Voyager I leaves the solar system, NASA says

The Voyager I spacecraft</p>

The Voyager I spacecraft

After months of speculation, it's official. 

Voyager I has left the solar system.

The news makes NASA's space probe the first human-made object to enter interstellar space, according to evidence published Thursday in the journal Science.

More from GlobalPost: NASA's Voyager probe reaches boundary of our solar system

"Voyager has boldly gone where no probe has gone before, marking one of the most significant technological achievements in the annals of the history of science," John Grunsfeld, NASA's associate administrator for the Science Mission Directorate, told the Los Angeles Times.

"New and unexpected" data indicates Voyager 1 has been traveling in interstellar space for about a year now, NASA said.

The study published earlier this year suggested the space probe reached that milestone on Aug. 25, 2012, based off drastic changes in radiation levels not seen since Voyager 1 launched decades ago.

However, NASA dismissed the findings at the time, and in June announced the probe had reached the boundary of our solar system about 11 billion miles from Earth.

More from GlobalPost: Voyager I close to leaving solar system, report says

It's now estimated to be about 12 billion miles from our planet.

Voyager 1 and 2 were launched in 1977 and have been flying through space ever since.

Though initially tasked with exploring Jupiter and Saturn, they were then sent even further.

They are said to have discovered Jupiter's volcanoes and more details about Saturn's rings.

Voyager 2 is the only probe to have ever reached Uranus and Neptune, and Voyager I the only one to reach interstellar space.