Astronomy Chapter 12 Vocab- "Saturn"

Saturn’s Orbital and Physical Properties

• Radius is approximately 10 times greater than Earth’s

• Density is 0.7g/cm³, which is less than water

• Rotation is rapid enough to flatten planet considerably and differential

• Rings are very prominent and reflective

D ring, C ring, B ring, Cassini Division, A ring, Encke Gap, F ring, G ring, E ring

the order of Saturn’s 7 ring systems, going from closest to farthest from the planet

Roche limit

the closest distance to a planet that a moon can survive in; all of Saturn’s ring systems are inside this limit

radial “spokes”

dark radial markings that are caused by small particles suspended above the ring plane

Mimas, Enceladus, Tethys, Dione, Rhea, and Iapetus

the six medium-sized moons of Saturn

Titan

Saturn’s only large moon; almost as large as Jupiter’s Ganymede and has an atmosphere thicker and denser than Earth’s

Huygens

a probe on Cassini that was designed to fall to the surface of Titan; marked the first outer Solar System landing

Mimas, Tethys, Dione, Rhea, and Iapetus

the moons of Saturn that are tidally locked; all of them except for one orbit between 3 and 9 planetary radii

planetary radii

the distance between a planet’s center and its surface

tidally locked

when the same side or surface of a moon always faces a planet

Janus and Epimetheus

the two small moons of Saturn that swap orbits

Telesto and Calypso

the two moons of Saturn that are at the “Lagrangian points” of slightly-larger Tethys

Lagrangian points

positions in space where the gravitational forces of a two-body system (ex. the Sun and Earth) produce enhanced regions of attraction and repulsion