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  2. Orbit of Mars - Wikipedia

    en.wikipedia.org/wiki/Orbit_of_Mars

    Extra-close oppositions of Mars happen every 15 to 17 years, when we pass between Mars and the Sun around the time of its perihelion (closest point to the Sun in orbit). The minimum distance between Earth and Mars has been declining over the years, and in 2003 the minimum distance was 55.76 million km, nearer than any such encounter in almost ...

  3. Astronomical unit - Wikipedia

    en.wikipedia.org/wiki/Astronomical_unit

    This is because the distance between Earth and the Sun is not fixed (it varies between 0.983 289 8912 and 1.016 710 3335 au) and, when Earth is closer to the Sun , the Sun's gravitational field is stronger and Earth is moving faster along its orbital path. As the metre is defined in terms of the second and the speed of light is constant for all ...

  4. Transit of Earth from Mars - Wikipedia

    en.wikipedia.org/wiki/Transit_of_Earth_from_Mars

    Earth and Moon transiting the Sun in 2084, as seen from Mars. Image created using SpaceEngine Earth and Moon from Mars, as photographed by the Mars Global Surveyor. A transit of Earth across the Sun as seen from Mars takes place when the planet Earth passes directly between the Sun and Mars, obscuring a small part of the Sun's disc for an observer on Mars.

  5. Timeline of Solar System astronomy - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_Solar_System...

    1672 – Jean Richer and Cassini measure the Earth-Sun distance, the astronomical unit, to be about 138,370,000 km. [97] 1675 – Ole Rømer uses the orbital mechanics of Jupiter's moons to estimate that the speed of light is about 227,000 km/s. [98]

  6. Mars - Wikipedia

    en.wikipedia.org/wiki/Mars

    Mars has its closest approach to Earth in a synodic period of 779.94 days. It should not be confused with Mars conjunction, where the Earth and Mars are at opposite sides of the Solar System and form a straight line crossing the Sun. The average time between the successive oppositions of Mars, its synodic period, is 780 days; but the number of ...

  7. Jet Propulsion Laboratory Development Ephemeris - Wikipedia

    en.wikipedia.org/wiki/Jet_Propulsion_Laboratory...

    Positions and velocities of the Sun, Earth, Moon, and planets, along with the orientation of the Moon, are stored as Chebyshev polynomial coefficients fit in 32 day-long segments. [10] The ephemerides are now available via World Wide Web and FTP [ 13 ] as data files containing the Chebyshev coefficients, along with source code to recover ...

  8. Elongation (astronomy) - Wikipedia

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

    This diagram shows various possible elongations (ε), each of which is the angular distance between a planet and the Sun from Earth's perspective. In astronomy, a planet's elongation is the angular separation between the Sun and the planet, with Earth as the reference point. [1] The greatest elongation is the maximum angular separation.

  9. Titius–Bode law - Wikipedia

    en.wikipedia.org/wiki/Titius–Bode_law

    This latter point seems in particular to follow from the astonishing relation which the known six planets observe in their distances from the Sun. Let the distance from the Sun to Saturn be taken as 100, then Mercury is separated by 4 such parts from the Sun. Venus is 4+3=7. The Earth 4+6=10. Mars 4+12=16. Now comes a gap in this so orderly ...