Table of Contents
94 relations: Acceleration, Al-Biruni, Ampere, Atomic clock, Attosecond, Becquerel, British Science Association, Caesium, Caesium standard, Candela, Carl Friedrich Gauss, Centimetre–gram–second system of units, Christiaan Huygens, Chronometry, Civil time, Clock, Coordinated Universal Time, Day, Ephemeris time, Epoch (astronomy), Escapement, Femtosecond, Fourth, fifth, and sixth derivatives of position, Frequency, Full moon, General Conference on Weights and Measures, Gravitational time dilation, Gregorian calendar, Ground state, Hertz, Hour, Hyperfine structure, International Astronomical Union, International Atomic Time, International Bureau of Weights and Measures, International System of Units, Inverse second, Isotopes of caesium, ΔT (timekeeping), Jerk (physics), John Harrison, Jost Bürgi, Julian year (astronomy), Kelvin, Kilogram, Lamb shift, Leap second, Leap year, List of non-standard dates, Metre, ... Expand index (44 more) »
- Centimetre–gram–second system of units
- Orders of magnitude (time)
- SI base units
Acceleration
In mechanics, acceleration is the rate of change of the velocity of an object with respect to time.
Al-Biruni
Abu Rayhan Muhammad ibn Ahmad al-Biruni (ابوریحان بیرونی; أبو الريحان البيروني; 973after 1050), known as al-Biruni, was a Khwarazmian Iranian scholar and polymath during the Islamic Golden Age.
Ampere
The ampere (symbol: A), often shortened to amp,SI supports only the use of symbols and deprecates the use of abbreviations for units. Second and ampere are sI base units.
Atomic clock
An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms.
Attosecond
An attosecond (abbreviated as as) is a unit of time in the International System of Units (SI) equal to 10−18 or 1⁄1 000 000 000 000 000 000 (one quintillion) of a second. Second and attosecond are orders of magnitude (time).
Becquerel
The becquerel (symbol: Bq) is the unit of radioactivity in the International System of Units (SI).
British Science Association
The British Science Association (BSA) is a charity and learned society founded in 1831 to aid in the promotion and development of science.
See Second and British Science Association
Caesium
Caesium (IUPAC spelling; cesium in American English) is a chemical element; it has symbol Cs and atomic number 55.
Caesium standard
The caesium standard is a primary frequency standard in which the photon absorption by transitions between the two hyperfine ground states of caesium-133 atoms is used to control the output frequency.
See Second and Caesium standard
Candela
The candela (or; symbol: cd) is the unit of luminous intensity in the International System of Units (SI). Second and candela are sI base units.
Carl Friedrich Gauss
Johann Carl Friedrich Gauss (Gauß; Carolus Fridericus Gauss; 30 April 177723 February 1855) was a German mathematician, astronomer, geodesist, and physicist who contributed to many fields in mathematics and science.
See Second and Carl Friedrich Gauss
Centimetre–gram–second system of units
The centimetre–gram–second system of units (CGS or cgs) is a variant of the metric system based on the centimetre as the unit of length, the gram as the unit of mass, and the second as the unit of time.
See Second and Centimetre–gram–second system of units
Christiaan Huygens
Christiaan Huygens, Lord of Zeelhem, (also spelled Huyghens; Hugenius; 14 April 1629 – 8 July 1695) was a Dutch mathematician, physicist, engineer, astronomer, and inventor who is regarded as a key figure in the Scientific Revolution.
See Second and Christiaan Huygens
Chronometry
Chronometry or horology is the science studying the measurement of time and timekeeping. Chronometry enables the establishment of standard measurements of time, which have applications in a broad range of social and scientific areas. Horology usually refers specifically to the study of mechanical timekeeping devices, while chronometry is broader in scope, also including biological behaviours with respect to time (biochronometry), as well as the dating of geological material (geochronometry).
Civil time
In modern usage, civil time refers to statutory time as designated by civilian authorities.
Clock
A clock or chronometer is a device that measures and displays time.
See Second and Clock
Coordinated Universal Time
Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time.
See Second and Coordinated Universal Time
Day
A day is the time period of a full rotation of the Earth with respect to the Sun. Second and day are orders of magnitude (time) and units of time.
See Second and Day
Ephemeris time
The term ephemeris time (often abbreviated ET) can in principle refer to time in association with any ephemeris (itinerary of the trajectory of an astronomical object).
Epoch (astronomy)
In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity.
See Second and Epoch (astronomy)
Escapement
An escapement is a mechanical linkage in mechanical watches and clocks that gives impulses to the timekeeping element and periodically releases the gear train to move forward, advancing the clock's hands.
Femtosecond
A femtosecond is a unit of time in the International System of Units (SI) equal to 10 or of a second; that is, one quadrillionth, or one millionth of one billionth, of a second. Second and femtosecond are orders of magnitude (time).
Fourth, fifth, and sixth derivatives of position
In physics, the fourth, fifth and sixth derivatives of position are defined as derivatives of the position vector with respect to time – with the first, second, and third derivatives being velocity, acceleration, and jerk, respectively.
See Second and Fourth, fifth, and sixth derivatives of position
Frequency
Frequency (symbol f), most often measured in hertz (symbol: Hz), is the number of occurrences of a repeating event per unit of time.
Full moon
The full moon is the lunar phase when the Moon appears fully illuminated from Earth's perspective.
General Conference on Weights and Measures
The General Conference on Weights and Measures (abbreviated CGPM from the Conférence générale des poids et mesures) is the supreme authority of the International Bureau of Weights and Measures (BIPM), the intergovernmental organization established in 1875 under the terms of the Metre Convention through which member states act together on matters related to measurement science and measurement standards.
See Second and General Conference on Weights and Measures
Gravitational time dilation
Gravitational time dilation is a form of time dilation, an actual difference of elapsed time between two events, as measured by observers situated at varying distances from a gravitating mass.
See Second and Gravitational time dilation
Gregorian calendar
The Gregorian calendar is the calendar used in most parts of the world.
See Second and Gregorian calendar
Ground state
The ground state of a quantum-mechanical system is its stationary state of lowest energy; the energy of the ground state is known as the zero-point energy of the system.
Hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second.
See Second and Hertz
Hour
An hour (symbol: h; also abbreviated hr) is a unit of time historically reckoned as of a day and defined contemporarily as exactly 3,600 seconds (SI). Second and hour are orders of magnitude (time) and units of time.
See Second and Hour
Hyperfine structure
In atomic physics, hyperfine structure is defined by small shifts in otherwise degenerate electronic energy levels and the resulting splittings in those electronic energy levels of atoms, molecules, and ions, due to electromagnetic multipole interaction between the nucleus and electron clouds.
See Second and Hyperfine structure
International Astronomical Union
The International Astronomical Union (IAU; Union astronomique internationale, UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and development through global cooperation.
See Second and International Astronomical Union
International Atomic Time
International Atomic Time (abbreviated TAI, from its French name temps atomique international) is a high-precision atomic coordinate time standard based on the notional passage of proper time on Earth's geoid.
See Second and International Atomic Time
International Bureau of Weights and Measures
The International Bureau of Weights and Measures (Bureau international des poids et mesures, BIPM) is an intergovernmental organisation, through which its 59 member-states act on measurement standards in areas including chemistry, ionising radiation, physical metrology, as well as the International System of Units (SI) and Coordinated Universal Time (UTC).
See Second and International Bureau of Weights and Measures
International System of Units
The International System of Units, internationally known by the abbreviation SI (from French Système international d'unités), is the modern form of the metric system and the world's most widely used system of measurement.
See Second and International System of Units
Inverse second
The inverse second or reciprocal second (s−1), also called per second, is a unit defined as the multiplicative inverse of the second (a unit of time).
Isotopes of caesium
Caesium (55Cs) has 41 known isotopes, the atomic masses of these isotopes range from 112 to 152.
See Second and Isotopes of caesium
ΔT (timekeeping)
In precise timekeeping, ΔT (Delta T, delta-T, deltaT, or DT) is a measure of the cumulative effect of the departure of the Earth's rotation period from the fixed-length day of International Atomic Time (86,400 seconds).
See Second and ΔT (timekeeping)
Jerk (physics)
Jerk (also known as jolt) is the rate of change of an object's acceleration over time.
John Harrison
John Harrison (– 24 March 1776) was an English carpenter and clockmaker who invented the marine chronometer, a long-sought-after device for solving the problem of calculating longitude while at sea.
Jost Bürgi
Jost Bürgi (also Joost, Jobst; Latinized surname Burgius or Byrgius; 28 February 1552 – 31 January 1632), active primarily at the courts in Kassel and Prague, was a Swiss clockmaker, mathematician, and writer.
Julian year (astronomy)
In astronomy, a Julian year (symbol: a or aj) is a unit of measurement of time defined as exactly 365.25 days of SI seconds each.
See Second and Julian year (astronomy)
Kelvin
The kelvin, symbol K, is the base unit of measurement for temperature in the International System of Units (SI). Second and kelvin are sI base units.
Kilogram
The kilogram (also kilogramme) is the base unit of mass in the International System of Units (SI), having the unit symbol kg. Second and kilogram are sI base units.
Lamb shift
In physics, the Lamb shift, named after Willis Lamb, is an anomalous difference in energy between two electron orbitals in a hydrogen atom.
Leap second
A leap second is a one-second adjustment that is occasionally applied to Coordinated Universal Time (UTC), to accommodate the difference between precise time (International Atomic Time (TAI), as measured by atomic clocks) and imprecise observed solar time (UT1), which varies due to irregularities and long-term slowdown in the Earth's rotation.
Leap year
A leap year (also known as an intercalary year or bissextile year) is a calendar year that contains an additional day (or, in the case of a lunisolar calendar, a month) compared to a common year. Second and leap year are units of time.
List of non-standard dates
Several non-standard dates are used in calendars for various purposes: some are expressly fictional, some are intended to produce a rhetorical effect (such as sarcasm), and others attempt to address a particular mathematical, scientific or accounting requirement or discrepancy within the calendar system.
See Second and List of non-standard dates
Metre
The metre (or meter in US spelling; symbol: m) is the base unit of length in the International System of Units (SI). Second and metre are sI base units.
See Second and Metre
Metric prefix
A metric prefix is a unit prefix that precedes a basic unit of measure to indicate a multiple or submultiple of the unit.
Microsecond
A microsecond is a unit of time in the International System of Units (SI) equal to one millionth (0.000001 or 10−6 or) of a second. Second and microsecond are orders of magnitude (time).
Millisecond
A millisecond (from milli- and second; symbol: ms) is a unit of time in the International System of Units equal to one thousandth (0.001 or 10−3 or 1/1000) of a second or 1000 microseconds. Second and millisecond are orders of magnitude (time).
Minute
Minute is a unit of time defined as equal to 60 seconds. Second and Minute are orders of magnitude (time) and units of time.
MKS units
The metre, kilogram, second system of units, also known more briefly as MKS units or the MKS system, is a physical system of measurement based on the metre, kilogram, and second (MKS) as base units.
Mole (unit)
The mole (symbol mol) is a unit of measurement, the base unit in the International System of Units (SI) for amount of substance, a quantity proportional to the number of elementary entities of a substance. Second and mole (unit) are sI base units.
Nanosecond
A nanosecond (ns) is a unit of time in the International System of Units (SI) equal to one billionth of a second, that is, of a second, or 10 seconds. Second and nanosecond are orders of magnitude (time).
New moon
In astronomy, the new moon is the first lunar phase, when the Moon and Sun have the same ecliptic longitude.
Newcomb's Tables of the Sun
Newcomb's Tables of the Sun (full title Tables of the Motion of the Earth on its Axis and Around the Sun) is a work by the American astronomer and mathematician Simon Newcomb, published in volume VI of the serial publication Astronomical Papers Prepared for the Use of the American Ephemeris and Nautical Almanac.
See Second and Newcomb's Tables of the Sun
Non-SI units mentioned in the SI
While the International System of Units (SI) is used throughout the world in all fields, many non-SI units continue to be used in the scientific, technical, and commercial literature.
See Second and Non-SI units mentioned in the SI
Optical fiber
An optical fiber, or optical fibre, is a flexible glass or plastic fiber that can transmit light from one end to the other.
Optical lattice
An optical lattice is formed by the interference of counter-propagating laser beams, creating a spatially periodic polarization pattern.
See Second and Optical lattice
Orbit
In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a planet, moon, asteroid, or Lagrange point.
See Second and Orbit
Orders of magnitude (time)
An order of magnitude of time is usually a decimal prefix or decimal order-of-magnitude quantity together with a base unit of time, like a microsecond or a million years. Second and orders of magnitude (time) are units of time.
See Second and Orders of magnitude (time)
Orpheus
In Greek mythology, Orpheus (Ancient Greek: Ὀρφεύς, classical pronunciation) was a Thracian bard, legendary musician and prophet.
Persians
The Persians--> are an Iranian ethnic group who comprise over half of the population of Iran.
Picosecond
A picosecond (abbreviated as ps) is a unit of time in the International System of Units (SI) equal to 10−12 or (one trillionth) of a second. Second and picosecond are orders of magnitude (time).
Q factor
In physics and engineering, the quality factor or Q factor is a dimensionless parameter that describes how underdamped an oscillator or resonator is.
Radian
The radian, denoted by the symbol rad, is the unit of angle in the International System of Units (SI) and is the standard unit of angular measure used in many areas of mathematics.
Revolution in Time
Revolution in Time: Clocks and the Making of the Modern World, is an influential history book by David S. Landes.
See Second and Revolution in Time
Roger Bacon
Roger Bacon (Rogerus or Rogerius Baconus, Baconis, also Rogerus), also known by the scholastic accolade Doctor Mirabilis, was a medieval English philosopher and Franciscan friar who placed considerable emphasis on the study of nature through empiricism.
Rydberg constant
In spectroscopy, the Rydberg constant, symbol R_\infty for heavy atoms or R_\text for hydrogen, named after the Swedish physicist Johannes Rydberg, is a physical constant relating to the electromagnetic spectra of an atom.
See Second and Rydberg constant
Seconds pendulum
A seconds pendulum is a pendulum whose period is precisely two seconds; one second for a swing in one direction and one second for the return swing, a frequency of 0.5 Hz. Second and seconds pendulum are units of time.
See Second and Seconds pendulum
Sexagesimal
Sexagesimal, also known as base 60, is a numeral system with sixty as its base.
Shutter speed
In photography, shutter speed or exposure time is the length of time that the film or digital sensor inside the camera is exposed to light (that is, when the camera's shutter is open) when taking a photograph.
SI base unit
The SI base units are the standard units of measurement defined by the International System of Units (SI) for the seven base quantities of what is now known as the International System of Quantities: they are notably a basic set from which all other SI units can be derived. Second and sI base unit are sI base units.
Sidereal year
A sidereal year, also called a sidereal orbital period, is the time that Earth or another planetary body takes to orbit the Sun once with respect to the fixed stars.
Speed
In kinematics, the speed (commonly referred to as v) of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit of time; it is thus a scalar quantity.
See Second and Speed
Speed of light
The speed of light in vacuum, commonly denoted, is a universal physical constant that is exactly equal to). According to the special theory of relativity, is the upper limit for the speed at which conventional matter or energy (and thus any signal carrying information) can travel through space.
Steradian
The steradian (symbol: sr) or square radian is the unit of solid angle in the International System of Units (SI).
Strontium
Strontium is a chemical element; it has symbol Sr and atomic number 38.
Sundial
A sundial is a horological device that tells the time of day (referred to as civil time in modern usage) when direct sunlight shines by the apparent position of the Sun in the sky.
System of units of measurement
A system of units of measurement, also known as a system of units or system of measurement, is a collection of units of measurement and rules relating them to each other.
See Second and System of units of measurement
Taqi ad-Din Muhammad ibn Ma'ruf
Taqi ad-Din Muhammad ibn Ma'ruf ash-Shami al-Asadi (تقي الدين محمد بن معروف الشامي; تقي الدين محمد بن معروف الشامي السعدي; Takiyüddin‎ 1526–1585) was an Ottoman polymath active in Cairo and Istanbul.
See Second and Taqi ad-Din Muhammad ibn Ma'ruf
Time
Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, and into the future.
See Second and Time
Time in physics
In physics, time is defined by its measurement: time is what a clock reads.
See Second and Time in physics
Time standard
A time standard is a specification for measuring time: either the rate at which time passes or points in time or both.
Tropical year
A tropical year or solar year (or tropical period) is the time that the Sun takes to return to the same position in the sky – as viewed from the Earth or another celestial body of the Solar System – thus completing a full cycle of astronomical seasons. Second and tropical year are units of time.
Tycho Brahe
Tycho Brahe (born Tyge Ottesen Brahe,; 14 December 154624 October 1601), generally called Tycho for short, was a Danish astronomer of the Renaissance, known for his comprehensive and unprecedentedly accurate astronomical observations.
United States Naval Observatory
The United States Naval Observatory (USNO) is a scientific and military facility that produces geopositioning, navigation and timekeeping data for the United States Navy and the United States Department of Defense.
See Second and United States Naval Observatory
Universal Time
Universal Time (UT or UT1) is a time standard based on Earth's rotation.
University of Pennsylvania Press
The University of Pennsylvania Press, also known as Penn Press, is a university press affiliated with the University of Pennsylvania, an Ivy League university in Philadelphia, Pennsylvania.
See Second and University of Pennsylvania Press
Watch
A watch is a portable timepiece intended to be carried or worn by a person.
See Second and Watch
William IV, Landgrave of Hesse-Kassel
William IV of Hesse-Kassel (24 June 153225 August 1592), also called William the Wise, was the first Landgrave of the Landgraviate of Hesse-Kassel (or Hesse-Cassel).
See Second and William IV, Landgrave of Hesse-Kassel
See also
Centimetre–gram–second system of units
- Abampere
- Abcoulomb
- Abhenry
- Abohm
- Abvolt
- Apostilb
- Barye
- Bril (unit)
- Centimetre
- Centimetre–gram–second system of units
- Cubic centimetre
- Debye
- Dyne
- Erg
- Gal (unit)
- Gauss (unit)
- Gaussian units
- Gilbert (unit)
- Gram
- Gram per cubic centimetre
- Maxwell (unit)
- Oersted
- Phot
- Poise (unit)
- Second
- Skot (unit)
- Statampere
- Statcoulomb
- Statmho
- Statohm
- Statvolt
- Stilb (unit)
Orders of magnitude (time)
- Attosecond
- Day
- Detailed logarithmic timeline
- Femtosecond
- Hour
- Logarithmic timeline
- Microsecond
- Millisecond
- Minute
- Month
- Nanosecond
- Orders of magnitude (time)
- Picosecond
- Second
SI base units
- Alternative approaches to redefining the kilogram
- Ampere
- Candela
- Kelvin
- Kilogram
- Metre
- Mole (unit)
- SI base unit
- Second
References
Also known as 1 E0 s, 1 E6 s, 1 E7 s, 1 E8 s, 1 second, 1e6 s, 1e7 s, 1e8 s, 9192631770, 9192631770 cycles of a Caesium atomic clock, Calendar Second, Gigasecond, Megasecond, Number of seconds in a year, Quettasecond, Ronnasecond, S (unit), SI second, Second (SI unit), Second (time), Second duration, Second of time, Seconds, Secound, Secs, Square seconds, Third (time).