Primordial Dark Energy Hand

Dark energy may have caused many bright galaxies to form very early in the universe, according to a new study. The mysterious and unknown force may have caused the seeds of the first galaxies (pictured left) to sprout more bright galaxies (right) than theory predicted. Credit: Josh Burrow/Theisan Team

According to New Studio Conducted by physicists with It was published last week in the magazine Monthly Notices of the Royal Astronomical Societyforprimordial dark energy It could solve two of the biggest puzzles in modern cosmology and fill some important gaps in our current understanding of how the universe evolved. One puzzle under investigation is the Hubble lineage, a discrepancy in measurements of the universe’s expansion rate. The other concerns recent observations of many bright galaxies, particularly early galaxies, that were already around at a time when the universe should have been much less populated.

to’Dark energy It’s an unknown form of energy that’s suspected to be driving the expansion of the universe. Primordial dark energy, researchers hypothesize, is similar to dark energy, but it only appeared briefly in the universe, affecting its expansion in its first moments, before disappearing completely. That brief glimpse was enough to justify Hubble’s jitters. What’s more, it also seems to explain the exceptionally large number of bright galaxies observed in the early universe.

In fact, based on cosmological and galaxy formation models, the universe should have taken a certain amount of time to give birth to the first galaxies, longer than what was found in observations by the James Webb Space Telescope (JWST), which instead revealed a staggering spike of bright galaxies, the size of the Milky Way, in the first 500 million years, when the universe was only 3% of its current age.

For physicists, these observations suggest that there is something fundamentally wrong with the physics on which the models are based. Missing ingredient in the early universe That’s something scientists haven’t taken into account. The MIT team explored the latter possibility, postulating this new form of dark energy, a kind of anti-gravity force that only activates at very early times. This force would counteract the pull of gravity and accelerate the primordial expansion of the universe.

The researchers then considered how primordial dark energy influenced the early structure of the universe that gave rise to the first galaxies, focusing on the formation of dark matter halos—regions of space where gravity is strongest and where matter begins to accumulate. “We think of dark matter halos as the invisible skeleton of the universe,” he explains. With the news Xuejian (Jacob) Shenco-author of the study. “First, dark matter structures form, and then galaxies form within these structures. Thus, we expect the number of bright galaxies to be proportional to the number of large dark matter halos.”

According to the authors, if primordial dark energy affected the initial expansion rate of the universe—in a way that solved the Hubble tension—it could have affected the balance of other cosmological parameters, increasing the number of bright galaxies that appeared early. To test their theory, they incorporated the primordial dark energy model (the same model that solves the Hubble tension) into a model Experimental framework for galaxy formationTo learn how early dark matter structures evolved and gave rise to the first galaxies.

“What we show is that the structure of the early universe changed in subtle ways where the amplitude of fluctuations increased, and you got bigger halos and brighter galaxies at earlier times, compared to our most common models,” says Rohan Naidoo. “This means that in the early universe things were more abundant and more compact.”

“We have demonstrated the potential of primordial dark energy as a solution to the two major problems in cosmology,” he concludes. “If the James Webb Space Telescope observations are further strengthened, it could be evidence of its existence.” Mark Vogelsberger“In the future, we can incorporate it into large cosmological simulations to see what detailed predictions we get.”

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