spiral arm Beautiful spiral galaxy has a few long arm - arm, crowded with dense spiral arms of stars and gas and dust. However, the presence of spiral arms is puzzling. In general, the force of gravity, the galaxy should be a flat disk, can not form a vortex structure. Even if the temporary spiral arms in the galaxy's rotation process, because by the fast rotating star inside, outside turn slowly, the spiral arms of galaxy formation will soon wrapped tight. But from the Milky Way was born to now, the sun around the galactic center has been rotated more than twenty laps, but did not find arm wrapped tight. How did this happen? Density wave theory can better answer this question. density wave is a vivid metaphor. Suppose there is a road being renovated, the road, leaving only a narrow channel, then this place will become very crowded, even though car or a vehicle went by, if the bird's eye view from the sky, as if to see here all day long packed with vehicles. In the galaxy, the spiral arms as if sections of the renovation, this place more stars, the gravitational strength, so not only to attract a lot of gas and dust, and when the star passed here, are slowed down, so here seem crowded, well looked for showing a vortex-like structure. In fact, the spiral arms of the star is constant motion, change the. spiral density wave in the end just tell us what is, as to why is the formation of such a density distribution, or a not shrouded in mystery.
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No. 2
spiral arm Milky Way has four spiral arms, namely Sagittarius Arm, Orion Arm, Perseus arm, swan arms. The sun is located inside the Orion Arm. Milky Way is a spiral galaxy, there are two or more spiral arms. Milky Way spiral arm in the study, the optical method is very restricted. Beautiful spiral galaxy has a few long arm - arm, crowded with dense spiral arms of stars and gas and dust. However, the presence of spiral arms is puzzling. In general, the force of gravity, the galaxy should be a flat disk, can not form a vortex structure. Even if the temporary spiral arms in the galaxy's rotation process, because by the fast rotating star inside, outside turn slowly, the spiral arms of galaxy formation will soon wrapped tight. But from the Milky Way was born to now, the sun around the galactic center has been rotated more than twenty laps, but did not find arm wrapped tight. How did this happen? Density wave theory can better answer this question. density wave is a vivid metaphor. Suppose there is a road being renovated, the road, leaving only a narrow channel, then this place will become very crowded, even though car or a vehicle went by, if the bird's eye view from the sky, as if to see here all day long packed with vehicles. In the galaxy, the spiral arms as if sections of the renovation, this place more stars, the gravitational strength, so not only to attract a lot of gas and dust, and when the star passed here, are slowed down, so here seem crowded, well looked for showing a vortex-like structure. In fact, the spiral arms of the star is constant motion, change the. spiral density wave in the end just tell us what is, as to why is the formation of such a density distribution, or a not shrouded in mystery.