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  2. Mercury (planet) - Wikipedia

    en.wikipedia.org/wiki/Mercury_(planet)

    Mercury is one of four terrestrial planets in the Solar System, which means it is a rocky body like Earth. It is the smallest planet in the Solar System, with an equatorial radius of 2,439.7 kilometres (1,516.0 mi). [4] Mercury is also smaller—albeit more massive—than the largest natural satellites in the Solar System, Ganymede and Titan.

  3. Orbital period - Wikipedia

    en.wikipedia.org/wiki/Orbital_period

    The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy , it usually applies to planets or asteroids orbiting the Sun , moons orbiting planets, exoplanets orbiting other stars , or binary stars .

  4. VSOP model - Wikipedia

    en.wikipedia.org/wiki/VSOP_model

    In VSOP87 especially these long period terms were addressed, resulting in much higher accuracy, although the calculation method itself remained similar. VSOP87 guarantees for Mercury, Venus, the Earth-Moon barycenter and Mars a precision of 1" for 4000 years before and after

  5. Rotation period (astronomy) - Wikipedia

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

    Rotation period with respect to distant stars, the sidereal rotation period (compared to Earth's mean Solar days) Synodic rotation period (mean Solar day) Apparent rotational period viewed from Earth Sun [i] 25.379995 days (Carrington rotation) 35 days (high latitude) 25 d 9 h 7 m 11.6 s 35 d ~28 days (equatorial) [2] Mercury: 58.6462 days [3 ...

  6. Historical models of the Solar System - Wikipedia

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

    The square of the period of the planet (one revolution around the Sun) is proportional to the cube of the average distance from the Sun. [73] In modern notation, = [73] 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.

  7. A Complete Guide to Every Mercury Retrograde Happening ... - AOL

    www.aol.com/lifestyle/complete-guide-every...

    Mercury retrograde refers to the period of time when Mercury moves slower than the Earth around the sun – causing it to appear to spin backward in the night sky. Retrograde motion is an apparent ...

  8. Apsidal precession - Wikipedia

    en.wikipedia.org/wiki/Apsidal_precession

    In the case of Mercury, half of the greater axis is about 5.79 × 10 10 m, the eccentricity of its orbit is 0.206 and the period of revolution 87.97 days or 7.6 × 10 6 s. From these and the speed of light (which is ~ 3 × 10 8 m/s ), it can be calculated that the apsidal precession during one period of revolution is ε = 5.028 × 10 −7 ...

  9. Orbital resonance - Wikipedia

    en.wikipedia.org/wiki/Orbital_resonance

    An undetected planet with a 13.0-day period would create a 3:2 resonance chain. [66] Kepler-88 has a pair of inner planets close to a 1:2 resonance (period ratio of 2.0396), with a mass ratio of ~22.5, producing very large transit timing variations of ~0.5 days for the innermost planet. There is a yet more massive outer planet in a ~1400 day orbit.