NASA has released these beautiful images of the 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 the Hubble Space Telescope. 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.
An international team of astronomers, led by Hakim Atek of the Ecole Polytechnique Fédérale de Lausanne, Switzerland, has discovered over 250 tiny galaxies that existed only 600-900 million years after the Big Bang – one of the largest samples of dwarf galaxies yet to be discovered at these epochs. The light from these galaxies took over 12 billion years to reach the telescope, allowing the astronomers to look back in time when the universe was still very young.
To make these discoveries, the team utilized the deepest images of gravitational lensing made so far in three galaxy clusters, which were taken as part of the Hubble Frontier Fields program. These clusters generate immense gravitational fields capable of magnifying the light from the faint galaxies that lie far behind the clusters themselves. This makes it possible to search for, and study, the first generation of galaxies in the Universe.
More galaxies, at even earlier times, are likely to be revealed when Hubble peers at three more of these galaxy clusters in the near future.