-Daniel aka Obsidian
NASA Gets Best View Yet of Mysterious Bright Spots on
Ceres
NASA's Dawn spacecraft obtained this
image of the brightest spots on dwarf planet Ceres on June 6, …
NASA's Dawn spacecraft has snapped
the best-ever images of the dwarf planet Ceres' bright spots, but the strange
features still have researchers scratching their heads.
The new photos resolve the' bright
spots on Ceres into numerous points of varying sizes. The brightest ones lie
within a crater about 55 miles (90 kilometers) wide, researchers said. You can
see a video tour of Ceres' strange white spots on
Space.com that shows how the odd features have come into focus for Dawn over
the last two months.
"The bright spots in this
configuration make Ceres unique from anything we've seen before in the solar
system. The science team is working to understand their source," Dawn
principal investigator Chris Russell of UCLA said in a statement.
"Reflection from ice is the leading candidate in my mind, but the team
continues to consider alternate possibilities, such as salt." [More Photos of the Dwarf Planet Ceres]
Dawn captured the images this month
from its second mapping orbit of Ceres, an orbit that lies about 2,700 miles
(4,400 km) above the surface of the heavily cratered world. But the probe will
soon get even closer to the dwarf planet — close enough, perhaps, to take the
bright spots' measure at last.
On June 28, Dawn will begin
spiraling down to an orbit with an altitude of 900 miles (1,450 km), finally
getting there in early August. (It takes Dawn a while to get around because the
probe is powered by superefficient but low-thrust ion engines.)
"With closer views from the new
orbit and multiple view angles, we soon will be better able to determine the
nature of this enigmatic phenomenon," Russell said in the same statement.
The $473 million Dawn mission
launched in September 2007 to study Ceres and Vesta, the two largest objects in
the main asteroid belt between Mars and Jupiter. Ceres is about 590 miles (950
km) wide, while Vesta's diameter is 330 miles (530 km).
Dawn orbited Vesta from July 2011
through September 2012, when it departed for Ceres. The spacecraft arrived at
Ceres this past March, in the process becoming the first probe ever to circle
two objects beyond the Earth-moon system, as well as the first to orbit a dwarf
planet.
The new images from Dawn's second
mapping orbit have helped highlight some of the differences between Ceres and
Vesta. For example, while both objects have been heavily pockmarked by craters,
Ceres bears more evidence of geological activity on its surface, such as flows
and landslides, NASA officials said.
Dawn is scheduled to continue
studying Ceres through June 2016. The probe will make its final observations of
the dwarf planet from an extremely close-in orbit, eyeing Ceres from just 230
miles (375 km) away.
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