Until recently, Saturn's tiny moon Enceladus was thought to be cold and dead. But close observations by the Cassini spacecraft have revealed dramatic features and made this frozen world a new target in NASA's search for life.

With a diameter of about 300 miles, Enceladus is much smaller than Earth's moon.

It would fit easily between Los Angeles and San Francisco. Its surface is covered with snowy water ice, making it the brightest object in our solar system. Much of its terrain is old and cratered, while large expanses are relatively young and uncratered.

In July of 2005, the Cassini mission revealed an amazing surprise: a hot spot on Enceladus' south pole. Here, the landscape is fractured by icy canyons that appear to have formed in the recent past. What should have been a geologically dead world appeared to be active.

This mysterious hot zone is the source of Enceladus' most striking feature.

Towering plumes of ice particles and water vapor erupt like geysers from the south pole. These fountains extend hundreds of miles into space and are a major source of material that makes up Saturn's vast E ring.

These discoveries have raised many new questions about Enceladus. Could the source of the plumes be liquid water below the surface? What is providing the moon's internal heat? Could this be an environment hospitable to life? In the months to come, Cassini will again fly close to Enceladus. It will pass directly through the plumes to obtain additional data, and perhaps unlock more secrets of this strange and dynamic world.