Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NASA's Dawn Sees Young Face on Giant Asteroid

05.11.2012
Like a Hollywood starlet constantly retouching her make-up, the giant asteroid Vesta is constantly stirring its outermost layer and presenting a young face.

Data from NASA's Dawn mission show that a common form of weathering, which occurs on many airless bodies in the inner solar system like the Moon, does not age Vesta’s outermost layer.


NASA/JPL-Caltech/UCLA/MPS/DLR/PSI/Brown

This image from NASA's Dawn spacecraft shows a close up of part of the rim around the crater Canuleia on the giant asteroid Vesta. Canuleia, about 6 miles (10 kilometers) in diameter, is the large crater at the bottom-left of this image. This close-up image illustrates the structure of the interior of the crater and complex details of the fresh rays across the soil of Vesta. The image was taken by Dawn's framing camera on Dec. 29, 2011, from an altitude of about 130 miles (210 kilometers).

Carbon-rich asteroids have also been splattering dark material on Vesta's surface over a long span of its history. The results are described in two papers reported on Nov. 1 in the journal Nature.

David Williams, an associate research professor in ASU’s School of Earth and Space Exploration, is a co-author of the Nature article on Vesta’s dark material, titled “Dark Material on Vesta: Delivering Carbonaceous Volatile-Rich Materials to Planetary Surfaces.”

“The dark material on Vesta has been a perplexing problem, one we first noticed as Dawn approached Vesta in the summer of 2011,” said Williams, a member of the science team task force investigating the dark material. “Through Dawn’s mission at Vesta, it became clear that the dark material was mostly derived from carbon-rich asteroids that impacted Vesta’s surface.”

Early pictures of Vesta showed a variety of dramatic light and dark splotches on its surface. These light and dark materials were unexpected and show Vesta has a brightness range that is among the largest observed on rocky bodies in our solar system.

“Most of the smaller dark material patches are associated with impact craters, forming dark rays of ejecta spreading outward,” Williams said. “There are also large regions of dark material, whose composition suggests they are derived from carbon-rich asteroids – perhaps from one or more large impacts early in Vesta’s history.”

Dawn scientists suspected early on that bright material is native to Vesta. One of their first theories for the dark material suggested it might come from the shock of high-speed impacts melting and darkening the underlying rocks or from recent volcanic activity.

An analysis of data from Dawn’s visible and infrared mapping spectrometer and the framing camera revealed that distribution of dark material is widespread and occurs in small spots and in diffuse deposits, without correlation to any particular underlying geology. The likely source of the dark material is now shown to be carbon-rich asteroids, which are also believed to have deposited hydrated minerals on Vesta.

To get the amount of darkening we now see on Vesta, Williams and colleagues said, scientists estimate about 300 dark asteroids with diameters between 0.6 to 6 miles (1 and 10 kilometers) likely hit Vesta during the last 3.5 billion years. This would have been enough to wrap Vesta in a blanket of mixed material 3 to 7 feet (1 to 2 meters) thick.

“This perpetual contamination of Vesta with material from elsewhere in the solar system is a dramatic example of an apparently common process that changes many solar system objects,” said Thomas McCord, lead author of the Nature paper, who worked with Williams on this study. “Earth likely got the ingredients for life – organics and water – this way.”

Launched in 2007, Dawn spent more than a year investigating Vesta. It departed in September 2012 and is currently on its way to the dwarf planet Ceres.

Williams is a participating scientist on NASA’s Dawn mission. JPL manages the Dawn mission for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Ala. The University of California at Los Angeles (UCLA) is responsible for overall Dawn mission science.

Orbital Sciences Corp., Dulles, Va., designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are international partners on the mission team. The California Institute of Technology, Pasadena, manages JPL for NASA.

For more information about Dawn, visit: http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov.

Skip Derra | Newswise Science News
Further information:
http://www.asu.edu
http://www.nasa.gov/dawn
http://dawn.jpl.nasa.gov

More articles from Physics and Astronomy:

nachricht Tiny Drops of Early Universe 'Perfect' Fluid
02.09.2015 | Brookhaven National Laboratory

nachricht Cosmic recycling
02.09.2015 | European Southern Observatory ESO

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: How wind sculpted Earth's largest dust deposit

China's Loess Plateau was formed by wind alternately depositing dust or removing dust over the last 2.6 million years, according to a new report from University of Arizona geoscientists. The study is the first to explain how the steep-fronted plateau formed.

China's Loess Plateau was formed by wind alternately depositing dust or removing dust over the last 2.6 million years, according to a new report from...

Im Focus: An engineered surface unsticks sticky water droplets

The leaves of the lotus flower, and other natural surfaces that repel water and dirt, have been the model for many types of engineered liquid-repelling surfaces. As slippery as these surfaces are, however, tiny water droplets still stick to them. Now, Penn State researchers have developed nano/micro-textured, highly slippery surfaces able to outperform these naturally inspired coatings, particularly when the water is a vapor or tiny droplets.

Enhancing the mobility of liquid droplets on rough surfaces could improve condensation heat transfer for power-plant heat exchangers, create more efficient...

Im Focus: Increasingly severe disturbances weaken world's temperate forests

Longer, more severe, and hotter droughts and a myriad of other threats, including diseases and more extensive and severe wildfires, are threatening to transform some of the world's temperate forests, a new study published in Science has found. Without informed management, some forests could convert to shrublands or grasslands within the coming decades.

"While we have been trying to manage for resilience of 20th century conditions, we realize now that we must prepare for transformations and attempt to ease...

Im Focus: OU astrophysicist and collaborators find supermassive black holes in quasar nearest Earth

A University of Oklahoma astrophysicist and his Chinese collaborator have found two supermassive black holes in Markarian 231, the nearest quasar to Earth, using observations from NASA's Hubble Space Telescope.

The discovery of two supermassive black holes--one larger one and a second, smaller one--are evidence of a binary black hole and suggests that supermassive...

Im Focus: What would a tsunami in the Mediterranean look like?

A team of European researchers have developed a model to simulate the impact of tsunamis generated by earthquakes and applied it to the Eastern Mediterranean. The results show how tsunami waves could hit and inundate coastal areas in southern Italy and Greece. The study is published today (27 August) in Ocean Science, an open access journal of the European Geosciences Union (EGU).

Though not as frequent as in the Pacific and Indian oceans, tsunamis also occur in the Mediterranean, mainly due to earthquakes generated when the African...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Networking conference in Heidelberg for outstanding mathematicians and computer scientists

20.08.2015 | Event News

Scientists meet in Münster for the world’s largest Chitin und Chitosan Conference

20.08.2015 | Event News

Large agribusiness management strategies

19.08.2015 | Event News

 
Latest News

Tiny Drops of Early Universe 'Perfect' Fluid

02.09.2015 | Physics and Astronomy

Learning from Nature: Genomic database standard alleviates search for novel antibiotics

02.09.2015 | Life Sciences

International research project gets high level of funding

02.09.2015 | Awards Funding

VideoLinks
B2B-VideoLinks
More VideoLinks >>>