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Астронет: Астрономическая картинка дня Волны свечения атмосферы над Тибетом http://variable-stars.ru/db/msg/1320642/eng |
Credit & Copyright: Jeff Dai
Explanation:
Why would the sky look like a giant target?
Airglow.
Following a giant thunderstorm over
Bangladesh
in late April, giant circular ripples of glowing air appeared over
Tibet,
China, as
pictured above.
The unusual
pattern
is created by atmospheric
gravity waves, waves of alternating air pressure that can grow with height as
the air thins, in this case about 90 kilometers up.
Unlike auroras powered by collisions with energetic charged
particles and seen at high latitudes, airglow is due to
chemiluminescence,
the production of light in a chemical reaction.
More typically seen near the horizon,
airglow keeps the night sky from
ever being completely dark.
Now Available:
APOD 2015 Wall Calendars
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.