It's been a record-shattering ride for the Voyager 1 spacecraft since it was launched in 1977. It returned the first spacecraft photographs of Earth and moon. It visited both Jupiter and Saturn. Five years ago, it became the most distant human-made object in space. Now, after traveling 13.5 billion kilometers (8.4 billion miles), it may have already exited the solar system altogether. A team of scientists says that Voyager 1 last year encountered a drop in the solar wind speed, suggesting it had reached the transitional region between our solar system and interstellar space. However, another group of scientists maintains that Voyager 1 is near the "termination shock," the boundary of our solar system where the solar winds change from supersonic to subsonic flow, but has not yet crossed into it. Either way, Voyager 1 is charting unexplored territory.

"It's the first time a human-made object has been flirting with the boundary between our solar system and interstellar space," said Stamatios Krimigis, head of the space department at Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, who is leading the team of scientists arguing that Voyager 1 already exited our solar system. "We're getting out of the cocoon of solar influence."

View: Full Article | Source: National Geographic