Edward C. Stone is the David Morrisroe Professor of Physics at the California Institute of Technology (Caltech) and Vice Provost for Special Projects. He is a former Director of the Jet Propulsion Laboratory (1991-2001), has served as chair of Caltech's Division of Physics, Mathematics, and Astronomy (1983-1988), and oversaw the development of the Keck Observatory as Vice President for Astronomical Facilities (1988-1990).

Since 1972, Stone has been the project scientist for the Voyager Mission at the Jet Propulsion Laboratory, coordinating the scientific study of Jupiter, Saturn, Uranus, and Neptune and Voyager’s continuing exploration of the outer heliosphere and search for the edge of interstellar space. Following his first instrument on a Discoverer satellite in 1961, Stone has been a principal investigator on nine NASA spacecraft and a co-investigator on five other NASA missions for which he developed instruments for studying galactic cosmic rays, solar energetic particles, and planetary magnetospheres.

Stone is a member of the National Academy of Sciences and the American Philosophical Society, president of the International Academy of Astronau¬tics, and a vice president of COSPAR. Among his awards and honors, Stone received the National Medal of Science from President Bush (1991), the Magellanic Premium from the American Philosophical Society, and Distinguished Service Medals from NASA. In 1996, asteroid (5841) was named after him.

Exploring the Final Frontier of the Solar System - 2006 Waynick Lecture

After a twenty-seven year journey, Voyager 1 reached the final frontier of the solar system nine billion miles from Earth. The atmosphere of the Sun expands supersonically, creating a giant bubble called the heliosphere that envelops all of the planets. Outside the bubble lies interstellar space filled with matter from other stars. Voyager 1 reached a major milestone in its journey when it began exploring the outermost layer of the heliospheric bubble where the supersonic solar wind abruptly slows as it presses outward against the surrounding interstellar matter. Voyager 2 will soon join in exploring this final frontier as both spacecraft continue their journeys to the edge of interstellar space.

Voyager’s Race to the Edge of Interstellar Space - 2006 Colloquium Lecture

In December 2004 at 94 AU, Voyager 1 crossed the shock marking the abrupt slowing of the supersonic solar wind and began exploring the interaction of the Sun with the surrounding interstellar medium. The turbulence in this interaction region is fundamentally different than that in the solar wind and acts as a barrier to the entry of lower energy galactic cosmic rays deeper into the heliosphere. In contradiction to many predictions that the shock was the source of medium energy anomalous cosmic rays, their intensity did not peak at the shock. Their intensity has, however, increased with increasing distance beyond the shock, indicating their origin remains to be discovered. Recent results from Voyager 2 at southern solar latitudes suggest that the shock may be 5 to 10 AU closer than at Voyager 1 in the north, consistent with an asymmetric distortion resulting from interaction with a local interstellar magnetic field. The Voyagers will provide more insight into this interaction and what lies beyond as they continue their race to interstellar space.