Voyager 2 Hits the Edge of the Solar System—and Writes Home

Nobody expected to take it this far. When NASA launched two probes named Voyager 1 and Voyager 2 in the summer of 1977, scientists hoped the probes would get as far as Saturn during their five-year mission. Instead, the nuclear-powered explorers are still sending data home over 30 years after their launch, and are currently pushing through the boundary of our solar system into interstellar space. A collection of five papers in tomorrow's issue of the journal Nature [subscription required] analyze the data sent back from Voyager 2 as it reached