Ever since a kid, I thought it was a myth, until I finally *thought* I saw it...
Whatever the case, it is a flash and does happen very quickily. Of course, looking at the sunset without any sunglasses on was never very appealing to me or my eyes
Good luck to all those green flash slueths out there.
Aloha
"Hilo pa`a ia ke aloha - I ka lino hilo pa walu - `A`ohe mea e hemo `ai - Me au `oe a mau loa"