megellanic clouds :: essays research papers fc

  Ã‚  Ã‚  Ã‚  Ã‚  Clouds are usually the last things astronomers want to see in the sky, but for those who observe in the southern hemisphere there is a notable exception to that celestial rule.   Ã‚  Ã‚  Ã‚  Ã‚  The Large and Small Magellanic Clouds are among the highlights of the southern night sky. Only within the last century were astronomers able to verify their true nature. Although they seem to be two foggy patches possibly torn from the Milky Way, astronomers believe these are actually small galaxies gravitationally bound to the Milky Way like moons around a giant planet. The two Clouds of Magellan are like binary stars that gravity draws together to form a satellite galaxy. Of all the galaxies in the entire Universe these are the closest to our galactic system. About 170,000 light-years away from the Milky Way galaxy lie the Large Magellanic Cloud. With only 15 billion young bright stars, it is just one-quarter the size of our own galaxy. During the winter of 1987, a Canadian astronomer, Ian Shelton, spotted the first naked eye supernova since 1604, the result of a massive explosion. No more exciting and scientifically significant event has occurred over the last decade in science than Supernova 1987A, as it is known. Photographs taken on the night of February 23, 1987, of the Large Magellanic Cloud, a companion galaxy to our own Galaxy, at Canada's southern hemisphere observatory at La Silla, Chile, and at the Siding Springs Observatory in Australia, revealed a 6th-magnitude object where only 12th-magnitude blue supergiant stars had been observed before. Scientists believe that the progenitor of Supernova 1987A is a typical blue supergiant of spectral type B3. Spectra taken in 1977 do not suggest anything unusual happening in the outer layers of the star prior to undergoing the supernova outburst. This is not surprising since the real changes were occurring deep inside in a relatively tiny portion of the star's radius. The Large Cloud is quite important because it is the location of this Supernova 1987A, the exploded star that for a time shone brightly but that is now dim and dead.   Ã‚  Ã‚  Ã‚  Ã‚  Farther away than the Large Cloud, the Small Magellanic Cloud is approximatly 200,000 light-years distant. It is roughly a third the size of the Large Cloud, consisting of only 5 billion older stars. The nebulas were named after Portuguese explorer Ferdinan Magellan, the first person to sail around the world.