Axis of the equator, ecliptic, horizon (or other circle considered with reference to the sphere on which it lies)
the diameter of the sphere which is perpendicular to the plane of the circle. Hutton.
noun the apparent surface of the imaginary sphere on which celestial bodies appear to be projected
firmament; vault of heaven; welkin; empyrean; sphere; heavens.
Circle of the sphere
a circle upon the surface of the sphere, called a great circle when its plane passes through the center of the sphere; in all other cases, a small circle.
Crystalline heavens, ∨ Crystalline spheres
in the Ptolemaic system of astronomy, two transparent spheres imagined to exist between the region of the fixed stars and the primum mobile (or outer circle of the heavens, which by its motion was supposed to carry round all those within it), in order to explain certain movements of the heavently bodies.
Doctrine of the sphere
applications of the principles of spherical trigonometry to the properties and relations of the circles of the sphere, and the problems connected with them, in astronomy and geography, as to the latitudes and longitudes, distance and bearing, of places on the earth, and the right ascension and declination, altitude and azimuth, rising and setting, etc., of the heavenly bodies; spherical geometry.
Great circle of a sphere
a circle the plane of which passes through the center of the sphere.
Harmony of the spheres
. See Music of the spheres, under Music.
Music of the spheres
noun an inaudible music that Pythagoras thought was produced by the celestial
the harmony supposed to be produced by the accordant movement of the celestial spheres.
(Astron. & Geog.), the celestial or terrestrial sphere when its axis is oblique to the horizon of the place; or as it appears to an observer at any point on the earth except the poles and the equator.
(to a line of double curvature), a sphere passing through four consecutive points of the curve.
Parallel circles of a sphere
those circles of the sphere whose planes are parallel to each other.
(Astron. & Geog.), that position of the sphere in which the circles of daily motion are parallel to the horizon, as to an observer at either pole.
noun a sphere of intense political activity
(Astron. & Geol.), a sphere in such a position that the equator cuts the horizon at right angles; in spherical projections, that position of the sphere in which the primitive plane coincides with the plane of the equator.
Sector of a sphere, ∨ Spherical sector
the solid generated by the revolution of the sector of a circle about one of its radii, or, more rarely, about any straight line drawn in the plane of the sector through its vertex.
Segment of a sphere
the part of a sphere cut off by a plane, or included between two parallel planes.
(Biol.), the blastosphere, or morula. See Morula.
sphere of influence
noun the geographical area in which one nation is very influential
thelonious sphere monk
noun United States jazz pianist who was one of the founders of the bebop style (1917-1982)
Monk; Thelonious Monk.