In the past several years, new findings from the James Webb Space Telescope, launched in 2021 by NASA and positioned nearly a million miles from Earth, are posing crucial questions about the early universe.
When the telescope began delivering deep-field images in late 2022, astronomers noticed countless tiny red specks scattered across the distant background. These objects—soon nicknamed “little red dots” (LRDs)—appear to date from between roughly 600 million and 1.5 billion years after the Big Bang. Their color is intensely red, and this is caused in part by immense cosmic redshifting (the stretching of light over time). However, what exactly causes the intrinsic redness of the little red dots is still currently a matter of debate in the astronomical community. They are prominent in JWST images because the telescope is specifically designed to detect infrared light (which was previously invisible to the Hubble Space Telescope).
In January 2026, researchers at the Harvard-Smithsonian Center for Astrophysics presented findings at the 247th meeting of the American Astronomical Society suggesting that some of these little red dots could be gigantic, short-lived stars (specifically, “supermassive non-metallic primordial stars”). Competing theories propose that they may instead represent an early phase in the growth of supermassive black holes.
“Little red dots have become, quite unexpectedly, the hottest topics in astrophysics today,” says astrophysicist Fabio Pacucci. He and his colleagues at the Center for Astrophysics submitted a paper last February arguing that these dots could be identified as Direct Collapse Black Holes—gigantic black holes of 100,000 to 1 million times the mass of the sun, formed when the universe was very young.
One thing remains true across theories: LRDs appear within the first billion years of the universe yet seem too large and mature for that epoch. This paradox is challenging our current cosmological model and stirring up new thought among astronomers and astrophysicists.
1. How do black holes influence the universe?
A black hole is what remains when gravity triumphs. When a very massive star exhausts its nuclear fuel, it can no longer support its own weight. The core collapses, space and time curve inward without limit, and an event horizon forms: a boundary beyond which not even light can return. The black holes formed in this way weigh a few times the mass of our sun. There are also far larger black holes, millions or billions of times the sun’s mass, that sit at the centers of galaxies. We believe those grew over cosmic time by accreting gas and merging with other black holes.
Despite their reputation as cosmic vacuum cleaners, black holes are not primarily destroyers. They are engines. As matter spirals inward, it heats and releases enormous energy, sometimes outshining entire galaxies. In this way, a central black hole can behave like a thermostat, regulating star formation and shaping the evolution of its host galaxy. On the largest scales, they help sculpt the visible universe, turning gravity’s most extreme triumph into a source of structure and light.
2. Black holes are invisible. So how do astronomers detect them?
Black holes are invisible in the same way that wind is: one can infer their presence by what they move and the energy they unleash. A lone black hole drifting through empty space would be almost impossible to detect. But they are, in fact, the most efficient engines in the universe at transforming matter into light. They can radiate across the entire electromagnetic spectrum, from radio waves to visible light to powerful X-rays, sometimes outshining all the stars in their host galaxy.
In the early universe, that light is stretched by cosmic expansion into the infrared. This is where the James Webb Space Telescope has transformed the field. It is much more sensitive than Hubble, but it also extends its reach deep into the infrared, an electromagnetic range Hubble could only partially access, allowing us to detect black holes forming only a few hundred million years after the Big Bang.
3. Why did little red dots immediately stand out as puzzling to researchers?
They appear less than a billion years after the Big Bang and are astonishingly compact, often only a few hundred light-years across—the Milky Way is more than a hundred times larger. They are bright in the infrared and often show broad emission lines in their spectra—signatures typically associated with gas moving at thousands of kilometers per second around a central supermassive black hole. And yet, they are faint or invisible in X-rays, where actively feeding black holes usually shine.
They stood out immediately because they do not fit comfortably into existing astrophysical categories. They are either implausibly dense stellar systems—packing a galaxy’s worth of stars into a tiny volume—or they host overmassive black holes that defy well-known scaling relations.
3. How does that challenge existing models of black hole formation and growth?
If the little red dots truly host rapidly accreting black holes, they strike at the heart of one of the biggest debates in cosmology: how the first black holes were born. In the “light seed” scenario, black holes begin as the remnants of the first stars—a few tens or hundreds of solar masses—and then grow through sustained, often extreme accretion. The alternative is the “heavy seed” pathway, in which massive, pristine gas clouds collapse directly into black holes of about 100,000 solar masses, bypassing the stellar phase altogether. These objects, called direct collapse black holes, are the Holy Grail of astrophysics.
In our recent work, we show that the distinctive properties of the little red dots—broad emission lines, weak X-ray emission, extreme compactness—are naturally reproduced if they are accreting direct-collapse black holes enshrouded in very dense gas. In this view, the Webb telescope may be witnessing the birth of heavy seeds themselves during a brief, previously hidden phase of cosmic history.
4. How might this influence our understanding of galaxies and black holes?
In our framework, a heavy seed forms early, accretes for more than 100 million years in a gas-rich environment, and only later does the surrounding galaxy assemble substantial stellar mass. If this picture is correct, galaxies like the Milky Way may carry the fossil record of such an early phase. The familiar co-evolutionary balance we observe today may be the end result of an initially unbalanced beginning, when black holes briefly ran ahead of their galaxies. Overall, we may finally be on the verge of answering one of the most fundamental questions in astrophysics: did black holes form first, or did galaxies?
