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  2. Orbit of Mars - Wikipedia

    en.wikipedia.org/wiki/Orbit_of_Mars

    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 60,000 years (57,617 BC). The record minimum distance between Earth and Mars in 2729 will stand at 55.65 million km.

  3. Geostationary orbit - Wikipedia

    en.wikipedia.org/wiki/Geostationary_orbit

    where F g is the gravitational force acting between two objects, M E is the mass of the Earth, 5.9736 × 10 24 kg, m s is the mass of the satellite, r is the distance between the centers of their masses, and G is the gravitational constant, (6.674 28 ± 0.000 67) × 10 −11 m 3 kg −1 s −2.

  4. Astronomical unit - Wikipedia

    en.wikipedia.org/wiki/Astronomical_unit

    Average distance from Earth (which the Apollo missions took about 3 days to travel) — Solar radius: 0.005 — Radius of the Sun (695 500 km, 432 450 mi, a hundred times the radius of Earth or ten times the average radius of Jupiter) — Light-minute: 0.12 — Distance light travels in one minute — Mercury: 0.39 — Average distance from the ...

  5. Cosmic distance ladder - Wikipedia

    en.wikipedia.org/wiki/Cosmic_distance_ladder

    Radar is used to measure the distance between the orbits of the Earth and of a second body. From that measurement and the ratio of the two orbit sizes, the size of Earth's orbit is calculated. The Earth's orbit is known with an absolute precision of a few meters and a relative precision of a few parts in 100 billion (1 × 10 −11).

  6. Kármán line - Wikipedia

    en.wikipedia.org/wiki/Kármán_line

    While the Kármán line is defined for Earth only, several scientists have estimated the corresponding figures for Mars and Venus. Isidoro Martínez arrived at 80 km (50 miles) and 250 km (160 miles) high, respectively, [31] while Nicolas Bérend arrived at 113 km (70 miles) and 303 km (188 miles). [32]

  7. Minimum orbit intersection distance - Wikipedia

    en.wikipedia.org/wiki/Minimum_orbit_intersection...

    Minimum orbit intersection distance (MOID) is a measure used in astronomy to assess potential close approaches and collision risks between astronomical objects. [1] [2] It is defined as the distance between the closest points of the osculating orbits of two bodies. Of greatest interest is the risk of a collision with Earth.

  8. Areostationary orbit - Wikipedia

    en.wikipedia.org/wiki/Areostationary_orbit

    Substituting the mass of Mars for M and the Martian sidereal day for T and solving for the semimajor axis yields a synchronous orbit radius of 20,428 km (12,693 mi) above the surface of the Mars equator. [3] [4] [5] Subtracting Mars's radius gives an orbital altitude of 17,032 km (10,583 mi). Two stable longitudes exist - 17.92°W and 167.83°E.

  9. List of the most distant astronomical objects - Wikipedia

    en.wikipedia.org/wiki/List_of_the_most_distant...

    It had been determined that the stars were much farther away than the planets. Mars: Planet of the Solar System 1609 − 1619 2.6 AU when Mars is diametrically opposed to Earth Kepler correctly characterized Mars and Earth's orbits in the publication Astronomia nova. It had been conjectured that the fixed stars were much farther away than the ...