Day - Boundaries of the day - Article Index

Encyclopedia - Day: Encyclopedia - Day
A day (symbol: d) is a unit of time equal to 24 hours. It is not an SI unit but it is accepted for use with SI. The SI unit of time is th...   » Read the article

Encyclopedia - Day: Encyclopedia Ii - Day - Boundaries Of The Day
For most diurnal animals, including Homo sapiens, the day naturally begins at dawn and ends at sunset. Humans, with our cultural norms an...   » Read the article

Encyclopedia - Day: Encyclopedia Ii - Day - Introduction
Different definitions of the day are based on the apparent motion of the Sun across the sky (solar day; see solar time). The reason for t...   » Read the article

Encyclopedia - Day: Encyclopedia Ii - Day - Civil Day
For civil purposes a common clock time has been defined for an entire region based on the mean local solar time at some central meridian....   » Read the article

Encyclopedia - Day: Encyclopedia Ii - Day - Definition Of A Day In Astronomy
For a given planet, there are two types of day defined in astronomy: 1 apparent sidereal day = a single rotation of a planet with respect...   » Read the article

Encyclopedia - Day: Encyclopedia Ii - Day - Leap Seconds
In order to keep the civil day aligned with the apparent movement of the Sun, positive or negative leap seconds may be inserted. A civil ...   » Read the article