The Voyager 1 spacecraft has left our solar system, marking a new milestone for the satellite, which was launched 36 years ago.
NASA confirmed Thursday that the spacecraft had crossed the frontier, becoming the first man-made object to ever punch through the solar system and enter interstellar space. It is now about 19 billion kilometres from our sun.
After analyzing Voyager 1's data that is continuously sent back to Earth, NASA determined that the spacecraft likely left the heliosphere on Aug. 25, 2012.
Voyager project scientist Ed Stone said the research team behind the spacecraft now has key data to confirm the boundary crossing. A report on the analysis of the new data was published Thursday in the journal Science.
"The Voyager team needed time to analyze those observations and make sense of them. But we can now answer the question we've all been asking -- 'Are we there yet?' Yes, we are," he said Thursday in a statement on NASA's website.
The spacecraft is now in completely unchartered territory, Prof. Paul Delaney, a physics and astronomy professor at York University, told CTV News Channel.
"That region is unexplored, virgin territory," Delaney said. "We now have a spacecraft that's actually there sampling it… it really is very historic."
Originally launched in 1977 -- the same year the original Star Wars came out -- Voyager 1 was supposed to tour the outer planets and send back photos and data for four years. Its twin, Voyager 2, was also launched that year.
By 1990 it had stopped sending pictures in an effort to save energy, but it continues to transmit data collected through its sensors via a 23-watt transmitter, Delaney said.
"Think about that, your light bulb in your refrigerator gives off more energy than the transmitter on the Voyager."
The spacecraft still has four functioning instruments that continue to collect information about the surrounding environment, which will likely last at least another 10 years, he added.
"The Voyager 1 is the little spacecraft that continues to perform above all expectations."
And while the satellite is expected to be functionally dead by 2025, it could potentially continue its travels forever, according to Daily Planet's Dan Riskin.
"This thing will be going for a million years," he said.
In the chance they ran into aliens, both Voyagers were equipped with gold audio-visual discs carrying information about life on Earth.
The discs included greetings from prominent humans such as U.S. President Jimmy Carter and the UN Secretary General, a selection of songs from Mozart, Chuck Berry and blues artist 'Blind' Willie Johnson, and photos of Earth.
There was even a diagram showing the solar system and explaining that the Voyagers came from the third planet from the sun, Riskin said. "So who knows, maybe in a few million years somebody's going to come knocking."
While the spacecraft actually left the solar system more than a year ago, it was only recently that NASA scientists were able to confirm that it had actually broken through.
A sudden spike in charged particles from the sun followed by a sudden drop indicated to scientists that Voyager 1 had crossed over, Riskin said.
However, Voyager scientists didn't observe any change in the direction of the magnetic field lines, which usually indicates a border has been crossed.
It wasn't until a solar explosion caused a massive echo in the space around the satellite that scientists had data to confirm their suspicions.
"It took us 10 seconds to realize we were in interstellar space," Voyager scientist Don Gurnett said.
But some scientists would like to wait and see more evidence first.
"It's premature to judge," University of Michigan space science professor Lennard Fish said. "Can we wait a little while longer? Maybe this picture will clear up the farther we go."
Now Voyager 1 will examine a part of the universe that's never been explored and keep transmitting data back to Earth.
Scientists estimate it may take three years for Voyager 2 to also leave the solar system.
With files from The Associated Press
