LOS ANGELES (AP) — 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 spacecraft is more than 11 1/2 billion miles from the sun, cruising through what scientists call 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 out there or a signpost, and it was not until recently that NASA had the evidence to convince it of what an outside research team had claimed last month: that the spacecraft had finally plowed through the hot plasma bubble surrounding the planets and escaped the sun's influence.
While some scientists said they remain unconvinced, NASA celebrated.
"It's a milestone and the beginning of a new journey," said mission chief scientist Ed Stone at NASA's Jet Propulsion Laboratory in Pasadena.
Voyager 1 will now study exotic particles and other phenomena in a never-before-explored part of the universe 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.
Voyager 1, which is about the size of a subcompact car, carries instruments that study magnetic fields, cosmic rays and solar wind.