Evrim Yazgin
Cosmos science journalist
The James Webb Space Telescope (JWST) has revealed the oldest black hole ever observed. And it appears to be ‘eating’ its host galaxy.
Our best estimates place the universe at about 13.8 billion years old. This black hole dates to a period only about 400 million years after the birth of the cosmos in the Big Bang.
At a few million times the mass of the Sun, the existence of the black hole is itself a mystery.
Professor Roberto Maiolino from the University of Cambridge, UK, lead author of a paper published in Nature which details the results, says the observation is “a giant leap forward.”
“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 says. “Very early galaxies were extremely gas-rich, so they would have been like a buffet for black holes.”
Conventional theories suggest that supermassive black holes – such as the ones in the centre of galaxies like our Milky Way – grow to their current size over billions of years as their gravitational pull sucks in surrounding stars and other material.
That such a big one existed in the early universe suggests that astronomers might have to rethink this.
Either supermassive black holes are “born big,” or they accumulate mass at a rate 5 times higher than what is currently believed.
The young host galaxy, GN-z11, is being consumed by the ancient supermassive black hole. GN-z11 is glowing from the accretion disc orbiting the black hole. The black hole itself is absorbing matter much faster than supermassive black holes at later epochs in the universe’s history.
GN-z11 is about 100 times smaller than the Milky Way. But the speed with which the black hole is consuming its host galaxy likely means it will kill the galaxy before it develops.
When a black hole consumes large amounts of gas, it results in a “wind” which could stop star formation. By slowly killing the galaxy, the black hole will also die by cutting its main source of matter accumulation.
The discovery was made possible by the JWST’s ability to see more detail in the early universe than ever before.
“It’s a new era: the giant leap in sensitivity, especially in the infrared, is like upgrading from Galileo’s telescope to a modern telescope overnight,” says Maiolino.
“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.”
