A Green Flash from the Sun
Credit & Copyright:
Juan Carlos Casado
Many think it is just a myth.
Others think it is true but its cause isn't known.
Adventurers pride themselves on having seen it.
It's a green flash from the Sun.
The truth is the
green flash
does exist and its cause is well understood.
Just as the setting
Sun disappears completely from view,
a last glimmer appears startlingly green.
The effect is typically visible only from locations with a low,
distant horizon, and lasts just a few seconds. A green flash is also visible for a rising
Sun, but takes better timing to spot.
A slight variant of this was caught in the
above photograph, where much of the
Sun was still visible,
but the very top appeared momentarily green. The
Sun itself does not turn
partly green, the effect is caused by layers of the
Earth's atmosphere acting like a prism.