The Sun and the Moon a Riddle in the Sky

TL;DR

This paper presents a fundamental calculation explaining the uniform appearance of celestial bodies in images, attributing it to single sunlight scattering, challenging previous theories and emphasizing the non-Lambertian nature of such images.

Contribution

It introduces a universal calculation based on fundamental principles that explains the uniformity of celestial images without relying on complex models or assumptions.

Findings

Uniform images result from single sunlight scattering.

Photos that follow Lambert law are artificially rendered.

The calculation applies universally to celestial observations.

Abstract

The uniform image of the full moon is well known from the beginning of history. In the last decades, there are photos with a 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 from the observed object, and there is no need of further assumptions or models to justify it.