Earth surface, night lights and clouds

Attribution: Solar System Scope, "Solar Textures"
Source: https://www.solarsystemscope.com/textures/
License: Creative Commons Attribution 4.0 International (CC BY 4.0)
https://creativecommons.org/licenses/by/4.0/

Earth day and night maps are copies of the existing project's licensed
2048 x 1024 geographic textures. The cloud map was downloaded from:
https://www.solarsystemscope.com/textures/download/2k_earth_clouds.jpg

Cloud map modification: converted to grayscale, stripped metadata and
JPEG-compressed for use as the alpha channel of a real spherical cloud layer.

These maps are material textures, not flat scene backgrounds.