Celestia Forums

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

chris wrote:

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

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

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