We have a fair understanding of the fundamental mechanisms that regulate star formation in galaxies, from the interstellar matter to the diffuse clouds distributed in space whose gravitational contraction leads to the birth of stars within large stellar clusters. But observations of distant galaxies have questioned this picture, the size and mass of these distant stellar nurseries largely exceeding that of their local counterparts. An international team of astrophysicists led by the Universities of Geneva (UNIGE), Switzerland, for the observations and Zurich (UZH) for the simulations has tackled this inconsistency, which seems to question our knowledge of star formation when we study the early universe, far away in time and space. They have found the first answers thanks to new observations of the so-called cosmic snake. Their study is published in the journal Nature Astronomy.