The uniform image of the full moon is well known from the beginning of history. In the last decades there are photos with similar configuration of the earth observed from the moon and from space, as well as of all the planets and their moons. The photos are all nearly uniform. Such images are considered non-Lambertian since they do not comply with Lambert Cosine Law of light scattering. Theories of the uniformity deal only with the moon. Apart from being not persuasive for the moon case, they are not applicable to most other cases. There are thousands of thousands of similar photos, but there is not a single true photo that does comply with Lambert cosine Law. Photos that do comply with the law are all "rendered", that is, at least partly simulated. A calculation based on fundamental principles is presented to clarify the uniformity in all cases regardless of the observed object and its surface properties. The uniformity is a direct outcome of a single sunlight scattering by the object surface, and there is no need of further assumptions or models to justify it.

Ref: https://arxiv.org/ftp/arxiv/papers/1808/1808.01024.pdf