Astronomical Year -

Ancient cultures, including the Greeks, noticed the slow drift of equinoxes, leading to the identification of the precession of the Earth’s axis. How long is a year on other planets? - Astronomy Magazine

The time between two vernal equinoxes (approx. 365.24219365.24219 days). This dictates our seasons and calendars. Sidereal Year: The time taken for Earth to complete one 360∘360 raised to the composed with power orbit relative to the fixed stars (approx. 365.25636365.25636 astronomical year

The Gregorian calendar, used worldwide, incorporates leap years (adding a day every four years) to keep our 365-day calendar in sync with the 365.24219-day tropical year. Ancient cultures, including the Greeks, noticed the slow