A new study led by Colgate assistant professor of physics and astronomy Cosmin Ilie, in collaboration with Jillian Paulin ’23 of the University of Pennsylvania, Andreea Petric of the Space Telescope Science Institute, and Katherine Freese of the University of Texas at Austin, proposes a single idea that could solve three major mysteries of the universe’s earliest era. Scientists suggest that dark stars may help explain the appearance of unexpectedly bright “blue monster” galaxies, the presence of very massive black holes at extremely early times, and strange objects known as “little red dots” seen in images from the James Webb Space Telescope (JWST).
The earliest stars formed in regions dominated by dark matter, specifically in the centers of small dark matter structures called microhalos. A few hundred million light-years after the Big Bang, clouds of hydrogen and helium cooled enough to begin collapsing under their own gravity. This process led to the birth of the first stars and marked the beginning of the cosmic dawn, a formative period in the history of the universe.
During this time, conditions may have allowed a rare type of star to form. These stars could be powered not only by nuclear fusion, but also by the energy released in the annihilation of dark matter particles. Such objects, known as dark stars, can grow to enormous sizes and can naturally evolve into seeds that later become supermassive black holes.
JWST reveals unexpected early galaxies
JWST has now observed the most distant objects ever studied, offering an unprecedented view of the early universe. These observations challenged long-held theories about how the first stars and galaxies formed. One of the most surprising findings is the large population of galaxies known as “blue monsters”. These galaxies are extremely bright, very compact, and contain little or no dust.
Before JWST, no simulations or theoretical models predicted that galaxies with these properties should exist so early in the history of the universe. Their discovery forced astronomers to reconsider how quickly stars and galaxies could form.
Excessive black holes and small red dots
The JWST data also added to the ongoing mystery involving supermassive black holes. Some of the earliest observed galaxies appear to host black holes that are much larger than expected given their age. Explaining how the seeds of these larger-than-expected supermassive black holes (SMBHs) formed so quickly remains a major challenge.
In addition, JWST revealed a new category of compact objects known as “small red dots” (LRDs). These dust-free sources date back to the cosmic dawn and are unusual in that they emit almost no X-rays, something astronomers had not predicted based on existing models.
Why current models are inadequate
Together, the blue monster galaxies, early supermassive black holes, and small red dots point to serious gaps in theories of the formation of early galaxies and black holes before JWST. The findings suggest that widely accepted models need substantial updates to match what JWST is now seeing.
“Some of the most significant mysteries presented by the JWST Cosmic Dawn data are actually features of the dark star theory,” Ilie said.
Growing evidence for dark stars
Although dark stars have not yet been confirmed by direct observation, a new study confirms their existence. It builds on photometric and spectroscopic dark star candidates identified in two separate PNAS studies published in 2023 and 2025.
The authors detail how dark stars could explain the properties of blue monster galaxies, small red dots and early galaxies hosting massive black holes. The paper also presents the latest spectroscopic analysis that provides evidence for the characteristic helium absorption features in the JADES-GS-13-0 spectrum. A similar feature was previously identified in JADES-GS-14-0.
Why dark stars matter
Dark stars are among the most interesting theoretical objects of modern astrophysics. If confirmed, they could offer a way to directly probe the properties of dark matter particles. This would complement ongoing efforts to detect dark matter in laboratory experiments on Earth, either through direct detection or particle production, and could help connect space observations with fundamental physics.
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