An international team of scientists, led by the University of Cambridge, have unlocked a cosmic mystery with the help of the NASA/ESA/CSA James Webb Space Telescope (JWST). The remarkable discovery of an incredibly ancient black hole, dating back to just 400 million years post the big bang, is shaking the foundations of our understanding of the universe. The details of this groundbreaking research, described as "a giant leap forward" by lead author Professor Roberto Maiolino, are published in the respected journal, Nature.
Image Credit: NASA, ESA, P. Oesch (Yale University), G. Brammer (STScI), P. van Dokkum (Yale University), and G. Illingworth (University of California, Santa Cruz)
The Black Hole That Defies Expectations
This black hole, astonishingly massive – with a few million times the mass of our Sun – poses a significant challenge to our existing theories about black hole formation and growth. It's existence at such an early stage in the universe forces us to reconsider our understanding of these celestial phenomena.
Standard models propose that supermassive black holes, like the ones at the center of galaxies such as the Milky Way, evolved to their current size over billions of years. However, the sheer size of this newly discovered black hole suggests alternative formation theories. These might include the possibilities that black holes could either be 'born big' or consume matter at an astonishing rate – up to five times faster than previously considered possible.
The Mysteries of Black Hole Formation
According to prevailing models, supermassive black holes are the remnants of deceased stars that collapse and may birth a black hole approximately a hundred times the mass of the Sun. If this newly detected black hole followed the expected growth trajectory, it would need about a billion years to reach its observed size. Intriguingly, the universe was not even a billion years old when this black hole came into existence.
"It’s very early in the universe to see a black hole this massive, so we’ve got to consider other ways they might form," Maiolino posits. Early galaxies, abundant in gas, would have served as a veritable buffet for burgeoning black holes.
A Voracious Young Black Hole
This ancient black hole, like all of its kind, feeds on material from its host galaxy to fuel its growth. Yet, this black hole, young by cosmic standards, devours matter with a fervor unmatched by its counterparts in later epochs.
The black hole resides within the young host galaxy, GN-z11, illuminating it with an energetic glow from its core. Observing black holes directly is impossible due to their nature; however, their presence can be detected by the characteristic radiance of a swirling accretion disc, which forms near the black hole's edges. The gases in the accretion disc superheat and begin to emit energy in the ultraviolet range, creating a distinctive glow that allows astronomers to detect these celestial bodies.
The Impact on Galaxy GN-z11
Though GN-z11 is a compact galaxy, approximately a hundred times smaller than the Milky Way, the black hole within it could be stunting its development. As black holes consume excessive amounts of gas, they generate an ultra-fast 'wind' that pushes the gas away. This 'wind' could halt the process of star formation, gradually killing the galaxy. Simultaneously, it would cut off the black hole's source of 'food,' leading to its eventual demise.
The Future of Black Hole Research
The sensitivity of JWST opens an exciting new chapter in the exploration of black holes, according to Maiolino, making it the most exhilarating time in his career. He likens the leap in sensitivity, particularly in the infrared range, to upgrading from Galileo's telescope to a modern one overnight.
"Before Webb came online, I thought maybe the universe isn’t so interesting when you go beyond what we could see with the Hubble Space Telescope. But that hasn’t been the case at all: the universe has been quite generous in what it’s showing us, and this is just the beginning" Maiolino said.
He anticipates that even older black holes may be unveiled in the coming months and years. Maiolino and his team aim to use future observations from JWST to identify smaller 'seeds' of black holes, which could help unravel the various ways black holes might form: whether they originate large, or they grow at rapid rates.
The discovery of this ancient black hole is just the tip of the cosmic iceberg. The revelations it brings to light can revolutionize our understanding of the universe and the enigmatic black holes. As we continue to unlock the mysteries of the cosmos, stay tuned with FreeAstroScience for the latest updates, brought to you by your guide to the stars, Gerd Dani.
Reference:
Roberto Maiolino et al. ‘A small and vigorous black hole in the early Universe.’ Nature (2024). DOI: 10.1038/s41586-024-07052-5
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