The three galaxies (circled in green) that form the EGS77 galaxy group are glowing just 680 million years after the Big Bang. These galaxies have been observed ionizing the atoms around them, generating overlapping bubbles of ionized hydrogen (depicted by an artist in the inset). Astronomers believe that as more galaxies formed over time, such bubbles grew and eventually overlapped throughout the universe, bringing the dark ages to an end.