Many features that appear to be individual jets of material erupting along the length of prominent fractures in the moon’s south polar region might be phantoms created by an optical illusion, according to the new study.
In analyzing Cassini’s images of the eruptions on Enceladus, Spitale and colleagues took particular note of the faint background glow present in most images. The brightest eruption features, which appear to be discrete jets, look to them to be superimposed intermittently upon this background structure.
The researchers modeled eruptions on Enceladus 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 researchers think this optical illusion is responsible for most of what appear to be individual jets.