Artists use a combination of abstract shapes and precisely shaded geometry to accurately represent those images of space captured by the Hubbel telescope and the like.
The abstract shapes become even more important when an artist tries to faithfully represent astronomical phenomena such as the swirly burly supernovas that mark the passing of a giant star.
Creating that supernova look without using CGI can be a bit tricky, but self-taught filmmaker Thomas Vanz discovered all he needed to copy those cool cosmic events was ink and an aquarium full of water.
Thomas also produced the soundtrack for NOVAE, using natural sounds to further avoid having any digitally produced elements in the film. So when Thomas says he made "space" in his home he really means it!