Starship Asterisk*

The lower blue part of the Belt is just the twilight sky rising (or setting). In the evening I sometimes call it "nightrise". So yeah, it is only lit indirectly, by light that has scattered from air still lit by the Sun directly. So every moment of twilight involves some combination of di...

The Belt of Venus illustrates this. The upper pink part is directly lit by the Sun. The lower blue part is only scattering light from other parts of the sky. When I think of Descartes on clear and distinct ideas, where “distinct” perceptions are "sharply separated from all other perceptions&qu...

It doesn't look ozone blue to me. I'd say it's dominated by Rayleigh scattered sunlight, which itself is scattered off the illuminated part of the sky. I see, perhaps because the Belt of Venus is visible shortly before sunrise or after sunset, during civil twilight, and ozone blue occurs closer to ...

The Belt of Venus illustrates this. The upper pink part is directly lit by the Sun. The lower blue part is only scattering light from other parts of the sky. Regarding the lower blue part, which is the Earth's shadow, I wonder if the blue color is not a function of Rayleigh scattering but instead C...

I wonder if this Wikipedia article on Sky brightness makes sense -- it seems to that there is both direct and indirect sunlight in the sky at twilight -- "Indirectly scattered sunlight comes from ... the atmosphere itself .... the Sun has just set but still illuminates the upper atmosphere dire...

The color green does not exist outside our human eyes and brains. It is our eyes and brains that "create" the color green. Also then should be the case regarding the sun's green flash, it is an optical phenomenon, as our eyes and brains also create the color green of the sun's green flash...

It is why earthly sunsets are never green. ...why atmospheric absorption of colors would prevent sunsets on the Earth from ever looking green. "Why are earthly sunsets never green?" seems an interesting topic to compare with Northern Lights, so prevalent at the moment -- the sun's charged...

Chris Peterson wrote: ↑Fri May 10, 2024 12:41 pm And evolution doesn't favor organisms that don't die and make room for future generations.

Yes, it is a very powerful theory, evolution, to be able to derive such a conclusion, for it apparently would apply to every living organism, or are there any exceptions?

All I can say is that purple light triggers a response from both the blue-sensitive and the red-sensitive rods in our retinas. Consider this color, ███ . The (rgb) values of this particular color is, r = 123 , g = 0, and b = 222 . So purple, at least as far as our eyes are concerned, is indeed a mi...

Given a well understood mechanism for creating blue light in the sky, and a well understood mechanism for creating red light in the sky, and well understood mechanisms of reflection and scatter, it would be difficult to explain if we didn't regularly see purple! I think we are indebted to Edward Ol...

Peter, I think you are right that the anti-twilight sky phenomenon, the Belt of Venus, can make the sky take on hints of a purple color. Ann Ann, I was following up on hints of a purple color and the anti-twilight sky phenomenon, the Belt of Venus, and I came across "afterglow," at the mo...

Or if they're just into shadow, they may still pick up the red light reflected from clouds even further west. Or they may be in shadow, in which case they are likely to look blue (which some people see as purple) because they are reflecting blue sky. Chris, I don't understand to which shadow you ar...

Peter, you wrote about the purple color of the upper sky. As I said, I have never observed purple color in the sky, except on those rare occasions when pink clouds at sunset or sunrise momentarily seem to take on a purplish-pink hue. Otherwise, I've never seen it. Ann, thanks for putting me in the ...

Thanks to all of you who looked at my post! Please let me know -- no one wants to reply to my question because: 1. It is a such difficult question, impossible, I've asked a question that has stumped all viewers! (unlikely!) 2. On the contrary, my question is quite idiotic and incomprehensible, the q...

Very impressive photograph, both aesthetically and conceptually. My question is, the sun is observable and approximately the same shade of orange is observable both on the horizon and on the cloud above, but the moment the sun is below the horizon, most likely the horizon will remain orange color fo...

Hello all -- I'm trying to understand colors of the sky at twilight. I'm not in the field of physics, but I've tried to grasp some concepts, which I first briefly note, and then pose some questions. Any feedback would be greatly appreciated. 1. Attempt at basic understanding. The blue light waves of...