Genesis Mission Suggests Science May Need To Be Adjusted

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.

Genesis Spacecraft

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.

Genesis Collection Wafers

"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.

FMI: http://genesismission.jpl.nasa.gov