A variation of the Everlasting Cross is the Carolingian Cross, named after the Carolingian dynasty, a Frankish noble family that can be traced back to the seventh century. One member of this family, Pepin the Short, was crowned King of the Franks by the church, who saw this as a useful way to extend their authority over the [...]
Triquetra (IPA: [tɹaɪ'kwεtɹə]) is a word derived from the Latin tri- (“three”) and quetrus (“cornered”). Its original meaning was simply “triangle” and it has been used to refer to various three-cornered shapes. Nowadays, it has come to refer exclusively to a certain more complicated shape formed of three vesicae piscis, sometimes with an added circle in or around it. This widely recognized [...]
The concept of a many-branched tree illustrating the idea that all life on earth is related has been used in science, religion, philosophy, mythology and other areas. A tree of life is variously, a) a mystical concept alluding to the interconnectedness of all life on our planet, b) a metaphor for common descent in the evolutionary sense, and c) a motif in various world theologies, mythologies and philosophies.Various trees of life are [...]
The Engraved Hourglass Nebula (also known as MyCn 18) is a young planetary nebula situated in the southern constellation Musca about 8,000 light-years away from Earth. It was discovered by Annie Jump Cannon and Margaret W. Mayall during their work on an extended Henry Draper Catalogue. At the time [January 18, 1996] it was designated simply as a small faint planetary nebula. Much improved telescopes and imaging techniques [...]
A Mandorla is a Vesica Piscis shaped aureola which surrounds the figures of Christ and the Virgin Mary in traditional Christian art. It is especially used to frame the figure of Christ in Majesty in early medieval and Romanesque art, as well as Byzantine art of the same periods. The term refers to the almond like shape: “mandorla” means almond nut in Italian. In iconsof the Eastern Orthodox Church, the [...]
A compass, magnetic compass or mariner’s compass is a navigational instrument for determining direction relative to the earth’s magnetic poles. It consists of a magnetized pointer (usually marked on the North end) free to align itself with Earth’s magnetic field. The face of the compass generally highlights the cardinal points of north, south, east and west. The compass greatly improved the safety and efficiency [...]
A small circle of a sphere is the circle constructed by a plane crossing the sphere not in its center. Small circles always have smaller diameters than the sphere itself (compare great circle). Small circles cannot be parallel, because parallelism doesn’t exist in spherical geometry. They may look parallel but they are no more parallel than concentric circles on a plane.
The small circle does [...]
A great circle of a sphere is a circle that runs along the surface of that sphere so as to cut it into two equal halves. The great circle therefore has both the same circumference and the same center as the sphere. It is the largest circle that can be drawn on a given sphere.
Great circles serve as the analogue of [...]
