Tiny Changes to Fundamental Constants Could End Life as We Know It

The universe may be rigged in life's favor — and not only in the ways physicists already suspected. In a new theoretical study, physicist Kostya Trachenko of Queen Mary University of London argues that the universe's fundamental constants must sit inside a narrow, bio-friendly window for liquids to flow the way living cells need them to. Shift those numbers even slightly, and the fluids that carry nutrients, clear waste, and let molecules meet would become too thick or too thin for biology to function.

The finding adds a fresh layer to one of science's oldest puzzles: why the basic numbers of nature look so well suited to life. As reported by World News Guru, even tiny changes to the fundamental constants could make liquids unworkable for essential biological processes — a result detailed in a study in the journal Science Advances announced this month.

"Understanding how water flows in a cup turns out to be closely related to the grand challenge to figure out fundamental constants," Trachenko said in the university's announcement, describing how everyday fluid motion connects to the deepest numbers in physics.

Beyond Stars and Carbon: A New Layer of Fine-Tuning

Physicists have long noted that the constants governing nuclear reactions inside stars seem tuned to produce heavy elements like carbon and oxygen — the raw ingredients of life. The new analysis goes further. According to the study, some combinations of fundamental constants could still let stars forge those elements while pushing liquid viscosity so high that cells could never function. In other words, a universe with the right chemistry might still be a universe without life.

Trachenko's interest in the physics of flowing liquids stretches back years. In 2020, he and colleagues established a fundamental lower limit on how runny any liquid can be — a limit set by the constants themselves. The 2023 analysis took that connection much further by asking what it means for biology, as the published paper lays out: the study linked the fundamental constants to the limits of living systems for the first time. A follow-up investigation published in January 2025 examined blood, the most complicated biological fluid, and found its viscosity sits surprisingly close to a value derived from basic physical constants.

Why Fundamental Constants Set the Thickness of Blood

The predictions are startlingly precise for a theoretical model. A change of just a few percent in the Planck constant or the electron charge, the analysis suggests, would push blood viscosity outside the range the human body can handle — too thick to circulate or too thin to do its job. "If water was as viscous as tar, life would not exist in its current form," Trachenko said in the announcement. That small a shift would not need to touch the nuclear reactions that build carbon; the liquids alone would break first.

The blood connection matters because blood is far messier than water. It carries plasma, red blood cells, and platelets that cluster and break apart as flow speeds change. Yet despite all that complexity, its viscosity lands near the theoretical value set by the fundamental constants — hinting that the deep numbers of physics reach all the way up into the circulatory system.

What Skeptics Say — and Why the Window Matters

Perhaps the strangest detail is the timing. The same constants that govern liquid flow also shaped the nuclear reactions inside stars billions of years before the first living cells appeared. As Earth.com summarized in background coverage of the earlier research, water's viscosity may reveal another requirement for life in the universe — one quietly satisfied long before biology showed up to use it.

Not everyone reads fine-tuning as a cosmic mystery. Physicists who favor multiverse explanations counter that an apparently life-friendly universe is exactly what any observer would find: across countless universes with different fundamental constants, ours is simply the one where liquids flow right and someone is around to notice. On that view, the narrow window is a selection effect, not a puzzle demanding an answer.

Trachenko's contribution does not settle that debate, but it sharpens it. By showing that the bio-friendly range for the constants is narrower than the star-friendly range, the work gives both camps a more precise target: any theory of why the numbers are what they are must now explain two separate windows, not one. For readers tracking the search for life beyond Earth, the result also redraws the map — habitability may demand not just water, but water with exactly the right thickness.

For more on how the cosmos keeps surprising researchers, explore the science beat — including how the solar system's lifespan got a rethink.