MAY 2019. DISCOVER 45in 1914. His team arrived, armed with telescopes and
cameras and glass photographic plates, just as war
broke out. Russian soldiers captured Freundlich and
confiscated his instruments.
Freundlich wasn’t the only one watching in 1914.
Astronomers from California’s Lick Observatory also
tried to photograph the eclipse from near Kiev, but
they fared little better. Though spared imprisonment
because they were Americans, the scientists were
thwarted by nature: Clouds obscured their view.
These failures actually may have been a stroke of
luck for Einstein. While reviewing his calculations,
he found errors. His predictions about how much the
stars should move were off. Einstein always was a bet-
ter physicist than mathematician (though the popular
story that he failed math in high school is not true).
By the time Einstein had corrected his mistakes
and published the completed theory of general rela-
tivity, the Great War was in full swing. And after the
war, Germany was in shambles, too wrecked to mount
expeditions to the distant parts of the world where an
eclipse in 1919 would be visible.EDDINGTON’S EXPEDITIONS
Fortunately, a copy of Einstein’s theory wound up
in the hands of Sir Arthur Eddington, director
of the Cambridge Observatory, a math prodigy
and devout Quaker. Ready to be imprisoned as a
conscientious objector, Eddington, like Einstein,
believed in pacifism.
He also believed in Einstein and teamed up
with Astronomer Royal Sir Frank Watson Dyson
to persuade his nation to put relativity to the test.
“Eddington was one of the few English-speaking
scientists who had a thorough understanding of gen-
eral relativity,” says Hurn. “It was seen as being very
German, very incomprehensible — if not completely
wacky — by a lot of people.”
Well aware of how difficult photographing an
eclipse could be, Eddington and Dyson plannedtwo expeditions. Eddington headed for Príncipe, an
island off the west coast of Africa, while a second team
headed to Sobral in Brazil.
The plan was to compare images of the stars taken
during the eclipse with images of the same stars taken
months later when they appeared in their normal
places at night. According to Einstein’s now-corrected
math, stars at the edge of the blotted-out sun would
be displaced from their usual positions by a mere
1.75 arcseconds — about the thickness of a dime seen
from a couple of miles away.
Newton’s theory of gravity made a competing pre-
diction, worked out in detail by a German astronomer
in 1801. His math suggested a shift only half as large,
based on the notion that the force of the sun’s gravity
would pull on the distant stars’ light particles.
When the fateful day arrived in May, Eddington’s
Príncipe team faced bad weather. Thunderstorms
rolled in, clouds obscured the sun, and all but two
of their photographic plates proved worthless. But
for Eddington, ever the true believer, what he saw in
that pair of plates was enough to write his mother:
“The one good plate that I measured gave a result
agreeing with Einstein, and I think I have got a little
confirmation from a second plate.”COSMIC CONFIRMATION
Would confirmation come from the other side of
the Atlantic, where the weather in Sobral was more
cooperative? Dyson had his own issues analyzing
these plates. Photos taken by his primary 16-inch
telescope were out of focus and provided values more
consistent with Newton.
A 4-inch backup telescope lent by an English Jesuit
priest saved the day; it corroborated Eddington’s
observations. (In 1979, modern analysis of the
blurry images from the main telescope also sided
with Einstein.)
After word spread to Germany, it was Einstein’s
turn to write to his mother. “Good news today...German astronomer
Erwin Finlay-
Freundlich tried
to test Einstein’s
theories during a
1914 eclipse, but was
captured by Russian
soldiers instead.
Frank Watson Dyson
went to Brazil in 1919
but had equipment
issues. Arthur
Eddington found
success on an island
DY off Africa.
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