Milky+Way

Milky Way is galaxy which is the Solar System is loacted. it is one of billions of galaxies in the observable universe. The Milky Way is believed to be more than 13 billions years old, which is estimateto be as old as the entire Universe itself. Milky way is just one of billions of galaxies contain within the Universe. the Milky Way has whopping circunference of roughly 250-300 thousand light years. within the main body of Milky Way is estimate between 200 and 400 billons stars. The Sun is revolving around the center of the Galaxy at a speed of half a million miles per hour, yet it will still take 200 million years for it to go around once. The galaxy's bar is thought to be about 27,000 light-years long, running through the center of the galaxy at a 44 ± 10 degree angle to the line between our sun and the center of the galaxy. It is composed primarily of red stars, believed to be ancient. The bar is surrounded by a ring called the "5-kpc ring" that contains a large fraction of the molecular hydrogen present in the galaxy and most of the Milky Way's star formation activity. Viewed from the Andromeda Galaxy, it would be the brightest feature of the Milky Way. Each spiral arm describes a logarithmic spiral (as do the arms of all spiral galaxies) with a pitch of approximately 12 degrees. There are believed to be four major spiral arms which all start at the Galaxy's center. These are named as follows, according to the image at left:
 * The halo - a roughly spherical distribution which contains the oldest stars in the Galaxy,
 * The nuclear bulge and Galactic Center.
 * The disk, which contains the majority of the stars, including the sun, and virtually all of the gas and dust

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