Astrophys. J. 819, 129 (2016)

After 26 years in the business, the Hubble Space Telescope has surprised astronomers once again. This time, Pascal Oesch and collaborators managed to observe a bright galaxy (GN-z11) in its infancy, some 13.4 billion years ago — or 400 million years after the Big Bang. In other words, this galaxy represents the farthest one that we know. In stellar evolutionary terms, GN-z11 formed 200–300 million years after the first stars appeared.

Combining the Hubble images with those taken by the Spitzer Space Telescope, an infrared observatory, reveals that the old galaxy is 25 times smaller than the Milky Way but is forming stars at 20 times the rate of our galaxy. The high rate of activity provides clues to the formation of the early Universe. However, this distance is the limit of Hubble's range. We must rely on future observations by the James Webb Space Telescope (set to launch in 2018) or the Wide-Field Infrared Survey Telescope (mid-2020s) to learn more about the birth of the earliest stars.