Blender 2.79 Cycles 1500 Samples + Denoise
Atmosphere and clouds are volumetric.
Textures kindly provided by NASA.
Wow, looks just like a NASA photo.
Thank you! It took a long time, a lot of material work, and research to complete and I’m still not satisfied. Maybe one day I’ll come back to it. I tried many things even displacement for real oceans and rivers but my computer couldn’t handle it. But all in a good days work of trial, error, and learning the limitations of your workstation. 
nice work, it looks too bright, not sure if this is natural or not
but it is awesome
Looks quite good.
though it does look flat. even if sun would be face on, then the water would reflect some light. And clouds shoudl cast shadow onto the ground. hard to identify if in your images that is the case.
I’m with you on that I want to do some long shadow renders. The water is reflecting but its almost a direct reflection you can see it near the center of earth a purplish white look. The waves act like roughness and reflect a lot of the incoming light away at that distance so not a lot gets back to the eye and its dull. But if it was at a grazing angle it would be much brighter. I also used a blackbody node for the color of the sun so it should be the proper color (hopefully).
You are right about the clouds currently they give off more light than they receive so they are acting a little bit like an emission shader because of how high I put the scattering on them. NASA says about 29% of incoming light is reflected back by clouds, but I have no clue what 1 unit of scattering density in blenders volumetric relates to (particularly in size such as parts per km) so I was having difficulty making the clouds look as white as they should be. It always looked too dull so that’s something that still needs work.
Some other difficulties I’m having with it is the atmosphere. As soon as I put a spherical gradient texture on it, it loses all Rayleigh scattering color properties from the volumetric scatter shader. But if I don’t add the gradient texture it will have a very sharp edge no soft fall off. I have no clue why this happens and have not been able to figure it out yet.
Thank you for the critique its very helpful.
I’m not sure either 
I’ve only been able to go off photos but I know those are either under or overexposed. I think the only way to know for sure is either go to space and see it for yourself or have an astronaut critique it, but both seem a little difficult to achieve.
I actually made this because I couldn’t take photos of earth from space.
