Green Flash During A Sunset | Is It True?

The Mythical Green Flash during a sunset. It was first made popular by Jules Verne in an 1882 novel LE RAYON VERT(THE GREEN RAY) and it is still leaking into pop culture through an occasional pirate movie sequel. Except, it is not actually a myth.

That’s weird right. usually, we are debunking things people think are true, not the other way around.
But the green flash is a real optical phenomenon and it doesn’t just happen right after the sun sets. We can see it right before sunrise, too. We can see it from any altitude and from anywhere in the world. But the catch is You have to have the right conditions.

You might think that the Earth’s air is pretty uniform, minus the occasional puffy cloud or two. But there are a bunch of invisible layers in the atmosphere, each with slightly different temperatures and densities. As sunlight might travels from one layer to another, the sunlight refracts or bends, just a little bit. It’s the same principle that makes your straw look like it’s bent below the water in your glass. But the amount of refracting depends on the wavelength and therefore, the colour of the light.

So the different colours end up separating out from the white sunlight that enters the atmosphere. The most obvious way to see this separation is in a rainbow, although that comes from a much more dramatic change in density from air to water droplet, so it is a much more obvious effect. The shorter the wavelength, the more the light is refracted. Bluer light has a shorter wavelength, so as the sun sets, those shades will stay visible longer because they can be bent further around the horizon.

It’s kind of weird to think about, but basically, the red image of the sun sets first, followed by orange, yellow, green, blue, indigo and violet. There is a second or two delay between the last visible red sunlight and the violet. It’s not a lot of time, but it is enough if you know when and where to look. It works exactly in the opposite direction too with sunrises.

But if the blue and violet shades of the sun are also above the horizon, why are these flashes green?

Well, shorter wavelengths of light are scattered more after colliding with molecules in the air that’s why the sky is blue. But That also means violet and blue light are more likely to be scattered away from your line of sight, so you see the sun as green. If the air is super clear you can see blue flashes. If air is super hazy, enough green might be scattered to make the flash look yellow instead.

But there is a reason we don’t see a flash with every sunrise and sunset is that this refraction is not enough for us to actually be able to see the flash with our own eyeballs. The physical separation between the different colours is not large enough. So we also need a mirage to magnify the effect.

Mirages are just multiple images formed by atmospheric refraction. You might think one of those images is real and the rest are fake, but that’s not the case. They all come from a single source.

The Mirage, in this case, looks like a second sun. You know those pictures of sunsets where it looks like the sun grows a little stand at the bottom! That’s actually two mirage images overlapping and it is what allows us to see green flashes. During sunsets, there is also a physiological component that can amplify the effect. When you look at a reddish sunset, the receptors in your eyes that detect red light get so used to being activated that when the source goes away, everything looks more green than it really is.

The above phenomena do not happen in sunrises, because there is no red sun to look at, the green rises above the horizon first. While Green Flashes can theoretically be seen anywhere on Earth at any time of year, they are best spotted above an unobscured horizon where the air is clean and relatively stable. Which is probably why so many stories of them come from people on boats.

So if you find the right spot, you might just get a glimpse of what Jules Verne described as “The true green of Hope.” So The Science Thinkers Do You Have Any Dought Regarding Above Topic? Then Ask Us On Comment Section And Always Stay Curious. 

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