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Newly discovered: the most ancient black hole ever observed, existing since the beginning of the universe.

Scientists have identified the most ancient black hole ever seen, with an estimated age of over 13 billion years since the beginning of the universe.

The observations, by the James Webb space telescope (JWST), reveal it to be at the heart of a galaxy 440m years after the big bang. At around a million times the mass of the sun, it is surprisingly big for a baby black hole, raising the question of how it grew so big so quickly.

Prof Roberto Maiolino, an astrophysicist at the University of Cambridge, who led the observations, said: “The surprise is in it being so very massive. That was the most unexpected thing.”

The findings, released on the online platform Arxiv, do not capture a visual image due to its invisible nature as it absorbs all light. However, scientists were able to identify distinct characteristics of its accretion disk, the swirling mass of gas and dust surrounding the massive black hole.

Scientists think that the initial black holes in the universe may hold the key to understanding how the massive black holes found in the centers of galaxies, like our own Milky Way, grew to be billions of times the size of the sun. Previously, it was believed that these black holes grew over time through mergers and consuming stars and other objects. However, this theory does not fully explain the immense size of modern supermassive black holes.

New data on the galaxy known as GN-z11 reveals that the enigma of its origins can be traced back to the early stages of black holes, indicating that they may have been either large from birth or experienced rapid growth.

A Hubble space telescope image of galaxy GN-z11 (shown in the inset) as it was 13.4bn years in the past, 400m years after the big bang

Prof Andrew Pontzen, a cosmologist at University College London who was not involved in the research, stated that comprehending the origins of black holes has always been a mystery. However, recent findings utilizing the capabilities of JWST to look back in time have revealed that some black holes grew at an unexpected rate in the early universe. This new information deepens the existing puzzle.

One explanation, known as the heavy seeds scenario, is that an early generation of black holes was born from the direct collapse of vast clouds of gas, rather than from burnt-out stars that collapsed under their own gravity at the end of their life. Another possibility is that compact clusters of stars and black holes merged very rapidly in the early universe.

One possible explanation, although less certain, is the presence of primordial black holes that were formed during the cosmic inflation phase, when the universe expanded faster than the speed of light shortly after the big bang.

This would reverse the expected sequence of events, where galaxies are thought to have formed first and then black holes begin to grow within them. Primordial black holes would be integrated into the structure of the universe from the beginning.

“If that were true, it would have deep implications for the opening fraction of a second of our universe,” said Pontzen. “Either way, the story of how black holes and galaxies grew up together is a riveting one that we are only just starting to piece together.”

NASA’s space observatory has made a series of impressive discoveries just two years after its launch. JWST is significantly more sensitive than other telescopes, like Hubble, in detecting infrared light, which allows us to see the most distant objects. According to Maiolino, it’s like upgrading Galileo’s telescope to a modern one, condensing 400 years of discoveries into the timeframe of JWST operations.

Maiolino stated that there was a chance for the telescope to reveal a mundane continuation of our current understanding, but this is not the case. The universe has been surprisingly abundant in its discoveries, bringing forth unexpected findings.

Can you explain what a black hole is?

Black holes are among the universe’s weirdest and most ominous objects. They have such intense gravity that neither matter nor light can escape their grip. A black hole’s threshold is traced out by its event horizon, the point of no return. Anything that strays across this boundary is gone for good.

This artist’s concept shows a galaxy with a brilliant quasar, a very bright, distant and active supermassive black hole that is millions to billions of times the mass of the Sun, at its centre.

Studying them is difficult as they cannot be directly observed, but using the principles of physics can provide unusual revelations. As one approaches a black hole, the strength of gravity becomes so intense that objects would be elongated in a phenomenon called spaghettification. At the event horizon, gravity is so powerful that light is bent into a complete loop around the black hole, allowing for the possibility of seeing the back of one’s own head while standing there.

What lies beyond the event horizon is unknown. Einstein’s theory of general relativity suggests that at the centre of a black hole density would become infinite, creating a gravitational singularity. This rupture in space-time would have no “where” or “when” and would sit beyond the realm of the conventional laws of physics. But it is not clear whether such singularities actually exist.

There are various sizes of black holes. When formed from the remains of large stars, stellar black holes can weigh up to 20 times more than our sun. Supermassive black holes, such as Sagittarius A* located at the center of the Milky Way, can have a mass equal to millions or billions of suns and have a significant impact on the evolution of galaxies.

In the last ten years, astronomers have made important progress in studying black holes. They captured the first image of a black hole’s halo using the Event Horizon telescope in 2019 and have also observed cataclysmic mergers of black holes by detecting gravitational waves that travel through space-time. By studying even more distant objects with the James Webb telescope, scientists hope to uncover the mysteries surrounding the origins of these intriguing entities.

Source: theguardian.com