Distances in the universe

Space is expanding. But the expansion rate, dubbed as Hubble constant, is not constant. There appears to be an acceleration. And there are different measurements which do not agree. It is related to a mystery called dark matter and possibly other physics we do not understant yet. We do not know yet much about the universe. It is clear however that measuring distances is one of the central tasks in order to investigate such deep questions. From this article on cosmography which investigates the large scale structure nearby. ``The large scale structure of the universe is a complex web of clusters, filaments, and voids. Its properties are informed by galaxy redshift surveys and measurements of peculiar velocities." The expansion of the universe allows us conveniently to determine how far objects are away. The group led by Helene Courtois also made a nice movie:
The story which these researchers investigate is very much shows how important it is to learn about how to visualize three dimensional space. Also using velocity fields: