Three suns shone over China: Illusion or magic?

Sundogs in Fargo, North Dakota. Taken February 18th, 2009

On 1st November 2013, friday, three suns shone over the inner region of Mongolia in northern China. Well, contrary to the rumours, it was neither indications of doomsday nor magic. It was an atmospheric phenomenon known as "Phantom Sun" or "Sun dog". Its scientific name is Parhelion which means beside the sun.

It is an atmospheric phenomenon that creates bright spots of light in the sky, often on a luminous ring or halo on either side of the sun. Sundogs may appear as a colored patch of light to the left or right of the sun, 22° distant and at the same distance above the horizon as the sun, and in ice halos. 

How do they look?

Here's a video of the sun dogs observed in Mangolia on Friday.

How are they formed?

Phantom suns are commonly made by the refraction of light from hexagonal ice crystals (which are present in the high and cold cirrus clouds) which drift in the air at low levels. These crystals act as prisms, bending the light rays passing through them with a minimum deflection of 22°. If the crystals are randomly oriented, a complete ring around the sun is seen — a halo (as seen in the image below).

But often, as the crystals sink through the air, they become vertically aligned, so sunlight is refracted horizontally — in this case, sundogs are seen.

As the sun rises higher, the rays passing through the crystals are increasingly skewed from the horizontal plane. Their angle of deviation increases, and the sundogs move further from the sun. However, they always stay at the same elevation as the sun.