cave (redirected from caved)

cave, a cavity in the earth's surface usually large enough for a person to enter. Caves may be formed by the chemical and mechanical action of a stream upon soluble or soft rock, of rainwater seeping through soluble rock to the groundwater level, or of waves dashed against a rocky shore. Volcanic action (accompanied by the formation of gas pockets in lava or the melting of ice under lava) and earthquakes or other earth movements are also sources of cave formation. Limestone regions almost invariably have caves; some of these are notable for their stalactite and stalagmite formations or for their magnitude and beauty.

The preserved remains of prehistoric humans and animals and indications of early human culture have been discovered in some caves. Caves have served as burial grounds and shelter since prehistoric times. One such cave is Alabama's Russell Cave, where human evidence dates back 9,000 years. Speleology, the scientific study of caves and their plant and animal life, contributes to knowledge of biological adaptation and evolution. Some cave animals lack sight, and both plants and animals living where light is excluded show loss of pigment. Deep cave ecosystems, lacking the sunlight necessary for photosynthesis, depend on bacteria that use chemosynthesis to create energy.

Among famous caves in the United States are Carlsbad Caverns National Park (N.Mex.), Mammoth Cave National Park (Ky.), Wind Cave National Park (Black Hills, S.Dak.), Luray Caverns (Va.), and Wyandotte Cave (Ind.). In Europe there are celebrated caves in Belgium, Dalmatia, Gibraltar, Capri, Sicily, Postojna, and England (Kent's Cavern and Kirkdale). The caves of the Pyrenees and the Dordogne are famed for their prehistoric paintings (see Paleolithic art), and those of Ajanta, India, and Dunhuang, China, for their Buddhist frescoes. Among the deepest known caves are Krubera in the nation of Georgia, which extends more than 6,500 ft (2,000 m) below the surface, and Lamprechtsofen in Austria.

Bibliography

See C. E. Mohr and T. L. Poulson, The Life of the Cave (1966); D. R. McClurg, The Amateur's Guide to Caves and Caving (1973).

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cave

Naturally formed underground cavity. A cave often consists of a number of underground chambers, constituting a series of caverns. An assemblage of such caverns interconnected by smaller passageways makes up a cave system. Primary caves, such as lava tubes and coral caves, develop during the time when the host matrix is solidifying or being deposited. Secondary caves, such as marine grottoes, originate after the host matrix has been deposited or consolidated. Most caves are of the latter type, including solution caves formed by the chemical dissolution of a soluble host rock that has been weakened by fracturing and mechanical erosion; Mammoth Cave and Carlsbad Caverns are examples of solution caves.

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(Computer Automatic Virtual Environment) A virtual reality system that uses projectors to display images on three or four walls and the floor. Special glasses make everything appear as 3D images and also track the path of the user's vision.

CAVE was the first virtual reality system to let multiple users participate in the experience simultaneously. Known as a "spatially immersive display," it was developed by the Electronic Visualization Laboratory at the University of Illinois in the early 1990s. See head mounted display and virtual reality.

Simulating New Architecture

CAVE is used to simulate a newly designed train station to evaluate its functionality. (Image courtesy of Fakespace Systems Inc.)

Training People

This CAVE system teaches people how to operate a Caterpillar bulldozer. The steering wheel on the left meets the real steering wheel in virtual space, appearing to the man as the actual wheel he is turning. (Image courtesy of Fakespace Systems Inc.)