NASA's Voyager 1 spacecraft has discovered a new layer of the solar system that scientists hadn't known was there, researchers announced today (Dec. 3).
Voyager 1 and its sister probe Voyager 2 have been traveling through space since 1977, and are close to becoming the first manmade objects to leave the solar system.
Scientists haven't been sure exactly when that exit would occur, and now say the spacecraft are likely in the outermost region of the solar system, which is defined by the extent of the heliosphere, the large bubble of charged particles the sun puffs out around itself. Voyager 1, in particular, has entered a new region of the heliosphere that scientists are calling a "magnetic highway," which allows charged particles from inside the heliosphere to flow outward, and particles from the galaxy outside to come in.
"We do believe this may be the very last layer between us and interstellar space," Edward Stone, Voyager project scientist based at the California Institute of Technology, in Pasadena, Calif., said during a teleconference with reporters. "This region was not anticipated, was not predicted."
Therefore, he said, it's hard to predict how soon Voyager will leave the solar system behind altogether.
"We don’t know exactly how long it will take," Stone said. "It may take two months, it may take two years."
The scientists don't think the Voyagers have left the solar system yet because of the orientation of the magnetic field they detect. So far, this field still runs east-west, in agreement with the field created by the sun and twisted by its rotation. Outside the solar system, models predict the magnetic field to be orientated more north-south.more