So after getting much helpful critique and looking over the image some more I went about reworking it, this was the outcome, I saw the new star trek movie and that actually helped a lot with revising the lighting a bit and adding more distinct lens flares haha.
So basically its a big alien ship firing onto a planet and making a huge shock wave that disintegrates most things in its path like poor hospital ships evacuating the planet bellow, it also erases the planets surface turning it into a desolate ball of rock. The idea is that the aliens go around and "save" planets from the civilisations living on them, they decide if the race is exploiting its resources and harming the planet by doing so then if they are they wipe the slate clean and let the planet start a new. Kind of a more violent version of The Day The Earth Stood Still.
Enjoy