Nearby galaxies put a lens on hundreds of distant ones

A cosmic magnifying glass has revealed a cache of 227 faint galaxies that existed as far back as roughly 650 million years after the Big Bang. These are among the faintest galaxies known and might have played a crucial role in the reionization of the universe, when electrons were stripped from hydrogen atoms throughout the cosmos.

The distant galaxies were seen by pointing the Hubble Space Telescope at three closer galaxy clusters, researchers report in a paper to be published in the Astrophysical Journal. The immense gravity of each cluster bends light from galaxies farther beyond and acts like a giant lens, brightening and magnifying galaxies that would otherwise remain hidden, an effect of Einstein’s general theory of relativity.