An Improved Theory for Galaxy Rotation

May 29th, 2008 | By CentroN | Category: Astronomy

Galaxy Spiral Arm Stability and Dynamics

Simple Newtonian gravitation is sufficient to explain the entire behavior of Galaxy Spiral Arms. The well-known Keplerian effect certainly dominates, but a Spiral Arm also has internal mutual gravitation, which has surprisingly strong effects!

The stability of galaxy spiral arms has long troubled the Astrophysics community. It has been assumed that ONLY the Keplerian central force was acting, as suggested in the drawing at the right. The orange dot represents the Sun. If we assume that the Sun is revolving in the Milky Way Galaxy with a velocity of 250 km/sec, and that the Sun is around 28,000 light years from the center of the Galaxy, it is easy to calculate that a centripetal (Keplerian) acceleration must exist of a = v2/r or 2.36 * 10-10 meters/second2. This acceleration must also equal G * Mgalaxy/r2 which tells us that the effective Keplerian mass of the Galaxy is around 125 billion solar masses. This is ONLY true if ONLY a Keplerian central force is causing the Sun to have its revolution motion.

Source: Public Service Projects

Tags: Galaxy Rotation, gravitation, Astrophysics, Star Cluster