Voyager 1 has crossed a new frontier, becoming the first spacecraft ever to leave the solar system enter interstellar space.
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.
NASA has clarified that Voyager 1 has entered interstellar space and not left the solar system. These false alarms are fairly common. From NASA’s explainer blog:
“So, would the team say Voyager 1 has left the solar system? Not exactly – and that’s part of the confusion. Since the 1960s, most scientists have defined our solar system as going out to the Oort Cloud, where the comets that swing by our sun on long timescales originate. That area is where the gravity of other stars begins to dominate that of the sun. It will take about 300 years for Voyager 1 to reach the inner edge of the Oort Cloud and possibly about 30,000 years to fly beyond it. Informally, of course, “solar system” typically means the planetary neighbourhood around our sun. Because of this ambiguity, the Voyager team has lately favoured talking about interstellar space, which is specifically the space between each star’s realm of plasma influence.”