As an artist (when I do get time and inclination to paint - not as much as I should, lately) I have always been partial to skies and atmospheric effects.
No question - the painting of atmosphere is beyond science - it's an art, and it lends greatly to the experience of a painting, or a visual 3D reality in virtual world, like Second Life.
When I paint skies, I notice just how subtle the gradations of atmosphere can be - and now Linden Labs announced that WindLight atmospheric rendering comes to Second Life! (I did not put the exclamation point there, but I can agree with Linden Labs, this is a big deal - at least for me, as an artist, it is).
"…What is WindLight? How did this happen?
WindLight “simulates the ways that sunlight is scattered by the atmosphere under different climatic conditions, such as fog or haze”. Long story short: killer skies and kick ass environments.Linden Lab has teamed up with and acquired Windward Mark, who’s responsible for developing this visual excellency. We warmly welcome our new brethren!
For more details, including the history of Windward Mark and the story behind our acquisition, see our press release and the Boston Globe article, related to Cory Linden’s post about our Boston Recruiting Party."
Here's some examples of what the skies in Second Life are going to start looking like soon:

Look at the sky - it's so well done! it's beautiful - wonderful, really.

The effects here are almost magical.

You can see the whole set here.