Voyager 1 has flown since 1977 and still hasn't covered one light-day

Voyager 1, launched in 1977, is the most distant human-made object in space. Despite nearly 50 years of continuous flight, it has still not travelled the equivalent of one light-day — the distance light covers in 24 hours. The comparison starkly illustrates the vast scale of the universe and the limitations of current propulsion technology.