[Bobby Shafto]

A month ago, I mentioned the so-called "green flash" as one of my "5 Characteristics of Sunset to Distinguish Between Flat Earth and Globe Earth.."  I meant to get back to this but it slipped my mind until RonJ brought it up today in another topic.

I used to hear about the "green flash" but even though I'd seen a lot of sunsets over the world's oceans, I had never witnessed a green flash. It wasn't until recently that I learned it was a real thing and not some mythical afterimage optical illusion. But I now understand what it is and have seen it, at least in video and photography imagery I've taken of the setting sun. And I also understand the explanation for it, but only in the context of a globe earth with an atmo-sphere. That explanation doesn't work for a flat earth with a planar atmo-layer. As such, I don't know how a flat earth model with an atmolayer explains this phenomenon.

The most comprehensive source (I think) for explaining the sun's Green Flash are a set of Web pages posted by San Diego State University's (former?) adjunct astronomy professor Dr. Andrew T. Young's page at https://aty.sdsu.edu/ . It's not very well organized, in my opinion, but rather a set of Web pages that seems as if it was composed and evolved over time, but there's a wealth of information not just about the green flash but of atmospheric effects on optics. It's a resource that's been very helpful for me in understanding the visual effects of atmospheric refraction, which for me had previously been limited to anomalous effects on radar and HF/UHF/EHF communications systems.

As explained in Dr. Young's pages, it's a complex combination of light extinction, diffusion (scattering) and astronomical refraction. It's this latter essential element that is absent in a flat earth/atmolayer model.

In a flat earth model that incorporates EAT, light bending up and away from the surface of the earth could cause the requisite refraction, but it would cause the green flash to appear on the bottom of the setting sun, not the top.

Light from the sun needs to be refracted downward along distances much greater than those required to produce terrestrial mirages. At least that's the mechanism as it is explained for an atmoSPHERE. If it can work through an atmoLAYER, and without ignoring other claimed explanations for varous sun set phenomena in a flat earth model, I'd like to invite that discussion.

[RonJ]

Yes, the green flash is real.  I've personally witnessed it on a couple occasions far out to sea.  You can see it at sun set and also at sun rise.  Sun rise is more difficult because you have to have access to something like a Nautical Almanac so you can see the exact time and azimuth that the sun will rise for your position and then be watching very carefully at that point on the horizon because you will only see the green flash for an instant and it will then go away, replaced by just the tip of the rising sun.  At sunset it's a lot easier as all you have to do is watch as the sun goes down over the horizon and you will sometimes see a flash just when the last little bit is going under.  The weather conditions have to be favorable for you to see something and you will only see it for an instant. 

[Bobby Shafto]

I've watched a lot of over-water sunsets: most from the California Pacific Coast, but also from Key West, Panama, Philippines, Thailand, Diego Garcia, Margaret River W.A. and from the flight deck of aircraft carriers in the North Arabian Sea, the Luzon Straits, South Pacific, South China Sea and Gulf of Alaska.

But try as I may, I've never been able to witness a "green flash" with my own eyes. I still haven't.

I've only been able to capture it with long focal length photography and video. And until I started seeing pictures of the phenomenon, I had the impression that it really was only visible at that last instant before the sun disappeared. But that may be the only point when the human eye can see it, but a camera lens will capture it throughout the sunset process, depending on atmospheric conditions.



This is a good picture - it's not one I took -- showing the sun in a state about 2 minutes before sunset is complete. The upper and lower limbs of the sun are showing different effects that whatever earth model you ascribe too must be able to explain both simultaneously. I think a globe earth model does. I don't know of a way for a flat earth model to accomplish that, at least based on what I've seen so far.

[Dr Van Nostrand]

I've spent a lot of time on the ocean and had been told about the green flash. But it was years before I actually got to see it in person and I was actually starting to think it was a snipe-hunting myth. When I finally got to see it, I was off shore near the Caribbean (South Atlantic) island of Saba and it looked nothing like I had imagined (pre Youtube era.)

The conditions had to be just right and you had to be looking at the right spot at the right time.  I could see that if someone didn't want to acknowledge the reality of the green flash, it is easy to ignore. Hoaxing a green flash video would be easier that hoaxing space travel videos.

[Bobby Shafto]

... I was actually starting to think it was a snipe-hunting myth.

Same here. Or, if I was accepting that it was real, I was sure it was an after-image illusion, like staring at a red dot for a minute and then looking at a white background and seeing a green dot.

Interestingly, here's an image taken of the moon doing the same trick but instead of a shorter wavelength color on the upper limb, it's a longer wavelength color on the lower limb.



I've never seen that before, but then again, I've never actually personally witnessed moonrise/moonset over a low-horizon.

[Bobby Shafto]

Another green flash yesterday evening.

This shouldn't happen if light is bent upwards.

[RonJ]

Great job!   The picture is typical of what I would see while mid-ocean going to Asia.  It also shows that there's curvature of the earth.

[Dr David Thork]

The sun is a ball moving very very fast through the upper atmoplane on a flat earth (exoplane). Its only 800 miles up.

I would expect a green flash from something moving so fast when the static in the air is high. It is called St Elmo's fire. The earth doesn't need to be round for that to happen.



Inb4 Wouldn't the sun create sonic booms at the equator? Answer ... no, the air is too thin much like satellites don't heat up in RE explanations.

[Bobby Shafto]

Found this posted in response to a similar challenge to "flat earth theory" way back in 2008.

"Why do we need to bother creating a theory for this phenomenon when we already know that the earth is flat?"

Not very zetetic.



In the top graphic, the atmosphere refracts sunlight when the sun is near the horizon, causing the sun to appear higher than it actually is. But this direction of refracted light (toward denser medium nearer the surface of earth) is also why the dispersion of green-wavelength light can appear on the upper rim of the setting sun.

In the middle graphic, this would work the same in a flat earth atmolayer. As the sun recedes, it penetrates greater lengths of denser air, bending it toward the earth's surface. That could great "green flash" phenomena too, but it would (like the globe earth) cause the sun to appear higher than it actually is.

However, a common explanation for why the sun appears to set on a flat earth even though it never actually dips below the surface plane of earth is that atmolayer effects cause the sun to appear lower than it actually is. That would require sunlight to refract/bend in the opposite direction, tending away from the surface of earth as depicted in the third diagram. But that's opposite of how refraction would work, unless the atmolayer actually gets denser with altitude.

Whatever the mechanism, if light actually bends away from the earth to cause the sun to appear to sink, then a different explanation for the green flash phenomenon is necessary. Because in that situation, the green flash -- if it would occur at all -- would be at the lower limb of the sun.

Essentially, a flat earth model isn't internally consistent if claiming refraction as the reason for the sun's reaching low elevation (and for the "sunken ship effect") while also adopting the atmospheric refraction/dispersion explanation for the "green flash" phenomenon as being also true for a flat earth atmolayer. The two explanations are in contradiction of each other. 

[RonJ]

I would expect to see some St. Elmo's fire as well under certain circumstances.  I've personally witnessed the phenomenon both at sea on ocean going ships and on aircraft as well.  Of course your explanation for the green flash on the sun is erroneous.  St. Elmo's fire requires a atmosphere and plenty of air.  Are you then saying that you have an atmosphere above the flat earth at 800 miles up?  Of course you can claim that there is, but then be ready to defend the atmospheric pressure on the earth's surface vs the density of air.  Are you ready for a discussion with just verifiable facts and no BS? 

[George Jetson]

This is very, very weak evidence for a globe.  Direct observations of the earth's surface show zero curvature therefore there must be some FE explanation for this phenomenon.  This phenomenon is so obscure that FErs generally haven't dealt with it, but I'm sure that an explanation could be found if we put our heads together.  I haven't really looked at it yet.

 Here's a Youtube video for good measure: 

https://www.youtube.com/watch?v=JaxpXwqRgXQ

[stack]

This is very, very weak evidence for a globe.  Direct observations of the earth's surface show zero curvature therefore there must be some FE explanation for this phenomenon. 

Here's a simple/good explanation why:

This phenomenon is so obscure that FErs generally haven't dealt with it, but I'm sure that an explanation could be found if we put our heads together.  I haven't really looked at it yet.

 Here's a Youtube video for good measure: 

https://www.youtube.com/watch?v=JaxpXwqRgXQ

As for the green flash, the video you posted presumes a solid glass dome-like paperweight is pressed firmly down on top of a flat earth.

[George Jetson]

This is very, very weak evidence for a globe.  Direct observations of the earth's surface show zero curvature therefore there must be some FE explanation for this phenomenon. 

Here's a simple/good explanation why:

This phenomenon is so obscure that FErs generally haven't dealt with it, but I'm sure that an explanation could be found if we put our heads together.  I haven't really looked at it yet.

 Here's a Youtube video for good measure: 

https://www.youtube.com/watch?v=JaxpXwqRgXQ

As for the green flash, the video you posted presumes a solid glass dome-like paperweight is pressed firmly down on top of a flat earth.

This thread isn't about arguing about whether or not there is a curve.  I wasn't even referring to just visually inspecting the horizon (which of course shows no visually detectable curve and wouldn't even if the earth were round at the agreed upon dimensions) but observation of distant objects, etc.  I brought that up to make the point that direct observations of the Earth should trump indirect evidences like the green flash.  It is to commit an affirming the consequent fallacy to claim that because a phenomenon has a RE explanation that satisfies you that therefore the RE must be true whereas the strongest FE claims (like the demonstrations that Earth has zero detectable curvature) by their very nature admit no RE explanation.  It is the burden of proof of the one who makes the positive claim that the green flash proves RE to not only supply the RE explanation but to prove that no FE explanation is possible. As for the video, it isn't perfect but it's a starting point.  It shows a green-flash like phenomena on a scale that FErs can roughly agree on.  Bobby presumes that all Flat Earthers believe in an "atmosplane" but many believe in a dome.

[stack]

This thread isn't about arguing about whether or not there is a curve.

It is actually, when you break it down: Atmosphere versus atmoplane.

I wasn't even referring to just visually inspecting the horizon (which of course shows no visually detectable curve and wouldn't even if the earth were round at the agreed upon dimensions) but observation of distant objects, etc. 

You were and still are.

I brought that up to make the point that direct observations of the Earth should trump indirect evidences like the green flash. 

I'm not following your trumping logic. Seems to be a fairly direct observation of the sun as it rises or sets from the vantage point of earth.

It is to commit an affirming the consequent fallacy to claim that because a phenomenon has a RE explanation that satisfies you that therefore the RE must be true whereas the strongest FE claims (like the demonstrations that Earth has zero detectable curvature) by their very nature admit no RE explanation.  It is the burden of proof of the one who makes the positive claim that the green flash proves RE to not only supply the RE explanation but to prove that no FE explanation is possible. As for the video, it isn't perfect but it's a starting point.  It shows a green-flash like phenomena on a scale that FErs can roughly agree on. 

I wouldn't go so far as to say the green flash proves a globe. But I would say that there is an RE explanation for it that is satisfactory to me and it is predicated on an atmosphere. The question is, how does the green flash phenomena manifest itself on a flat earth?

As to video, if shining a penlight through a hunk of glass replicates an earth/sun phenomena to FEr satisfaction, that speaks volumes.

Bobby presumes that all Flat Earthers believe in an "atmosplane" but many believe in a dome.

Can't speak for Bobby, but isn't the dome covering the atmoplane, so to speak?

[Bobby Shafto]

This thread isn't about arguing about whether or not there is a curve.

Seeing as how I initiated the discussion proposing that the "green flash" is a distinctive feature of a globe earth with an atmosphere and invited discussion about how such a phenomenon can be explained on a flat earth with an atmolayer, I'd say this thread is about whether there is or isn't "curve."

The phenomena of the sun reaching (and sinking behind) the horizon and also being able to exhibit a green flash are consistently explicable by a globe model with an atmosphere.

In a flat earth model, you can have a green flash, but then there is no explanation consistent with the green flash to explain the sun reaching (and appearing to sink behind) a horizon. Or, you can have a curved/refracted light explanation for why the sun appears to reach and set at a horizon, but then that defeats the green flash explanation. There is no flat earth model that I've seen yet proposed that can explain both without contradiction.

Dome or no dome.

The prism effect of that glass half sphere is exhibiting light refraction and dispersion, but isn't producing an image mimicking the setting sun with a green flash. If you believe that glass medium models a firmament containing an atmolayer or that the dome IS the atmolayer, then it should be able to produce the illusion of a setting sun by a light source above the dome, from the perspective of an observer at the base, and simultaneously create the prism effect with the shorter wave length colors on top and the longer wavelength colors on the bottom, as oriented to the base of the dome.

If you can do that, then you've answered the challenge. I don't think it can be done. The bending of light necessary to make the light source appear to be lower toward the base is the opposite of what would make the prism'ed green dispersion of color appear on the top of the light source.

[Bobby Shafto]

Bobby presumes that all Flat Earthers believe in an "atmosplane" but many believe in a dome.

Can't speak for Bobby, but isn't the dome covering the atmoplane, so to speak?

Bobby doesn't presume anything about what flat earther's believe regarding a dome. 
Bobby leaves it to the flat earther to devise a flat earth model to solve the riddle, and leaves it up to the flat earther to decide whether or not a dome helps answer the question.

[AATW]

The sun is a ball moving very very fast through the upper atmoplane on a flat earth (exoplane). Its only 800 miles up.

Can you show me the evidence for that? How was that 800 miles worked out and tested experimentally?

[totallackey]

A month ago, I mentioned the so-called "green flash" as one of my "5 Characteristics of Sunset to Distinguish Between Flat Earth and Globe Earth.."  I meant to get back to this but it slipped my mind until RonJ brought it up today in another topic.

I used to hear about the "green flash" but even though I'd seen a lot of sunsets over the world's oceans, I had never witnessed a green flash. It wasn't until recently that I learned it was a real thing and not some mythical afterimage optical illusion. But I now understand what it is and have seen it, at least in video and photography imagery I've taken of the setting sun. And I also understand the explanation for it, but only in the context of a globe earth with an atmo-sphere. That explanation doesn't work for a flat earth with a planar atmo-layer. As such, I don't know how a flat earth model with an atmolayer explains this phenomenon.

The most comprehensive source (I think) for explaining the sun's Green Flash are a set of Web pages posted by San Diego State University's (former?) adjunct astronomy professor Dr. Andrew T. Young's page at https://aty.sdsu.edu/ . It's not very well organized, in my opinion, but rather a set of Web pages that seems as if it was composed and evolved over time, but there's a wealth of information not just about the green flash but of atmospheric effects on optics. It's a resource that's been very helpful for me in understanding the visual effects of atmospheric refraction, which for me had previously been limited to anomalous effects on radar and HF/UHF/EHF communications systems.

As explained in Dr. Young's pages, it's a complex combination of light extinction, diffusion (scattering) and astronomical refraction. It's this latter essential element that is absent in a flat earth/atmolayer model.

In a flat earth model that incorporates EAT, light bending up and away from the surface of the earth could cause the requisite refraction, but it would cause the green flash to appear on the bottom of the setting sun, not the top.

Light from the sun needs to be refracted downward along distances much greater than those required to produce terrestrial mirages. At least that's the mechanism as it is explained for an atmoSPHERE. If it can work through an atmoLAYER, and without ignoring other claimed explanations for varous sun set phenomena in a flat earth model, I'd like to invite that discussion.

It would be incumbent upon you to clearly demonstrate why it cannot appear on flat earth first.

While feeling no obligation to point out the obvious, simply stating,"...it cannot," earns you the perfunctory, "...yes it can."

EAT is not even complete and you are going to post a conclusion as if it is?

[Bobby Shafto]

It doesn't matter what the mechanism is that is causing the bending of light.
Doesn't matter if earth is flat or globe.
If light is being bent in the opposite direction - upwards away from earth- green flash won't be on top of an apparent setting (or rising) sun.

If you want your green flash and an upward bending of light to explain sun setting in a flat earth model, you need a new explanation for the phenomenon and not the one we currently have that is compatible with globe earth.

[rpt]

I brought that up to make the point that direct observations of the Earth should trump indirect evidences like the green flash.

It doesn't work like that. You can't say that because you can see no curvature then you can discount all evidence of curvature. If you are promoting a scientific model for something then you need to be able to explain all evidence.

It is the burden of proof of the one who makes the positive claim that the green flash proves RE to not only supply the RE explanation but to prove that no FE explanation is possible.

No it's not. If RE has an explanation for an observation then that is more weight in favour of RE. If supporters of FE can explain it, then that is weight in favour of FE.

RE can explain all these observations, FE cannot. So the weight of evidence is in favour of RE. In fact, the weight is so in favour of RE that is an accepted scientific fact.