Human-Made Objects Have Reached Interstellar Space

The journey into the vast emptiness between stars began not with a crewed mission, but with a pair of remarkable robotic explorers. Originally designed for a "Grand Tour" of the outer planets, the Voyager 1 and 2 probes far outlived their initial missions. After completing its flybys of Jupiter and Saturn, Voyager 1 continued coasting outward, eventually approaching the boundary of our Sun's influence. This bubble, known as the heliosphere, is a vast region dominated by the Sun's magnetic field and outflowing solar wind. In 2012, after a 35-year journey, Voyager 1 punched through this frontier, called the heliopause, and began measuring the strange, dense plasma of true interstellar space.

Now more than 24 billion kilometers away, its signals take over 22 hours to reach NASA's Deep Space Network. While its instruments are powered by a slowly decaying plutonium source, the probe continues to be humanity's most distant emissary. Attached to its side is the Golden Record, a gold-plated copper phonograph disc intended as a cosmic message in a bottle. It contains sounds of nature, music from various cultures, and 115 images encoded in analog form, serving as a greeting to any intelligent life that might one day encounter the silent probe as it drifts through the Milky Way.