A new study from researchers at Queen Mary University of London is offering an unusual perspective on one of physics’ oldest mysteries: why the Universe appears finely tuned for life. Their research suggests that the same physical constants governing the cosmos may also determine whether liquids can flow in ways that make biological life possible.
The findings, published in 2023 in the journal Science Advances, propose that even small changes in the Universe’s fundamental constants could dramatically alter the behavior of liquids such as water and blood. In that scenario, the complex cellular activity required for life on Earth may never have developed.
How Liquid Flow Could Shape the Possibility of Life
At the center of the research is viscosity — the property that determines how easily a liquid flows. While viscosity is familiar in everyday substances like oil, water, or syrup, scientists say it also plays a critical role inside living organisms.
Within cells, liquids must move continuously to transport nutrients, enable proteins to fold properly, and allow molecules to diffuse through microscopic environments. Without the right balance of fluid movement, the chemistry required for life could break down.
The researchers argue that the Universe operates within an extremely narrow “bio-friendly” range in which liquid flow remains suitable for biological systems. If the fundamental constants of physics were altered by only a few percentage points, liquids essential to life could become either far too thick or far too thin.
“Understanding how water flows in a cup turns out to be closely related to the grand challenge to figure out fundamental constants,” physicist Kostya Trachenko said in discussing the research.
“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. For example, if water was as viscous as tar life would not exist in its current form or not exist at all.”
Why Small Changes Could Have Major Consequences
The study suggests the impact would extend far beyond oceans or drinking water. Human blood, cellular fluids, and the biochemical systems that sustain life all rely on carefully balanced flow properties.
According to the researchers, even slight variations in constants such as the Planck constant or the electron charge could disrupt those systems.
“Any change in fundamental constants including an increase or decrease would be equally bad news for flow and for liquid-based life,” Trachenko said.
“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.”
The idea adds a new dimension to long-running debates over “fine-tuning” in physics — the observation that the Universe’s physical laws appear remarkably well suited for the formation of matter, stars, planets, and eventually life.
A New Layer in the Fine-Tuning Debate
For decades, scientists studying cosmic fine-tuning have largely focused on large-scale processes such as star formation and nuclear reactions. Many physicists note that if the strengths of fundamental forces were slightly different, stars might never have produced the heavier elements needed for planets and living organisms.
The new research shifts that discussion to a much smaller scale: the microscopic environments inside living cells.
The study argues that even if stars and galaxies still formed in an alternate universe, life itself might remain impossible if liquids could not move properly within biological systems. In other words, the Universe may need to be compatible not only with matter, but also with the delicate fluid dynamics that sustain living organisms.
Researchers compared the possibility to biological evolution, suggesting that multiple stages of physical “tuning” may have emerged independently over time. While the concept remains speculative, it raises questions about whether stable structures in nature are favored by deeper physical principles that scientists do not yet fully understand.
Later Research Builds on the Theory
Since the original paper was published, additional theoretical studies have continued examining the relationship between viscosity, diffusion, and the laws of physics.
Some researchers have explored how fluid motion inside cells could place additional constraints on the values of fundamental constants, particularly in systems involving molecular motors and other biochemical machinery. Others have investigated whether viscosity itself may arise from universal physical limits rather than being simply a measurable property of liquids.
Together, the work is reshaping discussions around one of science’s most enduring mysteries. Instead of viewing the constants of nature solely through the lens of cosmology or particle physics, scientists are increasingly considering whether the requirements for functioning biological systems should also factor into the equation.
Could Everyday Physics Hold Clues About the Universe?
The theory remains highly speculative, and there is still no widely accepted explanation for why the Universe’s constants have the values scientists observe today. Many physicists caution that more evidence is needed before drawing broader conclusions.
Still, the research opens an unexpected avenue in the search to understand why the Universe appears capable of supporting life. For years, investigations into fundamental constants centered on black holes, stars, and subatomic particles. This work suggests that part of the answer may lie much closer to everyday human experience — in the simple ability of liquids to flow through living cells.
