Columbia Encyclopedia

Search results

500 results found

synodic period

(Encyclopedia)synodic period sĭnŏdˈĭk [key], in astronomy, length of time during which a body in the solar system makes one orbit of the sun relative to the earth, i.e., returns to the same elongation. Because ...

atmosphere

(Encyclopedia)CE5 Atmosphere atmosphere [Gr.,=sphere of air], the mixture of gases surrounding a celestial body with sufficient gravity to maintain it. Although some details about the atmospheres of other plane...

seasons

(Encyclopedia)CE5 The seasons are caused by the tilt of the earth's axis to the plane of its orbit about the sun. The Northern Hemisphere is tilted toward the sun in the summer and receives more direct rays than...

space medicine

(Encyclopedia)space medicine, study of the medical and biological effects of space travel on living organisms. The principal aim is to discover how well and for how long humans can withstand the extreme conditions ...

Woden

(Encyclopedia)Woden ōˈdĭn [key], in Germanic religion and mythology, the supreme god. His cult, although widespread among the Germanic tribes, was sometimes subordinated to that of his son Thor. With his brother...

Urgench , ancient city, present-day Turkmenistan

(Encyclopedia)Urgench o͝orgyĕnchˈ [key], ancient city of central Asia, on the site of present-day Kunya-Urgench (Köhne Ürgenç), in Turkmenistan. It lies c.85 mi (140 km) NW of modern Urganch, Uzbekistan. A ma...

latitude

(Encyclopedia)latitude, angular distance of any point on the surface of the earth north or south of the equator. The equator is latitude 0°, and the North Pole and South Pole are latitudes 90°N and 90°S, respect...

blockhouse

(Encyclopedia)blockhouse, small fortification, usually temporary, serving as a post for a small garrison. Blockhouses seem to have come into use in the 15th cent. to prevent access to a strategically important obje...

moon

(Encyclopedia)CE5 The moon: Near side CE5 The moon: Far side moon, natural satellite of a planet (see satellite, natural) or dwarf planet, in particular, the single natural satellite of the earth. It is no...

continental drift

(Encyclopedia)CE5 Continental drift (arrows indicate the directions of motion of the landmasses) A. Proposed reconstruction of the supercontinent Pangaea indicating the major present landmasses B. Proposed recon...