12 July 2008
The Voyager Spacecraft approaches the Edge of Interstellar Space
Credit: NASA/JPL
Scientists using data from NASA's Voyager 2 spacecraft have found the bubble of solar wind surrounding the Solar System is not round, but has a dented shape.
The beginning of the transition zone between the heliosphere (the solar wind bubble) and the interstellar space is known as the 'termination shock'. Scientists report that Voyager 2 crossed this boundary closer to the Sun than expected, suggesting that the heliosphere in this region is pushed inward, closer to the Sun, by an interstellar magnetic field. These findings help build up a picture of how the Sun interacts with the surrounding interstellar medium.
Launched in 1977, two Voyager spacecraft were originally scheduled to fly by and study Jupiter and Saturn. When Voyager 1 flew by Saturn, its path sent it above and away from the ecliptic, the plane of Earth’s orbit, in which most planets orbit the Sun. Voyager 2's trajectory continued in the ecliptic, allowing the spacecraft to encounter two other giant planets: Uranus (January 1986) and then Neptune (August 1989). The Voyagers are the most distant space probes; Voyager 1 is approximately 16 billion km away, while Voyager 2 is approximately 13 billion km away. The current mission of Voyager 2, and its companion Voyager 1, is to reach the edge of the Solar System.
Further Reading
Voyager, the Interstellar Mission
http://voyager.jpl.nasa.gov/
JPL
www.jpl.nasa.gov/
Aymen Mohamed Ibrahem
Senior Astronomy Specialist