Астронет: Астрономическая картинка дня Радужные облака над Тамсерку http://variable-stars.ru/db/msg/1316834/eng |
Credit & Copyright: Oleg Bartunov
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.
The above iridescent
cloud
was photographed in 2009 from the
Himalayan Mountains in
Nepal, behind the 6,600-meter
peak named
Thamserku.
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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.