled for the end of December 2025.^[40]^[41] These developments culminated in broader international standards for time representation, enhancing the minute's interoperability. The ISO 8601 standard, first published in 1988 by the International Organization for Standardization, specifies a structured format for dates and times, including the basic time notation as HHMMSS (hours, minutes, seconds) or the extended HH:MM:SS, to ensure unambiguous data exchange across systems. By mandating consistent inclusion of minutes in temporal expressions—such as in the combined date-time format YYYY-MM-DDThh:mm:ss—this standard has been widely adopted in computing protocols, electronic data interchange, and international documentation, underscoring the minute's essential role in precise global timing.^[42]

Measurement and Usage

In Timekeeping Devices

In mechanical timekeeping devices, the minute is regulated by escapement mechanisms that control the release of stored energy from a weight or mainspring, driving the gear train to advance the minute hand at a consistent rate. The verge escapement, the earliest known mechanical escapement, emerged in Europe during the late 13th century and enabled the development of the first tower clocks in the early 14th century, which primarily indicated hours through striking bells but laid the foundation for finer time divisions. By the mid-14th century, these mechanisms had evolved to support dial faces in Italian public clocks, allowing for approximate hourly tracking that progressed toward minute precision as gear ratios were refined. The introduction of the minute hand itself occurred around 1577, when German clockmaker Jost Burgi added it to an astronomical clock for Tycho Brahe, enabling direct visual indication of minutes on analog dials through a dedicated gear connected to the escapement-regulated train.^[11]^[43] The transition to electronic timekeeping marked a significant advancement in minute accuracy with the invention of quartz movements in wristwatches and alarm devices. In 1969, Seiko introduced the Quartz Astron 35SQ, the world's first commercial quartz wristwatch, which utilized a quartz crystal oscillator vibrating at 8,192 Hz under electrical stimulation from a battery to generate precise time signals. This replaced mechanical oscillators with an electronic circuit that divided the high-frequency vibrations into one-second increments, driving a stepping motor to advance hands or trigger alarms with an accuracy of ±5 seconds per month—equivalent to about 1 minute per year—vastly improving reliability for minute-level tracking in portable devices. Quartz technology facilitated the integration of alarm functions set to exact minutes, as the stable oscillation minimized drift and enabled consistent wake-up or reminder triggers in both wristwatches and standalone clocks.^[44]^[45] Digital displays further streamlined minute presentation through LED and LCD formats adopting the HH:MM notation for intuitive readability. The Hamilton Pulsar P-1, released in 1972, was the first production digital wristwatch, featuring a push-button-activated LED display that illuminated hours and minutes in a rectangular red numeric format, marking the shift from analog hands to direct digital readout. By the mid-1970s, LCD technology supplanted early LED models due to lower power consumption and continuous visibility without user activation; watches like the 1976 Texas Instruments LED prototypes and subsequent LCD variants from Seiko and Casio standardized the 24-hour or 12-hour HH:MM layout, allowing users to instantly discern minutes without interpreting hand positions. This format became ubiquitous in electronic timepieces, supporting features like stopwatch timing and alarms calibrated to specific minutes.^[46]^[47] In computerized timekeeping systems, the Network Time Protocol (NTP) synchronizes device clocks to atomic standards, ensuring minute accuracy across distributed networks. Developed by David L. Mills in 1985, NTP operates via a stratum hierarchy of servers, with primary strata querying atomic clocks (such as cesium oscillators) for Coordinated Universal Time (UTC) references, then propagating adjustments to client devices through timestamped packet exchanges. This process compensates for network latency and clock drift, achieving typical synchronization offsets of 1–50 milliseconds on local networks—far exceeding minute-level precision—but guaranteeing that digital displays and logs align correctly to the exact minute for applications like scheduling and logging. NTP's robustness has made it essential for internet-connected computers, where even modest accuracy ensures reliable minute handoffs in virtual and physical timepieces.^[48]

In Everyday and Legal Contexts

In everyday life, the minute serves as a fundamental unit for scheduling activities, enabling precise coordination in calendars and transport systems. Digital calendars, such as those used in professional and personal planning, typically allow events to be set to the exact minute to facilitate meetings, appointments, and deadlines.^[49] Transport timetables worldwide rely on minute-level precision; for instance, PATH commuter rail schedules in the New York-New Jersey area list departure times to the minute, with trains potentially departing up to three minutes early or late to maintain efficiency during peak hours.^[50] This granularity ensures reliable connections and minimizes wait times for passengers in urban transit networks. In legal frameworks, the minute provides the precision required for enforceable obligations in contracts and regulations, particularly where timing directly impacts compliance. Clauses like "time is of the essence" in business agreements emphasize that performance must occur at or within specified times, often detailed to the hour and minute to avoid breaches, as seen in supply and delivery contracts.^[51] The EU Working Time Directive mandates recording of working hours to enforce limits on daily and weekly labor, with member states like Germany requiring logs down to the minute to verify rest periods and overtime.^[52]^[53] Cultural norms around the minute reflect varying attitudes toward punctuality and time management. In business contexts in Japan and Germany, arriving "on the minute" is a sign of respect and professionalism, with Japanese trains famously adhering to schedules within seconds, influencing corporate meetings to start precisely as planned.^[54] In contrast, some Latin American cultures, including Mexico, embrace "hora mexicana," a flexible perception of time where events may begin later than the scheduled minute, prioritizing relationships over strict adherence.^[55] This polychronic approach allows for overlapping activities without rigid enforcement of minute-based timing.^[56] Billing practices often charge based on minutes to reflect usage duration accurately. Telephony services, including pay-per-call lines regulated by the FTC, disclose costs per minute to ensure transparency in consumer billing.^[57] Similarly, municipal parking regulations meter fees incrementally; for example, New Rochelle, New York, charges $0.25 for every 12 minutes of on-street parking to manage urban space efficiently.^[58] These systems promote fair resource allocation while tying costs directly to time spent.

In Scientific and Technical Applications

In astronomy, the minute serves as a fundamental unit for tracking celestial objects relative to the fixed stars, where sidereal minutes are employed to account for Earth's rotation against the stellar background. A sidereal day, defined as the time for Earth to complete one rotation relative to distant stars, lasts approximately 23 hours, 56 minutes, and 4 seconds in solar time, making the sidereal minute slightly shorter than its solar counterpart by about 0.16 seconds. This distinction is crucial for precise observations, as astronomers use sidereal time to schedule telescope pointings, ensuring that stars and other celestial bodies return to the same position in the sky every sidereal day rather than every solar day, which is lengthened by Earth's orbital motion around the Sun.^[59]^[60] In physics, particularly in contexts involving high velocities or strong gravitational fields, the duration of a minute is influenced by relativistic effects, necessitating corrections to maintain accuracy in time-dependent systems. For instance, in the Global Positioning System (GPS), satellite clocks experience time dilation due to both special relativity (from their orbital speed of about 14,000 km/h) and general relativity (from weaker gravity at altitude), resulting in a net gain of approximately 38 microseconds per day compared to ground clocks; without pre-adjustments, this would accumulate to positional errors of kilometers within hours. These effects alter the perceived length of a minute on satellites by fractions of a microsecond, but onboard clock frequencies are preset to run slower by a factor of about 4.45 parts in 10^{10} to compensate for the relativistic effects, ensuring GPS signals remain accurate for navigation.^[61]^[62] In engineering applications such as vibration analysis, minute-scale intervals are utilized to monitor and diagnose machinery health by integrating vibration signals over short periods, allowing detection of subtle faults in rotating equipment like gears and turbines. For example, averaging vibrations at two-minute intervals in time-domain analysis reveals early indicators of wear or imbalance, enabling predictive maintenance before failures occur, as demonstrated in studies of gear fault progression where such sampling captures transient anomalies without overwhelming data volume. This approach balances resolution and computational efficiency, with minute-long integrations providing sufficient statistical reliability for trend analysis in industrial settings.^[63]^[64] Metrology standards for the minute emphasize traceability to atomic time scales, with organizations like the National Institute of Standards and Technology (NIST) providing calibration protocols to ensure devices measure intervals with high precision. NIST's Stopwatch and Timer Calibrations guideline requires instruments used for timing to achieve accuracy within 15 seconds over a 24-hour period, while for shorter intervals like 5 minutes, uncertainties should not exceed about 17 milliseconds to support reliable laboratory measurements. These standards involve comparisons against UTC(NIST) via GPS carrier-phase techniques, reported every 10 minutes, guaranteeing that minute-based calibrations in scientific instruments maintain uncertainties below 3.4 seconds for extended 24-hour tests.^[65]^[66]^[67]

Equivalents and Conversions

Relations to Other Time Units

The minute is defined as exactly 60 seconds in the International System of Units (SI), where the second is the base unit of time.^[68] Smaller subdivisions include the millisecond, equal to one-thousandth of a second or approximately 1/60,000 of a minute, and the microsecond, one-millionth of a second or about 1/60,000,000 of a minute; these fractions are formed using standard SI prefixes applied to the second. This hierarchical structure allows precise measurement of short intervals, such as in computing and physics experiments. In larger temporal scales, one minute constitutes 1/60 of an hour, which itself equals 3,600 seconds.^[68] A standard day, defined as 86,400 seconds, contains exactly 1,440 minutes (24 hours × 60 minutes).^[68] For annual scales, a non-leap year of 365 days totals 525,600 minutes (365 × 1,440), providing a baseline for long-term timekeeping in calendars and planning.^[69] Beyond SI conventions, the minute integrates into historical and specialized systems. In astronomical timekeeping, the Julian day—a continuous count of days since January 1, 4713 BCE—expresses time as an integer day plus a fractional part, where one full Julian day equates to 1,440 minutes, facilitating precise ephemeris calculations.^[70] Similarly, in military and NATO contexts, the 24-hour clock format denotes time as hours (00–23) followed by minutes (00–59), such as 1430 for 2:30 PM, ensuring unambiguous communication without AM/PM distinctions.^[71] Positioning the minute within broader temporal hierarchies reveals its intermediate scale: equivalent to 60 seconds or roughly 10¹ seconds on logarithmic orders of magnitude. This places it far above quantum limits, like the Planck time of 5.391247 × 10⁻⁴⁴ seconds—the smallest meaningful interval in theories combining gravity and quantum mechanics—and well below cosmic durations, such as the universe's age of approximately 13.82 billion years, or about 4.36 × 10¹⁷ seconds.^[72]^[73] Thus, the minute bridges human-scale events with the vast spectrum from subatomic fluctuations to the universe's evolution.

Angular Equivalents and Calculations

The arcminute (′), a subunit of angular measure, equals one-sixtieth of a degree (°).^[74] Consequently, a full circle of 360° contains 21,600 arcminutes, and each arcminute subdivides into 60 arcseconds (″).^[74] To convert arcminutes to radians, divide by 60 to obtain degrees, then multiply by π/180, yielding the exact proportion of 1 arcminute = π/10800 radians.^[75] This evaluates numerically to approximately 0.000290888 radians.^[76] In navigational calculations, 1 arcminute of latitude subtends a distance of approximately 1 nautical mile (1,852 meters) on Earth's surface, a convention originating from the arc length along a meridian or the equator.^[77] For instance, the formula for the linear distance d in nautical miles corresponding to an angular separation \theta in arcminutes at latitude \phi simplifies near the equator (\phi \approx 0) to d \approx \theta / 60 degrees converted to nautical miles, but adjustments via the cosine of latitude account for longitudinal variations: d \approx (\theta / 60) \times 60 \times \cos \phi nautical miles.^[78] Arcminutes enhance precision in geographic coordinate systems, such as latitude and longitude, where positions are denoted in degrees°, arcminutes′, and arcseconds″ (DMS format).^[79] For example, 1 arcminute of latitude equates to roughly 1,851 meters globally, enabling sub-kilometer accuracy in mapping and surveying applications.^[78]

Variations Across Systems

In the French Revolutionary calendar, introduced in 1793 and used until 1805, time was decimalized such that each day consisted of 10 hours, with each hour divided into 100 minutes and each minute into 100 seconds; this system, intended to align with metric reforms, was abandoned by 1806 due to practical resistance and lack of widespread adoption.^[6] Cultural time systems exhibit variations in minute usage tied to traditional practices. In Islamic tradition, the five daily prayers (salah) are scheduled based on the sun's position relative to the horizon, leading to prayer intervals that fluctuate in duration throughout the year—measured in standard minutes but varying from as little as 60 minutes for some periods in summer to over 300 minutes in winter at certain latitudes—while the lunar calendar governs the dates of observance without altering the solar-based time divisions.^[80] In traditional Chinese timekeeping, the day was divided into 12 shí (時), each approximately two modern hours, further subdivided into eight kè (刻) of about 15 minutes each, with smaller units like fractional kè equivalent to roughly 2.4 minutes; this structure, used historically alongside zodiac associations, resulted in uneven alignments with the 60-minute hour of contemporary systems.^[81] In aviation and other transport systems, Zulu time—equivalent to Coordinated Universal Time (UTC)—serves as the global standard for scheduling and navigation to avoid confusion across borders, while local times incorporate offsets that sometimes deviate by non-hour increments, such as India's UTC+5:30 or Nepal's UTC+5:45, requiring pilots to adjust flight logs accordingly for precise minute-level coordination.^[82] Historically obsolete distinctions include the mean solar minute, based on the average length of a solar day (86,400 seconds), versus the apparent solar minute, derived from the actual sun's position, which varies by up to 30 seconds per day due to Earth's elliptical orbit and axial tilt; this discrepancy, quantified by the equation of time reaching a maximum of about 16 minutes annually, necessitated adjustments in early astronomical timekeeping before modern standardization.^[83]

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International Conference Held at Washington for the Purpose of Fixing a Prime Meridian and a Universal Day. October, 1884. Protocols of the Proceedings.
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The international Meridian Conference, Washington, 1884
All countries would adopt a universal day. The universal day would be a Mean Solar Day, beginning at the Mean Midnight at Greenwich and counted on a 24 hour ...
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[PDF] The leap second: its history and possible future
Since 1972, when UTC was introduced, there have been twenty-two leap seconds, all of which have been positive. 3. Time measured by the rotation of the Earth.
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The leap second - National Research Council Canada
Jan 9, 2020 · Since 1972, the duration of the second for UTC has been fixed at the value established by an average of atomic clocks around the world ( ...
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[PDF] ISO 8601 : 1988 - NIST Technical Series Publications
May 1, 1991 · ISO 8601:1988 is an international standard for data elements and interchange formats, focusing on the representation of dates and times to ...
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History of Clocks - The Inventors
In 1577, Jost Burgi invented the minute hand. Burgi's invention was part of a clock made for Tycho Brahe, an astronomer who needed an accurate clock for his ...
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Milestones:Electronic Quartz Wristwatch, 1969
Dec 31, 2015 · This quartz watch is accurate to plus or minus five seconds a month, or one minute per year. Its quartz crystal oscillates at a rate of ...Missing: invention precise
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The birth of the quartz timepiece | THE SEIKO MUSEUM GINZA
On December 25, 1969, Seiko launched the world's first quartz wristwatch—the Seiko Quartz Astron 35SQ. The price was 450,000 yen, around the same price as some ...
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Four Revolutions: The Lost Chapter: A Concise History Of The LED ...
Feb 26, 2018 · Hamilton's Pulsar Time Computer was the world's first digital watch and the first star of the quartz watch revolution.
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[PDF] The “Quartz Crisis” and Swiss Watchmaking: Part 1
Mar 1, 2024 · In 1970, the first quartz watch with digital display was released: the Hamilton Pulsar (Figure 10), with LED display, developed in ...
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[PDF] Internet time synchronization: the network time protocol
For many applications, especially distributed internet applications, much greater accuracy and reliability is required. This paper presents an overview of the ...
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Google Calendar to Manage More than Time - Human Resources
Jan 8, 2024 · Use your calendar to help manage work and life, view multiple calendars, integrate with apps such as Zoom and Slack to save time, and more!Missing: sources | Show results with:sources
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Schedules and Maps - Port Authority of New York and New Jersey
Trains may leave up to three minutes earlier or later than times shown. 9 St. & 23 St. stations are closed daily from 11:59 PM – 5 AM for maintenance-related ...Missing: sources | Show results with:sources
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What does time is of the essence mean in a business contract?
Sep 27, 2024 · When 'time is of the essenceʼ in a contract, it means every deadline matters—miss one, and you're in breach. Itʼs a way to ensure all parties ...
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Recording Working Hours: requirements across the European Union
Mar 7, 2024 · The Working Time Directive 2003 requires Member States to take measures necessary to ensure that workers are entitled to their Directive ...<|separator|>
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https://www.panynj.gov/path/en/schedules-maps.html
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5 Countries Known for Always Being Punctual - Daily Passport
Jul 8, 2025 · In certain countries, punctuality is a way of life. Locals always arrive five minutes ahead of time, trains adhere to a strict schedule, and businesses open ...
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[PDF] Geography of Time - Rhuthmos
learn to translate hora ingles into time frames like hora mexicano, hora brasileiro, Indian Time, CPT, and rubber time. You can be pre- pared beforehand for ...
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[PDF] Intercultural-Communication-Dynamics.pdf
after the stated time, leading to such colloquialisms as. “hora brasilera” or “hora mexicana.” • In Germany, meetings start on time, follow a defined agenda ...
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Complying with the 900 Number Rule | Federal Trade Commission
If the call is billed on a time-sensitive basis, the ad must state the cost per minute and any minimum charge. The ad also must state the maximum charge, if the ...
[55]
Metered Parking | New Rochelle, NY
On-Street parking meters throughout the City have a maximum time limit of 2 hours with a rate of $0.25 for each 12 minutes.
[56]
Solar Time vs. Sidereal Time - Las Cumbres Observatory
Sidereal time is based on when the vernal equinox passes the upper meridian. This takes approximately 4 minutes less than a solar day.
[57]
Time Scales - Introduction to Astronomy
The sidereal day is 23 hours and 56 minutes long. Solar day: This is the length of time it takes for the Earth to come around to the same position relative ...
[58]
Real-World Relativity: The GPS Navigation System
Mar 11, 2017 · A calculation using General Relativity predicts that the clocks in each GPS satellite should get ahead of ground-based clocks by 45 microseconds per day.
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Relativity in the Global Positioning System - PMC - NIH
For a low earth orbiter such as the Space Shuttle, the velocity is so great that slowing due to time dilation is the dominant effect, while for a GPS satellite ...
[60]
Investigation of Effectiveness of Some Vibration‐Based Techniques ...
The averaged gear vibrations monitored at two-minute intervals are used in the time domain analysis and it was found that early fault indications are revealed ...
[61]
Condition Evaluation of Steam Turbine Generator Using Minute ...
This work attempts to retrieve fault indications from the minute-interval integrated signal sample via its trend and periodicity components to predict ...
[62]
[PDF] Stopwatch and Timer Calibrations - Time and Frequency Division
NIST Handbook 44 [7] specifies that instruments that are required to calibrate timing devices must be accurate to within 15 s per 24 h period ( ...
[63]
[PDF] SOP 24 Calibration of Stopwatches and Timing Devices
The uncertainty must be less than 3.4 seconds for a 24-hour interval and a 1 s resolution device may be able to meet this requirement.
[64]
Time Measurement and Analysis Service (TMAS) | NIST
TMAS monitors local time standards by comparing them to UTC(NIST) using GPS, reporting results via the internet every 10 minutes.
[65]
https://tf.nist.gov/general/pdf/1930.pdf
[66]
Calendar Calculations
It is equal to 365 days, 5 hours, 48 minutes, and 46 seconds, or 365.2422 days. The tropical year is used to keep track of seasons, planting, and harvesting.
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Julian Date Converter - Astronomical Applications Department
Julian dates (abbreviated JD) are simply a continuous count of days and fractions since noon Universal Time on January 1, 4713 BC (on the Julian calendar).
[68]
24-hour clock | Definition, History, Uses, & Facts - Britannica
The 24-hour clock is the international standard format for time (ISO 8601) and is currently the most widespread time notation worldwide.12-Hour Clock · 3:00 Pm · 24-Hour Clock
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Planck time - CODATA Value
Planck time $t_{\rm P}$ ; Numerical value, 5.391 247 x 10-44 s ; Standard uncertainty, 0.000 060 x 10-44 s.
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Planck reveals an almost perfect Universe - ESA
The data imply that the age of the Universe is 13.82 billion years. “With the most accurate and detailed maps of the microwave sky ever made, Planck is ...
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[PDF] Volume 99 - NIST Technical Series Publications
There are 360 degrees (°) in a circle, 60 arcmin- utes (') in a degree, and 60 arcseconds (") in an arcminute. Therefore, there are 3600 arcseconds in a ...<|separator|>
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[PDF] Transit of Venus M ath - Space Math @ NASA
Jun 8, 2004 · 1 degree = 60 arcminutes. 1 arcminute = 60 arcseconds. We also use radian units where. 1 radian = 57.295833 degrees. Problem 1 – How many ...
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Arcminute | COSMOS - Centre for Astrophysics and Supercomputing
An arcminute (denoted by the symbol '), is an angular measurement equal to 1/60 of a degree or 60 arcseconds. There are 3,437.75' in a radian, so that 1' = 2. ...
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Basics of Spaceflight: Glossary - NASA Science
Jan 31, 2025 · nm -- Nautical Mile, equal to the distance spanned by one minute of arc in latitude, 1.852 km. NMC -- Network Monitor and Control subsystem ...
[75]
USGS OFR 2011-1127: Construction of a 3-Arcsecond Digital ...
One arc-second (1/3,600 of 1 degree (°)) is 1/60th of 1 minute of arc, where a 1 minute of arc is equal to 1/60th of 1°. * The approximate meters at the equator ...
[76]
How much distance does a degree, minute, and second cover on ...
One degree of latitude equals approximately 364,000 feet (69 miles), one minute equals 6,068 feet (1.15 miles), and one-second equals 101 feet. One-degree of ...Missing: geometry | Show results with:geometry
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Decimal time - MacTutor History of Mathematics
On 1 November 1795 (11 brumaire by the new calendar) a law was passed which required the creation of clocks with ten hours in the day, 100 minutes in an hour, ...
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Understanding Muslim Prayer Times - A Guide for Muslims
In general, a person can make an accurate calculation of the time of prayer only when he/she knows the declination of the Sun on the date of the computation.Missing: variations | Show results with:variations
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Traditional Chinese Timekeeping | Encyclopedia MDPI
Oct 30, 2022 · Each shí (時; 时) was 1⁄12 of the time between one midnight and the next, making it roughly double the modern hour. These dual hours are named ...
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Half Hour and 45-Minute Time Zones - Time and Date
Some time zones have 30 or 45-minute offsets from UTC, unlike the usual one-hour intervals. Examples include India (UTC +5:30) and some Australian states.
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The Equation of Time - Astronomical Applications Department
the difference apparent solar time minus mean solar time — in minutes as a function of date (click on it for ...