File:solar system compression artifacts.png

The Voyager spacecraft has reached the outer boundaries of the Solar System which is nominally divided into sections such as the 'heliosphere', although there are no actual definitive demarcations and there are both arbitrary thresholds and transient fluctuations. If this were a typical real digital image with insufficient depth of subtlety, brightness gradation would show up as bands of intensity joined by digital compression effects, in a 'darker to lighter' progression just like in this graphic. The joke here is that those artefact gradations actually exist in space!