Washington, Sep 27 (IANS) Nasa on Monday released further evidence to show that there may be oceans on Europa -- Jupiter's largest moon.

Releasing new images captured from the Hubble Space Telescope, the space research organisation announced "surprising evidence of activity" on Europa which could be water vapour erupting from the icy moon, the telegraph reported.

Hubble made its latest identification by studying Europa as it passed in front of Jupiter.

The telescope looked in ultraviolet wavelengths to see if the giant planet's light was in any way being absorbed by material emanating from the moon's surface.

Ten times Hubble looked and on three of those occasions it spied what appeared to be "dark fingers" extending from the edge of Europa.

William Sparks, the lead astronomer on the study, said he could think of no natural phenomenon other than water plumes that might produce such protuberances.

"We're not aware of any instrumental artefacts that could cause these features; they are statistically significant. But we remain cautious because we are working at difficult wavelengths for Hubble," the BBC quoted him as saying.

"We do not claim to have proven the existence of plumes, but rather to have contributed evidence that such activity may be present."

Nonetheless, the location for the putative jets looks very similar to the region where Hubble earlier this decade detected an excess of oxygen and hydrogen -- the component parts of water, the BBC reported.

Europa is one of the largest of Jupiter's 67 known moons. In late 2013 the Hubble telescope observed water vapour erupting from Europa, in what was hailed as a ‘tremendously exciting' discovery.

Previous scientific findings had already pointed to the existence of an ocean located under Europa's icy crust, but it was thought teams in the future would have to drill through the thick layer of ice before any signs of life would be detectable.

Lorenz Roth of Southwest Research Institute in San Antonio said at the time that if the plumes of vapour were connected to the ocean beneath the crust they could start searching for life nearer the surface.

"This means that future investigations can directly investigate the chemical makeup of Europa's potentially habitable environment without drilling through layers of ice," the telegraph quoted him as saying.

"And that is tremendously exciting."

Participants in the teleconference included Paul Hertz, director of NASA's Astrophysics Division; William Sparks of the Space Telescope Science Institute in Baltimore; Britney Schmidt of the Georgia Institute of Technology; and Jennifer Wiseman, senior Hubble project scientist at NASA's Goddard Space Flight Centre.