Simple

River as a Mirror of the Universe ⚡ экспресс

Original: "Laboratory rivers extremize friction and are cosmological analogues"
· Valerio Faraoni, Nikki Veilleux
arXiv:2605.14670v1 · 2026-05-14 · CC BY · ⏱ 1 min · Geophysics General Relativity
The profile of a riverbed follows the same equation as the expansion of the Universe.
Abstract

Scientists have found that the cross-sectional shape of a riverbed is described by the same equation that governs the evolution of the Universe. And it's no fluke — this shape maximizes the friction of water against the bottom. What other secrets do earthly streams and distant galaxies share?

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The shape of a riverbed precisely follows the equation describing the growth of a universe with negative curvature. In the lab, water flowing over sand spontaneously carves a cross-section that matches the solution for the Anti-de Sitter model.

A river tends toward a shape that maximizes bottom friction. Counterintuitively, water chooses a channel that accelerates energy dissipation (increasing entropy). Sand and water find an equilibrium that’s described by the same law governing the expansion of the entire Universe.

This discovery helps predict river changes and design canals. But the real magic is that a laboratory river becomes a mirror reflecting the mathematics of the cosmos. The flow of water carries the same harmony that Lemaître and Einstein found in the expansion of the Universe.

🎯 In a laboratory river, sand and water eventually settle into the very shape that most strongly slows the flow — as if by mutual agreement, without any outside interference.

Scientists
Adam RiessBrian SchmidtEdwin HubbleGeorges LemaîtreMaarten SchmidtSaul Perlmutter
Tags
spacetime curvature Water entropy expansion of the universe
Laws
Hubble's lawsecond law of thermodynamicsBekenstein-Hawking entropyBoltzmann distributionfirst law of thermodynamicsequivalence principle
Original: arXiv:2605.14670v1 · CC BY · bridge42worlds