Green Flash from the Sun :: weather sunset

Many think it's 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. The Green Flash Definition and Description: The green flash is an atmospheric refractive phenomenon where the top edge of the sun will momentarily turn green. It is seen rarely by the naked eye, primarily because it requires specific conditions to occur, but also because it requires the observer to know what to look for. Despite the name, there is no "flash;" the event only lasts from a fraction of a second to at the longest, a few seconds. The Basic Cause: Refraction bends the light of the sun. The atmosphere acts like a weak prism, separating the light into diferent colors. Blue light is bent more strongly than red. But this refraction is very weak even at the horizon, which is why the sun isn't seen as being multi-colored in the daytime. The effect is magnified by the atmosphere, and at the horizon there is a lot of atmosphere between the sun and the viewer. Layering in the atmosphere causes an effect similar to a horizontal cylindrical lens: the separation of the color bands is exaggerated in the vertical direction. Conditions: The green flash is best observed when you have a clear view of the horizon, with no objects or pollution in the line of sight. Usually you need to be able to see a distance of several miles out, almost to the point where the curvature of the Earth defines the limit. Because of this, the green flash is most often reported by the ocean.