Scientists have been left stunned after learning that sperm seems to defy one of Isaac Newton's laws of motion.
We all know a small amount of knowledge about sperm - it’s a little tadpole thing that swims and is met by an egg.
However, sperm can apparently defy one of the laws of physics scientists have drawn on for years upon years.
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This discovery was made by Kenta Ishimoto, a mathematical scientist, and his colleagues at Kyoto University.
This fact was found out after the team investigated the sperm's defiance of Newton's third law of motion, which is a law that claims that 'for every action, there is an equal and opposite reaction'.
Newton’s law suggests that opposing forces act against one another.
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This can be seen when two equal-sized marbles strike one another and go on to transfer their force and rebound.
But sperm is different.
The team found that they manage to propel themselves through viscous fluids, rather than creating an equal and opposite reaction and being met with resistance.
Ishimoto and the team looked into these non-reciprocal interactions to try and figure out what was happening, studying experimental data on human sperm as well as modelling the motion of green algae, Chlamydomonas.
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Both use flagella - the little tail bit on sperm - to drive the cells forward, but while highly viscous fluids would usually dissipate their energy, the flagella on sperm can continue to propel the cells forward.
In their research, the team found that sperm tails have an 'odd elasticity', which allows them to whip around without losing much energy to the fluid.
However, this didn't fully explain the propulsion caused by the wave-like motion of the flagella.
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To help explain the process, the researches derived a new term, 'odd elastic modulus', to describe the internal mechanics of flagella.
As the flagella bent to respond to the liquid, they were able to avert the equal and opposite reaction and conserve energy.
Discussing their findings, the researchers said: "From solvable simple models to biological flagellar waveforms for Chlamydomonas and sperm cells, we studied the odd-bending modulus to decipher the nonlocal, nonreciprocal inner interactions within the material."
They continued: "Odd elasticity is not a generic term for activity in solids, but rather a well-defined physical mechanism that generates active forces in solids or in other systems in which a generalized elasticity can be defined without using an elastic potential."
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The team then explained that their findings could have impacts in the real world by helping with the designs of small, self-assembling robots which mimic living materials, or to help better understand the underlying principles of collective behavior.
The new discovery is cool but be prepared to be grossed out by another sperm-related fact.
One thing we wished we didn’t know was that the richest man in the world, Elon Musk isn’t just a billionaire, but is also an eager donor.
Musk has previously taken to Twitter to express his concerns on the birth rate, and might think that he’s going to solve it.
He wrote: “A collapsing birth rate is the biggest danger civilization faces by far.”
He has also tweeted: “Many countries are already well below replacement rate, and the trend is that almost all will be.
"This is simply a fact, not a ‘debunked theory.’ 2.1 kids is replacement rate, and obviously the world as a whole will soon drop below that point.”
According to a New York Times report, the Tesla CEO offered his seed to some friends and acquaintances over the years…and while that’s something I wish I didn’t know, that’s something to keep your mind occupied with.
Britt Jones