The exact timings of the first stars, galaxies, supermassive black holes, and quasars, and the start and end timings and progression of the period known as reionization, are still being actively researched, with new findings published periodically. As of 2019 : the earliest confirmed galaxies (for example GN-z11) date from around 380–400 million years, suggesting surprisingly fast gas cloud condensation and stellar birth rates; and observations of the Lyman-alpha forest, and of other changes to the light from ancient objects, allow the timing for reionization and its eventual end to be narrowed down. But these are all still areas of active research.