For as long as humans have looked upward, the question of how the universe ends has hovered at the edge of the knowable. Now, cosmologists working from measurements of dark energy and cosmic expansion rates have produced a conditional timeline for the universe's ultimate unraveling — a scenario in which accelerating expansion tears galaxies, stars, and matter itself apart in an event known as the Big Rip. The calculation does not claim prophecy, but it marks a meaningful moment: the end of everything has become, at least provisionally, a subject of science rather than only of philosophy.