Friday, 11 May 2012 12:54
May 11. 2012
Scientists affirmed this week that new data indicate what was believed to be a large asteroid is actually a tiny planet.
Using images collected by NASA's Dawn spacecraft, researchers said they were able to glean a more detailed look at Vesta, the second largest known asteroid. Overhauling their original hypothesis, scientists at the space agency said this week that the new information suggests Vesta's genesis occurred during the early stages of the development of the Solar System, likely within the first few millions of years.
Researchers asserted that Vesta has many of the characteristics associated with planets, including that its iron core may have spawned a magnetic field, albeit a fleeting one. Scientists noted that they still know relatively little about the planet's composition, though new images depict an alternating landscape of dark and bright patches, The New York Times reports.
Christopher Russell, a scientist at UCLA and the principal investigator of the Dawn mission, said that the spacecraft had unearthed a number of Vesta's secrets. Dawn's visible and infrared mapping spectrometer allowed researchers the chance to glimpse inside the protoplanet.
"Vesta looks like a little planet," Russell said. "It has a beautiful surface, much more varied and diverse than we expected. We knew Vesta's surface had some variation in color, but we did not expect the diversity that we see or the clarity of the colors and textures, or their distinct boundaries. We didn't find gold on Vesta, but it is still a gold mine."
Dawn has been orbiting Vesta since July 2011, according to NASA. Vesta is located in an asteroid belt between Mars and Jupiter, approximately 321 million miles away from Earth. According to Russell, the team had expected to find one giant crater on the protoplanet, but surprisingly discovered it was home to two. The smaller of the two measures roughly 321 miles, while the larger one is more than 380 miles in length. Russell asserted that they were both located in Vesta's southern region.
"One dates at about a billion years ago, and the other at least 2 billion years ago," he added. "Seeing two was a real discovery, and getting their ages is even better. The ages look like they correspond to the dates when we think rocks were blasted off Vesta; some came all the way to Earth. The large size of the craters can easily account for the material that came off, to fall as meteorites and many smaller 'Vestoids' that are like very large boulders."
Additionally, the scientists said that they had discovered Vesta is home to large mountain ranges. The tallest such land mass is more than twice the height of Mount Everest, according to the team of researchers, and likely formed in the wake of a major impact to the protoplanet's surface.
Dawn's ability to capture such detailed data about Vesta is a result of the sophisticated engineering tools with which the spacecraft is equipped. Dawn has relayed nuanced information about Vesta's mineral composition, among other characteristics, collecting data in different wavelengths of radiation. Russell described the planet as looking "like an artist has painted the craters in fancy patterns," affirming "it is beautiful, and surprising."
Scientists published six separate papers about Vesta on Friday in the journal Science, with Russell serving as co-author on all of them. Following the conclusion of its mission to monitor Vesta, Dawn will then make the estimated three-year journey to Ceres, the largest identified asteroid, which researchers contend could hold large water sources or ice beneath its outer crust.
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