Well, you can rest easy knowing that there are few people who can replicate the wonders of the cosmos so dynamically as you.
But if you really feel you're lacking so much, I suggest finding other artists here on DA who work with similar subjects and use their tutorials. It's certainly helped me with some of my line drawings.
There's nothing wrong with a little copying of somebody else, so long as you give credit where it's due - it's actually a huge compliment, really.
~~~~ Is it that you lack the patience or the inspiration to work on new things? I'm no realistic painter, but I could offer concept drawings as a base if you ever need it.