Astronomical Year Guide

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.

The time between two consecutive perihelion passages (the closest point to the sun) (approx. 365.2596365.2596 astronomical year

An exact, averaged time unit used in astronomy for long-term calculations, defined as 365.25365.25 seconds each. 2. Key Differences in Measurements The Gregorian calendar

There are several ways to define a "year," depending on what reference point is used for a full orbit: astronomical year