Lol anyways getting them to spin in place can be a bit tricky because of the fact I don't have multiple pictures of said object. To make the planets spin would require a map of the planet to create each dimension of the animation. I could create them myself but need I remind you that I'm not exactly the artist type. If anything, if I was to remake some of them, they wouldn't look correct. Not mention the fact that some of the planets would even look like they're rotating because of their colors.
The second idea proves to be also difficult considering I'd have to create an entire set. Are you set on the idea of a rotating solar system in a hand or do you just want a signature that looks space-ish? I could come up with some ideas myself if that's ok with you. Of course, I'd have animation in mind because I'm having fun experimenting.