Universe's Constants Sit in Perfect 'Sweet Spot' for Life, Scientists Discover

Researchers at Queen Mary University of London have proposed a striking idea that links the deepest laws of physics to the existence of life itself. Their work suggests that the Universe's fundamental constants sit within an extremely narrow range that allows liquids to flow in ways living cells depend on. If those constants were even slightly different, water, blood, and other life-supporting fluids could behave so differently that complex organisms might never have emerged at all. The study, published in Science Advances, builds on earlier work showing that liquid viscosity is tied directly to fundamental physical constants.

The research extends previous findings into biology, asking whether the same physical rules that shape the cosmos may also quietly determine whether cells can function. Life depends on movement at microscopic scales, with nutrients traveling through cells, proteins folding correctly, and molecules constantly diffusing through watery environments. All of this relies on viscosity, the property that determines how easily a liquid flows. According to the researchers, the Universe appears to operate within a surprisingly narrow "bio-friendly" window where viscosity and diffusion remain suitable for life.

"Understanding how water flows in a cup turns out to be closely related to the grand challenge to figure out fundamental constants. Life processes in and between living cells require motion and it is viscosity that sets the properties of this motion," explains Professor Kostya Trachenko. "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." The team says the consequences would extend far beyond drinking water or oceans, affecting human blood, cellular fluids, and the chemistry that powers life.

The researchers emphasized that even small changes to fundamental constants would be catastrophic. "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," Trachenko noted. This finding adds a new dimension to the long-standing debate about cosmic fine-tuning.

Physicists have long debated why the Universe's constants appear finely tuned, with tiny differences in values such as the electron charge or the strength of fundamental forces potentially preventing stars from forming heavy elements needed for planets and life. This new research suggests that the fine-tuning extends beyond just allowing stars and planets to form – it may also be necessary for the basic fluid dynamics that make life possible. The discovery that viscosity and diffusion are so tightly constrained by fundamental physics provides yet another example of how precisely calibrated our universe appears to be for the emergence and sustainability of complex life forms.