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  2. Timekeeping on Mars - Wikipedia

    en.wikipedia.org/wiki/Timekeeping_on_Mars

    Definition of year and seasons. The length of time for Mars to complete one orbit around the Sun in respect to the stars, its sidereal year, is about 686.98 Earth solar days (≈ 1.88 Earth years), or 668.5991 sols. Because of the eccentricity of Mars' orbit, the seasons are not of equal length.

  3. Sidereal year - Wikipedia

    en.wikipedia.org/wiki/Sidereal_year

    Sidereal year. A sidereal year (/ saɪˈdɪəri.əl /, US also / sɪ -/; from Latin sidus 'asterism, star'), also called a sidereal orbital period, is the time that Earth or another planetary body takes to orbit the Sun once with respect to the fixed stars. Hence, for Earth, it is also the time taken for the Sun to return to the same position ...

  4. Rotation period (astronomy) - Wikipedia

    en.wikipedia.org/wiki/Rotation_period_(astronomy)

    Rotation period (astronomy) In astronomy, the rotation period or spin period[1] of a celestial object (e.g., star, planet, moon, asteroid) has two definitions. The first one corresponds to the sidereal rotation period (or sidereal day), i.e., the time that the object takes to complete a full rotation around its axis relative to the background ...

  5. Mars sol - Wikipedia

    en.wikipedia.org/wiki/Mars_sol

    The average duration of the day-night cycle on Mars — i.e., a Martian day — is 24 hours, 39 minutes and 35.244 seconds, [3] equivalent to 1.02749125 Earth days. [4] The sidereal rotational period of Mars—its rotation compared to the fixed stars—is 24 hours, 37 minutes and 22.66 seconds. [4]

  6. Sidereal time - Wikipedia

    en.wikipedia.org/wiki/Sidereal_time

    Animation showing the difference between a sidereal day and a solar day. Sidereal time ("sidereal" pronounced / saɪˈdɪəriəl, sə -/ sy-DEER-ee-əl, sə-) is a system of timekeeping used especially by astronomers. Using sidereal time and the celestial coordinate system, it is easy to locate the positions of celestial objects in the night sky.

  7. Orbit of Mars - Wikipedia

    en.wikipedia.org/wiki/Orbit_of_Mars

    Mars has an orbit with a semimajor axis of 1.524 astronomical units (228 million km) (12.673 light minutes), and an eccentricity of 0.0934. [1][2] The planet orbits the Sun in 687 days [3] and travels 9.55 AU in doing so, [4] making the average orbital speed 24 km/s. The eccentricity is greater than that of every other planet except Mercury ...

  8. Elongation (astronomy) - Wikipedia

    en.wikipedia.org/wiki/Elongation_(astronomy)

    where T e and T p are Earth's and the planet's years (i.e. periods of revolution around the Sun, called sidereal periods). For example, Venus's year (sidereal period) is 225 days, and Earth's is 365 days. Thus Venus's synodic period, which gives the time between every two eastern greatest elongations, is 584 days; this also applies to the ...

  9. Historical models of the Solar System - Wikipedia

    en.wikipedia.org/wiki/Historical_models_of_the...

    where a is the radius of the orbit, T is the period, G is the gravitational constant and M is the mass of the Sun. The third law explains the periods that occur during the year which relates the distance between the Earth and the Sun. [75] Along with unprecedent accuracy, the Keplerian model also allows put the Solar System into scale.