Astronomers using the James Webb Space Telescope (JWST) have spotted an enormous jet of water spewing out of Saturn’s moon Enceladus. We knew that Enceladus has a liquid water ocean beneath its icy crust that occasionally leaks out, but this jet is far larger than any that has been seen before.
Enceladus is only about 500 kilometres across, and previous plumes of water vapour that have been spotted there have sprayed hundreds of kilometres from the surface. This new plume measures more than 9600 kilometres long – more than the entire length of Africa, or nearly three times the diameter of Earth’s moon.
“When I was looking at the data, at first, I was thinking I had to be wrong. It was just so shocking to detect a water plume more than 20 times the size of the moon,” said Geronimo Villanueva at NASA’s Goddard Space Flight Center in Maryland in a statement.
Villanueva and his colleagues found that water is cascading out of Enceladus at an extraordinary rate of about 300 litres per second. As the icy moon circles Saturn, the researchers found that about 30 per cent of the leaked water ends up in a ring-shaped structure, which shares its orbit with Saturn’s outermost ring. The rest of the water vapour floats away and settles elsewhere in the Saturn system.
“The orbit of Enceladus around Saturn is relatively quick, just 33 hours. As it whips around Saturn, the moon and its jets are basically spitting off water, leaving a halo, almost like a donut, in its wake,” said Villanueva. “In the Webb observations, not only was the plume huge, but there was just water absolutely everywhere.”
Enceladus’s liquid water ocean makes it one of the most promising places in the solar system to search for the possibility of alien life. Studying plumes like this one could help researchers understand the composition and dynamics of that ocean, and JWST will continue looking at this astonishing little moon in the years to come.