That is really well done. I know how difficult it is to create an explosion or shockwave, so 44 layers... that's interesting. I rarely finish with only 44 layers. Certainly speeds up working, because Photoshop won't use up that much memory.

Love the overall detail, but might I make a suggestion? Take out the asteroid(?) that appears to be racing towards the explosion; I assume it's suppose to be a collision? If so, it's not needed. I think it would be way more dramatic without and leaving the reason of the explosion to the imagination. Maybe just hadd a couple of larger planet fragments underneath the explosion layer(s). But... as I said; just a suggestion.

Great work nonetheless!