Overindulged and fell asleep: astronomers have discovered the largest black hole in the early universe.

Astronomers using the James Webb Space Telescope have discovered a "sleeping" supermassive black hole that existed just 800 million years after the Big Bang. This cosmic giant "fell asleep" after consuming an excessive amount of galactic gas. It is an unusual black hole, as it has a mass approximately 400 million times that of the Sun, making it the largest black hole observed by the Webb telescope in the early universe. This finding further deepens the mystery of how supermassive black holes became so massive so quickly in the early universe. The study was published in the journal Nature, reports Space.

Unusual Black Hole

When astronomers find supermassive black holes at the centers of galaxies in the local universe, which have existed for billions of years, these cosmic monsters typically possess about 0.1% of the mass of their host galaxies. However, the giant black hole discovered in the early universe has a mass that constitutes about 40% of its host galaxy's mass. This is astonishing.

Astronomers expected a black hole of this size to actively consume matter to grow, but it appears to do so very slowly, if at all.

When black holes feed on matter, an accretion disk forms around them. The gravity of the black hole causes heating and friction of the matter in this disk, resulting in the emission of bright radiation. This is how a black hole can be detected. If, however, the cosmic giant is in "sleep mode," meaning it hardly consumes any matter, it becomes nearly impossible to observe.

But the identified sleeping supermassive black hole is different. Its immense mass grants it significant gravitational influence, allowing it to be seen. Astronomers have determined that the black hole is located at the center of a relatively small galaxy, raising questions about how such a gigantic black hole formed within it.

The Mystery of Black Holes in the Early Universe

Supermassive black holes are found at the centers of all galaxies, with masses millions or billions of times greater than that of the Sun. Unlike stellar-mass black holes, which form from the deaths of massive stars, supermassive black holes are believed to grow through the merging of more massive black holes and the continuous intake of galactic gas.

Astronomers believe that creating a supermassive black hole takes over a billion years. Yet, the Webb telescope has already detected giant black holes that existed just 600 million years after the Big Bang. Astronomers are puzzled by how they appeared so quickly. The enormous size of the discovered black hole and the fact that it is not rapidly growing through matter consumption only intensifies the mystery.

The study's authors suggest that such black holes may have initially formed as very large entities. However, there is a possibility that they experience periods of highly active matter consumption, followed by extended periods of dormancy.

How Did Black Holes Become So Large in the Early Universe?

Scientists, through computer modeling, have determined that such black holes could have exceeded the limit of how much matter they could consume for a relatively short time. This limit is known as the Eddington limit, which indicates that there comes a point when the radiation pressure from their disks repels incoming matter, causing the black hole to stop feeding.

The authors of the study believe that black holes in the early universe may have temporarily surpassed the Eddington limit and, during this time, grew at a very rapid pace. Calculations show that such periods of extremely fast growth last from 5 to 10 million years, after which the black hole "falls asleep" and remains in this state for about 100 million years. This suggests that early massive black holes may be more frequently detected when they are in "sleep mode."