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How long is a day on Mars?
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Mars
An especially serene view of Mars (Tharsis side), a composite of images taken by the Mars Global Surveyor spacecraft in April 1999. The northern polar cap and encircling dark dune field of Vastitas Borealis are visible at the top of the globe. White water-ice clouds surround the most prominent volcanic peaks, including Olympus Mons near the western limb, Alba Patera to its northeast, and the line of Tharsis volcanoes to the southeast. East of the Tharsis rise can be seen the enormous near-equatorial gash that marks the canyon system Valles Marineris.
The length of a day on Mars depends on whether you are measuring by the planet's rotation relative to the stars or the time between sunrises.
- Martian sidereal day: The time it takes for Mars to complete one rotation on its axis is 24 hours, 37 minutes, and 22.663 seconds.1
- Martian mean solar day (sol): The time between successive sunrises is 24 hours, 39 minutes, and 36 seconds.1
Because these durations are very close to the length of an Earth day, Mars experiences a diurnal cycle that is only slightly longer than our own.21