Päikeseaega

Päikeseaega, which translates to "sun time" or "solar time" in English, is a way of measuring time based on the apparent position of the Sun in the sky. Historically, it was the primary method of timekeeping before the advent of mechanical clocks and standardized time zones. Solar time is determined by the Sun's highest point in the sky, which corresponds to local apparent noon. This point marks the moment when the Sun crosses the local meridian.

The length of a solar day is not constant throughout the year. This variation is due to two main factors: the Earth's elliptical orbit around the Sun and the tilt of the Earth's axis. The Earth moves faster in its orbit when it is closer to the Sun and slower when it is farther away. Additionally, the axial tilt causes the Sun's apparent path across the sky to change seasonally. These irregularities mean that the duration of a solar day can vary by up to about 16 minutes over the course of a year.

To address this inconsistency, astronomers developed mean solar time. Mean solar time is based on a hypothetical average solar day, which is precisely 24 hours long. This concept allows for a uniform and consistent measurement of time, which is essential for navigation, scientific calculations, and the functioning of modern society. The difference between apparent solar time and mean solar time is accounted for by the equation of time, a value that shows the discrepancy between the two. Even with the standardization of time zones, the underlying principles of solar time continue to influence our understanding and measurement of days and years.