Albert Einstein developed his intel- lectual bombshell, general relativity, against a backdrop of all-too-real bombs. World War I profoundly lim- ited scientists’ ability to share ideas
and perform crucial experiments to test
The physicist Karl Schwarzschild managed to contribute while serving as an
artillery officer with the German army on
the Russian front. Schwarzschild’s work
described the curvature of spacetime
outside a spherical, nonrotating massive
object—a result that later proved key to
studying black holes. In a 1915 letter to
Einstein, he wrote, “[ T]he war treated me
kindly enough, in spite of the heavy gunfire,
to allow me to get away from it all and
take this walk in the land of your ideas.”
Schwarzschild succumbed to disease not
Other researchers had similarly bad luck.
In August 1914, the German astronomer
Erwin Freundlich led an expedition to the
Crimea to take measurements during
a total solar eclipse. He and colleagues
hoped to test Einstein’s prediction that the
sun’s gravity would deflect nearby starlight.
But when war broke out before the eclipse,
Russian officials seized the scientists’
equipment and detained them.
The British astronomer Arthur
Eddington performed the experiment
5 years later on the island of Principe,
but he too felt the shadow of the war.
Eddington was a conscientious objector
who nearly landed in prison for refusing
conscription. His colleague, Astronomer
Royal Frank Dyson, was able to obtain an
exemption for Eddington on the condition
that he participate in the expedition. The
measurement—made in 1919, after the
war ended—verified Einstein’s theory, a
result Eddington saw as a tool for peace.
He wrote to Einstein, “It is the best possible thing that could have happened for
scientific relations between England and
MILESTONE: 1914 ment on the overpass, Giaime says that the
ground constantly jiggles by about a millionth of a meter, shaken by seismic waves,
the rumble of nearby trains, and other
things. LIGO physicists have to shield the
mirrors from such vibrations so that they
can see the cavities stretch or shorten by
distances 10 trillion times smaller—just a
billionth the width of an atom.
IN 1915, Einstein explained that gravity
arises when mass and energy warp space
and time, or spacetime. A year later, he predicted that massive objects undergoing the
right kind of oscillating motion should emit
ripples in spacetime—gravitational waves
that zip along at light speed.
For decades that prediction remained
controversial, in part because the mathematics of general relativity is so complicated. Einstein himself at first made a technical error, says Rainer Weiss, a physicist
at the Massachusetts Institute of Technology (MIT) in Cambridge. “Einstein had it
right,” he says, “but then he [messed] up.”
Some theorists argued that the waves were
a mathematical artifact and shouldn’t actually exist. In 1936, Einstein himself briefly
took that mistaken position.
Even if the waves were real, detecting
them seemed impossible, Weiss says. At
By Emily Conover
Relativity and the Great War