( CNN ) They may not be `` Star Trek '' -type extraterrestrials , but we may be close to finding evidence of alien life , a NASA scientist says . `` I think we 're going to have strong indications of life beyond Earth within a decade , and I think we 're going to have definitive evidence within 20 to 30 years , '' NASA chief scientist Ellen Stofan said Tuesday during a panel discussion on water in the universe . `` We know where to look . We know how to look , '' she said . `` In most cases , we have the technology , and we 're on a path to implementing it . And so I think we 're definitely on the road . '' NASA released a graphic noting that scientists have found evidence or indications of water on a number of celestial bodies , including the dwarf planet Ceres and Jupiter 's moon Europa . The Hubble Space Telescope has been key to the discoveries , NASA said in a news release . `` Scientists using NASA 's Hubble Space Telescope recently provided powerful evidence that ( Jupiter 's moon ) Ganymede has a saltwater , sub-surface ocean , likely sandwiched between two layers of ice , '' the agency noted . There are some caveats involved , of course . NASA is n't talking about intelligent alien civilizations from the Alpha Quadrant ; it 's referring to microorganisms . `` We are not talking about little green men , '' Stofan said at the panel . `` We are talking about little microbes . '' Still , former astronaut John Grunsfeld said it 's an exciting time -- and he thinks it 's just a matter of time before we find life outside our solar system as well . `` I think we 're one generation away in our solar system , whether it 's on an icy moon or on Mars , and one generation on a planet around a nearby star , '' he said . And , he added , who knows what that life will look like ? `` Once we get out beyond Mars , the likelihood that it 's similar to Earth because we share that material gets very , very low , '' he said . `` And I think that 's where it starts getting exceptionally exciting . ''
• chief scientist Ellen ##son believes we 're close to finding alien bodies . Indications within a decade ; definitive ##s within ` ` 20 to 30 years , '' she said . Finding information on other celestial bodies is key to determination .