Whirlpool Galaxy • M51 • NGC 5194 Personal or Business Card. This Hubble photo is giving astronomers an unprecedented view of the intricate structure of the Whirlpool's spiral arms and dust clouds. Astronomers are seeing dust "spurs" along the spiral arms that branch out almost perpendicular to the main spiral arms. The regularity and large number of these spurs suggests that astronomers may have to rethink the popular theory that a spiral galaxy has two arms. The new image also reveals a dust disk in the center of the galaxy, which may feed a black hole. NOTE: this photgraph has been brightened and enhanced for artistic effect. Photograph courtesy NASA.