Human-Made Objects Have Reached Interstellar Space

Originally launched in 1977, the Voyager 1 spacecraft's primary mission was to explore Jupiter and Saturn. Taking advantage of a rare planetary alignment, it provided humanity's first close-up views of these gas giants and their moons, discovering active volcanoes on Io and intricate details of Saturn's rings. After completing its tour of the outer planets, Voyager 1 embarked on an extended mission, journeying toward the uncharted territory at the edge of our solar system. This new goal was to reach the boundary where the Sun's influence wanes and the vast expanse of interstellar (Review) space begins.

The Sun creates a massive bubble of charged particles and magnetic fields around the solar system called the heliosphere. Its outer edge, known as the heliopause, is the point where the solar wind is no longer strong enough to push back the stellar winds from surrounding stars. After a 35-year journey, scientists confirmed that on August 25, 2012, Voyager 1 had crossed this final frontier. This marked the first time a human-made object had entered interstellar space, the region between the stars.

Now the most distant human-made object, Voyager 1 continues its journey, currently more than 15 billion miles from Earth. Despite its 1970s technology and a weakening power source, the resilient probe still sends back data from its instruments, offering unique insights into the interstellar medium. These signals, traveling at the speed of light, now take nearly a full day to reach us, a testament to the immense cosmic distances it has traveled.