After almost a year of debate, NASA has accepted the idea that its Voyager 1 probe has left behind the last wisps of the solar wind and is flying through interstellar space. But has it left the solar system? Um, not exactly.
It depends on what you mean by "solar system": The findings reported Thursday in the journal Science have convinced even the skeptics that the car-sized spacecraft has gone beyond the heliosphere, the huge bubble of electrically charged particles emanating from the sun. But the edge of the heliosphere is not the same as the edge of the solar system.