DEEPENING MYSTERY of BRIGHT LIGHTS on dwarf world Ceres
Spotty planetlet probed by NASA craft
NASA's Dawn space probe has completed its first mapping orbit of the dwarf planet Ceres and the bright spots spotted on the surface are much more numerous than first thought.
In March, as Dawn approached the planet, scientists spotted a bright spot on the surface of Ceres and more appeared as the spacecraft approached. A new animation of Dawn's first mapping orbit, 8,400 miles (13,600km) up, shows that the surface of the dwarf planet is dappled with shiny spots.
"Dawn scientists can now conclude that the intense brightness of these spots is due to the reflection of sunlight by highly reflective material on the surface, possibly ice," said Christopher Russell, principal investigator for the Dawn mission from the University of California, Los Angeles.
That will come as a letdown for those hoping to find alien civilizations on the surface of Ceres, but makes a lot of sense from an astronomical perspective. Ceres hangs out in the asteroid belt – indeed, it makes up about a third of the belt's estimated total mass – and the dwarf planet may have picked up its ice from the impacts of water-rich asteroids on its surface.
The Dawn spacecraft has now fired up its ion drive and is shifting its orbit closer to the surface of Ceres. The probe will swoop down as low as 2,700 miles (4,400km) from the surface and provide much more detail about Ceres' geology and what lies underneath, and take twice as many images as it did in its first mapping pass.
Come August it will go even lower, and within a few months NASA should have a detailed map of the object's entire, lumpy surface area. Then in December the probe will make its closest approach yet, heading just 233 miles (375km) above the surface to examine new points of interest. ®