Below is an uncomposited version of my Earth render. You can see the light haze around the edges. That's the atmospheric scatter sphere that's a little bigger than the Earth itself. Once the light passes through it, it affects the surface of the Earth resulting in this nice orange color around the edges of the day/night transition. The problem, however, is the white haze around the edges of the planet itself are sharp and in order to affect the surface color, the atmosphere scatter sphere must be on the same layer, therefore, I'm unable to blur it slightly.
This is the atmospheric scatter layer on it's own. I've tried duplicating it, moving the dupe onto a new layer behind the Earth and then blurring that to help hide the sharp edges but it's still not ideal, especially when up close.
My question is, can I still have the atmosphere scatter mesh affect the surface whilst not being a part of the render itself? Can it affect the light off camera, so to speak?
1) Atmosphere Mask (Uses the 2nd layer(Earth) to mask the atmosphere mesh which removes noise) 2) Earth (Includes a Surface mesh, Cloud mesh and Atmosphere Scatter mesh) 3) Atmosphere (A different atmosphere volume that creates a blue outer glow) <-- Irrelevant to problem
This is the best I could do with risingfall's answer. In order to get the light to change the surface I can't fade it as much as I'd like so from a far you can't really see the fade as much but it's miles better than before, I believe.