New research proposes the possibility that icy eruptions on the surface of Saturn’s moon Enceladus could be in the form of broad, curtain-like eruptions, rather than discrete jets.
Based on data obtained from NASA’s Cassini mission, the researchers say these eruptions from Saturn’s moon Enceladus might be diffuse curtains rather than discrete jets.
Though they appear to be individual jets of eruption along the length of prominent fractures in the moon’s south polar region, they might be phantoms created by an optical illusion, they said in their paper published in the journal Nature.
“We think most of the observed activity represents curtain eruptions from the ‘tiger stripe’ fractures, rather than intermittent geysers along them,” said Joseph Spitale, lead author and a scientist on the Cassini mission at the Planetary Science Institute in Tucson, Arizona. “Some prominent jets likely are what they appear to be, but most of the activity seen in the images can be explained without discrete jets.”
In Cassini’s images of the eruptions, they observed the faint background glow, the brightest eruption features, which appear to be discrete jets, as if they are superimposed intermittently. When they modeled eruptions as uniform curtains along the tiger stripe fractures, they found that phantom brightness enhancements appear in places where the viewer is looking through a “fold” in the curtain.
The folds appear because the fractures in Enceladus’ surface are more wavy, leading the researchers to consider it an optical illusion. “The viewing direction plays an important role in where the phantom jets appear,” said Spitale. “If you rotated your perspective around Enceladus’ south pole, such jets would seem to appear and disappear.”
Similar curtain eruptions occur on Earth where molten rock, or magma, gushes out of a deep fracture and they often create curtains of fire in places such as Hawaii, Iceland and the Galapagos Islands.