Columbia Encyclopedia

Search results

500 results found

Sacrobosco, Johannes de

(Encyclopedia)Sacrobosco, Johannes de yōhänˈəs də săkrōbŏsˈkō [key], or John of Hollywood, c.1200–1256, English mathematician and astronomer. He wrote several widely read and influential books: Algorism...

vertical circle

(Encyclopedia)vertical circle, in astronomy, the great circle on the celestial sphere that passes from the observer's zenith through a given celestial body. In the altazimuth coordinate system the altitude of a bod...

Cornu, Marie Alfred

(Encyclopedia)Cornu, Marie Alfred märēˈ älfrĕdˈ kôrnüˈ [key], 1841–1902, French physicist. From 1867 he was professor at the École polytechnique, Paris. He measured the velocity of light and made import...

culminate

(Encyclopedia)culminate, in astronomy, the maximum height in the sky reached by a celestial body on a given day. At the culminate the body is crossing the observer's celestial meridian and is said to be in upper tr...

inclination

(Encyclopedia)inclination, in astronomy, the angle of intersection between two planes, one of which is an orbital plane. The inclination of the plane of the moon's orbit is 5°9′ with respect to the plane of the ...

Beta Crucis

(Encyclopedia)Beta Crucis kro͞oˈsĭs [key]: see Mimosa, in astronomy. ...

communications industry

(Encyclopedia)communications industry, broadly defined, the business of conveying information. Although communication by means of symbols and gestures dates to the beginning of human history, the term generally ref...

electromagnetic radiation

(Encyclopedia)CE5 Electromagnetic spectrum electromagnetic radiation, energy radiated in the form of a wave as a result of the motion of electric charges. A moving charge gives rise to a magnetic field, and if ...

nadir

(Encyclopedia)nadir nāˈdər [key] [Arab.,=opposite], in astronomy, the point on the celestial sphere directly opposite the zenith, i.e., directly beneath the observer. ...

right ascension

(Encyclopedia)right ascension, in astronomy, one of the coordinates in the equatorial coordinate system. The right ascension of a celestial body is the angular distance measured eastward from the vernal equinox alo...