The US space agency said Monday its telescope had detected water jets shooting up from Europa's southern polar region, where a salty body of water is believed to be hidden beneath the icy surface.

NASA said the plumes appeared to spurt as high as 200 kilometers (125 miles) before raining back down on the moon's crust. They were observed on three separate occasions in 2014.

Europa, one of more than 50 moons circling Jupiter, is considered one of the top places to search for life in the solar system because of its ocean, which contains twice as much water as all of Earth's seas combined.

Scientists say their discovery means they could potentially test samples taken from the water plumes to find out more about the ocean, rather than having to break through the moon's hard, icy crust.

"If the plumes are real, it potentially gives us easier access to the ocean below," lead researcher Williams Sparks of the Space Telescope Science Institute in Baltimore told reporters. This would allow them to "to search for signs of life in the ocean of Europa without needing to drill through miles of ice," he added.

More study needed

Sparks cautioned, however, that more evidence was needed before scientists could confirm the water plumes' existence. Hubble also detected water vapor on Europa in 2012, but follow-up observations showed no signs further of activity.

Paul Hertz, director of NASA's astrophysics division, said scientists had a special interest in places in the solar system, like Europa, that shared certain life-supporting characteristics with Earth.

NASA last year announced plans to send a robotic spacecraft to make more than 40 close flybys of the moon in the 2020s and possibly sample material in any plumes shooting out from its surface. It said the mission would aim to measure the habitability of Europa to see if conditions exist that could sustain living organisms.

Europa orbits Jupiter every three and a half days, and is only slightly smaller than Earth's moon. Only one other moon in the solar system - Saturn's Enceladus - has been confirmed to have water plumes.

nm/rc (Reuters, AFP, AP)