great circle

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great circle

Geometry a circular section of a sphere that has a radius equal to that of the sphere

great circle

The circular intersection on the surface of a sphere of any plane passing through the center of the sphere. A sphere and its great circles are thus concentric and of equal radius. Compare small circle.

Great Circle

(religion, spiritualism, and occult)

A great circle is any circle drawn on a sphere, the plane of which also passes through the inside of the sphere. Great circles are the basis of various systems for locating terrestrial and celestial bodies in terms of sets of coordinates expressed in degrees of a circle. Longitude and latitude are the most familiar of these coordinates. Astrology utilizes several systems of celestial coordinates. Parallel to the manner in which terrestrial coordinates are great circles drawn on the surface of Earth, celestial coordinates are great circles drawn on the inside of the celestial sphere. The ecliptic, the celestial equator, and the prime vertical are examples of some of the great circles used in astrology.

great circle

[′grāt ¦sər·kəl]
(geodesy)
A circle, or near circle, described on the earth's surface by a plane passing through the center of the earth.
(mathematics)
The circle on the two-sphere produced by a plane passing through the center of the sphere.

great circle

great circle
Two great circle in a sphere.
A circle on the surface of the sphere (earth) whose center and radii are those of the sphere itself. Only one great circle may be drawn through two places that are not diametrically opposite on the surface of a sphere. The shortest distance between any two points on the surface is the smaller arc of the great circle joining them. An aircraft following a great circle (other than directly true north or south) will have to alter course constantly. The intersection of a sphere and a plane that does not pass through its center is called a small circle.
References in periodicals archive ?
Aircraft routes approximate to great circles because an arc of a great circle is the shortest distance between two points on the sphere.
Any two great circles will intersect in two points that are antipodes of each other.
That is, any two great circles on the sphere meet at a pair of antipodal points.
To understand these limits, the intersection I of a spherical lune defined by two great circles with angle [omega], and, perpendicular to that lune, an infinitely thin spherical segment defined by two parallel small circles with angular distance t are constructed (Figure 13a).
Until this complete account of the excavations at Barnhouse, however, no researcher has succeeded in connecting the two differing facets of Orcadian prehistory: the monumental represented by the tombs and great circles the Ring of Brodgar and the Stones of Stenness; and the domestic as represented by Skara Brai, Rinyo, and Knap of Howar.
2] are the measurable circumferences of great circles at aphelion and at perihelion.
The years provided further glimpses: Sanders at the twenty-fifth anniversary of On the Road's publication in Boulder, a ten-day celebration where not only attendees imbibed ritualistically but Trungpa Rinpoche swigged sake from the stage as he addressed the enclave, moving his arms in great circles symbolizing OM, universal peace.
The meridians of longitude loop from the North Pole to the South and back again in great circles of the same size, so they all converge at the ends of the Earth.
After consideration of various arrangements of framing, a treble intersection system of ribs, all of which lay on great circles of the dome for the whole or part of their length, were adopted'.
Scanning the heavens in great circles that pass through the north and south ecliptic poles, the German-built X-ray telescope imaged much fainter objects and achieved an angular resolution three times greater than the orbiting Einstein Observatory, which conducted a smaller X-ray imaging survey in 1979.
On the sphere, edges are minor arcs of great circles (like the line segments in the plane, these arcs are also geodesics).
An example of the latter is an evolution along a great circle on a sphere for a two-level system which we will encounter in the forthcoming discussion.