When you read a late-night dispatch from an observatory in the desert or sit quietly in a planetarium, the scope of what astronomers are truly studying finally dawns on you. Viscerally, not intellectually. Those moments have been occurring at an unusually high frequency thanks to the James Webb Space Telescope. Furthermore, the most recent results from its ongoing surveys indicate that we are both humbled and genuinely perplexed about the universe we believed to be largely understood.
Cosmologists’ reactions to Webb’s initial images of the early universe ranged from excitement to apprehension. There were galaxies in the data that shouldn’t have been so big, bright, and developed—not at that age, not at that distance.
| Category | Detail |
|---|---|
| Telescope | James Webb Space Telescope (JWST) |
| Launched By | NASA, ESA (European Space Agency), CSA (Canadian Space Agency) |
| Launch Date | December 25, 2021 |
| Primary Mission | Observe early universe, detect infrared light from distant galaxies |
| Key Survey | CEERS — Cosmic Evolution Early Release Science Survey |
| Lead Researcher (CEERS) | Steven Finkelstein, Professor of Astronomy, UT Austin |
| Graduate Researcher | Katherine Chworowsky, University of Texas at Austin |
| Galaxy Discovered | MoM-z14 (“Mother of all early galaxies”) |
| Record Redshift | z = 14.44 — highest ever observed |
| Age of MoM-z14 | Light emitted ~280 million years after the Big Bang |
| Hubble Constant (Models) | ~67–68 km/s/Mpc (standard cosmology prediction) |
| Hubble Constant (Observed) | ~73 km/s/Mpc — confirmed by both Hubble and JWST |
| Key Finding on Galaxies | Black holes, not stars, responsible for extreme brightness of early galaxies |
| Standard Model Status | Not broken — but incomplete |
| Nobel Connection | Adam Riess, lead author on Hubble tension study, co-won 2011 Nobel Prize in Physics |
The standard model of cosmology, which is the fundamental theory of the universe’s composition and evolution since the Big Bang, may be crumbling, according to some researchers. It was a serious claim that spread widely and gained momentum in both the popular press and scientific journals.
However, a more realistic interpretation is provided by a recent study headed by University of Texas at Austin graduate student Katherine Chworowsky and published in the Astronomical Journal. Many of those seemingly enormous early galaxies are not as massive as they seemed, according to the analysis done by her team. Black holes are the culprit, and they’re surprisingly elegant. In particular, “little red dots” are compact, reddish objects with black holes in their centers that are consuming gas at extraordinary rates.
Intense heat and light are produced by friction in all that rapidly falling material, flooding the galaxy with brightness unrelated to the number of stars. When that black hole contribution is eliminated, the galaxies easily fit within current predictions. “We are still seeing more galaxies than predicted,” Chworowsky said, “although none of them are so massive that they ‘break’ the universe.”
At that point, there may be a slight sense of relief as well as a slight, lingering uneasiness. Because the study subtly confirms that there are still about twice as many massive galaxies in the early universe as standard models would predict, even after accounting for black holes. That gap still exists. It’s just less frightening now.
One popular theory holds that stars formed exceptionally quickly in the early universe because of the denser, more crowded conditions of those first hundreds of millions of years, which made it more difficult for gas to escape before collapsing into stars and significantly accelerated the process. Chworowsky hypothesized, “Maybe in the early universe, galaxies were better at turning gas into stars.” It makes sense as a theory. The next twelve questions are also raised by it.
Then there is MoM-z14, which was discovered at the highest known redshift of z = 14.44. Often referred to as the “Mother of all early galaxies,” this galaxy began to emit light only 280 million years after the Big Bang. That in and of itself is amazing. Its chemical makeup, however, was what truly alarmed researchers. It has nitrogen and carbon in it.
These kinds of elements need to be processed and dispersed by earlier star generations before they can arise from the universe’s primordial hydrogen. This indicates that the universe had already gone through at least one generation of star birth and death at a time when most models predicted only the faintest, most primitive structures. In the words of Yale University’s Pieter van Dokkum, “JWST is showing that we underestimated the young universe — and maybe we still are.”
That sentence has a peculiar quality to it. Even though astronomy has always been at ease with enormous scales, such as billions of years or billions of light-years, it is still startling to learn that the universe was operating more quickly and forcefully than we had anticipated before we even had models for what it was supposed to be doing.
Despite being 50 times smaller than the Milky Way, MoM-z14 is producing stars at a rate that shouldn’t be achievable considering its size and age. One gets the impression that the early universe was not a slow, tentative experiment by observing this develop in the data. It was already operating at maximum speed.
Then there is the Hubble tension, which is arguably the most enduring issue in contemporary cosmology. The cosmos is growing. Since the early twentieth century, this much has been known. However, how you measure it will determine how quickly it is growing. A Hubble constant of between 67 and 68 km/s per megaparsec is consistently suggested by models based on the early universe. Using Cepheid variable stars as distance markers, a technique regarded as the gold standard, direct observations of the modern universe continue to approach 73. Measurement noise is not the cause of that gap. T
he Hubble telescope’s measurements were verified using JWST data in a recent study headed by Adam Riess, whose 1998 discovery of the universe’s accelerating expansion earned him a share of the 2011 Nobel Prize in Physics. The same disparity. The same unwavering 73. “With two NASA flagship telescopes now confirming each other’s findings,” Riess said, “we must take this problem very seriously.”
The most promising explanations for the tension are not particularly neat. It’s possible that dark energy, which cosmologists estimate makes up about 68% of the universe and is thought to be responsible for its expansion, is acting in ways that current models are unable to explain. Additionally, early dark energy—some unidentified substance that provided the universe with an extra boost soon after the Big Bang—is a possibility.
Researchers are being urged to think creatively about exotic particles, primordial magnetic fields, and shifting electron mass, which is both an invitation and an indication that there isn’t yet a definitive solution. Riess admitted to Reuters, “Our understanding of the universe contains a lot of ignorance about dark matter and dark energy.” “And these make up 96 percent of the universe.”
When all of this is considered, the result is neither a crisis nor consolation. The black hole explanation for the early galaxy problem supports the standard model of cosmology, which has withstood tremendous pressure. “Any time you have a theory that has stood the test of time for so long, you have to have overwhelming evidence to really throw it out,” stated Steven Finkelstein, director of the CEERS survey. And that’s just untrue.” That’s a reasonable evaluation. It’s also true that galaxies continue to form more quickly than anticipated, the Hubble tension is still unresolved, and the universe seems to have matured more quickly than its own birth certificate would indicate.
Reading these results makes it difficult to ignore the fact that the James Webb Space Telescope is doing precisely what the best instruments always do, which is to reveal the shape of what we don’t yet know rather than offering precise answers. Maybe Chworowsky best expressed it. “Not everything is fully understood,” she stated.
“That’s what makes doing this kind of science fun, because it’d be a terribly boring field if one paper figured everything out, or there were no more questions to answer.” That seems correct. Furthermore, it’s obvious that there are still a lot of unanswered questions given what Webb continues to uncover.
