According to data from the Hubble and James Webb Space Telescopes, the origins of the free-flying photons in the early cosmic dawn were small dwarf galaxies that flared to life, clearing the fog of murky hydrogen that filled intergalactic space…“They produce ionizing photons that transform neutral hydrogen into ionized plasma during cosmic reionization. It highlights the importance of understanding low-mass galaxies in shaping the Universe’s history.”…Scientists thought that the sources responsible for most of the clearing must have been powerful – huge black holes whose accretion produces blazing light, for example, and large galaxies in the throes of star formation (baby stars produce a lot of UV light)…Surprisingly, [JWST]'s observations now suggest that dwarf galaxies are the key player in reionization…““Despite their tiny size, these low-mass galaxies are prolific producers of energetic radiation, and their abundance during this period is so substantial that their collective influence can transform the entire state of the Universe.””
Am I understanding correctly that the first light came before the first star?
Yes, photons were released when the universe began to cool enough for electrons to combine with protons to make the first neutral hydrogen atoms. Those first photons are now observed as the Cosmic Microwave Background.
This article presents evidence that the cause of those primordial neutral hydrogen atoms having their electrons stripped away again was not primarily huge celestial formations like supermassive black holes or giant galaxies. Instead, it looks like the early universe produced such a large number of small galaxies that the light from stars in those small galaxies did the deed.
Than you so much for the ELI5!