For decades, astronomers have been trying to see as far as they can into the deep Universe. By observing the cosmos as it was shortly after the Big Bang, astrophysicists and cosmologists hope to learn all they can about the early formation of the Universe and its subsequent evolution. Thanks to instruments like the Hubble Space Telescope, astronomers have been able to see parts of the Universe that were previously inaccessible.
NASA's Spitzer Space Telescope has revealed that some of the universe's earliest galaxies were brighter than expected. The excess light is a byproduct of the galaxies releasing incredibly high amounts of ionizing radiation. The finding offers clues to the cause of the Epoch of Reionization, a major cosmic event that transformed the universe from being mostly opaque to the brilliant starscape seen today.