Astrophysics (index)

Obliquity

(Axial Tilt)
(angle between an object's rotational and orbital axes)

Obliquity (or Axial Tilt) is the angle between a planet's rotational axis and its orbital axis, or equivalently between its orbital plane and its equatorial plane.

Solar system examples:

  • Sun: 7.25° (against Earth's orbit, i.e., the Ecliptic, compared to the Galactic Plane, it is 67.23°)
  • Mercury: 0° (tidally locked)
  • Venus: 177.36° (rotates retrograde compared to orbit)
  • Earth: 23.4°
  • Moon: 6.68°
  • Mars: 25.19°
  • Jupiter: 3.13°
  • Saturn: 26.73°
  • Uranus: 97.77°
  • Neptune: 28.32°
  • Pluto: 122.53°

Both the Moon and Mercury have an obliquity such that the polar regions receive little sunlight.


(astronomy)
http://en.wikipedia.org/wiki/Axial_tilt

index