A team of astronomers has proposed an explanation for the objects known as "little red dots", tiny red points recently observed by the James Webb Space Telescope. According to their hypothesis, these would be black holes that grew extremely quickly during an early stage of their evolution, accounting for their observed properties without invoking more exotic scenarios.

The "little red dots" emerged in the first JWST data as compact, very red sources surprisingly abundant in the early universe. Their nature has been debated ever since: it was unclear whether they corresponded to young, dense galaxies, to interstellar dust reddening the light of normal stellar populations, or to active nuclei powered by black holes. The new proposal favours the latter option, with the particularity that these black holes would have undergone a highly efficient accretion phase in their earliest moments.

The idea fits with an open question in astrophysics: how supermassive black holes could have formed so soon after the Big Bang, as some observations suggest. If the "little red dots" represent a stage of accelerated growth, they could be intermediate links in the formation of the black holes that today reside at the centres of massive galaxies.

The hypothesis, still preliminary, will have to be tested against additional observations confirming the presence of active accretion in these objects and ruling out alternative explanations. Upcoming data from JWST and other observatories should allow their masses, accretion rates and ages to be measured more precisely, and thus determine whether the "little red dots" are indeed black holes in the midst of a growth phase.