Noon

Noon
Alexey Bogolyubov · Public domain · source
Name	Noon
Alternative names	Midday, 12:00, High Noon
Time of day	Approximately 12:00 local solar time
Related	Solar noon, Meridian (astronomy), Time zone, Greenwich Mean Time

Noon is the time of day commonly associated with 12:00 by civil clocks and with the Sun's highest apparent altitude in the sky at solar noon. Across cultures and calendars, noon functions as a temporal anchor for daily schedules, liturgical hours, legal deadlines, navigation, and astronomical observations. Historical practices, religious rites, linguistic idioms, and technological standards have all treated noon as a focal point linking local solar phenomena to standardized timekeeping systems.

Etymology

The English term derives from Old English nōn, from Latin nona hora via Ecclesiastical Latin and early Christian liturgy traditions where the "ninth hour" marked a canonical prayer time. The transmission involved institutions such as the Roman Empire, Byzantine Empire, and Catholic Church, influencing vernaculars across Anglo-Saxon England and medieval Western Europe. Related terms in Romance languages, for example Italian language and Spanish language, reflect the same liturgical origin through words like mezzogiorno and mediodía influenced by regional religious practice and monastic schedules charted in manuscripts of Benedictine communities.

Definitions and Timekeeping

Noon is commonly defined in two distinct ways: civil noon (12:00 on a legal clock) and solar noon (when the Sun crosses a local meridian). Civil noon ties to standards set by institutions such as International Meridian Conference outcomes, Greenwich Observatory measurements, and national time zone regulations influenced by the expansion of railways and telegraphy in the 19th century, notably involving organizations like the Great Western Railway and governments of United Kingdom and United States. Solar noon depends on geographical coordinates and the equation of time derived by astronomers working at observatories such as Royal Greenwich Observatory, Paris Observatory, and United States Naval Observatory. Coordinated Universal Time, established by the International Telecommunication Union and International Bureau of Weights and Measures, mediates civil definitions across jurisdictions including European Union member states and countries using Standard time legislated by national parliaments.

Cultural and Religious Significance

Noon occupies prominent roles in religious rites and civic rituals spanning institutions like the Catholic Church, Eastern Orthodox Church, Islam, and Judaism. Christian canonical hours such as None and Sext historically structured monastic life in Benedictine Rule monasteries and cathedral chapters in Canterbury and Chartres. In Islamic practice, the Duhr prayer occurs after the Sun passes its zenith, a timing regulated in part by rulings from juridical councils and synods across regions including Iraq and Arabian Peninsula. Jewish midday observances—such as those tied to the reading cycles established by scholars from Babylonian Talmud traditions in centers like Sura and Pumbedita—reference the Sun's position for halakhic determinations. Civic customs—marked by institutions such as municipal authorities in Paris, Rome, and Beijing—include bell ringing at midday from cathedrals like Notre-Dame de Paris and civic noon guns fired historically by arsenals like the Tower of London and ports managed by British Admiralty.

Scientific and Astronomical Aspects

Astronomers and navigators define solar noon as the instant the Sun crosses the observer's meridian, a phenomenon predicted using models developed by figures such as Johannes Kepler, Isaac Newton, and astronomers at Royal Greenwich Observatory. Calculations account for Earth's axial tilt, orbital eccentricity, and perturbations described by the work of Pierre-Simon Laplace and contemporary ephemerides from agencies like Jet Propulsion Laboratory and European Space Agency. Solar noon varies with longitude and season; correction terms—derived from the equation of time and coordinate transformations used by astronomical almanac compilers such as the U.S. Naval Observatory—enable precise timing for celestial navigation employed historically on voyages by HMS Beagle and in modern satellite tracking by Global Positioning System networks administered by United States Department of Defense.

Noon in Language and Idioms

Noon has generated idioms and cultural metaphors preserved in literature and media linked to authors and productions such as William Shakespeare, Mark Twain, and the film High Noon. Phrases referencing midday recur in political speeches and journalism associated with institutions like The Times (London), The New York Times, and broadcasting outlets including BBC and CBS. Literary usages by writers influenced by historical milieus—such as scenes in Les Misérables set near Notre-Dame de Paris or descriptions in travelogues by explorers like Marco Polo—encode noon as a narrative pivot for action, decision, and climax.

Historical Practices and Noon Landmarks

Public time signals and landmarks for midday evolved through technologies and sites like church clocks installed in Westminster Abbey, noon cannons at Zürich and Gibraltar, and time balls at observatories such as Greenwich and Sydney Observatory. The adoption of standard time zones followed conferences and legislation in cities like Chicago and Washington, D.C. driven by railroad companies including Atchison, Topeka and Santa Fe Railway and figures such as Sir Sandford Fleming. Urban designs—exemplified by sundials on structures in Florence and plazas in Madrid—served as civic indicators of noon for merchants and guilds tied to institutions like medieval Hanoverian trade networks. Contemporary heritage sites preserving these practices include museological exhibits at Science Museum, London and historic observatories operated by national academies such as the Royal Society.

Category:Time