NASA’s Dawn spacecraft captured this image of Ceres and its mysterious bright spots on June 25, 2015, from a distance of 2,700 miles (4,400 km).
This image was taken by NASA’s Dawn spacecraft on June 25, 2015, from a distance of 2,700 miles (4,400 km). The image has a resolution of 450 feet (140 meters) per pixel. Image credit: NASA / JPL-Caltech / UCLA / MPS / DLR / IDA.
The intriguing bright spots on Ceres lie in the Occator crater. Occator is the name of the Roman agriculture deity of harrowing, a method of leveling soil.
The crater has a diameter of 60 miles (90 km) and a depth of two miles (4 km).
“The craters we find on Ceres, in terms of their depth and diameter, are very similar to what we see on Dione and Tethys, two icy satellites of Saturn that are about the same size and density as Ceres,” said Dawn science team member Paul Schenk, a geologist at the Lunar and Planetary Institute in Houston.
In examining the way Occator’s bright spots reflect light at different wavelengths, members of the Dawn science team have not found evidence that is consistent with ice.
The spots’ albedo is also lower than predictions for concentrations of ice at the surface.
“The science team is continuing to evaluate the data and discuss theories about these bright spots at Occator,” said Dr Chris Russell of the University of California, Los Angeles, Dawn’s principal investigator.
“We are now comparing the spots with the reflective properties of salt, but we are still puzzled by their source.”
This image is a close-up from the image above and shows the Occator crater with a cluster of mysterious bright spots. Image credit: NASA / JPL-Caltech / UCLA / MPS / DLR / IDA.
Dawn is around 900 miles (1,450 km) from Ceres. It is also 2.06 astronomical units (191 million miles, or 308 million km) from Earth, or 775 times as far as the Moon and 2.03 times as far as the Sun.
Radio signals, traveling at the universal limit of the speed of light, take 34 minutes to make the round trip.
Dawn is the first mission to visit a dwarf planet, and the first to orbit two distinct Solar System targets.
It orbited protoplanet Vesta for 14 months in 2011 and 2012, and arrived at Ceres on March 6, 2015.
