Dwarf galaxies like lighthouses in the fog of the primordial universe. Small but powerful, dwarf galaxies would have been the 'lighthouses' that cleared the hydrogen fog.
600-800 million years after the Big Bang, starting the so-called re-ionization era in which light started to spread. This is suggested by data from the James Webb space telescope, published in Nature by an international research group led by Hakim Atek of the Institute of Astrophysics in Paris.