Universal Time Definition

Universal Time or Coordinated Universal Time?
So which is the correct terminology when using a worldwide reference for time: UT or UTC? As my mother-in-law is fond of saying, 'It's six of one and half a dozen of the other.' In other words, it hardly matters, although - for the record - the U.S.

1: including or covering all or a whole collectively or distributively without limit or exception especially: available equitably to all members of a society universal health coverage. Universal Coordinated Time synonyms, Universal Coordinated Time pronunciation, Universal Coordinated Time translation, English dictionary definition of Universal Coordinated Time. UT The time at the Prime Meridian, calculated from the apparent rotation of the celestial sphere and used primarily by astronomers. Universal Time One degree of longitude is 4 minutes and Time is calculated based on longitude. The calculations of Sunrise and Ascendant are based on latitude and these mathematical values vary from latitude to latitude. Universal time - Greenwich Mean Time. Upachaya - The 3rd, 6th, 10th, and 11th houses in a natal chart.

Universal time definition science

Coordinated Universal Time (UTC) differs from international atomic time by an integral number of seconds and is the basis of most radio time systems and legal time systems. The step adjustments (leap seconds) are usually inserted after the 60th second of the last minute of December 31 or June 30.

Questions Show: Telescope Suggestions, Black Hole Energy, and Universal Time
Celestron telescope.
What starting telescope equipment does the Astronomy Cast team suggest? How much energy does a black hole generate? And how do we measure time outside the Earth?

~ Eventually, as the nations grew, and as telegraphs and railroads quickened communications, people considered the concept of a universal standard for time that was independent of location. The result was the establishing of Greenwich Mean Time in 1880.

~ conversion
NASAJPL late news
Cornell University late news
How popular are the Mars rovers? ..

~ is a timescale based on the rotation of the Earth. It is a modern continuation of Greenwich Mean Time , i.e., the mean solar time on the meridian of Royal Observatory, Greenwich, and GMT is sometimes used loosely as a synonym for UTC..

~
When it is noon where you live, it is midnight on the opposite side of the world. Usually when we think of time, we mean 'the time of day where I live'. If we say something happened at 9 AM, we mean it..more
Radio Waves ..

~ (UT)
(a) The local mean time of the prime meridian. It is the same as Greenwich mean time, counted from 0 hours beginning at Greenwich mean midnight.

~ (UT). Standard time (and its daylight-saving variant) serves fine within a given time zone. But when a time applies worldwide, such as in an astronomical almanac, which time zone should be favored?

~ (UT)
Time system that forms the basis for our civil time.
My web site: Ole's Astronomy Site ..

~ (UT1) - A time scale based on the rotation of Earth in relation to distant celestial objects (stars and quasars); UT1 is a non-uniform time scale because Earth's rotational period is slowly increasing due to tidal interaction with the Moon; the modern continuation of Greenwich Mean Time (GMT), i.e.

~ (UT). See Coordinated ~.
Very High Frequency (VHF). That portion of the radio frequency spectrum from 30 to 300 MHz.
Very Low Frequency (VLF). That portion of the radio frequency spectrum from 3 to 30 kHz.

~
In simplest terms, the time at the longitude of Greenwich, England. ~ (UT) is widely used in international publications as a standard time.

~ (UT, or UTC). A measure of time used by astronomers; UT conforms (within a close approximation) to the mean daily (apparent) motion of the sun. UT is determined from observations of the diurnal (daily) motions of the stars for an observer on the earth.

~ (UT)
Also known as Greenwich Mean Time, this is local time on the Greenwich meridian. ~ is used by astronomers as a standard measure of time.
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~ (UT): The ~ (UT) is the same as Greenwich Mean Time (GMT), which is the local time in the time zone of Greenwich, England.
V
Vernal Equinox: The vernal equinox is the equinox which occurs on the 21st of March.

~ (UT, UTC). Co-ordinated ~. The time standard by which Greenwich Mean Time became known as for scientific purposes in 1928. UTC is the time given by broadcast time since 1972. The time-scale is widely known as Greenwich Mean Time but astronomically speaking the term GMT is no longer used.

~ - Also recognized as Greenwich Mean Time, forming the basis in all civil time keeping. Local time centered in Greenwich, England.
Universe - All that exists
UT - short for ~ ..

~ (UT)
Time based upon the Earth's rotation and the basis for civil time keeping. It is essentially the same as Greenwich Mean Time.
UNIVERSE ..


~
~ (abbreviated UT) is the same as Greenwich Mean Time (abbreviated GMT); it is the time zone of Greenwich, England (longitude zero).
Planet Distance from U.A.
(Astronomical Units) Orbital period
Planetary Year Mass
#1 ..

~ Coordinated [LLM96]
Universe
The total celestial cosmos. According to Gott et al. the universe seems to be on a large scale isotropic, homogeneous, matter-dominated, and with negligible pressure.

UT (~) The local time at the 0 meridian passing through Greenwich, England; it is t he same everywhere. Same as GMT (Greenwich Mean Time).
V
Vacuum A space absent of matter or nearly so.

UT ~ The time system usually used for timing astronomical events is ~, also known as UT, or ~ Coordinated, or UTC. This is essentially the civil time used at Greenwich; corrected for time zones, it is used throughout the world.

~ (UT) A time system measured from the meridian of Greenwich in England ..

~ Coordinated
Similar to Greenwich Mean Time , this is local time on the Greenwich meridian. GMT is based on the observation of the Sun, UTC is based on atomic clocks. Always within 0.9s of each other.
Uranus ..

~ (UT) Non-uniform TIMESCALE based on the rate of rotation of the Earth. In the past this was determined by making accurate observations of star positions using an instrument known as a PHOTOGRAPHIC ZENITH TUBE (PZT), but today it utilizes a technique called satellitelaser ranging.

~ (UT): a measure of time that conforms, within a close approximation, to the mean diurnal motion of the Sun and serves as the basis of all civil timekeeping. UT is formally defined by a mathematical formula as a function of sidereal time.

Definition

~ (UT):
a generic reference to one of several time scales that approximate the mean diurnal motion of the Sun; loosely, mean solar time on the Greenwich meridian (previously referred to as Greenwich Mean Time).

A truly ~ is a doomed endeavour, especially if we start travelling at relativistic speeds. I know, this is not happening anytime soon. But the point is, relativity has rendered obsolete the concept of simultaneity.

Coordinated ~: Coordinated ~ (UTC) is a system we astronomers use. Also, times for us are usually converted to 24-hour time, i.e., 1 a.m. is 0100 hours, 1 p.m. is 1300 hours and so on. Mid-night or 12 a.m. is 0000 hours, not 2400.

Main article: ~
The equation of time-above the axis a sundial will appear fast relative to a clock showing local mean time, and below the axis a sundial will appear slow.

~ (abbr UT) Time defined by the rotational motion of the earth and determined from the apparent diurnal motions which reflect this rotation; because of variations in the rate of rotation, ~ is not rigorously uniform. Also called Greenwich mean time. Compare ephemeris time.

~ Abbreviated UT. The same as Greenwich Mean Time (GMT) in England. US Eastern Standard Time (EST) is five hours earlier than ~. Universe The totality of all space and time; all that is, has been, and will be.

Whatever time it is in Greenwich is called ~ (abbreviated UT).
Well, that's almost true. Like folks in many other parts of the world, during the autumn the people of Greenwich set their clocks back an hour for the dark wintermonths and then set it forward an hour in the spring.

For historical reasons, this 'world' time was chosen to be the mean solar time at Greenwich, England (0 degrees longitude), and this time is called the ~ (UT).

umbra the total part of a shadow ~ (UT) local time on the Greenwich meridian
V
variable star a star whose apparent brightness changes over time; this change may regular or irregular ..

~ (UT) is a world-wide measure of time, the same everywhere; a common scheme is based on the time at the meridian of zero longitude in Greenwich, at the edge of London, England (it is also called Greenwich Mean Time or GMT; astronomers may define UT differently).

Why They Call It ~
Astronomical, civil, and defense interests overlap in their need for precise coordinate systems and timekeeping. Nonastrophysical uses include navigation, clock synchronization, ballistic missile guidance, and secure communications.

Coordinated ~ (UTC). By international agreement, the local time at the prime meridian, which passes through Greenwich, England. It was formerly known as Greenwich Mean Time, or sometimes simply ~. There are 24 time zones around the world, labeled alphabetically.

The JD is always half a day off from ~, because the current definition of JD was introduced when the astronomical day was defined to start at noon (prior to 1925) instead of midnight. Thus, 1995 Oct. 10.0 UT = JD 2450000.5.
km kilometer = 0.6 mile.

TERRESTRIAL DYNAMICAL TIME (TDT OR TT): Time scale used in orbital computations; TDT is tied to atomic clocks (International Atomic Time, TAI), whereas ~ is tied to observations. Prior to 1992, Ephemeris Time (ET) was used in publications of the ICQ/CBAT/MPC; since then, TT has been used.

I'm sorry, but ~ (UT) zone is the time in Western Europe and is thus totally misleading for those who might want to see the eclipse in real life. Had Mr. Betts used LOCAL time (Pacific Daylight, (PDT)), it might be useful.

from Jupiter at 9:00 ~, making it the closest conjunction of any two naked eye planets for the entire 2015.
2/07: With some luck, Comet C/2013 US10 Catalina may become visible with binoculars.
6/07: Earth reaches aphelion at 13:00 ~.

Task

This calendar was used in conjunction with the Coordinated ~ standard (UTC) to give a single value for timekeeping all over the planet. UTC was adopted throughout the Solar System at first, but once permanent colonies were established on the Moon and Mars new calendars were established for those worlds.

Pacific Daylight Time (11:30 ~), the upper stage of a Centaur rocket will purposefully crash into the crater Cabeus near the south pole of the moon. Four minutes later, a second probe will fly through the dredged-up lunar debris and analyze the material for signs of water.

Time Zones and ~
As a matter of civil convenience, the Earth is divided into various time zones. The time for many astronomical events is given in ~ (UT), which is (approximately) the local time for Greenwich, England---the Greenwich Mean Time or GMT.

False color has been used here to enhance the visibility of certain features in this composite of three images of the Minos Linea region on Jupiter's moon Europa taken on 28 June 1996 ~ by the Galileo spacecraft.

By mideclipse, more than an hour later, at 11:03 ~, 38-percent of the Moon's disk will be covered by the Earth's dark umbral shadow. At that time, the Moon will be overhead for observers in the South Pacific, but has already set for the northeastern U.S. and Canada.

Take note that the times on the IOTA page are all in ~ (UT), so you will need to correct for your local time zone. As an example, the disappearance of Aldebaran as seen from Philadelphia (listed as location 1342), occurs at 23:22:25 UT.

25, 2004 (that's in ~; it was Jan. 24 in California). The prime mission was planned to last 90 sols. NASA did not expect the rover to survive through a Martian winter. Sol 5,000 will begin early Friday, ~, with the 4,999th dawn a few hours later.

It became brightest when it passed closest to Earth at 13:44 ~, which is 8:44am Eastern US Time, and has been getting dimmer ever since.

coordinated ~/UTC, Greenwich Mean Time, julian date
solar day, sidereal day and solar day
sidereal period, synodic period
rotation and revolution
phase of the moon
magnitude, apparent magnitude, absolute magnitude, color ..

~ is defined as the local time (defined by the sun) at 0degrees longitude. This is also called Greenwich Mean Time. The local sidereal time is defined as the hour angle of the vernal equinox.

As with most astronomical data charts, times are in ~, or Greenwich Mean Time (GMT). To translate your time, visit the GMT website.
The U.S. Naval Observatory created a wonderful map that can assist in translating GMT. You can see it here (Adobe Acrobat Reader required).

The sequence of images shown above spans more than a nine hour period from 12:07 to 21:20 ~ (UT), (7:07am to 4:20pm central daylight savings time). The data include two M-class flares: an M6.4 flare starting at 13:53 UT and ending at 15:27 UT; and an M3.2 flare starting at 16:53 UT and ending at 18:01 UT.

For recording observations of static objects, such as deep sky, I suggest the use of local time, not ~ (U.T.). U.T. is more useful for timing dynamic events, such as occultations or eclipses, or for meteor shower counts.

So if it's not entropy, what may possibly be driving ~ in a forward direction?

Such a clock is located at the National Institute of Standards and Technology (NIST) in Boulder, Colorado. It forms the basis in the U.S. for Coordinated ~ (UTC), for which time signals are available by shortwave radio (stations WWV and WWVH), by telephone at 303.499.7111 or 900.410.

Cassini will conduct a critical 96-minute burn before going into orbit around Saturn on June 30 (July 1 ~). During Cassini's planned four-year tour it will conduct 76 orbits around the Saturn system and execute 52 close encounters with seven of Saturn's 31 known moons.

Greenwich Mean Time ' Time derived from the annual average movement of the sun over the zero degrees longitude position of the Greenwich Observatory in England. The mean is used in order to compensate for the Sun's non-uniform motion. It has since been replaced in astronomical circles by ~.
H ..

Universal Time Definition

The idea that a ~ can be used indiscriminately by all, irrespective of their varying states of motion--that is, by a person at rest at his home, by the driver of an automobile, and by the passenger aboard an airplane--is so deeply ingrained in most people that they do not even conceive of alternatives.

See also: What is the meaning of Astro, Earth, Sun, Planet, Solar?
◄ Uniform circular motion Unukalhai ►

Universal Time Clock

Coordinated Universal Time
Coordinated Universal Time (UTC) differs from international atomic time by an integral number of seconds and is the basis of most radio time systems and legal time systems.

Coordinated Universal Time. By international agreement, the local time at the prime meridian, which passes through Greenwich, England. Therefore, it is also known as Greenwich Mean Time, or sometimes simply Universal Time.

Coordinated Universal Time (UTC) - The primary time standard by which the world regulates clocks and time; UTC is one of several closely related successors to Greenwich Mean Time (GMT); for most common purposes, UTC is synonymous with GMT, although GMT is no longer precisely defined by the scientific community; ..

~ is a time standard based on International Atomic Time with leap seconds added at irregular intervals to compensate for the Earth's slowing rotation..
(UTC). UTC is derived from TAI, but synchronized, by using leap seconds, to UT1
Universal Time ..

~ (UTC). Civilization at large, not just astronomers, needs a smoothly running time system like Terrestrial Time. But most of humanity is also tied to the natural cycle of the day, variable though it may be. What to do?

Universal Time Definition

Universal Time Roblox Trello

~ (UTC)
Universal Time coordinated with ephemeris time; i.e., the rate is defined relative to atomic clock rate, but the epoch is defined relative to Universal Time. UTC is defined in such a manner that it differs from International Atomic Time (IAT) by an exact whole number of seconds.

~ (UTC)
January 3, 4 - Quadrantids Meteor Shower. Quadrantids Meteor Shower. The Quadrantids are an above average shower, with up to 40 meteors per hour at their peak. The shower usually peaks on January 3 & 4, but some meteors can be visible from January 1 - 5.

~: ~ (UTC) is a system we astronomers use. Also, times for us are usually converted to 24-hour time, i.e., 1 a.m. is 0100 hours, 1 p.m. is 1300 hours and so on. Mid-night or 12 a.m. is 0000 hours, not 2400.

~ (UTC): the time scale available from broadcast time signals. UTC differs from TAI (see International Atomic Time) by an integral number of seconds: it is maintained within ± 0.90 second of UT1 (see Universal Time) by the introduction of one second steps (leap seconds). (See leap second).
..

~ (UTC):
the time scale available from broadcast time signals. UTC differs from International Atomic Time (TAI) by an integral number of seconds; it is maintained within ±0$^{rm s}!!.$9 seconds of UT1 by the introduction of leap seconds.

~ (UTC) is a uniform ATOMIC TIME scale, based on caesium-beam atomic clocks; it is the basis of civil time. Because the Earth's rate of rotation is gradually slowing due to the effects of tidal braking, UTC and UT1 are gradually diverging.

According to the NASAEclipse Web Site, the total lunar eclipse on June 15, 2011 will begin at at 19:22:30 Universal Time (UT). However, according to astronomia.org, the total eclipse will begin at 19:22.5 ~ (UTC).
Universal Time or ~?

A location at which a particular coordinate system fails, such as the Schwarzschild metric coordinates at the Schwarzschild radius of a black hole. [HH98]
~ (UTC) ..

chosen to be the mean solar time at Greenwich, England (0 degrees longitude), and this time is called the Universal Time (UT). Due to physical processes such as mass motions in the atmosphere, the rate of rotation of the Earth varies from the mean solar time, and so a timescale called ~ ..

Longitude at a point may be determined by calculating the time difference between that at its location and ~ (UTC). Since there are 24 hours in a day and 360 degrees in a circle, the sun moves across the sky at a rate of 15 degrees per hour (360°/24 hours = 15° per hour).

This calendar was used in conjunction with the ~ standard (UTC) to give a single value for timekeeping all over the planet. UTC was adopted throughout the Solar System at first, but once permanent colonies were established on the Moon and Mars new calendars were established for those worlds.

In 1972 a new timekeeping system was adopted: ~, or UTC, based on an atomic clock. The idea is that atoms are pretty good timekeepers, and in particular a cesium atom makes an excellent clock (I describe why here).

A leap second is a second added to ~ (UTC) to make it agree with astronomical time to within 0.9 second. UTC is an atomic time scale, based on the performance of atomic clocks. Astronomical time is based on the rate of rotation of the earth.

~/UTC, Greenwich Mean Time, julian date
solar day, sidereal day and solar day
sidereal period, synodic period
rotation and revolution
phase of the moon
magnitude, apparent magnitude, absolute magnitude, color ..

0505 January 25 UTC ~ or GMT
Meridiani Planum is halfway around the planet from Gusev Crater, where its twin, Spirit, landed. The soil at Meridiani Planum has an ancient layer of hematite. On Earth, that iron oxide almost always forms in an environment containing liquid water.

Such a clock is located at the National Institute of Standards and Technology (NIST) in Boulder, Colorado. It forms the basis in the U.S. for ~ (UTC), for which time signals are available by shortwave radio (stations WWV and WWVH), by telephone at 303.499.7111 or 900.410.

UT is usually used for astronomical observations, while Terrestrial Dynamical Time (TDT, or simply TT) is used in orbital and ephemeris computations that involve geocentric computations. ~ (UTC) is that used for broadcast time signals (available via shortwave radio, for example), ..

(To learn more about that go to this page and scroll down to the part about the Earth-Moon System.) Actually, the leap second winds up at midnight only if you really observe UTC time. If I were anal enough to synch my computer's clock precisely to the U. S. Naval Observatory's ~, ..

~ (UTC) is that used for broadcast time signals (available via shortwave radio, for example), and it is within a second of UT.
UNIVERSE: In astronomy, the sum total of all things which can be directly observed or whose physical effects on other things can be detected.

See also: What is the meaning of Universal Time, Earth, Sun, Astro, Solar?
◄ Coordinate Systems Copernican revolution ►