At the center of every galaxy in the universe sits a monster: a black hole millions or billions of times the mass of our Sun. When and how these massive objects formed is an open question in the astrophysical community.
Recently, A Paper Published in Nature In Astronomy, scientists announced the discovery of an ancient supermassive black hole that existed early in the universe’s life. Although some enthusiasts claim that the observation of these supermassive black holes disproves the Big Bang theory, this is a hasty conclusion. However, it is certainly true that the existence of very early supermassive black holes should make astronomers rethink some things.
Supermassive black holes
Most black holes are created when a very massive star burns through its fuel and then collapses under the weight of its own gravity. Stellar mass black holes are typically between 5 and 100 times the mass of the Sun.
In contrast, the supermassive black holes at the centers of galaxies are much more massive. The black hole at the center of the Milky Way galaxy known as Sagittarius A* (Sgr A*) has a mass equal to about 4.3 million suns. But even that pales in comparison to the most massive black hole known: 618 tonsFound at the center of a quasar, it weighs in at a staggering 66 billion solar masses.
How these supermassive black holes formed is still a mystery. While it’s an idea that individual stellar-mass black holes have merged, it’s hard to imagine that there’s been enough time since the universe began 13.8 billion years ago for enough mergers to account for the distribution of supermassive black holes. And it is difficult to even imagine that supermassive black holes formed at the beginning of the universe.
JWST has weight
The The James Webb Space Telescope (JWST) can image ancient galaxies, a few hundred million years after the universe began. In the aforementioned paper, the astronomers combined a JWST observation with discrete data Chandra X-ray Lab To identify a distant galaxy with a supermassive black hole. (When black holes absorb matter from their surroundings, the matter heats up as it falls inward and emits characteristic X-rays.)
Astronomers were surprised when they discovered that the mass of the black hole at the center of an ancient galaxy is about the same as the total mass of the stars in the same galaxy. (To put this in perspective, the supermassive black hole at the center of the Milky Way is only 0.1% the mass of the entire galaxy.)
Because this primordial supermassive black hole formed so quickly after the formation of the universe, it could not have been formed by a merger of stellar-mass black holes. Instead, another mechanism is required.
Gas black holes
State-of-the-art simulations suggest that early in the universe’s history, giant gas clouds may have collapsed directly into supermassive black holes — 100,000 times the mass of the Sun. These supermassive black holes are thought to have become supermassive black holes by merging and absorbing gas from their surroundings.
While this is an example of an ancient galaxy already hosting a supermassive black hole, others are expected to be discovered; After all, JWST only began operations in the summer of 2022. The data, reported in a recent paper, will help scientists get a better handle on what happened when the universe was in its infancy.
For example, ideal questions include: Whichever came first, supermassive black holes or galaxies? Did the galaxy attract nearby extragalactic gas that created the conditions that allowed supermassive black holes to form? Or did black holes form first and thereby draw in the gas that formed stars and galaxies? How did the heat generated by the gas flowing into early black holes affect star formation? What role did dark matter play in the process?
The answers to these and similar questions slowly come into focus.