Better detail and imagery on those bright spots on Ceres, great images: (scroll down if you first don't see the article)
http://www.vox.com/2016/3/23/1129256...s-bright-spots
From above link:
Now they've gotten an even closer look. On Tuesday, NASA released the most detailed images yet from Dawn — taken just 240 miles above the surface. Here is Occator Crater, which contains the brightest of the bright spots:
The bright central spots near the center of Occator Crater are shown in enhanced color in this view from NASA's Dawn spacecraft. Such views can be used to highlight subtle color differences on Ceres's surface.
The crater is 57 miles across and 2.5 miles deep. "The latest images," NASA announced, "taken from 240 miles above the surface of Ceres, reveal a dome — with fractures crisscrossing the top and flanks — in a smooth-walled pit in the bright center of the crater."
The still-mysterious origins of Ceres's shiny dots
So why is the crater shiny? In a paper published last December in Nature, scientists argued that the reflection may come from a magnesium sulfate called hexahydrite.
The idea is that Ceres has a salty layer of water ice just beneath its surface. At some point in the past, asteroids pummeled the dwarf planet, bringing that mixture to the surface. The water ice then evaporated away in the sun, leaving only the bright-colored hexahydrite behind. And because the rest of the planet is so dark, those bright spots stick out.
Still, this needs further exploration. The existence of subsurface water ice remains one of the central mysteries of Ceres.
Until the Dawn mission arrived in 2015, scientists had never seen Ceres up close. The dwarf planet, a 590-mile-wide ball of rock and ice that lies in the asteroid belt, was the biggest unexplored rock between the sun and Pluto.
Scientists have long wondered — based on measurements of the dwarf planet's mass — if Ceres might have vast amounts of ice in its mantle. Some speculated there might be as much fresh water locked away there as is present on all of Earth.
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