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General => Terragen Discussion => Topic started by: N-drju on September 10, 2017, 03:13:53 AM

Title: East and West
Post by: N-drju on September 10, 2017, 03:13:53 AM
Hello,

I was wondering... Is there any visible difference between sky and light colors during sunrise and sunset? I mean real world of course...

It is commonly thought that sunsets tend to be more reddish and orange-y. With an array of gold colors, but are they really?

Or is light color just the same at 7am and 7pm? Any scientific sources are welcome (if any).
Title: Re: East and West
Post by: Oshyan on September 11, 2017, 12:53:33 AM
Anecdotally speaking sunsets are more colorful and spectacular. Scientifically speaking, I don't have any evidence to site, but I think one can consider it logically and perhaps come to some general potential differences. What does the warmth of the sun through the day do to the amount of particulates in the atmosphere, for example? My guess is it increases them for a couple reasons. First, because of evaporation of volatiles due to heating, and second, due to rising of existing particles in the atmosphere as they are heated. Perhaps there are other mechanisms too. The greater the amount of particulates in the air, the redder the atmospheric scattering would tend to be (depending on particulate characteristics). You can logically contemplate other effects of the conditions of sunrise vs. sunset as well. Or... just find some real sources, if any studies have been done. I'm curious myself, but thought that the "thinking it through" approach might have benefit too...

- Oshyan
Title: Re: East and West
Post by: bobbystahr on September 11, 2017, 10:21:06 AM
Quote from: Oshyan on September 11, 2017, 12:53:33 AM
Anecdotally speaking sunsets are more colorful and spectacular. Scientifically speaking, I don't have any evidence to site, but I think one can consider it logically and perhaps come to some general potential differences. What does the warmth of the sun through the day do to the amount of particulates in the atmosphere, for example? My guess is it increases them for a couple reasons. First, because of evaporation of volatiles due to heating, and second, due to rising of existing particles in the atmosphere as they are heated. Perhaps there are other mechanisms too. The greater the amount of particulates in the air, the redder the atmospheric scattering would tend to be (depending on particulate characteristics). You can logically contemplate other effects of the conditions of sunrise vs. sunset as well. Or... just find some real sources, if any studies have been done. I'm curious myself, but thought that the "thinking it through" approach might have benefit too...

- Oshyan

Well reasoned out Oshyan, I'd wondered about that very thing while rendering a recent scene wondering whether the sun was going up or coming down. Thank you.
Title: Re: East and West
Post by: agent unawares on September 11, 2017, 11:22:18 AM
EDIT: Misread question.
Title: Re: East and West
Post by: zaxxon on September 11, 2017, 12:37:25 PM
Interesting topic and one I've asked myself but never dug into the physical explanations. Here's a link that seems to be a good answer:

https://www.livescience.com/34065-sunrise-sunset.html
Title: Re: East and West
Post by: bobbystahr on September 13, 2017, 11:55:51 AM
Quote from: zaxxon on September 11, 2017, 12:37:25 PM
Interesting topic and one I've asked myself but never dug into the physical explanations. Here's a link that seems to be a good answer:

https://www.livescience.com/34065-sunrise-sunset.html

I found this bit quite drole
"According to the astrophysicist Neil Degrasse Tyson, director of the Hayden Planetarium in New York, there's also a trick for distinguishing a sunrise from a sunset played in reverse. Because of Earth's tilt, the sun doesn't rise or set along a vertical line, but at an angle. "When viewed from all latitudes north of the Tropic of Cancer (23.5 degrees north latitude), the sun always rises at an angle up and to the right, and sets and an angle down and to the right," Tyson writes on his website. "That's how you can spot a faked sunrise in a movie: it moves up and to the left. Filmmakers are not typically awake in the morning hours to film an actual sunrise, so they film a sunset instead, and then time-reverse it, thinking nobody will notice."

So if you see a rising sun move up and to the left, you know you're in the twilight zone. Better head back to the hospital."
Title: Re: East and West
Post by: masonspappy on September 14, 2017, 09:01:11 PM
Reminds me of "The Newlywed Game" show on TV many years ago. One of the questions asked of the brides (when their husbands were out of the room) was "Ladies, in your neighborhood - remember just in your neighborhood now, does the sun rise in the north, south , east or west?"  2 of the 4 brides got it wrong, much to their husband's chagrin.
Title: Re: East and West
Post by: fleetwood on September 14, 2017, 10:41:18 PM
One subjective factor.
Sunsets fade to black. Sunrises fade to blue.

Sunset also seem more intense as the eyes adapt to darker and darker skies, allowing you to see both strong and subtle hues , due to fading against an ever more contrasting blacker background.
Sunrises start in darkness and the white sunlight gradually overtakes the colors as they compete with blue sky. 
Title: Re: East and West
Post by: bobbystahr on September 15, 2017, 01:13:37 AM
Quote from: masonspappy on September 14, 2017, 09:01:11 PM
2 of the 4 brides got it wrong, much to their husband's chagrin.



Ha ha ha ha ha
Title: Re: East and West
Post by: Dune on September 15, 2017, 02:05:53 AM
 ;D ;D

Contrary to Oshyan's remarks (which are very valid, I presume), we often get mist/haze at night, especially in fall, so any sunrise would be hazier than the sunset after the haze has been burnt away again.