[Marxism] How Politics Shaped General Relativity

Louis Proyect lnp3 at panix.com
Sun Nov 8 10:17:35 MST 2015


NY Times, Nov. 8 2015
How Politics Shaped General Relativity
By DAVID KAISER

ON four Thursdays in November 1915 — one lecture each week — Albert 
Einstein rose to the podium at the Prussian Academy of Sciences to 
deliver updates on what he came to call his “general theory of 
relativity.” He was working at a frenzied pace, adjusting details 
between each presentation. By the end of the month, he had arrived at a 
form for his equations that physicists still use today. Elegant and 
crisp, they are brief enough to tweet.

In the 100 years since, Einstein’s theory has been famously successful. 
Physicists and astronomers have applied general relativity to far-flung 
reaches of the cosmos, and no experiment or observation has yet revealed 
a discrepancy. Less commonly understood, however, is how thoroughly the 
research into this profound, abstruse and seemingly otherworldly theory 
was shaped by the messy human dramas of the past century.

 From the outset, Einstein was not optimistic that his theory would be 
quickly accepted. “The theory of gravitation will not find its way into 
my colleagues’ heads for a long time yet, no doubt,” he lamented to a 
friend in 1915.

Some of the barriers to acceptance were conceptual. Isaac Newton had 
argued that there was a universal force of gravity, the incessant 
tugging of one body on another. But Einstein argued that there was no 
“force” of gravity at all. Space and time were as wobbly as a 
trampoline; they could warp, bend or distend in the presence of massive 
objects like the sun. Objects simply moved as straight as they could, 
flowing through curved space-time. This idea could be hard to wrap your 
head around.

But other obstacles were political. The turmoil and disruptions of World 
War I, for example, prevented many people from learning and thinking 
about general relativity. The theory’s earliest converts included a 
Russian mathematician being held in a German prisoner-of-war camp, who 
was unable to enlighten his Russian colleagues for several years; a 
German astronomer being held in a Russian prisoner-of-war camp, who was 
unable to complete his test of one of the theory’s key predictions; and 
another German astronomer, who passed the time while serving in the 
German Army by finding the first exact solutions to Einstein’s 
equations, only to succumb to a deadly disease on the Russian front a 
few weeks later.

The war also controlled how Einstein’s work spread westward. Because he 
was a German civil servant, neither Einstein nor his letters — nor even 
German scientific journals — could cross the English Channel amid the 
naval blockade. Einstein could, however, travel to neutral countries, 
like the Netherlands. He made frequent trips to Leiden, where he 
befriended the great mathematical physicist Willem de Sitter and tutored 
him in general relativity. And de Sitter, in turn, sent a series of 
detailed primers on Einstein’s work to a Cambridge colleague, the 
physicist and astronomer Arthur Eddington.

Eddington, a Quaker and conscientious objector, was concerned that 
wartime resentments were damaging the international scientific 
community. He leapt on Einstein’s relativity as a means of restoring 
harmony. As the historian Matthew Stanley has documented, Eddington’s 
superiors in London and Cambridge lobbied British government officials 
to let him devote his mandatory wartime service to preparing an 
astronomical expedition to test one of Einstein’s major predictions, 
that gravity could bend the path of starlight. By leading a British team 
to test the work of a German physicist, Eddington hoped to “heal the 
wounds of war.”

One year after the armistice that ended World War I, Eddington announced 
that his team’s measurements of the apparent positions of stars during a 
recent eclipse matched Einstein’s predictions. In an interview soon 
afterward, Einstein noted that the public recognition of his 
accomplishment had a political slant. “Today I am described in Germany 
as a ‘German servant,’ and in England as a ‘Swiss Jew,’ ” he said. 
“Should it ever be my fate to be represented as a bête noire, I should, 
on the contrary, become a ‘Swiss Jew’ for the Germans and a ‘German 
servant’ for the English.” Here, he shared with a wink, was yet another 
application of the theory of relativity.

Sadly, events quickly proved Einstein right. Just months after 
Eddington’s announcement, right-wing political opportunists in 
war-ravaged Germany began to organize raucous anti-Einstein rallies. 
Only an effete Jew, they argued, could remove “force” from modern 
physics; those of true Aryan spirit, they went on, shared an intuitive 
sense of “force” from generations of working the land. Soon after the 
Nazis seized power in 1933, they banned the teaching of Einstein’s work 
within the Reich. Einstein settled in Princeton, N.J.; the German 
relativity community was decimated.

After World World II, a new generation of physicists in the United 
States began to focus on relativity from their perch within the 
“military-industrial complex.” Here, political exigencies accelerated a 
deeper appreciation of Einstein’s theory, in unanticipated ways.

In one example, physicists and engineers working on enormous radar 
arrays to detect incoming Soviet missiles calibrated and fine-tuned 
their new system by sending radar pulses to nearby planets. These 
researchers realized that if they timed the return echo from the planets 
with unprecedented accuracy, they could test a subtle prediction of 
Einstein’s: that gravity slows the speed of light as well as bending its 
path. For decades, this “time-delay” test provided the most precise 
measurements available that space-time really did behave as Einstein 
predicted.

Twenty years later, theoretical physicists briefed United States Air 
Force generals on a subtle complication with a new military technology, 
the Global Positioning System. Effects from Earth’s gravity would be 
stronger on the ground than in orbit, the physicists explained, and 
hence clocks on the ground would tick more slowly than those aboard 
satellites. If the clocks disagreed on time, they would also disagree on 
space, and that could spell trouble for this technology. If left 
uncorrected, the tiny differences in clock rates would snowball into 
enormous errors in determining distances. With GPS, the warping of time 
that Einstein imagined assumed operational significance. (Later, GPS was 
opened to the commercial market, and now billions of people rely on 
general relativity to find their place in the world, every single day.)

A century after its creation, Einstein’s beautiful theory continues to 
inspire lofty thoughts — about black holes, supernovae, the big bang. 
The history of Einstein’s work, however, reveals how even the most 
abstract scientific research can be buffeted, derailed and even 
propelled by the most potent force of all: politics.

David Kaiser is a professor at M.I.T., where he teaches physics and the 
history of science. His latest book is “How the Hippies Saved Physics: 
Science, Counterculture, and the Quantum Revival.”




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