A quasar from the universe’s first 850 million years has started to look less like a distant pinprick and more like a real physical system. By catching it flickering over time, astronomers have traced the structure of matter swirling around one of the earliest known supermassive black holes. What they found deepens one of cosmology’s biggest puzzles. The object, known as J0439+1634, sits at a redshift of 6.51. This means its light comes from a time just 850 million years after the Big Bang. Quasars are among the brightest objects in the universe, powered by supermassive black holes pulling in gas and dust. As that material spirals inward, it heats up and radiates enormous amounts of energy. Sometimes, it outshines the galaxy around it. Many quasars have already been found from this early era, often called the cosmic dawn. What makes this one stand out is not just its age, but its variability. Astronomers at MIT and elsewhere have detected a quasar flickering from the very early universe. This artist’s concept illustrates a quasar accretion …