Merrillville Community Planetarium
Bringing the Universe to the Merrillville Schools and Northwest Indiana

Enceladus Revisited

NASA’s Cassini spacecraft at Saturn is revisiting the icy moon Enceladus. Scientists are trying to figure out the history of this unusual moon. Images of the northern polar region will be viewed this time in three passbys. The southern polar region was viewed early in Cassini’s mission. Now, with the north in summer, Cassini can see and reveal more about it.

In 2005, Cassini discovered continually-erupting fountains of icy material in the southern hemisphere. Mission scientists believe the hydrothermal activity may be from the seafloor of the underground ocean. They recently discovered the underground ocean was not regional, but global! A global ocean under the surface, with a rocky core under that, explains the slight wobble of the small, icy moon. Enceladus probably has more water than Earth’s oceans. Enceladus is a good place to look for habitable environments. The ocean floor may be like Earth’s ocean floor with thermal vents. High-resolution images show the spidery network of cracks through craters in the north just like the south.

The last fly-by will occur in December. Scientists will examine how much heat is coming from the moons interior. Cassini will get a sample of the icy spray to sample the chemistry of the interior ocean. Cassini has 2 more years left in its mission at Saturn.

To look at the Enceladus flybys, go to For the Cassini mission, go to or