Credit & Copyright: Tamas Ladanyi
(TWAN)
Explanation:
In this serene night skyscape,
the Milky Way's graceful arc stretches over prominent
peaks in the Italian Alps known as Tre Cime di Lavaredo.
A 180 degree wide-angle panorama made in four exposures on
August 24, the scene does look to the north and the sky is suffused
with an eerie greenish light.
Still, the subtle glowing bands are
not aurorae, but airglow.
Unlike aurorae 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, and
found around the globe.
The chemical energy is provided by the Sun's extreme ultraviolet
radiation.
Like aurorae, the greenish hue of this airglow does originate
at altitudes of 100 kilometers or so dominated by
emission from excited oxygen atoms.
More easily seen
near the horizon, airglow keeps the
night sky from ever being
completely dark.
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 |
Yanvar' Fevral' Mart Aprel' Mai Iyun' Iyul' Avgust Sentyabr' Oktyabr' Noyabr' Dekabr' |
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
|
Publikacii s klyuchevymi slovami:
Milky Way - Mlechnyi Put' - himicheskie reakcii - atmosfernye yavleniya
Publikacii so slovami: Milky Way - Mlechnyi Put' - himicheskie reakcii - atmosfernye yavleniya | |
Sm. takzhe:
Vse publikacii na tu zhe temu >> | |
