Columbia Encyclopedia

Search results

500 results found

Pentastomida

(Encyclopedia)Pentastomida pĕnˈtəstōˌmə [key], tongue worms, small phylum of fewer than 100 species of parasites living in the upper respiratory passages of reptiles, and occasionally of birds and mammals. Th...

Hubble's law

(Encyclopedia)Hubble's law, in astronomy, statement that the distances between galaxies (see galaxy) or clusters of galaxies are continuously increasing and that therefore the universe is expanding. Hubble's law ...

magnetism

(Encyclopedia)CE5 Lines of induction around a single bar magnet and between opposite poles of different magnets magnetism, force of attraction or repulsion between various substances, especially those made of i...

galaxy

(Encyclopedia)CE5 Hubble classification of galaxies: Elliptical galaxies (E) are classified according to the degree of flattening of the ellipse. Spiral galaxies (S) and barred spiral galaxies (SB) are classifie...

planetarium

(Encyclopedia)planetarium, optical device used to project a representation of the heavens onto a domed ceiling; the term also designates the building that houses such a device. A modern planetarium consists of as m...

Cartesian coordinates

(Encyclopedia)CE5 Cartesian coordinates Cartesian coordinates kärtēˈzhən [key] [for René Descartes], system for representing the relative positions of points in a plane or in space. In a plane, the point P...

air, law of the

(Encyclopedia)air, law of the, in the broadest sense, all law connected with the use of the air, including radio and satellite transmissions; more commonly, it refers to laws concerning civil aviation. The developm...

sound

(Encyclopedia)CE5 Sound waves: An air pressure wave radiating outward from a loudspeaker is perceived as sound. sound, any disturbance that travels through an elastic medium such as air, ground, or water to be ...

mesoderm

(Encyclopedia)mesoderm, in biology, middle layer of tissue formed in the gastrula stage of the developing embryo. At the end of the blastula stage, cells of the embryo are arranged in the form of a hollow ball. Con...

molecular orbital theory

(Encyclopedia)molecular orbital theory, detailed explanation of how electrons are distributed in stable molecules. In the simpler valence theory of the chemical bond, each atom in a molecule is assumed to retain it...