For decades, astronomers faced a "chicken and the egg" problem: did galaxies form first, with stars eventually collapsing into black holes at their centers, or did black holes act as the "seeds" that gathered galaxies around them?
Recent data from the James Webb Space Telescope (JWST), released throughout 2024 and 2025, has dramatically shifted the scales. The evidence now suggests that supermassive black holes came first, or at the very least, they emerged much earlier and grew much faster than our previous models of galaxy formation allowed.
1. The Classical View: Galaxies First
Until recently, the standard model—often called the "Bottom-Up" model—suggested that the universe began with small clumps of gas and dark matter.
Star Birth: These clumps formed the first stars.
Galaxy Assembly: Small groups of stars merged to form "protogalaxies."
Black Hole Formation: Only after massive stars died and collapsed did "seed" black holes form. Over billions of years, these seeds merged and fed on gas to become the supermassive giants we see today.
Under this theory, the black hole was a consequence of the galaxy’s growth.
2. The New Paradigm: Black Holes as "Building Blocks"
The JWST has turned this timeline on its head by spotting "monsters" in the early universe. Scientists have discovered supermassive black holes (SMBHs) existing just 400 to 500 million years after the Big Bang. These black holes are far too large to have grown from "normal" star deaths in such a short time.
The "Direct Collapse" Theory
Current research suggests that instead of forming from a single dying star, these early black holes formed through Direct Collapse. In the dense, hot environment of the infant universe, massive clouds of gas may have collapsed directly into a black hole without ever forming stars first. This gave the black holes a massive head start—beginning their lives at $10,000$ to $1,000,000$ times the mass of our Sun.
Black Holes as Star Factories
New analysis (notably by teams at Johns Hopkins University in 2024-2025) suggests black holes didn't just exist first; they birthed the galaxies.
Outflows: As these early black holes "fed" on surrounding gas, they emitted powerful winds and magnetic storms.
Compression: These winds crushed nearby gas clouds, triggering a violent burst of star formation.
Result: The black hole acted as a catalyst, accelerating the creation of a galaxy around itself.
3. Comparing the Timelines
| Feature | Classical Theory (Galaxies First) | Modern Theory (Black Holes First/Co-evolution) |
| Primary Driver | Gravity of dark matter and gas. | "Seed" black holes from direct collapse. |
| Role of Black Hole | A passive resident that grows slowly. | An active "engine" that triggers star birth. |
| Observation | Predicted small black holes in early times. | Found massive black holes in early times. |
| Galaxy Appearance | Dim and slow-growing. | Surprisingly bright and mature (as seen by JWST). |
4. The "Little Red Dots" Mystery
One of the most compelling pieces of evidence from 2025 is the discovery of "Little Red Dots." These are extremely compact, red galaxies from the dawn of time. Observations show they host black holes that are "too big" for their host galaxies—sometimes making up a huge percentage of the galaxy's total mass. In our modern Milky Way, the central black hole is only about 0.01% of the total mass. In these early "Little Red Dots," the ratio is significantly higher, proving that the black hole growth significantly outpaced galaxy growth.
Summary: A Mutual Birth
The consensus in 2025 is moving toward a Co-evolution Model, but with the black hole as the primary spark. While dark matter provided the "cradle," the supermassive black hole provided the "fire" that lit up the first galaxies. They likely formed nearly simultaneously, but the black hole's influence was the dominant force that determined how—and how fast—the galaxy grew.