Green flashes at the Poles
Q: Do they have green flashes
at the South Pole?
A: Yes. "...at the South [and North]
Poles, where there is one sunset per year that takes many days to occur, green
flashes and 'blue flashes' can last for many hours to days," says Russell
Schnell, Observatory Operations director at NOAA's Climate Monitoring &
Diagnostic Laboratory.
A green or blue flash is a
phenomenon where the atmosphere, acting as a prism, bends the Sun's rays at
sunset. This causes the top edge of the Sun to turn blue, for a moment since the
prism bends blue light the most. In extremely clear air, such as you find at the
poles, the top edge looks blue. Otherwise, blue light interacts more with the
atmosphere and scatters, causing the top edge to look green.
(Answered Aug. 30, 2002; updated Oct. 25, 2007)
Further Surfing:
NOAA/CMDL: South Pole
life
U of Chicago:
pictures of the South Pole's green flash
Click for printer version.
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