Bacteria, the masters of movement, showcase remarkable physics that challenges conventional understanding. My journey into this unexpected realm began while studying animal locomotion after completing my physics degree. Initially, I felt detached from the core areas of physics—quantum mechanics and cosmology—while observing a research group at the University of California, San Diego. They employed advanced mathematics not for the typical buzzwords but to analyze how various organisms, from snails to microorganisms, navigate their environments.

Initially, I admired the elegance of their work but worried it strayed too far from fundamental physics. As I immersed myself in their research, this concern evolved into an identity crisis. In the theoretical physics community, being distanced from esteemed figures like Einstein felt catastrophic. However, the microorganisms soon captivated me with their astonishing abilities, such as launching DNA fragments at extraordinary speeds or forming ancient genetic networks. Even more intriguing was their behavior, which seemed to defy Newtonian physics.

This revelation transformed how I viewed bacteria and redefined my understanding of what it means to be a physicist.

Microorganisms experience fluid dynamics in a way that diverges significantly from our own. Our perception of water is influenced by our size and swimming speed, while physicists use the Reynolds number to quantify inertia versus viscosity in fluid flow. For humans, this number typically ranges from a few hundred to several thousand, indicating varying degrees of inertia. In stark contrast, bacteria operate in an environment characterized by a Reynolds number of roughly 0.001, meaning their inertia is nearly negligible compared to ours.

To simulate a bacterium’s experience in water, an average human would need to swim through molasses at a mere 1 cm per minute, coasting only a fraction of a millimeter before halting. In such a low-Reynolds-number world, bacteria swim effortlessly, immediately achieving their maximum speed without the concept of acceleration.

In this realm, traditional physics concepts like mass and force lose relevance. Newton's laws become obsolete, as bacteria simply exist in a state of motion or stillness without the forces that govern larger organisms.

Surprisingly, the unique dynamics of bacteria resonated with broader principles of physics. This connection was illuminated for me by a series of articles from Nobel Laureates, demonstrating that the physics governing swimming microorganisms parallels that of certain quantum particles. The realization that gauge theory applies to both realms reshaped my identity, revealing that physicists need not confine themselves to specific subjects but can apply their analytical tools across diverse domains.

My research journey continued as I enrolled in a Ph.D. program at Brown University, where I collaborated with colleagues who used theoretical physics to examine everyday phenomena like swimming and biological growth. It was during this time that I discovered tai chi, seeking a way to alleviate the stress of graduate studies. The practice allowed me to relax, but it also introduced me to the two-person exercise known as tuishou or “Push Hands.”

In Push Hands, competitors strive to unbalance each other without physical strikes, emphasizing fluid movement and connection. This practice taught me to recognize tension in my own body and in my opponent's, a crucial skill for effective practice. The goal is to redirect force rather than resist it, echoing the principles of fluid dynamics that govern bacterial motion.

As I engaged with Push Hands, I found parallels to bacterial swimming. Just as bacteria navigate their environment without a defined center of mass, practitioners learn to absorb and neutralize forces. This connection was profound, revealing that bacteria exhibit tai chi-like mastery in their movements.

Bacteria navigate their surroundings with remarkable agility, adapting their motion without exerting forces on one another. The implications of this observation led me to ponder what would happen if microorganisms could strategically exert forces. My doctoral research evolved, focusing on environments that enable bacteria to perform useful tasks, such as transporting therapeutic agents or assembling complex structures.

Through tai chi, I gained insights that transformed my approach to research, emphasizing a connection between the observer and the observed. This perspective reshaped my understanding of physics, leading me to embrace the role of a “connector”—someone who identifies relationships between seemingly disparate fields.

The journey from bacteria to tai chi has enriched my understanding of physics, revealing that the essence of scientific exploration lies in recognizing connections. These insights extend beyond the confines of academia, suggesting that the everyday experiences and movements of our bodies can illuminate complex scientific principles.

In conclusion, the interplay between tai chi, bacteria, and physics unveils the beauty of interdisciplinary thinking. By recognizing these connections, we can foster a deeper appreciation for the world around us, transcending traditional boundaries in our pursuit of knowledge.