For decades, astronomers have believed that galaxies came first and black holes came later.
In the traditional picture, stars form inside a galaxy, some of those stars eventually collapse into black holes, and over time the black holes grow larger by merging with others and consuming surrounding matter.
But a remarkable new discovery from NASA’s James Webb Space Telescope is challenging that idea.
Researchers have found evidence that some supermassive black holes may have formed before their host galaxies, suggesting that these enormous cosmic objects were born large rather than growing gradually from smaller black holes.
The discovery centers on an object known as Abell2744-QSO1, or QSO1, a member of a mysterious class of objects called “Little Red Dots.” QSO1 existed just 700 million years after the Big Bang, making it one of the earliest known black hole systems in the universe.
Scientists were able to study QSO1 in unusual detail because its light was magnified by a phenomenon called gravitational lensing. A massive galaxy cluster known as Pandora’s Cluster bends and amplifies the object’s light, making it appear brighter and easier to observe.
Earlier observations suggested that QSO1 contained a supermassive black hole about 40 million times the mass of the Sun. However, researchers wanted a more direct way to measure its mass rather than relying on assumptions based on nearby black holes.
Using Webb’s Near Infrared Spectrograph, the team tracked the movement of hydrogen gas swirling around the black hole. They discovered that the gas follows a pattern known as Keplerian motion, similar to how planets orbit the Sun. This motion allowed the scientists to directly calculate the black hole’s mass for the first time in such an early cosmic object.
The results were striking. The black hole was found to have a mass of about 50 million Suns and accounts for at least two-thirds of the total mass of QSO1. In modern galaxies, supermassive black holes usually make up only a tiny fraction of the galaxy’s mass.
Researchers also examined the chemical makeup of the gas surrounding the black hole. They found that it consists almost entirely of hydrogen and helium, with very little oxygen or other heavier elements. Since heavy elements are produced by stars, their absence suggests that QSO1 contains very few stars and has undergone little stellar evolution.
Together, these findings indicate that the black hole likely did not grow slowly from smaller stellar black holes. Instead, it may have formed as a massive “heavy seed” shortly after the Big Bang or emerged from the direct collapse of a giant cloud of gas.
If this interpretation is correct, the black hole may have existed before a substantial galaxy formed around it. In other words, rather than a galaxy creating a black hole, the black hole may have helped build the galaxy.
Scientists are now studying other Little Red Dots to determine whether QSO1 is unusual or whether giant black holes commonly appeared before galaxies in the early universe. If confirmed, the discovery could fundamentally change our understanding of how the first galaxies and black holes formed.
The findings were published in Nature and Monthly Notices of the Royal Astronomical Society.
Source: NASA.
