NASA's Voyager 1 spacecraft, first launched in 1977, is on the verge of traveling outside the solar system.
This marks the first time that any spacecraft has ever left the solar system.
The nuclear powered craft is at the mercy of solar winds, which currently have it navigating through an uncharted void near the edge of the Milky Way. That area, known as the heliopause, is the boundary between the sun's solar winds region of influence (heliosphere) and interstellar space.
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In the latest data, the direction of the magnetic field lines has not changed, indicating Voyager is still within the heliosphere, the bubble of charged particles the sun blows around itself. The data do not reveal exactly when Voyager 1 will make it past the edge of the solar atmosphere into interstellar space, but suggest it will be in a few months to a few years.
NASA says Voyager 1 currently about 11 billion miles from the sun. According to a new article in Astronomy Now, the craft has enough power to continue its scientific investigations through 2020, and should remain functional for another five years after that. Experts urge taking the long view in sizing up Voyager's post-solar breakthrough, however:
"What we're talking about today with all these new developements is simply one more chapter in a scientific inquiry that began over 100 years ago," said Eugene Parker, professor emeritus of physics at the University of Chicago.
However, NASA officials say they won't know the exact moment that Voyager passes outside the solar system. "That transition may not be instantaneous," said Voyager project scientist Ed Stone. "It may take us months to get through a rather messy interface between these two winds."
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