From William C. Gill Jr.:

Re: Moon like that in “Avatar” could be real, astronomers say (Dec. 20): Mr. Cameron is very careful with his work, and had scientific advisors galore. I wouldn’t at all be surprised if Pandora’s sun was picked specifically because it COULD have such a moon.

People, at least some of them, are walking out of Avatar in a state of depression. Pandora is so beautiful that the reality outside the theater is quite a blow to the believers. You might want to cover that.