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Астронет: Астрономическая картинка дня Радужное облако над Францией http://www.variable-stars.ru/db/msg/1197588/eng |
Credit & Copyright: Michael Koch
Explanation:
Why would a cloud appear to be different colors?
A relatively rare phenomenon known as
iridescent clouds can show unusual colors vividly or a whole
spectrum of colors simultaneously.
These clouds are formed of small
water droplets of nearly uniform size.
When the Sun is in the
right position and mostly hidden by thick clouds,
these thinner clouds significantly
diffract sunlight in a nearly coherent manner,
with different colors being deflected by different amounts.
Therefore, different colors will come to the observer
from slightly different directions.
Many clouds start with uniform regions that could show
iridescence but quickly become too thick, too mixed,
or too far from the Sun to exhibit striking colors.
Pictured above, an iridescent cloud was photographed near Cannes,
France last month.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.