Help! Can't get composition to display in render.

Support Lighting and Rendering
1

I made an earth, and had a glowing atmosphere in composition but it won’t show up when I render, any ideas? http://bafull.cgcookie.netdna-cdn.com/images/smilies/sago/confused.gif

2

us side of earth2.png960×540 114 KB

Here’s what it looks like rendered without the composition, it’s supposed to have sharper featues and a glowing atmosphere.