Asteroid rockhounds rejoice: NASA unveils geologic map of Vesta

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Asteroid rockhounds rejoice: NASA unveils geologic map of Vesta
Vesta, an asteroid the size of Arizona, gets its own geologic map showing its history of meteorite impact craters over its billions of years of existence.
CNET
by  Amanda Kooser @akooser /November 18, 2014 10:40 AM PST



Vesta sports some interesting geologic history.  NASA/JPL-Caltech/ASU




Humankind recently managed to land a spacecraft on a comet, so it's not too far-fetched to imagine we may some day set an expedition down on Vesta, a large asteroid that came under study by NASA's Dawn Mission. NASA describes Vesta and other asteroids like it as "remnants of the formation of the solar system." The Dawn spacecraft collected a considerable amount of data about Vesta, which scientists have used to create a fascinating geologic map of the asteroid that shows its long history of meteorite impacts.

"The geologic mapping campaign at Vesta took about two-and-a-half years to complete, and the resulting maps enabled us to recognize a geologic timescale of Vesta for comparison to other planets," says Arizona State University's David A. Williams, one of a team of scientists who translated Dawn's data into the geologic map.

Special cameras onboard Dawn have helped scientists determine the asteroid's geologic timescale. On the map, brown colors represent the oldest surfaces, which are pockmarked with heavy crater activity. The purple colors indicate spots shaped by what's known as the Veneneia impact, created by a large meteorite. Green and yellow areas show relatively recent activity on the asteroid's surface.

It's difficult for scientists to accurately determine the age of the various meteorite impacts, but estimates place the Veneneia impact, for example, as having happened likely between 2.1 billion and 3.5 billion years ago.

Vesta has an unusual connection to Earth that Dawn helped to verify. The asteroid was believed to be the source of basaltic meteorites found on our planet. Dawn's observations mesh with this idea, meaning that scientists on our blue marble have actual samples of an asteroid that has been under study by a NASA spacecraft.

Vesta is roughly the the size of Arizona and can sometimes be seen by the naked eye from Earth, though binoculars and telescopes are a big help. Dawn has already moved on from Vesta and is currently heading toward dwarf planet Ceres, the largest object in the asteroid belt where Vesta resides. Its planned arrival there in March 2015 will launch a new chapter in Dawn's exploration of this fascinating corner of the galaxy.


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