Saturn's moon Enceladus: The mystery of the tiger stripes

The striking tiger stripes at the south pole of Saturn's moon Enceladus were created by the gravity of the ring planet. The researchers report to Doug Hemingway of the Carnegie Institution in Washington in the British journal Nature Astronomy. The scientists studied the physics behind the pattern of the ice fund.

Enceladus orbits Saturn in an elliptical orbit. As a result, he is the ring planet a little closer and a little further away. As a result, the gravity of the gas giant, which changes as a result, causes the Trabant to be regularly kneaded in its orbit. This prevents the ice-covered moon from completely freezing: Under Enceladu's kilometer-thick ice sheet, therefore, spills an underground ocean.

"The stripes first observed by the Cassini mission are unique in our solar system," explains Hemingway. "They run parallel and evenly apart, about 130 kilometers long and 35 kilometers apart." The strips are fractures in the ice sheet, from which water from the subterranean ocean is continuously penetrating. "No other ice planet or moons have that kind of thing," says Hemingway.

Space Science Institute / JPL-Cal / DPA

Cracks on ice moon Enceladus: egg

The fact that the cracks were created at the South Pole, according to research, is due to the fact that the gravitational force of Saturn has the strongest effect on this region. Due to the changing gravity and the constant thawing and freezing of the water, the ice sheet is thinnest there.

Pressure causes ice sheets to break

In detail, the stripes have been created: While the moon has cooled on its orbit around Saturn, a part of the subterranean ocean is frozen. The water has expanded, the pressure in the ice has risen, so that the ice sheet has given way at the pole. A crack has emerged that looks remotely like a strip on the surface, the researchers report.

Over the first resulting ice column, new ocean water then reached the Enceladus surface and again increased the pressure in the ice sheet when freezing again. "That's why the ice sheet bent so badly that it broke another 35 kilometers away," says co-author Max Rudolph of the University of California at Davis. "Our model explains the regular removal of fractures."

The changing gravity of Saturn finally ensure that the crevices at the South Pole not freeze again, the researchers continue. Regular kneading only extend and narrow the columns. From space they are so permanently recognizable as a tiger pattern.