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  2. Earth's orbit - Wikipedia

    en.wikipedia.org/wiki/Earth's_orbit

    Ignoring the influence of other Solar System bodies, Earth's orbit, also called Earth's revolution, is an ellipse with the EarthSun barycenter as one focus with a current eccentricity of 0.0167. Since this value is close to zero, the center of the orbit is relatively close to the center of the Sun (relative to the size of the orbit).

  3. Galactic year - Wikipedia

    en.wikipedia.org/wiki/Galactic_year

    The galactic year, also known as a cosmic year, is the duration of time required for the Sun to orbit once around the center of the Milky Way Galaxy. [1] One galactic year is approximately 225 million Earth years. [2]

  4. Axial precession - Wikipedia

    en.wikipedia.org/wiki/Axial_precession

    and 1/2 accounts for the average of the sine squared waveform, () accounts for the average distance cubed of the Sun or Moon from Earth over the entire elliptical orbit, [34] and ε (the angle between the equatorial plane and the ecliptic plane) is the maximum value of δ for the Sun and the average maximum value for the Moon over an entire 18. ...

  5. Precession - Wikipedia

    en.wikipedia.org/wiki/Precession

    As the Earth travels around the Sun, its elliptical orbit rotates gradually over time. The eccentricity of its ellipse and the precession rate of its orbit are exaggerated for visualization. Most orbits in the Solar System have a much smaller eccentricity and precess at a much slower rate, making them nearly circular and nearly stationary.

  6. Ecliptic - Wikipedia

    en.wikipedia.org/wiki/Ecliptic

    The ecliptic or ecliptic plane is the orbital plane of Earth around the Sun. [1] [2] [a] From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic against the background of stars. [3]

  7. Sun - Wikipedia

    en.wikipedia.org/wiki/Sun

    According to a 2008 paper, Earth's orbit will have initially expanded to at most 1.5 AU (220 million km; 140 million mi) due to the Sun's loss of mass. However, Earth's orbit will then start shrinking due to tidal forces (and, eventually, drag from the lower chromosphere) so that it is engulfed by the Sun during the tip of the red-giant branch ...

  8. Earth's rotation - Wikipedia

    en.wikipedia.org/wiki/Earth's_rotation

    Earth's movement along its nearly circular orbit while it is rotating once around its axis requires that Earth rotate slightly more than once relative to the fixed stars before the mean Sun can pass overhead again, even though it rotates only once (360°) relative to the mean Sun. [n 5] Multiplying the value in rad/s by Earth's equatorial ...

  9. Sun-synchronous orbit - Wikipedia

    en.wikipedia.org/wiki/Sun-synchronous_orbit

    An orbit will be Sun-synchronous when the precession rate ρ = ⁠ dΩ / dt ⁠ equals the mean motion of the Earth about the Sun n E, which is 360° per sidereal year (1.990 968 71 × 10 −7 rad/s), so we must set n E = ⁠ ΔΩ E / T E ⁠ = ρ = ⁠ ΔΩ / T ⁠, where T E is the earth orbital period while T is the period of the spacecraft ...