Voyager 1 on edge of Solar System
NASA's Voyager 1 probe is tantalizingly close to the edge of the solar system, but predicting when it will finally pop free into interstellar space is a challenging proposition, mission team members say.
Voyager 1
is plying new and exotic terrain at the limits of the sun's sphere of influence, and scientists simply don't know what to expect from these unexplored regions.
"We've never been there before," said Voyager project manager Suzanne Dodd of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "That's what makes it very hard. It's not unlike the first explorers sailing across the Atlantic Ocean to the New World. They thought they might know what they would see, but they saw things that were quite a bit different."
Knocking on the door
Voyager 1 and its twin, Voyager 2, launched a few weeks apart in 1977 to study the giant planets Saturn, Jupiter, Uranus and Neptune. After completing this unprecedented "grand tour," the two probes kept flying, streaking through unexplored realms on their way to interstellar space. [Voyager: Humanity's Farthest Journey (Video)]
It looks like Voyager 1 will get there first. The probe is now more than 11.3 billion miles from Earth, making it the most farflung manmade object in the universe.
Voyager 1 has also encountered strange new conditions in the outer layers of the heliosphere — the huge bubble of charged particles and magnetic fields surrounding the sun — suggesting that the probe may be about to leave the solar system forever.