The Moons of Saturn
Moons of Saturn Full of Surprises
On January 14, 2005, the European Space Agency sent the Huygens spacecraft where none had gone before: to the cloud-shrouded surface of Saturn’s moon, Titan.
Breaking through the moon’s clouds, the Huygens probe took amazing photos of landforms, drainage channels, shorelines and a sea. Instead of water, however, the liquid on the surface is composed of hydrocarbons. The probe landed on the Titan’s surface, sending back pictures and other data for about 90 minutes.
Saturn's Moons: Largest and Smallest
Titan is the only moon in the Solar System to have a substantial atmosphere, which is composed of 95 percent nitrogen and traces of methane. The moon’s extreme cold means it is similar to Earth’s early atmosphere before biology made our planet livable.
Scientists were ecstatic to get such a close look at such an enigmatic moon. As they studied the results, they continued work begun centuries earlier by Dutch astronomer Christiaan Huygens, who discovered Titan as the first moon of Saturn in 1655. The Huygen’s probe was dropped off by NASA’s Cassini orbiter, which was named after Giovanni Domenico Cassini, who discovered the planet’s next four moons: Iapetus, Rhea, Dione and Tethys.
Scientists have now discovered 62 moons of Saturn. The satellites range in size from Titan, which at 5,150 km (3,200 miles) is the second largest moon in the Solar System, to tiny moonlets that orbit inside and just outside of Saturn’s enormous rings.
Astronomers know quite a bit about the moons of Saturn thanks to the Voyager 1 and Voyager 2 spacecraft, which flew by Jupiter in the early 1980’s, and the Cassini orbiter, which entered orbit in July 2004. Cassini has been able to fly closely to many of Saturn’s moons.
Evaporating ice escapes to form a large cloud of water vapor above the south pole of Enceladus.
Enceladus is volcanically active, with fractures through which evaporating ice escape to form a large cloud of water vapor above the south pole. Cassini has sent back spectacular images of the volcanoes erupting. Subsequent analysis has suggested that the source is a sub-surface body of liquid water with a unique chemical signature. In May 2011, NASA scientists declared that Enceladus "is emerging as the most habitable spot beyond Earth in the Solar System for life as we know it".
Analysis has suggested that the source of these jets on Enceladus is a sub-surface body of liquid water.
Saturn’s satellites are essential to the functioning of the planet’s enormous rings. Pan orbits within gaps in the main rings. Other “shepherding” satellites such as Prometheus and Pandora interact with ring materials, keeping the rings together.
Saturn’s other moons have fascinating characteristics:
- Iapetus is two-faced, with one side extremely dark and the other as bright as snow;
- Mimas has an enormous crater that makes it resemble the Death Star from the Star Wars movies;
- Phoebe and several other moons have retrograde orbits that are the reverse of Saturn’s largest moons;
- Sixteen moons are tidally locked, meaning that – like the Earth’s moon – they always show the same face to Saturn.
The 62 moons of Saturn are a mini-Solar System with many secrets yet to be discovered. Scientists will be analyzing the data from Cassini and Huygens for many years to come.
Links for Moons of Saturn