Although NASA's Dawn mission is now carrying out its second mapping orbit of dwarf planet Ceres, beaming back the highest resolution images of the small world's surface to date, we're still none the wiser as to what those weird bright patches are.
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"The bright spots in this configuration make Ceres unique from anything we've seen before in the solar system," said Chris Russell, principal investigator for the mission at the University of California, Los Angeles. "The science team is working to understand their source."
The blobs, which quickly shot to the headlines shortly before Dawn arrived in Ceres orbit in March, have kept their true nature secret. Although planetary physicists have some ideas as to what they may be, these white patches are becoming quite a mystery.
"Reflection from ice is the leading candidate in my mind, but the team continues to consider alternate possibilities, such as salt," added Russell in Wednesday's NASA news release. "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."
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Although their nature is not currently known, these newest observations - from 2,700 miles (4,400 kilometers) above Ceres - are among the first from the second mapping orbit. The mission will remain at this altitude until June 28, when it will drop even closer to the dwarf planet. By early August, Dawn will be taking observations only 900 miles (1,450 kilometers) from the surface.
From this high-resolution look into the 55-mile (90-kilometer)-wide crater containing the bright patches, it is becoming clear that rather than being two amorphous blobs, there is some fine-scale structure - many individual white patches around a central cluster in two locations. And so far, without knowledge as to what they are, explanations for this fine-scale structure will not be forthcoming for some time.
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But help is at hand; Dawn's visible and infrared mapping spectrometer (VIR) will be used to gauge the bright patches' temperature, which may prove critical to unraveling this enduring Cererian conundrum.
What do YOU think these bright spots could be? NASA would love to know!