Saturns moon Enceladus may be more dynamic than previously believed

December 16th, 2008 - 12:52 pm ICT by ANI  

Washington, Dec 16 (ANI): Latest flybys of Saturns moon Enceladus made by NASAs Cassini spacecraft have provided more evidence of an active world, with ongoing changes spotted on and around the moon.

The latest high-resolution images of Enceladus show signs that the south polar surface changes over time.

Close views of the southern polar region, where jets of water vapor and icy particles spew from vents within the moons distinctive tiger stripe fractures, provide surprising evidence of Earth-like tectonics.

They yield new insight into what may be happening within the fractures.

The latest data on the plume, which is the huge cloud of vapor and particles fed by the jets that extend into space, show it varies over time and has a far-reaching effect on Saturns magnetosphere.

Of all the geologic provinces in the Saturn system that Cassini has explored, none has been more thrilling or carries greater implications than the region at the southernmost portion of Enceladus, said panel member Carolyn Porco, Cassini imaging team leader at the Space Science Institute in Boulder, Colorado.

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.

According to Helfenstein, Enceladus has asymmetric spreading on steroids. 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.

Using Cassini-based digital maps of the moons south polar region, 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 finding that the remaining sections fit together like puzzle pieces.

Images from recent close 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.

Over time, the particles that rain down onto the surface from the jets may form a continuous blanket of snow along a fracture, Porco said.

Enceladus output of ice and vapor dramatically impacts the entire Saturnian system by supplying the ring system with fresh material and loading ionized gas from water vapor into Saturns magnetosphere.

With water vapor, organic compounds and excess heat emerging from Enceladus south polar terrain, scientists are intrigued by the possibility of a liquid-water-rich habitable zone beneath the moons south pole. (ANI)

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