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Credit & Copyright: Zixiong Jin
Explanation:
What causes a blue band to cross the Moon during a lunar eclipse?
The blue band is real but usually quite hard to see.
The featured HDR image of last week's lunar eclipse, however -- taken from
Norman,
Oklahoma (USA)
-- has been digitally processed to exaggerate
the colors.
The gray color on the upper right of the top lunar image is
the Moon's
natural color, directly illuminated by sunlight.
The lower parts of the Moon on all three images
are not directly lit by the Sun since it is
being eclipsed -- it is in the
Earth's shadow.
It is faintly lit, though, by sunlight that has passed deep through
Earth's atmosphere.
This part of the Moon is red -- and called a
blood Moon -- for the same reason that Earth's sunsets are red:
because air scatters away
more blue light than red.
The unusual purple-blue band visible on the upper right of
the top and middle images is different -- its color is augmented
by sunlight that has passed high through Earth's atmosphere, where
red
light is better absorbed by
ozone than blue.
Celestial Surprise:
What picture did APOD feature on your birthday? (post 1995)
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NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: lunar eclipse
Publications with words: lunar eclipse
See also: