NASA's chief scientist predicted Tuesday that alien life will be discovered by 2025.
Ellen Stofan made the prediction while discussing the agency's plan to explore potentially habitable planetary bodies and extraterrestrial life.
"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," she said during a panel discussion at NASA's headquarters in Washington DC.
"We know where to look. We know how to look. 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's Kepler space telescope found that most stars have planets, and scientists believe that some may be habitable.
Space exploration has found oceans below Jupiter's Europa and Ganymede moons, and Saturn's Enceladus moon. Some researchers believe that water may flow on Mars, and NASA's Curiosity rover discovered molecules containing carbon and nitrogen on the planet. The discoveries suggest that they could sustain life.
Former astronaut and associate administrator for NASA's Science Mission Directorate, John Grunsfeld, agreed that finding aliens is not a fantasy.
"I think we're one generation away in our solar system, whether it's on an icy moon or on Mars, and one generation [away] on a planet around a nearby star," he predicted.
A new Mars rover will launch in 2020 with the goal of finding evidence of past life. Astronauts on Mars may be a reality in 15-25 years - a triumph that Stofan said is critical.
"...I have a bias that it's eventually going to take humans on the surface of Mars — field geologists, astrobiologists, chemists — actually out there looking for that good evidence of life that we can bring back to Earth for all the scientists to argue about," she said.