The patchy progress of cosmic hydrogen reionization. This visualization shows the fraction of ionized hydrogen (HII), across a large region of space, several hundred mega-parcsecs across. It shows the results from the Lumina simulation, at redshift z=7, when the Universe was approximately 800 million years old. Bright regions trace ionized bubbles around galaxies, while dark regions are still neutral at this time.
Methods: AREPO code


