MARGINALIA
Judging Einstein
Before most physicists would believe the claims of relativity, they required proof—which would come in the form of a solar eclipse
J. Donald Fernie
Hoping for a Dark Noon
As early as 1912 it seemed possible to capture the necessary
photographs with little fuss. In October of that year, a total solar
eclipse was to run across the northern parts of South America, and
the astronomical observatory of Córdoba in central Argentina
was near enough to mount an expedition. Unhappily, almost all of
South America was under clouds that day.
Another suitable eclipse loomed in August 1914, running northwest to
southeast across eastern Europe. Erwin Freundlich, a young German
astronomer, was determined to test Einstein's theory but encountered
grave difficulty raising money for the trip. The scientific
establishment in Germany was uninterested in paying for it, leading
Einstein himself to offer his own none-too-abundant finances. With
so few options, Freundlich appealed to other countries for
collaborators that would help fund the expedition. He had only one
taker: William Wallace Campbell and a team from the Lick Observatory
in California. Later, the Berlin Academy provided additional support.
The eclipse was due August 21, but the team of Germans and Americans
established a camp near Kiev well before that date to prepare for
the event. Unfortunately, history intervened: On August 1, 1914,
Germany declared war on Russia, and the German astronomers were
taken prisoner. Russian forces expelled the older scientists and
held the younger ones as prisoners of war. The Russians did allow
the Americans to stay for the eclipse, but again the sky was totally
clouded out. Campbell later wrote "I never knew before how
keenly an eclipse astronomer feels his disappointment through
clouds. One wishes that he could come home by the back door and see nobody."
The next year, at the height of the First World War, Einstein
published his general theory of relativity. This timing greatly
complicated the theory's dissemination because German scientific
journals were then unavailable to the English-speaking world. It was
an astronomer from neutral Holland who brought word of the new
theory to Britain. Moreover, Britain was going through a period of
almost hysterical opposition to all things German. Ardently opposed
to this mindless, pervasive hatred, a young British astrophysicist
named Arthur Stanley Eddington stood almost alone. Eddington was not
only a rising star in astronomy but a Quaker—a religious
pacifist. As such, he refused to fight in the war, although he was
willing to risk his life providing aid to civilians caught in the
violence. Because of his beliefs, Eddington lived on the verge of
imprisonment during much of the war and suffered vicious attacks for
his pacifism and efforts to counter his peers' nationalistic
hostility toward German science.
Eddington learned of Einstein's general theory from the Dutch
astronomer Willem de Sitter and was immediately taken with it. He
was almost certainly the first (and, for a while, the only)
English-speaker to understand the theory and appreciate its
significance. Eddington grasped the fact that Einstein's new work
meant that the eclipse experiment was an even more significant test
of relativity—the general theory predicted twice as much
deflection of light rays passing the Sun as did the special theory.
Another suitable eclipse would occur in 1919, and although in 1915
there was no immediate hope for peace, the British Astronomer Royal,
Frank Dyson, began to lay plans (no doubt at Eddington's prompting)
for an expedition to photograph the event. Eddington, of course, was
eager to lead such an expedition but worried that his uncertain
standing with the authorities might cause difficulties for the
project. Then, in a stroke of genius, Dyson wrote a carefully worded
letter to officialdom. In response, the government notified
Eddington that he was lucky so far in having avoided prison, and
that his only hope of remaining that way was to lead Dyson's
expedition, whether Eddington liked it or not! Eddington dutifully
bowed to the hoped-for ultimatum.
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