AnnaOgg388928: minor enhanced section for accuracy additionally and added references for consistency

2026-05-07T12:48:29Z

minor enhanced section for accuracy additionally and added references for consistency

← Older revision		Revision as of 18:18, 7 May 2026
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	== Computer systems ==		== Computer systems ==
	Many computer [[operating systems]] include the necessary support for working with ~~all~~ many or all possible local times. Internally, operating systems typically use [[Coordinated Universal Time\|UTC]] as their basic [[system time\|time-keeping standard]] and convert local times, including [[daylight savings time]], to and from UTC.		Many computer [[operating systems]] include the necessary support for working with many or all possible local times. Internally, operating systems typically use [[Coordinated Universal Time\|UTC]] as their basic [[system time\|time-keeping standard]] and convert local times, including [[daylight savings time]], to and from UTC.

	Web servers presenting web pages primarily for an audience in a single time zone or a limited range of time zones typically show times as a local time, perhaps with UTC time in brackets. More internationally oriented websites may show times in UTC only or using an arbitrary time zone. For example, the international English-language version of CNN includes GMT and Hong Kong Time,<ref>{{cite web \|url=http://edition.cnn.com \|title=International CNN \|publisher=CNN \|access-date=December 5, 2011 \|archive-date=March 10, 2018 \|archive-url=https://web.archive.org/web/20180310195324/https://edition.cnn.com/ \|url-status=live }}</ref> whereas the US version shows [[Eastern Time Zone\|Eastern Time]].<ref>{{cite web \|url=http://www.cnn.com \|title=United States CNN \|publisher=Cnn.com \|access-date=December 5, 2011 \|archive-date=September 11, 2001 \|archive-url=https://web.archive.org/web/20010911200318/http://www.cnn.com/ \|url-status=live }}</ref>{{needs update\|date=January 2026}}US Eastern Time and [[Pacific Time Zone\|Pacific Time]] are also used fairly commonly on many US-based English-language websites with global readership. The format is typically based in the [[World Wide Web Consortium\|W3C]] Note "datetime".		Web servers presenting web pages primarily for an audience in a single time zone or a limited range of time zones typically show times as a local time, perhaps with UTC time in brackets. More internationally oriented websites may show times in UTC only or using an arbitrary time zone. For example, the international English-language version of CNN includes GMT and Hong Kong Time,<ref>{{cite web \|url=http://edition.cnn.com \|title=International CNN \|publisher=CNN \|access-date=December 5, 2011 \|archive-date=March 10, 2018 \|archive-url=https://web.archive.org/web/20180310195324/https://edition.cnn.com/ \|url-status=live }}</ref> whereas the US version shows [[Eastern Time Zone\|Eastern Time]].<ref>{{cite web \|url=http://www.cnn.com \|title=United States CNN \|publisher=Cnn.com \|access-date=December 5, 2011 \|archive-date=September 11, 2001 \|archive-url=https://web.archive.org/web/20010911200318/http://www.cnn.com/ \|url-status=live }}</ref>{{needs update\|date=January 2026}}US Eastern Time and [[Pacific Time Zone\|Pacific Time]] are also used fairly commonly on many US-based English-language websites with global readership. The format is typically based in the [[World Wide Web Consortium\|W3C]] Note "datetime".
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	== Time in outer space ==		== Time in outer space ==
	Orbiting spacecraft may experience many sunrises and sunsets, or none, in a 24-hour period. Therefore, it is not possible to calibrate the time with respect to the Sun and still respect a 24-hour sleep/wake cycle. A common practice for [[space exploration]] is to use the Earth-based time of the launch site or mission control, synchronizing the sleeping cycles of the crew and controllers. The [[International Space Station]] normally uses ~~Greenwich Mean~~ Time (~~GMT~~).<ref>{{~~cite web~~\|title=~~Ask~~ the ~~Crew: STS-111~~\|url=~~http~~://www.~~spaceflight.nasa~~.~~gov~~/~~feedback~~/~~expert/answer/crew/sts~~-~~111/index.html\|publisher=National Aeronautics and Space Administration\|date=June 19, 2002\|access~~-~~date=September 10, 2015\|archive~~-~~date=September 28, 2015\|archive~~-~~url=https://web.archive.org/web/20150928070925/http://spaceflight.nasa.gov/feedback/expert/answer/crew/sts~~-~~111/index.html\|url~~-~~status=dead}}</ref><ref>{{cite web\|title=Day in~~ the ~~Life\|url=http://spaceflight.nasa.gov/~~station/~~crew/exp7/luletters/lu_letter9.html\|last=Lu\|first=Ed\|publisher=National Aeronautics and Space Administration\|date=September 8, 2003~~\|access-date=~~September 10, 2015\|archive-date=September 1, 2012\|archive-url=https://web.archive.org/web/20120901183936/http://spaceflight.nasa.gov/station/crew/exp7/luletters/lu_letter9.html~~\|~~url-status~~=~~dead~~}}</ref>		Orbiting spacecraft may experience many sunrises and sunsets, or none, in a 24-hour period. Therefore, it is not possible to calibrate the time with respect to the Sun and still respect a 24-hour sleep/wake cycle. A common practice for [[space exploration]] is to use the Earth-based time of the launch site or mission control, synchronizing the sleeping cycles of the crew and controllers. The [[International Space Station]] normally uses [[Coordinated Universal Time]] (UTC).<ref>{{Cite magazine \|last=Mitchell \|first=Gareth \|title=What time zone do they use on the International Space Station? \|url=https://www.sciencefocus.com/space/what-time-zone-do-they-use-on-the-international-space-station/ \|access-date=29 April 2026 \|magazine=[[BBC Science Focus]]}}</ref>

	[[Timekeeping on Mars]] can be more complex, since the planet has a solar day of approximately 24 hours and 40 minutes, known as a [[Sol (day on Mars)\|sol]]. Earth controllers for some Mars missions have synchronized their sleep/wake cycles with the Martian day, when specifically solar-powered rover activity occurs.<ref>{{cite web \|url=https://www.space.com/17815-mars-rover-jet-lag.html \|title=New Tricks Could Help Mars Rover Team Live on Mars Time \|author=Megan Gannon \|website=Space.com \|date=September 28, 2012 \|access-date=November 21, 2024 \|archive-date=November 21, 2024 \|archive-url=https://web.archive.org/web/20241121215156/https://www.space.com/17815-mars-rover-jet-lag.html \|url-status=live }}</ref>		[[Timekeeping on Mars]] can be more complex, since the planet has a solar day of approximately 24 hours and 40 minutes, known as a [[Sol (day on Mars)\|sol]]. Earth controllers for some Mars missions have synchronized their sleep/wake cycles with the Martian day, when specifically solar-powered rover activity occurs.<ref>{{cite web \|url=https://www.space.com/17815-mars-rover-jet-lag.html \|title=New Tricks Could Help Mars Rover Team Live on Mars Time \|author=Megan Gannon \|website=Space.com \|date=September 28, 2012 \|access-date=November 21, 2024 \|archive-date=November 21, 2024 \|archive-url=https://web.archive.org/web/20241121215156/https://www.space.com/17815-mars-rover-jet-lag.html \|url-status=live }}</ref>

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2026-03-25T04:48:07Z

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92.28.48.135 at 18:31, 5 March 2020

2020-03-05T18:31:36Z

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[[File:World Time Zones Map.png|thumb|400px|Standard World Time Zones map (as of August 2015)]]
'''Time zones''' give specific areas on the [[Earth]] a [[time]] of [[day]] that is earlier or later than the neighboring time zones. This is because when it is daytime on one side of the earth, it is night-time on the other side. There are 24 time zones dividing the earth into different times, each with its own name, like the [[North American Eastern Time Zone]]. The North American Eastern Time Zone contains large cities in [[North America]] like [[New York City]] and [[Miami]].

[[Greenwich Mean Time]] (GMT) began in 1675. This was when the [[Royal Observatory, Greenwich]] was built to help ships find their longitude at sea. GMT was a standard reference for time keeping when each city kept a different local time. When railways began carrying many people quickly among cities keeping different time, they adopted time zones to simplify operations. By about 1900, almost all time on earth was in the form of standard time zones.

Greenwich Mean Time is now called UTC ([[Coordinated Universal Time]]). UTC is the time standard of the world. All other parts of the world are offset (plus or minus) according to their longitude. Most of the zones are offset by a full hour, but there are some offset by half an hour or 45 minutes.

In some parts of the world they follow the [[Daylight Saving Time]] (DST), and during this period of time in summer they add one hour to their normal solar hour.

In the [[Geographical pole|poles]], the time is UTC in the [[North Pole]] and UTC+12 in the [[South Pole]].

The time zones are numbered in relation to the UTC, so in [[Los Angeles]] the time zone will be UTC−8, in [[London]] UTC+0, in [[Rome]] UTC+1, and in [[New Delhi]] UTC+5:30.

{{sci-stub}}

[[Category:Time zones| ]]

Time zone - Revision history

AnnaOgg388928: minor enhanced section for accuracy additionally and added references for consistency

TiaBurwell25: improved article

WikiDwarf: 1 revision imported

92.28.48.135 at 18:31, 5 March 2020