Tabby's Star: The Flickering Sun That Made Astronomers Say the A-Word

2026-07-07 · Signals & Sounds · 9 min read

It began, as the best modern mysteries often do, with amateurs staring at a graph. Between 2009 and 2013, NASA's Kepler space telescope held its unblinking gaze on roughly 150,000 stars in a single patch of sky near the constellation Cygnus, hunting for the faint, regular winks that betray a planet crossing in front of its sun. The dimming is minuscule; even a giant the size of Jupiter blocks only about one percent of its star's light. The data were too vast for scientists alone, so a project called Planet Hunters invited the public to scan the light curves by eye. And it was these volunteers, ordinary people at their keyboards, who kept circling one star and scrawling the same baffled comments. The star was KIC 8462852, an otherwise unremarkable object about 1,470 light-years away, and its light was not behaving like anything in the catalog.

Instead of a shallow, clockwork dip repeating on a fixed schedule, its brightness was collapsing in ragged, asymmetric plunges, by 15 percent on one occasion and by a staggering 22 percent on another, at intervals that followed no discernible rhythm and lasted anywhere from days to weeks. To grasp how absurd that is, remember that a Jupiter causes a one-percent dip. Whatever was crossing this star was blocking nearly a quarter of it, and doing so irregularly, in shapes no orbiting sphere could produce. A planet makes the same tidy dip on the same rigid schedule, over and over, because it is a ball on a fixed orbit; this star's dips had no schedule and no symmetry, some plunging steeply and recovering slowly, others the reverse, as though the thing passing in front kept changing its shape. No known planet, and no ordinary configuration of matter, behaves that way.

Reader comments (0)