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.
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.
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.
As the Dawn spacecraft settles into lower orbits around Ceres the photos of this small world are of ever better resolution. The mysterious bright spots have slowly resolved into an interesting arrangement of multiple spots. Despite many wild claims on YouTube and UFO websites of alien cities or crashed spacecraft, the spots are looking more and more like a set of ice outcroppings. They are still fascinating, if just a bit more ordinary than some would hope.
NASA’s Dawn mission captured a sequence of images, taken for navigation purposes, of dwarf planet Ceres on May 16, 2015. The image showcases the group of the brightest spots on Ceres, which continue to mystify scientists. It was taken from a distance of 4,500 miles (7,200 kilometers) and has a resolution of 2,250 feet (700 meters) per pixel.
“Dawn scientists can now conclude that the intense brightness of these spots is due to the reflection of sunlight by highly reflective material on the surface, possibly ice,” Christopher Russell, principal investigator for the Dawn mission from the University of California, Los Angeles, said recently.
Dawn arrived at Ceres on March 6, marking the first time a spacecraft has orbited a dwarf planet. Previously, the spacecraft explored giant asteroid Vesta for 14 months from 2011 to 2012. Dawn has the distinction of being the only spacecraft to orbit two extraterrestrial targets.
The spacecraft has been using its ion propulsion system to maneuver to its second mapping orbit at Ceres, which it will reach on June 6. The spacecraft will remain at a distance of 2,700 miles (4,400 kilometers) from the dwarf planet until June 30. Afterward, it will make its way to lower orbits.
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.
The bright dot on Ceres has the UFO community all a twitter.
As the Dawn probe approaches Ceres each day brings ever higher resolution photos. The bright dot first showed up as a large white blotch on the disk. Not a huge surprise, even Earth based images showed areas of the dwarf planet were much brighter.
As the spacecraft neared the dot has been revealed to be quite small. Indeed the images are quite intriguing, a very bright dot with a smaller dot directly beside it. The two features are near the center of a fairly large impact crater.
Of course the images are intriguing. Whenever something this odd shows up in a NASA mission image there is a group of folks who go off the rails entirely, the UFO/alien community. I looked at the image and went “Hmmmm?”. Then as I sat for a moment I wondered what the UFO websites were saying about this photo. A quick sampling showed that the UFO/alien community has let speculation run rampant.
The articles and YouTube videos are popping up, fueled by the latest Dawn mission image releases… It is an alien city, a giant spacecraft, and, of course Ceres is a fragment of the destroyed planet Phaeton. After the buzz about the UFO in orbit around asteroid 2004 BL86 the UFO community is ready for something new. Even the British newspaper The Daily Mail has let this “alien” speculation seep into its reporting.
The planetary science community has a more likely theory for the dot, a cryo-volcano. It is known that Ceres harbors a great deal of water. A vent of some sort allowing water to escape into space from a subsurface deposit is not that unlikely. The process would not be that dissimilar to what we have observed on comets. The location of the feature at the center of an impact crater is also interesting. Note that there is another light colored feature at the center of another impact crater on the lower left of the latest image. An older, less active or dormant cryo-volcano?
When looking at the image you have to remember that the surface of most asteroids and comets is actually quite dark, about the same as charcoal. Ceres has a v-band albedo of 0.09, thus only 9% of the sunlight is reflected by the surface. Anything bright white, like fresh ice, is going to be stunningly bright in comparison.
When Dawn arrives at Ceres and settles into orbit we will have our answers, the images should show the phenomena in exquisite detail. We just have to wait a few months. It would be totally cool if the bright dot did turn out to be some sort of alien artifact. But I have to agree with the mission team, it is probably some form of cryo-volcano, also cool.