Matter known as ordinary, which makes up everything we know, corresponds to only 5% of the Universe. Approximately half of this percentage still eluded detection. Numerical simulations made it possible to predict that the rest of this ordinary matter should be located in the large-scale structures that form the 'cosmic web' at temperatures between 100,000 and 10 million degrees. Scientists observed this phenomenon directly. The research shows that the majority of the missing ordinary matter is found in the form of a very hot gas associated with intergalactic filaments.