At dusk on a late October night in 1408, something mysterious lit up the skies above China. Ming Dynasty astronomers who recorded the phenomenon wrote that its brightness was intense enough to last at least ten days. Back then, it was thought to be a “celestial guest”—a lost star that had wandered into that region of sky. The star was also described as “yellow in color,” most likely because yellow has positive associations. So, what kind of object had the Chinese court officials and literati really seen centuries ago?