Saturn's Enceladus moon hides 'great lake' of water
3 April 2014 Last updated at 22:58 BST
The evidence for an ocean of water under the surface of one of Saturn's moons is overwhelming, according to scientists at NASA and the European Space Agency.
They say it underlines the possibility of finding microbial life elsewhere in our solar system.
The next step is to send spacecraft to investigate further, as BBC science correspondent Pallab Ghosh reports.