Launched in 1977, Voyager 1 has been cruising through space for nearly 47 years, traveling a mind-boggling distance of almost 16 billion miles from Earth. This journey has already broken records—it was the first spacecraft to cross the heliopause, the boundary where the Sun’s solar wind yields to interstellar space. Now, it is on course to reach a distance known as a light-day, meaning the distance that light travels in 24 hours.

Traveling at about 38,000 miles per hour, Voyager 1’s progress may seem slow compared to light speed, but it reveals the vast scales of cosmic distance. Radio signals sent from the spacecraft take nearly 23 hours to reach Earth, which offers a glimpse into the immense challenges of communicating across these astronomical expanses.