Day
A day is the time it takes the Earth to spin around once. It is daytime on the side of the Earth that is facing the Sun. When it is nighttime, that side of the Earth is facing away from the Sun. It takes 24 hours for the Earth to spin once, so that is one day, including the daytime and nighttime. This is mean solar time, measured relative to the Sun. There is also sidereal time, measured relative to the fixed stars. The sidereal day is a few minutes shorter.
List of days of the year
* There are only 29 days in February during a leap year. Otherwise, February has 28 days.
| Days of the Week |
|---|
| Sunday | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday |
Day Media
Earth's rotation imaged by Deep Space Climate Observatory, showing axis tilt
Rotation of the dwarf planet Ceres
Decimal clock face, made in around the start of the 19th century
Sun and Moon, Hartmann Schedel's Nuremberg Chronicle, 1493
Twilight-dawn subcategories
Related pages
Other websites
- Day -Citizendium
Authority: International System of Units (BIPM) | ||
| Base units |  | |
| Units based on base units | ||
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