Scientists decoded the reason behind the ‘tiger stripes’ on Enceladus, a moon of Saturn which has a liquid ocean under its icy surface. The ‘tiger stripes’, first seen by the Cassini mission to Saturn, are considered as partially open fissures that connect to the liquid water ocean beneath the ice shell.
The researchers, in a paper published in nature astronomy, proposed that “secular cooling” leads to a thickening of the ice shell and building of global tensile stresses which caused the first fracture to form at one of the poles. They examined the reason behind the presence of those stripes only on the moon’s south pole. The other intriguing nature of the stripes is that they are evenly spaced.
“To date, no study simultaneously explains why the tiger stripes should be located only at the south pole, why there are multiple approximately parallel and regularly spaced fractures, what accounts for their spacing of about 35 km, and why similarly active fissures have not been observed on other icy bodies,” the research paper stated.
The team of researchers came to a conclusion that the fissures could have formed at either pole, relieving the stresses and preventing similar fissure at the opposite pole, but the south pole just happened to split open first.
“The steadily erupting water ice loads the flanks of the open fissure, causing bending in the surrounding elastic plate and further tensile failure in bands parallel to the first fracture - a process that may be unique to Enceladus, where the gravity is too weak for compressive stresses to prevent fracture propagation through the thin ice shell,” the research added.
According to the researchers, the Baghdad fissures, named after cities mentioned in Arabian Nights, was the first to form. The fissure allowed the ocean water to spew which led to three more parallel cracks. The jets of water under the ocean surface froze and fell back which added to a new form of pressure causing additional splits.