JWST reveals ancient black holes and galaxies defying cosmic theories

The James Webb Space Telescope has revealed hundreds of puzzling “little red dots” that began appearing roughly 650 million years after the Big Bang, challenging astronomers’ understanding of the early universe. The objects, never seen before the telescope came online in 2022, are among several mysteries, including black holes that seem impossibly large for their age and ancient galaxies that defy established theories of cosmic evolution.

Astrophysicist Charlotte Mason of the Cosmic Dawn Center in Copenhagen analyzed the spectrum of light from one little red dot. If the objects are black holes cocooned in dense gas clouds, some light should be altered by passing through the gas, but her team’s analysis did not show this. Mason now suspects the gas may be clumpy, with holes that allow light to escape, which could better match observations.

Black holes spotted by JWST in the early universe have masses up to a billion times that of the sun, posing a major challenge to theorists. “In order to get them that big so quickly, you have to do some gymnastics,” said Jenny Greene, an astrophysicist at Princeton University. Standard stellar collapse would yield seed black holes of about 100 solar masses, but reaching a billion solar masses promptly requires “force-feeding” beyond the Eddington limit. Recent simulations indicate that super-Eddington accretion could happen if the accretion disk puffs up, allowing gas to funnel in at extraordinary rates. In 2024, JWST observed a black hole from about 1.5 billion years after the Big Bang accreting at 40 times the Eddington limit.

Another little red dot, dating to about 750 million years after the Big Bang and gravitationally lensed by a foreground galaxy cluster, was identified as a “naked” supermassive black hole roughly 50 million solar masses. Lacking discernible surrounding stars, this object may have formed through direct collapse of a gas cloud rather than from a stellar seed.

Early galaxies are also surprisingly bright. Rachel Somerville, a senior research scientist at the Flatiron Institute, presented new simulations at a meeting in Helsingør, Denmark, in April 2026. She explained that star formation ramps up significantly by about 420 million years after the Big Bang, and by 550 million years a “nice galaxy” emerges. The most ancient galaxy found by JWST existed only 280 million years after the Big Bang. Proposed explanations for the brightness include more efficient star formation, periodic bursts, or the creation of extremely massive stars.

JWST’s Mid-Infrared Instrument has revealed that early galaxies are unexpectedly diverse. Some appear to have cleared out gas and dust, showing only naked stars, while others remain gas-rich. An overabundance of nitrogen in certain galaxies suggests the presence of many very massive stars that exploded as supernovas, seeding galaxies with the element.

Such observations connect to the epoch of reionization, when radiation from the first galaxies and black holes ionized neutral hydrogen, ending the cosmic dark age. The first stars, thought to be hundreds or thousands of times more massive than the sun, forged heavy elements and scattered them through supernovas. “We’re looking back at what created us,” said Lise Christensen, an astrophysicist at the Cosmic Dawn Center.