Before the year 1868 — as the first railways chugged across the Indian subcontinent, and photography began to challenge painters in Europe — Japan had remained closed to the outside world for almost three centuries. So profound was its intellectual isolation that the Japanese who left their soil and returned were executed to prevent ideas coming from outside; and the ‘construction of ocean-going ships was banned until 1853’.

It is somewhat of a miracle then, that this feudal backwater with medieval technology was able to produce Nobel-quality physics within 30-40 years of its opening up as a result of the Meiji Restoration. The key role in Japan’s scientific upliftment was played by one of the leading scientists of his age — Lord Kelvin (also known as William Thomson) who, on the Emperor’s request, sent a small fleet of his young students to head entire colleges in Japan. These students were known as oyatoi gaikokujin (‘honourable foreign employees’). In a strange turn of events, Japan’s unique relationship with the sea and with earthquakes began to exert its own reverse influence on the march of European science.

John Perry, one of the oyatoi engineers and an assistant of Kelvin, found Japan a fertile ground to study earthquakes, among other things. For this purpose, Perry and his colleagues developed a seismograph to record them, tracing lines of extraordinary waviness and fluctuation. Little did Perry know that this geological investigation would soon pit him against his own mentor — the great Lord Kelvin, who was in Europe busy estimating the age of Earth.

As a mathematical physicist, it has been noted that Kelvin’s most favoured instrument was the theory of Fourier analysis. And indeed, Fourier’s theory was a way to break down complex periodic phenomena (such as the shockwave of an earthquake) into simple components. A good example is the breaking of sunlight into its constituent colours through a prism, or the notes that make up a musical chord.

Fourier’s transform was such a universal prism whose brute analysis could be applied to a vast number of natural phenomena — the cycle of appearing and disappearing sunspots, the tides in a bay, or signals in a telegraph wire (a lot of Kelvin’s wealth came from that). Although, when Fourier invented his method, the purpose was to study the diffusion of heat over time in a solid body,. Taking Fourier’s cue, Kelvin tried to calculate the age of the planet by reverse-engineering the current temperature using Fourier’s mathematics of diffusion. He literally asked, “How long has this solid sphere been cooling to be at the current temperature?” coming to an estimate of 24-400 million years for a solid globe. It is worth mentioning how important this was to people like Darwin, because if evolution was true, the age of the planet would be a central piece of evidence.

Having studied earthquakes in Japan for a long time, Perry had trouble accepting the idea that the core of Earth was solid, as Kelvin had assumed. He proposed that the interior of Earth was fluid, upon which floated the outside shell of a solid crust, just as icebergs float on water. The diffusion of heat through such a fluid sphere would push back the planet’s age to a few billion years, contradicting Kelvin.

Perry wrote to his offended teacher, “the real basis of your calculation is your assumption that the solid earth cannot alter its shape... even in 1000 million years, under the action of forces constantly tending to alter its shape, and yet we see the gradual closing up of passages in a mine, and we know that wrinkling and faults and other changes of shape are always going on in the earth under the action of long-continued forces. I know that solid rock is not like cobbler’s wax, but 1000,000,000 years is a long time, and the forces are great.”

Had Perry’s theory of a fluid core been taken seriously, some scholars now believe, the fact that continents of the Earth have ‘drifted’ large distances over billions of years would have been accepted much earlier.

The fact that Perry was in Japan, surrounded by its art and culture, teaching physics to sake-drenched samurais, may indeed have played a role in shaping his theory. This changing Japan, the hedonistic world of the Edo era with its tradition of woodblock prints called the ukiyo-e (‘pictures of the floating world’), was confronted by Western technology after Meiji reforms. Perhaps its greatest artist, Tsukioka Yoshitoshi was slowly being driven mad with the decline of Japanese culture, a fact he made very explicit in the violence of his images. For him it was the sinking moment of a floating world, a cosmic tug-of-war that shows clearly in his ‘death poem’.

‘...holding back the night

with its increasing brilliance

the summer moon…’

(Rohit Gupta explores the history of science as Compasswallah)

Tweet to him @fadesingh

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