radius vector


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radius vector

(vek -ter) The line, of length r , joining a point on a curve to a reference point, such as the origin in spherical and cylindrical coordinate systems. In planetary motion the radius vector is the line between the position of a planet and the focus of its orbit, i.e. the Sun's position. See also Kepler's laws.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Radius Vector

 

The radius vector of an arbitrary point in space is the vector drawn to the point from some fixed point, which is called the pole. If the origin of a rectangular Cartesian coordinate system is selected as the pole, then the projections of the radius vector of a point M on the coordinate axes coincide with the coordinates of M.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

radius vector

[′rād·ē·əs ‚vek·tər]
(astronomy)
A line joining the center of an orbiting body with the focus of its orbit located near its primary.
(mathematics)
The coordinate r in a polar coordinate system, which gives the distance of a point from the origin.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
In the general case of a multicomponent material, an indicator function [[lambda].sub.C]([??]) takes the value 1 if the radius vector is in component C and is equal to 0 in all other cases.
The estimation of the spatial position of the radius vector shows the balance of system that represent the level of sustainable development.
with [epsilon] the mean obliquity of the ecliptic as defined in [6]; [r.sup.e.sub.S] is radius vector of Sunmass center in Ecliptic Earth Centered Inertial Frame of J2000.0 defined as
In fact, for any method of compensation where a probe radius vector is added to the coordinates of the probe center, the apparent point of contact cannot lie within the physical material and consequently compensation errors will always result in underestimating an internal diameter or overestimating an external diameter.
Note that in this paper the prototype shape is described by the thickness of the body measured orthogonally to the symmetry axis and not by the radius vector function as in Streit (1997; 2000; 2003; 2005; 2006).
The efficient technique of the approximation of star contours of sources by a radius vector which is set by the truncated trigonometric series has been used for cylindrical bodies with polygonal sections (Bulach & Mikheeva 1993)
(He makes the analogy with light, whose illuminating power decreases with distance.) First assuming that the orbits are eccentric circles (as did Ptolemy), he formulated his second law (chronologically the first) The radius vector of the orbit sweeps out equal areas in equal times.
The position of the earth at any time is specified by the angle [alpha] of the radius vector from sun to earth, which we will measure counterclockwise from the Spring equinox, with -180[degrees] < [alpha] [less than or equal to] 180[degrees] as in Figure 1.
Here Kepler set forth his first two laws of celestial motion: the planetary orbit is an ellipse with the sun as one of the loci; and the radius vector drawn from the sun describes equal areas in equal times.