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The International Astronomical Union (IAU) defines the north pole of a planet or any of its satellites in the Solar System as the planetary pole that is in the same celestial hemisphere, relative to the invariable plane of the Solar System, as Earth's north pole. [1] This definition is independent of the object's direction of rotation about its ...
All eight planets in the Solar System orbit the Sun in the direction of the Sun's rotation, which is counterclockwise when viewed from above the Sun's north pole. Six of the planets also rotate about their axis in this same direction. The exceptions – the planets with retrograde rotation – are Venus and Uranus.
Earth's rotation axis moves with respect to the fixed stars (inertial space); the components of this motion are precession and nutation. It also moves with respect to Earth's crust; this is called polar motion. Precession is a rotation of Earth's rotation axis, caused primarily by external torques from the gravity of the Sun, Moon and other bodies.
To take into account such movement, celestial pole definitions come with an epoch to specify the date of the rotation axis; J2000.0 is the current standard. An analogous concept applies to other planets: a planet's celestial poles are the points in the sky where the projection of the planet's axis of rotation intersects the celestial sphere.
The north pole is that pole of rotation that lies on the north side of the invariable plane of the Solar System (near the ecliptic). The location of the prime meridian as well as the position of the body's north pole on the celestial sphere may vary with time due to precession of the axis of rotation of the planet (or satellite).
The rotation axis of the Earth describes, over a period of 25,700 years, a small blue circle among the stars near the top of the diagram, centered on the ecliptic north pole (the blue letter E) and with an angular radius of about 23.4°, an angle known as the obliquity of the ecliptic. The direction of precession is opposite to the daily ...
The relative direction of diurnal motion in the Northern Celestial Hemisphere are as follows: Facing north, below Polaris: rightward, or eastward; Facing north, above Polaris: leftward, or westward; Facing south: rightward, or westward; Thus, northern circumpolar stars move counterclockwise around Polaris, the north pole star.
The north orbital poles of the Solar System major planets all lie within Draco. [1] The central yellow dot represents the Sun's rotation axis north pole. [citation needed] Jupiter's north orbital pole is colored orange, Mercury's pale blue, Venus's green, Earth's blue, Mars's red, Saturn's magenta, Uranus's grey, and Neptune's lavender.