Dr. Brian Keating

The Earth's atmosphere is not only made of oxygen. It actually has a lot of particulates. And it's because of those particulates, a lot of them come from dust and a lot of them come from volcanoes and a large amount now comes from human-made sources, pollution and so forth. The more optical depth, the more path length that you look through, the more scattering of the sun's light occurs.

The Earth's atmosphere is not only made of oxygen. It actually has a lot of particulates. And it's because of those particulates, a lot of them come from dust and a lot of them come from volcanoes and a large amount now comes from human-made sources, pollution and so forth. The more optical depth, the more path length that you look through, the more scattering of the sun's light occurs.

The Earth's atmosphere is not only made of oxygen. It actually has a lot of particulates. And it's because of those particulates, a lot of them come from dust and a lot of them come from volcanoes and a large amount now comes from human-made sources, pollution and so forth. The more optical depth, the more path length that you look through, the more scattering of the sun's light occurs.

When scattering occurs, the longer wavelength light more easily penetrates through dust, smog particles, even glass. So that goes through easier. And the short wavelengths, comparable to the intermolecular spacing of the smog, the dust, the gas, and the atmosphere, the oxygen, scatters much more efficiently. And so that gets scattered out of the beam of light from the sun.

When scattering occurs, the longer wavelength light more easily penetrates through dust, smog particles, even glass. So that goes through easier. And the short wavelengths, comparable to the intermolecular spacing of the smog, the dust, the gas, and the atmosphere, the oxygen, scatters much more efficiently. And so that gets scattered out of the beam of light from the sun.

When scattering occurs, the longer wavelength light more easily penetrates through dust, smog particles, even glass. So that goes through easier. And the short wavelengths, comparable to the intermolecular spacing of the smog, the dust, the gas, and the atmosphere, the oxygen, scatters much more efficiently. And so that gets scattered out of the beam of light from the sun.

The sun's light, though, actually peaks slightly in the green. We don't actually notice this because our eyes are – and we're used to thinking of it as very yellow. And the reason for this can be substantiated by – Night vision glasses, what color is the light coming in? It's green, right? The amplified versions of these things. Why? Because your eye is very sensitive to green light.

The sun's light, though, actually peaks slightly in the green. We don't actually notice this because our eyes are – and we're used to thinking of it as very yellow. And the reason for this can be substantiated by – Night vision glasses, what color is the light coming in? It's green, right? The amplified versions of these things. Why? Because your eye is very sensitive to green light.

The sun's light, though, actually peaks slightly in the green. We don't actually notice this because our eyes are – and we're used to thinking of it as very yellow. And the reason for this can be substantiated by – Night vision glasses, what color is the light coming in? It's green, right? The amplified versions of these things. Why? Because your eye is very sensitive to green light.

It's even more sensitive to green light than the yellow light. And that's because the sun, which is what we've evolved to adapt to, being most sensitive to sunlight, is more greenish than yellow.

It's even more sensitive to green light than the yellow light. And that's because the sun, which is what we've evolved to adapt to, being most sensitive to sunlight, is more greenish than yellow.

It's even more sensitive to green light than the yellow light. And that's because the sun, which is what we've evolved to adapt to, being most sensitive to sunlight, is more greenish than yellow.

Exactly, 100% right. So at that green flash, at that moment of green flash, you're seeing two things. One is the sensitivity of the human eyes, slightly maximized to that, but that doesn't explain why photographs see it as well. And the other reason is that most of the yellow light and the sunlight is getting scattered away.

Exactly, 100% right. So at that green flash, at that moment of green flash, you're seeing two things. One is the sensitivity of the human eyes, slightly maximized to that, but that doesn't explain why photographs see it as well. And the other reason is that most of the yellow light and the sunlight is getting scattered away.

Exactly, 100% right. So at that green flash, at that moment of green flash, you're seeing two things. One is the sensitivity of the human eyes, slightly maximized to that, but that doesn't explain why photographs see it as well. And the other reason is that most of the yellow light and the sunlight is getting scattered away.

And so you're mainly seeing that green light, but you're only seeing it at the point of maximum scattering, which occurs exactly when the sun crosses the horizon.

And so you're mainly seeing that green light, but you're only seeing it at the point of maximum scattering, which occurs exactly when the sun crosses the horizon.

And so you're mainly seeing that green light, but you're only seeing it at the point of maximum scattering, which occurs exactly when the sun crosses the horizon.

I don't think that's in disagreement. I think that might explain the amplification that we see, but then it doesn't explain why you'd see it in a photographic emulsion, right? There's nothing biological about it.

I don't think that's in disagreement. I think that might explain the amplification that we see, but then it doesn't explain why you'd see it in a photographic emulsion, right? There's nothing biological about it.