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How long does Earth take to orbit the Sun?
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Earth
A composite image of Earth captured by instruments aboard NASA's Suomi National Polar-orbiting Partnership satellite, 2012.
Earth takes approximately 365.2422 days to complete one orbit around the Sun.1
Because this duration is not a whole number of days, calendars require adjustments to remain in sync with the seasons. In astronomy, the length of an orbit can be defined in several ways, leading to slightly different measurements:21
- Tropical year: The interval between successive passages of the Sun through the vernal equinox, which is approximately 365.2422 days (or 365 days, 5 hours, 48 minutes, and 46 seconds).231
- Sidereal year: The time taken for the Sun to return to the same position relative to the background stars, lasting about 365 days, 6 hours, 9 minutes, and 10 seconds.2
- Anomalistic year: The time between two successive passages of Earth through perihelion, lasting about 365 days, 6 hours, 13 minutes, and 53 seconds.2