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  2. Voyager 2 - Wikipedia

    en.wikipedia.org/wiki/Voyager_2

    The length of a day on Uranus as measured by Voyager 2 is 17 hours, 14 minutes. [49] Uranus was shown to have a magnetic field that was misaligned with its rotational axis, unlike other planets that had been visited to that point, [50] [53] and a helix-shaped magnetic tail stretching 10 million kilometers (6 million miles) away from the Sun. [50]

  3. Rotation period (astronomy) - Wikipedia

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

    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 stars (inertial space). The other type of commonly used "rotation period" is the object's synodic rotation period (or solar day), which may differ, by a fraction ...

  4. Orbital period - Wikipedia

    en.wikipedia.org/wiki/Orbital_period

    The Earth's motion does not determine this value for other planets because an Earth observer is not orbited by the moons in question. For example, Deimos's synodic period is 1.2648 days, 0.18% longer than Deimos's sidereal period of 1.2624 d. [citation needed]

  5. Sidereal time - Wikipedia

    en.wikipedia.org/wiki/Sidereal_time

    A mean solar day (what we normally measure as a "day") is the average time between local solar noons ("average" since this varies slightly over a year). Earth makes one rotation around its axis each sidereal day; during that time it moves a short distance (about 1°) along its orbit around the Sun.

  6. Gliese 581d - Wikipedia

    en.wikipedia.org/wiki/Gliese_581d

    These were based on the six-planet and four-planet model for the Gliese 581 system, respectively. Under the four-planet model Gliese 581d would most probably be in a spin-orbit resonance of 2:1, rotating twice for each orbit of its parent star. Therefore, the day on Gliese 581d should approximately be 67 Earth days long. [16] [25]

  7. Mars sol - Wikipedia

    en.wikipedia.org/wiki/Mars_sol

    It is approximately 24 hours, 39 minutes, 35 seconds long. A Martian year is approximately 668.6 sols, equivalent to approximately 687 Earth days [1] or 1.88 Earth years. The sol was adopted in 1976 during the Viking Lander missions and is a measure of time mainly used by NASA when, for example, scheduling the use of a Mars rover. [2] [3]

  8. Transit-timing variation - Wikipedia

    en.wikipedia.org/wiki/Transit-timing_variation

    The transiting planet Kepler-19b shows transit-timing variation with an amplitude of 5 minutes and a period of about 300 days, indicating the presence of a second planet, Kepler-19c, which has a period that is a near-rational multiple of the period of the transiting planet. [8] [9]

  9. List of interplanetary voyages - Wikipedia

    en.wikipedia.org/wiki/List_of_interplanetary_voyages

    (1 yr, 2 mo, 20 d) Vega 1 flew by Halley at a minimum distance of 8,890 km. Vega 2: Venus 21 December 1984 15 June 1985 177 days (5 months, 26 days) Vega 2 flew by Venus. [99] Comet 1P/Halley: 9 March 1986 444 days (1 yr, 2 mo, 17 d) Vega 2 flew by Halley at a minimum distance of 8,890 km. Sakigake: Comet 1P/Halley: 7 January 1985 11 March 1986 ...