“There’s No Going Back from This” James Webb Telescope Uncovers One of the Oldest Galaxies Ever Seen

James Webb Space Telescope Shakes Up Cosmology

A year ago, renowned American physicist Michio Kaku said that the James Webb Space Telescope (JWST) is “turning everything upside down.” Its observations may force us to rewrite textbooks about the beginning of the universe.

Galaxies like the Milky Way, with over 100 billion stars, take billions of years to form. Yet JWST has discovered six galaxies existing just half a billion years after the Big Bang, with sizes up to 10 times larger than the Milky Way. According to current theories, this shouldn’t happen.

Shocking Discovery: GZ9 P3 – An Ancient, Giant Galaxy

Two years after JWST’s successful launch, astronomers continue making groundbreaking discoveries, pushing the limits of what we can see. This time, JWST observed galaxies just 500 million years after the Big Bang, but these galaxies are far from “infantile”: they are extremely massive and more mature than expected.

One galaxy could be one of the oldest ever observed, containing billions of stars. Previously, Hubble only detected a faint speck of light in its field of view. Nobody imagined this was a massive galaxy. When JWST observed it, the speck turned out to be GZ9 P3, at a redshift of z = 9.3, meaning we are seeing it as it was 510 million years after the Big Bang.

Earlier, astronomers had observed galaxies forming around 3.5 billion years after the Big Bang, but none were as massive as GZ9 P3. This implies that stars within the galaxy must have formed faster and more efficiently than previously thought.

Strange Structure Reveals Early Universe Secrets

GZ9 P3 has a peculiar shape with two bright nuclei, indicating that two primordial galaxies collided in the early universe. Additionally, its stellar population is dominated by young, bright stars, but JWST also detected heavy elements like iron, silicon, and carbon in older stars.

Iron is the heaviest element stars can produce. When these stars explode, they spread these elements into space, contributing to the formation of new stars.
There are more old stars than expected, suggesting that galaxies reached chemical maturity faster than previously believed.

These findings challenge our current understanding of star and galaxy formation, showing that stars formed earlier and faster than thought.

Cosmological Crises: Hubble and S8 Tensions

This is not the only problem. There is a cosmology crisis: different methods of measuring the universe’s expansion rate – the Hubble constant (H₀) – give conflicting results:

Cosmic Microwave Background (CMB) method: measures light left over when the universe was 380,000 years old.
Standard candle method (Supernovae): compares the true brightness of distant supernovae with how bright they appear.

The difference between the two is called the Hubble tension. JWST has confirmed that this discrepancy truly exists, intensifying the crisis.

Another issue is the S8 tension, which measures how matter clusters in the present-day universe. Two methods – weak gravitational lensing (low redshift) and CMB-based standard model – do not match, showing that we still do not fully understand matter distribution.

Massive Universe Simulation: The FLAMINGO Project

To tackle the S8 tension, scientists used the Draco8 supercomputer at Durham University (UK) to run the largest universe simulation ever: FLAMINGO.

Over 50 million computing hours on 30,000 processors.
The simulation considers not only gravity but also ordinary matter, including galactic winds from supermassive black holes and supernova explosions.

Results:

Accurately models the formation of the Milky Way and Andromeda.
Yet it fails to explain the weak clustering of matter – S8 tension remains.
The model predicts galaxies 5–7% more clumped than observed, contradicting JWST and other telescope observations.

Conclusion: The Universe Remains Full of Mysteries

JWST and FLAMINGO show that:

Large galaxies can form rapidly and reach chemical maturity early.
Galaxy mergers may have been common just after the Big Bang.
Hubble and S8 tensions suggest our current theories may need revision, possibly requiring new physics.

Kaku emphasizes: “I’ve spent my life developing this theory, and now it’s being questioned. I welcome it because this is how science moves forward.”

The universe remains full of unsolved mysteries, and JWST is just the first step in uncovering the unknown.