dwarf planet – A Darker View

Ceres Up Close

Dawn has been in orbit around Ceres for over a year now, having entered orbit back on March 6th, 2015. Most of the dwarf planet has been photographed and mapped in high resolution now, creating beautiful imagery that reveals a great deal of interesting terrian. As we have seen with other dwarf planets like Pluto, these little worlds are surprisingly dynamic places, hardly the dead rocks one might have expected.

The bright features in Occator crater have been revealed to be some sort of cryovolcano. While not certain, the bright is likely to be water ice, or perhaps a briny, salt and water mixture. There has even been some evidence of vapor observed over the crater, possibly from sublimating ices.

I am sure this is a large disappointment to those who claimed it was some sort of alien base. Not that this has stopped the claims, they are just more modest in size. You can find YouTube videos of folks combing through the high resolution images and claiming any little feature that is slightly regular looking is some alien artifact.

More enjoyable to watch is a JPL video pointing out the highlights of Ceres…

New Clues to Ceres’ Bright Spots and Origins

NASA/JPL press release…

Ceres reveals some of its well-kept secrets in two new studies in the journal Nature, thanks to data from NASA’s Dawn spacecraft. They include highly anticipated insights about mysterious bright features found all over the dwarf planet’s surface.

Ceres Spots — This false color image from NASA’s Dawn spacecraft of Ceres’ Occator Crater shows differences in surface composition.
Credit: NASA/JPL

In one study, scientists identify this bright material as a kind of salt. The second study suggests the detection of ammonia-rich clays, raising questions about how Ceres formed.

About the Bright Spots

Ceres has more than 130 bright areas, and most of them are associated with impact craters. Study authors, led by Andreas Nathues at Max Planck Institute for Solar System Research, Göttingen, Germany, write that the bright material is consistent with a type of magnesium sulfate called hexahydrite. A different type of magnesium sulfate is familiar on Earth as Epsom salt.

Nathues and colleagues, using images from Dawn’s framing camera, suggest that these salt-rich areas were left behind when water-ice sublimated in the past. Impacts from asteroids would have unearthed the mixture of ice and salt, they say.

“The global nature of Ceres’ bright spots suggests that this world has a subsurface layer that contains briny water-ice,” Nathues said.

A New Look at Occator

The surface of Ceres, whose average diameter is 584 miles (940 kilometers), is generally dark — similar in brightness to fresh asphalt — study authors wrote. The bright patches that pepper the surface represent a large range of brightness, with the brightest areas reflecting about 50 percent of sunlight shining on the area. But there has not been unambiguous detection of water ice on Ceres; higher-resolution data are needed to settle this question.

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The Dawn Mission Nears Ceres

JPL press release…

NASA’s Dawn spacecraft has returned new images captured on approach to its historic orbit insertion at the dwarf planet Ceres. Dawn will be the first mission to successfully visit a dwarf planet when it enters orbit around Ceres on Friday, March 6.

“Dawn is about to make history,” said Robert Mase, project manager for the Dawn mission at NASA’s Jet Propulsion Laboratory in Pasadena, California. “Our team is ready and eager to find out what Ceres has in store for us.”

Recent images show numerous craters and unusual bright spots that scientists believe tell how Ceres, the first object discovered in our solar system’s asteroid belt, formed and whether its surface is changing. As the spacecraft spirals into closer and closer orbits around the dwarf planet, researchers will be looking for signs that these strange features are changing, which would suggest current geological activity.

“Studying Ceres allows us to do historical research in space, opening a window into the earliest chapter in the history of our solar system,” said Jim Green, director of NASA’s Planetary Science Division at the agency’s Headquarters in Washington. “Data returned from Dawn could contribute significant breakthroughs in our understanding of how the solar system formed.”

Dawn began its final approach phase toward Ceres in December. The spacecraft has taken several optical navigation images and made two rotation characterizations, allowing Ceres to be observed through its full nine-hour rotation. Since Jan. 25, Dawn has been delivering the highest-resolution images of Ceres ever captured, and they will continue to improve in quality as the spacecraft approaches.

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