Voyager 1 has left the solar system: NASA says new research proves it’s found interstellar space

NASA thinks it’s finally settled when Voyager 1 left our solar system: on or around August 25th, 2012. The first Voyager probe launched in 1977, but while it’s indubitably passed into previously unexplored parts of space, it’s been hard to say whether it’s actually crossed over into interstellar space. Now, a paper published in Science lays out a convincing case that it did so over a year ago. University of Iowa physics professor Donald Gurnett and his co-authors, as well as NASA itself, believe that the density of plasma around Voyager 1 shows it’s no longer within the boundaries of the heliosphere, the bubble of solar energy that surrounds our system. And by working backwards, it’s possible to pinpoint (relatively speaking) the moment it left.