A closer look at the solar system's most fascinating asteroid - Micro Stereo Speakers

But that doesn't diminish therichness of the discoveries just published in a series of sixpapers in the journal Science . And it only raises expectations for what we may expect from Dawnin the years ahead. (PHOTOS: Views of the Asteroid Vesta) Vesta is the second largest object in the asteroid belt, measuring360 miles (578 km) across. Only its sister asteroid Ceres, at 606mi.

(909 km) tops it. Both are huge by asteroid standards, butundeniably small on the planetary scale; Vesta's modest mass, forexample, gives it a gravity that's just 2% that of Earth. Still, asartifacts of the long-ago stages of cosmic history (or what NASA,elegantly describes as "special fossils of the early solarsystem"), they have always been very tempting targets, and in 2007,NASA launched Dawn — an innovative, ion-propulsion spacecraft — to reconnoiter them both. Since July 16, 2011, the ship has been orbiting Vesta , at altitudes as low as 125 mi. (200 km), scanning the surfacewith a gamma ray and neutron detector, as well with as a visibleand infrared mapping spectrometer and capturing more than 20,000 images in the process.

Perhaps the most striking of the new findings is how much like aplanet Vesta actually is. The asteroid has taken a severe poundingby other, smaller asteroids in its 4.5 billion year history,producing lots of bits of rubble — known as Vestoids —some of which have fallen to Earth in the form of meteorites.Specimens thought to come from Vesta always intrigued geologistsbecause of their unusually low iron content. This suggested notthat Vesta's iron was missing, but that it had been sequestered inits core during an early, molten stage, in much the way Earth andother larger worlds became layered as they formed and cooled.Analyses of Dawn's orbit around Vesta confirm that this is indeedthe case, with the asteroid's gravity and density pointing to acore measuring about 68 mi. (110 km) across, or 19% of its overalldiameter.

(PHOTOS: The Earth from Space) "Vesta looks like a little planet," says geophysicist ChristopherRussell of UCLA, the Dawn mission's principal investigator. Like a planet too, Vesta once had volcanoes — though not forvery long. Its subsurface magma ocean would have made volcanicturbulence inevitable, but the lack of any plains or other smoothsurface features today suggests that the lava stopped flowing andthe volcanic engine shut down barely 100 million years into theasteroid's history. "The biggest surprise for me was the absence of any evidence ofvolcanic features," says volcanologist and Dawn mission scientistDavid Williams. "Vesta's surface has been so heavily modified byimpact cratering that any evidence of its early volcanic activityhas been destroyed." But in many ways that makes Vesta more topographically interesting,with cliffs, hills, ridges, troughs and a massive mountain morethan twice the height of Mt.

Everest rising in its RheasilviaBasin. That basin measures about 500 mi. (310) km across and wasfirst spotted by the Hubble Space Telescope. Rheasilvia sits insidethe even bigger Venenia basin, and spectrometry analyses now revealthat that larger trough was blasted out roughly two billion yearsago and Rheasilvia was formed by a second impact about a billionyears later.

(MORE: A Leisurely Cruise on the Good Ship Solar System) "Seeing two [impacts] was a real discovery and getting their agesis even better," says Russell. Perhaps most surprising to the Dawn scientists was the innateloveliness of Vesta itself. Microscopic cross-sections of Vestanmeteorites had already shown them to have a jewel-like interior,but that's true of most geologic specimens when you look at themclosely enough. Vesta's landscape, however, turned out to have itsown beauty, even if it's one painted in a palette of grays andwhites and blacks.

"We knew Vesta's surface had some variation in color," saysRussell, "but we did not expect the diversity that we see or theclarity of the colors and textures, or their distinct boundaries." It's a measure of what a success the Dawn mission has been so farthat the principal investigators can allow themselves to thrill inthe simple aesthetics of Vesta. They will get two more months oflingering looks before Dawn fires up its ion engine and shoves offfor Ceres, which it will reach in February of 2015 and study forfive months. Asteroids may never seem as newsworthy as full-blownplanets, but you can't understand the modern solar system withoutunderstanding the ancient one. Vesta and Ceres may be two of therichest textbooks of all.

PHOTOS: The best photos from space in 2011 MORE: How a Pocket-Size Satellite Could Find Another Earth.

The e-commerce company in China offers quality products such as Micro Stereo Speakers , China Rechargeable USB Card Speaker, and more. For more , please visit Rechargeable USB Card Speaker today!

Related Articles - Micro Stereo Speakers, China Rechargeable USB Card Speaker,

Email this Article to a Friend! Receive Articles like this one direct to your email box! Subscribe for free today!