Voyager 2 nearing solar system edge

摘要

Earth's second emissary to interstellar space is phoning home with close-up views of the solar system's ragged border. Voyager 2 is about two-thirds of the way to the boundary where interstellar space begins, called the heliopause, which marks the edge of the sun's influence. Its twin, Voyager 1, crossed this border two years ago this week, according to NASA and most Voyager scientists -although some think the probe's readings were inconclusive. Despite being launched the same year, Voyager 2 hasn't yet detected similar signs in the solar wind that would mark its imminent departure, says Rob Decker at Johns Hopkins University in Maryland.