Enceladus and the Rings
For 2 months Cassini has been in a high-inclination orbit around Saturn, allowing views of the polar regions. This photo from January 17 shows the moon Enceladus orbiting with the Rings. The moon's orbit is within the tenuous E Ring. Eruptions from the polar "hot spot" resupply this Ring. If they were not replenished, the Rings would dissipate within 100,000 years. There must be other sources maintaining the other Rings.
Saturn's Rings show conditions similiar to the solar system's formation. They are full of unexplained phenomena--the Enceladus hot spot, spokes believed caused by electromagnetic discharges, even cone-shaped jets of radiation issuing from the Rings. These phenomena could be explained by the presence of singularities. This would be an excellent place to search.