Seeing Deep

By the time the universe was a billion years old, something had given it a real charge. That “something” could be the first galaxies. And thanks to some help from cosmic magnifying glasses, astronomers have seen enough early galaxies to make that possibility more likely.
A few hundred thousand years after the Big Bang, electrons and protons began sticking together to make atoms of hydrogen. The atoms had no electric charge. By a billion years later, though, most of the hydrogen atoms had been split apart, giving them a charge. Learning what caused this can help astronomers better understand the early universe.
In a project known as the Hubble Frontier Fields, Hubble Space Telescope stared at several galaxy clusters for weeks at a time. The gravity of the immense mass in such a cluster acts as a magnifying lens, so it makes the galaxies that appear beyond the cluster look brighter. That revealed galaxies that were just one percent as bright as the galaxies that Hubble could see without