What is the Earth's orbital period around the sun?

The orbital period of the Earth, known as the sidereal year, is the time taken for the Sun (as observed from the Earth) to return to the same position with respect to the stars of the celestial sphere. It is equal to 365.25636042 mean solar days (31,558,149.540 seconds), that is 366.25636042 earth rotations or sidereal days. The sidereal year is 20 minutes and 24 seconds longer than the tropical year, the year of the four seasons. The word "sidereal" means "relating to the stars". It derives from the Latin sidus, meaning "star".