globular star clusters. It is estimated that our galaxy has about 200 globulars, but we know about 150. These globular clusters are consolidated toward the Galactic Center. Harlow Shapley concluded that the center of the Milky Way lies at a cpnsiderable distance in the direction of Sagittarius. He came to his conclusions because of the distribution of the clusters. http://seds.lpl.arizona.edu/messier/more/mw_cobe.htmlThe Milky Way Galaxy belongs to the Local Group, a smaller group of 3 large and over 30 small galaxies, and is the second largest (after the Andromeda Galaxy M31) but perhaps the most massive member of this group. M31, at about 2.9 million light years, is the nearest large galaxy, but a number of faint galaxies are much closer: Many of the dwarf Local Group members are satellites or companions of the Milky Way. The closest of all is SagDEG at about 80,000 light years from us and some 50,000 light years from the Galactic Center, followed by the more conspicuous Large and Small Magellanic Cloud at 179,000 and 210,000 light years, respectively.The Milky Way is a gravitationally bound collection of roughly a hundred billion stars. Our Sun is one of these stars and is located roughly 24,000 light years (or 8000 parsecs) from the center of our the Milky Way. Our solar system is thus situated within the outer regions of our galaxy, well within the disk and only about 20 light years above the equatorial symmetry plane but about 28,000 light years from the Galactic Center. Therefore, the Milky Way shows up as luminous band spanning all around the sky along this symmetry plane, which is also called the "Galactic Equator". http://map.gsfc.nasa.gov/html/milky_way.htmlOur galaxy is truly gigantic. Shapley came up with a process to determine just how big our galaxy is. First, he showed that most globular clusters reside at great distances, many thousands of parsecs, from the Sun. Second, by measuring the direction and distance o...
