Scientists from Kyoto University have made an intriguing discovery about the way sperm swim, defying one of the fundamental laws of physics. The researchers found that the sperm’s flagella, or tails, propel them forward by changing their shape to interact with the fluid. This movement method contradicts Newton’s law of motion, which states that there should be an equal and opposite reaction.
The elasticity of the sperm’s tails also raises questions about their mobility. According to traditional physics, the tails should expend more energy and hinder movement. However, the researchers observed that the sperm whip their tails without releasing much energy into their surroundings. This phenomenon, known as “odd elasticity,” allows the sperm to conserve energy by bending in response to the surrounding liquid.
To conduct their research, the scientists used human sperm cells and algae, as both have flagella that help them swim through liquid. Under a microscope, they observed the pair using their tails to make wave-like movements, which propelled them through the liquid. These movements should theoretically slow down the swimmers, but the flagella averted an equal and opposite reaction, allowing the sperm to maintain their speed.
The findings have significant implications for understanding the mechanics of sperm swimming and could lead to advancements in fertility treatments. It is also an important reminder of the complex and extraordinary capabilities of microscopic organisms.
The study also highlights the potential impact of pollution on sperm health. Other research has shown that sperm rates have declined by more than half since the 1970s, with factors such as men’s waistlines and environmental chemicals contributing to this trend. Understanding the intricacies of sperm movement and the obstacles they face in their surroundings could shed light on potential interventions to improve sperm health.
The scientists’ research adds to the growing body of knowledge about sperm and their unique abilities. The “odd elasticity” observed in this study challenges conventional understanding and invites researchers to explore further. This study was published in Leiden University, emphasizing the importance of interdisciplinary collaboration in unraveling the mysteries of the natural world.