Tidsinndeling

Tidsinndeling refers to the division of time into smaller, manageable units. This concept is fundamental to human civilization, allowing for organization, planning, and the coordination of activities. The most common and widely recognized system of tidsinndeling is based on the Earth's rotation and orbit around the sun.

The day is the primary unit, defined by the Earth's rotation on its axis. A day is conventionally divided into 24 hours. An hour is further subdivided into 60 minutes, and each minute into 60 seconds. This sexagesimal system for hours, minutes, and seconds has ancient origins, stemming from Babylonian and Egyptian mathematics.

The week, a period of seven days, is another widely adopted unit. Its origin is often linked to ancient religious practices and celestial observations, particularly the seven visible celestial bodies known in antiquity: the Sun, Moon, Mars, Mercury, Jupiter, Venus, and Saturn.

The month is broadly based on the lunar cycle, the time it takes for the Moon to complete one orbit around the Earth. However, modern calendars, like the Gregorian calendar, have standardized month lengths to align with the solar year.

The year, representing the Earth's revolution around the sun, is the basis for our annual calendar. It is approximately 365.25 days long, leading to the concept of leap years to account for the fractional part. Larger divisions of time, such as decades (10 years), centuries (100 years), and millennia (1000 years), are also part of tidsinndeling, facilitating historical periodization and long-term planning. The accurate measurement and standardized division of time are essential for science, commerce, and daily life.