This view of Saturn’s moon Enceladus narrowly above the planet’s ring plane was captured by the narrow-angle camera of NASA’s Cassini spacecraft on 29 July 2015 at a distance of approximately 630,000 miles (1.0 million kilometres) from Enceladus. Enceladus is subject to forces that heat a global ocean of liquid water under its icy surface, resulting in its famous south polar water jets which are just visible below the moon’s dark, southern limb. Image credit: NASA/JPL-Caltech/Space Science Institute.Although Enceladus and Saturn’s rings are largely made up of water ice, they show very different characteristics. The small ring particles are too tiny to retain internal heat and have no way to get warm, so they are frozen and geologically dead. Enceladus, on the other hand, is subject to forces that heat its interior to this very day. This results in its famous south polar water jets, which are just visible below the moon’s dark, southern limb, along with a sub-surface ocean.
Recent work by Cassini scientists suggests that Enceladus (313 miles or 504 kilometres across) has a global ocean of liquid water under its surface. This discovery increases scientists’ interest in Enceladus and the quest to understand the role of water in the development of life in the solar system.
This view looks toward the unilluminated side of the rings from about 0.3 degrees below the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on 29 July 2015.
The view was acquired at a distance of approximately 630,000 miles (1.0 million kilometres) from Enceladus and at a Sun-Enceladus-spacecraft, or phase angle of 155 degrees. Image scale is 4 miles (6 kilometres) per pixel.
NASA’s Cassini spacecraft has observed geysers erupting on Saturn’s icy moon Enceladus since 2005, but the process that drives and sustains these eruptions has remained a mystery. Now, scientists have pinpointed a mechanism by which cyclical tidal stresses exerted by Saturn can drive Enceladus’s long-lived eruptions.
It may look as though Saturn’s moon Mimas is crashing through the rings in this image taken by NASA’s Cassini spacecraft, but Mimas is actually 45,000 kilometres (28,000 miles) away from the rings.
You might think that, in the rings of Saturn, more opaque areas contain a greater concentration of material than places where the rings seem more transparent. But this intuition does not always apply, according to a recent study of the rings using data from NASA’s Cassini mission. The research also suggests that the planet’s brightest B ring could be a few hundred million years old instead of a few billion.
