Dear Lord... that is simply stunning. I am seriously stunned by the amount of detail that you've incorporated into this piece and of couse, the simple size and grandeur of it all. In all honesty, if someone showed me this in my astronomy class, I would be compelled to believe that that really existed, somewhere, out there in the cosmos. Also, as a small side note, the border is quite fitting, it's small enough and yet, still is apparent enough to be effective but not imposing.
Damn fine work.
You can easily fake some pictures for NASA's PR department, hehe