[Wneighbor]

What is "the green flash?"

Okay, you both shoulda known you were gonna have to splain it to me if you mentioned it.

[Ramius]

The 'green flash' is a phenomenon of sunset at sea in particular atmospheric conditions. Under some set of conditions (mainly really, really clear air, I think...) then just as the very last little bit of the sun disappears over the horizon at sunset there is sometimes a very bright and very brilliant bright emerald green flash of light.

It only lasts for a few seconds. But it often takes years at sea to finally see it. But it is there.

[Ramius]

It looks like this: