Recent astronomical news includes the arrival of the Dawn unmanned mission to the dwarf planet Ceres. Since its launch in 2007, the probe has relied on an innovative ion propulsion system rather than rockets.
With a diameter of roughly 590 miles, Ceres is the largest celestial body in the asteroid belt, which is located between the orbits of Mars and Jupiter. Dawn also visited the protoplanet Vesta, which is the second-largest body in the belt.
Scientists exploring Ceres have already found a mystery: the existence of bright spots on its surface. In one visible-light photograph, two white dots lie within a large crater. Not only is the origin of the spots unknown, but one appears cooler than the surrounding surface and another vanishes when imaged in thermal wavelengths.
Researchers have speculated that the spots may be made of ice or water existing inside minerals. However, Ceres is considered too close to the Sun to have so-called stable ice.