Scientists have found definitive proof of water vapor on the largest object in the asteroid belt between the orbits of Mars and Jupiter. Ceres is considered a dwarf planet which means that it is larger than an asteroid, but smaller than a planet. It is roughly 590 miles in diameter and makes up 1/3 of the mass of the asteroid belt.

Using the European Space Agency’s Herschel space observatory astronomers have detected plumes of water vapor which erupt when the surface of Ceres warms slightly. Scientists believe that the dwarf planet has a rock core, but the amount of water on Ceres is believed to be greater than the amount of fresh water on Earth.

“This is the first time water vapor has been unequivocally detected on Ceres or any other object in the asteroid belt and provides proof that Ceres has an icy surface and an atmosphere,” said Michael Küppers of ESA in Spain, lead author of a paper in the journal Nature.

The discovery came at just the right time. NASA’s spacecraft Dawn just spent a year orbiting the astroid Vesta and is now on its way to Ceres. It is scheduled to arrive in the spring of 2015 and will be able to take an up close look at the surface of the dwarf planet.

“We’ve got a spacecraft on the way to Ceres, so we don’t have to wait long before getting more context on this intriguing result, right from the source itself,” said Carol Raymond, the deputy principal investigator for Dawn at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif. “Dawn will map the geology and chemistry of the surface in high-resolution, revealing the processes that drive the outgassing activity.”

Despite its icy surface, Ceres is believed to have some warmth below the surface. This has caused some, including NBC and Forbes, to speculate about the possibility of simple life forms beneath the surface. Further information should be provided when the Dawn spacecraft arrives.

The full findings of Michael Küppers and his associates were published in the journal Nature.

Source: NASA