The lone planet KMT-2024-BLG-0816, one of many free-floating planets, was discovered when its gravity acted like a magnifying glass for a few hours. Passing in front of a distant star, the invisible body warped space like a glass marble, and boosted the background light. Thanks to a rare coincidence, the planet passed so close to the line of sight that telescopes could observe how the brightness of different parts of the stellar disk changed — the lens slid across its surface.

A faint stray light added to the mystery: it doesn't look like starlight, but could be the ghost of its former host. If confirmed, for the first time a lone planet will be seen together with its parent star — albeit separated by trillions of kilometers. Subsequent brightness measurements in different colors will test this hypothesis.