Scientists Discover Sperm Seem To Bypass a Fundamental Law of Physics

A Kyoto University-led study modeled human sperm and Chlamydomonas flagella to explain how they swim in viscous fluids.

The researchers found that internal active forces can act like “odd elasticity,” producing non-reciprocal traveling waves.

This mechanism helps microscopic swimmers generate motion despite the constraints of Newton’s third law and the scallop theorem.

The work offers a new physics framework for understanding sperm motility and other active biological materials.