Nearly five decades after its launch from Cape Canaveral, Voyager 1 will cross a threshold defined not by matter but by light itself — on November 18, 2026, at 2:16 a.m. Pacific time, it will sit so far from Earth that even a signal traveling at the speed of light will require a full day to arrive, and another to return. No physical boundary marks this place; the milestone belongs entirely to the geometry of communication and the patience of those who built something meant to last a few years and watched it travel for half a century. It is, in the quietest sense, humanity's first correspondenc