Viswanathan K's Thoughts

Large organisms don’t look anything like magnified versions of tiny organisms. Why not? Because of the (physics) principle of scaling. And it’s not just limited t0 physical structure. In So Simple a Beginning , Raghuveer Parthasarathy asks an interesting question: Why can’t a bacterium swim like a whale?   Swimming involves pushing the water to move. There are two aspects that make this action hard: inertia and viscosity. The ratio of these two forces is called the Reynolds number. The higher the Reynolds number, the higher the inertia. Which means the liquid appears turbulent to the act of swimming. The lower the Reynolds number, the higher the viscous force.   Wait, it gets trickier. The Reynolds number also depends on the size of the object trying to swim. To a tiny bacterium, the water has a low Reynolds number. But to a whale, the Reynolds number is huge. This has other consequences: “This fact has deep consequences for how aquatic creatures can or cannot move....

In The Mongol Empire , John May says: “Two of the strangest (things) are that today’s China owes its shape and size… to a barbarian non-Chinese who was its greatest enemy; and that the same barbarian is now honoured as an insider, the founder of a Chinese dynasty.” It also explains why China considers Tibet a part of itself.   No, this tale is not about Genghis Khan.   Genghis’ descendants split the empire. Some ruled the Middle East, others towards Hungary, and the last group a little into China. “Little” is the right word, China was huge and had different rulers in different places. It was on the Chinese side that Kublai was the frontman for his brother, Mönkhe.   After hard fought wins in China, Kublai followed Genghis’s approach. Mass slaughter was perpetrated on the losers only if it would serve as a signal to the next kingdom in their path – surrender and you live, fight and be slaughtered. But if there was no kingdom nearby waiting to be conquered...