Sept. 13, 2013

Voyager I Leaves the Solar System

Scientists who have followed NASA's Voyager I mission since its 1977 liftoff now estimate that the probe left our solar system on Aug. 25, crossing from the heliosphere into the interstellar plasma of approaching deep space. National Academy of Sciences members Donald Gurnett and Norman Ness write about this latest Voyager milestone, which follows 36 years of invaluable data plus photos of Jupiter and Saturn that captured the public's imagination.