Where’s the Edge of the Solar System? It’s Complicated…
by Ray Villard
If you thought finding a definition for Pluto was contentious, try defining the edge of the solar system.
A press release from the American Geophysical Union (AGU) last week announced that on August 25, 2012, NASA’s Voyager 1, officially entered interstellar space. This milestone comes after speeding across the solar system for 35 years following its landmark flybys of the Jovian and Saturnian system. The AGU release title read: “Voyager 1 Has Left The Solar System, Sudden Changes In Cosmic Rays Indicate.”
The threshold is described by the authors of the paper, published in Geophysical Journal Letters, as Voyager’s measurement of a substantial increase in the level of galactic cosmic rays slamming into the 1,700 pound spacecraft. This is seen as evidence that Voyager may have crossed a cliff called the heliopause, the edge of tenuous immense bubble of plasma and charged particles blown into space by the solar wind.
The paper abstract reports: “ has crossed a well-defined boundary for energetic particles at this time possibly related to the heliopause.”