Oldest black hole in the Universe discovered – 01/17/2024 – Science

An international team of astronomers discovered a black hole that existed when the Universe was just 400 million years old, according to a study presented this Wednesday (17).

The discovery takes what was known until now “about 200 million years” back, Jan Scholtz, an astrophysicist at the Kavli Institute of Cosmology at the University of Cambridge, in the United Kingdom, told AFP.

The existence of a black hole in the Universe’s youth, more than 13 billion years ago, “will fuel a new generation of theoretical models”, added the expert, co-author of the study published in the journal Nature.

A black hole like this must be imagined as an object with a mass estimated at 1.6 million times that of the Sun. It is invisible, like all black holes, and absorbs the surrounding matter, emitting a gigantic amount of light in its surroundings.

It was this light that facilitated the location of the galaxy GN-z11 — where the black hole is located —, discovered in 2016 with the help of the Hubble Space Telescope.

The galaxy GN-z11 was then the oldest and therefore the most distant observed by Hubble. In 2022, the James Webb Space Telescope made it possible to detect the black hole located there.

This discovery adds to others that were made possible thanks to the James Webb telescope and reveals the existence of a young Universe that houses objects much more luminous than previously thought.

The black hole detected by the international team led by the University of Cambridge dates back to 430 million years after the Big Bang. This is the time of cosmic dawn, when, upon leaving the so-called “dark” ages, the first stars and galaxies appeared.

Various hypotheses

One of the unknowns of a black hole this size is understanding how it could grow so quickly.

Its characteristics “suggest a faster and earlier growth than that of other black holes known at very ancient times,” Stéphane Charlot, an astrophysicist at the Paris Institute of Astrophysics and co-author of the study, told AFP.

This means that “the mechanisms of black hole formation in the young Universe could be different from those we know in the nearest Universe”, he added.

The most common hypotheses so far consider that the Universe was too young at that time to harbor such a massive black hole, points out Professor Roberto Maiolino, an astrophysicist at Cambridge and co-author of the study, cited in a statement.

Therefore, “we must consider other models to explain its emergence”, he adds.

Theorists anticipate the idea that it was born “big”, from the explosion of a dying supermassive star or the rapid concentration of a dense gas cloud, without going through the star formation phase.

Once born, the black hole in the GN-z11 galaxy would have filled with the gas that surrounded it to grow quickly and easily because “observations seem to indicate a strong density of this gas”, according to Charlot.

The study published in Nature “does not rule out any of these hypotheses”, according to Stan Scholtz, who hopes that the exceptional observation capabilities of the James Webb telescope will provide more information.

“We can expect the detection of other black holes when we accumulate more deep observations of wider portions of the sky,” the astrophysicist pointed out.