Ceres, which orbits the Sun in the asteroid belt between Mars and Jupiter, is a unique body in the Solar System, bearing many similarities to Jupiter’s moon Europa and Saturn’s moon Enceladus, both considered to be potential sources for harboring life. In March of 2015, NASA’s Dawn mission will arrive at the dwarf planet Ceres, the first of the smaller class of planets to be discovered and the closest to Earth. On Thursday, August 15, Britney Schmidt, science team liaison for the Dawn Mission, and Julie Castillo-Rogez, planetary scientist from JPL, spoke in an Google Plus Hangout titled ‘Ceres: Icy World Revealed?’ about the growing excitement related to the innermost icy body.
“I think of Ceres actually as a game changer in the Solar System,” Schmidt said. “Ceres is arguably the only one of its kind.”
When Ceres was discovered in 1801, astronomers first classified it as a planet. The massive body traveled between Mars and Jupiter, where scientists had mathematically predicted a planet should lie. Further observations revealed that a number of small bodies littered the region, and Ceres was downgraded to just another asteroid within the asteroid belt. It wasn’t until Pluto was classified as a dwarf planet in 2006 that Ceres was upgraded to the same level.
Ceres is the most massive body in the asteroid belt, and larger than some of the icy moons scientists consider ideal for hosting life. It is twice the size of Enceladus, Saturn’s geyser-spouting moon that may hide liquid water beneath its surface.
Unlike other asteroids, the Texas-sized Ceres has a perfectly rounded shape that hints toward its origins.
“The fact that Ceres is so round tells us that it almost certainly had to form in the early solar system,” Schmidt said. She explained that a later formation would have created a less rounded shape.
The shape of the dwarf planet, combined with its size and total mass, reveal a body of incredibly low density.
“Underneath this dusty, dirty, clay-type surface, we think that Ceres might be icy,” Schmidt said. “It could potentially have had an ocean at one point in its history.”
“The difference between Ceres and other icy bodies [in the Solar System] is that it’s the closest to the Sun,” Castillo-Rogez said.
Ceres --The Dwarf-Water Planet Unique in Our Solar System: NASA Asks "Could It Host Life?"
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