In archaeology, a spheroid is a piece of rock that has been shaped into a spherical shape. Spheroids have been found at sites from as long ago as 1.8 million years. It is not known what their purpose was, but it has been speculated that they were used as projectiles in hunting. At one site (Ubeidiya prehistoric site near the Sea of Galilee, 1.4 million years old) around 600 baseball-sized spheroids of limestone, basalt, and flint have been found, and it has been demonstrated that they were not simply hand axes that became spherical through use, but were deliberately made as spheres. [1] [2]
A ball is a round object with several uses. It is used in ball games, where the play of the game follows the state of the ball as it is hit, kicked or thrown by players. Balls can also be used for simpler activities, such as catch or juggling. Balls made from hard-wearing materials are used in engineering applications to provide very low friction bearings, known as ball bearings. Black-powder weapons use stone and metal balls as projectiles.
A sphere is a geometrical object that is a three-dimensional analogue to a two-dimensional circle. Formally, a sphere is the set of points that are all at the same distance r from a given point in three-dimensional space. That given point is the centre of the sphere, and r is the sphere's radius. The earliest known mentions of spheres appear in the work of the ancient Greek mathematicians.
A water tower is an elevated structure supporting a water tank constructed at a height sufficient to pressurize a distribution system for potable water, and to provide emergency storage for fire protection. Water towers often operate in conjunction with underground or surface service reservoirs, which store treated water close to where it will be used. Other types of water towers may only store raw (non-potable) water for fire protection or industrial purposes, and may not necessarily be connected to a public water supply.
A spheroid, also known as an ellipsoid of revolution or rotational ellipsoid, is a quadric surface obtained by rotating an ellipse about one of its principal axes; in other words, an ellipsoid with two equal semi-diameters. A spheroid has circular symmetry.
A football is a ball inflated with air that is used to play one of the various sports known as football. In these games, with some exceptions, goals or points are scored only when the ball enters one of two designated goal-scoring areas; football games involve the two teams each trying to move the ball in opposite directions along the field of play.
Earth radius is the distance from the center of Earth to a point on or near its surface. Approximating the figure of Earth by an Earth spheroid, the radius ranges from a maximum of nearly 6,378 km (3,963 mi) to a minimum of nearly 6,357 km (3,950 mi).
Spherical Earth or Earth's curvature refers to the approximation of the figure of the Earth as a sphere. The earliest documented mention of the concept dates from around the 5th century BC, when it appears in the writings of Greek philosophers. In the 3rd century BC, Hellenistic astronomy established the roughly spherical shape of Earth as a physical fact and calculated the Earth's circumference. This knowledge was gradually adopted throughout the Old World during Late Antiquity and the Middle Ages. A practical demonstration of Earth's sphericity was achieved by Ferdinand Magellan and Juan Sebastián Elcano's circumnavigation (1519–1522).
In geodesy, the figure of the Earth is the size and shape used to model planet Earth. The kind of figure depends on application, including the precision needed for the model. A spherical Earth is a well-known historical approximation that is satisfactory for geography, astronomy and many other purposes. Several models with greater accuracy have been developed so that coordinate systems can serve the precise needs of navigation, surveying, cadastre, land use, and various other concerns.
A globe is a spherical model of Earth, of some other celestial body, or of the celestial sphere. Globes serve purposes similar to maps, but unlike maps, they do not distort the surface that they portray except to scale it down. A model globe of Earth is called a terrestrial globe. A model globe of the celestial sphere is called a celestial globe.
The great-circle distance, orthodromic distance, or spherical distance is the distance along a great circle.
The stone spheres of Costa Rica are an assortment of over 300 petrospheres in Costa Rica, on the Diquís Delta and on Isla del Caño. Locally, they are also known as bolas de piedra. The spheres are commonly attributed to the extinct Diquís culture, and they are sometimes referred to as the Diquís Spheres. They are the best-known stone sculptures of the Isthmo-Colombian area.
Klerksdorp spheres are small objects, often spherical to disc-shaped, that have been collected by miners and rockhounds from 3-billion-year-old pyrophyllite deposits mined by Wonderstone Ltd., near Ottosdal, South Africa. They have been cited by pseudoscientists and reporters in books, popular articles, and many web pages as inexplicable out-of-place artifacts that could only have been manufactured by intelligent beings. Geologists who have studied these objects have concluded that the objects are not manufactured, but are rather the result of natural processes.
A stone ball is a spherical man-made stone object.
The prehistory of the Levant includes the various cultural changes that occurred, as revealed by archaeological evidence, prior to recorded traditions in the area of the Levant. Archaeological evidence suggests that Homo sapiens and other hominid species originated in Africa and that one of the routes taken to colonize Eurasia was through the Sinai Peninsula desert and the Levant, which means that this is one of the most important and most occupied locations in the history of the Earth. Not only have many cultures and traditions of humans lived here, but also many species of the genus Homo. In addition, this region is one of the centers for the development of agriculture.
In geometry, a spherical polyhedron or spherical tiling is a tiling of the sphere in which the surface is divided or partitioned by great arcs into bounded regions called spherical polygons. Much of the theory of symmetrical polyhedra is most conveniently derived in this way.
In archaeology, a stone ball or petrosphere is the name for any spherical man-made object of any size that is composed of stone. These mainly prehistoric artifacts may have been created or selected, but altered in some way to perform their specific function, including carving and painting.
A great ellipse is an ellipse passing through two points on a spheroid and having the same center as that of the spheroid. Equivalently, it is an ellipse on the surface of a spheroid and centered on the origin, or the curve formed by intersecting the spheroid by a plane through its center. For points that are separated by less than about a quarter of the circumference of the earth, about , the length of the great ellipse connecting the points is close to the geodesic distance. The great ellipse therefore is sometimes proposed as a suitable route for marine navigation. The great ellipse is special case of an earth section path.
'Ubeidiya, some 3 km south of the Sea of Galilee, in the Jordan Rift Valley, Israel, is an archaeological site of the early Pleistocene, c. 1.5 million years ago, preserving traces of one of the earliest migrations of Homo erectus out of Africa, with only the site of Dmanisi in Georgia being older. The site yielded hand axes of the Acheulean type, but very few human remains. The animal remains include a hippopotamus' femur bone, and an immensely large pair of horns belonging to a species of extinct bovid.
The equator is a circle of latitude that divides a spheroid, such as Earth, into the northern and southern hemispheres. On Earth, it is an imaginary line located at 0 degrees latitude, about 40,075 km (24,901 mi) in circumference, halfway between the North and South poles. The term can also be used for any other celestial body that is roughly spherical.
Microspherulites are microscopic spherical particles with diameter less than two mm, usually in the 100 micrometre range, mainly consisting of mineral material. Only bodies created by natural physico-chemical processes, with no contribution of either biological or human activity, are considered to be microspherulites. Generally speaking, the common feature (sphericity) indicates that each sphere represents an internal equilibrium of forces within a fluid medium.