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spectral class
(Encyclopedia) CE5 spectral class, in astronomy, a classification of the stars by their spectrum and luminosity. In 1885, E. C. Pickering began the first extensive attempt to classify the stars spectroscopically....quasar
(Encyclopedia)quasar kwāˈsär [key], one of a class of blue celestial objects having the appearance of stars when viewed through a telescope and currently believed to be the most distant and most luminous objects...retrograde motion
(Encyclopedia)retrograde motion, in astronomy, real or apparent movement of a planet, dwarf planet, moon, asteroid, or comet from east to west relative to the fixed stars. The most common direction of motion in the...red shift
(Encyclopedia)red shift or redshift, in astronomy, the systematic displacement of individual lines in the spectrum of a celestial object toward the red, or longer wavelength, end of the visible spectrum. The effect...Kuiper, Gerard Peter
(Encyclopedia)Kuiper, Gerard Peter or Gerrit Pieter gĕrˈĭt pēˈtər kīˈpər [key], 1905–73, American astronomer, b. the Netherlands. Kuiper is considered to be the father of modern planetary science for his...Ptolemy
(Encyclopedia)Ptolemy (Claudius Ptolemaeus), fl. 2d cent. a.d., celebrated Greco-Egyptian mathematician, astronomer, and geographer. He made his observations in Alexandria and was the last great astronomer of ancie...Thomas, Dylan
(Encyclopedia)Thomas, Dylan dĭlˈən [key], 1914–53, Welsh poet, b. Swansea. An extraordinarily individualistic writer, Thomas is ranked among the great 20th-century poets. He grew up in Swansea, the son of a te...Silk Road
(Encyclopedia)Silk Road, ancient overland trade route linking Asia and Europe, consisting of a network of caravan routes running from China across central Asia to the shores of the Mediterranean. Its starting point...Peirce, Charles Sanders
(Encyclopedia)Peirce, Charles Sanders pûrs [key], 1839–1914, American philosopher and polymath, b. Cambridge, Mass., grad. Harvard, 1859; son of Benjamin Peirce. Except for occasional lectures he renounced the r...transit
(Encyclopedia)transit, in astronomy, passage of a body across a meridian or passage of a small body across the visible disk of a larger one. (The passage of a large body across a smaller one is called an eclipse or...Browse by Subject
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