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Credit & Copyright: Angel Yu
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
Yancheng,
China --
has been digitally processed to equalize the
Moon's brightness and exaggerate
the colors.
The gray color of the bottom right is
the Moon's natural color, directly illuminated by sunlight.
The upper left part of the Moon is not directly lit by the Sun since it is
being eclipsed -- it 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 blue
band is different -- its color is created by sunlight that has passed high through
Earth's atmosphere, where
red light is better absorbed
by ozone than
blue.
A total eclipse of the Sun will occur tomorrow but,
unfortunately, totality be
visible only near the
Earth's South Pole.
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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: