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Information about Noon

Noon is 12:00 at midday. Contrary to popular belief, it is not the moment when the sun crosses the meridian. The sun does cross the meridian at noon, apparent solar time, but we live by civil time (which is either Standard Time or Daylight Saving Time depending on the time of year and local laws) which is not the same as apparent solar time. Midday is also used as a synonym for noon, although this may also be a more general term to mean around noon, or very early afternoon.

Confusion between a.m. and p.m. when referring to noon and midnight

Main article: 12-hour clock#Confusion at noon and midnight
Digital clocks and computers show 12 p.m. for noon. While that phrase may be used practically, it helps to understand that any particular time is actually an instant. The "p.m." shown on clock displays refers to the 12-hour period following the instant of noon, not to the instant itself. In other words, 11:59 a.m. shows until noon; at the instant of noon it flips to 12:00. Simultaneously, the a.m. flips to p.m., though, strictly speaking, p.m. applies not to the instant of noon which separates a.m. and p.m.

Most people in North America, though, assume that 12 a.m. and 12 p.m. signify noon and midnight, respectively. The confusion also comes from 12 a.m. seeming to be the next hour in the 10 a.m., 11 a.m. series, but 12.01 p.m. being just after noon. In addition, p.m. is often associated with night so 12 p.m. may seem to be midnight.

Etymologically speaking, a.m. means before noon (antemeridiem) and p.m. means after noon (postmeridiem) and so neither midday nor midnight are correctly referred to using a.m. or p.m..

Solar noon

Solar noon is when the sun appears the highest in the sky (nearest zenith), compared to its positions during the rest of the day. It occurs when the Sun is transitting the celestial meridian. This is also the origin of the terms ante meridiem and post meridiem as noted above. The Sun is directly overhead at solar noon at the equator on the equinoxes; at Tropic of Cancer (latitude 23½°N) on the June solstice; and at Tropic of Capricorn (23½°S) on the December solstice. Due to the effects of the use of standard time, daylight saving time, and the equation of time, clock noon and solar noon hardly ever coincide.

The opposite of noon is midnight.

Etymology

The word "noon" is derived from Latin nona hora, the ninth hour of the day. As the Roman day started on 6.00 a.m., at sunrise, the first hour would have been from 6.00 till 7.00 a.m and the ninth hour from 2.00 till 3.00 p.m. These hours were important in monasteries, as different prayers were held on them.

The English word "noon" originally applied at 3.00 p.m., but by 1100 AD the meaning had shifted to "midday". (see: [1])

See also

External link

For the taxonomical term, see .


Synonyms (in ancient Greek, συν ("syn") = plus and όνομα ("onoma") = name
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  • Afternoon is the time of day from 12:00 (noon) to -- depending upon context -- evening, sunset, or 4:00 or 6:00 pm. Its use is often quite subjective.
  • In Australia, the word "arvo" has the same meaning as afternoon.

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Midnight is, literally, "the middle of the night." In most systems it is when one day ends and the next begins: when the date changes. Originally midnight was halfway between sunset and dawn, varying according to the seasons.
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Etymology is the study of the history of words - when they entered a language, from what source, and how their form and meaning have changed over time.

In languages with a long written history, etymology makes use of philology, the study of how words change from culture to
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The Sun

Observation data
Mean distance
from Earth 1.4961011 m
(8.31 min at light speed)
Visual brightness (V) −26.74m [1]
Absolute magnitude 4.
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zenith is the direction pointing directly above a particular location (perpendicular, orthogonal). Since the concept of being above is itself somewhat vague, scientists define the zenith in more rigorous terms.
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The term transit or astronomical transit has two meanings in astronomy:
  • A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, as seen by an observer at some particular vantage

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Astronomy is the scientific study of celestial objects (such as stars, planets, comets, and galaxies) and phenomena that originate outside the Earth's atmosphere (such as the cosmic background radiation).
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meridian is an imaginary great circle on the celestial sphere. It passes through the north point on the horizon, through the celestial pole, up to the zenith, through the south point on the horizon, and through the nadir, and is perpendicular to the local horizon.
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The 12-hour clock is a timekeeping convention in which the 24 hours of the day are divided into two periods called ante meridiem (a.m., from Latin, meaning "before mid day", or "before the middle of the day") and post meridiem (
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The 12-hour clock is a timekeeping convention in which the 24 hours of the day are divided into two periods called ante meridiem (a.m., from Latin, meaning "before mid day", or "before the middle of the day") and post meridiem (
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equator is an imaginary line on the Earth's surface equidistant from the North Pole and South Pole. It thus divides the Earth into a Northern Hemisphere and a Southern Hemisphere. The equators of other planets and astronomical bodies are defined analogously.
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equinox can have two meanings:
  • The moment when the Sun is positioned directly over the Earth's equator and, by extension, the apparent position of the Sun at that moment - see below.

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Tropic of Cancer, or Northern tropic, is one of the five major circles of latitude that mark maps of the Earth. It is the most northerly latitude at which the sun can appear directly overhead at noon.
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equator divides the planet into a Northern Hemisphere and a Southern Hemisphere, and has a latitude of 0. Latitude, usually denoted symbolically by the Greek letter phi, , gives the location of a place on Earth north or south of the equator.
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solstice occurs twice a year, whenever Earth's axis tilts the most toward or away from the Sun, causing the Sun to be farthest north or south at noon. The name is derived from Latin sol (sun) and sistere
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Tropic of Capricorn, or Southern tropic, is one of the five major circles of latitude that mark maps of the Earth. It lies 23° 26′ 22″ south of the Equator, and marks the most southerly latitude at which the sun can appear directly overhead at noon.
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Standard time is the result of synchronizing clocks in different geographical locations within a time zone to the same time rather than using the local meridian as in local mean time or solar time. The time so set has come to be defined in terms of offsets from Universal Time.
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Daylight saving time (DST; also summer time in British English) is the convention of advancing clocks so that afternoons have more daylight and mornings have less.
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equation of time is the difference, over the course of a year, between time as read from a sundial and a clock. The sundial can be ahead (fast) by as much as 16 min 33 s (around November 3) or fall behind by as much as 14 min 6 s (around February 12).
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Antonyms, from the Greek anti ("opposite") and onoma ("name") are word pairs that are opposite in meaning, such as hot and cold, obese and skinny, and up and down.
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Midnight is, literally, "the middle of the night." In most systems it is when one day ends and the next begins: when the date changes. Originally midnight was halfway between sunset and dawn, varying according to the seasons.
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A dipleidoscope is an instrument used to determine true noon. It consists of a small telescope and a prism that creates a double image of the sun. When the two images overlap, it is local true noon. The instrument is capable of determining true noon to within ten seconds.
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Midnight is, literally, "the middle of the night." In most systems it is when one day ends and the next begins: when the date changes. Originally midnight was halfway between sunset and dawn, varying according to the seasons.
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The 12-hour clock is a timekeeping convention in which the 24 hours of the day are divided into two periods called ante meridiem (a.m., from Latin, meaning "before mid day", or "before the middle of the day") and post meridiem (
..... Click the link for more information.


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