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NASA's Dawn mission says asteroid Vesta formed much the same way Earth did.
Vesta, the asteroid so large some consider it a “proto-planet,” is providing scientists with clues to how our own Earth formed, new research released today suggests.
The journal Nature published two scientific papers about the most recent discoveries in its November 1 issue.
NASA suggests Vesta’s surface is constantly stirring its outermost layer.
Data from NASA’s Dawn mission show that a form of weathering that occurs on the moon and other airless bodies in the inner solar system does not alter Vesta’s outermost layer in the same way.
Carbon-rich asteroids have also splattered dark material on Vesta.
“Dawn’s data allow us to decipher how Vesta records fundamental processes that have also affected Earth and other solar system bodies,” said Carol Raymond, an investigator with NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
NASA launched the Dawn space mission five years ago to observe Vesta and other objects in a meteor belt between Mars and Jupiter.
Dawn left Vesta last month to observe the dwarf planet Ceres, but not before returning the new information.
Over time, soils on our moon and asteroids have undergone extensive weathering, obvious in an accumulation of metallic particles containing iron that dull “fluffy” outer layers, NASA said on its website.
Scientists can’t see the same evidence on Vesta, which remains bright and pristine.
“Getting up close and familiar with Vesta has reset our thinking about the character of the uppermost soils of airless bodies,” said Carle Pieters, a Dawn team member based at Brown University in Providence, R.I. “Vesta ‘dirt’ is very clean, well-mixed and highly mobile.”
Early pictures of Vesta showed a variety of dramatic light and dark splotches its surface.
These light and dark materials were unexpected and now show the brightness range of Vesta are among the largest observed on rocky bodies in our solar system.
To get its darkness, the Dawn team estimates about 300 dark asteroids between 0.6 to 6 miles across likely hit Vesta during the last 3.5 billion years.
“This perpetual contamination of Vesta with material native to elsewhere in the solar system is a dramatic example of an apparently common process that changes many solar system objects,” said Tom McCord, Dawn team member in Winthrop, Wash.
“Earth likely got the ingredients for life – organics and water – this way.”
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