, Vesta dwarfs all of these small bodies. Many scientists think it's a protoplanet left over from the solar system's first few million years.)
Comparative imagery of nine asteroids. With a diameter of about 330 miles (530 kilometers), Vesta dwarfs all of these small bodies. Many scientists think it's a protoplanet left over from the solar system's first few million years.
Image: NASA/JPL-Caltech/JAXA/ESA
New observations from a NASA spacecraft show that the huge asteroid Vesta is a battered protoplanet left over from the solar system's early days, with a unique mix of characteristics unknown from any other space rock.
Scientists had thought that Vesta, the second-largest body in the main asteroid belt between Mars and Jupiter, probably started down a planet-forming path shortly after the solar system's birth. Data gathered by NASA's Dawn probe have now confirmed that suspicion, researchers announced in a raft of studies that came out today (May 10) in the journal Science.
"We now know that Vesta is the only intact, layered planetary building block surviving from the very earliest days of the solar system," Dawn deputy principal investigator Carol Raymond, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., told reporters today.
The other objects like Vesta, researchers added, were probably incorporated into full-fledged planets or destroyed by collisions long ago. [Photos: Asteroid Vesta by Dawn Probe]
Some surprises
"Those studying meteorites that have fallen to Earth, many from Vesta, had produced a theory on the evolution of the solar system and what Vesta should be made of," said Dawn principal investigator Chris Russell of UCLA, lead author of one of the six new Science papers.
"They were very, very right," Russell told SPACE.com via email. "This is good, because we can now use that model to understand more about the solar system."
But Dawn has also delivered some surprising new results. The gigantic Rheasilvia basin at Vesta's south pole, for example, apparently was created by a massive impact just 1 billion years ago or so — long after the solar system's collision-filled "shooting gallery" stage is thought to have ended.
"An age of about 1 billion years for Rheasilvia is unexpectedly young," Simone Marchi of the Southwest Research Institute in Boulder, Colo., lead author of another of the new papers, said in a statement. "This result has important implications for our understanding of the evolution of Vesta, its asteroid family and the inner main asteroid belt in general."
"We have just started exploring Vesta’s secrets, and I’m sure other intriguing results will come along shortly," Marchi added.
The protoplanet Vesta
With a diameter of about 330 miles (530 kilometers), Vesta is roughly as wide as the U.S. state of Arizona. In the main asteroid belt, only the dwarf planet Ceres is bigger.
The $466 million Dawn spacecraft arrived at the huge asteroid in July 2011 to help unlock its many secrets. One of the probe's main missions, researchers said, is to determine if Vesta is indeed a long-surviving protoplanet — a body left over from the solar system's first few million years, many of which later coalesced to form rocky planets such as Earth and Mars.
Scientists got this idea mainly by examining fallen howardite-eucrite-diogenite (or HED) meteorites, which are thought to come from Vesta. The new Dawn results strongly support the protoplanet notion — by confirming that Vesta is indeed the HED meteorites' parent body, for starters.
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8 Comments
Add CommentIt would be interesting to see an article about proto-panets like Vesta and the moons of Saturn and Jupiter which are also identified as proto-planets - Like Dione. Where were they formed in the solar system, what are the relative sizes of their cores, their surface composition. Some of this must be possible now that both Jovian and Saturian systems have been surveyed extensively, especially Saturn with numerous moon flybys to date.
Reply | Report Abuse | Link to thisI agree with Algie ; these are some of the most fascinating objects in the Solar System ! But in that case, please make it a longer, more detailed article....
Reply | Report Abuse | Link to thisHenri
"please make it a longer, more detailed article...."
Reply | Report Abuse | Link to thisTry reading page 2 or 3, accessed by the links with the appropriate number below the text, or by clicking the 'Next' link in the same area of the page.
Now that that is settled, perhaps we can start strip mining the thing now? Drill, baby, drill.
Reply | Report Abuse | Link to thisWith the huge distance between mars and jupiter, and the aseroid belt contained there it seems possible that two planets may have collided and produced this belt. With some asteroids being "rocky" and others varying as partially or completly metalic suggests these formed in a process of planatary specific gravity/density like the Earth or Mars.
Reply | Report Abuse | Link to thisI have no data to support this theory, but maybe there is.
Dear «village geek», whatever made you think that I hadn't read all three pages of the above article regarding Vespa ? Whatever it was, you were sadly deluded. However, not being a member of the Tweeter generation, I do hope that any coming article on proto-planets will be alloted more than these three brief pages ; the subject certainly deserves that much....
Reply | Report Abuse | Link to thisHenri
Very cool discoveries...and more to come...
Reply | Report Abuse | Link to thisI hope for an asteroid with commercial value, for example, solid gold, that would spur the private sector into developing the means to capture it and drag it into earth orbit for exploitation. A real viable space race would be the result. Government doesn't have the incentive to get us to where many of us wish to be.
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