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Earth's rotation. Earth's rotation or Earth's spin is the rotation of planet Earth around its own axis, as well as changes in the orientation of the rotation axis in space. Earth rotates eastward, in prograde motion. As viewed from the northern polar star Polaris, Earth turns counterclockwise . The North Pole, also known as the Geographic North ...
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). If the position angle of the body's prime meridian increases with time, the body has a direct (or prograde ) rotation; otherwise the rotation is ...
The North Pole, also known as the Geographic North Pole, Terrestrial North Pole or 90th Parallel North, is the point in the Northern Hemisphere where the Earth's axis of rotation meets its surface. It is called the True North Pole to distinguish from the Magnetic North Pole.
The Earth-centered, Earth-fixed coordinate system (acronym ECEF ), also known as the geocentric coordinate system, is a cartesian spatial reference system that represents locations in the vicinity of the Earth (including its surface, interior, atmosphere, and surrounding outer space) as X, Y, and Z measurements from its center of mass.
Polar motion in arc-seconds as function of time in days (0.1 arcsec ≈ 3 meters). [1] Polar motion of the Earth is the motion of the Earth's rotational axis relative to its crust. [2] : 1 This is measured with respect to a reference frame in which the solid Earth is fixed (a so-called Earth-centered, Earth-fixed or ECEF reference frame).
The azimuth is the angle formed between a reference direction (in this example north) and a line from the observer to a point of interest projected on the same plane as the reference direction orthogonal to the zenith. An azimuth ( / ˈæzəməθ / ⓘ; from Arabic: اَلسُّمُوت, romanized : as-sumūt, lit. 'the directions') [1] is the ...
In astronomy, position angle (usually abbreviated PA) is the convention for measuring angles on the sky. The International Astronomical Union defines it as the angle measured relative to the north celestial pole (NCP), turning positive into the direction of the right ascension. In the standard (non-flipped) images, this is a counter clockwise ...
A geographical pole or geographic pole is either of the two points on Earth where its axis of rotation intersects its surface. [1] The North Pole lies in the Arctic Ocean while the South Pole is in Antarctica. North and South poles are also defined for other planets or satellites in the Solar System, with a North pole being on the same side of ...