One sphere is glossy blue, while the other is slightly larger with an image that goes into transparency, so only the landmass is shown, and casts a shadow on the blue sphere.
I've set up the scene with an HDR and a couple of area lights so it looks better.
The render looks fine when I see the progress, but when I play it back, I notice there's some TINY flickering going on, as if there's something obstructing the area lights. 10 frames can be good, then theres every other frame of flickering for 30-40 frames, and then a couple of good frames again, and.. so on..
I've tried adjusting diffuse and glossy depth. I switched off the area lights, and the flickering disappeared, but now the render doesn't look as good.

Edit:
I increased sampling on the aera lights (default is 1, I increased to 3), don't know how far it's necessary to increase, but it did not have any effect.
Any suggestions on what I may try?