Dark matter isn’t so cold after all ⚡ экспресс
A comprehensive cosmological analysis is performed on an effective non-standard dark matter model with an equation of state w_dm = w₂ a², allowing a slight departure from the pressure of standard cold dark matter. This model is paired with three single-parameter dark energy scenarios: a freezing scalar field, modified emergent dark energy (MEDE), and constant w. Constraints are derived using Planck 2018 CMB (distance priors), baryon acoustic oscillations from DESI DR2, and three compilations of Type Ia supernovae (DESY5, Union3, PantheonPlus). In all combinations of dark energy models and datasets, a robust preference for negative values of the parameter w₂ is observed. This indicates that dark matter possesses a small but non-zero negative pressure—i.e., a non-cold nature. Although the inferred Hubble constant H₀ remains compatible with the Planck ΛCDM result and does not fully resolve the tension with local measurements, the consistent detection of w₂ < 0 across a wide range of independent probes provides compelling evidence for new physics in the dark matter sector.
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.