Caelum Incognitum — The interactive encyclopedia of ufology
Colour-changing lights
Explanations & misidentifications
A bright star or planet low on the horizon, such as Sirius or Venus, twinkles and alternates red, green and white: the air, which disperses light, acts like a prism. This very misleading effect explains many accounts of a “multicoloured light” that seems to move or manoeuvre.