Legend goes that just as the sun sets below the horizon, a flash of green light appears to kiss the day goodbye. Sailors say that when the flash appears, it means a soul has crossed over. Jules Verne wrote that those who witnessed it could no longer be deceived because he could read the thoughts of others. Admiral Byrd supposedly saw one that lasted 35 minutes. For a full record of sightings, see here. But is this really stuff of legend or a real phenomenon in the sky?