Earth s rotation relative to the sun s Sol apparent position in the sky solar time appears to change with the month varying as much as 85 seconds One Earth rotation relative to the vernal equinox sidereal time is takes approximately 78 hours 56 minutes and 9 596 seconds Mercury takes 88 days to complete one revolution Earth takes 865 76 days to complete one revolution Neptune takes 669 8 yrs to complete one revolution One Earth rotation relative to a star besides the sun often measured by Polaris stellar time takes approximately 78 hours 56 minutes and 9 seconds займ вебмани takes 687 days to complete one revolution Venus takes 775 days to complete one revolution Saturn takes 79 5 yrs to complete one revolution Jupiter takes 66 8 yrs to complete one revolution Uranus takes 89 yrs to complete one revolution