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Has Anyone Seen the Green Flash?

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  • Has Anyone Seen the Green Flash?

    Today I read an article about a supposed phenomenon that is rarely seen but is often used as an excuse for shots of tequila at lakeside bars and other sites near bodies of water. This phenomenon only occurs at sunset over lakes, and only rarely. Of course it occurs more often at the bars that offer free drinks for spotting it when it occurs(Tell me where it is, and I'll invite Alistair. He sees a green flash every night! Bring another round!)


  • #2
    I have once in the French West Indias. I t requiers a clear horizon on a large body of water. has to do with wave length and color spectrum. green being the last color that we see.

    ------------------
    George from Conyers Ga.
    Remember the early bird gets the worm, BUT it's the second mouse that gets the cheese.
    George from Conyers Ga.
    Remember
    The early bird gets the worm, BUT it's the second mouse that gets the cheese.

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    • #3
      yup, 20 years ago while sailing off Abaco Island. saw it very clearly and no alcohol was involved. we didn't drink when sailing and were going 24/7 so drinking had no role in it.

      I think it really needs a very large body of water, ie i live on the great lakes and have never heard people talk about the green flash on the lakes, only the ocean.


      [This message has been edited by Mcgyver (edited 01-21-2006).]
      .

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      • #4
        It's caused by the different refraction of different colors of light by the atmosphere. Just as in a prism a refracting medium will alter the path of light to a varying degree according to color.

        When the sun sets it is actually about 1/2 degree below the horizon when we see it as just setting. The refractive index of air is rather low so it doesn't "bend" the light much. The higher the frequency the more the light is bent.

        For the green flash to be seen requires a very clear and still atmosphere. Theoretically a blue flash would be possible as blue light is refracted even more than green. We don't see that as the atmosphere contains enough pollution to nearly completely filter out the blue wavelengths when the light takes such a long tangential path. Green is just barely able to make it through when conditions are perfect.

        It is usually seen only over the ocean because the air is less polluted when looking over the ocean to the west. This isn't just a matter of man made pollution but more so from smoke in the air. Smoke particles are just the right size to filter blue light and the red light isn't bent enough to be seen at the last moment when the flash occurs. That leaves green.

        [This message has been edited by Evan (edited 01-21-2006).]
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        • #5
          Back in the day just after the US Navy changed from using the wooden ships was on a WWII destroyer heading back to Nam. we were chacing the sunset. Caught a couple of glimpses of it in a couple of minutes time span. A course no alchol, Torpedeo juice were involed we had people doing pot. But I was not one of them at the time.

          ------------------
          Glen
          Been there, probally broke it doing that
          Glen
          Been there, probably broke it, doing that!
          I am not a lawyer, and never played one on TV!
          All the usual and standard disclaimers apply. Do not try this at home, use only as directed, No warranties express or implied, for the intended use or the suggested uses, Wear safety glasses, closed course, professionals only

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          • #6
            I doubt that the water comes into it. Lots of photos from a base at the south pole are floating around, and of course in that case water is nowhere near, just loads of ice. A clear view of the horizon helps. But I heard of a case of it appearing when the sun set behind a building in Los Angeles.

            The moon will give you green flashes too. It's not as commonly reported as a solar flash. Also sunset is the most likely time, but sunrise can work too.

            I've never run into it, myself.

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            • #7
              I have seen a few green flashes and other color flashes too, but it involved mushrooms everytime

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              • #8
                I am known locally as the pink flasher but I can't talk about it too much as my case comes up next week Alistair
                Please excuse my typing as I have a form of parkinsons disease

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                • #9
                  The water has nothing to do with it other than that the atmosphere to the west over a long stretch of ocean is a long distance from immediate sources of pollution. A very low horizon is also required which water provides.

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                  • #10
                    You need more Sun, Alistair.... then you can be the Tan Flasher. The have those on some beaches. Sun... Sun... that big yellow thing you see three days of the year up north - where you are at.....

                    --jr
                    dvideo

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                    • #11
                      We have a saying in Scotland SUN WHAT'S THAT Alistair
                      Please excuse my typing as I have a form of parkinsons disease

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                      • #12
                        Alistair How did they get you for flashing? You have to have something to flash first.
                        Don\'t ask me to do a dam thing, I\'m retired.
                        http://home.earthlink.net/~kcprecision/

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                        • #13
                          Alistair, a few years ago.

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                          • #14
                            That's not a fine young Lieutenant standing at attention at the barracks doors. No that's a tired old Sergent sitting on a couple of duffle bags.

                            I thought there would be a little more mystery about this green flash phenomenon, but you guys are really SHARP (I knew that!) The explanation makes perfect scientific sense to me and it comports to what I read. I'd love to see it for myself someday.

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                            • #15
                              I've never seen it either. It appears most often at the tropical latitudes. At those latitudes the sun sets more or less straight down on the horizon which helps to accentuate the seperation of the colors in time, hence the "flash".
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