Thirty-six year ago today, on September 5th, 1977, Voyager 1 launched into space, and now, after traveling over 18.7 billion kilometres, it is so close to being in interstellar space that scientists can't yet agree on whether it has left the solar system or not.
The changes that prompted some to argue that Voyager 1 had become humanity's first interstellar spacecraft started in June of 2012, when information NASA was receiving from the probe indicated that it was seeing more particles from interstellar space and fewer particles from our sun. The only thing that was lacking, to make it conclusive, was that the spacecraft should also see a change in the direction of the magnetic field (since the galactic magnetic field points in a different direction than the sun's magnetic field). Since it didn't see that change, NASA is steadfast that the spacecraft still hasn't yet entered interstellar space.
It is the first spacecraft we've had that far out from the sun, though, so it's sending back incredible findings on parts of the solar system that we didn't even know existed!
If you'd like to check out a great computer simulator that shows Voyager's journey through the solar system (as well as for other spacecraft), go to NASA's Eyes on the Solar System. There, you can launch their online simulator or download the simulator to your computer to run whenever you want.
[ More Geekquinox: Prehistoric megashark’s tooth fossils discovered in the Canary Islands ]
Regardless of whether Voyager 1 has actually left the solar system or not, the spacecraft is a spectacular achievement. It already provided us with amazing discoveries on its way past all the planets, and it continues to provide incredible new insights into our solar system as it approaches interstellar space. With its battery expected to last until the year 2020, we should have another seven years of discoveries before it simply becomes an interstellar wanderer, carrying humanity's message to the stars.
(Image courtesy: NASA/JPL-Caltech/JHUAPL)
Geek out with the latest in science and weather.
Follow @ygeekquinox on Twitter!