An anonymous reader writes "A new study released today (abstract) indicates that the Voyager 1 spacecraft has become the first man-made object to exit our solar system. Instrumentation data sent back to NASA indicate the historic event likely occurred on August 25, 2012, evidenced by drastic changes in radiation levels as the craft ventured past the heliopause. What remains to be seen, however, is whether Voyager 1 has actually made it to true interstellar space, or whether it has entered a separate, undefined region beyond our solar system. Either way, the achievement is truly monumental. 'It's outside the normal heliosphere, I would say that. We're in a new region,' said Bill Webber, professor emeritus of astronomy at New Mexico State University in Las Cruces. 'And everything we're measuring is different and exciting.'"
Update: 03/20 20:44 GMT
: Reader skade88 points out that the JPL Voyager team is not so sure
: "It is the consensus of the Voyager science team that Voyager 1 has not yet left the solar system or reached interstellar space. In December 2012, the Voyager science team reported that Voyager 1 is within a new region called 'the magnetic highway' where energetic particles changed dramatically. A change in the direction of the magnetic field is the last critical indicator of reaching interstellar space and that change of direction has not yet been observed." So we'll probably be hearing about this again in a couple years.