Cassini continues to pay big dividends!

Lots of cool images, and even a short flash movie clip that illustrates where the most prominent jets of vapor/icy particles are coming from (the tiger stripes) Ciclops

"The most recent flybys of Enceladus made by NASA's Cassini spacecraft have provided new signs of ongoing changes on and around the moon. The latest high-resolution images of Enceladus show signs that the south polar surface changes over time....

Enceladus has Earth-like spreading of the icy crust, but with an exotic difference -- the spreading is almost all in one direction, like a conveyor belt," said panelist Paul Helfenstein, Cassini imaging associate at Cornell University in Ithaca, N.Y. "Asymmetric spreading like this is unusual on Earth and not well understood."

Enceladus has asymmetric spreading on steroids," Helfenstein added. "We are not certain about the geological mechanisms that control the spreading, but we see patterns of divergence and mountain-building similar to what we see on Earth, which suggests that subsurface heat and convection are involved."

The tiger stripes are analogous to the mid-ocean ridges on Earth's seafloor where volcanic material wells up and creates new crust. Using Cassini-based digital maps of the south polar region of Enceladus, Helfenstein reconstructed a possible history of the tiger stripes by working backward in time and progressively snipping away older and older sections of the map. Each time he found that the remaining sections fit together like puzzle pieces.

Images from recent close Enceladus flybys also have bolstered an idea the Cassini imaging team has that condensation from the jets erupting from the surface may create ice plugs that close off old vents and force new vents to open. The opening and clogging of vents also corresponds with measurements indicating the plume varies from month to month and year to year.

"We see no obvious distinguishing markings on the surface in the immediate vicinity of each jet source, which suggests that the vents may open and close and thus migrate up and down the fractures over time," Porco said. "Over time, the particles that rain down onto the surface from the jets may form a continuous blanket of snow along a fracture."

SpaceflightNow

Enjoy, Vince

New Cassini mosaic image (from Oct. 5th, 2008):