Dawn probe sees Ceres' spots in more detail

Mission scientists still do not have an explanation for the spots

The US space agency has released a new picture of the brightest spots on the dwarf planet Ceres.

Nasa's Dawn probe has just retuned the image - one of the first snapshots to come down from the satellite since getting into its latest mapping orbit, which is now just 4,000km above the surface.

Mission scientists confess still to being puzzled by the features.

The best guess is that their brightness stems from the presence of ice or salt.

The spots sit in a crater that is about 90km wide.

"The bright spots in this configuration make Ceres unique from anything we've seen before in the Solar System," said Dawn principal investigator Chris Russell

"The science team is working to understand their source. Reflection from ice is the leading candidate in my mind, but the team continues to consider alternate possibilities, such as salt.

"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," the University of California, Los Angeles, researcher explained in a Nasa statement.

Ceres has a number of very bright surface features, but the pictured cluster is the standout example and has drawn most interest.

The Dawn mission arrived at the dwarf, which is located in the asteroid belt between Mars and Jupiter, in March.

It is due to spend at least the next year mapping the 950km-wide world, characterising its geology and composition.

Scientists regard Ceres as an object that set out on the path to becoming a big planet like Earth and Mars, but whose growth got to a certain point and then stalled.

The hope is that it will reveal information about the conditions that held sway in the early Solar System.

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