Observations by the NASA/ESA Hubble Space Telescope have taken advantage of gravitational lensing to reveal the largest sample of the faintest and earliest known galaxies in the Universe. Some of these galaxies formed just 600 million years after the Big Bang and are fainter than any other galaxy yet uncovered by Hubble. The team has determined, for the first time with some confidence, that these small galaxies were vital to creating the Universe that we see today.

Source: Hubble spies Big Bang frontiers | ESA/Hubble