The James Webb Space Telescope (JWST) detected a colossal early-universe galaxy, challenging cosmology. Galaxy ZF-UDS-7329 formed 800 million years without dark matter, disrupts standard models.

This discovery, akin to previous JWST findings, may revolutionize the current understanding of early matter formation.

(Photo : Wikimedia Commons/ESA/Hubble & NASA, RELICS)
Zooming in on the early Universe

JWST Observes ZF-UDS-7329

The constant speed of light in the vacuum of space allows us to peer deeper into the universe, capturing more distant and ancient light. The JWST utilized this principle to observe ZF-UDS-7329, locating it approximately 11.5 billion years in the past.

Analyzing the starlight spectra from this exceedingly distant galaxy revealed that its stars originated 1.5 billion years before the observation, placing their birth around 13 billion years ago. The timeline of the first stellar clusters forming into galaxies remains uncertain, but previous estimates suggested a gradual process starting within a few hundred million years after the Big Bang.

Conventional theories propose that dark matter halos, combined with gas, formed the initial galaxies. Protogalaxies then evolved into dwarf galaxies, engaging in a period of mergers and growth resembling that of our Milky Way.

However, the newfound galaxy challenges this narrative by crystallizing without the expected accumulation of sufficient dark matter. Furthermore, after a sudden burst of star formation, it entered a quiescent phase, abruptly ceasing star formation.

Themiya Nanayakkara, an astronomer at Swinburne University, emphasized the collaborative effort, spanning infrared sky surveys, failed attempts at confirmation with ground telescopes, and the breakthrough analysis of Webb data. The researchers plan to search for similar galaxies, anticipating potential contradictions to established ideas about galaxy formation.

READ ALSO: Very Extreme Galaxy in the Early Universe Hosts a New Type of Primordial Black Hole

Massive Early Universe Galaxies Challenge Cosmology

The discovery of extremely massive galaxies in the early universe is challenging established cosmological theories, according to Claudia Lagos, an associate professor of astronomy at the International Centre for Radio Astronomy Research. These galaxies, like ZF-UDS-7329, defy expectations as the massive dark matter structures thought to be essential for holding them together did not have sufficient time to form in the early universe.

Galaxy formation, a cornerstone of modern astrophysics, predicts a decline in massive galaxies in early cosmic times. However, observations now reveal quiescent galaxies appearing just 1-2 billion years after the Big Bang, contradicting previous theoretical models.

Professor Karl Glazebrook from Swinburne University of Technology highlighted the seven-year pursuit of understanding ZF-UDS-7329, involving extensive observations with Earth's largest telescopes and ultimately confirming its nature using the James Webb Space Telescope (Webb).

Dr. Nanayakkara highlighted the discovery's impact on our understanding of galaxy formation and evolution, questioning the mechanisms behind the rapid early universe galaxy formation and the sudden cessation of star formation. This achievement expands our understanding of the earliest massive quiescent galaxies in the universe, pushing the boundaries of current knowledge in galaxy formation and evolution.

The pressing question arising from these findings is the rapid formation of such massive galaxies in the early universe and the mysterious mechanisms that lead to their abrupt cessation of star formation. The role of dark matter concentration in dictating galaxy formation becomes crucial, highlighting the need to reassess our understanding of the universe's early stages.

The findings of the study, titled "A massive galaxy that formed its stars at z ~ 11," are published in the journal Nature.

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