For a quarter century, the accelerating expansion of the universe has stood as one of science's most celebrated certainties, earning a Nobel Prize and anchoring the standard model of cosmology. Now, a team of researchers reexamining over 1,700 exploding stars suggests that acceleration may be an artifact of uncorrected assumptions — and that the universe's true trajectory, and perhaps its ultimate fate, remains an open question. The dispute, unresolved between serious scientists examining the same evidence, reminds us that even the grandest conclusions rest on the fragile scaffolding of interp