“A new project that recycled Hubble Space Telescope images has mapped the invisible dark matter with unprecedented detail. Researchers focused on two galaxy clusters that are so far away, and their light has taken so long to get here, that they are seen as they existed when the universe was about half its present age.
The observations provide additional evidence supporting a leading theory that galaxies form in cosmic webs, with regular material and dark matter condensing into nodes something like water drops gather at intersections of spider silk.
You can also think of it as froth gathering on the tops of ocean waves, said study team member Myungkook James Jee at Johns Hopkins University.”
Any one who looks at a plot of the distribution of the galaxies in the Universe immediately notices that they seem to trace out a lattice structure with giant regions containing no galaxies surrounded by thin walls of galaxies. This result would seem to help explain why this is happening. It still doesn’t explain what dark matter is ultimately, but as the article points out, it’s a strong hint.
This is especially interesting because it would seem to contradict the argument that Dark Matter doesn’t really exist – but has only been invented to explain behavior that could be explained more simply by General Relativity.