Exotic atmospheres

General discussion about Celestia that doesn't fit into other forums.
Topic author
chris
Site Admin
Posts: 4211
Joined: 28.01.2002
With us: 22 years 9 months
Location: Seattle, Washington, USA

Exotic atmospheres

Post #1by chris » 23.05.2003, 07:58

Image

More fun with the new atmosphere code . . .

Does anyone know what sort of atmosphere could produce a sunrise like the one above? I guess it would have to absorb both red and blue light more than wavelengths in the middle of the visible spectrum . . .

--Chris

Avatar
t00fri
Developer
Posts: 8772
Joined: 29.03.2002
Age: 22
With us: 22 years 7 months
Location: Hamburg, Germany

Re: Exotic atmospheres

Post #2by t00fri » 23.05.2003, 12:04

chris wrote:Image

More fun with the new atmosphere code . . .

Does anyone know what sort of atmosphere could produce a sunrise like the one above? I guess it would have to absorb both red and blue light more than wavelengths in the middle of the visible spectrum . . .

--Chris


Looks all like great potential!

What about a nice bloodred sunset on earth?;-) In Greece they are said to be particularly beautiful...

In the old code I had checked explicitly for sunsets some time ago, which did not involve any redening of the atmosphere etc.


Bye Fridger

granthutchison
Developer
Posts: 1863
Joined: 21.11.2002
With us: 21 years 11 months

Re: Exotic atmospheres

Post #3by granthutchison » 23.05.2003, 13:41

chris wrote:Does anyone know what sort of atmosphere could produce a sunrise like the one above?
Tricky. Red sunrises are due to scattering rather than absorption, and are therefore largely independent of the molecules making up the atmosphere.

Grant

the guardian
Posts: 18
Joined: 25.04.2003
With us: 21 years 6 months
Location: center of the universe

Post #4by the guardian » 23.05.2003, 15:19

The atmosphere contents like grant stated and the color of the star the planet revolves around. The trick is in figuring out the correct hue based on all those variables.
-the guardian

granthutchison
Developer
Posts: 1863
Joined: 21.11.2002
With us: 21 years 11 months

Post #5by granthutchison » 23.05.2003, 15:46

A hot blue star decreases the amount of red light available, but doesn't altogether eliminate it. The black-body spectrum in the visible band (a rough first approximation to the energy output at various wavelengths) doesn't change in shape very much at all once you get into stars much hotter than the sun. A lot of blue, a moderate amount of green, but still a fair bit of red. At sunset you'd see a very bright blue sky and perhaps a reddish-purple cast to the sun and the sky around it - because the dimmer red light reaching you directly from the sun would have a pretty large blue component scattered into the light path on its way to your eyes.

So green is very tricky, because it is never a dominant wavelength in the black-body spectrum, and it isn't picked out preferentially by scattering.

Grant


Return to “Celestia Users”