Dark matter isn’t so cold after all express

Original: "Effective dark matter component presents a robust signature of negative pressure by the DESI observations"
· Hao Xu, Xinhe Meng
arXiv:2601.01340v1 · 2026-01-04 · CC BY 4.0 · 1 min
New analysis reveals: dark matter isn’t entirely passive — it has a tiny negative pressure.

The enigma of dark matter was already studied by Fritz Zwicky and Vera Rubin. For decades, it was depicted as a cold, listless skeleton that only draws galaxies together. A fresh look at data from supernovae, dark energy, and measurements of the universe’s expansion hints that this skeleton not only holds but also flexes gently, pushing itself apart. This effect, negative pressure, is billions of times weaker than the familiar gravitational attraction of particles, yet it reshapes the notion of dark matter’s passive nature. Researchers emphasize that the finding doesn’t depend on the chosen dark energy model. Maybe the standard cosmological model will soon embrace new physics, even though the mystery of the universe’s differing expansion rates remains unsolved.

Negative pressure is a minuscule self-repulsion, billions of times weaker than the gravitational pull we're used to.

Sci-fi writers have long exploited negative pressure for space jumps; now it turns out dark matter itself contains this ingredient, albeit in tiny doses.

Scientists
Fritz ZwickyVera RubinAdam RiessSaul PerlmutterBrian SchmidtRobert H. Dicke
Concepts
dark matter properties lcdm model dark matter detection equation of state parameter ecdm model Witten's positive energy theorem cosmological parameters density profile manganese null energy condition dimensionless parameter desi lambda cdm dysprosium cold dark matter fermionic dark matter