Giant Saturn Storm Revealed

Using a distant spacecraft and a giant telescope, astronomers have unmasked the full ire of a storm so big that it encircles Saturn, a planet nearly ten times bigger than Earth. Astronomers have been watching this northern-hemisphere storm since December 2010, when a bright plume of gas bubbled up to the surface of the gaseous sphere that makes up Saturn.

The disturbance has since expanded by riding easterly winds blowing at about 220 miles an hour. But until now very little has been known about the workings of the storm, its depth, and how it affects the ringed planet. Now a new study, released Thursday by the journal Science, says the Saturn storm is about 370 miles tall, according to observations made both by NASA's Cassini probe and the European Southern Observatory's Very Large Telescope array in Chile. By comparison, thunderstorms on Earth usually top out at a height of 12.5 miles—and none of them circle our entire planet, despite its comparatively small size.

Possible Ice Volcano Spied on Saturn Moon

Scientists said they have found the best evidence yet of ice volcanoes on Saturn's giant moon Titan. Unlike volcanoes on Earth, such a volcano on Titan may spew ice and hydrocarbons instead of molten lava. "We finally have some proof that Titan is an active world," said geophysicist Randolph Kirk of the U.S. Geological Survey, who presented the findings.

The latest evidence comes from the international Cassini spacecraft, which spied two peaks over 3,000 feet tall and what looked like old volcanic flows. Researchers said the landforms resembled Mount Etna in Italy or Laki volcano in Iceland. There's no sign of volcanic activity on Titan, though scientists are keeping watch.

Saturn's Strange Propellers Are Clues to Formation

For six years, the Cassini spacecraft has been touring Saturn and its magnificent rings. Unlike previous spacecraft, which have snatched a passing glimpse of the planet on their way to the edges of the solar system, Cassini has beamed back stunningly detailed images year after year. Among the most striking are structures shaped like aircraft propellers. They are the wakes created by unseen moons as they plough through the icy rubble orbiting around Saturn. Dozens of propellers have been spotted in the A-ring, a band 14,000 kilometres wide and only 10 metres deep.

The moons themselves are too small even for Cassini to see directly because they are only a few kilometres to a few hundred metres across. In contrast, their propeller-shaped wakes can be thousands of kilometres long, and some have now been observed orbiting Saturn for several years. They form as a result of a moon's gravity tugging on the surrounding material. The debris inside its orbit, being closer to Saturn, is moving faster, and the perturbation therefore quickly overtakes the moon, creating a long, thin wake ahead of it. This is the leading blade of the propeller. Meanwhile, the material outside the moon's orbit is moving more slowly, creating the trailing blade.