The Early Solar System:
Surprises from NASA’s Stardust Mission

Dr. Russell Palma
Department of Physics and Astronomy
Minnesota State University, Mankato

Comets are frozen, largely unaltered reservoirs of dust and gases present in the early solar nebula.  They contain records of the chemical, mineralogical, and isotopic character of primordial solar system matter.  On January 15, 2006, NASA’s Stardust Mission returned to Earth with a cargo of particles collected from the coma of comet Wild 2, the first samples of indisputably cometary matter available for laboratory study.

One surprising discovery is of many igneous, refractory “rocks” formed at very high temperatures, presumably close to the early Sun, then somehow transported to the trans-Neptunian Kuiper Belt and incorporated into Wild 2 at about the time of the solar system’s origin.  A second completely unanticipated feature of Stardust samples was finding enormous concentrations (though very small amounts) of He and Ne, suggesting intense ion irradiation.  These two observations, together with Ne isotopic data similar to that found in primitive meteorites, points to gases implanted in Stardust grains from an ancient, energetic nebular reservoir near the young evolving Sun.