Magellanic Clouds definition of Magellanic Clouds in the Free Online Encyclopedia.

Magellanic Clouds (măj'əlăn`ĭk), two dwarf galaxies located in the far southern sky and visible to the unaided eye; they are classified as irregular because they show no definite symmetry or nucleus. The larger of the two, known as the Large Magellanic Cloud (LMC), is located mostly in the constellation Dorado; its angular diameter measures approximately 7°. The Small Cloud (SMC) is almost completely in the constellation Tucana, and measures approx. 4° in diameter. Both are nearly 160,000 light-years from the earth. They are part of the Local Group Local Group, in astronomy, loose cluster of at least 35 nearby galaxies , including our own Milky Way galaxy, the Andromeda Galaxy , and the Magellanic Clouds .
..... Click the link for more information. of galaxies, which includes our own galaxy (the Milky Way Milky Way, the galaxy of which the sun and solar system are a part, seen as a broad band of light arching across the night sky from horizon to horizon; if not blocked by the horizon, it would be seen as a circle around the entire sky.
..... Click the link for more information. ) and the Andromeda Galaxy Andromeda Galaxy, cataloged as M31 and NGC 224, the closest large galaxy to the Milky Way and the only one visible to the naked eye in the Northern Hemisphere. It is also known as the Great Nebula in Andromeda. It is 2.
..... Click the link for more information. , and are the nearest extragalactic objects. The Magellanic Clouds, named for the Portuguese navigator Magellan, were first studied in detail by Sir John Herschel in the 19th cent. While studying Cepheid variable Cepheid variables (sē`fēĭd), class of variable stars that brighten and dim in an extremely regular fashion.
..... Click the link for more information. stars in the SMC, Henrietta Leavitt discovered (1912) the period-luminosity relation. This relation offered a technique for measuring the distances of stars and galaxies. In Feb., 1987, Supernova 1987A erupted in the LMC. The first supernova visible without a telescope since 1604, this star gradually brightened over the next few months and remains under careful observation as it fades. The diffuse nebulae in both the LMC and the SMC appear to have fewer "metals" (elements heavier than helium); the deficiency is much more pronounced in the SMC.

Magellanic Clouds [¦maj·ə¦lan·ik ′klau̇dz]

(astronomy)

Two irregular clouds of stars that are the nearest galaxies to the galactic system; both the Large and Small Magellanic Clouds are identified as Irregular in the classification of E.P. Hubble. Also known as Nubeculae.