Credit & Copyright: Sigurdur H. Stefnisson
Explanation:
Aurorae usually occur high above the clouds.
The auroral glow is created when fast-moving
particles ejected from the
Sun impact air molecules high in the
Earth's atmosphere.
An
oxygen molecule, for example,
will glow in a green light when reacquiring an
electron
lost during a collision with a solar particle.
The lowest part of an
aurora will typically occur at 100 kilometers up, while
most clouds usually exist only below about 10 kilometers.
The relative heights of clouds and aurorae are shown clearly in the
above picture from
Iceland, where aurorae are relatively common.
Over the past weekend, one of the
largest sunspot groups ever recorded has been
associated with
explosive solar activity
and expansive terrestrial aurora displays.
Although in Earth's northern hemisphere
aurorae are usually seen only in the far north,
these aurorae
were so prevalent they were
imaged by a
continuous nighttime camera
operating in southern
Arizona!
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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:
aurora - polyarnoe siyanie - clouds - iceland - oblaka
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