“We have very good evidence of the distribution of matter from the cosmic microwave background in the early universe,” says Boylan-Kolchin. She calculated how much ordinary matter would have to enter the stars to explain the high-mass JWST galaxies. “Almost every atom in existence will be used to make stars,” he says.

According to Boylan-Kolchin, almost 100% efficiency is the limit of impossibility. “In today’s universe, it’s about 10%,” he says.

“The theoretical analysis in this paper is very solid,” says Mark Vogelsberger (MIT), who was not involved in the research. “There are not many assumptions in the calculations, which makes the results very reliable.”

If Boylan-Kolchin sums are correct, does this mean that ΛCDM is wrong? He’s not quite ready to give up yet. “No other theory can do what he did – knocking him down would be a last resort,” he says.

What else can be? A team led by Hayley Williams (University of Minnesota) has announced the discovery of an interesting early galaxy 500 million years after the Big Bang, again using JWST. It is so faint that it can only be seen by magnifying gravitational lenses. Williams found that the galaxy had a star formation rate ten times higher than galaxies 150 million years later. The results are published in: Science.

“This galaxy has a much lower mass than the galaxies we mentioned. [Бойлан-Колчін]”But if such a star could occur in larger galaxies at similar redshifts, it could help explain the strain in the standard cosmological model.”

Boylan-Kolchin isn’t so sure because this object is only 105 light-years across. Galaxies are often thousands of times larger. “Instead, it could be a globular cluster,” says Boylan-Kolchin.

There are other solutions to the problem, such as installing ΛCDM. A family of theories known as early dark energy (EDE) models predict a change in the behavior of dark energy (Λ in CDM) immediately after the Big Bang. This will help resolve another ongoing debate surrounding the Hubble constant. Reconciling this with other observations would require additional matter in the early universe. Boylan-Colchin calculated that in this case the density of matter in early galaxies would be 3 times higher, meaning that star formation would not need to be as efficient to achieve the same result. But EDE models suggest the universe is only 13 billion years old and contradict other measurements.

Astronomers may mistakenly attribute some of the light in galaxies to stars when it actually comes from accretion disks around supermassive black holes. “This is one of the most likely scenarios,” says Boylan-Kolchin.

Astronomers have seen only a few of these galaxies so far, and they all lie in a region that covers just a quarter-millionth of the sky. That doesn’t quite represent the entire cosmos. “We might well find out by doing more statistical research . . . “For that tension to go away,” says Joel Ledja (retd.), who was not involved in the study.

Maybe they’re not distant galaxies at all. “Nearby low-mass galaxies can mimic the appearance of distant massive galaxies,” says Peter Behrouzi (University of Arizona), who was not involved in the Boylan-Kolchin study. “No one can be trusted [сказати]Whether the results of this article are true or false until further measurements are made.

What is really needed are spectroscopic measurements of these galaxies. This will help soften their true distance and allow astronomers to look for signs of black holes. The good news is that this data is already coming in. “We really need to know if this is a serious issue in a few years, maybe less,” says Boylan-Colchin.

Astronomers have used the James Webb Space Telescope (JWST) to explore many large galaxies in the early universe, but they shouldn’t actually exist, according to a new study. Either astronomers got something wrong about the galaxies themselves or our pioneering model of cosmology is being challenged.

Despite being in space for less than 18 months, JWST provides unprecedented images of the universe in the first few hundred million years after the Big Bang. The big surprise was how quickly large, star-filled galaxies appeared.

Now, Michael Boylan-Kolchin (University of Texas at Austin) has looked at the problem from another angle and has published his findings in this book: Nature Astronomy. The leading cosmological model is known as ΛCDM, where CDM represents cold dark matter. According to the model, ordinary matter and dark matter mixed well in the early universe. When halos of dark matter disintegrated to form the first galaxies, some of the mixed ordinary matter was transformed into new stars.