Earlier quoted context omitted.
This study accounts for missing ordinary matter, not dark matter. The linked article makes this clear in the first paragraph. Sometimes I wonder if the first commenters (and often top commenters) on HN read the article at all or just respond based on the headline, because these comments often seem barely related to the actual article content.
I had read the entire article, and it was not clear.
> Unlike dark matter, ordinary matter emits light of various wavelengths and thus can be seen. But a large chunk of it is diffuse and spread thinly among halos that surround galaxies as well as in the vast spaces between galaxies.
> Due to its diffuse nature, roughly half of ordinary matter in the universe went unaccounted for and had been considered "missing"—until now.
Not being mean, genuine question: How would you improve the clarity of this?