LOS ANGELES - Voyager 1 has crossed a new frontier, becoming the first spacecraft ever to leave the solar system, NASA said Thursday.
Thirty-six years after it was launched from Earth on a tour of the outer planets, the plutonium-powered probe is more than 111/2 billion miles from the sun, cruising through interstellar space - the vast, cold emptiness between the stars, the space agency said.
Voyager 1 actually made its exit more than a year ago, according to NASA. But it's not as if there's a dotted boundary line or a signpost out there, and it was not until recently that scientists with the space agency had enough evidence to say that the probe had finally plowed through the hot plasma bubble surrounding the planets and escaped the sun's influence.
While some scientists remain unconvinced, NASA celebrated with a news conference featuring the theme from "Star Trek."
"We got there," said mission chief scientist Ed Stone of the California Institute of Technology, adding that the spacecraft was "setting sail in the cosmic seas between the stars."
While Voyager 1 may have left the solar system as most people understand it, it still has hundreds, perhaps thousands, of years to go before bidding adieu to the last icy bodies that make up our neighborhood.
Voyager 1 will now study exotic particles and other phenomena in a never-before-explored part of the universe littered with ancient star explosions and radio the data back to Earth, where the Voyager team awaits the starship's discoveries.
The interstellar ambassador also carries a gold-plated disc containing multicultural greetings, songs and photos, just in case it bumps into an intelligent species.
Voyager 1's odyssey began in 1977 when the spacecraft and its twin, Voyager 2, were launched on a tour of the gas giant planets of the solar system. After beaming back dazzling postcard views of Jupiter's giant red spot and Saturn's shimmering rings, Voyager 2 hopscotched to Uranus and Neptune. Meanwhile, Voyager 1 used Saturn as a gravitational slingshot to power itself past Pluto.