The birth of a world-changing idea, relativity, and how it was shaped by the social upheaval and bloody horror of the First World War

Einstein's ascent to worldwide celebrity was, in large part, not his own doing. It was because of two wars. The first was the Great War, the industrialized slaughter that bled Europe from 1914 to 1918. While Einstein never held a rifle, the war shaped his life and work for years: falling ill from wartime starvation, unable to send simple letters to his most important colleagues. Simply being a scientist became deeply enmeshed in politics and empire. The second conflict was Einstein's struggle to craft relativity and persuade the world that it was correct. We usually think of scientific discovery as a flash of insight--actually, it is the result of hard work, wrong turns, and difficult conversations with trusted friends. Einstein's magnum opus--the general theory of relativity--needed all of these.

Scientists seeking to confirm Einstein's ideas were arrested as spies. Technical journals were banned as enemy propaganda. Colleagues died in the trenches. And, most frustratingly, Einstein was separated from his most crucial ally by barbed wire and U-boats. This ally was the Quaker astronomer A. S. Eddington, who would go on to convince the world of the truth of relativity and the greatness of Einstein. Eddington took up the cause of that German physicist--whom he had never met--to show how science could triumph over nationalism and hatred.

In May of 1919, when Europe was still in chaos from the war, Eddington led a globe-spanning expedition to catch a fleeting solar eclipse for a rare opportunity to confirm Einstein's bold prediction that light has weight. It was the results of this expedition--the proof of relativity, as many saw it--that put Einstein on front pages around the world. His scientific revolution depended on battles both intellectual and political, fought from Berlin to London to the very edge of the universe.