Ancient Quasars Challenge Early Universe Black‑Hole Growth Models

Using the European Space Agency’s Euclid space telescope, astronomers have identified 31 quasars that formed less than 670 million years after the Big Bang. Among them are the two earliest known quasars, dating to about 13.1 billion years ago, when the universe was roughly 5 % of its current age. The objects shine a trillion times brighter than the Sun and are powered by supermassive black holes hundreds of millions to billions of solar masses.

The study, led by doctoral researcher Daming Yang of Leiden University and co‑authored by Joseph Hennawi of the University of California, Santa Barbara, places the quasars in the epoch of reionization – the cosmic dawn when the first stars and galaxies ionised the intergalactic hydrogen fog. "The most important thing these distant quasars tell us is that these supermassive black holes were already present in the extremely early cosmic times," Hennawi said, calling it "a major unsolved problem in astrophysics." The findings push current theories of black‑hole formation and growth to their limits, suggesting that early black holes either formed already massive or grew far faster than previously thought.