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(110–210 Earth radii) 6.36×10 6 –1.27×10 7: The space dominated by Earth's magnetic field and its magnetotail, shaped by the solar wind. [17] Earth's orbit: 299.2 million km [b] 2 AU [c] 2.99×10 8: The average diameter of the orbit of the Earth relative to the Sun. Encompasses the Sun, Mercury and Venus. [18] Inner Solar System ~6.54 AU ...
In astronomy, coordinate systems are used for specifying positions of celestial objects (satellites, planets, stars, galaxies, etc.) relative to a given reference frame, based on physical reference points available to a situated observer (e.g. the true horizon and north to an observer on Earth's surface). [1] Coordinate systems in astronomy can ...
The Earth's orbit plane is called the ecliptic, and it does not coincide with the Earth's equatorial plane. The angle between the Earth's equatorial plane and the ecliptic, ε, is called the obliquity of the ecliptic and ε ≈ 23.4°. An equinox occurs when the earth is at a position in its orbit such that a vector from the earth toward
The coordinates of objects on the sky are listed using the equatorial coordinate system, which is based on the projection of Earth's equator onto the celestial sphere. The position of an object in this system is given in terms of right ascension (α) and declination (δ).
The barycentric celestial reference system (BCRS) is a coordinate system used in astrometry to specify the location and motions of astronomical objects. It was created in 2000 by the International Astronomical Union (IAU) to be the global standard reference system for objects located outside the gravitational vicinity of Earth: [1] planets, moons, and other Solar System bodies, stars and other ...
The coordinates are given relative to Earth's celestial equator and the vernal equinox as they existed at J2000 (2000 January 1 12:00:00 TT) which is a plane fixed in inertial space now called the International Celestial Reference Frame (ICRF). Many poles precess or otherwise move relative to the ICRF, so their coordinates will change.
As of 1 January 2000, the positions of the ecliptic poles expressed in equatorial coordinates, as a consequence of Earth's axial tilt, are the following: North: right ascension 18 h 0 m 0.0 s (exact), declination +66° 33′ 38.55″ South: right ascension 6 h 0 m 0.0 s (exact), declination −66° 33′ 38.55″
One can intuitively use rectangular coordinates in the plane for one's current location, in which case the x-axis will point to the local north. More formally, such coordinates can be obtained from 3D coordinates using the artifice of a map projection. It is impossible to map the curved surface of Earth onto a flat map surface without deformation.