After over 40 years, NASA’s Voyager 2 spacecraft has officially entered interstellar space and is now roaming in between the star systems in our galaxy in the outer limits of the solar system.

A region known as the heliosphere is what surrounds the planets in our solar system, which is a giant bubble formed by solar wind and hits the matter and radiation floating between solar systems in a galaxy.

NASA announced that its Voyager 2 became the second human-made object, after Voyager 1, to exit the heliosphere and enter into interstellar space between the stars. The spacecraft is now over 18 billion kilometers from Earth – a distance that is equivalent to more than 164 round-trip journeys between Mars and Earth, explained Futurism.

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The Voyager 2 contains the Plasma Science Experiment (PLS) instrument that is designed to give valuable data about the boundary between the heliosphere and interstellar space. The Voyager 1, which entered interstellar space in 2012, too had a PLS, but it failed long before the craft exited the heliosphere.

“Even though Voyager 1 crossed the heliopause in 2012, it did so at a different place and a different time, and without the PLS data. So we’re still seeing things that no one has seen before,” said principal investigator for the PLS instrument, John Richardson.

As per Mashable, the Voyager 2 is, however, still in the distant realms of the solar system and isn’t expected to leave the solar system anytime soon. NASA suspects that it will take another some 30,000 years for the Voyagers to travel beyond the Oort Cloud – collection of objects including comets orbiting Sun and really far beyond Pluto – and travel to the ‘uncharted territory’.

Moreover, both the Voyagers were originally intended to explore the solar system for five years, but are still alive and sending messages back to Earth even after 41 years after being launched in 1977.