A team of researchers using NASA’s Cassini spacecraft and a ground-based radio-telescope system has accurately determined the center of mass, or barycenter, of Saturn and its moons to within about 4 km. The measurement is about fifty times more precise than the other existing measurements. This image was obtained on 10 September 2007 by NASA’s Cassini spacecraft, at a distance of approximately 3.3 million km from Saturn. Rhea – Saturn’s...
