X-ray observations from clusters showed that only 10-20% of the matter could be normal matter, The large-scale structure of the Universe (correlations between galaxies on hundreds-of … The gravity from the dark matter pulled ordinary matter to it. of dark matter in the Universe and to the cluster baryon content. Not ‘dark matter’ — the mysterious, invisible stuff that makes up the majority of the Universe’s contents. strands forming an invisible skeleton, as shown in the central figure (indicated by “Structure formation”).
X-ray observations from satellites have enabled a better understanding of the physics occuring inside clusters, their matter content as well as a detailed description of their structure.
Then galaxies grew at the intersections of these filaments. A large fraction of the mass of our Universe is made out of an exotic, non-baryonic component that is fundamentally different from the ordinary matter that forms visible objects such as stars, planets, galaxies and galaxy clusters. If dark matter were just invisible ordinary matter, we also expect more helium, lithium, etc in the universe than we observe. Gravitational microlensing constrains the amount of MACHOs (massive compact halo objects, such as black holes and invisible planets) we can have in a large mass range, covering most of the plausible candidates. Astronomers have detected much of the Universe’s ordinary matter, which had long been missing from accounts of its total mass. Dark Energy and the Accelerating Universe Invisible Skeleton of our Universe 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6