On Tuesday, NASA officials announced that the 65-foot long Dawn spacecraft had captured the best ever photograph of the dwarf planet Ceres. Launched in September 2007, the probe's main mission is to research both Ceres and the dry, rocky protoplanet Vesta. Both reside within the confines of the asteroid belt between Mars and Jupiter. NASA explained in a press release that capturing the Ceres image represents "a new milestone for a spacecraft that soon will become the first human-made probe to visit a dwarf planet." To the untrained eye, the image might seem blurry and unfocused — but to an astronomer, it's a priceless treasure.
"At 43 pixels wide, the new images are more than 30 percent higher in resolution than those taken by NASA's Hubble Space Telescope in 2003 and 2004 at a distance of over 150 million miles," wrote NASA (yeah, that's a lot of space to cover). Because the probe is moving toward Ceres, unlike Hubble, which is essentially locked in place above the Earth, the opportunity for increasingly detailed imagery is boundless. The last time Dawn snapped a photo of the dwarf planet, it was just a tiny dot on a vast black canvas — now, it's starting to really look like something big.
Initial navigation images taken back on Jan. 13 showed a mysterious "white spot" on Ceres' surface, indicating that sunlight was being reflected off of something large — astronomers just weren't certain what that "something" was (although it probably wasn't a Transformer, sorry). Said Carol Raymond, deputy principal investigator of the Dawn mission at NASA's Jet Propulsion Laboratory (JPL):
We are already seeing areas and details on Ceres popping out that had not been seen before. For instance, there are several dark features in the southern hemisphere that might be craters within a region that is darker overall. Data from this mission will revolutionize our understanding of this unique body. Ceres is showing us tantalizing features that are whetting our appetite for the detailed exploration to come.
For the past 14 months, the Dawn spacecraft has been studying the protoplanet and sometimes-asteroid Vesta, which has also yielded some incredible footage and data. On Jan. 21, NASA announced that the probe had photographed a series of curved gullies on Vesta, indicating potential "short-lived flows of water-mobilized material on its surface." Jennifer Scully, postgraduate researcher at the University of California, Los Angeles, said:
Nobody expected to find evidence of water on Vesta. The surface is very cold and there is no atmosphere, so any water on the surface evaporates. However, Vesta is proving to be a very interesting and complex planetary body. We're not suggesting that there was a river-like flow of water. We're suggesting a process similar to debris flows, where a small amount of water mobilizes the sandy and rocky particles into a flow.
The Dawn spacecraft is slated to begin orbiting Ceres on March 6, at which point astronomers hope to finally uncover the mysteries surrounding the asteroid belt's largest object, such as the suspected presence of water beneath the planet's icy surface.
Jim Green, the planetary science division director at NASA Headquarters in Washington, said, "We know so little about our vast solar system, but thanks to economical missions like Dawn, those mysteries are being solved."