In our eagerness to identity the Universe’s occult phenomena of dark energy and dark matter, we often forget that most of its better defined particles also seem to be MIA. Relax.
Two separate teams of astronomers used similar approaches to establish the presence of what is described as baryonic matter in the space between galaxies. It’s thought to only make up about 4.6 percent of everything, with dark matter and dark energy comprising the rest. A fraction of this missing matter could exist as diffuse halos of dust and gas surrounding galaxies like ours, but this still leaves a lot of baryons unaccounted for.
Discoveries in recent years that have established vast webs of dark matter stretching across space have made it increasingly likely that the normally visible matter has accumulated in filaments bridging galaxies.
Expanded out over the cosmic web, the results go a long way in accounting for that missing matter.
Bigger surveys in the future will no doubt provide more data that can help define a more precise figure for the amount of visible matter collecting along the Universe’s dark threads.