03:46 PM

Tuesday, October 24, 2023

Mathematician Kenta Ishimoto of Kyoto University in Japan has made an unprecedented discovery, demonstrating that sperm secreted by men defies the laws of physics.

With their whip-like tails, spermatozoa propel themselves through viscous fluids, apparently in defiance of Newton’s third law of motion.

The Japanese scientist and his colleagues investigated the surprise to find out how sperm glide through liquids that, in theory, should resist their movement, the Science Alert website reported.

When Newton formulated his famous laws of motion in 1686, he tried to explain the relationship between a body and the forces acting on it using certain precise principles that were not necessary for microscopic particles moving through viscous fluids.

Newton’s third law can be summarized as follows: “For every action there is an equal and opposite reaction.” It refers to a certain symmetry in nature where opposing forces work against each other. In a simple example, two marbles of equal size rolling on the ground and colliding will transfer their force based on this law and bounce.

However, nature is chaotic, and not all physical systems are governed by these laws.

Ishimoto and his colleagues analyzed experimental data on human sperm to model the movement of green algae. Both swim using thin, flexible flagella that extend from the cell body and deform or deform to propel the cells forward.

In general, highly viscous fluids dissipate flagellar energy, preventing sperm or unicellular algae from moving. However, somehow, the flexible flagellum is able to move these cells without being affected by the surrounding environment.

The researchers found that sperm’s tails and flagella have a “peculiar elasticity,” allowing these flexible appendages to move without losing much energy to the surrounding fluid.

But this strange elastic property does not fully explain the impulse generated by the wave motion of the flagellum. Thus, from modeling studies, the researchers derived a new term to describe the internal dynamics of the flagellum, the eccentric modulus of elasticity.

The team says the findings could help design small, self-assembling robots that mimic living things, while modeling methods can be used to better understand the fundamental principles of collective behavior.