Soon American Thanksgiving arrives and a change to note a few things I'm thankful for. This year I'll pick two examples that celebrate tiny asymmetries in nature: our existence and women's sports.
First the universe as we know it. There are several asymmetries in physics that allow us to exist. Two important ones are the amount of antimatter and matter produced in the very early universe and the mass difference between up and down quarks. The matter-antimatter imbalance is easy to think about, but is still one of those fundamental unsolved problems. During the first fractions of a second after everything started particle-anti-particle pairs would be popping in and out of existence at a furious rate. As the universe expanded all that would be left would be pure energy. But something interesting happened. This oscillation slightly favored these oscillating particles to decay as matter particles than antimatter. The asymmetry isn't huge - a part in a billion or so - but we wouldn't be here without it. There are a number of conjectures about the mechanism, but nothing solid.
So the early universe favored matter. Things like electrons and quarks that make up atoms. The neutron has two down and one up quark, the proton two up and one down.1 It turns out down quarks are slightly more massive than up quarks. That means the neutron is more massive - about a tenth of a percent than the proton. On its own the neutron is unstable, decaying into a proton, electron and antineutrino in about fifteen minutes. If the proton was more massive it could decay into a neutron, positron and neutrino. In the heavier proton universe everything would quickly be just neutrons, electrons and neutrinos.. It would be impossible for atoms to form .. no stars, no planets, no us..
What about the radioactive free neutrons in our universe? There's the strong interaction - an interaction resulting from another asymmetry that binds neutrons and protons together at very close ranges. The binding energy prevents the neutron from decaying so we can have atoms that are more complex than hydrogen..
So onto another asymmetry that occurred over thirteen billion years from the beginning - the genetic difference between males and females. Within any given species the differences are very small. They turn out to be profound. Male and female humans have some important differences that can be described as a small asymmetry. This results in two sexes (with some mostly rare differences). There are also a number of genders which aren't related to the genetic asymmetry. Some societies tend equate sex and gender but others, like some North American First Nation Peoples, recognize well over a dozen. I'm solidly with the later group and believe there shouldn't be unfair discrimination.
This is where Title IX is important. A major result of the law was an explosive growth in women's sports in the US. Now fifty years in, the strength of women's sport in American schools has fundamentally changed women's sports globally. Women's sport should be protected category. Biological males receive enormous physical advantages during puberty largely from the hormone testosterone. Biological males that have their testosterone levels reduced to near zero after puberty still have almost all the performance advantage (70 to well over 90 percent) an untreated biological male would have.
A good friend is an Olympian and I've become more familiar with some parts of elite women's sport. A number of biological males are declaring themselves to be trans women.2 While this may or may not be entirely gender identification, these biological males have an advantage over biological females in the vast majority of sports. In sport there three fundamentals people talk about: safety, fairness and inclusivity. Using that order is protective of biological females. Unfortunately some sports and people argue inclusivity and remove fairness and safety.3 The result has been second rate biologically male athletes denying biologically female athletes medals and scholarships and, in some cases, increased injury rates. There's also some intimidation from sponsors to prevent women from speaking up.
But in each category - male and female -you can find what makes sport exciting.
Asymmetries are why we're here. They can also produce social challenges.
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1 I've taken some license here:-)
2 Sports physiologist Ross Tucker has made several podcasts on this that make a good introduction to the biology. The first 35 minutes or so of this podcast episode offer one of the best explanations of the Caster Semenya affair.
3 Some argue that there are women taller and stronger than many men. The argument doesn't hold water. Consider age and weight categories in many sports. They exist to promote fairness and safety. While Sarah stands 196 cm and can lift more than twice her body weight, elite male volleyball players have a strong physical advantage over her. There are male and female distributions for height, weight, strength, lung capacity, blood flow, endurance, etc. In fact, in the longest ultra endurance events - ultra-marthons over 100 miles - women turn out to have an endurance advantage that becomes more significant by 150 miles. If these became popular there should probably be different categories for biological males and biological females.
And on the game I know. Male and female volleyball at the elite level have developed different strategies and tactics as a result of the physical differences. In my mind the women's game involves more finesse, tactics and strategy, while the men's game is more powerful.