... Accretion Disk Binary System . ... Our Sun is unusual in that it is alone - most stars occur in multiple or binary systems. ... Uranus' Moon Miranda . ... The third and fourth innermost moons of Saturn were unexpectedly discovered to be gravitational "shepards." ... The energetic light from these stars strikes hydrogen atoms in the surrounding nebula causing them to lose their electrons. A Galaxy Gravitational Lens . ... The central galaxy happens to fall directly in the light path of the quasar. ...