Columbia Encyclopedia

Search results

434 results found

mass-luminosity relation

(Encyclopedia)mass-luminosity relation, in astronomy, law stating that the luminosity of a star is proportional to some power of the mass of the star. More massive stars are in general more luminous. For stars on t...

Heliopolis, ancient city, Egypt

(Encyclopedia)Heliopolis hēlēŏpˈəlĭs [key] [Gr.,=city of the sun], ancient city, N Egypt, in the Nile delta, 6 mi (10 km) below modern Cairo. It was noted as the center of sun worship, and its god Ra or Re wa...

Hertzsprung, Ejnar

(Encyclopedia)Hertzsprung, Ejnar īˈnär hĕrtsˈspro͞ong [key], 1873–1967, Danish astronomer. Although trained as a chemical engineer, Hertzsprung made his career in astronomy, specializing in exacting photogr...

Poisson, Siméon Denis

(Encyclopedia)Poisson, Siméon Denis sēmāôNˈ dənēˈ pwäsôNˈ [key], 1781–1840, French mathematician and physicist. From 1802 he taught at the École polytechnique, Paris, and was also on the faculty of sc...

Adams, John Couch

(Encyclopedia)Adams, John Couch, 1819–92, English astronomer, grad. St. John's College, Cambridge, 1843. By mathematical calculation based on irregularities in the motion of Uranus, he predicted the position of t...

blue shift

(Encyclopedia)blue shift or blueshift, in astronomy, the systematic displacement of individual lines in the spectrum of a celestial object toward the blue, or shorter wavelength, end of the visible spectrum. The am...

Bode, Johann Elert

(Encyclopedia)Bode, Johann Elert yōˈhän āˈlĕrt bōˈdə [key], 1747–1826, German astronomer. From 1772 to 1825 he was astronomer of the Academy of Science, Berlin, and from 1786, director of the Berlin Obse...

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...

Koshiba, Masatoshi

(Encyclopedia)Koshiba, Masatoshi, 1926–2020, Japanese physicist, Ph.D. Univ. of Rochester, 1955. He was a professor at the Univ. of Tokyo from 1958 (emeritus from 1987) and at the Univ. of Tokai from 1987 to 1997...

Freycinet, Louis Claude Desaulses de

(Encyclopedia)Freycinet, Louis Claude Desaulses de də frāsēnāˈ [key], 1779–1842, French marine officer. He was assigned (1800) to a French exploring expedition in Australian waters; after his return to Pari...