Satellite Glint

Satellite glint is a brief, bright flash produced when sunlight reflects directly off a satellite's flat, mirror-like surface — typically a solar panel or antenna — at exactly the angle needed to bounce sunlight down toward a ground observer, appearing as a sudden, momentary flare in an otherwise unremarkable patch of sky. The phenomenon was, for years, dominated by a single well-known source: the original Iridium communications satellite constellation, whose distinctively angled antenna panels produced flares so bright, predictable, and precisely timed that dedicated hobbyist websites let observers look up the exact minute and location of an upcoming "Iridium flare" in advance, before the constellation was fully replaced with a non-flaring design starting around 2018. Other satellites, space debris, and even the International Space Station can produce similar glint effects under the right sun-observer-satellite geometry, though rarely with the same brightness or reliability the classic Iridium constellation offered. Glint remains a leading, well-established explanation for many single-flash "flash"-category UFO reports specifically because the effect is genuinely unpredictable to an observer who hasn't checked a satellite-pass schedule in advance, appearing without warning, lasting only a few seconds, and leaving no trailing light or sustained object behind — exactly the signature a startled witness typically describes.