When the universe was born in chaos: how cosmic turbulence forged the first stars

The early universe was not a quiet nursery. New high-resolution simulations published in 2026 reveal that the primordial dark matter halos where the universe’s first stars were born were not calm, smooth environments — they were violent arenas of supersonic turbulence, with gas plunging inward at speeds five times the sound barrier.

The study, led by researchers at the Institute of Astronomy and Astrophysics of Academia Sinica (ASIAA) in Taiwan, used the GIZMO hydrodynamic code combined with initial conditions extracted from the IllustrisTNG cosmological simulation. The team simulated 15 primordial minihalos with masses ranging from 100,000 to 10 million solar masses, at redshifts between 17 and 20 — a cosmic epoch roughly 200 million years after the Big Bang, when no star had yet ignited anywhere in the universe.

Turbulence as a sculptor of stellar birth

What these simulations captured for the first time is the full development of supersonic turbulence during the assembly of a dark matter minihalo. As gas falls into the gravitational well of these ancient structures, it does not settle gently. Instead it converges along filaments at high velocity, generating shocks and chaotic flows with Mach numbers reaching up to 4.2 — meaning the gas moves more than four times faster than the local speed of sound.

This turbulence is not destructive. Counterintuitively, it acts as a sculptor: it breaks the primordial gas cloud into dense clumps. One of those clumps surpassed the Jeans instability threshold and began collapsing — not into a massive giant, but into a star of roughly 8 solar masses.

Rewriting the story of Population III stars

Standard theoretical models predicted that Population III stars — the universe’s first generation — formed in near-total isolation, with masses between 80 and 260 solar masses. These hyper-massive stars were expected to die as pair-instability supernovae, leaving a distinctive chemical imprint in the oldest stars we can observe today. Yet despite decades of searching, no such signature has been conclusively found.

The new simulations offer a compelling explanation: the first stars were not solitary giants. Turbulence fragmented their birth clouds into multiple, less massive objects. Stars below roughly 50 solar masses do not explode as pair-instability supernovae and leave no such fingerprint. The absence of that evidence is not a mystery — it is confirmation that our models needed revision.

A resolution that changes everything

The key technical achievement here is scale. Previous simulations used cosmological boxes of only 0.3 to 2 megaparsecs. This work draws from IllustrisTNG’s 50-megaparsec volume, then applies a particle-splitting technique that boosts resolution by a factor of 100,000 — reaching individual gas particle masses of 0.2 solar masses. This allowed the team to trace turbulence arising purely from gravitational infall, without assuming what it should look like in advance.

What shaped the very first stars was not the orderly collapse of pristine gas, but the same chaotic, turbulent physics that governs star formation today. Cosmic dawn was not a quiet event. It was a storm.

© 2026 SKYCR.ORG | Homer Dávila Gutiérrez, FRAS. All rights reserved. Reproduction in whole or in part without express authorization is prohibited. More information The Astrophysical Journal (2026). DOI: 10.3847/1538-4357/ae731d