Study Finds Fundamental Physical Constants Constrain Liquid Viscosity Required for Life
Research by physicist Kostya Trachenko indicates that fundamental physical constants must fall within a narrow band for liquids to flow with viscosities suitable for cellular biology.
Most discussions about why the cosmos can support living organisms focus on astronomy and nuclear physics: whether stars burn long enough to forge heavy elements, or whether gravity is balanced enough to hold planets in stable orbits. But even if a planet forms with abundant water and complex organic molecules, life as a cellular process depends on something far more immediate and mechanical: whether liquids can actually flow. At the microscopic scale, cells require fluids to circulate nutrients, clear waste, and permit biochemical reactions without collapsing or grinding to a halt.
A study published in Science Advances by physicist Kostya Trachenko at Queen Mary University of London suggests that this basic hydrodynamic requirement imposes severe constraints on the universe itself. Trachenko’s theoretical work demonstrated that the universe’s fundamental physical constants may be finely balanced to make life possible, showing that liquids would become either too viscous or too thin to support essential biological functions if these parameters varied even slightly.
The physical properties of any liquid, including water and biological fluids, are governed by fundamental parameters such as the Planck constant, the electric charge of the electron, and the electron’s mass. In Trachenko’s formulation, these constants dictate the fundamental behavior and lower limits of liquid viscosity. If the constants shifted, the intermolecular forces that allow molecules to move past one another would alter, directly undermining the transport processes that allow cells to operate.
The window permitting functional biology appears remarkably narrow. In complex organisms, for instance, fluids like blood must balance between circulating freely through microscopic channels and maintaining enough internal cohesion to transport vital materials. According to the research, blood viscosity would become too thick or too thin with only a few percent change in some fundamental constants. A universe with slightly higher viscosity would see cellular flow cease, while a universe with lower viscosity would disrupt the stability needed for chemical reactions inside cellular environments.
This finding introduces a distinct layer to the classic fine-tuned universe problem. Previous fine-tuning arguments have primarily concentrated on whether physical laws permit stable atoms, chemistry, and stars to emerge from the early universe. Trachenko’s calculations show that having the correct chemical ingredients is not enough: a universe could theoretically possess carbon, hydrogen, and oxygen, yet remain sterile simply because its liquids are physically incapable of functioning inside a living cell.
By linking the deepest constants of quantum mechanics and electromagnetism directly to macroscopic fluid dynamics, the research frames liquid flow not just as an environmental condition, but as a fundamental cosmological constraint. Life requires a universe that can manufacture matter, but it also requires one where that matter can move at the scale of a cell.