Help!

Inspired by our recent discussion in Science, Jetter just informed me that he would like a "Solar System Birthday Cake". He went on to describe it: "Each planet could be a cake that you could decorate with icing. And you could put little aliens on top of some of them, but not Mercury because they would burn up. The sun would have to be really big, like the size of the table. It will be really great mom!" Uh, yeah, right. I'm sure glad you're not asking for anything too difficult Jetter! Somehow I don't think the oblong cake with "Happy Birthday" written on it is going to suffice.