Universe's Physical Constants Linked to Life's Liquid Flow

Scientists have uncovered a potential connection between the fundamental physical constants that shape the universe and the precise liquid flow properties required for life to exist. The groundbreaking research, published in Science Advances, extends the idea of cosmic fine-tuning from the formation of stars and galaxies down to the microscopic level of living cells, suggesting a universal bias towards conditions conducive to biological function.

Life on Earth depends heavily on movement at the cellular level. Nutrients must be transported, proteins must fold correctly, and molecules need to diffuse through aqueous environments, all processes governed by viscosity – the measure of a liquid's resistance to flow. The research posits that the universe operates within a remarkably narrow window where viscosity and diffusion rates are suitable for life. Even minor deviations in fundamental constants, such as the electron charge or Planck constant, could render essential biological liquids too thick or too thin for cells to function.

“Understanding how water flows in a cup turns out to be closely related to the grand challenge to figure out fundamental constants,” said Professor of Physics Kostya Trachenko. “Life processes in and between living cells require motion and it is viscosity that sets the properties of this motion. If fundamental constants change, viscosity would change too impacting life as we know it.”

The implications of such a shift would be profound, affecting not only water bodies but also critical biological fluids. “For example, if water was as viscous as tar life would not exist in its current form or not exist at all,” Trachenko explained. “This applies beyond water, so all life forms using the liquid state to function would be affected.” The researchers highlighted that changes to constants could alter the viscosity of blood or cellular fluids, making them unviable for bodily functions. “Any change in fundamental constants including an increase or decrease would be equally bad news for flow and for liquid-based life. We expect the window to be quite narrow: for example, viscosity of our blood would become too thick or too thin for body functioning with only a few per cent change of some fundamental constants such as the Planck constant or electron charge.”

A Cosmic Balancing Act for Biology

The debate surrounding the fine-tuning of the universe's constants has long occupied physicists. Small variations in values like the electron charge could prevent the formation of heavy elements necessary for planets and life. However, this new study introduces a unique perspective by shifting the focus from cosmological scales to cellular biology. It proposes a secondary layer of cosmic fine-tuning: even if the universe produced the right building blocks, life might still be impossible if the liquids within organisms could not flow correctly.

This research suggests that the physical laws not only support the existence of matter but also specifically enable the delicate liquid dynamics essential for life. The authors even speculate that multiple stages of tuning may have occurred, drawing parallels to biological evolution where traits emerge over time. This theoretical framework implies that nature might intrinsically favor physical structures that are stable and conducive to life's fundamental requirements.

Since the initial publication, further theoretical work has expanded upon these ideas. Subsequent analyses have explored how molecular motors and other biochemical machinery within cells place additional constraints on physical constants. Other studies have investigated the deeper physical origins of viscosity itself, with increasing evidence suggesting it is tied to universal physical limits rather than being merely a laboratory-measured property. Together, these investigations are prompting a reevaluation of fundamental physics, incorporating the conditions necessary for flowing liquids and functional cells into the broader cosmological picture.

While the concept remains theoretical and lacks a definitive explanation for the observed values of nature's constants, this research opens an unexpected avenue for understanding one of science's most profound mysteries. The question of why the universe is the way it is, previously explored through black holes, stars, and subatomic particles, may now also find answers in the fundamental properties of liquid flow within living cells.