Supposedly, this is seen on a clear
day when the
sun sets. If you do see it, it'll be when the sun it just
disappearing, when you see its last
sliver of
light disappear. You see a small
green flash of
light. When I saw it, it wasn't a flash that filled the
sky, it was just a little sliver of green that slightly extended the size of the sliver of
yellow sun that was disappearing.
Explanatory excerpt from the NASA site, listed on the bottom:
The Sun itself does not turn partly green, the
effect is caused by
layers of the
Earth's
atmosphere acting like a
prism.
urls:
- pictures - < http://mintaka.sdsu.edu/GF/pictures.html >
- the main url to the above site - < http://mintaka.sdsu.edu/GF/ >
- nasa's picture/brief description - < http://antwrp.gsfc.nasa.gov/apod/ap970909.html >