Enceladus

By Ciara Graf

What's in a name?

The name "Enceladus" comes from a mythological Greek tale of a giant. (Enceladus was the giant's name.) This character had one hundred arms, and was said to have battled the Greek gods. He was killed in battle by Zeus, and legend has it that he was buried beneath Mt. Etna of Sicily.

Perhaps this is a symbol of the unknown underground energy that drives the geysers of the existing Enceladus. The real Enceladus is the sixth largest of the many moons of Saturn, with a diameter of 504 kilometers (313 miles). It also happens to be the most reflective (known) celestial body in our solar system. Almost 100% of the light hitting it shines back. A smooth, icy surface contributes to the reflective ability.

This natural satellite was discovered by William Herschel with a telescope in 1789. A majority of human knowledge about Enceladus came from the U.S. spacecraft Cassini, whose first visit to Enceladus occurred in 2005, when it sampled the moon's geysers. It has been discovered that most of the particles that they spray are made of water ice. A minority of the particles contain carbon. Molecules containing carbon are referred to as organic.

Enceladus circles Saturn in the densest part of the E ring. On average, the moon tends to be 238,000 kilometers (148,000 miles) from its planet. It orbits Saturn every 1.4 days

Plume Moon

Enceladus has multiple mysterious plumes, or geysers, that shoot tiny particles from the south polar area of the moon's surface, as previously mentioned. One might ask, "What is so mysterious about that?" As of yet, scientists are unsure what forces drive these geysers. Many theories have been formed, however. One suggests that gravitational forces being exchanged between Saturn, Enceladus, and the other moons cause Enceladus's insides to flex. The energy from this could create tidal heating, thereby driving the geysers. Another theory supposes that the rocks in this moon may have isotopes, that create energy and heat when they decay, setting the plumes off. Inside chemistry may also affect the geysers.

Whatever force is making the plumes spray, scientists have discovered that it has much more energy than they previously thought possible! In the year 2007, they estimated that the gravitational interactions between the nearby moon Dione and Enceladus could only create a tidal force of a maximum 1.1 gigawatts, and that radioactivity could only generate up to .3 more gigawatts. However, it was discovered in 2008 from a reading from Cassini that there was a lot more energy there than previously presumed. (See picture below.) Now it is hypothesized that Enceladus's energy production changes frequently, and that Cassini caught it in a particularly "energetic" time.

Tiger Stripes

The Tiger Stripes are four trenches on Enceladus's surface that are fairly parallel. They are the origin of the plumes- much of the spray comes from here. These trenches are approximately 130 kilometers (80 miles) long, and 2 kilometers (1 mile) wide each. This area of Enceladus is much warmer because of the energy being spewed forth in the geysers.

NASA Video on Enceladus Discoveries

Enceladus - Saturns moon

Sources

Pictures

In order of appearance:

Video Clip

Enceladus - Saturns moon. Dir. stevebd1. 7 Aug. 2007. YouTube. Web. 3 Apr. 2013. <http://www.youtube.com/watch?v=rBhAPz5pqYg>.