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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. Sun-synchronous orbit - Wikipedia

    en.wikipedia.org/wiki/Sun-synchronous_orbit

    i is the inclination of the orbit to the equator. An orbit will be Sun-synchronous when the precession rate ρ = ⁠ d Ω d t⁠ equals the mean motion of the Earth about the Sun nE, which is 360° per sidereal year (1.990 968 71 × 10−7 rad /s), so we must set nE = ⁠ Δ ΩE TE⁠ = ρ = ⁠ Δ Ω T⁠ , where TE is the earth orbital period ...

  4. Mars - Wikipedia

    en.wikipedia.org/wiki/Mars

    Mars's average distance from the Sun is roughly 230 million km (143 million mi), and its orbital period is 687 (Earth) days. The solar day (or sol) on Mars is only slightly longer than an Earth day: 24 hours, 39 minutes, and 35.244 seconds. [185] A Martian year is equal to 1.8809 Earth years, or 1 year, 320 days, and 18.2 hours. [2]

  5. Astronomical unit - Wikipedia

    en.wikipedia.org/wiki/Astronomical_unit

    The astronomical unit (symbol: au[1][2][3][4] or AU) is a unit of length defined to be exactly equal to 149,597,870,700 m. [5] Historically, the astronomical unit was conceived as the average Earth-Sun distance (the average of Earth's aphelion and perihelion), before its modern redefinition in 2012. The astronomical unit is used primarily for ...

  6. Interstellar travel - Wikipedia

    en.wikipedia.org/wiki/Interstellar_travel

    Interstellar travel is the hypothetical travel of spacecraft between star systems. Due to the vast distances between the Solar System and nearby stars, interstellar travel is not practicable with current propulsion technologies. To travel between stars within a reasonable amount of time (decades or centuries), an interstellar spacecraft must ...

  7. Earth's orbit - Wikipedia

    en.wikipedia.org/wiki/Earth's_orbit

    Earth orbit (yellow) compared to a circle (gray) Earth orbits the Sun at an average distance of 149.60 million km (92.96 million mi), or 8.317 light-minutes, [1] in a counterclockwise direction as viewed from above the Northern Hemisphere. One complete orbit takes 365.256 days (1 sidereal year), during which time Earth has traveled 940 million ...

  8. Mars may be around 140 million miles away from Earth, but the red planet is influencing our oceans, according to new research. Mars could be driving ‘giant whirlpools’ in the Earth’s deep ...

  9. Elongation (astronomy) - Wikipedia

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

    Elongation (astronomy) In astronomy, angular separation between the Sun and a planet, with the Earth as a reference point. 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 ...