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Crowd as a Fluid: The Physics of a Crush ⚡ экспресс

Original: "Exploring Dense Crowd Dynamics: State of the Art and Emerging Paradigms"
arXiv:2505.05826 · 2025-05-09 · CC BY 4.0 · ⏱ 1 min · Physics and Society
Physicists model crowds as a fluid, predicting dangerous compressions.
Abstract

A dense crowd is like a compressed spring: each shove passes from person to person, sometimes causing a dangerous crush. Researchers don't yet fully understand these hidden forces, so old crowd behavior models need rethinking. What if one day we could predict such situations, like meteorologists forecasting a thunderstorm?

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In tight spaces, a crowd behaves like water in a pipe: the more people, the higher the pressure. At the same time, entropy — a measure of chaos — increases, and a single push triggers a compression wave that, like gravitational waves, travels instantly through the crowd, knocking people off their feet. Previously, crowd movement was modeled as an ideal gas, ignoring physical contact. Now scientists account for compressive forces: at a density of more than 6 people per square meter, the lungs can't expand, and a person suffocates while standing upright. Such analysis helps architects design safer spaces. Surprisingly, a silent crowd is often more dangerous than a screaming one — silence hinders awareness of the threat until it's too late.

🎯 The highest recorded density is 9 people per square meter: the chest is compressed so much that breathing is impossible.

🎬 Asimov's psychohistory in real time.

Scientists
Jacob BekensteinStephen HawkingBernhard RiemannJoseph WeberKarl SchwarzschildKip Thorne
Tags
Water entropy gravitational waves
Laws
second law of thermodynamicsBekenstein-Hawking entropyEinstein field equationsBoltzmann distributionfirst law of thermodynamicsAdS/CFT correspondence
Original: arXiv:2505.05826 · CC BY 4.0 · bridge42worlds