Solartid

Solartid, also known as solar time, is a system of timekeeping that is based on the apparent position of the Sun in the sky. In its most basic form, noon in solar time is defined as the moment the Sun reaches its highest point in the sky, known as local apparent noon. This position can be determined by observing the Sun's shadow. The length of a solar day, the time it takes for the Sun to appear in the same position in the sky, is not constant throughout the year. This variation is due to the Earth's elliptical orbit around the Sun and the tilt of its axis.

To address this variability, mean solar time was developed. Mean solar time uses an average solar day, assuming a constant rate of Earth's rotation. This smoothed-out time is what is used in most modern timekeeping. Standard time zones, which divide the Earth into roughly equal longitudinal segments, are based on mean solar time to create a more practical and uniform system of timekeeping across larger geographical areas. Without standard time zones, the time in every town would be different based on its exact longitude. Therefore, solartid, in its historical and conceptual sense, is the foundation upon which our modern, albeit standardized, timekeeping is built.