Saturn’s moon Enceladus is best known for its jet geysers shooting water and other material high above its surface. It turns out, the geysers might just be an optical illusion.
New research suggests most of these eruptions are not geysers, but rather “diffuse curtains.”
What we see as individual geysers shooting water into the area could just be phantoms.
“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 of the study and a participating scientist on the Cassini mission. “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.”
Spitale and his colleagues were particularly interested in the faint background glow in the Cassini images of the eruptions on Enceladus.
The researchers said the jets, “look to them to be superimposed intermittently upon this background structure.”
How would this illusion work? The researchers modeled the jets on Enceladus as uniform curtains along the tiger stripe fractures on the surface. The two big, bright areas you see in the image above? Those appear in places where we are looking through a “fold” in the curtain.
“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.”
The video below does a good job illustrating this illusion in action.
What does this mean for Enceladus?
Water and other materials are still erupting. It just may not be in the form of geyser jets like scientists thought.
NASA describes what curtain eruptions look like on Earth:
Curtain eruptions occur on Earth where molten rock, or magma, gushes out of a deep fracture. These eruptions, which often create spectacular curtains of fire, are seen in places such as Hawaii, Iceland and the Galapagos Islands.
What has Cassini been up to?
Besides helping us learn more about Enceladus, Cassini has been snapping incredible pictures of Saturn and its surrounding moons.
Mimas’ (one of Saturn’s moons) eye-shaped feature is easy to spot in the above image. That’s an 80 mile-wide impact crater called Herschel.
Here we see Saturn’s dynamic weather system in action.
The many rings of Saturn. The thicker rings in the bottom half are Saturn’s C rings. Saturn’s D rings appear much fainter in the top half of the image.