PEAKING INTEREST: A towering mound near Vesta's south pole rivals the largest mountains in the solar system.
Image: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
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NANTES, France—Asteroids are often considered debris, the scraps and odd lumps that went unused in the forming of the planets. But when it comes to Vesta, one of the largest asteroids in our solar system, Chris Russell hardly considers the rock a mere castoff. "I've started calling it the smallest terrestrial planet," said Russell, the principal investigator for NASA's Dawn mission, which sent a spacecraft into orbit at Vesta in July.
Russell and his colleagues gave a sense Monday of why they hold Vesta in such high regard. In a press conference here at a joint meeting of the American Astronomical Society Division for Planetary Sciences and the European Planetary Science Congress, researchers working on the Dawn mission announced some of the findings that the spacecraft has collected since entering orbit—findings that make Vesta look considerably more like a world unto itself than a mere leftover. "We found that Vesta is a really interesting alien, small world," said the mission's deputy principal investigator, Carol Raymond of the NASA Jet Propulsion Laboratory in Pasadena, Calif.
Vesta is an irregular ellipsoid just 560 kilometers in diameter—too small and odd-shaped to qualify as a dwarf planet. But it seems to have a large metallic core and a basaltic crust, just like Earth. And it bears scars from past geologic shake-ups, most likely triggered by large impacts, including rift valleys, mountainous uplifts and an intriguing belt of grooves near its equator. "It has tectonic features, like on Earth," Russell said.
The asteroid made a particularly interesting target for Dawn because the space rock carries evidence of the history of much of the solar system as well. Vesta-derived meteorites that landed on Earth allowed planetary scientists to measure the asteroid's age in the laboratory, showing that it is one of the oldest large bodies in the solar system. (Because it is small relative to the terrestrial planets, it would have cooled and solidified much more quickly than those bodies.) As such, Vesta provides a valuable lab for studying the materials and processes that formed the planets during the first millions of years in the early solar system.
It now appears that the past four billion years have been quite an interesting time in Vesta's evolution as well. In fact, the asteroid boasts a mountain that Earth cannot match in terms of altitude. A giant peak at the asteroid's south pole, which is currently unnamed, rises roughly 20 kilometers from its base to its summit, about twice the height of Mauna Kea in Hawaii, the tallest mountain—from its base on the ocean floor to its peak—on Earth.
"The south polar mountain on Vesta is very, very large—almost as large as the largest mountain in the solar system, Olympus Mons," Russell said, referring to the towering, roughly 25-kilometer volcanic peak on Mars. "We have not figured out the tectonic cause of the south polar mountain, so that's work ahead of us."
The mountain rises from the center of a large impact basin, but Raymond cautioned that it was too soon to definitively say that the peak is simply a crater with an impact-uplifted center. A large impact in the south billions of years ago did leave one clearly identifiable mark, blanketing the southern hemisphere in ejecta and filling nearby craters. A preliminary chronology analysis based on crater counts across the asteroid shows that something reset the clock on the southern hemisphere long ago. "Ages from some areas in the south appear to be much younger, as much as a billion years younger, than the north," Raymond said.
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11 Comments
Add CommentWhy do people with little curiosity about things read? If you want a nice fat article, you probably want to sub to something. This is free. Take it. Leave it, don't complain about it like they owe you something else.
Reply | Report Abuse | Link to this"No duh, dorkenheimerschmidt." Well, that's a few grades above the "kindergarten-grade" you complain about, but not out of the sandbox yet.
Reply | Report Abuse | Link to thisWhy do you get your jollies trashing stories instead of at least trying to write your own? Rejected, were you?
Your living proof that humans evolved from monkeys. You probably scratch your butt and sniff your fingers to just for kicks.
Reply | Report Abuse | Link to thisUnbeliever - you apparently miss the point. Scientists are not interested in Vesta because it LOOKS like it has mountains or other features. It is interesting because it appears that such features were developed due to tectonic processes that were not particularly expected for such a small body.
Reply | Report Abuse | Link to thisCongratulations though, your comments were almost humorous!
Lookie-Lookie - Leave "Unbeliever" alone to evolve at the slower pace that is his Lot and those other Neo-Sapiens who naively & cowardly remained swinging in the Jungle Trees for Eons longer than the rest of Us who's greater curiosity brought us down from the swinging brances to the terra-firma savannas where we soon learned by natural selection to get off the Fours and to walk & run on the Two's.. Though He may still be on the low side of the Bell Curve, hopefully in due time and by natural selection his Progeny may better assend the steeper side of the Curve and actually contribute an Intelegent thought to the Scientific American Base..
Reply | Report Abuse | Link to thisWell, it seems the post from our semi-resident sub-span dwelling troglodyte (troll) has been removed.
Reply | Report Abuse | Link to thisWhy is it that whenever I go to read the comments left by readers of scientific articles, they often seem to degrade into silly power-play arguements that have nothing whatsoever to do with the article upon which they are supposedly commenting? What a shame to waste such a forum...how about sharing inspiration and ideas instead? Like...wouldn't it be cool to build some kind of a space station ON Vesta??? Imagine what we could learn, not only about Vesta herself but about living in the hostile environment of space....we could build very large telescopes, and radio telescopes and get a whole different view than we get from earth and from space. Just a thought for discussion, rather than picking on each other. I wonder how CMEs would affect such a place? I wonder if you could build something like the tevetron out there and do even more with it?
Reply | Report Abuse | Link to thisIt's possible another object relative smaller size of Vesta, hit the Vesta and jointed together, and left a mountain on its surface.
Reply | Report Abuse | Link to thisThe NASA photos which I have re-rendered show human society on them: people in relationship. You will see what you want and expect to see. :)
Reply | Report Abuse | Link to thisIf we do build a Vesta station, I have some suggestions for crew members. Are they taking nominations?
Reply | Report Abuse | Link to this.
Reply | Report Abuse | Link to thisLooks like a rather primitive society to me. I wouldn't bother, if I were you.