Scientists have long thought that the dwarf planet Ceres might hold some form of water, but they've only had indirect evidence at best -- until today, that is. An ESA-led team has used signal fluctiations to confirm that the asteroid belt planetoid is spewing water vapor from two points on its surface, creating both ice and a rudimentary atmosphere. It isn't clear what's producing the vapor, although researchers believe that geysers, thawing or icy volcanoes may be responsible. Whatever is behind Ceres' behavior, the discovery could improve our understanding of how water reached Earth. We'll get a much clearer picture of what's happening in early 2015, when NASA's Dawn probe swings by to map the mini-planet's water activity in greater detail.

[Image credit: ESA/ATG medialab/Küppers et al.]