It is thought this could lead to an easier study of the moon's ocean
Astronomers at NASA have found what may be water vapour plumes erupting off the surface of Jupiter's moon, Europa.
NASA says this finding, from the Hubble Space Telescope, bolsters other observations.
It says this increases the possibility that missions to Europa may be able to sample its ocean without having to drill through miles of ice.
The plumes are estimated to rise about 125 miles before, presumably, raining material back down onto Europa's surface.
Europa has a huge global ocean, containing twice as much water as Earth's oceans, but it is protected by a layer of extremely cold and hard ice of unknown thickness.
"The plumes provide a tantalising opportunity to gather samples originating from under the surface without having to land or drill through the ice", NASA says.
"Europa's ocean is considered to be one of the most promising places that could potentially harbour life in the solar system," says Geoff Yoder, acting associate administrator for NASA's Science Mission Directorate in Washington.
"These plumes, if they do indeed exist, may provide another way to sample Europa's subsurface."
The team observed these finger-like projections while viewing Europa's limb as the moon passed in front of Jupiter.
"The atmosphere of an extrasolar planet blocks some of the starlight that is behind it," team leader William Sparks explains.
"If there is a thin atmosphere around Europa, it has the potential to block some of the light of Jupiter, and we could see it as a silhouette.
"And so we were looking for absorption features around the limb of Europa as it transited the smooth face of Jupiter."
In 10 separate occurrences spanning 15 months, the team observed Europa passing in front of Jupiter. They saw what could be plumes erupting on three of these occasions.
If confirmed, Europa would be the second moon in the solar system known to have water vapour plumes.
In 2005, NASA's Cassini orbiter detected jets of water vapour and dust spewing off the surface of Saturn's moon Enceladus.
Scientists may use the infrared vision of NASA's James Webb Space Telescope to confirm venting or plume activity on Europa.
NASA says it is also is formulating a mission to Europa - with a payload that could confirm the presence of plumes and study them from close range during multiple flybys.
The work by Sparks and his team will be published in the September 29th issue of the Astrophysical Journal.