Record-Breaking： Astronomers Find 36-BILLION-Sun Black Hole - The Biggest Ever

Astronomers have uncovered one of the largest black holes ever measured. A cosmic giant weighing billions of suns. Its sheer size challenges everything we thought we knew about black holes. In this video, we'll explore what makes this black hole so extraordinary, and why it may change the way we think about the universe. The Cosmic Horseshoe is a striking galaxy system best known for how it distorts light. Its mass bends the light of a more distant background galaxy into a near-perfect arc, creating what astronomers call an Einstein ring. This rare phenomenon turns the galaxy into a natural magnifying glass, and makes it especially valuable for study. A team led by scientists from the University of Portsmouth in the UK and the Universidade Federal do Rio Grande do Sul in Brazil began examining this system to study its dark matter halo. But as they analyzed the data, they found something even more remarkable. Signs of an ultramassive black hole at its center. To measure it, they combined two approaches. First, using the Multi-Unit Spectroscopic Explorer, MUSE, instrument on the Very Large Telescope, they studied the motion of stars. Near the galaxy's center, stars were moving at nearly 400 kilometers per second, indicating the presence of a powerful gravitational source. Second, they modeled the gravitational lensing effect seen in Hubble Space Telescope images. The way the galaxy bent light from the background source revealed details about how mass is distributed within it. By combining stellar dynamics with lensing, the researchers could separate out how much of the galaxy's inner mass comes from stars, dark matter, and the central black hole. The result? A black hole weighing in at about 36 billion solar masses. This figure makes the cosmic horseshoe black hole one of the largest reliably measured to date. Other candidates, like TON 618, have been suggested to be even bigger, possibly exceeding 60 billion solar masses. But those estimates rely on less direct methods with much larger uncertainties. Its result stands apart for its robustness. By testing their models against multiple scenarios and applying Bayesian comparisons, the team confirmed the outcome across different approaches. At 5 billion light-years away, this galaxy revealed one of the most distant confirmed black holes, an unexpected find from a dark matter study. The discovery of the cosmic horseshoe black hole is significant not only because of its size, but also because of what it tells us about the relationship between galaxies and their central black holes. Astronomers have long known about a correlation between a galaxy's mass and the velocity dispersion of stars in its central regions. This is known as the m-sigma relation. It suggests these galaxies evolved together, likely through processes where the energy from accretion and jets influences star formation. The cosmic horseshoe it, however, lies well above this expected relation. Its enormous mass does not match the typical stellar speeds in its host galaxy. This implies that at the very highest masses, these and galaxies may not grow in lockstep. Instead, ultramassive black holes could follow a different growth path than the ones in smaller galaxies. One explanation is galaxy mergers. Over cosmic history, galaxies frequently collide and merge. When this happens, their central black them also merge, creating progressively larger ones. Repeated mergers, combined with long periods of accreting gas, could explain how some of these reach the tens of billions of solar masses. It may be a direct outcome of such a history. This measurement also feeds into the debate about whether these have an upper mass limit. Theoretical models suggest that beyond around 50 to 100 billion solar masses, these can no longer feed efficiently. Gas either falls in too quickly to add more mass, or gets expelled by radiation and winds. With 36 billion suns, it sits close to this theoretical ceiling, making it a natural test case for these ideas. By combining stellar motion with gravitational lensing, astronomers can now measure them billions of light years away, mapping their growth across cosmic history. The existence of this large carries several implications for astronomy. First, it challenges our assumptions about IT galaxy coevolution. If ultramassive black holes can outgrow the expectations set by stellar velocity dispersion, then feedback processes like jets and winds may operate differently at these scales. This could help explain why the most massive galaxies in the universe are often quiescent, with little or no star formation left. Second, it points to the role of cosmic mergers. Our own galaxy is on track to merge with the Andromeda galaxy in about 4.5 billion years. When that happens, their central black holes, currently a few million suns in the Milky Way and over 100 million in Andromeda, will eventually merge into a far larger one. It offers a glimpse of what repeated mergers over billions of years can produce. Third, the discovery sets the stage for future surveys. The European Space Agency's Euclid mission, launched in 2023, is now mapping billions of galaxies, and is expected to uncover thousands of new gravitational lenses. Systems like it could soon be studied in much greater numbers, allowing astronomers to identify a broader population of ultramassive them and determine whether the horseshoe is exceptional or part of a larger trend. This also connects to the field of gravitational wave astronomy. When two supermassive holes merge, they release low-frequency gravitational waves. Instruments such as pulsar timing arrays have already begun detecting the background hum of these cosmic events. These, like the one in the cosmic horseshoe, represent the types of objects likely contributing to this signal. Finally, could even larger ones be hiding? With upcoming telescopes like ELT and LISA, astronomers are ready to test nature's ultimate limits. The 36-billion-solar-mass black hole in the cosmic horseshoe marks a new milestone, challenging how we think these giants grow. With telescopes like Euclid, more discoveries are coming. And each one will reshape our view of the universe. Stay tuned, because the cosmos always has another surprise. Transcribed by ESO. Translated by — Transcribed by — ESOcast is produced by ESO, the European Southern Observatory.