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day

Also known as days, Earth day

A day is the time period of a full rotation of the Earth with respect to the Sun. On average, this is 24 hours (86,400 seconds). As a day passes at a given location it experiences morning, afternoon, evening, and night. This daily cycle drives circadian rhythms in many organisms, which are vital to many life processes.

AI overview

A day is the 24-hour period it takes for Earth to complete one full rotation relative to the Sun, during which a location experiences morning, afternoon, evening, and night. This daily cycle is important because it drives circadian rhythms in many organisms, which are essential to vital life processes.

AI-generated from the Wikipedia summary — may contain errors.

~16 min read

Encyclopedic overview

19 sections

Contents

Etymology
Definitions
Apparent and mean solar day
Civil day
Sidereal day{{anchor|Extraterrestrial bodies}}
In the International System of Units
In decimal and metric time
Other definitions
Variations in length
Geological day lengths
Boundaries
Parts
Daytime
Twilight
Night
In other cultures
See also
References
External links

A collection of sequential days is organized into calendars as dates, almost always into weeks, months and years. A solar calendar organizes dates based on the Sun's annual cycle, giving consistent start dates for the four seasons from year to year. A lunar calendar organizes dates based on the Moon's lunar phase.

Excerpted from Wikipedia’s “day” article, available under the CC BY-SA 4.0 licence.