Akio K. Inoue

A dense fog, through which only occasional headlight beams pierce. So it was in the early universe: young galaxies were wrapped in clouds of neutral hydrogen, which eagerly absorbed ultraviolet light. But sometimes gaps appeared in this shroud, and ionizing radiation burst out, making the cosmos transparent.

The night sky is full of deceptive lights. Astronomers were searching for galaxies that ignited in the first few hundred million years after the Big Bang: their light has traveled to us for nearly 13 billion years. Six faint smudges were selected from images taken by the Hubble and Spitzer space telescopes.