Ah, yes GIMP, I knew distinctively that the explosion is a common common way of manipulation of GIMPs ready to use "effects", and that I've seen many others and which GIMP can be used for. I for one want to use Inkscape not because it is hard to use, because it has SVG. Which is something for high resolution and still is good.
But overall the first one is nice. Just would wish that you could maybe use a bit more creativeness, and imagination, with hard work. It's just that, it seems something that was worked fast. Just my opinion though.
Hmm...I think that all three are great...the reason why the planet isn't spherical in the second one is that the wrong screen dimensions were used...in GIMP, you have to have a perfect square for the polar coordinates to work well.
They all look fantastic though...