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Name: Katie
Status: other
Grade: other
Location: VA
Country: N/A
Date: 1/9/2005


Question:
What causes a double halo around the moon?


Replies:
Hi Katie!

The halos around the moon and the sun are caused by light reflecting through water droplets or ice crystals in the atmosphere. These halos form when light is separated into its various colours by the prism effect of the six sided ice crystals found in cirrostratus clouds. These clouds are very high up in the atmosphere, usually around twenty thousand to fifty thousand feet high. Light is bent by the ice at an angle of twenty two degrees, and so when they converge at the observer, he sees a ring of twenty two degree diameter around the sun or moon. The halo is pale, faintly coloured ring, usually with red on the inside and blue on the outside.

On rare occasions, a double halo can be seen, sometimes with faint spokes, and it is caused by light reflecting off water or ice. Thanks for asking NEWTON!

Mabel
(Dr.Mabel Rodrigues)



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