Attached Link: http://www.renderosity.com/viewed.ez?galleryid=10700&Start=1&Artist=archetype&ByArtist=Yes

Also set your haze settings fairly high and move the planet away from the camera a bunch (you will then need to resize it larger so it appears the same size in your pic.) The further back you go, the more haze will obscure it. Check out the link to the pic I made to get an idea of what Im talking about (you may not want the haze&fog to be as thick as in mine, but you get the idea.)