Dr Ballard of the University of Washington was speaking to PRI . She said exomoons could be the 'predominant sites of life in the universe ' Many planets discovered outside the solar system are Jupiter-sized worlds . It suggests habitable Earth-like planets may not be that common . Instead , moons orbiting larger planets could be the best bet for life .
Dr Sarah Ballard of the University of Washington was speaking to PRI . She said exomoons could be the 'predominant sites of life in the universe ' Many planets discovered outside the solar system are Jupiter-sized worlds . It suggests habitable Earth-like planets may not be that common . Instead , moons orbiting larger planets could be the best bet for life .