Ed Stone (Caltech)

The Voyager Journey to the Edge of Interstellar Space

Following their encounters with Jupiter, Saturn, Uranus, and Neptune, the two Voyager spacecraft are exploring the outer reaches of the heliosphere where the solar wind strongly interacts with the wind in the local interstellar medium. On August 25, 2012, Voyager 1 entered a region at the outer boundary of the heliosphere in which the spiral solar magnetic field lines appear to be well connected to interstellar space, allowing efficient interchange of energetic ions from inside the heliosphere with galactic cosmic rays from outside. These unexpected observations have suggested new models of the interaction of the solar and interstellar winds.