The time taken for the earth to complete one revolution on its axis. The solar day is the interval between two successive returns of the sun to the meridian. The mean solar day of 24 hours is the average value of the solar day for one year. The sidereal day is measured with respect to the fixed stars and is 4.09 minutes shorter than the mean solar day as a result of the imposition of the earth's orbital motion on its rotational motion.
Subjects: Science and Mathematics.