Weeks after a story shot across the Web claiming that the imminent explosion of a nearby star would result in the appearance of a second sun in the sky — a story that was later debunked — two suns were caught on camera yesterday in China. The suns — one fuzzy and orange, the other a crisp yellow orb — appeared side-by-side, one slightly higher than the other.
What’s going on? Life’s Little Mysteries, a sister site to Space.com, asked Jim Kaler, the University of Illinois astronomer who squelched the excitement over the aforementioned exploding Betelgeuse and who has written books on the day and night sky. The double sun image is an effect of optical refraction, Kaler said, but it’s a “pretty darn rare” one, and one not fully explained by science.
“I doubt it’s been computer modeled,” he said. “There must have been some blob of atmosphere somewhere that caused this truly spectacular phenomenon, which in a sense is a mirage.” [Amazing Sun Photos From Space]
He goes on to state that the double or multiple image phenomena are produced by abnormal refraction, but that “it remains extraordinary that the images of the sun and moon were sharp and of the same size as the real sun and moon.”
“This is not a common optical phenomenon that we’re seeing here,” said Grant Perry, an atmospheric scientist at the University of Wisconsin Cooperative Institute for Satellite and Meteorological Studies. “I’m asking myself if this is an artifact of the lens, but if that were the case — if it’s reflections of the lens elements — then the images would move in relation to each other as the camera moves,” Perry said. “But that doesn’t happen.”
In terms of an optical explanation, he said, “You would have to assume it is particles of ice or something in the atmosphere aligned in such a way that they would refract the sunlight at that very small angle, but only in one direction. It would require some fairly peculiar characteristics.”
Several related atmospheric optical effects are fully explained by science. Sun dogs, sunset mirages, sun pillars and sun halos are all relatively common and well understood. But not this effect.
“It’s very intriguing,” said Kaler.