Arthur Eddington

Sir Arthur Eddington (1882–1944) was a British astronomer, mathematician, physicist, science writer, and science "popularizer", somewhat in the mold of Carl Sagan and Neil deGrasse Tyson in modern times.

In the early decades on the 20^th century, two new theories of "modern physics", Relativity and Quantum Mechanics, had come into existence. Both were known for being very abstruse. He popularized them, both for experts and for the general public. He particularly worked on getting relativity better known, both by the scientific community and by the public. General Relativity was something he worked especially hard at.

He is best known for his observations of the bending of light from stars in the vicinity of the sun during a total eclipse. This had been predicted by General Relativity, but the theory was so esoteric that even the scientific community had a difficult time with it. The problem was compounded by the fact that Einstein was German, and the controversy was around the time of World War I. His claimed success (not fully justified—see below) immediately propelled Einstein (and, to a lesser extent, Eddington), to worldwide fame, even though the public still understood virtually nothing about relativity.

Conscientious objector

Eddington was a conscientious objector during World War I. This wasn't a popular position at his time. When general conscription was introduced in 1916, Eddington entered his plea to claim exemption on grounds of conscience, but his university had requested the authorities not to withdraw him from his scientific researches. Eddington had declared:

"My objection to war is based on religious grounds. I cannot believe that God is calling me to go out to slaughter men, many of whom are animated by the same motives of patriotism and supposed religious duty that have sent my countrymen into the field. To assert that it is our religious duty to cast off the moral progress of centuries and take part in the passions and barbarity of war is to contradict my whole conception of what the Christian religion means. Even if the abstention of conscientious objectors were to make the difference between victory and defeat, we cannot truly benefit the nation by wilful disobedience to the divine will."

He was exempted until Aug 1, 1918, and the Astronomer Royal Sir Frank Dyson supported the idea of an expedition - led by Eddington - to observe the solar eclipse of 1919.

The Eclipse of 1919

The next year, Eddington presented his observations to the Royal Society as a proof of the theory of relativity. Recent analysis of Eddington’s work revealed that he was biased in selecting his data, and that overall his data was inconclusive about the theory of relativity.

Eddington next promoted the theory of relativity to the English-speaking world in his Mathematical Theory of Relativity (1923). As the title suggests, this theory was more a mathematical vision of how the universe should be, rather than what it actually was. When a reporter asked Eddington whether only three people even understood the theory, Eddington supposedly arrogantly retorted, "Who's the third?"

But Eddington did not fare well after that. He strongly opposed a theory about massive stars known as white dwarves put forth by Indian physicist Subrahmanyan Chandrasekhar, but Eddington was proven wrong and Chandrasekhar later won a Nobel Prize for his work. Eddington finally lost all credibility when he first insisted that a physical constant (the fine structure constant) measured to be close to 1/136 must precisely equal 1/136 to make the math easier, but when later measurements suggested a value closer to 1/137 Eddington insisted that it must precisely equal to 1/137 instead. He was wrong both times.