*wow* Epic scenery! Your picture is marvelously stunning! The shown destruction tells a breath-taking story of loss and/or defeat, yet the spaceships offer hope - like the people could get away in time ... It's a great composition and I like it very much!
also realism note that would make it better, have the smoke taper off in the atmosphere, so its like a flat dome, the smoke can only rise so far, and it creates a great visual effect if you can pull it off