A Multiple Green Flash Sunset
Yes, but can your green flash do this?
A green flash at sunset is a
rare event that many Sun watchers pride themselves on having seen.
Once thought to be a myth, a
green flash
is now understood to occur when the Earth's atmosphere acts like both a
prism and a lens.
Different atmospheric layers create altitude-variable
refraction that takes light from the
top of the Sun and disperses its colors,
creates two images, and magnifies it in just the right way to make a
thin sliver appear green just before it disappears.
Pictured, though, is an even more unusual sunset.
From the high-altitude
Cerro Tololo Inter-American Observatory in
Chile one day last April,
the Sun was captured setting beyond an atmosphere with
multiple distinct thermal layers, creating several
mock images of the
Sun.
This time and from this location, many of those layers produced a
green flash simultaneously.
Just seconds after this multiple-green-flash event was caught by
two well-surprised astrophotographers, the Sun set below the clouds.