Hard balls gas and Alexandrov spaces of curvature bounded above.
Hill problem analytical theory to the order four: application to the computation of frozen orbits around planetary satellites.
Hydrodynamics of Saturn’s Dense Rings
The space missions Voyager and Cassini together with earthbound observations revealed a wealth of structures in Saturn’s rings. There are, for example, waves being excited at ring positions which are in orbital resonance with Saturn’s moons. Other structures can be assigned to embedded moons like empty gaps, moon induced wakes or S-shaped propeller features. Furthermore, irregular radial structures are observed in the range from 10 meters until kilometers. Here some of these structures will be discussed...