Lord of the Rings Trivia Quiz

Answer: Cassini-Huygens

Dutch astronomer Christiaan Huygens was the first person to discover that Saturn had a ring. He also discovered Saturn's largest moon Titan. Giovanni Cassini discovered four more moons: Japetus (or Iapetus), Rhea, Tethys and Dione. He also discovered the biggest opening within the rings, which we now call the Cassini Division.

In 1997 NASA launched the Cassini-Huyghens mission. After a seven year journey the spacecraft entered in orbit around Saturn. The spacecraft consists of two parts: the Cassini orbiter and the Huygens probe. In December 2004 Huygens separated from the orbiter. In January 2005 the probe started its descent towards Titan's surface. It revealed that there are lakes and rivers on Titan, only they are made of liquid methane rather than water.

Cassini stayed in orbit around Saturn and has sent us invaluable information about the planet, the moons and the rings.

Answer: Chunks of ice

The rings of Saturn look massive but they're not. Each ring consists of thousands of smaller rings that consist of billions of chunks of mostly ice. Most of these ice particles are smaller than 1 centimetre, but some are larger with a diameter up to 1 km.

Although the rings are very old they're still very bright. During their orbit around Saturn the particles constantly collide what makes them clump up and then fall apart again. This way shiny new ice is created all the time. Because of this the rings still reflect the sunlight as much as during the time they were created.

Answer: True

Bearing in mind that Saturn's rings are approximately 100,000 km (60,000 miles) wide they are incredibly thin. The thickness of the rings varies from only three meters to approximately one km.

Answer: False

No, it's the other way round. Saturn, with its rings and moons, represents a miniature version of the early solar system. Saturn represents the sun and the moons represent the planets. From studying the interaction between the Saturn, the rings and the moons scientist hope to discover more information about how our solar system was formed. Just like the planets closest to the sun the rings closest to Saturn orbit the fastest, up to 80,000 km/h (50,000 mi/h).

Answer: Mimas

The Cassini Division is the big gap between the A ring and B ring, first discovered by Giovanni Cassini. Mimas orbits Saturn far outside the rings. Particles in the Cassini Division orbit Saturn twice every time Mimas orbits it once. This means the force of gravity exerted on those particles is regular. This alters the orbit of the particles in the Cassini Division, which throws them out and cleans up the gap. This phenomenon is called orbital resonance.

The three wrong answers are moons of Uranus.

Answer: Shepherd moons

Many of the complex structures in the ring system are caused by orbital resonance between the particles in the rings and Saturn's moons. The small moons within the ring system whose gravity influences the shape of the rings and the gaps between them are called 'shepherd moons'. Pan, Daphnis and Atlas are examples of such moons.

Answer: Prometheus

Prometheus and Pandora are the shepherd moons of Saturn's F ring. The two moons have a gravitational influence each other's orbits. When Prometheus comes close to the F ring its gravity pulls particles towards it, thereby changing the ring into a unique spiral shape.

Answer: Tiger stripes

Enceladus is a small moon made of mainly ice. The northern hemisphere has a lot of craters, as you might expect of an icy moon. The southern hemisphere however has a smooth surface with cracks and gullies. Near the south pole there are four parallel cracks with a length of approximately 130 km (80 mi). Those cracks are named the 'tiger stripes' and are similar to tectonic fault lines which we find on earth.

The Cassini orbiter has shown that there are hot areas beneath the tiger stripes, although hot is relative in this case. Whereas the average temperature on Enceladus's surface is -200°C (-328° F) the area around the tiger stripes is 'only' -140°C (-220° F).

Answer: From ice crystals ejected by geysers on Enceladus

Pictures taken by Cassini show huge fountains coming out of Enceladus's tiger stripes. This proves there must be liquid water under Enceladus's icy surface. The geysers on Enceladus are constantly active and shoot off water vapour thousands of kilometres into the sky. Once into space the water vapour immediately freezes into tiny ice crystals. Some of it falls back on Enceladus but most it enters in orbit around Saturn. This is how Saturn's very faint E ring is formed.

It is very surprising that such a small moon so far away from the sun has any geological activity. Most scientist believe this is caused by the elliptical shape of Enceladus's orbit. Sometimes Enceladus is far away from Saturn, sometimes it is close. The gravity that pulls on Enceladus from Saturn changes as Enceladus goes around Saturn, which means the moon flexes and heats up just enough to have some geological activity.

Answer: No, all the gas giants have rings

The three other gas giants (Jupiter, Uranus and Neptune) also have rings. In 1977 Saturn's rings were no longer unique as Uranus's rings were discovered. Although not nearly as spectacular as the one around Saturn, Uranus's ring system is more complex than those of Jupiter and Neptune. Uranus's rings are also much darker than those of Saturn.

The rings of Jupiter were discovered by Voyager 1 in 1979. Neptune was the last planet to have its rings discovered, in 1984. The rings of Jupiter and Neptune are very faint and consist mainly of dust.

The inner planets (Mercury, Venus, Earth and Mars) have no rings.