Very beautiful sky, I think it would be better if you made the sillohuetes a stronger more integral part of the composition. Or had more detail in the dark area.
very pretty, on my monitor it's a bit dark, I can just barely make out what looks like some cool lines in the sand - my preference would be to see more of the darkness, meets challenge though and great sky - good job :)
I'd like to see more sky and less black hole effect up front. At least on my monitor everything from the horizon line down is solid black. The horizon should be positioned at a 1/3 line with the more interesting or important part of the image getting the most space= the sky in this case.