NASA Mission Suggests Sun And Planets Constructed Differently

Dwayne Brown

Headquarters, Washington                                   

 

DC Agle

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- Analysis of samples returned by NASA’s Genesis mission indicates our sun and its inner planets may have formed differently than scientists previously thought.

The data revealed slight differences in the types of oxygen and nitrogen present on the sun and planets. The elements are among the most abundant in our solar system. Although the differences are slight, the implications could help determine how our solar system evolved.

The air on Earth contains three different kinds of oxygen atoms, which are differentiated by the number of neutrons they contain. Nearly 100 percent of oxygen atoms in the solar system are composed of O-16, but there also are tiny amounts of more exotic oxygen isotopes called O-17 and O-18. Researchers studying the oxygen of Genesis samples found that the percentage of O-16 in the sun is slightly higher than on Earth, the moon, and meteorites. The other isotopes’ percentages were slightly lower.

"The implication is that we did not form out of the same solar nebula materials that created the sun -- just how and why remains to be discovered," said Kevin McKeegan, a Genesis co-investigator from the University of California, Los Angeles and the lead author of one of two Science papers published this week.

The second paper detailed differences in the amount of nitrogen on the sun and planets. Like oxygen, nitrogen has one isotope, N-14, that makes up nearly 100 percent of the atoms in the solar system, but there also is a tiny amount of N-15. Researchers studying the same samples saw that when compared to Earth's atmosphere, nitrogen in the sun and Jupiter has slightly more N-14, but 40 percent less N-15. Both the sun and Jupiter appear to have the same nitrogen composition.

"These findings show that all solar system objects, including the terrestrial planets, meteorites and comets, are anomalous compared to the initial composition of the nebula from which the solar system formed," said Bernard Marty, a Genesis co-investigator from Centre de Recherches Petrographiques et Geochimiques in Nancy, France and the lead author of the second new Science paper. "Understanding the cause of such a heterogeneity will impact our view on the formation of the solar system."

Data were obtained from analysis of Genesis samples collected from the solar wind -- the material ejected from the outer portion of the sun. This material can be thought of as a fossil of our nebula because the preponderance of scientific evidence suggests that the outer layer of our sun has not changed measurably for billions of years.

"The sun houses more than 99 percent of the material currently in our solar system so it's a good idea to get to know it better," said Genesis principal investigator Don Burnett of the California Institute of Technology in Pasadena, Calif. "While it was more challenging than expected we have answered some important questions, and like all successful missions, generated plenty more."

Genesis launched in August 2000. The spacecraft traveled to Earth’s L1 Lagrange Point about 1 million miles from Earth, where it remained for 886 days between 2001 and 2004, passively collecting solar-wind samples.

On Sept. 8, 2004, the spacecraft released a sample return capsule, which made a hard landing as a result of a failed parachute in the Utah Test and Training Range in Dugway, Utah. This marked NASA’s first sample return since the final Apollo lunar mission in 1972, and the first material collected beyond the moon. NASA’s Johnson Space Center in Houston curates the samples and supports analysis and sample allocation.

NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed the Genesis mission for NASA’s Science Mission Directorate in Washington. The Genesis mission was part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems in Denver developed and operated the spacecraft. Analysis at the Centre de Recherches Petrographiques et Geochimiques was supported by the Centre National d’Etudes Spatiales and the French National Center for Scientific Research in Paris.

For more information on the Genesis mission, visit http://genesismission.jpl.nasa.gov.

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NASA Spacecraft Captures Video Of Asteroid Approach

Dwayne Brown

Headquarters, Washington

 

Jia-Rui Cook

Jet Propulsion Laboratory, Pasadena, Calif.

 

WASHINGTON -- Scientists working with NASA's Dawn spacecraft have created a new video showing the giant asteroid Vesta as the spacecraft approaches this unexplored world in the main asteroid belt.

The video loops 20 images obtained for navigation purposes on June 1. The images show a dark feature near Vesta's equator moving from left to right across the field of view as Vesta rotates. Images also show Vesta's jagged, irregular shape, hinting at the enormous crater known to exist at Vesta's south pole.

To see the video, visit http://www.nasa.gov/dawn.

The images were obtained by a framing camera during a 30-minute period and show about 30 degrees of a rotation. The pixel size in these images is approaching the resolution of the best Hubble Space Telescope images of Vesta.

"Like strangers in a strange land, we're looking for familiar landmarks," said Jian-Yang Li, a Dawn participating scientist from the University of Maryland, College Park. "The shadowy spot is one of those – it appears to match a feature, known as 'Feature B,' from images of Vesta taken by NASA's Hubble Space Telescope."

Before orbiting Vesta on July 16, Dawn will gently slow down to about 75 mph (120 kph). NASA is expecting to release more images on a weekly basis, with more frequent images available once the spacecraft begins collecting science at Vesta.

"Vesta is coming more and more into focus," said Andreas Nathues, framing camera lead investigator, based at the Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany. "Dawn's framing camera is working exactly as anticipated."

The mission is managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif., for the agency'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. UCLA is responsible for overall Dawn mission science. Orbital Sciences Corp. of Dulles, Va., designed and built the Dawn spacecraft. The framing cameras were developed and built under the leadership of the Max Planck Institute for Solar System Research in Katlenburg-Lindau, Germay.

The German Aerospace Center (DLR) Institute of Planetary Research in Berlin made significant contributions in coordination with the Institute of Computer and Communication Network Engineering in Braunschweig. The framing camera project is funded by the Max Planck Society, DLR and NASA.

The video from Dawn also will air Monday afternoon on NASA Television's Video File. For NASA TV downlink information, schedules and links to streaming video, visit http://www.nasa.gov/ntv.

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