Article Posted on : - Apr 08, 2011

Four moons huddle near Saturn's multi-hued disk. Photo by NASA/JPL-Caltech/Space Science Institute.

PASADENA, CALIFORNIA (BNS): The interior of Saturn’s moon Titan may be cool and dormant and incapable of causing active ice volcanoes, a new theory suggests.

"It would be fantastic to find strong evidence that clearly shows Titan has an internal heat source that causes ice volcanoes and lava flows to form," said Jeff Moore, lead author of the paper published in the April 2011 edition of the journal Icarus.

The planetary scientist at NASA's Ames Research Center added, "But we find that the evidence presented to date is unconvincing, and recent studies of Titan's interior conducted by geophysicists and gravity experts also weaken the possibility of volcanoes there."

Some scientists theorize ice volcanoes exist and suggest energy from an internal heat source may have caused ice to rise and release methane vapours as it reached Titan's surface.

But in the new paper, the authors conclude that the only features on Titan's surface that have been unambiguously identified were created by external forces -- such as objects hitting the surface and creating craters; wind and rain pummeling its surface; and the formation of rivers and lakes.

Titan, Saturn's largest moon, is the only known moon to have a dense atmosphere, composed primarily of nitrogen, with two to three percent methane.

Titan's dense atmosphere makes its surface very difficult to study with visible-light cameras, but infrared instruments and radar signals can peer through the haze and provide information about both the composition and shape of the surface.

One goal of the Cassini mission is to find an explanation for what, if anything, might be maintaining this atmosphere. The Cassini spacecraft, currently orbiting Saturn, continues to make fly-bys of Titan.