Study of galaxy more than 12 billion light years away shows black holes may be smaller than believed, challenging models of cosmic growth.
Published On 25 Sep 2025
“Supermassive” black holes may not be as enormous as once assumed, scientists have reported.
Astronomers told the media on Thursday that, following a breakthrough study of a distant quasar, an extremely bright, active core of a very distant galaxy, the supermassive black hole at its heart has a mass that is equal to “only” about one billion suns, making it one-10th of what was assumed.
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A team from the University of Southampton, working with European colleagues, observed the galaxy, more than 12 billion light years away, using state-of-the-art equipment at the European Southern Observatory (ESO) in Chile.
“Despite the quasar’s extreme luminosity, the black hole at its heart was found to have a mass equal to ‘only’ around one billion suns,” Associate Professor Christian Wolf told ANU Reporter.
He added that instead of spinning rapidly as expected, the black hole was “belching up” gas, driven outwards by the blinding intensity of light.
The black hole at the centre of this young galaxy was first detected in 2024 by Wolf and his colleagues at the Australian National University (ANU).
Professor Seb Hoenig of the University of Southampton said the discovery helps solve a longstanding mystery.
“We have been wondering for years how it’s possible we discovered all these fully grown supermassive black holes in very young galaxies shortly after the Big Bang. They shouldn’t have had the time to grow that massive,” he told the Press Association (PA).
The study, published in Astronomy and Astrophysics, used Gravity+, an instrument that combines light from four of the world’s largest telescopes at ESO’s Very Large Telescope in Chile. The team, which also included researchers from France, Germany, Portugal and Belgium, analysed the hot gas spiralling into the black hole.
Their results suggest that intense radiation is blasting most of the gas away, preventing the black hole from gaining mass as quickly as previously thought.
“Think of it like a cosmic hairdryer set to maximum power,” Hoenig explained to PA. “The intense radiation around it is blowing everything away that approaches it.”
The findings may lead scientists to reconsider the methods used to measure black holes and reshape models of cosmic evolution.
