Photo from NASA's Astronomy Picture of the Day website. And some related text from TIME:
Enceladus has always been thought of as one of the more remarkable members of Saturn's marble bag of satellites. For one thing, it's dazzlingly bright. The percentage of sunlight that a body in the solar system reflects back is known as its albedo, and it's determined mostly by the color of the body's ground cover. For all the silvery brilliance of a full moon on a cloudless night, the albedo of our own drab satellite is a muddy 12%, owing mostly to the gray dust that covers it. The albedo of Enceladus, on the other hand, approaches a mirror-like 100%. Such a high percentage likely means the surface is covered with ice crystals -- and, what's more, that those crystals get regularly replenished...
Most remarkably, Enceladus orbits within Saturn's E ring -- the widest of the planet's bands -- and just behind the moon is a visible bulge in the ring, the result of the sparkly exhaust from ice volcanoes that trails Enceladus like smoke from a steamship. It's that cryovolcanism that's responsible for the regular repaving...
In 2008, Cassini confirmed that the cryovolcanic exhaust is ordinary water, filled with carbon dioxide, carbon monoxide, potassium salts and other organic materials. Tidal pumping -- or gravitational squeezing -- by Saturn and the nearby sister moons Tethys and Dione keeps the interior of Enceladus warm, its water deposits liquid and the volcanoes erupting....
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