Webb telescope detects ancient, massive galaxies that shouldn't exist

One galaxy from 13 billion years ago rivals the Milky Way’s mass but is far smaller.

Key Takeaways

The James Webb Telescope has spotted massive galaxies from over 13 billion years ago.
These early galaxies are as massive as the Milky Way but 30 times more compact.

Discovered galaxies may have formed only 500-700 million years after the Big Bang.
The rapid formation of these galaxies defies current cosmological theories.
Researchers are excited about the possibility of uncovering more surprising phenomena with Webb.

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Unprecedented Discoveries by the James Webb Telescope

The James Webb Space Telescope has uncovered six candidate galaxies that existed 500 to 700 million years after the Big Bang, making them more than 13 billion years old. These massive galaxies challenge existing cosmological theories due to their immense size and rapid formation. Erica Nelson, co-author of the study and astrophysics professor at CU Boulder, expressed amazement at how these galaxies could organize themselves so quickly.

The galaxies, detected in Webb’s Cosmic Evolution Early Release Science (CEERS) Survey, each contain as many stars as the modern Milky Way but are significantly more compact. One galaxy alone harbors tens of billions of stars while being 30 times smaller than our galaxy. The findings, led by Ivo Labbé of the Swinburne University of Technology, were published in Nature.

A mosaic collected by James Webb of a region of space close to the Big Dipper, with insets showing the location of six new candidate galaxies from the dawn of the universe. Credits: NASA, ESA, CSA, I. Labbe (Swinburne University of Technology). Image processing: G. Brammer (Niels Bohr Institute’s Cosmic Dawn Center at the University of Copenhagen).

Galaxies That Shouldn’t Exist

These galaxies likely formed during the dawn of the universe when there was not enough matter to produce stars at such a rapid pace. For comparison, the Milky Way forms one to two stars annually, while these ancient galaxies would have needed to create hundreds of stars each year to reach their size. The discoveries highlight the unexpected complexity of the early universe.

Astronomers rely on the redshift of light to estimate the galaxies’ age and distance. The deep red color indicates their light traveled for billions of years, stretched by the expanding universe. These findings hint that the early universe evolved far more rapidly than previously thought.

Researchers acknowledge that further analysis is necessary to confirm the galaxies’ age and mass. Alternative explanations include them being faint quasars or entirely new phenomena. However, even one confirmed galaxy would push the limits of our understanding of cosmology.

Artist’s depiction of the James Webb Space Telescope. (Credit: NASA GSFC/CIL/Adriana Manrique Gutierrez)

A Telescope That Sees Back in Time

The James Webb Telescope is following in the groundbreaking footsteps of the Hubble Telescope. Hubble, launched in 1990, first suggested that galaxies formed earlier than expected. Similarly, Webb’s discoveries could redefine the timeline of cosmic evolution.

For Nelson, who has been fascinated by space since childhood, Webb’s rapid pace of discovery is a dream come true. The telescope offers a time machine, allowing astronomers to look back billions of years and uncover the universe’s secrets. “I’m so excited,” Nelson said, reflecting on how these discoveries challenge established theories and open new avenues for exploration.