The 14-year mystery behind the water on the planet Saturn is now solved. Researchers have found that the planet's sixth largest moon named Enceladus is the source of a huge halo of water steam around Saturn.

The planet known for its spectacular rings is the only one of its kind found till now whose own moon showers rain water onto it on a regular basis. According to scientists, this is an activity unique to Saturn. When it comes to Earth, "no significant quantities of water enter our atmosphere from space."

Icy moon Enceladus

Enceladus, the sixth largest moon of the planet Saturn, has an active interior. However, its surface is cold and icy, mainly at its south pole. According to researchers, this is the region where geothermal activity is concentrated at four trenches that are dubbed "tiger stripes." It's these jets from which Enceladus throws approximately 550 pounds (250 kilograms) of water vapor every second.

Researchers said that the thrown out water from the icy moon forms a doughnut-shaped ring of water vapor around Saturn that almost equals to five Saturns in width and about as thick as one-half a Sat­urn.

Since the water vapor is translucent to visible light, it has not been detected until now, despite its huge size. However, the European Space Agency's Herschel space observatory, tuned to infrared wavelengths and succeeded in unveiling the mystery.

Researchers said that a large amount of Enceladus's rain water either gets lost in space, freezes on Saturn's rings, or perhaps falls onto other moons of the ringed planet, but what does remain to reach Saturn is enough to explain the source of the water found in its upper atmosphere.

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Enceladus
At least four distinct plumes of water ice spew out from the south polar region of Saturn's moon Enceladus. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Dec. 25, 2009. NASA/JPL/Space Science Institu
Enceladus
A stunning mosaic of the geologically active Enceladus after a Cassini flyby. Credit: NASA/JPL/Space Science
Enceladus
Heat radiating from the entire length of 95-mile (150-km) long fractures is seen in this best-yet heat map of the active south polar region of Saturn's ice moon Enceladus. Credit: NASA/JPL/GSFC/SwRI/SSI
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Skeet shoot at Enceladus. This image is the fourth skeet-shoot footprint taken during Cassini's very close flyby of Enceladus on Aug. 11, 2008. NASA/JPL/Space Science Institu
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Dramatic plumes, both large and small, spray water ice out from many locations along the famed "tiger stripes" near the south pole of Saturn's moon Enceladus in this image taken by NASA’s Cassini probe on Nov. 21, 2009. NASA/JPL/Space Science Institu
Enceladus
False color Cassini image illustrating the jets of fine icy particles erupting from the south polar region of Enceladus. Please Cassini Imaging Team and NASA/
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