Just 1.4 billion years after the Big Bang, MXDFz4.4 — a galaxy 100 times smaller than the Milky Way — was blasting ionizing light through the neutral hydrogen that once shrouded everything, giving astronomers their closest-ever look at cosmic reionization in action. This illustration portrays galaxy MXDFz4.4 when it existed 1.4 billion years after the Big Bang. Image credit: NASA / ESA / Leah Hustak, STScI. MXDFz4.4 existed at the end...
