URSA

MAJOR (" THE

See also:

• GREAT

GREAT

See also:

• BEAR
• BEAR, BLACK
• BEAR, BROWN
• BEAR, GRIZZLY
• BEAR, ISABELLINE
• BEAR, WHITE

BEAR ")  , in astronomy, a constellation of the northern hemisphere, supposed to be referred to in the Old Testament (Job ix . 9, xxxviii . 22), mentioned by Homer, "ApKros 0', riv Kai iiµa av i7rtKX'7o'w KaXiovrac (Il . 18.487), Eudoxus (4th century B.C.) and Aratus (3rd century B.C.) . The Greeks identified this constellation with the nymph Callisto (q.v.). placed in the heavens by Zeus in the form of a bear together with her son Arcas as " bear-warder," or Arcturus (q.v.) ; they named it Arctos, the she-bear, Helice, from its turning round the pole-star . The Romans knew the constellation as Arctos or Ursa; the Arabians termed the quadrilateral, formed by the four stars a, /3,7 , 5, Na'sh, a bier, whence it is sometimes known as Feretrum majus . The Arabic name should probably be identified with the Hebrew name 'Ash and 'Ayish in the book of Job (see G . Schiaparelli, Astronomy in the Old Testament,r9o5) . Ptolemy catalogued 8 stars, Tycho 7 and Hevelius 12 . Of these, the seven brightest (a of the 1st magnitude, [3, y, e, r, sl of the and magnitude, and S of the 3rd magnitude) constitute one of the most characteristic figures in the northern sky; they have received various names—Septentriones, the wagon, plough, dipper and Charles's wain (a corruption of " churl's wain," or peasant's cart) . With the Hindus these seven stars represented the seven Rishis. a and are called the "pointers," since they are collinear with, or point to, the pole-star . E Ursae majoris is a beautiful binary star, its components having magnitudes 4 and 5; this star was one of the first to be recognized as a binary— i.e. having two components revolving about their common centre of gravity—and the first to have its orbit calculated. r Ursae majoris is perhaps the best known double star in the northern hemisphere, the larger component is itself a spectroscopic double .

The nebula M .